Device and method for treating low-temperature methanol-washing hydrocarbon-containing exhaust gas

Abstract

The invention discloses a device and method for treating low-temperature methanol-washing hydrocarbon-containing exhaust gas, relates to the technical field of coal chemical industry, and involves low-temperature methanol washing. The device includes a coke-oven gas absorption tower, a shift gas absorption tower, a flash column, a carbon dioxide product tower, a hydrogen sulfide concentration tower, a nitrogen stripping tower, a heat regeneration tower, an acid gas separation device, a tail gas water-washing tower and a buffer tank; the upper portion of the flash column is a coke-oven gas treatment section, and the lower portion is a shift gas treatment section; the lower portion of the coke-oven gas absorption tower is connected with the upper portion of flash column, and the coke-oven gas treatment section is connected with the nitrogen stripping tower, the lower portion of the shift gas absorption tower is connected with the lower portion of the flash column, and the shift gas processing section is connected with the carbon dioxide product tower, the hydrogen sulfide concentration tower and the nitrogen stripping tower successively; the nitrogen stripping tower is connected withthe heat regeneration tower, and the heat regeneration tower is connected with the acid gas separation device and the buffer tank. The hydrocarbon-containing flash steam in the coke-oven gas processcan be enriched and recycled, the reuse of waste gas is achieved, and the equipment investment and the operation cost are reduced.

Description

technical field [0001] The invention relates to the technical field of coal chemical industry, relates to low-temperature methanol washing, and in particular to a device and method for treating hydrocarbon-containing exhaust gas from low-temperature methanol washing. Background technique [0002] The low-temperature methanol washing unit processes two streams of raw gas, one is the crude gas produced by coal gasification, the shifted gas after CO shift, and the other is coke oven gas. The low-temperature methanol washing process of crude gas produced by coal gasification is as follows: first, a small stream of methanol is injected into the crude gas shift gas to reduce the dew point of the shift gas, and then enters the shift gas cooler to exchange heat with multiple streams, and then enters the shift gas absorption tower After going through the desulfurization section and decarbonization section in turn, sulfide and CO are removed by low-temperature lean methanol in the tow...

AI Technical Summary

Problems solved by technology

However, due to the CO generated by the water gas and coke oven gas regeneration process 2 The exhaust gas is sent to the exhaust gas washing tower to wash the exhaust gas. Due to the high content of hydrocarbons, there is currently no feasible treatment technology to make the hydrocarbons in the exhaust gas meet the latest environmental protection emission standards.

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