COAL-FIRED GAS-TURBINE AND ASH SEPARATION SYSTEM

Application of a coal-fired gas turbine for combined-cycle power gener ation is discussed. A cycle with staged coal treatment, a counterflow combustor and an aerodynamic ash separation cyclone is chosen and its principal components are investigated. Conditions for self-stabilizing char (solid product of coal gasification) combustion are found experi mentally and by numerical simulation. It is shown that the obstacle of sticking ash can be obviated by staged combustion of the char and pro ducts of mild coal gasification. Experiments carried out with a coal-f ired gas turbine at the Technion Combustion Laboratory are described. The main component making it feasible and reliable is an ash separatio n device, whose performance is analysed experimentally and computation ally. Results indicate that the device suffices for the creation of a dynamically stable protective layer on the turbine blades. Efficiency studies indicate good performance of a metal multicyclone with swirl m otion of the aerosol initiated by air jets. Simulation of the two-phas e flow within the device, explaining its performance, is discussed. Co pyright (C) 1996 Elsevier Science Ltd.