Process for producing CO2, and CO2 so produced

Claim 1

A process for making CO 2 comprising the steps of: (a) passing a carbon-containing fuel to a dense-phase fluidized fuel-conversion bed containing particles comprising reactive CaSO 4 and particles comprising reactive CaO, the bed being fluidized by passing into the bottom thereof a fluidizing gas which is substantially free of nitrogen and which contains an oxygen transfer agent and/or a source thereof for mediating the transfer of oxygen from CaSO 4 to fuel whereby the fuel is partially oxidized to products including CO and CO 2 , and some CaSO 4 is reduced to CaS substantially without the liberation of sulfur moieties, the temperature of the fuel conversion bed being such that CaO will react with CO 2 to form CaCO 3 within the fuel conversion bed; (b) causing particles including particles comprising CaSO 4 , particles comprising CaS and particles comprising CaCO 3 to pass to a fluidized decarbonation bed which is fluidized by passing into the bottom thereof at least some of the partially oxidized gas products obtained from the fuel conversion bed, said gas products constituting the sole fluidizing medium for the fluidized decarbonation bed and which gas products include hydrogen and/or a source thereof for transferring oxygen from CaSO 4 to CO to thereby oxidize CO to CO 2 and to reduce CaSO 4 to CaS, the decarbonation bed being operated at a temperature above the decarbonation temperature of CaCO 3 whereby CaCO 3 is decomposed to CaO and CO 2 thereby increasing the amount of CO 2 in the gas passing through the decarbonation bed; (c) recovering a gas containing CO 2 from the top of the decarbonation bed; (d) passing particles containing reactive CaS from the fluidized decarbonation bed to a fluidized oxidation bed in which the particles are fluidized by passing into the bottom of the bed a gas containing molecular oxygen whereby at least some reactive CaS is oxidized to reactive CaSO 4 with the liberation of heat which maintains the temperature of the oxidation bed above that of the fuel-conversion bed; and, (e) passing particles containing reactive CaSO 4 from the oxidation bed to the decarbonation bed and/or to the fuel-conversion bed.