Procedure for removing water and petrol from a gas using two additional solvent regeneration steps

摘要

The treatment of a gas containing methane and water and at least one hydrocarbon higher than methane to remove these impurities comprises: (a) separation of the gas to be treated into separate flows (1, 2); (b) contact of flow (2) with a recycled liquid phase containing water and a solvent, where the solvent comprises a non-hydrocarbon liquid organic compound, at least partially miscible with water and distillable at a lower temperature, to give a liquid aqueous phase depleted in solvent (compared to the recycled fluid) and a gaseous phase charged with solvent; (c) separation of the two phases; (d) contacting the solvent-depleted liquid phase with the gas flow (1), free of solvent, in a contact zone (G1), the solvent being extracted from this phase by the gas, providing a gaseous phase rich in solvent and an aqueous regenerated liquid; (e) mixing the gaseous phase from (d) either with the solvent-charged gaseous phase from (b) or with the gas flow (2), free of solvent, of stage (a); (f) cooling the gaseous mixture to partially condense out an aqueous phase and hydrocarbon phase, both containing solvent, and producing the treated gas free from water and hydrocarbons; (g) separating the phases from (f); and (h) recycling the solvent-enriched aqueous phase to step (b).