A mixed salt composition adapted for use as a sorbent for carbon dioxide removal from a gaseous stream is provided, the composition being in solid form and including magnesium oxide, an alkali metal carbonate, and an alkali metal nitrate, wherein the composition has a molar excess of magnesium characterized by a Mg:X atomic ratio of at least about 3:1, wherein X is the alkali metal. A process for preparing the mixed salt is also provided, the process including mixing a magnesium salt with a solution comprising alkali metal ions, carbonate ions, and nitrate ions to form a slurry or colloid including a solid mixed salt including magnesium carbonate; separating the solid mixed salt from the slurry or colloid to form a wet cake; drying the wet cake to form a dry cake including the solid mixed salt; and calcining the dry cake to form a mixed salt sorbent.

A method for treating a synthesis gas from a gasification step. The synthesis gas is cooled to condense heavy organic impurities and water. At the end of the cooling step, light organic impurities and inorganic impurities are adsorped by at least one adsorption bed. The water and heavy tars are separated by decantation from the step of cooling the synthesis gas. At least one adsorption bed is regenerated by temperature-modulated or pressure-modulated desorption.

A method for treating a synthesis gas from a gasification step. The synthesis gas is cooled to condense heavy organic impurities and water. At the end of the cooling step, light organic impurities and inorganic impurities are adsorped by at least one adsorption bed. The water and heavy tars are separated by decantation from the step of cooling the synthesis gas. At least one adsorption bed is regenerated by temperature-modulated or pressure-modulated desorption.

A mixed salt composition adapted for use as a sorbent for carbon dioxide removal from a gaseous stream is provided, the composition being in solid form and including magnesium oxide, an alkali metal carbonate, and an alkali metal nitrate, wherein the composition has a molar excess of magnesium characterized by a Mg:X atomic ratio of at least about 3:1, wherein X is the alkali metal. A process for preparing the mixed salt is also provided, the process including mixing a magnesium salt with a solution comprising alkali metal ions, carbonate ions, and nitrate ions to form a slurry or colloid including a solid mixed salt including magnesium carbonate; separating the solid mixed salt from the slurry or colloid to form a wet cake; drying the wet cake to form a dry cake including the solid mixed salt; and calcining the dry cake to form a mixed salt sorbent.

A system and method for improving the quality of a raw gas or raw syngas passes the raw gas or raw syngas past a catalytic element comprising catalyst with an optional sorbent. A downstream measurement of one or more parameters of the improved gas is fed back to a controller configured to regulate the regeneration of the catalyst and optional sorbent and, optionally, the flow rate of the regeneration fluid to the catalytic element. The system and method are particularly suitable for improving raw syngas generated from a carbonaceous material in a fixed bed or fluidized-bed or entrained-flow gasifier. One or more undesirable syngas constituents are subject to one or more of catalytic cracking, reforming, partial oxidation and/or decomposition to promote their conversion into desirable syngas constituents. At least one catalytic element is regenerated in situ, either periodically, continuously, or in a combination of these two modes.

A system and method for improving the quality of a raw gas or raw syngas passes the raw gas or raw syngas past a catalytic element comprising catalyst with an optional sorbent. A downstream measurement of one or more parameters of the improved gas is fed back to a controller configured to regulate the regeneration of the catalyst and optional sorbent and, optionally, the flow rate of the regeneration fluid to the catalytic element. The system and method are particularly suitable for improving raw syngas generated from a carbonaceous material in a fixed bed or fluidized-bed or entrained-flow gasifier. One or more undesirable syngas constituents are subject to one or more of catalytic cracking, reforming, partial oxidation and/or decomposition to promote their conversion into desirable syngas constituents. At least one catalytic element is regenerated in situ, either periodically, continuously, or in a combination of these two modes.

A method for treating a synthesis gas from a gasification step. The synthesis gas is cooled to condense heavy organic impurities and water. At the end of the cooling step, light organic impurities and inorganic impurities are adsorped by at least one adsorption bed. The water and heavy tars are separated by decantation from the step of cooling the synthesis gas. At least one adsorption bed is regenerated by temperature-modulated or pressure-modulated desorption.

A method for treating a synthesis gas from a gasification step. The synthesis gas is cooled to condense heavy organic impurities and water. At the end of the cooling step, light organic impurities and inorganic impurities are adsorped by at least one adsorption bed. The water and heavy tars are separated by decantation from the step of cooling the synthesis gas. At least one adsorption bed is regenerated by temperature-modulated or pressure-modulated desorption.

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.

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.