Natural gas desulfurization process

Abstract

A natural gas desulfurization process comprises the steps of conducting gas-liquid separation on natural gas containing sulfur, mixing the natural gas containing sulfur with alkali liquid, then conducting gas-liquid separation, enabling the separated natural gas to be subjected to pre-desulfurization to enter a fiber membrane desulfurization reactor D, reacting the natural gas to be subjected to pre-desulfurization with fresh alkali liquid and the alkali liquid obtained from a circulation pump II (F) to remove sulfur, separating a small amount of liquid drops carried by natural gas which is qualified in desulfurization through a purified gas separator, then metering and outputting; circulating the alkali liquid, conducting flash evaporation on part of alkali liquid, driving a gas phase obtained by flash evaporation to enter a mercaptan removing system, and recovering sodium sulphide through a liquid phase; adding a small amount of air into flash steam, enabling the flash steam together with the fresh alkali liquid added with a catalyst and circulation alkali liquid to enter from the upper end of a fiber film mercaptan removing reactor G, oxidizing mercaptan into disulphide through air (oxygen) due to the mercaptan sodium salt generated by being absorbed by sodium hydroxide alkali liquid under the action of the catalyst, then recovering the disulphide, recycling the disulphide and sodium hydroxide, and enabling the purified gas phase to enter a tail gas recovering system. According to the natural gas desulfurization process, the purified gas reaches the standard, the tail gas reaches the standard, and the natural gas desulfurization process is environment-friendly.

Description

technical field [0001] The invention relates to the desulfurization technology of natural gas and synthesis gas. Background technique [0002] The purpose of natural gas (synthesis gas) purification is to remove H from sulfur-containing natural gas (synthesis gas) 2 S, CO 2 , moisture and other impurities (such as organic sulfur, etc.), so that the gas quality of the purified natural gas meets the quality indicators of natural gas transported by pipeline. Provide users with standard purified gas. The national standard requirements for natural gas promulgated by the State Bureau of Quality and Technical Supervision: Class I gas H 2 S≤6 mg / m3, total sulfur≤100mg / m3; Class II gas H 2 S ≤ 20 mg / m3, total sulfur ≤ 200 mg / m3; and it is a mandatory standard. On the other hand, the National Environmental Protection Agency has formulated a comprehensive emission standard for air pollutants. 2 In addition to limiting the emission rate, the emission also has strict regulations on...

AI Technical Summary

Problems solved by technology

And because of the sulfur plugging caused by the solid phase sulfur in the solution, corrosion-abrasion will cause a series of difficult operation problems

At present, there are few successful cases directly used in natural gas desulfurization

Images