Abstract: A pyrolysis-combustion dual-bed system comprises a fluidized bed, a cyclone separator, a coal ash distributor, an ash-coal mixer, a lower pyrolysis bed, a return feeder and a cleaner, wherein the cyclone separator is connected with an upper lateral side of the fluidized bed, the outlet end of the cyclone separator is connected with the inlet end of the coal ash distributor; the two outlets of the lower pyrolysis bed are respectively connected with the inlet of an external bed and the inlet of the cleaner; the outlet of the external bed is connected with the inlet of the return feeder; the return feeder close to the lower lateral side of the fluidized bed is connected with the inlet on the lower lateral side of the fluidized bed; and the outlet of the cleaner is connected with the inlet of the lower lateral side of the fluidized bed.

Abstract: A dual-bed system for preventing a boiler heating surface from being contaminated comprises a fluidized bed, a cyclone separator, a coal ash distributor, an ash-coal mixer, a lower pyrolysis bed, a return feeder and a cleaner, wherein the cyclone separator is connected with the upper lateral side of the fluidized bed; the inlet end of the coal ash distributor; the two outlets of the coal ash distributor are respectively connected with the inlet of the return feeder and the inlet of the ash-coal mixer; the outlet of the ash-coal mixer is connected with the inlet of the lower pyrolysis bed; the return feeder close to the lower lateral side of the fluidized bed is connected with the inlet on the lower lateral side of the fluidized bed; and the outlet of the cleaner is connected with the inlet on the lower lateral side of the fluidized bed.

Abstract: An external bed type double-fluidized bed system for preventing boiler contamination includes a fluidized bed combustion furnace, a cyclone separator, a coal ash distributor and a fluidized bed pyrolysis furnace. The fluidized bed combustion furnace is connected with the coal ash distributor, the coal ash distributor is connected with the coal ash inlet on a side wall of the fluidized bed combustion furnace through a return feeder with which the coal ash outlet of the fluidized bed pyrolysis furnace is also connected through an external bed, and the return feeder is connected with the fluidized bed combustion furnace. A fuel coal is pyrolyzed in the fluidized bed pyrolysis furnace at a temperature to volatize alkali chlorides into a pyrolysis gas, thereby reducing the content of the alkali chlorides contained in the coal in the fluidized bed combustion furnace and relieving the contamination to a convective heat-absorbing surface.

Abstract: A pyrolysis-combustion dual-bed system Comprises a fluidized bed, a cyclone separator, a coal ash distributor, an ash-coal mixer, a lower pyrolysis bed, a return feeder and a cleaner, wherein the cyclone separator is connected with an upper lateral side of the fluidized bed, the outlet end of the cyclone separator is connected with the inlet end of the coal ash distributor; the two outlets of the lower pyrolysis bed are respectively connected with the inlet of an external bed and the inlet of the cleaner; the outlet of the external bed is connected with the inlet of the return feeder; the return feeder close to the lower lateral side of the fluidized bed is connected with the inlet on the lower lateral side of the fluidized bed; and the outlet of the cleaner is connected with the inlet of the lower lateral side of the fluidized bed.

Abstract: An external bed type double-fluidized bed system for preventing boiler contamination includes a fluidized bed combustion furnace, a cyclone separator, a coal ash distributor and a fluidized bed pyrolysis furnace. The fluidized bed combustion furnace is connected with the coal ash distributor, the coal ash distributor is connected with the coal ash inlet on a side wall of the fluidized bed combustion furnace through a return feeder with which the coal ash outlet of the fluidized bed pyrolysis furnace is also connected through an external bed, and the return feeder is connected with the fluidized bed combustion furnace. A fuel coal is pyrolyzed in the fluidized bed pyrolysis furnace at a temperature to volatize alkali chlorides into a pyrolysis gas, thereby reducing the content of the alkali chlorides contained in the coal in the fluidized bed combustion furnace and relieving the contamination to a convective heat-absorbing surface.

Abstract: A dual-bed system for preventing a boiler heating surface from being contaminated comprises a fluidized bed, a cyclone separator, a coal ash distributor, an ash-coal mixer, a lower pyrolysis bed, a return feeder and a cleaner, wherein the cyclone separator is connected with the upper lateral side of the fluidized bed; the inlet end of the coal ash distributor; the two outlets of the coal ash distributor are respectively connected with the inlet of the return feeder and the inlet of the ash-coal mixer; the outlet of the ash-coal mixer is connected with the inlet of the lower pyrolysis bed; the return feeder close to the lower lateral side of the fluidized bed is connected with the inlet on the lower lateral side of the fluidized bed; and the outlet of the cleaner is connected with the inlet on the lower lateral side of the fluidized bed.