Abstract: A novel combustion device is installed into a gas turbine to permit operation with solid or other high ash fuels. A refractory burner block defines an annular primary combustion chamber and a number of secondary cyclonic combustion chambers positioned radially inwardly of the primary chamber. Waste wood or other solid fuels are charged into the primary combustion chamber. Pressurized combustion air flows derived from the turbine's compressor are introduced tangentially into the primary chamber thereby creating a vortex. A number of passages place the primary chamber in communication with the secondary chambers. These passages are formed in a radially inner wall of the primary chamber so that fuel particles are retained within the primary chamber by centrifugal forces until reduced to an appropriate size for combustion in the secondary chambers.