Abstract: Method of decarbonating a hydrocarbon gas, a natural gas for example, by washing with a solvent. Said gas is contacted with an absorbent solution so as to obtain a CO2-depleted gas and a CO2-laden absorbent solution. The CO2-laden absorbent solution is then heated and expanded at a predetermined pressure and temperature so as to release a hydrocarbon-containing gaseous fraction and to obtain a hydrocarbon-depleted absorbent solution, said pressure and temperature being so selected that said gaseous fraction comprises at least 50% of the hydrocarbons contained in said CO2-laden absorbent solution and at most 35% of the CO2 contained in said CO2-laden absorbent solution. Finally, the hydrocarbon-depleted absorbent solution is thermally regenerated so as to release a CO2-rich gaseous effluent and to obtain a regenerated absorbent solution.

Abstract: Method of decarbonating a hydrocarbon gas, a natural gas for example, by washing with a solvent. Said gas is contacted with an absorbent solution so as to obtain a CO2-depleted gas and a CO2-laden absorbent solution. The CO2-laden absorbent solution is then heated and expanded at a predetermined pressure and temperature so as to release a hydrocarbon-containing gaseous fraction and to obtain a hydrocarbon-depleted absorbent solution, said pressure and temperature being so selected that said gaseous fraction comprises at least 50% of the hydrocarbons contained in said CO2-laden absorbent solution and at most 35% of the CO2 contained in said CO2-laden absorbent solution. Finally, the hydrocarbon-depleted absorbent solution is thermally regenerated so as to release a CO2-rich gaseous effluent and to obtain a regenerated absorbent solution.

Abstract: The invention is a method for selectively removing hydrogen sulfide H2S from a gaseous effluent comprising at least H2S and CO2. A stage of selective absorption of the hydrogen sulfide in relation to the CO2 is carried out by contacting the effluent with a solution comprising (a) water and (b) at least one nitrogen compound. The compound comprises at least one tertiary amine function or one hindered secondary amine function. The absorption selectivity is controlled by adding (c) a viscosifying compound to the absorbent solution.