An air separation device for isobaric separation and production of oxygen and nitrogen

Abstract

An air separation apparatus for isobaric separation and production of oxygen and nitrogen, comprising an air purification apparatus, a pre-cooling system, a distillation system, and a refrigeration replenishment system. Employed at a low-temperature end is a Rankine cycle system that resembles a thermal power cycle apparatus. Employed is a liquid nitrogen wash process. A liquid nitrogen wash refrigeration replenishment system is used to replenish refrigeration for the air separation apparatus. Nitrogen gas (19) from a liquid nitrogen storage tank (18) is introduced into a distillation tower upper tower (10) via a liquid nitrogen pump (20) and a recooler (21). A portion of a cryogenic nitrogen gas (23) coming out from the top part of the upper tower (10) is extracted after being superheated via a main refrigeration exchanger (6) and is returned to the liquid nitrogen storage tank (18) via an expander (25) and the recooler (21), thus implementing isobaric separation of air for production of nitrogen and oxygen. Under the premise of a same refrigeration capacity, this conserves energy by 30% or more compared with a conventional advanced unit, reduces the amount of equipment and materials used, allows for flexible and convenient operation and adjustment, while at the same time allows for multiple pressure levels, for gas supply of multiple gases, and for low energy consumption centralized gas supply.

Description

technical field [0001] The invention relates to an air separation device for isobaric separation and preparation of oxygen and nitrogen, specifically belonging to the technical field of deep freezing. Background technique [0002] The rapid development of the national economy is inseparable from the air separation device. The so-called air separation unit (abbreviated as air separation unit, commonly known as oxygen generator) refers to the use of the principle of deep freezing to liquefy air, and then carry out rectification in the rectification tower according to the difference in boiling point of each component, and finally obtain oxygen, nitrogen, or A device for simultaneously extracting one or several rare gases. [0003] In 1939, Academician Kapitza, a Soviet scientist, invented a high-efficiency (>80%) radial flow centripetal reactionary turboexpander, which created conditions for the birth of a fully low-pressure oxygen machine. The Kapitza turboexpander is the...

AI Technical Summary

Problems solved by technology

[0019] 2) The thermal efficiency of the Carnot cycle can only be less than 1, never equal to 1, because T 1 =∞ or T 2 = 0 is impossible to achieve

[0022] 5) The limit point of the Carnot cycle is the ambient temperature of the atmosphere, and the Carnot cycle does not give a clear answer to the refrigeration process cycle below the ambient temperature

[0024] However, using the basic theory of thermodynamics cannot make a concise, clear and intuitive explanation for the cycle process of the air separation unit.

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