A system and method for argon and nitrogen extraction and liquefaction from a low-pressure tail gas of an ammonia production plant is provided. The preferred tail gas of the ammonia production plant comprises methane, nitrogen, argon, and hydrogen. The disclosed system and method provides for the methane rejection via rectification and hydrogen rejection by way of a side stripper column or phase separator. The resulting nitrogen and argon containing stream is separated and liquefied in a double column distillation system.

One object of the present invention is to provide a compact multistage liquid storage-type condenser-evaporator capable of producing two kinds of gases having different compositions without increasing power, and a nitrogen production device using the multistage liquid storage-type condenser-evaporator without increasing the power for producing nitrogen, and the present invention provides a multistage liquid storage-type condenser-evaporator including a bottom liquid storage section which is configured to store the liquid supplied into the bottom evaporation passage without circulating, and a fluid collection section which is configured to collect the fluid which flows out from the bottom evaporation passage and discharge to the outside without returning into the bottom liquid storage section.

A method for the production of liquefied natural gas (LNG) using a cold fluid provided from a cryogenic unit, such as an air separation unit or nitrogen liquefier, is provided. The method may include the steps of: withdrawing a nitrogen stream from a cryogenic unit, wherein the nitrogen stream is at a temperature between about 155 C. to about 193 C.; and liquefying a natural gas stream in a natural gas liquefaction unit using the nitrogen stream from the cryogenic unit.

A system and method serve generate oxygen by low-temperature air separation in a distillation column system having a high-pressure column and a low-pressure column, a main condenser which is constructed as a condenser-evaporator, and an auxiliary column. A gaseous oxygen-containing fraction is introduced into the auxiliary column. A nitrogen-containing liquid stream from the high-pressure column, the main condenser or the low-pressure column is applied as reflux to the top of the auxiliary column. An argon-rich stream from an intermediate site of the low-pressure column is introduced into an argon removal column that has an argon removal column top condenser. The low-pressure column is arranged beside the high-pressure column, the main condenser is arranged over the high-pressure column, the auxiliary column is arranged over the main condenser, the argon removal column is arranged over the auxiliary column and the argon removal column top condenser is arranged over the argon removal column.

A method and apparatus for producing compressed nitrogen and liquid nitrogen. A separation system has a high-pressure column, a low-pressure column with a top condenser and a main condenser. Air is compressed in an air compressor, purified, cooled in a heat exchanger and introduced into the high-pressure column. A first part of the gaseous top nitrogen from the low-pressure column becomes compressed nitrogen product. A second part of the gaseous top nitrogen is condensed in the condensing space of the top condenser and vapour is drawn off as a residual gas stream. The vapor is expanded in a first expansion machine. A second compressed nitrogen stream from the top of the high-pressure column is expanded in a second expansion machine and then drawn off as compressed nitrogen product. A part of the nitrogen condensed in the top condenser is drawn off as liquid nitrogen product.

The method for the production of nitrogen can include the steps of a) providing a waste nitrogen gas stream at a first pressure called low pressure, wherein the waste nitrogen gas originates from a low pressure column of a cryogenic air separation unit; b)compressing the waste nitrogen gas stream to a second pressure in a waste nitrogen compressor to produce a pressurized nitrogen stream; and c) introducing the pressurized nitrogen stream to a nitrogen generator under conditions effective for producing a purified nitrogen product, wherein the purified nitrogen product has a higher concentration of nitrogen as compared to the pressurized nitrogen stream.

Process and apparatus for producing pressurized gaseous nitrogen by cryogenic separation of air. The distillation column system includes a high pressure column, a medium pressure column, a main condenser and top condenser both being condenser-evaporators. Compressed and purified feed air is cooled in a heat exchanger and introduced to the distillation system. A gaseous nitrogen stream from the high pressure column is condensed in the main condenser. Bottom liquid of the medium pressure column is evaporated and gaseous nitrogen from the medium pressure column is condensed in the top condenser. Liquid nitrogen from the medium pressure column is pressurized and introduced to the high pressure column. A second gaseous nitrogen stream from the high pressure column is recovered as pressurized gaseous nitrogen product. A portion of the compressed and purified feed air is work-expanded and then warmed in the main heat exchanger.

A method and system for cryogenic air separation that employs both a primary refrigeration circuit and an auxiliary refrigeration circuit is provided. The auxiliary refrigeration circuit is configured in a manner that it can be easily tied-in or modified to an existing air separation plant.

A method and a device used to variably obtain a compressed-gas product by means of the low-temperature separation of air in a distillation column system. In a first operating mode, a first amount of first compressed-gas product is obtained, and, in a second operating mode, a second, smaller amount is obtained. In the first operating mode, a first amount of high-pressure column nitrogen is compressed in a nitrogen compressor and in the second operating mode, a second, larger amount is compressed in the nitrogen compressor.

A method and device used to variably obtain a compressed-gas product by means low-temperature separation of air in a distillation column system. In a first operating mode, a first amount of first compressed-gas product is obtained, and, in a second operating mode, a second, smaller amount is obtained. In the first operating mode, a first amount of air is compressed in the main air compressor, and in the second operating mode, a second, larger amount is compressed in the main air compressor.