Circulating fluidized bed boiler applied to high sodium coal and biomass fuel

The utility model discloses a circulating fluidized bed boiler applied to high sodium coal and biomass fuel. The circulating fluidized bed boiler comprises a water-cooling wind box, a feeding port, a hearth, a screen-type heat exchanging surface, a cyclone separator and a vertical hollow flue, wherein the water-cooling wind box is surrounded by membrane walls; the hearth is surrounded by membrane walls; the screen-type heat exchanging surface comprises a film-type wall; the vertical hollow flue is communicated with the upper part of the cyclone separator; the heating surface of the hollow flue comprises a steam-cooling packing wall; a horizontal flue is arranged at the downstream part of the hollow flue; and a low-temperature convection heating surface, a coal economizer heating surface and an air preheating device heating surface are arranged in the horizontal flue in sequence. According to the circulating fluidized bed boiler, the problem that high sodium coal stains and is bonded to the convection heating