A SPECTRA process for low-temperature fractionation of air, in which bottoms liquid from an additional second rectification column used to obtain oxygen is evaporated in a second condenser-evaporator. In this second condenser-evaporator, gas that has been evaporated beforehand in a first condenser-evaporator, which is used for condensation of tops gas from a first rectification column, is condensed at the pressure level of the previous evaporation. The invention likewise provides a corresponding plant.

The invention proposes a process and an air separation plant comprising a rectification column system comprising a high-pressure column, a low-pressure column, a main heat exchanger, and a main air compressor. The total air supplied to the rectification column system is compressed in the main air compressor to a first pressure level. The high-pressure column is operated at a second pressure level, at least 3 bar below the first pressure level. A gaseous, nitrogen-rich fluid is removed from the high-pressure column and warmed up in the gaseous state without prior liquefaction. A first partial quantity of the gaseous, nitrogen-rich fluid is warmed to a first temperature level of −150 to −100° C., supplied at this first temperature level to a booster and compressed further to a third pressure level. The first partial quantity is then warmed to a second temperature level and discharged from the air separation plant.

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.

Method for separating air by cryogenic distillation, wherein at least part of the air to be distilled is boosted in an air booster, compressed air is allowed to expand in at least one expansion turbine and, if the pressure drop between two points of the booster passes under a threshold and/or a flow of the booster passes under a minimum flow of the booster, part of the air boosted in the booster is allowed to expand without having been cooled between the booster and the expansion turbine and the boosted expanded air is sent upstream or downstream of the at least one turbine, without having been cooled in the heat exchanger, after having been boosted.

An apparatus and process for the compression, expansion, evaporation, and liquefaction of gases or gaseous mixtures consisting of a gas liquefaction column comprising successive chambers made of balloons resembling those used in pneumatic suspensions, and double-piston bases in between the upper and lower end of each chamber. Some of the double-piston bases are fixed while others in between are mobile. The group of mobile double-piston bases is activated in a linear to-and-fro vertical stroke while the other group of double-piston bases remains stationary. This results in consecutive suction and compression of the chambers, creating a Joule-Thomson effect at each of them. This results in the cooling and liquefaction of the gas or gaseous mixture. The apparatus also comprises humidity extractors, and different types of valves and piping.

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 method for separating air by cryogenic distillation, wherein air is compressed in a first compressor, cooled in a heat exchanger and then separated in a system of columns, liquid oxygen is vaporized in the heat exchanger countercurrent to a flow of pressurized gas which pseudo-condenses, a flow of gas which is air or a gas delivered from the system of columns is expanded in a cryogenic expansion turbine having a single wheel, the turbine having an inlet temperature lower than 100 C., a gas which is air or a gas delivered from the system of columns is compressed in a first booster compressor having a single wheel, with an inlet temperature higher than 50 C., a gas which is air or a gas delivered from the system of columns.

Method for separating air by cryogenic distillation, wherein air is compressed in a compressor and is subsequently sent to a heat exchanger, with the air cooled in the exchanger being sent to a check valve downstream of the heat exchanger and subsequently to a turbine, the valve being positioned so that air from a short-circuiting duct cannot return to the exchanger from the compressor.

A gas production system that can supply liquefied gas obtained by rectifying source gas as product gas continuously with high heat efficiency without using a machine that has a risk of contamination like a pump. A gas production system includes a single pressure device having a single pressurized container to which liquefied gas extracted from a rectification unit is supplied, a pressure line for extracting and vaporizing a part of the liquefied gas in the pressurized container and returning the part of the liquefied gas to the pressurized container, and a second heat exchange unit that is disposed in the pressure line, and a liquefied gas storage unit that stores liquefied gas which is led out from the pressurized container.

An apparatus and process for the compression, expansion, evaporation, and liquefaction of gases or gaseous mixtures consisting of a gas liquefaction column comprising successive chambers made of balloons resembling those used in pneumatic suspensions, and double-piston bases in between the upper and lower end of each chamber. Some of the double-piston bases are fixed while others in between are mobile. The group of mobile double-piston bases is activated in a linear to-and-fro vertical stroke while the other group of double-piston bases remains stationary. This results in consecutive suction and compression of the chambers, creating a Joule-Thomson effect at each of them. This results in the cooling and liquefaction of the gas or gaseous mixture. The apparatus also comprises humidity extractors, and different types of valves and piping.