Patent ID: 6862877

Claim:
A biomass fuel combustor for use in the pressurized combustion of biomass fuel particles to produce a pressurized exhaust gas for use in a direct cycle biomass-fired gas turbine system, the combustor comprising: a cyclonic combustion chamber having an upstream combustion region and a downstream combustion region, the downstream region being arranged to receive combustion products from the upstream region, the upstream region having first and second fuel inlets, the second inlet allowing the entry into the upstream region of biomass fuel particles for combustion and the first inlet allowing the entry into the upstream region of fluid secondary fuel for combustion in the upstream region at least during start-up of the combustor; wherein heat is supplied to the upstream region, thereby promoting fragmentation in the upstream region of the biomass fuel particles entering the upstream region via the second inlet, wherein the second inlet is positioned such that biomass fuel particles enter the upstream region via the second inlet with a tangential component to promote cyclonic motion of gases and biomass particles in the upstream region and wherein the downstream region of the combustion chamber is provided with a plurality of air injection openings arranged such that air enters the downstream region of the combustion chamber with a tangential component to promote cyclonic motion of gases and fragmented biomass particles in the downstream region of the combustion chamber, wherein the combustor further comprises a first outlet for the efflux from the combustion chamber of the hot pressurized combustion gas resulting from the biomass and/or secondary fuel combustion and also further comprises a dilution chamber downstream of said first outlet, said dilution chamber being provided with one or more third inlets for the supply to the dilution chamber of air to dilute the hot pressurized combustion gas.