Method for increasing concentrations of acid gas hydrogen sulfide and carbonyl sulfide in low-temperature methanol washing process

Abstract

The invention relates to a method for increasing concentrations of acid gas hydrogen sulfide and carbonyl sulfide in a low-temperature methanol washing process. The method comprises the following steps: (1) conducting heat exchange cooling and deamination on transforming gas from carbon monoxide conversion, sending the gas from the bottom of a methanol absorbing tower, and passing the gas a the desulfurization segment and a decarbonization segment; (2) after the decarburization segment and desulfurization segment, sending the methanol solution into an intermediate pressure flash column, conducting vacuum flash to emit carbon monoxide and hydrogen in the methanol solution, and the sending into a re-absorbing tower; (3) removing carbon dioxide in the methanol solution in the re-absorbing tower, and sending the sulfur-rich methanol solution discharged from the bottom of the re-absorbing tower to a thermal regeneration tower by a pump; and (4) removing hydrogen sulfide and carbonyl sulfide in the methanol solution in the thermal regeneration tower. The low-temperature methanol washing process is employed to optimize the operation process, and increase the operating efficiency of a subsequent sulfur recovery section. Meanwhile, the method is simple and feasible in the daily operation and increases the economic efficiency for enterprises.

Description

technical field [0001] The invention relates to a method for increasing the concentration of acid gas hydrogen sulfide and carbonyl sulfide in a low-temperature methanol washing process, in particular to a device for washing acid gas with low hydrogen sulfide concentration in the Lurgi low-temperature methanol process. Background technique [0002] The low-temperature methanol washing process has been widely used in gas purification processes and devices such as synthetic methanol, coal-to-oil and other oxo synthesis, and natural gas desulfurization. Low-temperature methanol washing uses methanol as an absorbent to absorb acid gases such as carbon dioxide, hydrogen sulfide, and carbonyl sulfide in the mixed gas, and then decompresses desorption, gas lift separation, and heating desorption to separate methanol from acid gases to achieve acid gas extraction and purification. Mixed gas and recycling purposes for methanol. [0003] At present, in the gas purification devices of...

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Problems solved by technology

Because the acid gas is sent to the sulfur recovery system for environmental protection treatment, in the combustion furnace treatment process using the once-through method, if the acid gas concentration is lower than 45%, the temperature of the combustion furnace cannot reach the minimum temperature of 930°C for stable combustion. The process of the combustion furnace The situation will not be stable, and the sulfur recovery rate will drop, which will easily cause serious environmental protection accidents where sulfur dioxide in the exhaust gas exceeds the standard.

If the split-flow combustion furnace treatment process is used instead of the direct-flow method, although the acid gas concentration is not high, it is necessary to increase the expensive ratio split flow adjustment equipment, and at the same time increase the steam heating equipment to heat the acid gas to increase the temperature of the combustion furnace

And because part of the acid gas in the shunt method needs to be added into the furnace at the part with the highest temperature of the furnace body, it is very easy to cause the refractory material to wash off and cause damage to the furnace body. From the above analysis, it is also difficult to use the shunt method to replace the direct current method. Stability, large investment in transformation, short service life of equipment, etc.

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