A system and method for argon and nitrogen extraction from a feed stream comprising hydrogen, methane, nitrogen and argon, such as tail gas of an ammonia production plant is provided. The disclosed system and method provides for nitrogen-argon rectification and the methane rejection within a column system comprised of at least one distillation column. Nitrogen and argon are further separated and to produce liquid products. An argon stripping column arrangement is disclosed where residual argon is further removed from the methane-rich fuel gas and recycled back to the feed stream.

A system and method for cryogenic purification of a hydrogen, nitrogen, methane and argon containing feed stream to produce a methane free, hydrogen and nitrogen containing synthesis gas and a methane rich fuel gas, as well as to recover an argon product stream, excess hydrogen, and excess nitrogen is provided. The disclosed system and method are particularly useful as an integrated cryogenic purifier in an ammonia synthesis process in an ammonia plant. The excess nitrogen is a nitrogen stream substantially free of methane and hydrogen that can be used in other parts of the plant, recovered as a gaseous nitrogen product and/or liquefied to produce a liquid nitrogen product.

An apparatus for the separation of air by cryogenic distillation comprises a column system, a heat exchanger, a turbine, means for sending compressed and purified air at a first pressure to be cooled at the first pressure in the heat exchanger, means for sending a first gaseous stream having a nitrogen content at least that of air to be cooled and liquefied or pseudo liquefied in the heat exchanger to form a liquefied stream, means for sending at least part of the liquefied stream to be warmed and vaporized in the heat exchanger to a first intermediate temperature of the heat exchanger to form a vaporized stream, means for removing the vaporized stream from an intermediate section of the heat exchanger, a conduit for sending the vaporized stream to be expanded, in the turbine to form an expanded stream, a conduit for sending at least part of the expanded stream to the column system, a conduit for sending a second gaseous stream having the same nitrogen content as the first stream to be cooled in the heat exchanger, means for removing at least part of the second gaseous stream from an intermediate section of the heat exchanger at a second intermediate temperature and sending the second gaseous stream to the turbine to be expanded with the vaporized stream.

A system and method for argon and nitrogen extraction from a feed stream comprising hydrogen, methane, nitrogen and argon, such as tail gas of an ammonia production plant is provided. The disclosed system and method provides for nitrogen-argon rectification and the methane rejection within a column system comprised of at least one distillation column. Nitrogen and argon are further separated and to produce liquid products. An argon stripping column arrangement is disclosed where residual argon is further removed from the methane-rich fuel gas and recycled back to the feed stream.

An ultra-high-purity oxygen production method and apparatus are provide, in which the method can include a step in which feed oxygen comprising low-boiling-point components as impurities is introduced from a warm end of a main heat exchanger and cooled, then introduced into an oxygen rectification column, and product ultra-high-purity oxygen from which the low-boiling-point components have been removed is drawn as a gas or a liquid from a lower portion of the oxygen rectification column.

A system and method for cryogenic purification of a hydrogen, nitrogen, methane and argon containing feed stream to produce a methane free, hydrogen and nitrogen containing synthesis gas and a methane rich fuel gas, as well as to recover an argon product stream, excess hydrogen, and excess nitrogen is provided. The disclosed system and method are particularly useful as an integrated cryogenic purifier in an ammonia synthesis process in an ammonia plant. The excess nitrogen is a nitrogen stream substantially free of methane and hydrogen that can be used in other parts of the plant, recovered as a gaseous nitrogen product and/or liquefied to produce a liquid nitrogen product.

A process and air separation plant for producing one or more air products by cryogenic separation of air in an air separation plant wherein a first fraction and a second fraction of feed air quantity are post-compressed in a post-compressor from a first pressure level to a second pressure level at least 3 bar above the first pressure level, and are extracted from a post-compressor jointly at the second pressure level, impure nitrogen, the nitrogen content of which lies below an overhead product of a high-pressure column, is extracted from the high-pressure column at the first pressure level and is expanded using a second turboexpander which is mechanically coupled to a first booster, and a fluid enriched with argon is extracted from a low-pressure column, is depleted of argon and is recycled into the low-pressure column.

This invention is about a natural gas isobaric liquefaction apparatus, which is based on the Rankine cycle system of similar thermal energy power circulation apparatus at cryogenic side, a cryogenic liquid pump is used to input power and the refrigerant makes up cold to the natural gas liquefying apparatus, so as to realize the isobaric liquefaction of natural gas. The natural gas liquefying apparatus of this invention can save energy by over 30% as compared with the traditional advanced apparatus with the identical refrigerating capacity, therefore it constitutes a breakthrough to the traditional natural gas liquefaction technology, with substantial economic, social and environmental protection benefits.

A method for cooling a hydrocarbon production stream such as natural gas uses cryogenic nitrogen as a cooling medium (refrigerant) wherein only a portion of a nitrogen refrigerant stream is recovered, with a vapor portion of the nitrogen refrigeration stream being vented from the system. Unlike a conventional sacrificial nitrogen refrigeration process which vents all the nitrogen refrigerant after cooling a production stream, the method comprise means for recovering some of the nitrogen refrigerant thereby improving the operating efficiency of the process compared to conventional sacrificial nitrogen refrigeration processes. Also unlike conventional closed loop nitrogen refrigeration processes which recover all of the nitrogen refrigerant after cooling a production stream, the method can recover nitrogen refrigerant without the complex and costly equipment used in closed loop systems to compress nitrogen vapor.

The invention relates to a facility for producing liquid helium from a source gas mixture substantially comprising nitrogen and helium. The facility includes a cryogenic purifier including a system for separating the nitrogen from the source gas mixture with a view to producing helium at a temperature lower than the temperature of the source gas. The facility also includes a helium liquefier that subjects the helium to a work cycle including, in series: compressing the helium, cooling and decompressing the compressed helium, and reheating the cooled, decompressed helium. The facility includes a helium transfer pipe connecting an outlet of the purifier to an inlet of the liquefier in order to transfer helium produced by the purifier into the work cycle of the liquefier. The facility is characterized in that the cryogenic purifier includes a decompression system that includes an inlet to be connected to a source of pressurized nitrogen gas. Said system for decompressing the nitrogen gas exchanges heat with the separation system in order to transfer cold from the decompressed nitrogen gas to said separation system.