A dual-mode LNG liquefier arrangement that is configurable to operate in a first mode broadly characterized as a low pressure, liquid nitrogen add LNG liquefier without turbo-expansion or a second mode broadly characterized as a low pressure, liquid nitrogen add LNG liquefier with turbo-expansion.

A process comprises a first set of distillation columns and a second set of distillation columns, a low-pressure column of the first set being connected to a column operating at higher pressure of the second set by means of a gas arriving from the top of the column operating at a higher pressure and/or by means of a fluid arriving from the low-pressure column.

A method for producing liquefied natural gas (LNG). A natural gas stream is transported to a liquefaction vessel. The natural gas stream is liquefied on the liquefaction vessel using at least one heat exchanger that exchanges heat between the natural gas stream and a liquid nitrogen stream to at least partially vaporize the liquefied nitrogen stream, thereby forming a warmed nitrogen gas stream and an at least partially condensed natural gas stream comprising LNG. The liquefaction vessel includes at least one tank that only stores liquid nitrogen and at least one tank that only stores LNG.

A method and apparatus for liquefying a feed gas stream comprising natural gas and carbon dioxide. A method includes compressing an input fluid stream to generate a first intermediary fluid stream; cooling the first intermediary fluid stream with a first heat exchanger to generate a second intermediary fluid stream, wherein a temperature of the second intermediary fluid stream is higher than a carbon dioxide-freezing temperature for the second intermediary fluid stream; expanding the second intermediary fluid stream to generate a third intermediary fluid stream, wherein the third intermediary fluid stream comprises solid carbon dioxide; separating the third intermediary fluid stream into a fourth intermediary fluid stream and an output fluid stream, wherein the output fluid stream comprises a liquefied natural gas (LNG) liquid; and utilizing the fourth intermediary fluid stream as a cooling fluid stream for the first heat exchanger.

A method for separating nitrogen from an LNG stream with a nitrogen concentration of greater than 1 mol %. A pressurized LNG stream is produced at a liquefaction facility by liquefying natural gas, where the pressurized LNG stream has a nitrogen concentration of greater than 1 mol %. At least one liquid nitrogen (LIN) stream is received from storage tanks, the at least one LIN stream being produced at a different geographic location from the LNG facility. The pressurized LNG stream is separated in a separation vessel into a vapor stream and a liquid stream. The vapor stream has a nitrogen concentration greater than the nitrogen concentration of the pressurized LNG stream. The liquid stream has a nitrogen concentration less than the nitrogen concentration of the pressurized LNG stream. At least one of the one or more LIN streams is directed to the separation vessel.

Described herein are systems and processes to produce liquefied natural gas (LNG) using liquefied nitrogen (LIN) as the refrigerant. Greenhouse gas contaminants are removed from the LIN using a greenhouse gas removal unit.

The method and the device arc used for the cryogenic decomposition of air in a distillation column system for separating nitrogen and oxygen, said system having a first high-pressure column (23), a low-pressure column (25, 26), and three condenser-evaporators, namely a high-pressure column head condenser (27), a low-pressure column bottom evaporator (28), and an auxiliary condenser (29; 228).

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 apparatus for producing high-purity nitrogen and low-purity oxygen using three-column rectification are provided, in which: nitrogen and oxygen undergo rectification in different columns, with high-purity nitrogen and low-purity oxygen being separated out of air simultaneously, thereby overcoming the shortcomings of conventional low-purity oxygen production equipment, and also reducing equipment investment, lowering energy consumption, increasing product added value, and realizing a circular economy effect.

The distillation column system has a high-pressure column, a low-pressure column, a main condenser and a low-pressure-column top condenser. Feed air is cooled in a main heat exchanger and introduced into the high-pressure column. An oxygen-enriched liquid stream is withdrawn from the high-pressure column and introduced into the low-pressure column. A gaseous nitrogen stream is withdrawn from the high-pressure column, warmed in the main heat exchanger and withdrawn as gaseous pressurized nitrogen product. The high-pressure column has a barrier-plate section arranged immediately above the point at which the feed air is introduced. The oxygen-enriched liquid stream is withdrawn from the high-pressure column above the barrier-plate section. A purge stream is withdrawn below the barrier-plate section. The gaseous nitrogen stream, before being warmed in the main heat exchanger, is warmed in a counter-current subcooler in indirect heat exchange with the oxygen-enriched liquid stream from the high-pressure column.