Method of converting liquid and/or solid fuel to a substantially inerts-free gas

A method of converting liquid hydrocarbon fuel and/or solid carbonaceous fuel to a substantially inerts-free reducing and/or synthesis gas product, said method comprising:

• (a) passing the fuel into a fuel conversion zone comprising a conversion bed of solid particles which are maintained at an elevated fuel conversion temperature and fluidized by a fluidizing gas which is paased into the bottom of the conversion bed, the conversion bed containing solid particles comprising calcium sulfate which constitutes substantially the sole source of oxygen used in the conversion of the fuel, the fluidizing gas comprising at least one gas phase and/or vapour phase substance which serves to promote and/or mediate the transfer of oxygen to the fuel and/or to partially converted fuel derivatives from the calcium sulfate, which is thereby reduced to calcium sulfide whereby a substantially inerts-free reducing and/or synthesis product gas leaves the top level of the conversion bed, the fluidizing gas being substantially free of molecular oxygen and unreactive and/or inert materials which would dilute the gas product;
• (b) transferring solid particles containing calcium sulfide from the fuel conversion zone to an oxidizer bed in an oxidation zone and passing into the bottom of the oxidizer bed a gas containing molecular oxygen at a rate sufficient to fluidize the solid particles in the oxidation bed and to oxidize the calcium sulfide in said solid particles to form said calcium sulfate with the generation of heat which maintains the temperature of particles in the oxidizer bed higher than the temperature of particles in the conversion bed;
• and
• (c) transferring the solid particles comprising said calcium sulfate from the oxidizer bed to the conversion bed for use in converting further quantities of fuel in the conversion bed, the solid particles thus transferred to the conversion bed furnishing at least some heat for maintaining the conversion bed at the said elevation fuel conversion temperature.