Gasification of ash-containing solid fuels

A method of converting an ash-containing solid or semi-solid fuel to a combustible gas comprising establishing a single fluidized fuel conversion bed having a bottom zone operating at fuel conversion conditions including a temperature below ash-softening temperatures, and an upper zone operating at fuel conversion conditions including ash-softening temperatures, feeding all of the fuel directly into the bottom zone whereby at least some of the fuel is converted in the bottom zone to combustible gas and vapor-phase precursors thereof, and whereby unconverted solid particles of fuel material of reduced size and/or weight together with at least some associated ash are upwardly entrained into the upper zone wherein at least some of the unconverted solid fuel material from the bottom zone is converted to combustible gas so that a reduced quantity of fuel material is elutriated from the bed and wherein at least some of the ash softens and agglomerates and/or sticks to solids in the upper bed zone so that a reduced quantity of ash is elutriated out of the conversion bed and so that bed solids comprising agglomerated and/or adhered ash sink from the upper zone of the bed to a bottom region of the bottom zone of the bed from where they can be withdrawn.