A method for desulfurization and light hydrocarbon removal from natural gas by using ionic liquid

Abstract

The invention discloses a method for desulfurizing and removing light hydrocarbons from natural gas by using ionic liquids. Firstly, ionic liquids or mixed solvents of ionic liquids and molecular solvents are used as absorbents to contact natural gas to absorb sulfides, light hydrocarbons and carbon dioxide in natural gas. , to obtain the absorption liquid and the remaining tail gas; the light hydrocarbon mainly contains C 2 ~C 4 Alkanes or alkenes; and then the absorption liquid is desorbed in two stages, and the light hydrocarbons and sulfides are desorbed in turn, and the absorbent obtained by desorption is recycled. The invention provides a method for removing sulfur and light hydrocarbons from natural gas by using ionic liquid or a mixed solvent composed of ionic liquid and molecular solvent as absorbent. The designed ionic liquids with long alkyl side chains in the anions have high selective solubility of hydrogen sulfide, light hydrocarbons and other gases, which are superior to conventional ionic liquids, thus achieving efficient removal of sulfides and recovery of light hydrocarbons.

Description

technical field

[0001] The invention relates to the field of separation and purification of natural gas, in particular to a method for desulfurizing and delighting hydrocarbons from natural gas by using ionic liquid. Background technique

[0002] As an important resource material, natural gas is also a particularly important basic raw material gas in the chemical industry. Due to the needs of some downstream processes and the recovery and utilization of resources, it is necessary to desulfurize natural gas and recover light hydrocarbons. At present, the absorption method is mostly used for desulfurization and light hydrocarbon removal in natural gas.

[0003] The Chinese patent document with publication number CN101016492A discloses a low-temperature methanol washing process for decarbonization and desulfurization of natural gas raw material gas. Full contact, the hydrogen sulfide and carbon dioxide in the feed gas are absorbed by lean methanol, and the methanol-rich liqui...