Abstract: A process is set forth for introducing a multicomponent liquid feed stream at pressure P.sub.2 into a distillation column operating at lower pressure P.sub.1. The process comprises removing a split stream from the feed stream, reducing its pressure and using the resulting stream to subcool the feed stream. After being subcooled, the feed stream is also reduced in pressure and both streams are fed to different stages of the distillation column. An important embodiment of the present invention is within the standard double column air separation cycle where the multicomponent liquid stream is the crude liquid oxygen stream from the bottom of the high pressure column which must be reduced in pressure prior to its introduction into the low pressure column.

Abstract: The present invention is an improvement to a process for the conversion of natural gas to produce higher molecular weight hydrocarbon products, wherein the natural gas is partially oxidized to produce a synthesis gas comprising carbon monoxide and hydrogen, wherein the synthesis gas is catalytically reacted to produce the higher molecular weight hydrocarbon products, wherein the conversion process generates excess steam and wherein oxygen used to partially oxidize the natural gas is produced by an air separation process. The improvement is characterized by operating such air separation process at an elevated pressure so that the feed air to the air separation process is compressed to between 8 and 20 Bar(a); expanding at least a portion of the excess steam generated by the conversion process to generate work and using at least a portion of the generated work to drive the compression requirements of the air separation process.

Abstract: A process is set forth for the cryogenic distillation of an air feed to produce a low to medium purity oxygen product using a single distillation column system. The air feed is partially condensed into a crude liquid oxygen stream and a remaining nitrogen-enriched vapor stream by boiling the liquid phase at the bottom of the distillation column. The pressure of the crude liquid oxygen stream is reduced and the nitrogen-enriched vapor stream is subsequently condensed against it to provide reflux to the top of the distillation column. The low to medium purity oxygen product (oxygen concentration between 65% and 99%) is withdrawn from the bottom of the distillation column as liquid, vapor or a combination of both.

Abstract: A process is set forth for the cryogenic distillation of an air feed to produce an ultra-high purity oxygen product. A first oxygen-containing but heavy contaminants-lean (free) stream is removed from the main distillation column system and subsequently stripped in an auxiliary distillation column. A second oxygen-containing but light contaminants-lean (free) gaseous stream is also removed from the main distillation column system and subsequently fed to the bottom section of the auxiliary distillation column in order to provide heat duty/reboil to the bottom of the auxiliary distillation column. The ultra-high purity oxygen product (ie total contaminant concentration less than 10.0 vppm, preferably less than 1.0 vppm) is withdrawn from an intermediate section of the auxiliary distillation column.

Abstract: The present invention relates to a process producing large quantities of liquid product via the cryogenic distillation of air wherein at least a portion of the refrigeration needs of the process is provided by expansion of the feed air. In particular, the present invention is an improved method to meet the liquid nitrogen requirements of the process and comprises elevating the discharge pressure of the nitrogen recycle compressor.

Abstract: This invention relates to an improvement in a process for the separation of a multi-component stream comprising component A, B and C with A being the most volatile and C the least volatile. A multi-component feed is introduced to a multicolumn distillation system comprising a first or main distillation column and a side column wherein at least a light component A is separated from a heavier component C in the main distillation column, the lighter component A being removed as an overhead fraction and the heavier component C being removed as a bottoms fraction. The improvement for enhanced recovery of component B in the side column comprises withdrawing a liquid fraction from the main distillation column at a point intermediate the overhead and feed and introducing that liquid fraction to an upper portion of the side column. Lighter components are withdrawn as an overhead from the side column and returned to an optimal location in the distillation system, typically the main distillation column.

Abstract: A process and system for controlling a cryogenic air separation unit during rapid changes in production. During operation of an air separation unit, demands for oxygen will vary and the pressure of the feed air will fluctuate. The changes in oxygen demand and feed air pressure translate into a ramping, either up or down, of the distillation system pressure in the air separation unit. Because the product streams have tight purity requirements, the ramping system pressure (which could adversely affect product purity) is compensated for. This compensation is by way of a net transfer of refrigeration, in the form of liquid nitrogen, into and out of the distillation system. This transfer of refrigeration is implemented using a storage vessel of liquid nitrogen connected to the reflux path of the distillation system. Liquid nitrogen via the reflux path is removed and stored or added to the distillation system to decrease or increase the refrigeration, respectively.

Abstract: This invention relates to a cryogenic process for the separation of air utilizing an integrated multi-column distillation system wherein a nitrogen rich, oxygen rich and argon rich product are generated. In the cryogenic distillation separation of air, air is initially compressed, pretreated and cooled for separation into its components. Moderate pressure, e.g., 25-80 psia nitrogen is generated with enhanced nitrogen product purity and greater recovery of both nitrogen and argon by effecting a high boil-up rate in the bottom of the lower pressure column, thereby creating a reduced liquid flow/vapor flow ratio (L/V) and utilizing a higher than customary nitrogen reflux to the top of the lower pressure column, where the concentration of oxygen in nitrogen is less than about 10 ppm by volume or the nitrogen purity is at least about 99.5% by volume.Refrigeration to drive the system is obtained by recovering the energy from the waste nitrogen stream and oxygen vapor from the lower pressure column.

Abstract: The present invention relates to an improvement for the production of argon from cryogenic air separation processes. In particular, the improvement provides a better method of thermally linking the top of the crude argon column with the low pressure column. In the improvement, the argon-rich, overhead vapor from the top of the crude argon column is condensed in a boiler/condenser by indirect heat exchange against liquid descending the low pressure column; a portion of the condensed argon-rich, overhead vapor is returned to the top of the crude argon column to provide reflux. The most suitable location for such boiler/condenser is as an intermediate boiler/condenser in the low pressure column, particularly, the section of the low pressure column bounded by the feed point of the crude liquid oxygen from the bottom of the high pressure column and the vapor feed draw line for the crude argon column wherein an adequate temperature difference exists between the descending liquid and the condensing argon.

Abstract: This invention relates to a cryogenic process for the separation of air utilizing an integrated multi-column distillation system wherein a nitrogen rich, oxygen rich and argon rich product are generated. In the cryogenic distillation separation of air, air is initially compressed, pretreated and cooled for separation into its components. Moderate pressure, e.g., 25-80 psia nitrogen is generated with enhanced nitrogen product purity and greater recovery of both nitrogen and argon by effecting a high boil-up rate in the bottom of the lower pressure column, thereby creating a reduced liquid flow/vapor flow ratio (L/V) and utilizing a higher than customary nitrogen reflux to the top of the lower pressure column, where the concentration of oxygen in nitrogen is less than about 10 ppm by volume or the nitrogen purity is at least about 99.5% by volume. Refrigeration to drive the system is obtained by recovering the energy from the waste nitrogen stream and oxygen vapor from the lower pressure column.

Abstract: The present invention relates to an improvement for the production of ultra-high purity oxygen from cryogenic air separation processes which produce nitrogen and/or commercial purity oxygen products. In particular, the improvement comprises removing or producing an oxygen-containing but heavy contaminant-lean (free, stream from one of the distillation columns of a single or multiple column cryogenic air separation facility and further stripping the removed or produced oxygen-containing stream in a fractionator to produce ultra-high purity oxygen (i.e., contaminant concentration <10 vppm).

Abstract: The present invention is a cryogenic process for the production of nitrogen by distilling air in a double column distillation system comprising a high pressure column and a low pressure column. The critical step of the invention is the condensation of a nitrogen stream in the top most reboiler/condenser located in the stripping section of the low pressure column to provide column reboil and the total condensation of a portion of the compressed feed air in the bottom most reboiler/condenser located in the bottom of the low pressure column.

Abstract: The present invention is a cryogenic process for the production of nitrogen by distilling air in a double column distillation system comprising a high pressure column and a low pressure column. The critical step of the invention is the condensation of two nitrogen streams at different pressures in two reboiler/condensers located in the stripping section of the low pressure column to provide column reboil. The lower pressure of the two nitrogen streams is condensed in the upper of the two reboiler/condensers; the higher pressure nitrogen stream in the lower of the two reboiler/condensers.

Abstract: The present invention is an improvement to a method of producing crude argon directly from the cold box of a cryogenic air separation unit. The improvement is the production of crude argon containing greatly decreased concentrations of oxygen, i.e. <0.5% oxygen without any loss in recovery. The improvement is accomplished by using an effective number of theoretical stages in the side arm column so as to produce the desired argon product purity without sacrificing argon recovery; feeding crude liquid oxygen from the bottom of the high pressure column to the reboiler condenser located in the top of the argon side arm column at a rate in the range from about 1.04 to about 1.

Abstract: The present invention is an improvement to a two distillation column, cryogenic air separation process which produces nitrogen-rich and oxygen-rich products. The improvement to the process is condensing at least a portion of the nitrogen overhead from the high pressure column in a reboiler/condenser against a crude liquid oxygen stream and in an intermediate reboiler/condenser located in the low pressure column against internal low pressure column streams. The condensed nitrogen overhead is fed either to the low pressure or high pressure columns as reflux. The vaporized portion of the crude liquid oxygen stream is work expanded to provide some or all of the refrigeration required for the process.

Abstract: The present invention relates to an improvement to a nitrogen or carbon dioxide rejection process used in an enhanced oil recovery project. In rejection processes for enhanced oil recovery projects at least a portion of a feed stream from the reservoir is precooled in a heat exchanger before distillation to separate the feed stream into a nitrogen or carbon dioxide fraction and a methane fraction. The improvement to this rejection process is the precooling of the feed stream by heat exchange with the nitrogen or carbon dioxide fraction and the methane fractions in a plate-fin heat exchanger with at least three circuits.

Abstract: The present invention involves a process for separating and purifying gas mixtures comprising H.sub.2, CO and C.sub.1 + hydrocarbons. The gas is initially cooled in a high pressure dephlegmator to condense and rectify the C.sub.1 + hydrocarbons leaving a combined H.sub.2 --CO vapor. The condensed C.sub.1 + hydrocarbons are partially vaporized and subsequently recondensed in a second, low pressure dephlegmator with further rectification. This process yields H.sub.2 --CO vapor streams and a C.sub.1 + liquid hydrocarbon product at purities suitable for subsequent commercial operations.

Abstract: A method is disclosed for cooling, condensing and subcooling a substantially single component gas stream by passing the gas stream through a heat exchange relationship with a vaporizing multicomponent stream so that carry-up of the condensed liquid phase is maintained without condensed phase backmixing and pot-boiling of the coolant stream is avoided. The single component gas stream is passed through a cold-end up heat exchanger having a serpentine pathway for the gas stream comprising a series of horizontal passes separated by horizontal dividers and alternatingly connected by turnaround passes at each end. The method is particularly applicable to the condensing of a recycle methane stream in a nitrogen rejection process which uses a methane heat pump cycle to provide refrigeration.

Abstract: A method is disclosed for cooling a multicomponent gas stream containing variable amounts of the components by passing the gas stream through a heat exchange relationship with a fluid coolant stream so that carry-up of the condensed phase is maintained without condensed phase backmixing over the compositional range of the multicomponent gas stream. The gas stream is cooled by passing it through a cold-end up heat exchanger having a serpentine pathway for the multicomponent gas stream comprising a series of horizontal passes separated by horizontal dividers and alternatingly connected by turnaround passes at each end, the cross-sectional area of at least one horizontal pass nearer the cold-end being less than the cross-sectional area of a horizontal pass nearer the warm-end. The method is particularly applicable to cooling a natural gas feed stream having a variable nitrogen content in a nitrogen rejection process.

Abstract: Enhanced recovery of the methane content of a multicomponent stream containing lower boiling gas components is obtained by effecting condensation of at least the major portion of the methane content in a dephlegmator wherein separated lower boiling components are employed as indirect heat exchange refrigerants.