A nitrogen producing cryogenic air separation unit with an excess air circuit is provided. The nitrogen producing cryogenic air separation unit is capable of producing high pressure gaseous nitrogen without the use of a nitrogen product compressors and is also capable of producing high rates of liquid nitrogen without adding additional compression stages in the main air compressor and/or without a nitrogen recycle compressor.

A process for producing liquid oxygen, including, a first operating mode, and a second operating mode. During the first operating mode, the distillation column produces a first flowrate of product liquid oxygen, and a first flow rate of liquid nitrogen product. During the second operating mode, the distillation column produces a second flowrate of product liquid oxygen, and a second flow rate of liquid nitrogen product. Wherein, the second flowrate of product liquid oxygen is greater than the first flowrate of product liquid oxygen.

According to the present invention, a method for cryogenic separation of air using an air separation unit comprising a rectification column is provided. Feed air is compressed, cooled and rectified in the rectification column obtaining an overhead gas, wherein a part of the overhead gas of the rectification column is condensed using fluid withdrawn from the rectification column, wherein the condensed overhead gas is used at least in part as a liquid reflux to the rectification column, wherein a first part of the fluid which is used for cooling the overhead gas of the rectification column is, after its use for cooling, compressed and reintroduced into the rectification column, and wherein a second part of the fluid which is used for cooling the overhead gas of the rectification column is, after its use for cooling, expanded and withdrawn from the air separation unit.

An air separation process having a first booster air compressor comprising a first outlet stream and a second booster air compressor comprising a second outlet stream. Wherein the first booster air compressor and the second booster air compressor are in parallel, and the second booster air compressor is driven by a nitrogen turboexpander. The first outlet stream and/or the second outlet stream may be at least partially condensed by heat exchange with a vaporizing low pressure oxygen stream, and the low-pressure gaseous oxygen pressure is in the range of 1.1 bara to 3 bara.

A compressed air stream is cooled in an exchanger to form a compressed cooled air stream. The stream is then cryogenically compressed in a first compressor to form a first pressurized gas stream. The first pressurized gas stream is further cooled in the exchanger, cryogenically compressed in a second compressor, and then it is cooled and partially liquefied. The cooled and partially liquefied product is then fed to a system of distillation columns. A liquid product is removed from the system of distillation columns. This product is then pressurized, vaporized and warmed in the exchanger to yield pressurized gaseous product.

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.

A method and apparatus for producing a high-pressure gas from an air separation unit is provided, in which the method includes the steps of introducing a cold air feed into a distillation column system under conditions effective for separating the cold air feed into a first air gas and a second air gas; withdrawing the first and second air gases from the distillation column system and warming said first and second air gases in a main heat exchanger, wherein the first air gas is withdrawn from the distillation column system at a medium pressure; splitting the first air gas into a first fraction and a second fraction; expanding the first fraction in a turbine; and compressing the second fraction in a booster to a pressure that is higher than the medium pressure, wherein the booster is powered by the turbine

An expander and motor-compressor unit is disclosed. The unit includes a casing and an electric motor arranged in the casing. A compressor is arranged in the casing and drivingly coupled to the electric motor through a central shaft. Furthermore, a turbo-expander is arranged for rotation in the casing and is drivingly coupled to the electric motor and to the compressor through the central shaft.

A system and method for cryogenic air separation arrangement having a booster loaded liquid turbine for expansion of a liquid air stream or other fluid having liquid-like densities is provided. The disclosed booster loaded liquid turbines are relatively small to provide an aerodynamic and speed match between the turbine and the coupled gas compressor. The coupled gas compressor is a supplemental booster compressor and may be a dedicated warm booster compressor or alternatively a cold booster compressor.

A method for obtaining one or more air products, in which method an air fractionation plant is used which has a column system with a pressure column, wherein air is fedto the column system and is fractionated in the column system, wherein at least 90% of the total amount of air supplied to the column system is compressed, wherein nitrogen-rich gas is extracted from the pressure column, and wherein, at least in a first operating mode, further air is compressed to a pressure level above the base pressure level, is expanded, and is warmed without fractionation in the column system. It is provided that, at least in the first operating mode, a proportion of the nitrogen-rich gas extracted from the pressure column is fed to the further air upstream of the expansion.