Abstract: The present invention relates to a process for the liquefaction of a nitrogen stream produced by separating air components, by using the combination of cryogenic distillation with improved refrigeration. Very cold liquefied natural gas (LNG) is employed as refrigerant, with the LNG currently being revaporized for transportation.Multi-stage component compression is used, with the component feed to each compression stage being precooled using sequential refrigeration from the LNG. Expander means for the coldest air component product stream provides supplemental refrigeration at the cold end beyond that which is available from the refrigerant LNG.

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: A process is set forth for the separation of air by cryogenic distillation in a single column to produce a nitrogen product and an oxygen-enriched product. In the process, at least a portion of the nitrogen product is compressed and recycled to provide reboil at the bottom of the distillation column and to provide some additional reflux to the upper portion of the column. In addition, part of the compressed nitrogen recycle stream is expanded to provide work.

Abstract: A process is set forth for the separation of air by cryogenic distillation in a single column to produce a nitrogen product and an oxygen-enriched product. In the process, at least a portion of the nitrogen product is compressed and recycled to provide reboil at the bottom of the distillation column and to provide some additional reflux to the upper portion of the column. In addition, part of the compressed feed air stream is expanded to provide work, which is used to drive an auxiliary compressor for feed air substream compression.

Abstract: A process is set forth for the separation of air by cryogenic distillation in a single column to produce a nitrogen product and an oxygen-enriched product. In the process, at least a portion of the nitrogen product is compressed and recycled to provide reboil at the bottom of the distillation column and to provide some additional reflux to the upper portion of the column. In addition, part of the compressed air stream is expanded to provide work, which is used to drive an auxiliary compressor for recycle nitrogen stream compression.

Abstract: A method of oxygen recycle on the bottom section of the low-pressure column of a dual-pressure column, with an increase in the bottom section reboil vapor rate, allows an appreciable increase in the production rate of ultra high purity oxygen and a substantial decrease in power required as compared to conventional processes.

Abstract: A process and apparatus is set forth for the separation of air by cryogenic distillation in a rectification column using two nitrogen recycle streams and a sidestream of the feed air stream to reboil the column. One of the nitrogen recycle streams is expanded to provide refrigeration and to provide power to compress the feed air sidestream.

Abstract: A process is described in which gaseous nitrogen is recovered from air in a cryogenic air separation unit containing a single distillation column wherein the product nitrogen is compressed and a portion of the compressed nitrogen is recycled to the column to provide reboil in the bottom of said column and reflux at the top of said column. A waste crude oxygen stream is expanded to provide refrigeration for the air separation unit.

Abstract: A cryogenic air separation system is described in which pressure-swing adsorption driers are used to remove virtually all of the moisture from the feed air prior to the passage of the feed air stream through reversing heat exchangers which remove the carbon dioxide. The reversing heat exchangers are regenerated by at least one outgoing product nitrogen stream, while the adsorption driers are regenerated by all or a portion of a low pressure stream withdrawn from the low pressure column the composition of which may be rich in either nitrogen or oxygen depending upon whether the volume of product nitrogen or oxygen is to be maximized. A portion of this low pressure stream may be recovered as a dry product stream, while an additional stream of high purity product oxygen may also be recovered.