Technique and device for purifying H2S in chemical exhaust gas

Abstract

The invention relates to a technique for purifying H2S in chemical exhaust gas, which comprises the following steps: charging a raw gas enter into a device; drying, filtering and pressurizing, and then charging into a decarburization tower; separating CO2 and N2 from local light dydrocarbon CO2-enriched gas and H2S-enriched solution; throttling and depressurizing the H2S-enriched solution and then charging into a heavy hydrocarbon removing tower; removing majority hydrocarbon in the heavy hydrocarbon removing tower; feeding the pentane and benzene-containing heavy hydrocarbon liquid at higher boiling point acquired at the bottom of the tower into a heavy hydrocarbon storage tank, wherein H2S and propane are the main components at the tower top; reheating the mixed gas at the tower top and then feeding into a MDEA absorbing system for removing propane, thus obtaining H2S gas; drying, thus obtaining the H2S product. The invention also discloses the device for implementing the technique. The invention has the advantages that the effective components in the chemical exhaust gas are separated, the product H2S gas is obtained, and meanwhile, heavy hydrocarbon and high-purity propane gas by-products are obtained, the use ratio of the exhaust gas is increased, the energy is conserved, the emission is reduced, the waste is turned into wealth, all the chemical absorbers are non-toxic and noncombustible, the safety is high and the environment is protected.

Description

technical field [0001] The invention relates to the field of gas purification, in particular to a method for purifying H in industrial tail gas 2 S process and apparatus. Background technique [0002] Hydrogen sulfide is a colorless, toxic gas with the smell of rotten eggs. The hydrogen sulfide gas contained in the chemical tail gas can not only cause poisoning of pipelines and catalysts and deterioration of process conditions, but also cause quite serious environmental pollution and even endanger human survival. Hydrogen sulfide is a valuable raw material in the chemical industry in energy, chemical industry, medicine, agriculture and other aspects. Therefore, rational use of hydrogen sulfide to turn waste into treasure has very important practical significance in actual production. [0003] H from chemical exhaust gas 2 S can be used to produce elemental sulfur by the Claus process, and can also be used as raw material gas for the production of dimethyl disulfide (DMDS...

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Problems solved by technology

[0004] Chinese patent CN201310109589 discloses a treatment method for industrial tail gas containing hydrogen sulfide, which uses chemical methods to use hydrogen sulfide in the tail gas to produce fluorescent grade zinc sulfide powder. This treatment method cannot obtain pure hydrogen sulfide, and there will be about 20% loss of hydrogen sulfide gas

The patent is mainly aimed at the low-temperature methanol washing system for synthetic ammonia, and does not mention the H 2 S tail gas is purified, and methanol is highly toxic. The tail gas washed with low-temperature methanol in natural gas contains more than 5% hydrocarbons. If the method in this patent is used, the hydrocarbons cannot be recovered and the loss is large

Chinese patent 201510376268 discloses a method to increase the concentration of acid gas hydrogen sulfide and carbonyl sulfide in the low-temperature methanol washing process, which is also a method of using methanol absorption, and the concentrated hydrogen sulfide concentration is low, and the highest can only reach 44%

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