A system and method for an intermediate pressure vessel to receive a purge in a cryogenic distillation column system. The vessel operates at an intermediate pressure to reduce solidification of the purge. The cryogenic distillation column receives a natural gas having methane and acid gas. The column discharges an overhead stream rich in the methane, and a bottoms stream rich in the acid gas. An overhead system receives the overhead stream, and discharges a vapor methane product, and a cooled liquid for reflux to the cryogenic distillation column.

The power required to recover C.sub.3+ hydrocarbons from crude carbon dioxide comprising C.sub.1+ hydrocarbons and hydrogen sulfide may be reduced by distilling the crude carbon dioxide to produce carbon dioxide-enriched overhead vapor and C.sub.3+ hydrocarbon-enriched bottoms liquid such that the hydrogen sulfide is rejected with the overhead vapor. Power consumption reductions may be achieved by incorporating a heat pump cycle using carbon dioxide vapor as working fluid to provide at least a part of the refrigeration duty and using a side reboiler to reduce the bottom reboiler duty. Where the bottoms liquid is further processed to produce lighter and heavier hydrocarbon fractions, the process enables optimization of upgrading crude oil on the basis of API gravity, Reid Vapor pressure and/or viscosity.

A system for liquefying a gas includes a liquefaction heat exchanger having a feed gas inlet adapted to receive a feed gas and a liquefied gas outlet through which the liquefied gas exits after the gas is liquefied in the liquefying passage of the heat exchanger by heat exchange with a primary refrigeration passage. A mixed refrigerant compressor system is configured to provide refrigerant to the primary refrigeration passage. An expander separator is in communication with the liquefied gas outlet of the liquefaction heat exchanger, and a cold gas line is in fluid communication with the expander separator. A cold recovery heat exchanger receives cold vapor from the cold gas line and liquid refrigerant from the mixed refrigerant compressor system so that the refrigerant is cooled using the cold vapor.

A cryogenic installation unit comprises at least one item of equipment to be thermally insulated, a structure for containing the at least one item of equipment, a main insulation contained in the structure and, associated with this main insulation, a secondary insulation of lower thermal conductivity than the main insulation, said secondary insulation consisting of a vacuum insulation panel.

A cryogenic installation unit comprises at least one item of equipment to be thermally insulated, a structure for containing the at least one item of equipment, a main insulation contained in the structure and, associated with this main insulation, a secondary insulation of lower thermal conductivity than the main insulation, said secondary insulation consisting of a vacuum insulation panel.

The invention relates to a method of separating a phosgene- and hydrogen chloride-comprising stream (5), wherein said method comprises conveying the hydrogen chloride- and phosgene-comprising stream (5) into a distillation column (1), withdrawing at the bottom of the distillation column (1) a phosgene-comprising stream (7) and withdrawing at the top of the column an essentially hydrogen chloride-comprising stream (9). At least a portion of the stream (9) withdrawn at the top is compressed and at least partially condensed and at least a portion of the liquid and compressed essentially hydrogen chloride-comprising stream is decompressed and recycled into the top of distillation column (1) as reflux.

Disclosed herein are systems and processes for removing heavies during the liquefaction of a natural gas. The processes include dissolving the heavies in the natural gas by adding external natural gas liquid (NGL), followed by a staged removal of the natural gas liquid (NGL) and dissolved heavies.

The invention relates to a method and device for generating two purified partial air streams under different pressures. A total air stream (1) is compressed to a first total air pressure. The compressed total air stream (5) is cooled with cooling water under the first total air pressure by way of heat exchange (4, 6). The heat exchange with cooling water for cooling the total air stream (5) is carried out as a direct heat exchange in a first direct contact cooler (6), at least in part. The cooled total air stream (9) is divided into a first partial air stream (10) and a second partial air stream (11). The first partial air stream (10) is purified in a first purification device (18) under the first total air pressure, generating the first purified partial air stream (19). The second partial air stream (11) is re-compressed to a higher pressure (12), which is higher than the first total air pressure. The re-compressed second partial air stream (14) is cooled with cooling water in a second direct contact cooler (15) by way of direct heat exchange (13, 15). The cooled second partial air stream (17) is purified under the higher pressure in a second purification device (30), thus generating the second purified partial air stream (31).

Helium can be recovered from nitrogen-rich natural gas at high pressure with low helium loss by cryogenic distillation of the natural gas after pre-treatment of the gas to remove incompatible impurities and then recovery of natural gas liquid (NGL) from the pre-treated gas by distillation. Overall power consumption may be reduced, particularly if the feed to the helium recovery column system is at least substantially condensed by indirect heat exchange against a first portion of nitrogen-enriched bottoms liquid at first pressure, and a second portion of nitrogen-enriched bottoms liquid at a second pressure that is different from the first pressure.

An air separation unit and associated method for separating air by cryogenic distillation using a distillation column system including a higher pressure column, a lower pressure column, an intermediate pressure kettle column, and an argon column arrangement is provided. The disclosed air separation unit and method is particularly suited for production of an argon product as well as several nitrogen products wherein a portion of the nitrogen overhead intermediate pressure kettle column is taken as an intermediate or elevated pressure nitrogen product. The present air separation unit and associated method employs a once-through kettle column reboiler, a once-through kettle column condenser while the argon condenser condenses an argon-rich vapor stream against a pumped oxygen stream from the bottom of the lower pressure column.