A process and system for preparing sodium hydrosulfide from acid gas

Abstract

The invention discloses a process and system for producing sodium hydrosulfide from acidic gas. The process employs a gas-liquid two-phase countercurrent absorption reaction and uses a NaOH solution as an absorption liquid to treat acidic gases so as to produce NaHS. According to the process, a primary liquid reaction product is circulated to a secondary intermediate tank and used as a diluent; and a supplementary carrier gas pipeline is arranged to introduce supplementary carrier gas, so the concentration of CO2 in the acidic gases is reduced and most CO2 is taken out of the apparatus together with the carrier gas, thereby realizing control of the contents of Na2CO3 and NaHCO3, preventing obstruction of the pipelines due to crystallization caused by production of a great amount of Na2CO3 and guaranteeing long cycle operation of an apparatus. The acidic gas treating process provided by the invention is simple and can achieve the dual objectives of purification of acidic gas and reclamation of pollutants; and the system for producing sodium hydrosulfide from acidic gas has the advantages of small scale, low energy consumption and low proneness to obstruction.

Description

technical field [0001] The invention relates to a process and system for preparing sodium hydrosulfide from acid gas, which belongs to the field of acid gas purification, and in particular to a treatment method and device suitable for purification of acid gas containing hydrogen sulfide and recycling of pollutants. Background technique [0002] Refinery acid gas mainly comes from sour water stripping, circulating hydrogen desulfurization, dry gas desulfurization and other devices. The acid gas mainly contains H 2 S, CO 2 . At present, the acid gas in most small refineries basically adopts the treatment method of post-combustion emission. On the one hand, this method causes a waste of resources, on the other hand, it brings huge pressure to environmental protection and affects the development space of enterprises. In order to protect the environment and ensure the full utilization of resources, it is imperative to recycle the acid gas from small refineries. [0003] The t...

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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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