A gas turbine cogeneration system using a coal fired atmospheric fluid bed (AFB) combustor represents an environmentally clean and less costly alternative to the oil or gas fired electric power generators, process steam boilers and process heaters that are necessary for the operations of both small and large industrial energy users.
This paper describes a cogeneration system which uses an air-to-gas heat exchanger tube assembly immersed in an AFB combustor to indirectly heat the compressor airflow from a gas turbine. This AFB combustor replaces the conventional direct fired oil or gas combustor. The flue gas from the AFB is used to produce steam and the waste energy from the gas turbine exhaust is used to provide additional steam or clean hot process air. By appropriate selection of components, AFB cogeneration systems can provide electrical-to-thermal ratios of 30 to 150 kilowatts per 1000 pounds of steam for a range of applications.
The paper presents the key design features of this type of system. The selection of materials and mechanical configurations are presented. The status of the technology and the R&D supporting test results are discussed. Cogeneration applications are discussed.