Patent ID: 7614352

Claim:
A process for capturing and recovering carbon dioxide and sulphur dioxide from the combustion of a carbonaceous fuel having a high carbon content, a relatively high sulphur content and a low ash content, which process comprises: (a) splitting a flow of carbonaceous fuel having a particle size compatible with combustion in a fluidized bed into a major proportion and a minor proportion; (b) transferring the major proportion of the fuel to a pressurized fluidized bed combustor and carbonator, PFBC/C; (c) combusting the major proportion of the fuel flow in the PFBC/C in the presence of air and in the presence of calcium oxide; (d) recovering a flue gas flow containing solids including calcium carbonate and calcium sulphate from the PFBC/C; (e) separating the solids from the flue gas flow; (f) transferring the minor proportion of the fuel to a calciner; (g) combusting the minor proportion of the flow of fuel in the calciner in the presence of both relatively pure oxygen and the solids flow separated in step (e) to convert the calcium carbonate in the solids flow into calcium oxide and carbon dioxide gas; (h) discharging a flow of carbon dioxide gas substantially free of contamination (i) recovering said flow of carbon dioxide gas substantially free of contamination; (j) recovering a flow of solids from the calciner including the calcium oxide generated in the calciner; (k) transferring the flow of solids obtained in step (j) to the PFBC/C to provide the calcium oxide required in step (c); and (l) recovering calcium sulphate and spent solids from the solids flowing through the PFBC/C and adding fresh calcium carbonate to the calciner to maintain a solids balance within the process.