Abstract: The method enables the antihydrate compounds contained in a condensed-hydrocarbon liquid feedstock arriving through pipe 1 to be extracted. The liquid feedstock is brought into contact, in zone ZA, with a non-aqueous ionic liquid having the general formula Q+ A31 , where Q+ designates an ammonium, phosphonium, and/or sulfonium cation, and A31 designates an anion able to form a liquid salt. The antihydrate compounds in the liquid hydrocarbon feedstock evacuated through pipe 2 are eliminated. The ionic liquid charged with antihydrate compounds is evacuated through pipe 3, then introduced into evaporator DE to be heated in order to evaporate the antihydrate compounds. The regenerated ionic liquid is recycled through pipes 8 and 9 to zone ZA. The antihydrates are evacuated through pipe 7a.

Abstract: A plant includes an absorber (105) that receives a feed gas (10) at a pressure of at least 400 psig and comprising at least 5 mol % carbon dioxide, wherein the absorber (105) is operated at an isothermal or decreasing top-to-bottom thermal gradient, and wherein the absorber (105) employs a physical solvent to at least partially remove an acid gas from the feed gas (10). Such configuration advantageously provide cooling (108) by expansion of the rich solvent (21) generated in the absorber (105), wherein both a semi-rich solvent (13) generated and recycled to the absorber (105) and the feed gas (10) are cooled by expansion of the rich solvent (21).

Abstract: A process for separating the components of a multi-component gas stream is disclosed. The multi-component gas stream is contacted with a solvent in an extractor at cryogenic temperatures to produce an overhead stream enriched with unabsorbed component(s) and a rich solvent bottoms stream enriched with absorbed component(s). The rich solvent bottoms stream is then flash evaporated to regenerate the lean solvent and to recover the absorbed component(s) as an overhead stream, which is compressed to produce a product stream. The regenerated solvent is recycled to the extractor.

Abstract: A process for the recovery of ethane and heavier hydrocarbon components from a hydrocarbon feed gas stream. Feed gas stream is cooled into a first and second cooled streams. First and second cooled streams are sent to a cold absorber and separated into a first gas stream and a first liquid stream. First gas stream is expanded and sent to a fractionation tower. At least a part of the first liquid stream is sent to a pre-demethanizer stripper tower. Stripper tower produces a stripper overhead stream and a stripper bottoms stream. Stripper overhead vapor stream is cooled and sent to the fractionation tower as second reflux stream. Stripper bottoms stream is supplied to the fractionation tower. Temperatures and pressures of the streams and columns are maintained to recover a major portion of ethane and heavier hydrocarbon components as a bottoms product stream, and produce a residue gas stream at the fractionation tower overhead.

Abstract: A process for the recovery of high purity hydrogen for recycling to a hydroprocessing or similar unit located in an integrated refinery facility includes sampling and providing analytical information on the make-up of the hydrogen-containing feedstream entering the bottom of a stripping column and the composition of the hydrogen recycle stream at, and/or approaching the top of the stripping column to a computer-directed control system in real time for the purpose of controlling the selection and the volumetric flow rate of one or more “refinery solvents” into the column to maximize the removal of non-hydrogen gases from the feedstream and to thereby maximize the percentage of hydrogen in the recycle gas stream.

Abstract: A process and apparatus for the recovery of ethane and heavier components from a hydrocarbon feed gas stream. Feed gas stream is cooled and separated into a vapor stream and a condensed stream. Vapor stream is divided into a first and a second gas streams. First gas stream is expanded and sent to a fractionation tower. Second gas stream is supplied to an absorber tower. At least a part of the first liquid stream is cooled and sent to the absorber. Absorber column produces a lean vapor stream and a second condensed stream. Lean vapor stream is cooled and sent to the fractionation tower. Second condensed stream is subcooled and supplied to the fractionation tower. Temperatures and pressures of the streams and columns are maintained to recover a major portion of ethane and heavier hydrocarbon components as bottom product, and produce at the fractionation tower overhead, a residue gas stream.

Abstract: A process and apparatus for the recovery of ethane, ethylene, propane, propylene, and heavier hydrocarbons from a liquefied natural gas (LNG) stream is disclosed. The LNG feed stream is directed in heat exchanger relation with a warmer distillation stream rising from the fractionation stages of a distillation column, whereby the LNG feed stream is partially heated and the distillation stream is partially condensed. The partially condensed distillation stream is separated to provide volatile residue gas and a reflux stream, whereupon the reflux stream is supplied to the column at a top column feed position. A portion of the partially heated LNG feed stream is supplied to the column at an upper mid-column feed point, and the remaining portion is heated further to partially or totally vaporize it and thereafter supplied to the column at a lower mid-column feed position.

Abstract: The invention relates to a method for treating a natural gas, saturated or not with water, containing essentially hydrocarbons, a substantial amount of hydrogen sulfide and possibly carbon dioxide. The method of the invention comprises a condensation stage intended to condense a major part of the water, a distillation stage wherein a gaseous effluent depleted in hydrogen sulfide and substantially free of water is recovered, and a contacting stage wherein the gaseous effluent from the previous stage is contacted with a solvent so as to obtain a treated gas substantially free of hydrogen sulfide and possibly of carbon dioxide.

Abstract: A process and apparatus to increase the recovery of ethane, propane, and heavier compounds from a hydrocarbon gas stream is provided. The process can be configured to recover ethane and heavier compounds or propane and heavier compounds, depending upon the market conditions. The process utilizes an additional reflux stream to the absorber column that is lean in ethane and propane compared to the deethanizer overhead. The additional reflux stream is taken as a side stream of the residue gas stream that is cooled, condensed, and then fed at the top of the absorber to enhanced C3+ recovery. The additional lean reflux stream can also be taken as a side stream of the first vapor stream from the cold separator.

Abstract: A gas processing plant has a de-ethanizer and a refluxed absorber, wherein the absorber operates at higher pressure than the de-ethanizer, and wherein at least a portion of the absorber bottoms product is expanded to provide cooling for the absorber reflux stream and/or the distillation column feed stream. Especially contemplated gas processing plants include propane and ethane recovery plants, and where the gas processing plant is an ethane recovery plant, it is contemplated that the ethane product comprises no more than 500 ppm carbon dioxide.

Abstract: Feed gas (1) in an improved NGL processing plant is cooled below ambient temperature and above hydrate point of the feed gas to condense heavy components (6) and a significant portion of water (4) contained in the feed gas. The water (4) is removed in a feed gas separator (101) and the condensed liquids are fed into an integrated refluxed stripper (104) that operates as a drier/demethanizer for the condensed liquids, and the uncondensed portion (5) containing light components is further dried (106) and cooled prior to turboexpansion (23) and demethanization (112). Consequently, processing of heavy components in the cold section is eliminated, and feed gas with a wide range of compositions can be efficiently processed for high NGL recovery at substantially the same operating conditions and optimum expander efficiency.

Abstract: A two-column NGL recovery plant includes an absorber (110) and a distillation column (140) in which the absorber (110) receives two cooled reflux streams, wherein one reflux stream (107) comprises a vapor portion of the NGL and wherein the other reflux stream (146) comprises a lean reflux provided by the overhead (144) of the distillation column (140). Contemplat configurations are especially advantageous in a upgrade of an existing NGL plant and typically exhibit C3 recovery of at least 99% and C2 recovery of at least 90%.

Abstract: A method for thawing and removing frozen material from a cryogenic separation unit such as that found in an olefin production plant comprising employing a flushing agent to thaw and remove the frozen material, purging the flushing agent with a gas, and removing residual flushing agent with a solvent that is miscible with the flushing agent and has a freezing temperature substantially lower than the flushing agent.

Abstract: A process for recovering hydrogen from a stream comprised of hydrogen, non-condensable gases, and propane and lighter hydrocarbons, wherein the process comprises the steps of stripping hydrogen and non condensable gases out of the feed light ends stream with methane vapor, washing the stripped hydrogen stream with liquid methane to absorb the non condensable gases, and washing the hydrogen stream with a hydrocarbon lean oil such as liquid ethane to absorb methane, to produce the product hydrogen stream.

Abstract: The natural gas is successively contacted in column CA with a relatively methanol-rich solvent flowing in through line 4, then with a relatively poor solvent flowing in through line 9. The acid gas-containing solvent recovered through line 3 at the bottom of column CA is expanded through valves V1 and V2 to release acid gases through line 6. A fraction of the expanded solvent is distilled in column CR. The regenerated solvent obtained at the bottom of column CR is sent to the top of column CA through line 9. A second fraction of the expanded solvent is mixed with a solvent drawn off from column CR at an intermediate point between the bottom and the top of this column. This mixture of solvents is sent through line 4 into column CA.

Abstract: A process for liquefying natural gas in conjunction with producing a liquid stream containing predominantly hydrocarbons heavier than methane is disclosed. In the process, the natural gas stream to be liquefied is partially cooled, expanded to an intermediate pressure, and supplied to a distillation column. The bottom product from this distillation column preferentially contains the majority of any hydrocarbons heavier than methane that would otherwise reduce the purity of the liquefied natural gas. The residual gas stream from the distillation column is compressed to a higher intermediate pressure, cooled under pressure to condense it, and then expanded to low pressure to form the liquefied natural gas stream.

Abstract: A process for the recovery of ethane, ethylene, propane, propylene and heavier hydrocarbon components from a hydrocarbon gas stream is disclosed. In recent years, the preferred method of separating a hydrocarbon gas stream generally includes supplying at least portions of the gas stream to a fractionation tower having at least one reboiler, and often one or more side reboilers, to supply heat to the column by withdrawing and heating some of the tower liquids to produce stripping vapors that separate the more volatile components from the desired components. The reboiler and side reboilers (if any) are typically integrated into the feed stream cooling scheme to provide at least a portion of the refrigeration needed to condense the desired components for subsequent fractionation in the distillation column.

Abstract: A gas processing plant has a de-ethanizer (106) and a refluxed absorber (103), wherein the absorber (103) operates at higher pressure than the de-ethanizer (106), and wherein at least a portion of the absorber bottoms product (7) is expanded to provide cooling for the absorber reflux stream and/or the distillation column feed stream. Especially contemplated gas processing plants include propane and ethane recovery plants, and where the gas processing plant is an ethane recovery plant, it is contemplated that the ethane product comprises no more than 500 ppm carbon dioxide.

Abstract: A gas processing plant has a de-ethanizer and a refluxed absorber, wherein the absorber operates at higher pressure than the de-ethanizer, and wherein at least a portion of the absorber bottoms product is expanded to provide cooling for the absorber reflux stream and/or the distillation column feed stream. Especially contemplated gas processing plants include propane and ethane recovery plants, and where the gas processing plant is an ethane recovery plant, it is contemplated that the ethane product comprises no more than 500 ppm carbon dioxide.

Abstract: Feed gas (1) in an improved NGL processing plant is cooled below ambient temperature and above hydrate point of the feed gas to condense heavy components (6) and a significant portion of water (4) contained in the feed gas. The water (4) is removed in a feed gas separator (101) and the condensed liquids are fed into an integrated refluxed stripper (104) that operates as a drier/demethanizer for the condensed liquids, and the uncondensed portion (5) containing light components is further dried (106) and cooled prior to turboexpansion (23) and demethanization (112). Consequently, processing of heavy components in the cold section is eliminated, and feed gas with a wide range of compositions can be efficiently processed for high NGL recovery at substantially the same operating conditions and optimum expander efficiency.

Abstract: Process for pretreating a natural gas under pressure containing hydrocarbons, acid compounds such as hydrogen sulfide and carbon dioxide, and water. The natural gas is cooled to condense part of the water. The partially dehydrated natural gas is then contacted with a liquid stream consisting of a majority of hydrogen in two successive contact zones so as to obtain a natural gas containing substantially no water any more. Finally, this dehydrated natural gas is cooled to condense and separate the acid compounds, this cooling stage being carried out by means of a heat exchanger, an expander or a venturi neck.

Abstract: A cryogenic process and apparatus for separating multi-component gaseous hydrocarbon streams to recover both gaseous and liquid compounds. More particularly, the cryogenic processes and apparatus of this invention utilize a high pressure absorber to improve the energy efficiency of processing natural gas for pipeline gas sales and recovering natural gas liquids (NGL) gas from gaseous hydrocarbon streams.

Abstract: A method for thawing and removing frozen material from a cryogenic separation unit such as that found in an olefin production plant comprising employing a flushing agent to thaw and remove the frozen material, purging the flushing agent with a gas, and removing residual flushing agent with a solvent that is miscible with the flushing agent and has a freezing temperature substantially lower than the flushing agent.

Abstract: In an vapor-liquid contactor 4a for flowing down a liquid along the surface of a packing and contacting said liquid with the vapor while ascending the vapor, the improvement being characterized in that said packing is a non-promoting-fluid-dispersion type structured packing A1, A2 in which various types of thin sheets or tubes for determining the flow direction of the above liquid or vapor is laminated and arranged in the perpendicular direction, and said contactor includes at least one fluid distribution unit E1, E2 formed of a rough distribution part C1, C2 to distribute the liquid roughly and a minute distribution part B1, B2 to distribute the liquid minutely and equally.

Abstract: A process for liquefying natural gas in conjunction with processing natural gas to recover natural gas liquids (NGL) is disclosed. In the process, the natural gas stream to be liquefied is taken from one of the streams in the NGL recovery plant and cooled under pressure to condense it. A distillation stream is withdrawn from the NGL recovery plant to provide some of the cooling required to condense the natural gas stream. The condensed natural gas stream is expanded to an intermediate pressure and supplied to a mid-column feed point on a distillation column. The bottom product from this distillation column preferentially contains the majority of any hydrocarbons heavier than methane that would otherwise reduce the purity of the liquefied natural gas, and is routed to the NGL recovery plant so that these heavier hydrocarbons can be recovered in the NGL product.

Abstract: An exhaust gas recovery method and apparatus including: a first process in which volatile organic compound gas in exhaust gas from a exhaust gas discharging source is absorbed into water by a scrubber; a second process in which water including the volatile organic compound, which is obtained in the first process, is frozen and the volatile organic compound herein concentrated such that the water including the volatile organic compound is separated into water including a high concentration of the volatile organic compound, level of concentration being higher than that of the water including the volatile organic compound which is obtained in the first process, and ice; a third process in which cold of the ice obtained in the second process is used; and a fourth process in which the water including a high concentration of the volatile organic compound, which is obtained in the second process, is reused, is provided.

Abstract: Processes and apparatuses are disclosed for the production of a synthetic air product with a variable oxygen content and a varying level of impurities.

Abstract: The process recovers NF3 from a multicomponent fluid containing NF3, one or more components less volatile than NF3, and one or more components more volatile than NF3. The process uses a first distillation column and a second distillation column, each distillation column having a top and a bottom. The process includes the following steps: feeding the multicomponent fluid to the first distillation column at a first feed location below the top of the first distillation column; feeding a cryogenic liquid to the first or second distillation column adjacent the top of the first or second distillation column; withdrawing a mixture containing NF3 from the first distillation column; feeding the mixture to the second distillation column at a second feed location; separating NF3 from the mixture in the second distillation column; and removing a stream of NF3 from the second distillation column.

Abstract: A process for the recovery of ethane, ethylene, propane, propylene and heavier hydrocarbon components from a hydrocarbon gas stream is disclosed. In recent years, the preferred method of separating a hydrocarbon gas stream generally includes supplying at least portions of the gas stream to a fractionation tower having at least one reboiler, and often one or more side reboilers, to supply heat to the column by withdrawing and heating some of the tower liquids to produce stripping vapors that separate the more volatile components from the desired components. The reboiler and side reboilers (if any) are typically integrated into the feed stream cooling scheme to provide at least a portion of the refrigeration needed to condense the desired components for subsequent fractionation in the distillation column.

Abstract: Carbon monoxide is separated from a gaseous mixture containing hydrogen and methane and contaminated with nitrogen by scrubbing carbon monoxide from a vapor portion of the feed by a liquid methane wash; stripping dissolved hydrogen from the resultant CO-loaded liquid methane stream; fractionating the resultant hydrogen-stripped CO-loaded liquid methane stream to separate nitrogen therefrom; and fractionating the resultant nitrogen-freed bottoms liquid into CO product overheads vapor and methane bottoms liquid. If the gaseous mixture also contains argon, argon content can be removed with the methane content to obviate a separate argon-separation stage as required by prior art processes.

Abstract: Carbon monoxide is separated from a gaseous mixture containing hydrogen and contaminated with nitrogen by separating hydrogen and carbon monoxide contents to provide a carbon monoxide-enriched nitrogen-containing stream and separating carbon monoxide and nitrogen contents of said stream in a nitrogen-separation column to provide a nitrogen-enriched overheads vapor and a nitrogen-freed bottoms liquid. The overheads vapor is washed with liquid nitrogen to remove carbon monoxide therefrom and the resultant carbon monoxide-enriched liquid nitrogen is returned to said column as additional reflux. The liquid nitrogen wash simultaneously reduces the loss of carbon monoxide with the nitrogen-enriched vapor and provides refrigeration to the process. When the gaseous feed is a synthesis gas also containing methane, the methane and carbon monoxide contents can be separated before or after separation of the nitrogen and carbon monoxide contents.

Abstract: Described is a process for degasolining by refrigeration of a gas containing condensable hydrocarbons, which is effected in the presence of methanol to avoid the formation of hydrates, said process making it possible to at least partially recover the methanol entrained in the gas, by washing same by means of a liquid hydrocarbon fraction. The process described thus makes it possible to avoid having to compensate for the loss of methanol by a continuous make-up, as is the case with conventional processes. It accordingly enjoys enhanced levels of performance and economy.

Abstract: A process for treating a gas containing methane, at least one higher hydrocarbon and water to eliminate the water and/or extract the higher hydrocarbon(s) comprises dividing the gas to be treated into at least two fractions each of which undergo at least one cooling step, and bringing an aqueous phase fraction obtained after cooling into contact with the gas to be treated. The treatment process uses units with reduced floor space and weight.

Abstract: A process for treating a gas containing methane, at least one higher hydrocarbon and water to eliminate the water and extract the higher hydrocarbon(s) comprises:a) separating the gas to be treated into two streams (1) and (2);b) bringing at least stream (2) into contact with a recycled liquid phase comprising water and a solvent, to obtain an aqueous liquid phase which is depleted in solvent and a gas phase which is charged with solvent;c) separating the aqueous phase which is depleted in solvent and the gas phase which is charged with solvent;d) bringing said aqueous phase which is depleted in solvent into contact with one of the solvent-free gas streams defined at (a), the solvent being extracted from the depleted aqueous phase by the gas, and recovering a gas phase which is rich in solvent and a regenerated aqueous liquid phase;e) mixing the gas phase with either the gas phase from step (b) or the stream (2) upstream of contact step (b);f) cooling the gas phase from the mixing step so as to partially cond

Abstract: The present invention provides an improved method for recovering high purity olefins from cracked gas effluents or other parafin/olefin gaseous mixtures by use of a chemical absorption process.

Abstract: A process for concentrating and recovering methane and carbon dioxide from landfill gas includes absorption of commonly occurring pollutants using a reduced amount of carbon dioxide absorbent which itself may be an in situ derived and recoverable constituent. Separated methane may be concentrated into a high heating value fuel, and a highly pure food-grade carbon dioxide product may also be recovered. Process streams may be used to provide fuel for compression and refrigeration and/or to regenerate carbon dioxide absorbent.

Abstract: A process for the dehydration, deacidification and stripping of a gas, characterized in that:(a) at least one fraction of the gas is contacted with an aqueous phase containing methanol, the resultant gas being thus charged with methanol being withdrawn from stage (a);(b) the gas withdrawn from stage (a) is contacted with a mixture of solvents comprising methanol, water, and a solvent heavier than methanol, the gas leaving stage (b) being thus at least in part freed of the acid gases which it contained initially;(c) the mixture of solvent obtained from stage (b) is at least in part generated by special reduction and/or heating while liberating at least part of the acid gases, the mixture of solvent being at least partially regenerated, or being at the outlet of stage (c) recycled through stage (b); and(d) the gas obtained from (stage b) is refrigerated while producing at least an aqueous phase containing methanol which is at least in part recycled through stage (a).

Abstract: A process for the recovery of propane, propylene and heavier hydrocarbon components from a hydrocarbon gas stream is disclosed. The stream is cooled and/or expanded to partially condense it, then separated to provide a first vapor stream. The first vapor stream is directed into a contacting device whereby a third vapor stream and a C.sub.3 -containing liquid stream are formed. The C.sub.3 -containing liquid stream is directed to a distillation column wherein a second vapor stream is separated to recover a product containing the major portion of the C.sub.3 components and heavier hydrocarbon components. The second vapor stream is directed into heat exchange relation with the third vapor stream to cool the second vapor stream and condense at least a part of it, forming a condensed stream.

Abstract: A cryogenic system for the recovery of fluorine compounds from a carrier gas stream such as an effluent stream from a semiconductor facility comprising three cryogenic rectification columns and a mass transfer contacting device.

Abstract: A process and system for providing cooling service (refrigerant) for a gas separation process wherein the refrigerant is obtained from the system process fluid and after serving as refrigerant is returned to the process side for separation into product.

Abstract: A process and associated apparatus for removing aromatics and/or higher molecular weight hydrocarbons from a methane-based gas stream comprising the steps of (a) condensing a minor portion of the methane-based gas stream thereby producing a two-phase stream, (b) feeding said two phase stream to the upper section of a column, (c) removing from the upper section of the column an aromatic- and/or heavies-depleted gas stream, (d) removing from the lower section of the column an aromatic- and/or heavies-rich liquid stream, (e) contacting via indirect heat exchange the aromatic- and/or heavies-rich liquid stream with a methane-rich stripping gas thereby producing a warmed liquid stream and a cooled stripping gas stream, (f) feeding said cooled stripping gas stream to the lower section of the column; and (g) contacting said two-phase stream and the cooled stripping gas stream in the column thereby producing the aromatic- and/or heavies-depleted gas stream and the aromatic- and/or heavies-rich liquid stream.

Abstract: In a cryogenic condensation scheme used for benzene removal in a process for liquefying natural gas, two series connected separation columns are provided with a feedstream precooled in a heat exchanger to a temperature that will at least condense the benzene component. In the first column, benzene is absorbed and vapor/liquid is separated with the liquid passed to the second column. The second column provides an overhead vapor stream conserved for processing to LNG, and a bottoms stream comprising NGL. The cooling for condensation of gaseous feed in the heat exchanger is controlled by automatically manipulating bypass flow around the heat exchanger responsive to measured vapor flow from the second separation column. Accordingly, the amount of liquid condensed is responsive to the flow rate of vapor withdrawn overhead from the second separation column.

Abstract: Increased recovery of propane, butane and other heavier components found in a natural gas stream is achieved by installing an absorber upstream from an expander and a separator. The separator is downstream from the expander and returns the liquid stream generated by the separator back to the absorber. Additionally, the recovery of propane, butane and other heavier components is enhanced by combining the upper gas stream from a distillation column with the upper gas stream from the absorber prior to injecting this combination into the separator. The upper gas stream removed from the separator is then subsequently processed for the recovery of a predominately methane and ethane gas stream while the bottom liquid stream from the absorber is subsequently distilled for the generation of a stream consisting predominately of propane, butane and other heavy hydrocarbon components. Alternate embodiments include an additional reflux separator in the system, or substitution of an additional absorber for the separator.

Abstract: A cryogenic system for the recovery of fluorine compounds from a carrier gas stream such as an effluent stream from a semiconductor facility comprising combining the carrier gas feed stream with additive liquid to keep fluorine compounds from solidifying and to reduce the vapor pressure of the fluorine compounds, followed by separation and recovery using a cryogenic rectification column system.

Abstract: In the recovery of a pure CO fraction from a charge containing hydrogen, carbon monoxide and methane from which water and carbon dioxide have optionally been removed, the charge is cooled and partially condensed; and the carbon monoxide is scrubbed out with supercooled liquid methane. The resultant hydrogen is stripped out, and the recovered CO/CH.sub.4 -rich fraction is separated by rectification to obtain a pure CO fraction and a CH.sub.4 -rich fraction. The supercooled liquid methane used as the scrubbing agent contains at least 2 to 15 mol % carbon monoxide, preferably 7 to 10 mol % carbon monoxide. Also, the hydrogen stripper and methane scrubbing column can be combined in a single column.

Abstract: A retrofitted unit to an existing simple refrigerated natural gas plant that substantially increases the amounts of propane, butanes and natural gasoline, or ethane, propane, butanes and natural gasoline recovered from the natural gas in the existing gas treatment plant, wherein in one embodiment the existing natural gas treatment plant includes a refrigerated feed cooler, a separator and a stabilizer and the retrofitted unit comprises an NGL absorber, a refrigerated lean solvent cooler and a lean solvent regenerator; and wherein in a second embodiment the existing simple refrigerated gas treatment plant additionally includes an NGL fractionation train that separates the recovered NGL into saleable fractions and wherein the NGL fractionation train includes a debutanizer that produces all or part of the lean solvent utilized in the retrofitted unit which comprises an NGL absorber and a refrigerated solvent cooler.

Abstract: An absorption process for recovering hydrogen, ethylene, methane and heavy hydrocarbons from refinery and petrochemical off-gas streams wherein the absorption solvent is comprised of heavy hydrocarbons derived from the off-gas feed stream; no external solvent is used. The process comprises the steps of absorbing ethylene out of the feed off-gas in an absorber stripper using the absorption solvent, and fractionating the rich absorption solvent in a distillation column to produce an ethylene product stream as the overhead stream and the heavy hydrocarbon absorption solvent as the bottoms stream.

Abstract: A vent gas stream containing volatile organic compounds is passed continuously through a condenser in counter-current flow with respect to cold clean vent gas combined with a cryogenic refrigerant. The volatile organic compounds are condensed at various temperatures inside the condenser, and are separately recovered at very low levels of refrigerant utilization.