External cooling type low pure oxygen air separation system and method

Abstract

The invention provides an external cooling type low pure oxygen air separation system and method. The external cooling type low pure oxygen air separation system comprises a lower tower, a condensing evaporator, an oxygen inlet, an oxygen heat exchanger, a nitrogen heat exchanger, a throttle valve and a delivery pipeline; the condensing evaporator is arranged at the top of the lower tower; the throttle valve is arranged on an outer side of the lower tower; liquid oxygen is fed into the condensing evaporator through the oxygen inlet; raw material air is precooled by the heat exchanger to reach a saturation temperature before going into the bottom of the lower tower, and nitrogen in the raw material air rises to the top of the lower tower and goes into the condensing evaporator; one part of the nitrogen exchanges heat with the liquid oxygen in the condensing evaporator and thus is condensed into liquid nitrogen for flowing black, while the other part of the nitrogen is discharged out of the condensing evaporator and reheated by the nitrogen heat exchanger to reach a normal temperature before being recovered; the liquid oxygen is transformed into oxygen that is discharged out of the condensing evaporator and reheated by the oxygen heat exchanger to reach the normal temperature before being recovered; the liquid oxygen staying at the bottom of the lower tower is discharged out of the lower tower and delivered into the condensing evaporator at the top of the lower tower through the delivery pipeline with the throttle valve to serve as a cold source taking part in the heat exchange process.

Description

technical field [0001] The invention belongs to the field of air separation, and in particular relates to an external cooling type low-purity oxygen air separation system and method. Background technique [0002] Oxygen is widely used in industrial production and daily life. Air contains 21% (volume concentration) of oxygen, which is the cheapest raw material for oxygen production. Therefore, oxygen is generally produced by air separation. [0003] There are many ways to produce oxygen in industry, and the common ones are electrolysis of water (to produce hydrogen and oxygen at the same time) and separation of air to produce oxygen. Oxygen production by electrolysis of water consumes a lot of electricity, so it is only considered for comprehensive utilization in enterprises that use hydrogen. There are two separation methods for air separation oxygen production, one is full low-pressure adsorption process, and the other is deep freezing method to separate air and produce o...

AI Technical Summary

Problems solved by technology

[0006] It can be seen from the above scheme that the installation and equipment settings are still relatively complicated, and the energy consumption is relatively large

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