The present invention relates to a process for decomposing calcium sulfide (CaS) into calcium oxide (CaO) and sulfur dioxide (SO.sub.2), comprising:—providing a reactor containing calcium sulfide and a source of carbon,—oxidizing the source of carbon so as to generate carbon dioxide (CO.sub.2),—reacting the calcium sulfide with said carbon dioxide so as to produce carbon oxide (CaO), sulfur dioxide (SO.sub.2) and carbon monoxide (CO) according to the following reaction: CaS+3CO.sub.2˜CaO+SO.sub.2+3CO wherein the oxygen and carbon contents in the oxidation step are chosen such that: (i) the mass ratio C/CaS is comprised between 0.15 and 0.35 and (ii) the mass ratio O.sub.2/C is comprised between 5 and 25.

The present invention relates to a process for decomposing calcium sulfide (CaS) into calcium oxide (CaO) and sulfur dioxide (SO.sub.2), comprising: —providing a reactor containing calcium sulfide and a source of carbon, —oxidizing the source of carbon so as to generate carbon dioxide (CO.sub.2), —reacting the calcium sulfide with said carbon dioxide so as to produce carbon oxide (CaO), sulfur dioxide (SO.sub.2) and carbon monoxide (CO) according to the following reaction: CaS+3CO.sub.2˜CaO+SO.sub.2+3CO wherein the oxygen and carbon contents in the oxidation step are chosen such that: (i) the mass ratio C/CaS is comprised between 0.15 and 0.35 and (ii) the mass ratio O.sub.2/C is comprised between 5 and 25.

A process for recovering sulfur from a tail gas stream comprising the steps of providing a tail gas stream to a chemical looping combustion (CLC) unit, the tail gas stream comprising a sulfide component, providing an oxygen carrier to the CLC unit, the oxygen carrier comprising a calcium carbonate, providing an air stream to the CLC unit, the air stream comprising oxygen, and reacting the sulfide component in the CLC unit with the calcium compound and the air to produce a product effluent, the product effluent comprising calcium sulfate.

A process for recovering sulfur from a tail gas stream comprising the steps of providing a tail gas stream to a chemical looping combustion (CLC) unit, the tail gas stream comprising a sulfide component, providing an oxygen carrier to the CLC unit, the oxygen carrier comprising a calcium carbonate, providing an air stream to the CLC unit, the air stream comprising oxygen, and reacting the sulfide component in the CLC unit with the calcium compound and the air to produce a product effluent, the product effluent comprising calcium sulfate.

A process for recovering sulfur from a tail gas stream comprising the steps of providing a tail gas stream to a chemical looping combustion (CLC) unit, the tail gas stream comprising a sulfide component, providing an oxygen carrier to the CLC unit, the oxygen carrier comprising a calcium carbonate, providing an air stream to the CLC unit, the air stream comprising oxygen, and reacting the sulfide component in the CLC unit with the calcium compound and the air to produce a product effluent, the product effluent comprising calcium sulfate.

A process for recovering sulfur from a tail gas stream comprising the steps of providing a tail gas stream to a chemical looping combustion (CLC) unit, the tail gas stream comprising a sulfide component, providing an oxygen carrier to the CLC unit, the oxygen carrier comprising a calcium carbonate, providing an air stream to the CLC unit, the air stream comprising oxygen, and reacting the sulfide component in the CLC unit with the calcium compound and the air to produce a product effluent, the product effluent comprising calcium sulfate.

Systems and processes for treating acid gas from a sour gas stream are provided. A chemical looping combustion (CLC) process is provided that uses CaCO.sub.3 to capture sulfur from the acid gas and produce CaSO.sub.4. An acid gas treatment unit may receive an acid gas from an acid gas removal unit and produce the CaSO.sub.4 and various gas and air streams for use in heat exchangers for steam production. The acid gas treatment unit may include a fuel reactor, an oxidizer reactor, and a calciner reactor. Another acid gas treatment unit may include a fuel reactor that includes the calciner function and an oxidizer reactor. A selective membrane module may be disposed between the sour gas stream and an acid gas removal unit to produce a H.sub.2S and CO.sub.2 permeate that is mixed with the acid gas stream provided to the acid gas treatment unit.

Systems and processes for treating acid gas from a sour gas stream are provided. A chemical looping combustion (CLC) process is provided that uses CaCO.sub.3 to capture sulfur from the acid gas and produce CaSO.sub.4. An acid gas treatment unit may receive an acid gas from an acid gas removal unit and produce the CaSO.sub.4 and various gas and air streams for use in heat exchangers for steam production. The acid gas treatment unit may include a fuel reactor, an oxidizer reactor, and a calciner reactor. Another acid gas treatment unit may include a fuel reactor that includes the calciner function and an oxidizer reactor. A selective membrane module may be disposed between the sour gas stream and an acid gas removal unit to produce a H.sub.2S and CO.sub.2 permeate that is mixed with the acid gas stream provided to the acid gas treatment unit.

Systems and processes for treating acid gas from a sour gas stream are provided. A chemical looping combustion (CLC) process is provided that uses CaCO.sub.3 to capture sulfur from the acid gas and produce CaSO.sub.4. An acid gas treatment unit may receive an acid gas from an acid gas removal unit and produce the CaSO.sub.4 and various gas and air streams for use in heat exchangers for steam production. The acid gas treatment unit may include a fuel reactor, an oxidizer reactor, and a calciner reactor. Another acid gas treatment unit may include a fuel reactor that includes the calciner function and an oxidizer reactor. A selective membrane module may be disposed between the sour gas stream and an acid gas removal unit to produce a H.sub.2S and CO.sub.2 permeate that is mixed with the acid gas stream provided to the acid gas treatment unit.

Systems and processes for treating acid gas from a sour gas stream are provided. A chemical looping combustion (CLC) process is provided that uses CaCO.sub.3 to capture sulfur from the acid gas and produce CaSO.sub.4. An acid gas treatment unit may receive an acid gas from an acid gas removal unit and produce the CaSO.sub.4 and various gas and air streams for use in heat exchangers for steam production. The acid gas treatment unit may include a fuel reactor, an oxidizer reactor, and a calciner reactor. Another acid gas treatment unit may include a fuel reactor that includes the calciner function and an oxidizer reactor. A selective membrane module may be disposed between the sour gas stream and an acid gas removal unit to produce a H.sub.2S and CO.sub.2 permeate that is mixed with the acid gas stream provided to the acid gas treatment unit.