A zero-carbon emission process gas purification method and device

Abstract

The invention discloses a zero-carbon emission process gas purification method and device, and belongs to the field of mixed gas purification. The method comprises the steps that tail gas treated by a low-temperature methanol absorption device is conveyed to the lower portion of a separation tank at an inlet, pressurization is conducted through a compressor after separation is conducted, the pressurized tail gas enters the bottom of a CO2 re-absorbing tower and is in counter-current contact absorption with amine liquid on the top, after absorption is conducted, purified gas output from the top of the CO2 re-absorbing tower is conveyed to the bottom of a gas stripping column of the low-temperature methanol absorption device, absorbed absorption liquid conducts heat exchange with absorption liquid in a desorption tower through a heat exchanger, the temperature of the absorption liquid subjected to heat exchange ranges from 75 DEG C to 85 DEG C, the absorption liquid at the temperature is conveyed to the middle of the desorption tower for depressurization, depressurized gas is mixed with bottom steam, flows upwards in the desorption tower and is output from the top of the desorption tower to conduct gas-liquid separation, and therefore CO2 with the concentration of 99% or above is obtained. The zero-carbon emission process gas purification method and device can reduce N2 consumption and desalted water consumption, and energy consumption is reduced by 70%.

Description

technical field [0001] The invention belongs to the field of mixed gas purification, and in particular relates to a zero-carbon emission process gas purification method and device. Background technique [0002] CO and H are removed from the crude gas produced by the coal gasification process 2 , CO 2 In addition, there is a small amount of H 2 Ingredients such as S and COS. The low-temperature methanol washing unit is to remove CO 2 、H 2 S, COS and other acid gases make CO 2 The content can be reduced to 20ppm, and the total sulfur content can be reduced to less than 0.1ppm to meet the requirements of the subsequent production section. The existing low-temperature methanol absorption process is a gas purification process jointly developed by the German Linde Company and Lurgi Company in the early 1950s. The process uses low-temperature methanol as an absorbent, and uses methanol to absorb CO at low temperature. 2 、H 2 S, COS and other acid gases have excellent solub...

AI Technical Summary

Problems solved by technology

[0003] In recent years, with the extensive use of chemical raw materials such as petroleum, coal, and natural gas, the emission of CO in the atmosphere 2 The content of carbon dioxide is increasing year by year, which not only causes serious environmental pollution, but also wastes carbon resources

At present, for large-scale coal-to-synthetic ammonia, synthetic methanol, and coal-to-gas projects, the CO in the low-temperature methanol absorption process is 2 The recovery rate is only about 65%, and the CO in the vented tail gas 2 The content is still as high as 70% or more

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