Hydrocarbon Gas Processing
A process and apparatus for the recovery of ethane, ethylene, propane, propylene, and heavier hydrocarbon components from a hydrocarbon gas stream is disclosed. The stream is cooled and divided into first and second streams. The first stream is further cooled to condense substantially all of it and is thereafter expanded to the fractionation tower pressure and supplied to the fractionation tower at a first mid-column feed position. The second stream is expanded to the tower pressure and is then supplied to the column at a second mid-column feed position. A distillation stream is withdrawn from the column below the feed point of the second stream and compressed to higher pressure, and is then directed into heat exchange relation with the tower overhead vapor stream to cool the distillation stream and condense substantially all of it, forming a condensed stream. At least a portion of the condensed stream is directed to the fractionation tower as its top feed. The quantities and temperatures of the feeds to the fractionation tower are effective to maintain the overhead temperature of the fractionation tower at a temperature whereby the major portion of the desired components is recovered. In other embodiments, the distillation stream is withdrawn from the column above the feed point of the second stream.
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This invention relates to a process for the separation of a gas containing hydrocarbons. The applicants claim the benefits under Title 35, United States Code, Section 119(e) of prior U.S. Provisional Application Nos. 60/848,299 which was filed on Sep. 28, 2006 and 60/897,683 which was filed on Jan. 25, 2007.
BACKGROUND OF THE INVENTIONEthylene, ethane, propylene, propane, and/or heavier hydrocarbons can be recovered from a variety of gases, such as natural gas, refinery gas, and synthetic gas streams obtained from other hydrocarbon materials such as coal, crude oil, naphtha, oil shale, tar sands, and lignite. Natural gas usually has a major proportion of methane and ethane, i.e., methane and ethane together comprise at least 50 mole percent of the gas. The gas also contains relatively lesser amounts of heavier hydrocarbons such as propane, butanes, pentanes, and the like, as well as hydrogen, nitrogen, carbon dioxide, and other gases.
The present invention is generally concerned with the recovery of ethylene, ethane, propylene, propane, and heavier hydrocarbons from such gas streams. A typical analysis of a gas stream to be processed in accordance with this invention would be, in approximate mole percent, 90.5% methane, 4.1% ethane and other C2 components, 1.3% propane and other C3 components, 0.4% iso-butane, 0.3% normal butane, 0.5% pentanes plus, and 2.6% carbon dioxide, with the balance made up of nitrogen. Sulfur containing gases are also sometimes present.
The historically cyclic fluctuations in the prices of both natural gas and its natural gas liquid (NGL) constituents have at times reduced the incremental value of ethane, ethylene, propane, propylene, and heavier components as liquid products. This has resulted in a demand for processes that can provide more efficient recoveries of these products, for processes that can provide efficient recoveries with lower capital investment and lower operating costs, and for processes that can be easily adapted or adjusted to vary the recovery of a specific component over a broad range. Available processes for separating these materials include those based upon cooling and refrigeration of gas, oil absorption, and refrigerated oil absorption. Additionally, cryogenic processes have become popular because of the availability of economical equipment that produces power while simultaneously expanding and extracting heat from the gas being processed. Depending upon the pressure of the gas source, the richness (ethane, ethylene, and heavier hydrocarbons content) of the gas, and the desired end products, each of these processes or a combination thereof may be employed.
The cryogenic expansion process is now generally preferred for natural gas liquids recovery because it provides maximum simplicity with ease of startup, operating flexibility, good efficiency, safety, and good reliability. U.S. Pat. Nos. 3,292,380; 4,061,481; 4,140,504; 4,157,904; 4,171,964; 4,185,978; 4,251,249; 4,278,457; 4,519,824; 4,617,039; 4,687,499; 4,689,063; 4,690,702; 4,854,955; 4,869,740; 4,889,545; 5,275,005; 5,555,748; 5,568,737; 5,771,712; 5,799,507; 5,881,569; 5,890,378; 5,983,664; 6,182,469; 6,712,880; 6,915,662; 7,191,617; 7,219,513; reissue U.S. Pat. No. 33,408; and co-pending application Ser. No. 11/430,412 describe relevant processes (although the description of the present invention in some cases is based on different processing conditions than those described in the cited patents and applications).
In a typical cryogenic expansion recovery process, a feed gas stream under pressure is cooled by heat exchange with other streams of the process and/or external sources of refrigeration such as a propane compression-refrigeration system. As the gas is cooled, liquids may be condensed and collected in one or more separators as high-pressure liquids containing some of the desired C2+ or C3+ components. Depending on the richness of the gas and the amount of liquids formed, the high-pressure liquids may be expanded to a lower pressure and fractionated. The vaporization occurring during expansion of the liquids results in further cooling of the stream. Under some conditions, pre-cooling the high pressure liquids prior to the expansion may be desirable in order to further lower the temperature resulting from the expansion. The expanded stream, comprising a mixture of liquid and vapor, is fractionated in a distillation (demethanizer or deethanizer) column. In the column, the expansion cooled stream(s) is (are) distilled to separate residual methane, nitrogen, and other volatile gases as overhead vapor from the desired C2 components, C3 components, and heavier hydrocarbon components as bottom liquid product, or to separate residual methane, C2 components, nitrogen, and other volatile gases as overhead vapor from the desired C3 components and heavier hydrocarbon components as bottom liquid product.
If the feed gas is not totally condensed (typically it is not), a portion of the vapor remaining from the partial condensation can be passed through a work expansion machine or engine, or an expansion valve, to a lower pressure at which additional liquids are condensed as a result of further cooling of the stream. The pressure after expansion is essentially the same as the pressure at which the distillation column is operated. The combined vapor-liquid phases resulting from the expansion are supplied as feed to the column.
The remaining portion of the vapor is cooled to substantial condensation by heat exchange with other process streams, e.g., the cold fractionation tower overhead. Some or all of the high-pressure liquid may be combined with this vapor portion prior to cooling. The resulting cooled stream is then expanded through an appropriate expansion device, such as an expansion valve, to the pressure at which the demethanizer is operated. During expansion, a portion of the liquid will vaporize, resulting in cooling of the total stream. The flash expanded stream is then supplied as top feed to the demethanizer. Typically, the vapor portion of the expanded stream and the demethanizer overhead vapor combine in an upper separator section in the fractionation tower as residual methane product gas. Alternatively, the cooled and expanded stream may be supplied to a separator to provide vapor and liquid streams. The vapor is combined with the tower overhead and the liquid is supplied to the column as a top column feed.
In the ideal operation of such a separation process, the residue gas leaving the process will contain substantially all of the methane in the feed gas with essentially none of the heavier hydrocarbon components and the bottoms fraction leaving the demethanizer will contain substantially all of the heavier hydrocarbon components with essentially no methane or more volatile components. In practice, however, this ideal situation is not obtained for two main reasons. The first reason is that the conventional demethanizer is operated largely as a stripping column. The methane product of the process, therefore, typically comprises vapors leaving the top fractionation stage of the column, together with vapors not subjected to any rectification step. Considerable losses of C3 and C4+ components occur because the top liquid feed contains substantial quantities of these components and heavier hydrocarbon components, resulting in corresponding equilibrium quantities of C3 components, C4 components, and heavier hydrocarbon components in the vapors leaving the top fractionation stage of the demethanizer. The loss of these desirable components could be significantly reduced if the rising vapors could be brought into contact with a significant quantity of liquid (reflux) capable of absorbing the C3 components, C4 components, and heavier hydrocarbon components from the vapors.
The second reason that this ideal situation cannot be obtained is that carbon dioxide contained in the feed gas fractionates in the demethanizer and can build up to concentrations of as much as 5% to 10% or more in the tower even when the feed gas contains less than 1% carbon dioxide. At such high concentrations, formation of solid carbon dioxide can occur depending on temperatures, pressures, and the liquid solubility. It is well known that natural gas streams usually contain carbon dioxide, sometimes in substantial amounts. If the carbon dioxide concentration in the feed gas is high enough, it becomes impossible to process the feed gas as desired due to blockage of the process equipment with solid carbon dioxide (unless carbon dioxide removal equipment is added, which would increase capital cost substantially). The present invention provides a means for generating a liquid reflux stream that will improve the recovery efficiency for the desired products while simultaneously substantially mitigating the problem of carbon dioxide icing.
In recent years, the preferred processes for hydrocarbon separation use an upper absorber section to provide additional rectification of the rising vapors. The source of the reflux stream for the upper rectification section is typically a recycled stream of residue gas supplied under pressure. The recycled residue gas stream is usually cooled to substantial condensation by heat exchange with other process streams, e.g., the cold fractionation tower overhead. The resulting substantially condensed stream is then expanded through an appropriate expansion device, such as an expansion valve, to the pressure at which the demethanizer is operated. During expansion, a portion of the liquid will usually vaporize, resulting in cooling of the total stream. The flash expanded stream is then supplied as top feed to the demethanizer. Typically, the vapor portion of the expanded stream and the demethanizer overhead vapor combine in an upper separator section in the fractionation tower as residual methane product gas. Alternatively, the cooled and expanded stream may be supplied to a separator to provide vapor and liquid streams, so that thereafter the vapor is combined with the tower overhead and the liquid is supplied to the column as a top column feed. Typical process schemes of this type are disclosed in U.S. Pat. Nos. 4,889,545; 5,568,737; and 5,881,569, and in Mowrey, E. Ross, “Efficient, High Recovery of Liquids from Natural Gas Utilizing a High Pressure Absorber”, Proceedings of the Eighty-First Annual Convention of the Gas Processors Association, Dallas, Tex., Mar. 11-13, 2002. Unfortunately, these processes require the use of a large amount of compression power to provide the motive force for recycling the reflux stream to the demethanizer, adding to both the capital cost and the operating cost of facilities using these processes.
The present invention also employs an upper rectification section (or a separate rectification column in some embodiments). However, the reflux stream for this rectification section is provided by using a side draw of the vapors rising in a lower portion of the tower. By modestly elevating its pressure, a significant quantity of liquid can be condensed in this side draw stream, often using only the refrigeration available in the cold vapor leaving the upper rectification section. This condensed liquid, which is predominantly liquid methane, can then be used to absorb C2 components, C3 components, C4 components, and heavier hydrocarbon components from the vapors rising through the upper rectification section and thereby capture these valuable components in the bottom liquid product from the demethanizer.
Heretofore, such a side draw feature has been employed in C2+ recovery systems, as illustrated in the assignee's U.S. Patent No. 7,191,617. Surprisingly, applicants have found that elevating the pressure of the side draw feature of the assignee's U.S. Pat. No. 7,191,617 invention improves C3+ recoveries without sacrificing C2 component recovery levels and improves the system efficiency, while simultaneously substantially mitigating the problem of carbon dioxide icing.
In accordance with the present invention, it has been found that C3 and C4+ recoveries in excess of 99 percent can be obtained with no loss in C2+ component recovery. The present invention provides the further advantage of being able to maintain in excess of 99 percent recovery of the C3 and C4+ components as the recovery of C2 components is adjusted from high to low values. In addition, the present invention makes possible essentially 100 percent separation of methane and lighter components from the C2 components and heavier components while maintaining the same recovery levels as the prior art and improving the safety factor with respect to the danger of carbon dioxide icing. The present invention, although applicable at lower pressures and warmer temperatures, is particularly advantageous when processing feed gases in the range of 400 to 1500 psia [2,758 to 10,342 kPa(a)] or higher under conditions requiring NGL recovery column overhead temperatures of −50° F. [−46° C.] or colder.
For a better understanding of the present invention, reference is made to the following examples and drawings. Referring to the drawings:
In the following explanation of the above figures, tables are provided summarizing flow rates calculated for representative process conditions. In the tables appearing herein, the values for flow rates (in moles per hour) have been rounded to the nearest whole number for convenience. The total stream rates shown in the tables include all non-hydrocarbon components and hence are generally larger than the sum of the stream flow rates for the hydrocarbon components. Temperatures indicated are approximate values rounded to the nearest degree. It should also be noted that the process design calculations performed for the purpose of comparing the processes depicted in the figures are based on the assumption of no heat leak from (or to) the surroundings to (or from) the process. The quality of commercially available insulating materials makes this a very reasonable assumption and one that is typically made by those skilled in the art.
For convenience, process parameters are reported in both the traditional British units and in the units of the Systeme International d'Unites (SI). The molar flow rates given in the tables may be interpreted as either pound moles per hour or kilogram moles per hour. The energy consumptions reported as horsepower (HP) and/or thousand British Thermal Units per hour (MBTU/Hr) correspond to the stated molar flow rates in pound moles per hour. The energy consumptions reported as kilowatts (kW) correspond to the stated molar flow rates in kilogram moles per hour.
DESCRIPTION OF THE PRIOR ARTThe feed stream 31 is cooled in heat exchanger 10 by heat exchange with cool residue gas at −28° F. [−33° C.] (stream 48a), demethanizer reboiler liquids at 35° F. [2° C.] (stream 41), demethanizer lower side reboiler liquids at −10° F. [−23° C.] (stream 40), and demethanizer upper side reboiler liquids at −79° F. [−62° C.] (stream 39). The cooled stream 31a enters separator 11 at −15° F. [−26° C.] and 1030 psia [7,102 kPa(a)] where the vapor (stream 32) is separated from the condensed liquid (stream 33). The separator liquid (stream 33) is expanded to the operating pressure (approximately 432 psia [2,976 kPa(a)]) of fractionation tower 19 by expansion valve 12, cooling stream 33a to −39° F. [−39° C.] before it is supplied to fractionation tower 19 at a lower mid-column feed point.
The vapor (stream 32) from separator 11 is divided into two streams, 35 and 36. Stream 35, containing about 36% of the total vapor, passes through heat exchanger 15 in heat exchange relation with the cold residue gas at −127° F. [−88° C.] (stream 48) where it is cooled to substantial condensation. The resulting substantially condensed stream 35a at −123° F. [−86° C.] is then flash expanded through expansion valve 16 to the operating pressure of fractionation tower 19. During expansion a portion of the stream is vaporized, resulting in cooling of the total stream to −134° F. [−92° C.]. The expanded stream 35b is supplied to fractionation tower 19 at an upper mid-column feed point.
The remaining 64% of the vapor from separator 11 (stream 36) enters a work expansion machine 17 in which mechanical energy is extracted from this portion of the high pressure feed. The machine 17 expands the vapor substantially isentropically to the tower operating pressure, with the work expansion cooling the expanded stream 36a to a temperature of approximately −90° F. [−68° C.]. The typical commercially available expanders are capable of recovering on the order of 80-88% of the work theoretically available in an ideal isentropic expansion. The work recovered is often used to drive a centrifugal compressor (such as item 18) that can be used to re-compress the residue gas (stream 48b), for example. The partially condensed expanded stream 36a is thereafter supplied as feed to fractionation tower 19 a second lower mid-column feed point.
The demethanizer in tower 19 is a conventional distillation column containing a plurality of vertically spaced trays, one or more packed beds, or some combination of trays and packing. The demethanizer tower consists of two sections: an upper absorbing (rectification) section 19a that contains the trays and/or packing to provide the necessary contact between the vapor portion of the expanded streams 35b and 36a rising upward and cold liquid falling downward to condense and absorb the C2 components, C3 components, and heavier components; and a lower stripping (demethanizing) section 19b that contains the trays and/or packing to provide the necessary contact between the liquids falling downward and the vapors rising upward. The stripping section 19b also includes reboilers (such as trim reboiler 20 and the reboiler and side reboilers described previously) which heat and vaporize a portion of the liquids flowing down the column to provide the stripping vapors which flow up the column to strip the liquid product, stream 42, of methane and lighter components. Stream 36a enters demethanizer 19 at an intermediate feed position located in the lower region of absorbing section 19a of demethanizer 19. The liquid portion of the expanded stream commingles with liquids falling downward from the absorbing section 19a and the combined liquid continues downward into the stripping section 19b of demethanizer 19. The vapor portion of the expanded stream rises upward through absorbing section 19a and is contacted with cold liquid falling downward to condense and absorb the C2 components, C3 components, and heavier components.
A portion of the distillation vapor (stream 43) is withdrawn from the upper region of stripping section 19b. This stream is then cooled from −112° F. [−80° C.] to −130° F. [−90° C.] and partially condensed (stream 43a) in heat exchanger 22 by heat exchange with the cold demethanizer overhead stream 38 exiting the top of demethanizer 19 at −134° F. [−92° C]. The cold demethanizer overhead stream is warmed slightly to −126° F. [−88° C.] (stream 38a) as it cools and condenses at least a portion of stream 43.
The operating pressure in reflux separator 23 (428 psia [2,951 kPa(a)]) is maintained slightly below the operating pressure of demethanizer 19. This provides the driving force which causes distillation vapor stream 43 to flow through heat exchanger 22 and thence into the reflux separator 23 wherein the condensed liquid (stream 45) is separated from the uncondensed vapor (stream 44). Stream 44 then combines with the warmed demethanizer overhead stream 38a from heat exchanger 22 to form cold residue gas stream 48 at −127° F. [−88° C.].
The liquid stream 45 from reflux separator 23 is pumped by pump 24 to a pressure slightly above the operating pressure of demethanizer 19, and stream 45a is then supplied as cold top column feed (reflux) to demethanizer 19. This cold liquid reflux absorbs and condenses the propane and heavier components rising in the upper rectification region of absorbing section 19a of demethanizer 19.
In stripping section 19b of demethanizer 19, the feed streams are stripped of their methane and lighter components. The resulting liquid product (stream 42) exits the bottom of tower 19 at 52° F. [11° C.], based on a typical specification of a methane to ethane ratio of 0.025:1 on a molar basis in the bottom product. The distillation vapor stream forming the tower overhead (stream 38) is warmed in heat exchanger 22 as it provides cooling to distillation stream 43 as described previously, then combines with stream 44 to form the cold residue gas stream 48. The residue gas passes countercurrently to the incoming feed gas in heat exchanger 15 where it is heated to −28° F. [−33° C.] (stream 48a), and in heat exchanger 10 where it is heated to 107° F. [42° C.] (stream 48b) as it provides cooling as previously described. The residue gas is then re-compressed in two stages, compressor 18 driven by expansion machine 17 and compressor 27 driven by a supplemental power source. After stream 48d is cooled to 120° F. [49° C.] in discharge cooler 28, the residue gas product (stream 48e) flows to the sales gas pipeline at 1040 psia [7,171 kPa(a)].
A summary of stream flow rates and energy consumption for the process illustrated in
In the simulation of the
The vapor (stream 32) from separator 11 is divided into two streams, 34 and 36. Stream 34, containing about 22% of the total vapor, may in some embodiments be combined with a portion (stream 47) of separator liquid stream 33 to form combined stream 35. Stream 34 or 35, as the case may be, passes through heat exchanger 15 in heat exchange relation with the cold residue gas at −105° F. [−76° C.] (stream 38a) where it is cooled to substantial condensation. The resulting substantially condensed stream 35a at −101° F. [−74° C.] is then flash expanded through expansion valve 16 to the operating pressure of fractionation tower 19. During expansion a portion of the stream is vaporized, resulting in cooling of the total stream. In the process illustrated in
The remaining 78% of the vapor from separator 11 (stream 36) enters a work expansion machine 17 in which mechanical energy is extracted from this portion of the high pressure feed. The machine 17 expands the vapor substantially isentropically to the tower operating pressure, with the work expansion cooling the expanded stream 36a to a temperature of approximately −102° F. [−74° C.]. The partially condensed expanded stream 36a is thereafter supplied as feed to fractionation tower 19 a second lower mid-column feed point.
The demethanizer in tower 19 is a conventional distillation column containing a plurality of vertically spaced trays, one or more packed beds, or some combination of trays and packing. The demethanizer tower consists of two sections: an upper absorbing (rectification) section 19a that contains the trays and/or packing to provide the necessary contact between the vapor portion of the expanded streams 35b and 36a rising upward and cold liquid falling downward to condense and absorb the C2 components, C3 components, and heavier components; and a lower stripping (demethanizing) section 19b that contains the trays and/or packing to provide the necessary contact between the liquids falling downward and the vapors rising upward. The stripping section 19b also includes reboilers (such as trim reboiler 20 and the reboiler and side reboilers described previously) which heat and vaporize a portion of the liquids flowing down the column to provide the stripping vapors which flow up the column to strip the liquid product, stream 42, of methane and lighter components. Stream 36a enters demethanizer 19 at an intermediate feed position located in the lower region of absorbing section 19a of demethanizer 19. The liquid portion of the expanded stream commingles with liquids falling downward from the absorbing section 19a and the combined liquid continues downward into the stripping section 19b of demethanizer 19. The vapor portion of the expanded stream rises upward through absorbing section 19a and is contacted with cold liquid falling downward to condense and absorb the C2 components, C3 components, and heavier components.
A portion of the distillation vapor (stream 43) is withdrawn from the upper region of stripping section 19b at −108° F. [−78° C.] below expanded stream 36a and is compressed to approximately 609 psia [4,199 kPa(a)] by vapor compressor 21. The compressed stream 43a is then cooled from −78° F. [−61° C.] to −125° F. [−87° C.] and substantially condensed (stream 43b) in heat exchanger 22 by heat exchange with the cold demethanizer overhead stream 38 exiting the top of demethanizer 19 at −129° F. [−89° C.]. The cold demethanizer overhead stream is warmed to −105° F. [−76° C.] (stream 38a) as it cools and condenses stream 43a.
Since substantially condensed stream 43b is at a pressure greater than the operating pressure of demethanizer 19, it is flash expanded through expansion valve 25 to the operating pressure of fractionation tower 19. During expansion a small portion of the stream is vaporized, resulting in cooling of the total stream to −132° F. [−91° C.]. The expanded stream 43c is then supplied as cold top column feed (reflux) to demethanizer 19. The vapor portion (if any) of stream 43c combines with the distillation vapor rising from the upper fractionation stage to form residue gas stream 38, while the cold liquid reflux portion absorbs and condenses the C2 components, C3 components, and heavier components rising in the upper rectification region of absorbing section 19a of demethanizer 19.
In stripping section 19b of demethanizer 19, the feed streams are stripped of their methane and lighter components. The resulting liquid product (stream 42) exits the bottom of tower 19 at 66° F. [19° C.]. The distillation vapor stream forming cold residue gas stream 38 is warmed in heat exchanger 22 as it provides cooling to compressed distillation stream 43a as described previously. The residue gas (stream 38a) passes countercurrently to the incoming feed gas in heat exchanger 15 where it is heated to −66° F. [−54° C.] (stream 38b), and in heat exchanger 10 where it is heated to 110° F. [43° C.] (stream 38c) as it provides cooling as previously described. The residue gas is then re-compressed in two stages, compressor 18 driven by expansion machine 17 and compressor 27 driven by a supplemental power source. After stream 38e is cooled to 120° F. [49° C.] in discharge cooler 28, the residue gas product (stream 38f) flows to the sales gas pipeline at 1040 psia [7,171 kPa(a)].
A summary of stream flow rates and energy consumption for the process illustrated in
A comparison of Tables I and II shows that, compared to the prior art, the present invention maintains essentially the same ethane recovery (83.05% versus 83.06%), but improves both the propane recovery (99.33% versus 98.50%) and butanes+ recovery (99.97% versus 99.94%). Comparison of Tables I and II further shows that these increased yields were achieved using less horsepower than the prior art (11,389 HP versus 12,464 HP, or more than 8% less).
There are three primary factors that account for the improved efficiency of the present invention. First, the boost in pressure provided by vapor compressor 21 allows the column overhead (stream 38) to condense all of distillation vapor stream 43, unlike the prior art process which can condense only a fraction of the stream. As a result, the top reflux stream (stream 43c) for the present invention is more than 5 times greater than that of the prior art (stream 45a), providing much more efficient rectification in the upper region of absorbing section 19a. Second, with the increase in the quantity of the top reflux stream possible with the present invention, the quantity of secondary reflux stream 35b can be correspondingly less without reducing the product yields. This in turn results in more flow (stream 36) to expansion machine 17 and the resultant increase in the energy recovered to power compressor 18, thereby reducing the power requirements of compressor 27. Third, the more efficient rectification provided by stream 43c in the upper region of absorbing section 19a allows operating demethanizer 19 at a higher pressure without reducing the product yields, further reducing the power requirements of compressor 27.
A further advantage of the present invention is a reduced likelihood of carbon dioxide icing.
Also plotted in
Line 73 in
The shift in the operating conditions of the
Another advantage of the present invention is a reduction in the amount of carbon dioxide leaving demethanizer 19 in liquid product stream 42. Comparing stream 42 in Table I for the prior art
One of the inherent features in the operation of a demethanizer column to recover C2 components is that the column must fractionate between the methane that is to leave the tower in its overhead product (vapor stream 38) and the C2 components that are to leave the tower in its bottom product (liquid stream 42). However, the relative volatility of carbon dioxide lies between that of methane and C2 components, causing the carbon dioxide to appear in both terminal streams. Further, carbon dioxide and ethane form an azeotrope, resulting in a tendency for carbon dioxide to accumulate in the intermediate fractionation stages of the column and thereby cause large concentrations of carbon dioxide to develop in the tower liquids.
The reflux streams for absorbing section 19a in demethanizer 19 of the prior art
An alternative embodiment of the present invention is shown in
In the simulation of the
The vapor (stream 32) from separator 11 is divided into two streams, 34 and 36. Stream 34, containing about 23% of the total vapor, may in some embodiments be combined with a portion (stream 47) of separator liquid stream 33 to form combined stream 35. Stream 34 or 35, as the case may be, passes through heat exchanger 15 in heat exchange relation with the cold residue gas at −106° F. [−77° C.] (stream 38a) where it is cooled to substantial condensation. The resulting substantially condensed stream 35a at −102° F. [−74° C.] is then flash expanded through expansion valve 16 to the operating pressure of fractionation tower 19. During expansion a portion of the stream is vaporized, resulting in cooling of the total stream. In the process illustrated in
The remaining 77% of the vapor from separator 11 (stream 36) enters a work expansion machine 17 in which mechanical energy is extracted from this portion of the high pressure feed. The machine 17 expands the vapor substantially isentropically to the tower operating pressure, with the work expansion cooling the expanded stream 36a to a temperature of approximately −101° F. [−74° C.]. The partially condensed expanded stream 36a is thereafter supplied as feed to fractionation tower 19 a second lower mid-column feed point.
A portion of the distillation vapor (stream 43) is withdrawn from the lower region of absorbing section 19a of demethanizer 19 at −113° F. [−81° C.] above expanded stream 36a and is compressed to approximately 619 psia [4,266 kPa(a)] by vapor compressor 21. The compressed stream 43a is then cooled from −84° F. [−65° C.] to −124° F. [−87° C.] and substantially condensed (stream 43b) in heat exchanger 22 by heat exchange with the cold demethanizer overhead stream 38 exiting the top of demethanizer 19 at −128° F. [−89° C.]. The cold demethanizer overhead stream is warmed to −106° F. [−77° C.] (stream 38a) as it cools and condenses stream 43a.
Since substantially condensed stream 43b is at a pressure greater than the operating pressure of demethanizer 19, it is flash expanded through expansion valve 25 to the operating pressure of fractionation tower 19. During expansion a small portion of the stream is vaporized, resulting in cooling of the total stream to −131° F. [−91° C.]. The expanded stream 43c is then supplied as cold top column feed (reflux) to demethanizer 19. The vapor portion (if any) of stream 43c combines with the distillation vapor rising from the upper fractionation stage to form residue gas stream 38, while the cold liquid reflux portion absorbs and condenses the C2 components, C3 components, and heavier components rising in the upper rectification region of absorbing section 19a of demethanizer 19.
In stripping section 19b of demethanizer 19, the feed streams are stripped of their methane and lighter components. The resulting liquid product (stream 42) exits the bottom of tower 19 at 70° F. [21° C.]. The distillation vapor stream forming cold residue gas stream 38 is warmed in heat exchanger 22 as it provides cooling to compressed distillation stream 43a as described previously. The residue gas (stream 38a) passes countercurrently to the incoming feed gas in heat exchanger 15 where it is heated to −66° F. [−55° C.] (stream 38b), and in heat exchanger 10 where it is heated to 110° F. [43° C.] (stream 38c) as it provides cooling as previously described. The residue gas is then re-compressed in two stages, compressor 18 driven by expansion machine 17 and compressor 27 driven by a supplemental power source. After stream 38e is cooled to 120° F. [49° C.] in discharge cooler 28, the residue gas product (stream 38f) flows to the sales gas pipeline at 1040 psia [7,171 kPa(a)].
A summary of stream flow rates and energy consumption for the process illustrated in
A comparison of Tables II and III shows that, compared to the
When the present invention is employed as in Example 2, the advantage with respect to avoiding carbon dioxide icing conditions is maintained compared to the
In accordance with this invention, it is generally advantageous to design the absorbing (rectification) section of the demethanizer to contain multiple theoretical separation stages. However, the benefits of the present invention can be achieved with as few as one theoretical stage, and it is believed that even the equivalent of a fractional theoretical stage may allow achieving these benefits. For instance, all or a part of the expanded substantially condensed distillation stream 43c from expansion valve 25, all or a part of the expanded substantially condensed stream 35b from expansion valve 16, and all or a part of the expanded stream 36a from work expansion machine 17 can be combined (such as in the piping joining the expansion valve to the demethanizer) and if thoroughly intermingled, the vapors and liquids will mix together and separate in accordance with the relative volatilities of the various components of the total combined streams. Such commingling of the three streams shall be considered for the purposes of this invention as constituting an absorbing section.
In some cases it may be advantageous to split the substantially condensed distillation stream 43b into at least two streams as shown in
Feed gas conditions, plant size, available equipment, or other factors may indicate that elimination of work expansion machine 17, or replacement with an alternate expansion device (such as an expansion valve), is feasible. Although individual stream expansion is depicted in particular expansion devices, alternative expansion means may be employed where appropriate. For example, conditions may warrant work expansion of the substantially condensed portion of the feed stream (stream 35a) and/or the substantially condensed distillation stream (stream 43b).
As described in the earlier examples, distillation stream 43 is substantially condensed and the resulting condensate used to absorb valuable C2 components, C3 components, and heavier components from the vapors rising through the upper region of absorbing section 19a of demethanizer 19 (
Under some circumstances, it may be advantageous to heat distillation stream 43 before it is compressed, as this may reduce the capital cost of compressor 21. One means to accomplish this is to use compressed distillation stream 43a (which is warmer due to the heat of compression) to supply this heating using a cross exchanger. In such cases, it may be possible to supplement the cooling of compressed distillation stream 43a by the use of aerial cooling or other means, thereby reducing the cooling that must be supplied in heat exchanger 22 by overhead stream 38. The potential reduction in the capital cost of compressor 21 must be weighed against the capital cost of the additional heating and cooling means for each application to determine whether this embodiment is advantageous.
In accordance with this invention, the splitting of the vapor feed may be accomplished in several ways. In some embodiments, vapor splitting may be effected in a separator. In the processes of
When the inlet gas is leaner, separator 11 in
The high pressure liquid (stream 33) in
In accordance with this invention, the use of external refrigeration to supplement the cooling available to the inlet gas and/or the distillation stream from other process streams may be employed, particularly in the case of a rich inlet gas. The use and distribution of separator liquids and demethanizer side draw liquids for process heat exchange, and the particular arrangement of heat exchangers for inlet gas cooling must be evaluated for each particular application, as well as the choice of process streams for specific heat exchange services.
It will also be recognized that the relative amount of feed found in each branch of the split vapor feed will depend on several factors, including gas pressure, feed gas composition, the amount of heat which can economically be extracted from the feed, and the quantity of horsepower available. More feed to the top of the column may increase recovery while decreasing power recovered from the expander thereby increasing the recompression horsepower requirements. Increasing feed lower in the column reduces the horsepower consumption but may also reduce product recovery. The relative locations of the mid-column feeds may vary depending on inlet composition or other factors such as desired recovery levels and amount of liquid formed during inlet gas cooling. Moreover, two or more of the feed streams, or portions thereof, may be combined depending on the relative temperatures and quantities of individual streams, and the combined stream then fed to a mid-column feed position.
The present invention provides improved recovery of C3 components and heavier hydrocarbon components per amount of utility consumption required to operate the process. An improvement in utility consumption required for operating the demethanizer process may appear in the form of reduced power requirements for compression or re-compression, reduced power requirements for external refrigeration, reduced energy requirements for tower reboilers, or a combination thereof.
While there have been described what are believed to be preferred embodiments of the invention, those skilled in the art will recognize that other and further modifications may be made thereto, e.g. to adapt the invention to various conditions, types of feed, or other requirements without departing from the spirit of the present invention as defined by the following claims.
Claims
1. In a process for the separation of a gas stream containing methane, C2 components, C3 components, and heavier hydrocarbon components into a volatile residue gas fraction and a relatively less volatile fraction containing a major portion of said C2 components, C3 components, and heavier hydrocarbon components or said C3 components and heavier hydrocarbon components, in which process
- (a) said gas stream is cooled under pressure to provide a cooled stream;
- (b) said cooled stream is expanded to a lower pressure whereby it is further cooled; and
- (c) said further cooled stream is directed into a distillation column and fractionated at said lower pressure whereby the components of said relatively less volatile fraction are recovered;
- the improvement wherein following cooling, said cooled stream is divided into first and second streams; and
- (1) said first stream is cooled to condense substantially all of it and is thereafter expanded to said lower pressure whereby it is further cooled;
- (2) said expanded cooled first stream is thereafter supplied at a first mid-column feed position to said distillation column;
- (3) said second stream is expanded to said lower pressure and is supplied to said distillation column at a second mid-column feed position;
- (4) a vapor distillation stream is withdrawn from a region of said distillation column below said expanded second stream and is compressed to higher pressure;
- (5) said compressed vapor distillation stream is cooled sufficiently to condense at least a part of it, thereby forming a condensed stream;
- (6) at least a portion of said condensed stream is expanded to said lower pressure and is thereafter supplied to said distillation column at a top feed position;
- (7) an overhead vapor stream is withdrawn from an upper region of said distillation column and is directed into heat exchange relation with said compressed vapor distillation stream and heated, thereby to supply at least a portion of the cooling of step (5), and thereafter discharging at least a portion of said heated overhead vapor stream as said volatile residue gas fraction; and
- (8) the quantities and temperatures of said feed streams to said distillation column are effective to maintain the overhead temperature of said distillation column at a temperature whereby the major portions of the components in said relatively less volatile fraction are recovered.
2. In a process for the separation of a gas stream containing methane, C2 components, C3 components, and heavier hydrocarbon components into a volatile residue gas fraction and a relatively less volatile fraction containing a major portion of said C2 components, C3 components, and heavier hydrocarbon components or said C3 components and heavier hydrocarbon components, in which process
- (a) said gas stream is cooled under pressure to provide a cooled stream;
- (b) said cooled stream is expanded to a lower pressure whereby it is further cooled; and
- (c) said further cooled stream is directed into a distillation column and fractionated at said lower pressure whereby the components of said relatively less volatile fraction are recovered;
- the improvement wherein prior to cooling, said gas is divided into first and second streams; and
- (1) said first stream is cooled to condense substantially all of it and is thereafter expanded to said lower pressure whereby it is further cooled;
- (2) said expanded cooled first stream is thereafter supplied at a first mid-column feed position to said distillation column;
- (3) said second stream is cooled and thereafter expanded to said lower pressure and supplied to said distillation column at a second mid-column feed position;
- (4) a vapor distillation stream is withdrawn from a region of said distillation column below said expanded cooled second stream and is compressed to higher pressure;
- (5) said compressed vapor distillation stream is cooled sufficiently to condense at least a part of it, thereby forming a condensed stream;
- (6) at least a portion of said condensed stream is expanded to said lower pressure and is thereafter supplied to said distillation column at a top feed position;
- (7) an overhead vapor stream is withdrawn from an upper region of said distillation column and is directed into heat exchange relation with said compressed vapor distillation stream and heated, thereby to supply at least a portion of the cooling of step (5), and thereafter discharging at least a portion of said heated overhead vapor stream as said volatile residue gas fraction; and
- (8) the quantities and temperatures of said feed streams to said distillation column are effective to maintain the overhead temperature of said distillation column at a temperature whereby the major portions of the components in said relatively less volatile fraction are recovered.
3. In a process for the separation of a gas stream containing methane, C2 components, C3 components, and heavier hydrocarbon components into a volatile residue gas fraction and a relatively less volatile fraction containing a major portion of said C2 components, C3 components, and heavier hydrocarbon components or said C3 components and heavier hydrocarbon components, in which process
- (a) said gas stream is cooled under pressure to provide a cooled stream;
- (b) said cooled stream is expanded to a lower pressure whereby it is further cooled; and
- (c) said further cooled stream is directed into a distillation column and fractionated at said lower pressure whereby the components of said relatively less volatile fraction are recovered;
- the improvement wherein said gas stream is cooled sufficiently to partially condense it; and
- (1) said partially condensed gas stream is separated thereby to provide a vapor stream and at least one liquid stream;
- (2) said vapor stream is thereafter divided into first and second streams;
- (3) said first stream is cooled to condense substantially all of it and is thereafter expanded to said lower pressure whereby it is further cooled;
- (4) said expanded cooled first stream is thereafter supplied at a first mid-column feed position to said distillation column;
- (5) said second stream is expanded to said lower pressure and is supplied to said distillation column at a second mid-column feed position;
- (6) at least a portion of said at least one liquid stream is expanded to said lower pressure and is supplied to said distillation column at a third mid-column feed position;
- (7) a vapor distillation stream is withdrawn from a region of said distillation column below said expanded second stream and is compressed to higher pressure;
- (8) said compressed vapor distillation stream is cooled sufficiently to condense at least a part of it, thereby forming a condensed stream;
- (9) at least a portion of said condensed stream is expanded to said lower pressure and is thereafter supplied to said distillation column at a top feed position;
- (10) an overhead vapor stream is withdrawn from an upper region of said distillation column and is directed into heat exchange relation with said compressed vapor distillation stream and heated, thereby to supply at least a portion of the cooling of step (8), and thereafter discharging at least a portion of said heated overhead vapor stream as said volatile residue gas fraction; and
- (11) the quantities and temperatures of said feed streams to said distillation column are effective to maintain the overhead temperature of said distillation column at a temperature whereby the major portions of the components in said relatively less volatile fraction are recovered.
4. In a process for the separation of a gas stream containing methane, C2 components, C3 components, and heavier hydrocarbon components into a volatile residue gas fraction and a relatively less volatile fraction containing a major portion of said C2 components, C3 components, and heavier hydrocarbon components or said C3 components and heavier hydrocarbon components, in which process
- (a) said gas stream is cooled under pressure to provide a cooled stream;
- (b) said cooled stream is expanded to a lower pressure whereby it is further cooled; and
- (c) said further cooled stream is directed into a distillation column and fractionated at said lower pressure whereby the components of said relatively less volatile fraction are recovered;
- the improvement wherein said gas stream is cooled sufficiently to partially condense it; and
- (1) said partially condensed gas stream is separated thereby to provide a vapor stream and at least one liquid stream;
- (2) said vapor stream is thereafter divided into first and second streams;
- (3) said first stream is combined with at least a portion of said at least one liquid stream to form a combined stream, and said combined stream is cooled to condense substantially all of it and is thereafter expanded to said lower pressure whereby it is further cooled;
- (4) said expanded cooled combined stream is thereafter supplied at a first mid-column feed position to said distillation column;
- (5) said second stream is expanded to said lower pressure and is supplied to said distillation column at a second mid-column feed position;
- (6) any remaining portion of said at least one liquid stream is expanded to said lower pressure and is supplied to said distillation column at a third mid-column feed position;
- (7) a vapor distillation stream is withdrawn from a region of said distillation column below said expanded second stream and is compressed to higher pressure;
- (8) said compressed vapor distillation stream is cooled sufficiently to condense at least a part of it, thereby forming a condensed stream;
- (9) at least a portion of said condensed stream is expanded to said lower pressure and is thereafter supplied to said distillation column at a top feed position;
- (10) an overhead vapor stream is withdrawn from an upper region of said distillation column and is directed into heat exchange relation with said compressed vapor distillation stream and heated, thereby to supply at least a portion of the cooling of step (8), and thereafter discharging at least a portion of said heated overhead vapor stream as said volatile residue gas fraction; and
- (11) the quantities and temperatures of said feed streams to said distillation column are effective to maintain the overhead temperature of said distillation column at a temperature whereby the major portions of the components in said relatively less volatile fraction are recovered.
5. In a process for the separation of a gas stream containing methane, C2 components, C3 components, and heavier hydrocarbon components into a volatile residue gas fraction and a relatively less volatile fraction containing a major portion of said C2 components, C3 components, and heavier hydrocarbon components or said C3 components and heavier hydrocarbon components, in which process
- (a) said gas stream is cooled under pressure to provide a cooled stream;
- (b) said cooled stream is expanded to a lower pressure whereby it is further cooled; and
- (c) said further cooled stream is directed into a distillation column and fractionated at said lower pressure whereby the components of said relatively less volatile fraction are recovered;
- the improvement wherein prior to cooling, said gas is divided into first and second streams; and
- (1) said first stream is cooled to condense substantially all of it and is thereafter expanded to said lower pressure whereby it is further cooled;
- (2) said expanded cooled first stream is thereafter supplied at a first mid-column feed position to said distillation column;
- (3) said second stream is cooled under pressure sufficiently to partially condense it;
- (4) said partially condensed second stream is separated thereby to provide a vapor stream and at least one liquid stream;
- (5) said vapor stream is expanded to said lower pressure and supplied to said distillation column at a second mid-column feed position;
- (6) at least a portion of said at least one liquid stream is expanded to said lower pressure and is supplied to said distillation column at a third mid-column feed position;
- (7) a vapor distillation stream is withdrawn from a region of said distillation column below said expanded vapor stream and is compressed to higher pressure;
- (8) said compressed vapor distillation stream is cooled sufficiently to condense at least a part of it, thereby forming a condensed stream;
- (9) at least a portion of said condensed stream is expanded to said lower pressure and is thereafter supplied to said distillation column at a top feed position;
- (10) an overhead vapor stream is withdrawn from an upper region of said distillation column and is directed into heat exchange relation with said compressed vapor distillation stream and heated, thereby to supply at least a portion of the cooling of step (8), and thereafter discharging at least a portion of said heated overhead vapor stream as said volatile residue gas fraction; and
- (11) the quantities and temperatures of said feed streams to said distillation column are effective to maintain the overhead temperature of said distillation column at a temperature whereby the major portions of the components in said relatively less volatile fraction are recovered.
6. In a process for the separation of a gas stream containing methane, C2 components, C3 components, and heavier hydrocarbon components into a volatile residue gas fraction and a relatively less volatile fraction containing a major portion of said C2 components, C3 components, and heavier hydrocarbon components or said C3 components and heavier hydrocarbon components, in which process
- (a) said gas stream is cooled under pressure to provide a cooled stream;
- (b) said cooled stream is expanded to a lower pressure whereby it is further cooled; and
- (c) said further cooled stream is directed into a distillation column and fractionated at said lower pressure whereby the components of said relatively less volatile fraction are recovered;
- the improvement wherein following cooling, said cooled stream is divided into first and second streams; and
- (1) said first stream is cooled to condense substantially all of it and is thereafter expanded to said lower pressure whereby it is further cooled;
- (2) said expanded cooled first stream is thereafter supplied at a mid-column feed position to a contacting and separating device that produces an overhead vapor stream and a bottom liquid stream, whereupon said bottom liquid stream is supplied to said distillation column;
- (3) said second stream is expanded to said lower pressure and is supplied to said contacting and separating device at a first lower feed position;
- (4) a vapor distillation stream is withdrawn from an upper region of said distillation column to form at least a first distillation stream;
- (5) said first distillation stream is compressed to higher pressure;
- (6) said compressed first distillation stream is cooled sufficiently to condense at least a part of it, thereby forming a condensed stream;
- (7) at least a portion of said condensed stream is expanded to said lower pressure and is thereafter supplied to said contacting and separating device at a top feed position;
- (8) any remaining portion of said vapor distillation stream is directed to said contacting and separating device at a second lower feed position;
- (9) said overhead vapor stream is directed into heat exchange relation with said compressed first distillation stream and heated, thereby to supply at least a portion of the cooling of step (6), and thereafter discharging at least a portion of said heated overhead vapor stream as said volatile residue gas fraction; and
- (10) the quantities and temperatures of said feed streams to said contacting and separating device are effective to maintain the overhead temperature of said contacting and separating device at a temperature whereby the major portions of the components in said relatively less volatile fraction are recovered.
7. In a process for the separation of a gas stream containing methane, C2 components, C3 components, and heavier hydrocarbon components into a volatile residue gas fraction and a relatively less volatile fraction containing a major portion of said C2 components, C3 components, and heavier hydrocarbon components or said C3 components and heavier hydrocarbon components, in which process
- (a) said gas stream is cooled under pressure to provide a cooled stream;
- (b) said cooled stream is expanded to a lower pressure whereby it is further cooled; and
- (c) said further cooled stream is directed into a distillation column and fractionated at said lower pressure whereby the components of said relatively less volatile fraction are recovered;
- the improvement wherein prior to cooling, said gas is divided into first and second streams; and
- (1) said first stream is cooled to condense substantially all of it and is thereafter expanded to said lower pressure whereby it is further cooled;
- (2) said expanded cooled first stream is thereafter supplied at a mid-column feed position to a contacting and separating device that produces an overhead vapor stream and a bottom liquid stream, whereupon said bottom liquid stream is supplied to said distillation column;
- (3) said second stream is cooled and thereafter expanded to said lower pressure and is supplied to said contacting and separating device at a first lower feed position;
- (4) a vapor distillation stream is withdrawn from an upper region of said distillation column to form at least a first distillation stream;
- (5) said first distillation stream is compressed to higher pressure;
- (6) said compressed first distillation stream is cooled sufficiently to condense at least a part of it, thereby forming a condensed stream;
- (7) at least a portion of said condensed stream is expanded to said lower pressure and is thereafter supplied to said contacting and separating device at a top feed position;
- (8) any remaining portion of said vapor distillation stream is directed to said contacting and separating device at a second lower feed position;
- (9) said overhead vapor stream is directed into heat exchange relation with said compressed first distillation stream and heated, thereby to supply at least a portion of the cooling of step (6), and thereafter discharging at least a portion of said heated overhead vapor stream as said volatile residue gas fraction; and
- (10) the quantities and temperatures of said feed streams to said contacting and separating device are effective to maintain the overhead temperature of said contacting and separating device at a temperature whereby the major portions of the components in said relatively less volatile fraction are recovered.
8. In a process for the separation of a gas stream containing methane, C2 components, C3 components, and heavier hydrocarbon components into a volatile residue gas fraction and a relatively less volatile fraction containing a major portion of said C2 components, C3 components, and heavier hydrocarbon components or said C3 components and heavier hydrocarbon components, in which process
- (a) said gas stream is cooled under pressure to provide a cooled stream;
- (b) said cooled stream is expanded to a lower pressure whereby it is further cooled; and
- (c) said further cooled stream is directed into a distillation column and fractionated at said lower pressure whereby the components of said relatively less volatile fraction are recovered;
- the improvement wherein said gas stream is cooled sufficiently to partially condense it; and
- (1) said partially condensed gas stream is separated thereby to provide a vapor stream and at least one liquid stream;
- (2) said vapor stream is thereafter divided into first and second streams;
- (3) said first stream is cooled to condense substantially all of it and is thereafter expanded to said lower pressure whereby it is further cooled;
- (4) said expanded cooled first stream is thereafter supplied at a mid-column feed position to a contacting and separating device that produces an overhead vapor stream and a bottom liquid stream, whereupon said bottom liquid stream is supplied to said distillation column;
- (5) said second stream is expanded to said lower pressure and is supplied to said contacting and separating device at a first lower feed position;
- (6) said at least one liquid stream is expanded to said lower pressure and supplied to said distillation column at a mid-column feed position;
- (7) a vapor distillation stream is withdrawn from an upper region of said distillation column to form at least a first distillation stream;
- (8) said first distillation stream is compressed to higher pressure;
- (9) said compressed first distillation stream is cooled sufficiently to condense at least a part of it, thereby forming a condensed stream;
- (10) at least a portion of said condensed stream is expanded to said lower pressure and is thereafter supplied to said contacting and separating device at a top feed position;
- (11) any remaining portion of said vapor distillation stream is directed to said contacting and separating device at a second lower feed position;
- (12) said overhead vapor stream is directed into heat exchange relation with said compressed first distillation stream and heated, thereby to supply at least a portion of the cooling of step (9), and thereafter discharging at least a portion of said heated overhead vapor stream as said volatile residue gas fraction; and
- (13) the quantities and temperatures of said feed streams to said contacting and separating device are effective to maintain the overhead temperature of said contacting and separating device at a temperature whereby the major portions of the components in said relatively less volatile fraction are recovered.
9. In a process for the separation of a gas stream containing methane, C2 components, C3 components, and heavier hydrocarbon components into a volatile residue gas fraction and a relatively less volatile fraction containing a major portion of said C2 components, C3 components, and heavier hydrocarbon components or said C3 components and heavier hydrocarbon components, in which process
- (a) said gas stream is cooled under pressure to provide a cooled stream;
- (b) said cooled stream is expanded to a lower pressure whereby it is further cooled; and
- (c) said further cooled stream is directed into a distillation column and fractionated at said lower pressure whereby the components of said relatively less volatile fraction are recovered;
- the improvement wherein said gas stream is cooled sufficiently to partially condense it; and
- (1) said partially condensed gas stream is separated thereby to provide a vapor stream and at least one liquid stream;
- (2) said vapor stream is thereafter divided into first and second streams;
- (3) said first stream is combined with at least a portion of said at least one liquid stream to form a combined stream, and said combined stream is cooled to condense substantially all of it and is thereafter expanded to said lower pressure whereby it is further cooled;
- (4) said expanded cooled combined stream is thereafter supplied at a mid-column feed position to a contacting and separating device that produces an overhead vapor stream and a bottom liquid stream, whereupon said bottom liquid stream is supplied to said distillation column;
- (5) said second stream is expanded to said lower pressure and is supplied to said contacting and separating device at a first lower feed position;
- (6) any remaining portion of said at least one liquid stream is expanded to said lower pressure and supplied to said distillation column at a mid-column feed position;
- (7) a vapor distillation stream is withdrawn from an upper region of said distillation column to form at least a first distillation stream;
- (8) said first distillation stream is compressed to higher pressure;
- (9) said compressed first distillation stream is cooled sufficiently to condense at least a part of it, thereby forming a condensed stream;
- (10) at least a portion of said condensed stream is expanded to said lower pressure and is thereafter supplied to said contacting and separating device at a top feed position;
- (11) any remaining portion of said vapor distillation stream is directed to said contacting and separating device at a second lower feed position;
- (12) said overhead vapor stream is directed into heat exchange relation with said compressed first distillation stream and heated, thereby to supply at least a portion of the cooling of step (9), and thereafter discharging at least a portion of said heated overhead vapor stream as said volatile residue gas fraction; and
- (13) the quantities and temperatures of said feed streams to said contacting and separating device are effective to maintain the overhead temperature of said contacting and separating device at a temperature whereby the major portions of the components in said relatively less volatile fraction are recovered.
10. In a process for the separation of a gas stream containing methane, C2 components, C3 components, and heavier hydrocarbon components into a volatile residue gas fraction and a relatively less volatile fraction containing a major portion of said C2 components, C3 components, and heavier hydrocarbon components or said C3 components and heavier hydrocarbon components, in which process
- (a) said gas stream is cooled under pressure to provide a cooled stream;
- (b) said cooled stream is expanded to a lower pressure whereby it is further cooled; and
- (c) said further cooled stream is directed into a distillation column and fractionated at said lower pressure whereby the components of said relatively less volatile fraction are recovered;
- the improvement wherein prior to cooling, said gas is divided into first and second streams; and
- (1) said first stream is cooled to condense substantially all of it and is thereafter expanded to said lower pressure whereby it is further cooled;
- (2) said expanded cooled first stream is thereafter supplied at a mid-column feed position to a contacting and separating device that produces an overhead vapor stream and a bottom liquid stream, whereupon said bottom liquid stream is supplied to said distillation column;
- (3) said second stream is cooled under pressure sufficiently to partially condense it;
- (4) said partially condensed second stream is separated thereby to provide a vapor stream and at least one liquid stream;
- (5) said vapor stream is expanded to said lower pressure and is supplied to said contacting and separating device at a first lower feed position;
- (6) said at least one liquid stream is expanded to said lower pressure and supplied to said distillation column at a mid-column feed position;
- (7) a vapor distillation stream is withdrawn from an upper region of said distillation column to form at least a first distillation stream;
- (8) said first distillation stream is compressed to higher pressure;
- (9) said compressed first distillation stream is cooled sufficiently to condense at least a part of it, thereby forming a condensed stream;
- (10) at least a portion of said condensed stream is expanded to said lower pressure and is thereafter supplied to said contacting and separating device at a top feed position;
- (11) any remaining portion of said vapor distillation stream is directed to said contacting and separating device at a second lower feed position;
- (12) said overhead vapor stream is directed into heat exchange relation with said compressed first distillation stream and heated, thereby to supply at least a portion of the cooling of step (9), and thereafter discharging at least a portion of said heated overhead vapor stream as said volatile residue gas fraction; and
- (13) the quantities and temperatures of said feed streams to said contacting and separating device are effective to maintain the overhead temperature of said contacting and separating device at a temperature whereby the major portions of the components in said relatively less volatile fraction are recovered.
11. In a process for the separation of a gas stream containing methane, C2 components, C3 components, and heavier hydrocarbon components into a volatile residue gas fraction and a relatively less volatile fraction containing a major portion of said C2 components, C3 components, and heavier hydrocarbon components or said C3 components and heavier hydrocarbon components, in which process
- (a) said gas stream is cooled under pressure to provide a cooled stream;
- (b) said cooled stream is expanded to a lower pressure whereby it is further cooled; and
- (c) said further cooled stream is directed into a distillation column and fractionated at said lower pressure whereby the components of said relatively less volatile fraction are recovered and a first overhead vapor stream is produced;
- the improvement wherein following cooling, said cooled stream is divided into first and second streams; and
- (1) said first stream is cooled to condense substantially all of it and is thereafter expanded to said lower pressure whereby it is further cooled;
- (2) said expanded cooled first stream is thereafter supplied at a mid-column feed position to a contacting and separating device that produces a second overhead vapor stream and a bottom liquid stream, whereupon said bottom liquid stream is supplied to said distillation column;
- (3) said second stream is expanded to said lower pressure and is supplied to said contacting and separating device at a first lower feed position;
- (4) a vapor distillation stream is withdrawn from a region of said contacting and separating device above said expanded second stream and is compressed to higher pressure;
- (5) said compressed vapor distillation stream is cooled sufficiently to condense at least a part of it, thereby forming a condensed stream;
- (6) at least a portion of said condensed stream is expanded to said lower pressure and is thereafter supplied to said contacting and separating device at a top feed position;
- (7) said first overhead vapor stream is directed to said contacting and separating device at a second lower feed position;
- (8) said second overhead vapor stream is directed into heat exchange relation with said compressed vapor distillation stream and heated, thereby to supply at least a portion of the cooling of step (5), and thereafter discharging at least a portion of said heated second overhead vapor stream as said volatile residue gas fraction; and
- (9) the quantities and temperatures of said feed streams to said contacting and separating device are effective to maintain the overhead temperature of said contacting and separating device at a temperature whereby the major portions of the components in said relatively less volatile fraction are recovered.
12. In a process for the separation of a gas stream containing methane, C2 components, C3 components, and heavier hydrocarbon components into a volatile residue gas fraction and a relatively less volatile fraction containing a major portion of said C2 components, C3 components, and heavier hydrocarbon components or said C3 components and heavier hydrocarbon components, in which process
- (a) said gas stream is cooled under pressure to provide a cooled stream;
- (b) said cooled stream is expanded to a lower pressure whereby it is further cooled; and
- (c) said further cooled stream is directed into a distillation column and fractionated at said lower pressure whereby the components of said relatively less volatile fraction are recovered and a first overhead vapor stream is produced;
- the improvement wherein prior to cooling, said gas is divided into first and second streams; and
- (1) said first stream is cooled to condense substantially all of it and is thereafter expanded to said lower pressure whereby it is further cooled;
- (2) said expanded cooled first stream is thereafter supplied at a mid-column feed position to a contacting and separating device that produces a second overhead vapor stream and a bottom liquid stream, whereupon said bottom liquid stream is supplied to said distillation column;
- (3) said second stream is cooled and thereafter expanded to said lower pressure and is supplied to said contacting and separating device at a first lower feed position;
- (4) a vapor distillation stream is withdrawn from a region of said contacting and separating device above said expanded cooled second stream and is compressed to higher pressure;
- (5) said compressed vapor distillation stream is cooled sufficiently to condense at least a part of it, thereby forming a condensed stream;
- (6) at least a portion of said condensed stream is expanded to said lower pressure and is thereafter supplied to said contacting and separating device at a top feed position;
- (7) said first overhead vapor stream is directed to said contacting and separating device at a second lower feed position;
- (8) said second overhead vapor stream is directed into heat exchange relation with said compressed vapor distillation stream and heated, thereby to supply at least a portion of the cooling of step (5), and thereafter discharging at least a portion of said heated second overhead vapor stream as said volatile residue gas fraction; and
- (9) the quantities and temperatures of said feed streams to said contacting and separating device are effective to maintain the overhead temperature of said contacting and separating device at a temperature whereby the major portions of the components in said relatively less volatile fraction are recovered.
13. In a process for the separation of a gas stream containing methane, C2 components, C3 components, and heavier hydrocarbon components into a volatile residue gas fraction and a relatively less volatile fraction containing a major portion of said C2 components, C3 components, and heavier hydrocarbon components or said C3 components and heavier hydrocarbon components, in which process
- (a) said gas stream is cooled under pressure to provide a cooled stream;
- (b) said cooled stream is expanded to a lower pressure whereby it is further cooled; and
- (c) said further cooled stream is directed into a distillation column and fractionated at said lower pressure whereby the components of said relatively less volatile fraction are recovered and a first overhead vapor stream is produced;
- the improvement wherein said gas stream is cooled sufficiently to partially condense it; and
- (1) said partially condensed gas stream is separated thereby to provide a vapor stream and at least one liquid stream;
- (2) said vapor stream is thereafter divided into first and second streams;
- (3) said first stream is cooled to condense substantially all of it and is thereafter expanded to said lower pressure whereby it is further cooled;
- (4) said expanded cooled first stream is thereafter supplied at a mid-column feed position to a contacting and separating device that produces a second overhead vapor stream and a bottom liquid stream, whereupon said bottom liquid stream is supplied to said distillation column;
- (5) said second stream is expanded to said lower pressure and is supplied to said contacting and separating device at a first lower feed position;
- (6) said at least one liquid stream is expanded to said lower pressure and supplied to said distillation column at a mid-column feed position;
- (7) a vapor distillation stream is withdrawn from a region of said contacting and separating device above said expanded second stream and is compressed to higher pressure;
- (8) said compressed vapor distillation stream is cooled sufficiently to condense at least a part of it, thereby forming a condensed stream;
- (9) at least a portion of said condensed stream is expanded to said lower pressure and is thereafter supplied to said contacting and separating device at a top feed position;
- (10) said first overhead stream is directed to said contacting and separating device at a second lower feed position;
- (11) said second overhead vapor stream is directed into heat exchange relation with said compressed vapor distillation stream and heated, thereby to supply at least a portion of the cooling of step (8), and thereafter discharging at least a portion of said heated second overhead vapor stream as said volatile residue gas fraction; and
- (12) the quantities and temperatures of said feed streams to said contacting and separating device are effective to maintain the overhead temperature of said contacting and separating device at a temperature whereby the major portions of the components in said relatively less volatile fraction are recovered.
14. In a process for the separation of a gas stream containing methane, C2 components, C3 components, and heavier hydrocarbon components into a volatile residue gas fraction and a relatively less volatile fraction containing a major portion of said C2 components, C3 components, and heavier hydrocarbon components or said C3 components and heavier hydrocarbon components, in which process
- (a) said gas stream is cooled under pressure to provide a cooled stream;
- (b) said cooled stream is expanded to a lower pressure whereby it is further cooled; and
- (c) said further cooled stream is directed into a distillation column and fractionated at said lower pressure whereby the components of said relatively less volatile fraction are recovered and a first overhead vapor stream is produced;
- the improvement wherein said gas stream is cooled sufficiently to partially condense it; and
- (1) said partially condensed gas stream is separated thereby to provide a vapor stream and at least one liquid stream;
- (2) said vapor stream is thereafter divided into first and second streams;
- (3) said first stream is combined with at least a portion of said at least one liquid stream to form a combined stream, and said combined stream is cooled to condense substantially all of it and is thereafter expanded to said lower pressure whereby it is further cooled;
- (4) said expanded cooled combined stream is thereafter supplied at a mid-column feed position to a contacting and separating device that produces a second overhead vapor stream and a bottom liquid stream, whereupon said bottom liquid stream is supplied to said distillation column;
- (5) said second stream is expanded to said lower pressure and is supplied to said contacting and separating device at a first lower feed position;
- (6) any remaining portion of said at least one liquid stream is expanded to said lower pressure and supplied to said distillation column at a mid-column feed position;
- (7) a vapor distillation stream is withdrawn from a region of said contacting and separating device above said expanded second stream and is compressed to higher pressure;
- (8) said compressed vapor distillation stream is cooled sufficiently to condense at least a part of it, thereby forming a condensed stream;
- (9) at least a portion of said condensed stream is expanded to said lower pressure and is thereafter supplied to said contacting and separating device at a top feed position;
- (10) said first overhead stream is directed to said contacting and separating device at a second lower feed position;
- (11) said second overhead vapor stream is directed into heat exchange relation with said compressed vapor distillation stream and heated, thereby to supply at least a portion of the cooling of step (8), and thereafter discharging at least a portion of said heated second overhead vapor stream as said volatile residue gas fraction; and
- (12) the quantities and temperatures of said feed streams to said contacting and separating device are effective to maintain the overhead temperature of said contacting and separating device at a temperature whereby the major portions of the components in said relatively less volatile fraction are recovered.
15. In a process for the separation of a gas stream containing methane, C2 components, C3 components, and heavier hydrocarbon components into a volatile residue gas fraction and a relatively less volatile fraction containing a major portion of said C2 components, C3 components, and heavier hydrocarbon components or said C3 components and heavier hydrocarbon components, in which process
- (a) said gas stream is cooled under pressure to provide a cooled stream;
- (b) said cooled stream is expanded to a lower pressure whereby it is further cooled; and
- (c) said further cooled stream is directed into a distillation column and fractionated at said lower pressure whereby the components of said relatively less volatile fraction are recovered and a first overhead vapor stream is produced;
- the improvement wherein prior to cooling, said gas is divided into first and second streams; and
- (1) said first stream is cooled to condense substantially all of it and is thereafter expanded to said lower pressure whereby it is further cooled;
- (2) said expanded cooled first stream is thereafter supplied at a mid-column feed position to a contacting and separating device that produces a second overhead vapor stream and a bottom liquid stream, whereupon said bottom liquid stream is supplied to said distillation column;
- (3) said second stream is cooled under pressure sufficiently to partially condense it;
- (4) said partially condensed second stream is separated thereby to provide a vapor stream and at least one liquid stream;
- (5) said vapor stream is expanded to said lower pressure and is supplied to said contacting and separating device at a first lower feed position;
- (6) said at least one liquid stream is expanded to said lower pressure and supplied to said distillation column at a mid-column feed position;
- (7) a vapor distillation stream is withdrawn from a region of said contacting and separating device above said expanded vapor stream and is compressed to higher pressure;
- (8) said compressed vapor distillation stream is cooled sufficiently to condense at least a part of it, thereby forming a condensed stream;
- (9) at least a portion of said condensed stream is expanded to said lower pressure and is thereafter supplied to said contacting and separating device at a top feed position;
- (10) said first overhead stream is directed to said contacting and separating device at a second lower feed position;
- (11) said second overhead vapor stream is directed into heat exchange relation with said compressed vapor distillation stream and heated, thereby to supply at least a portion of the cooling of step (8), and thereafter discharging at least a portion of said heated second overhead vapor stream as said volatile residue gas fraction; and
- (12) the quantities and temperatures of said feed streams to said contacting and separating device are effective to maintain the overhead temperature of said contacting and separating device at a temperature whereby the major portions of the components in said relatively less volatile fraction are recovered.
16. The improvement according to claim 1, 3, or 4 wherein said vapor distillation stream is withdrawn from a region of said distillation column above said expanded second stream and is thereafter compressed to higher pressure.
17. The improvement according to claim 2 wherein said vapor distillation stream is withdrawn from a region of said distillation column above said expanded cooled second stream and is thereafter compressed to higher pressure.
18. The improvement according to claim 5 wherein said vapor distillation stream is withdrawn from a region of said distillation column above said expanded vapor stream and is thereafter compressed to higher pressure.
19. The improvement according to claim 1, 3, or 4 wherein
- (1) said condensed stream is divided into at least a first portion and a second portion;
- (2) said first portion is expanded to said lower pressure and is thereafter supplied to said distillation column at said top feed position; and
- (3) said second portion is expanded to said lower pressure and is thereafter supplied to said distillation column at a mid-column feed position above that of said expanded second stream.
20. The improvement according to claim 2 wherein
- (1) said condensed stream is divided into at least a first portion and a second portion;
- (2) said first portion is expanded to said lower pressure and is thereafter supplied to said distillation column at said top feed position; and
- (3) said second portion is expanded to said lower pressure and is thereafter supplied to said distillation column at a mid-column feed position above that of said expanded cooled second stream.
21. The improvement according to claim 5 wherein
- (1) said condensed stream is divided into at least a first portion and a second portion;
- (2) said first portion is expanded to said lower pressure and is thereafter supplied to said distillation column at said top feed position; and
- (3) said second portion is expanded to said lower pressure and is thereafter supplied to said distillation column at a mid-column feed position above that of said expanded vapor stream.
22. The improvement according to claim 6, 8, or 9 wherein
- (1) said condensed stream is divided into at least a first portion and a second portion;
- (2) said first portion is expanded to said lower pressure and is thereafter supplied to said contacting and separating device at said top feed position; and
- (3) said second portion is expanded to said lower pressure and is thereafter supplied to said contacting and separating device at a mid-column feed position above that of said expanded second stream.
23. The improvement according to claim 7 wherein
- (1) said condensed stream is divided into at least a first portion and a second portion;
- (2) said first portion is expanded to said lower pressure and is thereafter supplied to said contacting and separating device at said top feed position; and
- (3) said second portion is expanded to said lower pressure and is thereafter supplied to said contacting and separating device at a mid-column feed position above that of said expanded cooled second stream.
24. The improvement according to claim 10 wherein
- (1) said condensed stream is divided into at least a first portion and a second portion;
- (2) said first portion is expanded to said lower pressure and is thereafter supplied to said contacting and separating device at said top feed position; and
- (3) said second portion is expanded to said lower pressure and is thereafter supplied to said contacting and separating device at a mid-column feed position above that of said expanded vapor stream.
25. The improvement according to claim 11, 12, 13, 14, or 15 wherein
- (1) said condensed stream is divided into at least a first portion and a second portion;
- (2) said first portion is expanded to said lower pressure and is thereafter supplied to said contacting and separating device at said top feed position; and
- (3) said second portion is expanded to said lower pressure and is thereafter supplied to said contacting and separating device at a mid-column feed position above the region wherein said vapor distillation stream is withdrawn.
26. The improvement according to claim 16 wherein
- (1) said condensed stream is divided into at least a first portion and a second portion;
- (2) said first portion is expanded to said lower pressure and is thereafter supplied to said distillation column at said top feed position; and
- (3) said second portion is expanded to said lower pressure and is thereafter supplied to said distillation column at a mid-column feed position above the region wherein said vapor distillation stream is withdrawn.
27. The improvement according to claim 17 or 18 wherein
- (1) said condensed stream is divided into at least a first portion and a second portion;
- (2) said first portion is expanded to said lower pressure and is thereafter supplied to said distillation column at said top feed position; and
- (3) said second portion is expanded to said lower pressure and is thereafter supplied to said distillation column at a mid-column feed position above the region wherein said vapor distillation stream is withdrawn.
28. In an apparatus for the separation of a gas stream containing methane, C2 components, C3 components, and heavier hydrocarbon components into a volatile residue gas fraction and a relatively less volatile fraction containing a major portion of said C2 components, C3 components, and heavier hydrocarbon components or said C3 components and heavier hydrocarbon components, in said apparatus there being
- (a) a first cooling means to cool said gas under pressure connected to provide a cooled stream under pressure;
- (b) a first expansion means connected to receive at least a portion of said cooled stream under pressure and to expand it to a lower pressure, whereby said stream is further cooled; and
- (c) a distillation column connected to receive said further cooled stream, said distillation column being adapted to separate said further cooled stream into an overhead vapor stream and said relatively less volatile fraction;
- the improvement wherein said apparatus includes
- (1) dividing means connected to said first cooling means to receive said cooled stream and to divide it into first and second streams;
- (2) second cooling means connected to said dividing means to receive said first stream and to cool it sufficiently to substantially condense it;
- (3) second expansion means connected to said second cooling means to receive said substantially condensed first stream and to expand it to said lower pressure, said second expansion means being further connected to said distillation column to supply said expanded cooled first stream to said distillation column at a first mid-column feed position;
- (4) said first expansion means being connected to said dividing means to receive said second stream and to expand it to said lower pressure, said first expansion means being further connected to said distillation column to supply said expanded second stream to said distillation column at a second mid-column feed position;
- (5) vapor withdrawing means connected to said distillation column to receive a vapor distillation stream from a region of said distillation column below said expanded second stream;
- (6) compressing means connected to said vapor withdrawing means to receive said vapor distillation stream and to compress it to higher pressure;
- (7) heat exchange means connected to said compressing means to receive said compressed vapor distillation stream and to cool it sufficiently to condense at least a part of it, thereby forming a condensed stream;
- (8) third expansion means connected to said heat exchange means to receive at least a portion of said condensed stream and to expand it to said lower pressure, said third expansion means being further connected to said distillation column to supply said at least a portion of said expanded condensed stream to said distillation column at a top feed position;
- (9) said distillation column being further connected to said heat exchange means to direct at least a portion of said overhead vapor stream separated therein into heat exchange relation with said compressed vapor distillation stream and to heat said overhead vapor stream, thereby to supply at least a portion of the cooling of step (7), and thereafter discharging at least a portion of said heated overhead vapor stream as said volatile residue gas fraction; and
- (10) control means adapted to regulate the quantities and temperatures of said feed streams to said distillation column to maintain the overhead temperature of said distillation column at a temperature whereby the major portions of the components in said relatively less volatile fraction are recovered.
29. In an apparatus for the separation of a gas stream containing methane, C2 components, C3 components, and heavier hydrocarbon components into a volatile residue gas fraction and a relatively less volatile fraction containing a major portion of said C2 components, C3 components, and heavier hydrocarbon components or said C3 components and heavier hydrocarbon components, in said apparatus there being
- (a) a first cooling means to cool said gas under pressure connected to provide a cooled stream under pressure;
- (b) a first expansion means connected to receive at least a portion of said cooled stream under pressure and to expand it to a lower pressure, whereby said stream is further cooled; and
- (c) a distillation column connected to receive said further cooled stream, said distillation column being adapted to separate said further cooled stream into an overhead vapor stream and said relatively less volatile fraction;
- the improvement wherein said apparatus includes
- (1) dividing means prior to said first cooling means to divide said feed gas into first and second streams;
- (2) second cooling means connected to said dividing means to receive said first stream and to cool it sufficiently to substantially condense it;
- (3) second expansion means connected to said second cooling means to receive said substantially condensed first stream and to expand it to said lower pressure, said second expansion means being further connected to said distillation column to supply said expanded cooled first stream to said distillation column at a first mid-column feed position;
- (4) said first cooling means being connected to said dividing means to receive said second stream and to cool it;
- (5) said first expansion means being connected to said first cooling means to receive said cooled second stream and to expand it to said lower pressure, said first expansion means being further connected to said distillation column to supply said expanded cooled second stream to said distillation column at a second mid-column feed position;
- (6) vapor withdrawing means connected to said distillation column to receive a vapor distillation stream from a region of said distillation column below said expanded cooled second stream;
- (7) compressing means connected to said vapor withdrawing means to receive said vapor distillation stream and to compress it to higher pressure;
- (8) heat exchange means connected to said compressing means to receive said compressed vapor distillation stream and to cool it sufficiently to condense at least a part of it, thereby forming a condensed stream;
- (9) third expansion means connected to said heat exchange means to receive at least a portion of said condensed stream and to expand it to said lower pressure, said third expansion means being further connected to said distillation column to supply said at least a portion of said expanded condensed stream to said distillation column at a top feed position;
- (10) said distillation column being further connected to said heat exchange means to direct at least a portion of said overhead vapor stream separated therein into heat exchange relation with said compressed vapor distillation stream and to heat said overhead vapor stream, thereby to supply at least a portion of the cooling of step (8), and thereafter discharging at least a portion of said heated overhead vapor stream as said volatile residue gas fraction; and
- (11) control means adapted to regulate the quantities and temperatures of said feed streams to said distillation column to maintain the overhead temperature of said distillation column at a temperature whereby the major portions of the components in said relatively less volatile fraction are recovered.
30. In an apparatus for the separation of a gas stream containing methane, C2 components, C3 components, and heavier hydrocarbon components into a volatile residue gas fraction and a relatively less volatile fraction containing a major portion of said C2 components, C3 components, and heavier hydrocarbon components or said C3 components and heavier hydrocarbon components, in said apparatus there being
- (a) a first cooling means to cool said gas under pressure connected to provide a cooled stream under pressure;
- (b) a first expansion means connected to receive at least a portion of said cooled stream under pressure and to expand it to a lower pressure, whereby said stream is further cooled; and
- (c) a distillation column connected to receive said further cooled stream, said distillation column being adapted to separate said further cooled stream into an overhead vapor stream and said relatively less volatile fraction;
- the improvement wherein said apparatus includes
- (1) said first cooling means being adapted to cool said feed gas under pressure sufficiently to partially condense it;
- (2) separating means connected to said first cooling means to receive said partially condensed feed and to separate it into a vapor stream and at least one liquid stream;
- (3) dividing means connected to said separating means to receive said vapor stream and to divide it into first and second streams;
- (4) second cooling means connected to said dividing means to receive said first stream and to cool it sufficiently to substantially condense it;
- (5) second expansion means connected to said second cooling means to receive said substantially condensed first stream and to expand it to said lower pressure, said second expansion means being further connected to said distillation column to supply said expanded cooled first stream to said distillation column at a first mid-column feed position;
- (6) said first expansion means being connected to said dividing means to receive said second stream and to expand it to said lower pressure, said first expansion means being further connected to said distillation column to supply said expanded second stream to said distillation column at a second mid-column feed position;
- (7) third expansion means connected to said separating means to receive at least a portion of said at least one liquid stream and to expand it to said lower pressure, said third expansion means being further connected to said distillation column to supply said expanded liquid stream to said distillation column at a third mid-column feed position;
- (8) vapor withdrawing means connected to said distillation column to receive a vapor distillation stream from a region of said distillation column below said expanded second stream;
- (9) compressing means connected to said vapor withdrawing means to receive said vapor distillation stream and to compress it to higher pressure;
- (10) heat exchange means connected to said compressing means to receive said compressed vapor distillation stream and to cool it sufficiently to condense at least a part of it, thereby forming a condensed stream;
- (11) fourth expansion means connected to said heat exchange means to receive at least a portion of said condensed stream and to expand it to said lower pressure, said fourth expansion means being further connected to said distillation column to supply said at least a portion of said expanded condensed stream to said distillation column at a top feed position;
- (12) said distillation column being further connected to said heat exchange means to direct at least a portion of said overhead vapor stream separated therein into heat exchange relation with said compressed vapor distillation stream and to heat said overhead vapor stream, thereby to supply at least a portion of the cooling of step (10), and thereafter discharging at least a portion of said heated overhead vapor stream as said volatile residue gas fraction; and
- (13) control means adapted to regulate the quantities and temperatures of said feed streams to said distillation column to maintain the overhead temperature of said distillation column at a temperature whereby the major portions of the components in said relatively less volatile fraction are recovered.
31. In an apparatus for the separation of a gas stream containing methane, C2 components, C3 components, and heavier hydrocarbon components into a volatile residue gas fraction and a relatively less volatile fraction containing a major portion of said C2 components, C3 components, and heavier hydrocarbon components or said C3 components and heavier hydrocarbon components, in said apparatus there being
- (a) a first cooling means to cool said gas under pressure connected to provide a cooled stream under pressure;
- (b) a first expansion means connected to receive at least a portion of said cooled stream under pressure and to expand it to a lower pressure, whereby said stream is further cooled; and
- (c) a distillation column connected to receive said further cooled stream, said distillation column being adapted to separate said further cooled stream into an overhead vapor stream and said relatively less volatile fraction;
- the improvement wherein said apparatus includes
- (1) said first cooling means being adapted to cool said feed gas under pressure sufficiently to partially condense it;
- (2) separating means connected to said first cooling means to receive said partially condensed feed and to separate it into a vapor stream and at least one liquid stream;
- (3) dividing means connected to said separating means to receive said vapor stream and to divide it into first and second streams;
- (4) combining means connected to said dividing means and said separating means to receive said first stream and at least a portion of said at least one liquid stream and form a combined stream;
- (5) second cooling means connected to said combining means to receive said combined stream and to cool it sufficiently to substantially condense it;
- (6) second expansion means connected to said second cooling means to receive said substantially condensed combined stream and to expand it to said lower pressure, said second expansion means being further connected to said distillation column to supply said expanded cooled combined stream to said distillation column at a first mid-column feed position;
- (7) said first expansion means being connected to said dividing means to receive said second stream and to expand it to said lower pressure, said first expansion means being further connected to said distillation column to supply said expanded second stream to said distillation column at a second mid-column feed position;
- (8) third expansion means connected to said separating means to receive any remaining portion of said at least one liquid stream and to expand it to said lower pressure, said third expansion means being further connected to said distillation column to supply said expanded liquid stream to said distillation column at a third mid-column feed position;
- (9) vapor withdrawing means connected to said distillation column to receive a vapor distillation stream from a region of said distillation column below said expanded second stream;
- (10) compressing means connected to said vapor withdrawing means to receive said vapor distillation stream and to compress it to higher pressure;
- (11) heat exchange means connected to said compressing means to receive said compressed vapor distillation stream and to cool it sufficiently to condense at least a part of it, thereby forming a condensed stream;
- (12) fourth expansion means connected to said heat exchange means to receive at least a portion of said condensed stream and to expand it to said lower pressure, said fourth expansion means being further connected to said distillation column to supply said at least a portion of said expanded condensed stream to said distillation column at a top feed position;
- (13) said distillation column being further connected to said heat exchange means to direct at least a portion of said overhead vapor stream separated therein into heat exchange relation with said compressed vapor distillation stream and to heat said overhead vapor stream, thereby to supply at least a portion of the cooling of step (11), and thereafter discharging at least a portion of said heated overhead vapor stream as said volatile residue gas fraction; and
- (14) control means adapted to regulate the quantities and temperatures of said feed streams to said distillation column to maintain the overhead temperature of said distillation column at a temperature whereby the major portions of the components in said relatively less volatile fraction are recovered.
32. In an apparatus for the separation of a gas stream containing methane, C2 components, C3 components, and heavier hydrocarbon components into a volatile residue gas fraction and a relatively less volatile fraction containing a major portion of said C2 components, C3 components, and heavier hydrocarbon components or said C3 components and heavier hydrocarbon components, in said apparatus there being
- (a) a first cooling means to cool said gas under pressure connected to provide a cooled stream under pressure;
- (b) a first expansion means connected to receive at least a portion of said cooled stream under pressure and to expand it to a lower pressure, whereby said stream is further cooled; and
- (c) a distillation column connected to receive said further cooled stream, said distillation column being adapted to separate said further cooled stream into an overhead vapor stream and said relatively less volatile fraction;
- the improvement wherein said apparatus includes
- (1) dividing means prior to said first cooling means to divide said feed gas into first and second streams;
- (2) second cooling means connected to said dividing means to receive said first stream and to cool it sufficiently to substantially condense it;
- (3) second expansion means connected to said second cooling means to receive said substantially condensed first stream and to expand it to said lower pressure, said second expansion means being further connected to said distillation column to supply said expanded cooled first stream to said distillation column at a first mid-column feed position;
- (4) said first cooling means being connected to said dividing means to receive said second stream, said first cooling means being adapted to cool said second stream under pressure sufficiently to partially condense it;
- (5) separating means connected to said first cooling means to receive said partially condensed second stream and to separate it into a vapor stream and at least one liquid stream;
- (6) said first expansion means being connected to said separating means to receive said vapor stream and to expand it to said lower pressure, said first expansion means being further connected to said distillation column to supply said expanded vapor stream to said distillation column at a second mid-column feed position;
- (7) third expansion means connected to said separating means to receive at least a portion of said at least one liquid stream and to expand it to said lower pressure, said third expansion means being further connected to said distillation column to supply said expanded liquid stream to said distillation column at a third mid-column feed position;
- (8) vapor withdrawing means connected to said distillation column to receive a vapor distillation stream from a region of said distillation column below said expanded vapor stream;
- (9) compressing means connected to said vapor withdrawing means to receive said vapor distillation stream and to compress it to higher pressure;
- (10) heat exchange means connected to said compressing means to receive said compressed vapor distillation stream and to cool it sufficiently to condense at least a part of it, thereby forming a condensed stream;
- (11) fourth expansion means connected to said heat exchange means to receive at least a portion of said condensed stream and to expand it to said lower pressure, said fourth expansion means being further connected to said distillation column to supply said at least a portion of said expanded condensed stream to said distillation column at a top feed position;
- (12) said distillation column being further connected to said heat exchange means to direct at least a portion of said overhead vapor stream separated therein into heat exchange relation with said compressed vapor distillation stream and to heat said overhead vapor stream, thereby to supply at least a portion of the cooling of step (10), and thereafter discharging at least a portion of said heated overhead vapor stream as said volatile residue gas fraction; and
- (13) control means adapted to regulate the quantities and temperatures of said feed streams to said distillation column to maintain the overhead temperature of said distillation column at a temperature whereby the major portions of the components in said relatively less volatile fraction are recovered.
33. In an apparatus for the separation of a gas stream containing methane, C2 components, C3 components, and heavier hydrocarbon components into a volatile residue gas fraction and a relatively less volatile fraction containing a major portion of said C2 components, C3 components, and heavier hydrocarbon components or said C3 components and heavier hydrocarbon components, in said apparatus there being
- (a) a first cooling means to cool said gas under pressure connected to provide a cooled stream under pressure;
- (b) a first expansion means connected to receive at least a portion of said cooled stream under pressure and to expand it to a lower pressure, whereby said stream is further cooled; and
- (c) a distillation column connected to receive said further cooled stream, said distillation column being adapted to separate said further cooled stream into a vapor distillation stream and said relatively less volatile fraction;
- the improvement wherein said apparatus includes
- (1) dividing means connected to said first cooling means to receive said cooled stream and to divide it into first and second streams;
- (2) second cooling means connected to said dividing means to receive said first stream and to cool it sufficiently to substantially condense it;
- (3) second expansion means connected to said second cooling means to receive said substantially condensed first stream and to expand it to said lower pressure, said second expansion means being further connected to a contacting and separating means to supply said expanded cooled first stream to said contacting and separating means at a mid-column feed position, said contacting and separating means being adapted to produce an overhead vapor stream and a bottom liquid stream;
- (4) said first expansion means being connected to said dividing means to receive said second stream and to expand it to said lower pressure, said first expansion means being further connected to said contacting and separating means to supply said expanded second stream to said contacting and separating means at a first lower feed position;
- (5) said distillation column being connected to said contacting and separating means to receive at least a portion of said bottom liquid stream;
- (6) vapor withdrawing means connected to said distillation column to receive said vapor distillation stream and form at least a first distillation stream;
- (7) compressing means connected to said vapor withdrawing means to receive said first distillation stream and to compress it to higher pressure;
- (8) heat exchange means connected to said compressing means to receive said compressed first distillation stream and to cool it sufficiently to condense at least a part of it, thereby forming a condensed stream;
- (9) third expansion means connected to said heat exchange means to receive at least a portion of said condensed stream and to expand it to said lower pressure, said third expansion means being further connected to said contacting and separating means to supply said at least a portion of said expanded condensed stream to said contacting and separating means at a top feed position;
- (10) said vapor withdrawing means being further connected to said contacting and separating means to direct any remaining portion of said vapor distillation stream to said contacting and separating means at a second lower feed position;
- (11) said contacting and separating means being further connected to said heat exchange means to direct at least a portion of said overhead vapor stream separated therein into heat exchange relation with said compressed first distillation stream and to heat said overhead vapor stream, thereby to supply at least a portion of the cooling of step (8), and thereafter discharging at least a portion of said heated overhead vapor stream as said volatile residue gas fraction; and
- (12) control means adapted to regulate the quantities and temperatures of said feed streams to said contacting and separating means to maintain the overhead temperature of said contacting and separating means at a temperature whereby the major portions of the components in said relatively less volatile fraction are recovered.
34. In an apparatus for the separation of a gas stream containing methane, C2 components, C3 components, and heavier hydrocarbon components into a volatile residue gas fraction and a relatively less volatile fraction containing a major portion of said C2 components, C3 components, and heavier hydrocarbon components or said C3 components and heavier hydrocarbon components, in said apparatus there being
- (a) a first cooling means to cool said gas under pressure connected to provide a cooled stream under pressure;
- (b) a first expansion means connected to receive at least a portion of said cooled stream under pressure and to expand it to a lower pressure, whereby said stream is further cooled; and
- (c) a distillation column connected to receive said further cooled stream, said distillation column being adapted to separate said further cooled stream into a vapor distillation stream and said relatively less volatile fraction;
- the improvement wherein said apparatus includes
- (1) dividing means prior to said first cooling means to divide said feed gas into first and second streams;
- (2) second cooling means connected to said dividing means to receive said first stream and to cool it sufficiently to substantially condense it;
- (3) second expansion means connected to said second cooling means to receive said substantially condensed first stream and to expand it to said lower pressure, said second expansion means being further connected to a contacting and separating means to supply said expanded cooled first stream to said contacting and separating means at a mid-column feed position, said contacting and separating means being adapted to produce an overhead vapor stream and a bottom liquid stream;
- (4) said first cooling means being connected to said dividing means to receive said second stream and to cool it;
- (5) said first expansion means being connected to said first cooling means to receive said cooled second stream and to expand it to said lower pressure, said first expansion means being further connected to said contacting and separating means to supply said expanded cooled second stream to said contacting and separating means at a first lower feed position;
- (6) said distillation column being connected to said contacting and separating means to receive at least a portion of said bottom liquid stream;
- (7) vapor withdrawing means connected to said distillation column to receive said vapor distillation stream and form at least a first distillation stream;
- (8) compressing means connected to said vapor withdrawing means to receive said first distillation stream and to compress it to higher pressure;
- (9) heat exchange means connected to said compressing means to receive said compressed first distillation stream and to cool it sufficiently to condense at least a part of it, thereby forming a condensed stream;
- (10) third expansion means connected to said heat exchange means to receive at least a portion of said condensed stream and to expand it to said lower pressure, said third expansion means being further connected to said contacting and separating means to supply said at least a portion of said expanded condensed stream to said contacting and separating means at a top feed position;
- (11) said vapor withdrawing means being further connected to said contacting and separating means to direct any remaining portion of said vapor distillation stream to said contacting and separating means at a second lower feed position;
- (12) said contacting and separating means being further connected to said heat exchange means to direct at least a portion of said overhead vapor stream separated therein into heat exchange relation with said compressed first distillation stream and to heat said overhead vapor stream, thereby to supply at least a portion of the cooling of step (9), and thereafter discharging at least a portion of said heated overhead vapor stream as said volatile residue gas fraction; and
- (13) control means adapted to regulate the quantities and temperatures of said feed streams to said contacting and separating means to maintain the overhead temperature of said contacting and separating means at a temperature whereby the major portions of the components in said relatively less volatile fraction are recovered.
35. In an apparatus for the separation of a gas stream containing methane, C2 components, C3 components, and heavier hydrocarbon components into a volatile residue gas fraction and a relatively less volatile fraction containing a major portion of said C2 components, C3 components, and heavier hydrocarbon components or said C3 components and heavier hydrocarbon components, in said apparatus there being
- (a) a first cooling means to cool said gas under pressure connected to provide a cooled stream under pressure;
- (b) a first expansion means connected to receive at least a portion of said cooled stream under pressure and to expand it to a lower pressure, whereby said stream is further cooled; and
- (c) a distillation column connected to receive said further cooled stream, said distillation column being adapted to separate said further cooled stream into a vapor distillation stream and said relatively less volatile fraction;
- the improvement wherein said apparatus includes
- (1) said first cooling means being adapted to cool said feed gas under pressure sufficiently to partially condense it;
- (2) separating means connected to said first cooling means to receive said partially condensed feed and to separate it into a vapor stream and at least one liquid stream;
- (3) dividing means connected to said separating means to receive said vapor stream and to divide it into first and second streams;
- (4) second cooling means connected to said dividing means to receive said first stream and to cool it sufficiently to substantially condense it;
- (5) second expansion means connected to said second cooling means to receive said substantially condensed first stream and to expand it to said lower pressure, said second expansion means being further connected to a contacting and separating means to supply said expanded cooled first stream to said contacting and separating means at a mid-column feed position, said contacting and separating means being adapted to produce an overhead vapor stream and a bottom liquid stream;
- (6) said first expansion means being connected to said dividing means to receive said second stream and to expand it to said lower pressure, said first expansion means being further connected to said contacting and separating means to supply said expanded second stream to said contacting and separating means at a first lower feed position;
- (7) said distillation column being connected to said contacting and separating means to receive at least a portion of said bottom liquid stream;
- (8) third expansion means connected to said separating means to receive at least a portion of said at least one liquid stream and to expand it to said lower pressure, said third expansion means being further connected to said distillation column to supply said expanded liquid stream to said distillation column at a mid-column feed position;
- (9) vapor withdrawing means connected to said distillation column to receive said vapor distillation stream and form at least a first distillation stream;
- (10) compressing means connected to said vapor withdrawing means to receive said first distillation stream and to compress it to higher pressure;
- (11) heat exchange means connected to said compressing means to receive said compressed first distillation stream and to cool it sufficiently to condense at least a part of it, thereby forming a condensed stream;
- (12) fourth expansion means connected to said heat exchange means to receive at least a portion of said condensed stream and to expand it to said lower pressure, said fourth expansion means being further connected to said contacting and separating means to supply said at least a portion of said expanded condensed stream to said contacting and separating means at a top feed position;
- (13) said vapor withdrawing means being further connected to said contacting and separating means to direct any remaining portion of said vapor distillation stream to said contacting and separating means at a second lower feed position;
- (14) said contacting and separating means being further connected to said heat exchange means to direct at least a portion of said overhead vapor stream separated therein into heat exchange relation with said compressed first distillation stream and to heat said overhead vapor stream, thereby to supply at least a portion of the cooling of step (11), and thereafter discharging at least a portion of said heated overhead vapor stream as said volatile residue gas fraction; and
- (15) control means adapted to regulate the quantities and temperatures of said feed streams to said contacting and separating means to maintain the overhead temperature of said contacting and separating means at a temperature whereby the major portions of the components in said relatively less volatile fraction are recovered.
36. In an apparatus for the separation of a gas stream containing methane, C2 components, C3 components, and heavier hydrocarbon components into a volatile residue gas fraction and a relatively less volatile fraction containing a major portion of said C2 components, C3 components, and heavier hydrocarbon components or said C3 components and heavier hydrocarbon components, in said apparatus there being
- (a) a first cooling means to cool said gas under pressure connected to provide a cooled stream under pressure;
- (b) a first expansion means connected to receive at least a portion of said cooled stream under pressure and to expand it to a lower pressure, whereby said stream is further cooled; and
- (c) a distillation column connected to receive said further cooled stream, said distillation column being adapted to separate said further cooled stream into a vapor distillation stream and said relatively less volatile fraction;
- the improvement wherein said apparatus includes
- (1) said first cooling means being adapted to cool said feed gas under pressure sufficiently to partially condense it;
- (2) separating means connected to said first cooling means to receive said partially condensed feed and to separate it into a vapor stream and at least one liquid stream;
- (3) dividing means connected to said separating means to receive said vapor stream and to divide it into first and second streams;
- (4) combining means connected to said dividing means and said separating means to receive said first stream and at least a portion of said at least one liquid stream and form a combined stream;
- (5) second cooling means connected to said combining means to receive said combined stream and to cool it sufficiently to substantially condense it;
- (6) second expansion means connected to said second cooling means to receive said substantially condensed combined stream and to expand it to said lower pressure, said second expansion means being further connected to a contacting and separating means to supply said expanded cooled combined stream to said contacting and separating means at a mid-column feed position, said contacting and separating means being adapted to produce an overhead vapor stream and a bottom liquid stream;
- (7) said first expansion means being connected to said dividing means to receive said second stream and to expand it to said lower pressure, said first expansion means being further connected to said contacting and separating means to supply said expanded second stream to said contacting and separating means at a first lower feed position;
- (8) said distillation column being connected to said contacting and separating means to receive at least a portion of said bottom liquid stream;
- (9) third expansion means connected to said separating means to receive any remaining portion of said at least one liquid stream and to expand it to said lower pressure, said third expansion means being further connected to said distillation column to supply said expanded liquid stream to said distillation column at a mid-column feed position;
- (10) vapor withdrawing means connected to said distillation column to receive said vapor distillation stream and form at least a first distillation stream;
- (11) compressing means connected to said vapor withdrawing means to receive said first distillation stream and to compress it to higher pressure;
- (12) heat exchange means connected to said compressing means to receive said compressed first distillation stream and to cool it sufficiently to condense at least a part of it, thereby forming a condensed stream;
- (13) fourth expansion means connected to said heat exchange means to receive at least a portion of said condensed stream and to expand it to said lower pressure, said fourth expansion means being further connected to said contacting and separating means to supply said at least a portion of said expanded condensed stream to said contacting and separating means at a top feed position;
- (14) said vapor withdrawing means being further connected to said contacting and separating means to direct any remaining portion of said vapor distillation stream to said contacting and separating means at a second lower feed position;
- (15) said contacting and separating means being further connected to said heat exchange means to direct at least a portion of said overhead vapor stream separated therein into heat exchange relation with said compressed first distillation stream and to heat said overhead vapor stream, thereby to supply at least a portion of the cooling of step (12), and thereafter discharging at least a portion of said heated overhead vapor stream as said volatile residue gas fraction; and
- (16) control means adapted to regulate the quantities and temperatures of said feed streams to said contacting and separating means to maintain the overhead temperature of said contacting and separating means at a temperature whereby the major portions of the components in said relatively less volatile fraction are recovered.
37. In an apparatus for the separation of a gas stream containing methane, C2 components, C3 components, and heavier hydrocarbon components into a volatile residue gas fraction and a relatively less volatile fraction containing a major portion of said C2 components, C3 components, and heavier hydrocarbon components or said C3 components and heavier hydrocarbon components, in said apparatus there being
- (a) a first cooling means to cool said gas under pressure connected to provide a cooled stream under pressure;
- (b) a first expansion means connected to receive at least a portion of said cooled stream under pressure and to expand it to a lower pressure, whereby said stream is further cooled; and
- (c) a distillation column connected to receive said further cooled stream, said distillation column being adapted to separate said further cooled stream into a vapor distillation stream and said relatively less volatile fraction;
- the improvement wherein said apparatus includes
- (1) dividing means prior to said first cooling means to divide said feed gas into first and second streams;
- (2) second cooling means connected to said dividing means to receive said first stream and to cool it sufficiently to substantially condense it;
- (3) second expansion means connected to said second cooling means to receive said substantially condensed first stream and to expand it to said lower pressure, said second expansion means being further connected to a contacting and separating means to supply said expanded cooled first stream to said contacting and separating means at a mid-column feed position, said contacting and separating means being adapted to produce an overhead vapor stream and a bottom liquid stream;
- (4) said first cooling means being connected to said dividing means to receive said second stream, said first cooling means being adapted to cool said second stream under pressure sufficiently to partially condense it;
- (5) separating means connected to said first cooling means to receive said partially condensed second stream and to separate it into a vapor stream and at least one liquid stream;
- (6) said first expansion means being connected to said separating means to receive said vapor stream and to expand it to said lower pressure, said first expansion means being further connected to said contacting and separating means to supply said expanded vapor stream to said contacting and separating means at a first lower feed position;
- (7) said distillation column being connected to said contacting and separating means to receive at least a portion of said bottom liquid stream;
- (8) third expansion means connected to said separating means to receive at least a portion of said at least one liquid stream and to expand it to said lower pressure, said third expansion means being further connected to said distillation column to supply said expanded liquid stream to said distillation column at a mid-column feed position;
- (9) vapor withdrawing means connected to said distillation column to receive said vapor distillation stream and form at least a first distillation stream;
- (10) compressing means connected to said vapor withdrawing means to receive said first distillation stream and to compress it to higher pressure;
- (11) heat exchange means connected to said compressing means to receive said compressed first distillation stream and to cool it sufficiently to condense at least a part of it, thereby forming a condensed stream;
- (12) fourth expansion means connected to said heat exchange means to receive at least a portion of said condensed stream and to expand it to said lower pressure, said fourth expansion means being further connected to said contacting and separating means to supply said at least a portion of said expanded condensed stream to said contacting and separating means at a top feed position;
- (13) said vapor withdrawing means being further connected to said contacting and separating means to direct any remaining portion of said vapor distillation stream to said contacting and separating means at a second lower feed position;
- (14) said contacting and separating means being further connected to said heat exchange means to direct at least a portion of said overhead vapor stream separated therein into heat exchange relation with said compressed first distillation stream and to heat said overhead vapor stream, thereby to supply at least a portion of the cooling of step (11), and thereafter discharging at least a portion of said heated overhead vapor stream as said volatile residue gas fraction; and
- (15) control means adapted to regulate the quantities and temperatures of said feed streams to said contacting and separating means to maintain the overhead temperature of said contacting and separating means at a temperature whereby the major portions of the components in said relatively less volatile fraction are recovered.
38. In an apparatus for the separation of a gas stream containing methane, C2 components, C3 components, and heavier hydrocarbon components into a volatile residue gas fraction and a relatively less volatile fraction containing a major portion of said C2 components, C3 components, and heavier hydrocarbon components or said C3 components and heavier hydrocarbon components, in said apparatus there being
- (a) a first cooling means to cool said gas under pressure connected to provide a cooled stream under pressure;
- (b) a first expansion means connected to receive at least a portion of said cooled stream under pressure and to expand it to a lower pressure, whereby said stream is further cooled; and
- (c) a distillation column connected to receive said further cooled stream, said distillation column being adapted to separate said further cooled stream into a first overhead vapor stream and said relatively less volatile fraction;
- the improvement wherein said apparatus includes
- (1) dividing means connected to said first cooling means to receive said cooled stream and to divide it into first and second streams;
- (2) second cooling means connected to said dividing means to receive said first stream and to cool it sufficiently to substantially condense it;
- (3) second expansion means connected to said second cooling means to receive said substantially condensed first stream and to expand it to said lower pressure, said second expansion means being further connected to a contacting and separating means to supply said expanded cooled first stream to said contacting and separating means at a mid-column feed position, said contacting and separating means being adapted to produce a second overhead vapor stream and a bottom liquid stream;
- (4) said first expansion means being connected to said dividing means to receive said second stream and to expand it to said lower pressure, said first expansion means being further connected to said contacting and separating means to supply said expanded second stream to said contacting and separating means at a first lower feed position;
- (5) vapor withdrawing means connected to said contacting and separating means to receive a vapor distillation stream from a region of said contacting and separating means above said feed position of said expanded second stream;
- (6) compressing means connected to said vapor withdrawing means to receive said vapor distillation stream and to compress it to higher pressure;
- (7) heat exchange means connected to said compressing means to receive said compressed vapor distillation stream and to cool it sufficiently to condense at least a part of it, thereby forming a condensed stream;
- (8) third expansion means connected to said heat exchange means to receive at least a portion of said condensed stream and to expand it to said lower pressure, said third expansion means being further connected to said contacting and separating means to supply said at least a portion of said expanded condensed stream to said contacting and separating means at a top feed position;
- (9) said distillation column being connected to said contacting and separating means to receive at least a portion of said bottom liquid stream;
- (10) said distillation column being further connected to said contacting and separating means to direct said first overhead vapor stream to said contacting and separating means at a second lower feed position;
- (11) said contacting and separating means being further connected to said heat exchange means to direct at least a portion of said second overhead vapor stream separated therein into heat exchange relation with said compressed vapor distillation stream and to heat said second overhead vapor stream, thereby to supply at least a portion of the cooling of step (7), and thereafter discharging at least a portion of said heated second overhead vapor stream as said volatile residue gas fraction; and
- (12) control means adapted to regulate the quantities and temperatures of said feed streams to said contacting and separating means to maintain the overhead temperature of said contacting and separating means at a temperature whereby the major portions of the components in said relatively less volatile fraction are recovered.
39. In an apparatus for the separation of a gas stream containing methane, C2 components, C3 components, and heavier hydrocarbon components into a volatile residue gas fraction and a relatively less volatile fraction containing a major portion of said C2 components, C3 components, and heavier hydrocarbon components or said C3 components and heavier hydrocarbon components, in said apparatus there being
- (a) a first cooling means to cool said gas under pressure connected to provide a cooled stream under pressure;
- (b) a first expansion means connected to receive at least a portion of said cooled stream under pressure and to expand it to a lower pressure, whereby said stream is further cooled; and
- (c) a distillation column connected to receive said further cooled stream, said distillation column being adapted to separate said further cooled stream into a first overhead vapor stream and said relatively less volatile fraction;
- the improvement wherein said apparatus includes
- (1) dividing means prior to said first cooling means to divide said feed gas into first and second streams;
- (2) second cooling means connected to said dividing means to receive said first stream and to cool it sufficiently to substantially condense it;
- (3) second expansion means connected to said second cooling means to receive said substantially condensed first stream and to expand it to said lower pressure, said second expansion means being further connected to a contacting and separating means to supply said expanded cooled first stream to said contacting and separating means at a mid-column feed position, said contacting and separating means being adapted to produce a second overhead vapor stream and a bottom liquid stream;
- (4) said first cooling means being connected to said dividing means to receive said second stream and to cool it;
- (5) said first expansion means being connected to said first cooling means to receive said cooled second stream and to expand it to said lower pressure, said first expansion means being further connected to said contacting and separating means to supply said expanded cooled second stream to said contacting and separating means at a first lower feed position;
- (6) vapor withdrawing means connected to said contacting and separating means to receive a vapor distillation stream from a region of said contacting and separating means above said feed position of said expanded cooled second stream;
- (7) compressing means connected to said vapor withdrawing means to receive said vapor distillation stream and to compress it to higher pressure;
- (8) heat exchange means connected to said compressing means to receive said compressed vapor distillation stream and to cool it sufficiently to condense at least a part of it, thereby forming a condensed stream;
- (9) third expansion means connected to said heat exchange means to receive at least a portion of said condensed stream and to expand it to said lower pressure, said third expansion means being further connected to said contacting and separating means to supply said at least a portion of said expanded condensed stream to said contacting and separating means at a top feed position;
- (10) said distillation column being connected to said contacting and separating means to receive at least a portion of said bottom liquid stream;
- (11) said distillation column being further connected to said contacting and separating means to direct said first overhead vapor stream to said contacting and separating means at a second lower feed position;
- (12) said contacting and separating means being further connected to said heat exchange means to direct at least a portion of said second overhead vapor stream separated therein into heat exchange relation with said compressed vapor distillation stream and to heat said second overhead vapor stream, thereby to supply at least a portion of the cooling of step (8), and thereafter discharging at least a portion of said heated second overhead vapor stream as said volatile residue gas fraction; and
- (13) control means adapted to regulate the quantities and temperatures of said feed streams to said contacting and separating means to maintain the overhead temperature of said contacting and separating means at a temperature whereby the major portions of the components in said relatively less volatile fraction are recovered.
40. In an apparatus for the separation of a gas stream containing methane, C2 components, C3 components, and heavier hydrocarbon components into a volatile residue gas fraction and a relatively less volatile fraction containing a major portion of said C2 components, C3 components, and heavier hydrocarbon components or said C3 components and heavier hydrocarbon components, in said apparatus there being
- (a) a first cooling means to cool said gas under pressure connected to provide a cooled stream under pressure;
- (b) a first expansion means connected to receive at least a portion of said cooled stream under pressure and to expand it to a lower pressure, whereby said stream is further cooled; and
- (c) a distillation column connected to receive said further cooled stream, said distillation column being adapted to separate said further cooled stream into a first overhead vapor stream and said relatively less volatile fraction;
- the improvement wherein said apparatus includes
- (1) said first cooling means being adapted to cool said feed gas under pressure sufficiently to partially condense it;
- (2) separating means connected to said first cooling means to receive said partially condensed feed and to separate it into a vapor stream and at least one liquid stream;
- (3) dividing means connected to said separating means to receive said vapor stream and to divide it into first and second streams;
- (4) second cooling means connected to said dividing means to receive said first stream and to cool it sufficiently to substantially condense it;
- (5) second expansion means connected to said second cooling means to receive said substantially condensed first stream and to expand it to said lower pressure, said second expansion means being further connected to a contacting and separating means to supply said expanded cooled first stream to said contacting and separating means at a mid-column feed position, said contacting and separating means being adapted to produce a second overhead vapor stream and a bottom liquid stream;
- (6) said first expansion means being connected to said dividing means to receive said second stream and to expand it to said lower pressure, said first expansion means being further connected to said contacting and separating means to supply said expanded second stream to said contacting and separating means at a first lower feed position;
- (7) vapor withdrawing means connected to said contacting and separating means to receive a vapor distillation stream from a region of said contacting and separating means above said feed position of said expanded second stream;
- (8) compressing means connected to said vapor withdrawing means to receive said vapor distillation stream and to compress it to higher pressure;
- (9) heat exchange means connected to said compressing means to receive said compressed vapor distillation stream and to cool it sufficiently to condense at least a part of it, thereby forming a condensed stream;
- (10) third expansion means connected to said heat exchange means to receive at least a portion of said condensed stream and to expand it to said lower pressure, said third expansion means being further connected to said contacting and separating means to supply said at least a portion of said expanded condensed stream to said contacting and separating means at a top feed position;
- (11) said distillation column being connected to said contacting and separating means to receive at least a portion of said bottom liquid stream;
- (12) fourth expansion means connected to said separating means to receive at least a portion of said at least one liquid stream and to expand it to said lower pressure, said fourth expansion means being further connected to said distillation column to supply said expanded liquid stream to said distillation column at a mid-column feed position;
- (13) said distillation column being further connected to said contacting and separating means to direct said first overhead vapor stream to said contacting and separating means at a second lower feed position;
- (14) said contacting and separating means being further connected to said heat exchange means to direct at least a portion of said second overhead vapor stream separated therein into heat exchange relation with said compressed vapor distillation stream and to heat said second overhead vapor stream, thereby to supply at least a portion of the cooling of step (9), and thereafter discharging at least a portion of said heated second overhead vapor stream as said volatile residue gas fraction; and
- (15) control means adapted to regulate the quantities and temperatures of said feed streams to said contacting and separating means to maintain the overhead temperature of said contacting and separating means at a temperature whereby the major portions of the components in said relatively less volatile fraction are recovered.
41. In an apparatus for the separation of a gas stream containing methane, C2 components, C3 components, and heavier hydrocarbon components into a volatile residue gas fraction and a relatively less volatile fraction containing a major portion of said C2 components, C3 components, and heavier hydrocarbon components or said C3 components and heavier hydrocarbon components, in said apparatus there being
- (a) a first cooling means to cool said gas under pressure connected to provide a cooled stream under pressure;
- (b) a first expansion means connected to receive at least a portion of said cooled stream under pressure and to expand it to a lower pressure, whereby said stream is further cooled; and
- (c) a distillation column connected to receive said further cooled stream, said distillation column being adapted to separate said further cooled stream into a first overhead vapor stream and said relatively less volatile fraction;
- the improvement wherein said apparatus includes
- (1) said first cooling means being adapted to cool said feed gas under pressure sufficiently to partially condense it;
- (2) separating means connected to said first cooling means to receive said partially condensed feed and to separate it into a vapor stream and at least one liquid stream;
- (3) dividing means connected to said separating means to receive said vapor stream and to divide it into first and second streams;
- (4) combining means connected to said dividing means and said separating means to receive said first stream and at least a portion of said at least one liquid stream and form a combined stream;
- (5) second cooling means connected to said combining means to receive said combined stream and to cool it sufficiently to substantially condense it;
- (6) second expansion means connected to said second cooling means to receive said substantially condensed combined stream and to expand it to said lower pressure, said second expansion means being further connected to a contacting and separating means to supply said expanded cooled combined stream to said contacting and separating means at a mid-column feed position, said contacting and separating means being adapted to produce a second overhead vapor stream and a bottom liquid stream;
- (7) said first expansion means being connected to said dividing means to receive said second stream and to expand it to said lower pressure, said first expansion means being further connected to said contacting and separating means to supply said expanded second stream to said contacting and separating means at a first lower feed position;
- (8) vapor withdrawing means connected to said contacting and separating means to receive a vapor distillation stream from a region of said contacting and separating means above said feed position of said expanded second stream;
- (9) compressing means connected to said vapor withdrawing means to receive said vapor distillation stream and to compress it to higher pressure;
- (10) heat exchange means connected to said compressing means to receive said compressed vapor distillation stream and to cool it sufficiently to condense at least a part of it, thereby forming a condensed stream;
- (11) third expansion means connected to said heat exchange means to receive at least a portion of said condensed stream and to expand it to said lower pressure, said third expansion means being further connected to said contacting and separating means to supply said at least a portion of said expanded condensed stream to said contacting and separating means at a top feed position;
- (12) said distillation column being connected to said contacting and separating means to receive at least a portion of said bottom liquid stream;
- (13) fourth expansion means connected to said separating means to receive any remaining portion of said at least one liquid stream and to expand it to said lower pressure, said fourth expansion means being further connected to said distillation column to supply said expanded liquid stream to said distillation column at a mid-column feed position;
- (14) said distillation column being further connected to said contacting and separating means to direct said first overhead vapor stream to said contacting and separating means at a second lower feed position;
- (15) said contacting and separating means being further connected to said heat exchange means to direct at least a portion of said second overhead vapor stream separated therein into heat exchange relation with said compressed vapor distillation stream and to heat said second overhead vapor stream, thereby to supply at least a portion of the cooling of step (10), and thereafter discharging at least a portion of said heated second overhead vapor stream as said volatile residue gas fraction; and
- (16) control means adapted to regulate the quantities and temperatures of said feed streams to said contacting and separating means to maintain the overhead temperature of said contacting and separating means at a temperature whereby the major portions of the components in said relatively less volatile fraction are recovered.
42. In an apparatus for the separation of a gas stream containing methane, C2 components, C3 components, and heavier hydrocarbon components into a volatile residue gas fraction and a relatively less volatile fraction containing a major portion of said C2 components, C3 components, and heavier hydrocarbon components or said C3 components and heavier hydrocarbon components, in said apparatus there being
- (a) a first cooling means to cool said gas under pressure connected to provide a cooled stream under pressure;
- (b) a first expansion means connected to receive at least a portion of said cooled stream under pressure and to expand it to a lower pressure, whereby said stream is further cooled; and
- (c) a distillation column connected to receive said further cooled stream, said distillation column being adapted to separate said further cooled stream into a first overhead vapor stream and said relatively less volatile fraction;
- the improvement wherein said apparatus includes
- (1) dividing means prior to said first cooling means to divide said feed gas into first and second streams;
- (2) second cooling means connected to said dividing means to receive said first stream and to cool it sufficiently to substantially condense it;
- (3) second expansion means connected to said second cooling means to receive said substantially condensed first stream and to expand it to said lower pressure, said second expansion means being further connected to a contacting and separating means to supply said expanded cooled first stream to said contacting and separating means at a mid-column feed position, said contacting and separating means being adapted to produce a second overhead vapor stream and a bottom liquid stream;
- (4) said first cooling means being connected to said dividing means to receive said second stream, said first cooling means being adapted to cool said second stream under pressure sufficiently to partially condense it;
- (5) separating means connected to said first cooling means to receive said partially condensed second stream and to separate it into a vapor stream and at least one liquid stream;
- (6) said first expansion means being connected to said separating means to receive said vapor stream and to expand it to said lower pressure, said first expansion means being further connected to said contacting and separating means to supply said expanded vapor stream to said contacting and separating means at a first lower feed position;
- (7) vapor withdrawing means connected to said contacting and separating means to receive a vapor distillation stream from a region of said contacting and separating means above said feed position of said expanded vapor stream;
- (8) compressing means connected to said vapor withdrawing means to receive said vapor distillation stream and to compress it to higher pressure;
- (9) heat exchange means connected to said compressing means to receive said compressed vapor distillation stream and to cool it sufficiently to condense at least a part of it, thereby forming a condensed stream;
- (10) third expansion means connected to said heat exchange means to receive at least a portion of said condensed stream and to expand it to said lower pressure, said third expansion means being further connected to said contacting and separating means to supply said at least a portion of said expanded condensed stream to said contacting and separating means at a top feed position;
- (11) said distillation column being connected to said contacting and separating means to receive at least a portion of said bottom liquid stream;
- (12) fourth expansion means connected to said separating means to receive at least a portion of said at least one liquid stream and to expand it to said lower pressure, said fourth expansion means being further connected to said distillation column to supply said expanded liquid stream to said distillation column at a mid-column feed position;
- (13) said distillation column being further connected to said contacting and separating means to direct said first overhead vapor stream to said contacting and separating means at a second lower feed position;
- (14) said contacting and separating means being further connected to said heat exchange means to direct at least a portion of said second overhead vapor stream separated therein into heat exchange relation with said compressed vapor distillation stream and to heat said second overhead vapor stream, thereby to supply at least a portion of the cooling of step (9), and thereafter discharging at least a portion of said heated second overhead vapor stream as said volatile residue gas fraction; and
- (15) control means adapted to regulate the quantities and temperatures of said feed streams to said contacting and separating means to maintain the overhead temperature of said contacting and separating means at a temperature whereby the major portions of the components in said relatively less volatile fraction are recovered.
43. The improvement according to claim 28 wherein said vapor withdrawing means is connected to said distillation column to receive a vapor distillation stream from a region of said distillation column above said expanded second stream.
44. The improvement according to claim 29 wherein said vapor withdrawing means is connected to said distillation column to receive a vapor distillation stream from a region of said distillation column above said expanded cooled second stream.
45. The improvement according to claim 30 or 31 wherein said vapor withdrawing means is connected to said distillation column to receive a vapor distillation stream from a region of said distillation column above said expanded second stream.
46. The improvement according to claim 32 wherein said vapor withdrawing means is connected to said distillation column to receive a vapor distillation stream from a region of said distillation column above said expanded vapor stream.
47. The improvement according to claim 28 wherein
- (1) a second dividing means is connected to said heat exchange means to receive said condensed stream and to divide it into at least a first portion and a second portion, said second dividing means being further connected to said third expansion means to supply said first portion to said third expansion means;
- (2) said third expansion means being adapted to expand said first portion to said lower pressure, and thereafter to supply said expanded first portion to said distillation column at said top feed position; and
- (3) fourth expansion means connected to said second dividing means to receive said second portion and to expand it to said lower pressure, said fourth expansion means being further connected to said distillation column to supply said expanded second portion to said distillation column at a mid-column feed position above that of said expanded second stream.
48. The improvement according to claim 29 wherein
- (1) a second dividing means is connected to said heat exchange means to receive said condensed stream and to divide it into at least a first portion and a second portion, said second dividing means being further connected to said third expansion means to supply said first portion to said third expansion means;
- (2) said third expansion means being adapted to expand said first portion to said lower pressure, and thereafter to supply said expanded first portion to said distillation column at said top feed position; and
- (3) fourth expansion means connected to said second dividing means to receive said second portion and to expand it to said lower pressure, said fourth expansion means being further connected to said distillation column to supply said expanded second portion to said distillation column at a mid-column feed position above that of said expanded cooled second stream.
49. The improvement according to claim 30 or 31 wherein
- (1) a second dividing means is connected to said heat exchange means to receive said condensed stream and to divide it into at least a first portion and a second portion, said second dividing means being further connected to said fourth expansion means to supply said first portion to said fourth expansion means;
- (2) said fourth expansion means being adapted to expand said first portion to said lower pressure, and thereafter to supply said expanded first portion to said distillation column at said top feed position; and
- (3) fifth expansion means connected to said second dividing means to receive said second portion and to expand it to said lower pressure, said fifth expansion means being further connected to said distillation column to supply said expanded second portion to said distillation column at a mid-column feed position above that of said expanded second stream.
50. The improvement according to claim 32 wherein
- (1) a second dividing means is connected to said heat exchange means to receive said condensed stream and to divide it into at least a first portion and a second portion, said second dividing means being further connected to said fourth expansion means to supply said first portion to said fourth expansion means;
- (2) said fourth expansion means being adapted to expand said first portion to said lower pressure, and thereafter to supply said expanded first portion to said distillation column at said top feed position; and
- (3) fifth expansion means connected to said second dividing means to receive said second portion and to expand it to said lower pressure, said fifth expansion means being further connected to said distillation column to supply said expanded second portion to said distillation column at a mid-column feed position above that of said expanded vapor stream.
51. The improvement according to claim 33 wherein
- (1) a second dividing means is connected to said heat exchange means to receive said condensed stream and to divide it into at least a first portion and a second portion, said second dividing means being further connected to said third expansion means to supply said first portion to said third expansion means;
- (2) said third expansion means being adapted to expand said first portion to said lower pressure, and thereafter to supply said expanded first portion to said contacting and separating means at said top feed position; and
- (3) fourth expansion means connected to said second dividing means to receive said second portion and to expand it to said lower pressure, said fourth expansion means being further connected to said contacting and separating means to supply said expanded second portion to said contacting and separating means at a mid-column feed position above that of said expanded second stream.
52. The improvement according to claim 34 wherein
- (1) a second dividing means is connected to said heat exchange means to receive said condensed stream and to divide it into at least a first portion and a second portion, said second dividing means being further connected to said third expansion means to supply said first portion to said third expansion means;
- (2) said third expansion means being adapted to expand said first portion to said lower pressure, and thereafter to supply said expanded first portion to said contacting and separating means at said top feed position; and
- (3) fourth expansion means connected to said second dividing means to receive said second portion and to expand it to said lower pressure, said fourth expansion means being further connected to said contacting and separating means to supply said expanded second portion to said contacting and separating means at a mid-column feed position above that of said expanded cooled second stream.
53. The improvement according to claim 35 or 36 wherein
- (1) a second dividing means is connected to said heat exchange means to receive said condensed stream and to divide it into at least a first portion and a second portion, said second dividing means being further connected to said fourth expansion means to supply said first portion to said fourth expansion means;
- (2) said fourth expansion means being adapted to expand said first portion to said lower pressure, and thereafter to supply said expanded first portion to said contacting and separating means at said top feed position; and
- (3) fifth expansion means connected to said second dividing means to receive said second portion and to expand it to said lower pressure, said fifth expansion means being further connected to said contacting and separating means to supply said expanded second portion to said contacting and separating means at a mid-column feed position above that of said expanded second stream.
54. The improvement according to claim 37 wherein
- (1) a second dividing means is connected to said heat exchange means to receive said condensed stream and to divide it into at least a first portion and a second portion, said second dividing means being further connected to said fourth expansion means to supply said first portion to said fourth expansion means;
- (2) said fourth expansion means being adapted to expand said first portion to said lower pressure, and thereafter to supply said expanded first portion to said contacting and separating means at said top feed position; and
- (3) fifth expansion means connected to said second dividing means to receive said second portion and to expand it to said lower pressure, said fifth expansion means being further connected to said contacting and separating means to supply said expanded second portion to said contacting and separating means at a mid-column feed position above that of said expanded vapor stream.
55. The improvement according to claim 38 or 39 wherein
- (1) a second dividing means is connected to said heat exchange means to receive said condensed stream and to divide it into at least a first portion and a second portion, said second dividing means being further connected to said third expansion means to supply said first portion to said third expansion means;
- (2) said third expansion means being adapted to expand said first portion to said lower pressure, and thereafter to supply said expanded first portion to said contacting and separating means at said top feed position; and
- (3) fourth expansion means connected to said second dividing means to receive said second portion and to expand it to said lower pressure, said fourth expansion means being further connected to said contacting and separating means to supply said expanded second portion to said contacting and separating means at a mid-column feed position above the region wherein said vapor withdrawing means is connected to said contacting and separating means to receive said vapor distillation stream.
56. The improvement according to claim 40, 41, or 42 wherein
- (1) a second dividing means is connected to said heat exchange means to receive said condensed stream and to divide it into at least a first portion and a second portion, said second dividing means being further connected to said third expansion means to supply said first portion to said third expansion means;
- (2) said third expansion means being adapted to expand said first portion to said lower pressure, and thereafter to supply said expanded first portion to said contacting and separating means at said top feed position; and
- (3) fifth expansion means connected to said second dividing means to receive said second portion and to expand it to said lower pressure, said fifth expansion means being further connected to said contacting and separating means to supply said expanded second portion to said contacting and separating means at a mid-column feed position above the region wherein said vapor withdrawing means is connected to said contacting and separating means to receive said vapor distillation stream.
57. The improvement according to claim 43 or 44 wherein
- (1) a second dividing means is connected to said heat exchange means to receive said condensed stream and to divide it into at least a first portion and a second portion, said second dividing means being further connected to said third expansion means to supply said first portion to said third expansion means;
- (2) said third expansion means being adapted to expand said first portion to said lower pressure, and thereafter to supply said expanded first portion to said distillation column at said top feed position; and
- (3) fourth expansion means connected to said second dividing means to receive said second portion and to expand it to said lower pressure, said fourth expansion means being further connected to said distillation column to supply said expanded second portion to said distillation column at a mid-column feed position above the region wherein said vapor withdrawing means is connected to said distillation column to receive said vapor distillation stream.
58. The improvement according to claim 45 wherein
- (1) a second dividing means is connected to said heat exchange means to receive said condensed stream and to divide it into at least a first portion and a second portion, said second dividing means being further connected to said fourth expansion means to supply said first portion to said fourth expansion means;
- (2) said fourth expansion means being adapted to expand said first portion to said lower pressure, and thereafter to supply said expanded first portion to said distillation column at said top feed position; and
- (3) fifth expansion means connected to said second dividing means to receive said second portion and to expand it to said lower pressure, said fifth expansion means being further connected to said distillation column to supply said expanded second portion to said distillation column at a mid-column feed position above the region wherein said vapor withdrawing means is connected to said distillation column to receive said vapor distillation stream.
59. The improvement according to claim 46 wherein
- (1) a second dividing means is connected to said heat exchange means to receive said condensed stream and to divide it into at least a first portion and a second portion, said second dividing means being further connected to said fourth expansion means to supply said first portion to said fourth expansion means;
- (2) said fourth expansion means being adapted to expand said first portion to said lower pressure, and thereafter to supply said expanded first portion to said distillation column at said top feed position; and
- (3) fifth expansion means connected to said second dividing means to receive said second portion and to expand it to said lower pressure, said fifth expansion means being further connected to said distillation column to supply said expanded second portion to said distillation column at a mid-column feed position above the region wherein said vapor withdrawing means is connected to said distillation column to receive said vapor distillation stream.
Type: Application
Filed: Aug 16, 2007
Publication Date: Apr 3, 2008
Applicant: Ortloff Engineers, Ltd. (Midland, TX)
Inventors: Kyle T. Cuellar (Katy, TX), Tony L. Martinez (Odessa, TX), John D. Wilkinson (Midland, TX), Joe T. Lynch (Midland, TX), Hank M. Hudson (Midland, TX)
Application Number: 11/839,693
International Classification: F25J 3/00 (20060101); F25J 1/00 (20060101);