Method for deoxidizing coal bed gas through centrifugalization at low temperature and high speed

Abstract

The invention discloses a method for deoxidizing coal bed gas through centrifugalization at low temperature and high speed. The method comprises the following steps of: placing a front-stage heat exchanger in a sealed vacuum steel board house; inletting the coal bed gas which contains methane and oxygen into the heat exchanger; exchanging heat between the coal bed gas and nitrogen in turn; after the temperature is reduced, inletting the coal bed gas into a centrifugal separator which is driven through output power of an expansion machine driven by in the way that the high-pressure nitrogen consumes internal energy thereof; and separating the coal bed gas at low temperature and high speed into oxygen and deoxidized coal bed gas with methane as the main component, wherein the separated oxygen is exhausted into air, the deoxidized coal bed gas sequentially passes through a rear-stage heat exchanger and exchanges heat with the expanded and cooled nitrogen in the expansion machine, a throttle valve is connected between a fourth heat exchanger and a fifth heat exchanger to throttle the nitrogen and reduce the temperature of the nitrogen, the nitrogen with reduced temperature cools the deoxidized coal bed gas into liquid to be stored, and the nitrogen from the fifth heat exchanger flows through each heat exchanger again to exchange heat, then flows through a nitrogen compressor, a water cooler and an oil remover, enters the heat exchangers again to cool gas, so a circulating loop and counterflow heat exchanging are realized.

Description

technical field [0001] In the invention, a low-temperature centrifugal separator is added, and a high-speed rotating expander is used to drive the centrifugal separator, so as to realize the deoxygenation technology of coal bed gas at low temperature. Considering the problem of the explosion limit of methane, the pre-stage heat exchanger is placed in the explosion-proof area to improve safety. Unlike the previous technology of separating coalbed methane by chemical reaction, this invention studies the coalbed methane deoxidation technology from the perspective of mechanical and component physical properties differences The invention belongs to the field of gas deoxygenation, and in particular relates to a deoxidation method in the field of coal bed gas. Background technique [0002] The associated gas adsorbed in coal seams is called coalbed methane, and its main component is methane, which belongs to unconventional natural gas. The world's coalbed methane reserves are huge...

AI Technical Summary

Problems solved by technology

Coke deoxidation and noble metal catalyst catalytic deoxidation can both reduce the oxygen content in coalbed methane to less than 0.5%, which meets the requirements of safe separation. However, the former needs to consume coke resources, and the latter has the disadvantage of noble metal deoxidation because of the price of the catalyst. Expensive, high cost of deoxygenation

These deoxidation methods all consider the deoxidation of coalbed methane from the perspective of chemical reactions, and have the disadvantages of low safety, high cost, low product recovery rate, and high methane loss rate. The present invention proposes a method based on the above background technology. A low-temperature high-speed centrifugal deoxygenation method. A low-temperature centrifugal separator is added to the deoxygenation device, and the oxygen in the coalbed methane is separated at low temperature according to the characteristic that the concentration difference between methane and oxygen becomes larger. In order to improve safety, the front-stage heat exchanger in explosion-proof area

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