Development of a pressurized combustion system for fluidized bed coal

The employment of combined gas and steam turbine processes for the production of electrical power offers potentially much higher efficiency than conventional steam power processes. The use of domestic brown coal however requires a suitable pressurised combustion system which is capable of delivering a sufficiently clean hot gas to the gas turbine inlet. In addition to processes based on a prior gasification of the solid fuel, development of direct combustion processes is now concentrating on two major directions: Pressurised fluidised-bed furnaces and pressurised PF firing systems. For smaller combined-cycle plants a new firing system variant is now available, the cycloid firing system which had already been developed for waste incineration and the heat production market. This type of furnace is operated as a dry cyclone with temperatures below the ash softening point. For relatively low plant investment costs, a high burnout and low gaseous pollutant emissions can be achieved. Further development work on pressurised firing systems is being carried out at the Energie Ressourcen Institut Cottbus e.V. Here a pressurised cycloid furnace with a fuel output of approx. 200 kW has been set up on a laboratory scale. The experimental rig has received funding from the European Union and the Land Brandenburg. The research project is financed by the Federal Ministry for Education and Research (BMBF) and the industrial partners Lausitzer Braunkohle AG and BBP Environment GmbH (formerly Steinmuller Gummersbach GmbH).