A multi-stage countercurrent absorption process method and system for acid gas

Abstract

The invention provides a multi-stage countercurrent absorption process and system for acidic gas. The absorption process employs a gas-liquid two-phase countercurrent absorption reaction and uses a NaOH solution as an absorption liquid to treat acidic gas so as to produce NaHS. According to the process, a crystallizer and a separator are arranged in a primary reaction and a secondary reaction, and heat is taken out of a reactor; and through filling of the NaOH solution in stages, peak clipping of reaction heat is realized, and local crystallization caused by generation of heat spots is prevented. A combination of a Venturi reactor and a rotating packed bed reactor is used as a reaction apparatus which is flexible to operate and has high mass transfer efficiency. The acidic gas absorption process provided by the invention is simple and can achieve the dual objectives of purification of acidic gas and reclamation of pollutants; and the acidic gas absorption system has the advantages of small scale, low energy consumption and low proneness to obstruction.

Description

Technical field [0001] The invention provides a process method and system for acid gas multi-stage countercurrent absorption, belonging to the field of acid gas purification, and particularly relates to a treatment method and system suitable for the purification of acid gas containing sulfur hydride and the resource utilization of pollutants. Background technique [0002] Refinery acid gas mainly comes from sour water stripping, circulating hydrogen desulfurization, dry gas desulfurization, etc. The acid gas mainly contains H 2 S, CO 2 . At present, the acid gas of most small refineries basically adopts the treatment method of emissions after combustion. On the one hand, this method causes a waste of resources, on the other hand, it puts huge pressure on environmental protection and affects the development space of enterprises. In order to protect the environment and ensure the full use of resources, it is imperative to recycle the sour gas in small refineries. [0003] The treat...

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Problems solved by technology

[0004] The two-stage Claus + tail gas hydrogenation reduction + solvent absorption technology has mature technology, stable operation, and stable product sulfur quality. However, due to the long process and large investment, the Claus process can only deal with high-concentration acid gases. 2 When the S volume fraction is less than 20%, the device is not easy to operate

This process can only produce 98% industrial sulfuric acid, but cannot produce oleum with higher value. At the same time, due to the difficulty in the transportation and storage of sulfuric acid, the stable market demand near the refinery is an important factor limiting its development.

[0009] CN1836767A discloses a treatment method for sour gas in refineries, utilizing sour gas as the fuel for shaft kilns in cement plants, when the sour gas is burned in the kiln, the H 2 S component reacts chemically with cement material to generate CaSO 4 , other harmful components are also sintered and transformed, which fundamentally solves the problem of acid gas treatment. At the same time, acid gas is used as a gas fuel to make the cement plant energy-saving fuel and achieve the dual purposes of environmental protection and fuel resolution. However, this The method has certain limitations and is not easy to promote

However, the sodium sulfide product of this process is prone to deterioration and is not easy to store

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