Waste-Fueled Circulating Fluidized Bed Boiler

This boiler features an all-steel structure, fully membrane-type water-cooled walls, circulating fluidized bed combustion, and a high-temperature insulated shell-type cyclone separator for gas-solid separation. The water circulation system uses natural circulation, and the flue gas system employs balanced ventilation. The boiler is partially arranged outdoors, with a waste + bituminous coal fuel mixture, burning a small amount of waste leachate. The boiler consists of a membrane water-cooled wall furnace, an insulated cyclone separator, and a tail vertical shaft flue. The upper part of the vertical shaft flue is covered by a membrane-type wall superheater, and the lower part comprises a lined flue. The low-temperature superheater, high-temperature superheater, and evaporator bundles are arranged in the upper part of the vertical shaft, while the high-temperature economizer, high-temperature air preheater, low-temperature economizer, and low-temperature air preheater are arranged in the lower part. Between the membrane-type wall superheater and the low-temperature superheater, a primary water spray desuperheater is installed, and between the low-temperature and high-temperature superheaters, a secondary desuperheater is installed to control the rated steam temperature at the superheater outlet. The heat for steam generation is provided by the fluidized bed system. The high-temperature flue gas, carrying material, flows upward through the furnace, entering the shell-type insulated cyclone separator tangentially through outlets located on both sides of the rear water-cooled wall at the top of the furnace. The coarse material is separated in the cyclone separator and returned to the dense phase area above the air distribution plate in the furnace through the return feeder, achieving circulating combustion. The flue gas exits the boiler through the outlet flue at the top of the cyclone separator and flows through the membrane-type wall superheater's front wall sparse tubes into the tail vertical shaft flue. In the vertical shaft flue, the flue gas flows downward, transferring heat to the walls and the tail heating surfaces inside the shaft, and finally passes through the air preheater in the lower part of the vertical shaft flue before leaving the boiler body.