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an oxygen product using an air separation plant having a distillation column system, in which a cryogenic liquid is withdrawn from the distillation column system, wherein a first portion of the cryogenic liquid is subjected to a pressure-increasing evaporation by evaporating a second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.

An apparatus for the production of air gases with variable liquid production by the cryogenic separation of air can include a cold box having a heat exchanger, and a system of columns; a pressure monitoring device; and a controller. The cold box can be configured to receive a purified and compressed air stream under conditions effective for cryogenically separating the air stream to form an air gas product. The apparatus may also include means for transferring the air gas product from the cold box to an air gas pipeline. The pressure monitoring device is configured to monitor the pipeline pressure, and the controller is configured to adjust the product pressure of the air gas product coming out of the cold box based upon the pipeline pressure and to further adjust liquid production from the cold box based on the adjusted product pressure.

A nitrogen liquefier configured to be integrated with an argon and nitrogen producing cryogenic air separation unit and method of nitrogen liquefaction are provided. The integrated nitrogen liquefier and associated methods may be operated in at least three distinct modes including: (i) a nil liquid nitrogen mode; (ii) a low liquid nitrogen mode; and (iii) a high liquid nitrogen mode. The present systems and methods are further characterized in an oxygen enriched stream from the lower pressure column of the air separation unit is an oxygen enriched condensing medium used in the argon condenser.

A nitrogen liquefier configured to be integrated with an argon and nitrogen producing cryogenic air separation unit and method of nitrogen liquefaction are provided. The integrated nitrogen liquefier and associated methods may be operated in at least three distinct modes including: (i) a nil liquid nitrogen mode; (ii) a low liquid nitrogen mode; and (iii) a high liquid nitrogen mode. The present systems and methods are further characterized in an oxygen enriched stream from the lower pressure column of the air separation unit is an oxygen enriched condensing medium used in the argon condenser.

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.

One object of the present invention is to provide a multistage bath condenser-reboiler capable of suppressing a decrease in condensation efficiency and making it compact. The present invention provides a multistage bath condenser-reboiler, including: a heat exchange core including a heat exchange section formed by adjacently stacking an evaporation passage through which liquid to be evaporated flows, and which is partitioned into a plurality of stages, and a condensation passage through which gas is condensed by heat exchange with the liquid; a liquid reservoir which is configured to store liquid which is supplied into the evaporation passage or flowed out from the evaporation passage; and a liquid communication passage which is configured to flow the liquid in the liquid reservoir from an upper liquid reservoir into a lower liquid reservoir; and the liquid reservoir is provided for each evaporation passage partitioned into the plurality of stages on at least one side surface in a width direction of the heat exchanger core, which is orthogonal to a stacking direction of the condensation passage and the evaporation passage, wherein the condensation passage is divided at least two stages, and wherein the multistage bath condenser-reboiler further comprises: a gas header which is provided at the top of each stage of the condensation passage to supply the gas into the condensation passage of each stage; condensation inlet flow channels which introduce the gas supplied in the gas header into the condensation passage; a liquid header which is provided at the bottom of each stage of the condensation passage, and collects liquid generated by condensation of the gas in the condensation passage, and condensation outlet flow channels which flow out the liquid generated by condensation into the liquid header.

A method for cryogenic separation of air uses an air separation plant, wherein, in a mass transfer column, a liquid first fluid and a gaseous second fluid are subjected to mass transfer with one another. A gaseous third fluid is removed from the column and is at least partly discharged from the air separation plant. A liquid fourth fluid is removed from the column and is at least partly fed into a low-pressure column. The first fluid is formed using at least a part of an oxygen-rich liquid removed from the low-pressure column. The second fluid is formed using an oxygen-enriched liquid removed from a high-pressure column. The oxygen-enriched liquid removed from the high-pressure column and bottom liquid of the mass transfer column are mixed and partly evaporated in a condenser-evaporator. A liquid fifth fluid is removed from the mass transfer column between a feed point for the first fluid and a feed point for the oxygen-enriched liquid, and is at least partly fed into the low-pressure column. The fifth fluid or a fraction thereof is fed into the low-pressure column below the fourth fluid or a fraction thereof.

A nitrogen liquefier configured to be integrated with an argon and nitrogen producing cryogenic air separation unit and method of nitrogen liquefaction are provided. The integrated nitrogen liquefier and associated methods may be operated in at least three distinct modes including: (i) a nil liquid nitrogen mode; (ii) a low liquid nitrogen mode; and (iii) a high liquid nitrogen mode. The present systems and methods are further characterized in an oxygen enriched stream from the lower pressure column of the air separation unit is an oxygen enriched condensing medium used in the argon condenser.

A method for starting up an air separation plant having a higher-pressure column, a lower-pressure column, and a falling film vaporizer disposed within a lower section of the lower-pressure column is provided. The method can include the steps of: introducing a cooled and compressed air stream into the higher pressure column; withdrawing an oxygen-enriched liquid stream from a bottom section of the higher-pressure column and introducing said oxygen-enriched liquid stream to an upper section of the lower-pressure column; and exchanging heat between nitrogen gas coming from a top section of the higher-pressure column and liquid oxygen from the lower-pressure column within the falling film vaporizer. During a start-up period, flow of liquid oxygen is at least reduced to the closed core. This reduces the available heat exchange area during start up, which increases ΔT and ΔP in the condenser/reboiler.

A liquefier device which may be a retrofit to an air separation plant or utilized as part of a new design. The flow needed for the liquefier comes from an air separation plant running in a maxim oxygen state, in a stable mode. The three gas flows are low pressure oxygen, low pressure nitrogen, and higher pressure nitrogen. All of the flows are found on the side of the main heat exchanger with a temperature of about 37 degrees Fahrenheit. All of the gasses put into the liquefier come out as a subcooled liquid, for storage or return to the air separation plant. This new liquefier does not include a front end electrical compressor, and will take a self produced liquid nitrogen, pump it up to a runnable 420 psig pressure, and with the use of turbines, condensers, flash pots, and multi pass heat exchangers. The liquefier will make liquid from a planned amount of any pure gas oxygen or nitrogen an air separation plant can produce.