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.

A supply quantity adjustment device 500 comprises: a total demand quantity calculation unit 502 that calculates a total demand quantity used at a supply destination, based on plant information; an excess/deficit information setting unit 503 that compares the total demand quantity and a flow rate set value and sets a first calculated pressure value; a backup coefficient setting unit that sets a backup coefficient set value based on a reference gasholder pressure, the first calculated pressure value, a reference backup pressure set value, and a measured gasholder pressure value; and a production coefficient setting unit that compares a production pressure set value obtained by adding the reference gasholder pressure and a first pressure output value with the measured gasholder pressure value, and sets a production coefficient so as to modify a variation in the quantity of product gas produced by the air separation apparatus.

A method for reducing heat bumps following regeneration of adsorbers in an air separation unit is provided. The air separation unit can include a front end purification unit, a main air compressor, a main heat exchanger, a distillation column system, a regeneration gas heater, and a regeneration gas cooler, wherein the front end purification unit comprises a first adsorber and a second adsorber. The method can include the steps of: regenerating the first adsorber while the second adsorber operates in an adsorption cycle, wherein the step of regenerating the first adsorber further includes the steps of heating the first adsorber and then cooling the first adsorber, wherein during the step of cooling the first adsorber, a regeneration gas sourced from the distillation column system and cooled in the main heat exchanger is further cooled in a regeneration gas cooler prior to being used to cool the first adsorber.

A method and the apparatus for obtaining a compressed gas product by means of cryogenic separation of air in a distillation column system which has a high-pressure column and a low-pressure column. All of the feed air is compressed in a main air compressor to a first pressure which is at least 4 bar higher than the operating pressure of the high-pressure column. A first partial flow of the feed air compressed in the main air compressor is cooled to an intermediate temperature in a main heat exchanger and is expanded so as to perform work in a first air turbine. At least a first part of the first partial flow expanded so as to perform work is introduced into the distillation column system.

A method for reducing process disturbances during pressurization of an adsorber in an air separation unit is provided, in which the air separation unit includes a front end purification unit and an air buffer tank. In one embodiment, the method can include the steps of: pressurizing a first adsorber while a second adsorber operates in an adsorption cycle, wherein the step of pressurizing the first adsorber further includes the steps of withdrawing a pressurized air stream from the air buffer tank and introducing the pressurized air stream to the first adsorber until the first adsorber is at a target pressure, wherein the air buffer tank is in fluid communication with the booster air compressor, wherein the method further includes the step of continually sending a first portion of air flow from the booster air compressor to the air buffer tank and continually sending a second portion of air flow from the booster air compressor to a system of columns within a cold box for rectification therein.

The present invention discloses a cryogenic rectification process-based method for producing an air product, and an air separation system. By adding an air product outlet line and a liquid air booster pump to an existing cryogenic rectification process apparatus, the existing rectification apparatus is used to prepare oxygen-enriched liquid air by pressurizing, cooling and liquefying feed air; and moreover, a high-pressure or ultra-high-pressure air product can be prepared according to customer requirements by adjusting the ratio of the feed air to the oxygen-enriched liquid air, and pressurizing the mixture to a target pressure by the liquid air booster pump before being vaporized via heat exchange with a gas or liquid product produced by rectification through a heat exchange apparatus. According to the present invention, when gas or liquid products of oxygen and nitrogen are produced by means of rectification, a high-pressure or ultra-high-pressure air product can be provided according to customer requirements, and there is no need to provide an additional air compressor or passively increase the discharge pressure of the air booster, so that the production costs are greatly reduced and the energy efficiency level is improved. The method of the present invention can also improve the stability of devices, especially when a small amount of high-pressure/ultra-high-pressure air product needs to be produced.

A method and a device for producing an air product based on cryogenic rectification; after being cooled by a main heat exchanger, raw material air and nitrogen compressed by means of a compressor are sent to a rectification system for low temperature separation. In the rectification system, products such as oxygen and nitrogen are obtained by means of low temperature separation, and oxygen-enriched liquid air is obtained at or near the bottom of a rectification tower. The oxygen-enriched liquid air or liquid-state air in the rectification system is sent out after being raised to a target pressure by means of a low temperature liquid air pump; air products of various pressures can be produced by means of selecting low temperature liquid air pumps with different lifts or by connecting in series different amounts of low temperature liquid air pumps. The present method can avoid the need to arrange additional air compressors, entirely changing the method for producing medium and high pressure air products in a nitrogen circulation process, and importantly can reduce production costs significantly whilst having greater flexibility. In addition, the present method can increase the oxygen extraction rate of an apparatus, thereby improving the energy efficiency level.

In a method for separating air by cryogenic distillation using a column system consisting of a higher pressure column operating at a first pressure and a lower pressure column operating at a second pressure, a first air flow constituting between 75% and 98% of the air sent to the column system compressed to a third pressure above the first pressure, is sent to the higher pressure column, a second air flow constituting between 5% and 25% of the air sent to the column system is compressed to a fourth pressure above the second pressure but lower than the third pressure, is sent to the lower pressure column, a third column separates an argon-enriched flow and the air sent to the lower pressure column constitutes between 10% and 25% of the total air sent to the column system.

Provided are a method and apparatus for producing nitrogen and oxygen by means of cryogenic distillation of air. Nitrogen products are extracted only from the top of a tower. If a customer needs nitrogen with lower pressure, part of pure nitrogen that is partially located at a first nitrogen product pressure is reheated in a main heat exchanger, then decompressed to a second nitrogen product pressure by means of a nitrogen expander, further reheated by means of the main heat exchanger, and output as a low-pressure nitrogen product. The nitrogen expander can be braked by an expander booster for compressing air. By means of the method, nitrogen with different pressures can be suitably produced, and the energy consumption for producing the pressurized air can be reduced by utilizing the expansion work of nitrogen.

A natural gas power generation process with zero carbon emission is described. The process includes pressurizing air and introducing the pressurized air into an air separation facility to obtain liquid oxygen and liquid nitrogen. The liquid oxygen is used for gasification and power generation The liquid nitrogen is applied as a coolant of flue gas, and then for gasification and power generation.