Method of extracting the hydrogen sulfide contained in a hydrocarbon gas

A method of extracting the hydrogen sulfide contained in a gas comprising aromatic hydrocarbons, wherein the following stages are carried out:

• a) contacting said gas with an absorbent solution so as to obtain a gas depleted in hydrogen sulfide and an absorbent solution laden with hydrogen sulfide,
• b) heating and expanding the hydrogen sulfide-laden absorbent solution to a predetermined temperature and pressure so as to release a gaseous fraction comprising aromatic hydrocarbons and to obtain an absorbent solution depleted in aromatic hydrocarbons and enriched in carbon dioxide, said temperature and said pressure being so selected that said gaseous fraction comprises at least 50% of the aromatic hydrocarbons contained in said hydrogen sulfide-laden absorbent solution and at most 35% hydrogen sulfide contained in said hydrogen sulfide-laden absorbent solution,
• c) thermally regenerating the absorbent solution depleted in aromatic hydrocarbon compounds so as to release a hydrogen sulfide-rich gaseous effluent and to obtain a regenerated absorbent solution,
• d) treating at least part of the hydrogen sulfide-rich gaseous effluent obtained in stage c) by a Claus process, and
• e) contacting the gaseous fraction comprising aromatic hydrocarbons obtained in stage b), as well as tail gases from said Claus process of stage d), with a second absorbent solution so as to produce a hydrogen sulfide-poor stream and a second absorbent solution enriched in hydrogen sulfide.

A method of extracting the hydrogen sulfide contained in a gas comprising aromatic hydrocarbons, wherein the following stages are carried out:

• a) contacting said gas with an absorbent solution so as to obtain a gas depleted in hydrogen sulfide and an absorbent solution laden with hydrogen sulfide,
• b) heating and expanding the hydrogen sulfide-laden absorbent solution to a predetermined temperature and pressure so as to release a gaseous fraction comprising aromatic hydrocarbons and to obtain an absorbent solution depleted in aromatic hydrocarbons and enriched in carbon dioxide, said temperature and said pressure being so selected that said gaseous fraction comprises at least 50% of the aromatic hydrocarbons contained in said hydrogen sulfide-laden absorbent solution and at most 35% hydrogen sulfide contained in said hydrogen sulfide-laden absorbent solution, and
• c) thermally regenerating the absorbent solution depleted in aromatic hydrocarbon compounds so as to release a hydrogen sulfide-rich gaseous effluent and to obtain a regenerated absorbent solution, wherein the hydrogen sulfide-rich gaseous effluent obtained in stage c) is partly condensed by cooling so as to produce a gas phase and a condensate and wherein, prior to stage c), the absorbent solution depleted in aromatic hydrocarbons is contacted with a fraction of said gas phase so that said fraction carries along part of the aromatic hydrocarbons and of the carbon dioxide contained in said solution.