Air separation system for generating liquid oxygen and liquid nitrogen

Abstract

This kind of air separation system obtaining liquid oxygen and liquid nitrogen at least includes an air separator mainly consisting of a fractionating tower and at least includes an equipment for recovering cold energy of liquefied natural gas mainly consisting of an liquefied natural gas heat exchanger, which still includes main heat exchanger, liquid-oxygen heat exchanger and liquid-nitrogen liquid air subcooler; oxygen is drawn out from the underpart of the upper column on the fractionating tower, and cools and liquefied in the liquid-oxygen heat exchanger as the liquid oxygen products; after nitrogen from the top of the upper column passes through a liquid-nitrogen liquid air subcooler and is reheated by main heat exchanger, some nitrogen enters into liquefied-natural-gas heat exchanger to recool and exchange heat to become high pressure nitrogen through primary compression and pressurization at least. And through throttling expansion and air-liquid separator, nitrogen and liquid nitrogen participate in recycling and other nitrogen as liquid-nitrogen products; energy consumption is reduced notably after using actually, power consumption which produces liquid oxygen of 1kg is 0.39kwh, while the power consumption of the traditional equal air separator is 1.0 to 1.25kwh, which is 2.4 to 3 times than the separator. And it is easy to popularize and apply.

Description

technical field [0001] The invention relates to an air separation system for recovering the cooling capacity of liquefied natural gas to obtain liquid oxygen and liquid nitrogen, which is suitable for mass production of liquid oxygen, liquid nitrogen and argon fractions, and can greatly reduce the energy consumption of the air separation process. Background technique [0002] The main components of air are nitrogen and oxygen, and it is an inexhaustible source of industrial production of nitrogen and oxygen. Oxygen is mainly used as an oxidant in metallurgy, gas-supporting, medical treatment, wastewater treatment and chemical industry. Nitrogen is mainly used for ammonia synthesis, protective atmosphere for metal heat treatment, inert protective gas in chemical production (pipeline purge when starting and stopping, nitrogen seal for easily oxidized substances, pressing materials), grain storage, fruit preservation and electronic industry, etc. The traditional method of sepa...

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Problems solved by technology

However, the air separation process is usually carried out under low temperature conditions, and the low temperature environment (80 ~ 100K) is obtained by mechanical refrigeration driven by electricity. The generation of these cold quantities requires a large amount of electricity, especially when producing large amounts of liquid oxygen and liquid nitrogen. Energy consumption will increase significantly

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