Expansion refrigeration method for separating coke oven gas by using nitrogen and helium

Abstract

The invention relates to an expansion refrigeration method for separating coke oven gas by using nitrogen and helium. The method comprises the following steps: (1) after compression and precooling ofcoke oven gas, feeding the treated coke oven gas into a first-stage nitrogen cycle expansion refrigeration system, and feeding the treated coke oven gas into a rectification tower through further cooling; (2) after methane exhausted at the bottom of the rectification tower is cooled and liquefied through a second-stage nitrogen cycle expansion refrigeration system, feeding the cooled and liquefiedmethane into a natural gas storage tank for storage, after carrying out first ortho para conversion and second ortho para conversion on hydrogen exhausted at the top of the rectification tower in sequence, feeding the hydrogen into a liquid hydrogen storage tank for storage, wherein cooling capacity is provided by the second-stage nitrogen cycle expansion refrigeration system in the first ortho para conversion process, and cooling capacity is provided by a third-stage nitrogen cycle expansion refrigeration system in the second ortho para conversion process. Compared with the prior art, liquefied natural gas and liquid hydrogen are prepared from the coke oven gas through nitrogen and helium expansion low-temperature cycle, so that the utilization efficiency and energy utilization rate of the coke oven gas are improved, the evacuation phenomenon of the coke oven gas is reduced, and the environmental pollution is little.

Description

technical field [0001] The invention belongs to the technical field of comprehensive utilization of coke oven gas in the coking / steel mill industry, and relates to a method for separating coke oven gas by expanding and cooling nitrogen and helium. Background technique [0002] my country's coke production ranks among the top in the world, with 233 million tons in 2006, 353 million tons in 2009, and 443 million tons in 2012. A large amount of coke oven gas will be produced while coke is produced. If 1t of coke is produced, 430m 3 Calculation of coke oven gas, in 2012, the annual production of coke oven gas in my country reached 190.5 billion m 3 , of which about 70% of the coke oven gas is used for the self-use of enterprises, commercial and urban residents, and the remaining coke oven gas is basically not well utilized, and some are even directly burned and released into the atmosphere. At present, the industrial use of coke oven gas mainly includes: as city gas, power gen...

AI Technical Summary

Problems solved by technology

[0011] The Chinese invention patent with the publication number CN106315510A discloses a coke oven gas hydrogen production process. On the basis of the traditional coke oven gas hydrogen production process, the light hydrocarbon conversion and carbon monoxide medium temperature conversion process are introduced to make the coke oven gas in the raw material Light hydrocarbon components such as methane and ethane and carbon monoxide all participate in the hydrogen production reaction, which can reduce the consumption of raw material gas for hydrogen production, but the process involves chemical conversion process, the stability is difficult to guarantee, and the process is relatively complicated

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