Method suitable for controlling concentration of hydrogen sulfide tail gas in low-temperature methanol washing process

Abstract

The invention discloses a method suitable for controlling the concentration of hydrogen sulfide tail gas in a low-temperature methanol washing process. The method comprises the steps that a sulfur-bearing methanol rich solution dissolved with sulfide and carbon dioxide is subjected to flash evaporation via a medium-pressure flash evaporation tower; fuel gas such as CH4, CO and H2 dissolved in the solution is desorbed and recovered; the methanol solution after the flash evaporation is subjected to pressure reduction and gas stripping to allow a carbon dioxide component to be desorbed from the solution; sulfide is still dissolved in the methanol solution via secondary washing and absorption of the solution to achieve sulfide enrichment; the sulfur-bearing methanol rich solution is heated and then subjected to the flash evaporation; flash evaporation gas returns to a secondary absorption tower to strengthen the sulfide enrichment; the obtained sulfur-bearing methanol solution enters a heat regeneration tower to allow sulfide and residual CO2 to be fully desorbed by the action of steam stripping of methanol steam; and non-condensable gas, namely the acid sulfide tail gas is obtained by further condensation and cooling via a tail gas heat exchanger and a hydrogen sulfide tail gas chiller. The method has the advantages that the method is energy-saving and consumption-reducing, and can adapt to different sulfur recovery technology requirements.

Description

technical field [0001] The invention relates to a method suitable for controlling the concentration of hydrogen sulfide tail gas in the low-temperature methanol washing process. Background technique [0002] Low-temperature methanol washing process is widely used for desulfurization and decarbonation gas removal in the chemical production process. During the low-temperature methanol washing purification process, impurity components such as carbon dioxide and hydrogen sulfide in the raw process gas are washed and absorbed by methanol solvent to be removed. In addition to clean. The purified process gas is used in the post-process production, and the methanol solution that has absorbed impurity components such as carbon dioxide and hydrogen sulfide is recycled after decompression flashing, gas stripping, thermal regeneration and other regeneration processes, during which carbon dioxide is generated , sulfide exhaust tail gas, the acid tail gas containing hydrogen sulfide comp...

AI Technical Summary

Problems solved by technology

The purified process gas is used in the post-process production, and the methanol solution that has absorbed impurity components such as carbon dioxide and hydrogen sulfide is recycled after decompression flashing, gas stripping, thermal regeneration and other regeneration processes, during which carbon dioxide is generated , sulfide exhaust tail gas, the acid tail gas containing hydrogen sulfide components should also be equipped with a sulfur recovery device to meet environmental protection requirements and recover sulfur or sulfuric acid and other by-products, but different sulfur recovery technologies have different requirements for the concentration of hydrogen sulfide in the tail gas , especially when the sulfur content in the raw gas varies greatly, fluctuations in the concentration of hydrogen sulfide in the sour tail gas will adversely affect the sulfur recovery operation

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