A process for selectively removing hydrogen sulphide relative to carbon dioxide from a gaseous mixture containing at least hydrogen sulphide H.sub.2S and carbon dioxide CO.sub.2, includes a step of contacting the gaseous mixture with an absorbent solution including at least one amine, water, and at least one C.sub.2 to C.sub.4 thioalkanol. A use of the absorbent solution for selectively removing hydrogen sulphide relative to carbon dioxide from a gaseous mixture containing at least hydrogen sulphide and carbon dioxide, is disclosed. Disclosed is a use of at least one C.sub.2 to C.sub.4 thioalkanol as an additive in an absorbent solution including at least one amine, and water, for increasing the selectivity of the absorbent solution for the removal of hydrogen sulphide relative to carbon dioxide from a gaseous mixture containing at least hydrogen sulphide and carbon dioxide.

Disclosed is method for removing carbonyl sulphide and/or carbon disulphide from a sour gas stream. The method comprises subjecting the gas stream to simultaneous contact with an absorption liquid, such as an aqueous amine solution, and with a catalyst suitable for hydrolyzing carbonyl sulphide and/or carbon disulphide. To this end, the invention also provides a reactor system wherein both an absorption liquid and a catalyst are present. In a preferred embodiment, the catalyst is a heterogeneous catalyst present on or in an absorption column, either coated on the trays of a column with trays, or contained in the packing of a packed column.

Disclosed is a system and method of separating and collecting acid gas such as carbon dioxide in which the energy consumption in a stripping column for regenerating an absorbent may be reduced. In the system and method, the energy consumption may be reduced using heat generated during the acidic gas separation and collection processes. In the system and method, a low-temperature condensate from a condenser may be preheated by heat exchange with a high-temperature processed gas, and then supplied into the stripping column, thereby to reduce the heat duty of a reboiler and the energy consumption in the condenser for cooling. A partial flow of a carbon diode-absorbed absorbent from an absorber column may be preheated by heat exchange with high-temperature processed gas from an upper portion of the stripping column, and then supplied into the stripping column, thereby to further reduce the heat duty of the reboiler.

Systems comprising a composition where an imidazole is tethered to an amine and a solvent are described herein. Methods of their preparation and use are also described herein. The methods of using the systems include the reduction of volatile compounds from gas streams and a liquid stream.

The invention relates to a method for cleaning corrosive process gases that contain sulfur compounds. According to the method, a gas stream that contains corrosive gases is conducted, in a sorption phase, over an inorganic sorbent material which absorbs at least one of the sorbable sulfurous components on the sorbent material, and the sulfurous compound-depleted gas stream is removed.

The invention relates to a process and a plant for removing thiols from synthesis gas. Thiols and optionally thiophene and carbon disulfide are absorbed in a dedicated absorption stage with methanol as physical absorption medium. Methanol laden with at least thiols is freed of thiols in a stripping stage with methanol vapours as stripping gas and the methanol vapours-containing thiols are freed of methanol in a scrubbing stage. The process according to the invention minimizes methanol losses and the amounts of coolant required for the process.

Disclosed is method for removing carbonyl sulphide and/or carbon disulphide from a sour gas stream. The method comprises subjecting the gas stream to simultaneous contact with an absorption liquid, such as an aqueous amine solution, and with a catalyst suitable for hydrolyzing carbonyl sulphide and/or carbon disulphide. To this end, the invention also provides a reactor system wherein both an absorption liquid and a catalyst are present. In a preferred embodiment, the catalyst is a heterogeneous catalyst present on or in an absorption column, either coated on the trays of a column with trays, or contained in the packing of a packed column.

The present disclosure relates to systems and methods for separation of sulfurous material(s) from a multi-component feed stream. The systems and methods can comprise contacting the multi-component feed stream with a solvent in a contacting column so that at least a portion of the sulfurous material(s) is transferred from the multi-component feed stream to the solvent. A stream of a substantially purified gas can thus be provided along with a liquid stream comprising at least a majority of the sulfurous material. In particular, the solvent can comprise liquid carbon dioxide, which can be particularly beneficial for removing sulfurous materials from multi-component feed streams.

A process for recovering sulfur and carbon dioxide from a sour gas stream, the process comprising the steps of: providing a sour gas stream to a membrane separation unit, the sour gas stream comprising hydrogen sulfide and carbon dioxide; separating the hydrogen sulfide from the carbon dioxide in the membrane separation unit to obtain a retentate stream and a first permeate stream, wherein the retentate stream comprises hydrogen sulfide, wherein the permeate stream comprises carbon dioxide; introducing the retentate stream to a sulfur recovery unit; processing the retentate stream in the sulfur recovery unit to produce a sulfur stream and a tail gas stream, wherein the sulfur stream comprises liquid sulfur; introducing the permeate stream to an amine absorption unit; and processing the permeate stream in the amine absorption unit to produce an enriched carbon dioxide stream.

A continuous desulfurization process and process system are described for removal of reduced sulfur species at gas stream concentrations in a range of from about 5 to about 5000 ppmv, using fixed beds containing regenerable sorbents, and for regeneration of such regenerable sorbents. The desulfurization removes the reduced sulfur species of hydrogen sulfide, carbonyl sulfide, carbon disulfide, and/or thiols and disulfides with four or less carbon atoms, to ppbv concentrations. In specific disclosed implementations, regenerable metal oxide-based sorbents are integrated along with a functional and effective process to control the regeneration reaction and process while maintaining a stable dynamic sulfur capacity. A membrane-based process and system is described for producing regeneration and purge gas for the desulfurization.