US 7,459,011 B2Granted

Method for processing a natural gas with extraction of the solvent contained in the acid gases

AssigneeInstitut Francais du Petrole

InventorsRenaud Cadours, Fabrice Lecomte, Lionel Magna, Cécile Barrere-Tricca

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Abstract

The natural gas arriving through pipe 1 is deacidified by being brought into contact with a solvent in zone C. The solvent charged with acid compounds is regenerated in zone R. The acid gases, released into pipe 5 upon regeneration, include a quantity of solvent. The method enables the solvent contained in the acid gases to be extracted. In zone ZA, the acid gases are brought into contact with a non-aqueous ionic liquid whose general formula is Q+ A−, where Q+ designates an ammonium, phosphonium, and/or sulfonium cation, and A− designates an anion able to form a liquid salt. The solvent is removed from the acid gases evacuated through pipe 6. The ionic liquid charged with solvent is regenerated by heating in an evaporator DE. The ionic liquid regenerated is recycled through pipes 8 and 9 to zone ZA. The solvent is evacuated through pipe 13.

Claims10

Dependent claims

Method for processing a natural gas containing at least one of the following acid compounds:

hydrogen sulfide, carbon dioxide, mercaptans, and carbonyl sulfide, where the following steps are taken:
a) the natural gas is brought into contact with a solvent that takes up the acid compounds so as to obtain a purified gas and a solvent charged with acid compounds,
b) the solvent charged with acid compounds is regenerated so as to obtain a regenerated solvent and release a gaseous effluent containing acid compounds and a fraction of solvent,
characterized in that the following steps are carried out:
c) the gaseous effluent is brought into contact with a non-aqueous ionic liquid so as to obtain a gas phase containing acid compounds and an ionic liquid charged with solvent, the general formula of the ionic liquid being Q+ A−, where Q+ designates an ammonium, phosphonium, and/or sulfonium cation, and A− designates an anion able to form a liquid salt, wherein the Q+ cation has one of the following general formulas:
R1R2N+═CR3—R5—R3C═N+R1R2 and R1R2P+═CR3—R5—R3C═P+R1R2 where R1, R2, and R3 represent hydrogen or a hydrocarbyl with 1 to 30 carbon atoms and where R5 represents an alkylene or phenylene residue, and
d) the ionic liquid charged with solvent is regenerated to separate the solvent and recover a solvent-impoverished ionic liquid.

4 more elements

Dependencies are inferred from the claim text.