Method for removing sulfide and light dydrocarbon from natural gas by utilizing ionic liquid

Abstract

The invention discloses a method for removing sulfide and light dydrocarbon from natural gas by utilizing ionic liquid. The method comprises the following steps: taking the ionic liquid or a mixed solvent of the ionic liquid and a molecular solvent as an absorbent to contact with the natural gas and absorb the sulfide, the light dydrocarbon and the carbon dioxide in the natural gas so as to obtain absorption liquid and residual tail gas, wherein the light dydrocarbon is alkane or alkene containing C2-C4; and carrying out two-stage desorption on the absorption liquid so as to desorb the light dydrocarbon and the sulfide in sequence, wherein the absorbent obtained through the desorption is recycled. The method provided by the invention is used for removing the sulfide and the light dydrocarbon from the natural gas by taking the ionic liquid or the mixed solvent of the ionic liquid and the molecular solvent as the absorbent. The designed ionic liquid, the negative ion of which contains a long alkyl side chain, has high selective dissolving capacity for the gas such as hydrogen sulfide and light dydrocarbon and the selective dissolving capacity is superior to that of the conventional ionic liquid, so that the efficient removal of the sulfide and the recovery of the light dydrocarbon are realized.

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...