Development of a gravel bed combustor for a solid fueled gas turbine for the period February 1, 1989 to June 30, 1991

Further work on a novel pressurized, downdraft combustor using aspen woodchips is reported for the period 2/89 to 6/91. The 42 cm i.d combustor was connected to a modified Allison 250-C20B gas turbine engine and operated for 250 hours. The performance of the combustor-turbine system is discussed. Deposits of ash on the turbine nozzles and rotors are identified and discussed. A dynamic simulation model for the combustor-turbine system is presented and used to investigate the control of the system. The highest net power output was 61 kW or 20% of full power; the highest turbine speed was 75% of the maximum speed; the highest mass flow was 50% of the full power flow. The stability of the combustor must be improved before higher output and longer runs can be achieved