| 摘要 |
PURPOSE:To largely increase the combustion efficiency of fed fuel, by eliminating all or almost all contacted heat transfer surfaces from a fluidized-bed combustion boiler, and by constituting all or almost all freeboard side walls, an exhaust gas duct, and a multi-cyclone connected to the gas duct, of heat-insulating structure. CONSTITUTION:When a fluidized-bed combustion is started by operating a fluidized-bed combustion boiler 1, particles from a fluidized-bed 2 scatter into a furnace built of freeboards 3. The temperature in the particles will not fall down, because the side walls made of freeboards 3 are in furnace structure 13. Part of particles fed into the furnace 13 is burned by the freeboards 3. The remaining particles get into the primary multi-cyclone 6 passing through an exhaust gas duct 5, together with exhaust gas. Particles of comparatively large sizes only are caught by the cyclone 6. The caught particles, kept in high temperature of 800-900 deg.C, are returned to the lower end of a freeboard 3 from the primary multi-cyclone 6 under the weight of their own only, passing through a circulation path 12', and are burned again at the freeboards 3. This process is repeated successively. As a result, the combustion efficiency of fuel being fed into the fluidized-bed combustion boiler can largely be increased. |
