... boiler):Single steam drumNatural circulationCirculation fluidized bed combustionOpen-air type arrangementThe boiler consists a membrane walled combustion chamber, ... combustion chamber, panel type heating surface, 9 pieces of membrane type super-heater, 6 pieces of membrane type re-heater and ... into one flue, in which screw shape extended surface tube type of coal economizer is provided.Air pre-heater ...