Abstract: A process and an apparatus are disclosed for separation of a hydrocarbon gas stream containing methane and heavier hydrocarbons and significant quantities of nitrogen and carbon dioxide. The gas stream is cooled and expanded, then fractionated in a first distillation column into a first overhead vapor and a hydrocarbon liquid stream containing the majority of the carbon dioxide. The hydrocarbon liquid stream is fractionated into a hydrocarbon vapor stream and a less volatile fraction comprised of heavier hydrocarbons. The first overhead vapor is cooled, expanded, and separated into vapor and liquid streams. Both streams are cooled and expanded before feeding a second distillation column that produces a second overhead vapor that is predominantly nitrogen and a bottom liquid that is predominantly methane. The bottom liquid is vaporized and combined with the hydrocarbon vapor stream to form a volatile residue gas fraction containing the majority of the methane.

Abstract: A process and an apparatus are disclosed for separation of a hydrocarbon gas stream containing methane and heavier hydrocarbons and significant quantities of nitrogen and carbon dioxide. The gas stream is cooled and expanded, then fractionated in a first distillation column into a first overhead vapor and a hydrocarbon liquid stream containing the majority of the carbon dioxide. The hydrocarbon liquid stream is fractionated into a hydrocarbon vapor stream and a less volatile fraction comprised of heavier hydrocarbons. The first overhead vapor is cooled, expanded, and separated into vapor and liquid streams. Both streams are cooled and expanded before feeding a second distillation column that produces a second overhead vapor that is predominantly nitrogen and a bottom liquid that is predominantly methane. The bottom liquid is vaporized and combined with the hydrocarbon vapor stream to form a volatile residue gas fraction containing the majority of the methane.

Abstract: A process and an apparatus are disclosed for separation of a hydrocarbon gas stream containing methane and heavier hydrocarbons and significant quantities of nitrogen and carbon dioxide. The gas stream is cooled and expanded, then fractionated in a first distillation column into a first overhead vapor and a hydrocarbon liquid stream containing the majority of the carbon dioxide. The hydrocarbon liquid stream is fractionated into a hydrocarbon vapor stream and a less volatile fraction comprised of heavier hydrocarbons. The first overhead vapor is cooled, expanded, and separated into vapor and liquid streams. Both streams are cooled and expanded before feeding a second distillation column that produces a second overhead vapor that is predominantly nitrogen and a bottom liquid that is predominantly methane. The bottom liquid is vaporized and combined with the hydrocarbon vapor stream to form a volatile residue gas fraction containing the majority of the methane.

Abstract: The separation of methane from an admixture (110) with ethane and higher hydrocarbons, especially natural gas, using a scrub column (114), in which the admixture is separated into a methane-rich overhead (116) that is partially condensed (122) to provide reflux to the column (114) and liquid methane-depleted bottoms liquid (126), is improved by providing additional reflux (136) derived from an ethane enriched stream (130) from fractionation (128) of the bottoms liquid. Preferably, absorber liquid (140) from the fractionation (128) also is introduced into the scrub column. The vapor fraction (120) remaining after partial condensation can be liquefied (122) to provide LNG product (124).

Abstract: A process to convert heat into power is set forth wherein, to make the cycle more suitable to low grade heat, the working fluid remains substantially in the liquid state after being heat exchanged against the heat source and a dense fluid expander is used in place of a conventional vapor expander to subsequently work expand the liquid working fluid.

Abstract: Method for gas liquefaction comprising cooling a feed gas by a first refrigeration system in a first heat exchange zone and withdrawing a substantially liquefied stream therefrom, further cooling the substantially liquefied stream by indirect heat exchange with one or more work-expanded refrigerant streams in a second heat exchange zone, and withdrawing therefrom a further cooled, substantially liquefied stream. At least one of the one or more work-expanded refrigerant streams is provided by compressing one or more refrigerant gases to provide a compressed refrigerant stream, cooling all or a portion of the compressed refrigerant stream in a third heat exchange zone to provide a cooled, compressed refrigerant stream, and work expanding the cooled, compressed refrigerant stream to provide one of the one or more work-expanded refrigerant streams.

Abstract: A process for producing an isotopically enriched compound of a desired isotope includes (a) providing a cryogenic reaction zone containing a catalyst adapted to catalyze an isotope exchange reaction at a cryogenic reaction temperature, (b) feeding to the cryogenic reaction zone an enriched mixture comprising at least a compound containing the desired isotope, wherein the enriched mixture is enriched in the desired isotope above a natural abundance of the desired isotope, (c) reacting the enriched mixture in the cryogenic reaction zone thereby forming a resulting mixture containing the isotopically enriched compound, and (d) separating the resulting mixture into an enriched product which is enriched in the isotopically enriched compound and a depleted product which is depleted in the isotopically enriched compound.