CO2 full capture and H2S enrichment process

Abstract

The invention discloses a CO2 full capture and H2S enrichment process. According to the process, a low-temperature methanol washing process and an acid gas extraction concentration process are effectively combined, and a nitrogen gas extraction system and an H2S enrichment tower are canceled, so that no nitrogen gas consumption is in a running process and the running cost of the process is reduced; finished low-pressure CO2 gas in the low-temperature methanol washing process is fully utilized to cool acid gas, so that the solubility of an MDEA (methyldiethanolamine) solution is improved, at least 5% of MDEA solution circulation volume is reduced, and the energy consumption is lowered; a tail gas washing and discharging system is not configured, no tail gas is generated in the running process, and more than 99.5% of CO2 gas in coarse synthesis gas can be recovered and turned into finished high-concentration CO2 gas, so that the full capture of the CO2 gas is achieved, the volume concentration of the H2S gas in the H2S-rich acid gas is more than 70%, and the full enrichment of the H2S gas is achieved.

Description

technical field [0001] The invention relates to the field of gas purification and recovery, specifically a CO 2 Total capture and H 2 S enrichment process. Background technique [0002] With the rapid development of social economy, the output of industrialization continues to increase. In industrialized production and people's daily life, the use of energy materials such as coal, oil, and natural gas has increased sharply. Along with the combustion of these energy materials, a large amount of CO 2 , while CO 2 The large increase in the global greenhouse effect is becoming more and more serious, therefore, the CO 2 Capture has become a problem that must be solved in the process of social development; in addition to producing a large amount of CO 2 In addition, the gas H that is more harmful to the environment and human health will be produced. 2 S, therefore, it is the unshirkable responsibility of all industries to meet the emission standards of sulfur-containing gases...

AI Technical Summary

Problems solved by technology

[0003] Currently, traditional CO 2 、H 2 The capture of S and other gases is mainly realized through the low-temperature methanol washing process, which mostly realizes the gas capture through decompression flash evaporation, nitrogen stripping, and steam heating. Although the traditional low-temperature methanol washing device is simple in configuration and easy to operate Stable but there are many disadvantages: need to set H 2 S enrichment tower or nitrogen stripping tower needs to consume nitrogen during equipment operation, and the operating cost is relatively high; 2 The recovery rate is less than 50%, most of the CO 2 It is discharged into the air in the form of tail gas, and the gas capture effect is poor; the enriched H during the operation of the equipment 2 The volume concentration of S acid gas is small, which puts forward higher requirements for the subsequent sulfur recovery unit; during operation, methanol will be 2 S acid gas is lost, which increases methanol loss and operating costs

In order to improve the above problems, some manufacturers have also improved the low-temperature methanol washing process. As disclosed in the invention patent "Using Low-Temperature Methanol Solution to Remove Acid Gas" with the Chinese Patent Publication No. CN101874967A, nitrogen stripping-flash evaporation- Nitrogen stripper - the method to capture CO 2 Molar concentration above 90%, H 2 The S molar concentration is above 25%, but due to the need to use nitrogen in the process flow, the process operation cost is relatively high; as the invention patent of CN103157346A, "Low temperature methanol washing and CO 2 Capture Coupling Method and System” discloses that by desorbing the methanol after absorbing the acid gas and desorbing the CO-enriched 2 The exhaust gas is purified, and the purified CO 2 For concentrated capture, the captured CO 2 The volume concentration can reach more than 95%, but because the process requires part of the gas to be vented, and nitrogen and tail gas are used in the process, it is not conducive to the effective utilization of energy and needs further improvement

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