A process for providing an oxygen product using an air separation plant having a distillation column system, in which a cryogenic liquid is withdrawn from the distillation column system, wherein a first portion of the cryogenic liquid is subjected to a pressure-increasing evaporation by evaporating a second portion of the cryogenic liquid, and the oxygen product is provided using at least part of the first portion of the cryogenic liquid. At least part of the evaporated second portion of the cryogenic liquid, after the increase in pressure, is made available for further utilization, for the provision of the oxygen product. The present invention also relates to a corresponding air separation plant.

A system and method for co-producing ultra-high purity oxygen and ultra-high purity hydrogen from a water electrolysis unit is provided. The presently disclosed system and method includes upgrading the crude oxygen stream coming from the water electrolysis unit by means of a small, stand-alone cryogenic distillation system wherein the refrigeration for such cryogenic distillation system is supplied by a nitrogen recycle refrigeration loop.

A device and a method for recovering by-product oxygen from water-electrolysis hydrogen production using a low-temperature method are provided, solving the waste problem of by-product oxygen in the green water-electrolysis hydrogen production system. The device according to the present disclosure comprises an oxygen clarifying system, a pressurizing and heat exchanging system, and a circulating gas compression and expansion refrigeration system. The recovering method according to the present disclosure comprises the following steps: first clarifying and purifying the by-product oxygen from water-electrolysis hydrogen production is to remove hydrogen, carbon monoxide, carbon dioxide, water and other impurities in the oxygen; and then, liquefying, pressurizing and heat exchanging the pure oxygen to obtain the product oxygen and liquid oxygen with required pressure. In the whole process, the cooling capacity is provided by the circulating gas expansion refrigeration system.

A nitrogen production system that can produce high purity nitrogen containing a desired concentration of oxygen and ultrahigh purity nitrogen containing a desired concentration of argon in a single rectifying column while restraining increase in electric power consumption and a production process thereof are provided. The method can include the steps of rectifying a cooled and compressed air stream in the rectifying column; withdrawing the ultrahigh purity nitrogen stream from a top portion of the nitrogen rectifying column, warming the ultrahigh purity nitrogen stream in a heat exchanger, and then recovering the ultrahigh purity nitrogen stream from the heat exchanger; and withdrawing a high purity nitrogen stream from a rectification section of the nitrogen rectifying column, warming the high purity nitrogen stream in the heat exchanger, and then recovering the high purity nitrogen stream from the heat exchanger.

In a method for separating air by cryogenic distillation, cooled air purified to remove water is sent to a first column operating at a first pressure, where it is separated into a nitrogen-enriched gas as an oxygen-enriched liquid; a gas enriched in argon relative to the air is withdrawn from the second column; at least a portion of the oxygen-enriched liquid is vaporized by heat exchange with the argon-enriched gas; and the vaporized, oxygen-enriched liquid is sent to an intermediate level of the second column.

Certain embodiments of the present invention lies in providing a high-purity oxygen production system which is capable of supplying liquid nitrogen in order to supply the cold required by a high-purity oxygen production apparatus, without the use of a costly conventional liquefaction apparatus.

A high-purity oxygen production system in accordance with an embodiment can include: an air separation apparatus including a main heat exchanger, a medium-pressure column and a low-pressure column; and a high-purity oxygen production apparatus including a nitrogen compressor, a nitrogen heat exchanger and at least one (high-purity) oxygen rectification column, an oxygen-containing stream serving as a starting material for high-purity oxygen is supplied from the low-pressure column to the high-purity oxygen production apparatus, and liquid nitrogen obtained from the medium-pressure column is supplied to the high-purity oxygen production apparatus in order to replenish cold heat required for operation of the high-purity oxygen production apparatus.

A method for obtaining an air product in an air separating system in which a liquid fraction is obtained from feed air and used to provide the air product and in which the liquid fraction is temporarily stored in a tank arrangement. A tank arrangement with at least two tanks is used, and the liquid fraction is fed to at least one of the tanks and/or is removed from at least one of the tanks in order to provide the air product. In the process, the liquid fraction is not fed to and removed from any one of the tanks at the same time, and the composition of the liquid fraction in a tank is ascertained prior to each removal of the liquid fraction from the tank. An air separating system is also described.

The method for reducing or removing non-volatile impurities in a high-purity oxygen liquid comprises: an oxygen vaporization step for vaporizing a high-purity oxygen liquid obtained from a high-purity oxygen rectification column in an air separation unit for producing the high-purity oxygen liquid; and an oxygen recondensing step for recondensing oxygen gas vaporized in the oxygen vaporization step. This method may also comprise a high-purity oxygen liquid extraction step for extracting a condensate obtained in the oxygen recondensing step.

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.

A system and method for the production and supply of a densified, liquid oxidant to a space vehicle launch facility is provided. A stream of liquid oxygen taken from a co-located, liquid producing air separation unit is densified in a two refrigeration stage, integrated densification system. The first refrigeration stage is a nitrogen based reverse Brayton cycle refrigeration cycle that provides refrigeration to the second refrigeration stage. The second refrigeration stage is a helium and/or neon comprising refrigerant loop that densifies the liquid oxygen to a temperature between about 70 Kelvin and 57 Kelvin. The integrated densification system may also be configured to densify liquid methane or other propellants used in space vehicle launches.