Method for preparing synthesis gas after pure oxygen catalytic partial oxidation of purge gas in methanol synthesis loop to increase yield of methanol and device

Abstract

The invention discloses a method for preparing synthesis gas after pure oxygen catalytic partial oxidation of purge gas in the methanol synthesis loop to increase yield of methanol, which is characterized in that methane-containing gas is compressed by a synthesis gas compressor, is mixed with recycle gas which exits the methanol synthesis loop and separates the methanol and is compressed and preheated by a recycle compressor, and then the mixed gas enters the methanol synthesis loop to synthesize methanol; the methane-containing gas which exits the methanol synthesis loop is condensed into crude methanol liquid, thus being separated; the purge gas separating the methanol enters a hydrogen recovery device after being washed; and hydrogen rich gas and tail gas are obtained after recovery of the hydrogen recovery device, wherein the hydrogen rich gas returns to be mixed with the methane-containing gas and then enters the synthesis gas compressor or is output as a hydrogen product, and the tail gas is sent to a pure oxygen catalytic partial oxidation device to undergo catalytic oxidation reaction, and the obtained converted gas returns to be mixed with the methane-containing gas and then enters the synthesis gas compressor or the recycle compressor, or is directly sent to the methanol synthesis loop. The invention also discloses a device used in the method.

Description

technical field [0001] The present invention relates to the technical field of comprehensive utilization of coal gasification gas, in particular to a tail gas (waste gas) treatment method and device in a methanol synthesis circuit, and in particular to synthesis gas produced after the exhaust gas of the methanol synthesis circuit is catalyzed and partially oxidized (autothermally converted) by pure oxygen A method and device for increasing methanol production. Background technique [0002] The methane content in the feed gas (fresh synthesis gas) entering the methanol synthesis circuit has obvious differences due to different sources or different coal gas production methods, and may sometimes be very high. For example, the methane content in the acetylene tail gas produced by natural gas can reach 3-4% (V); the methane content in the raw gas after purification of the coal gas produced by using crushed coal as raw material and Lurgi furnace coal gas production can reach 17-20...

AI Technical Summary

Problems solved by technology

This method involves the compression of multiple strands of PSA desorbed gas, such as the compression of CO components and methane components, so there is a serious pressure "high-low disease" and large power consumption; there is also the fluctuation of PSA pressure swing adsorption gas volume, which is harmful to centrifugal The stable operation of the conventional synthesis gas compressor is unfavorable; the PSA recovery efficiency is low, the component separation and cutting are not obvious, and methane still exists in the synthesis gas; moreover, the reliability of the pure oxygen partial oxidation conversion device is reduced before methanol synthesis

In this method, the CO component compressor and the methane component compressor operate in parallel, and then operate in series with the centrifugal syngas compressor, which has poor reliability; two sets of pressure swing adsorption devices operate in series, and problems in the front section cause the latter section to fail to operate, which is reliable. Poor performance; large-scale one-step CO extraction PSA device (greater than 11000Nm3 / h), there is no performance at home and abroad

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