A system for preventing the heating surface of the boiler from being contaminated by a double-fluidized bed combustion furnace

Abstract

The invention relates to a boiler heating surface contamination preventing system of a double-fluidized-bed combustion furnace. The system comprises a fluidized-bed combustion furnace and a fluidized-bed pyrolyzing furnace, the temperature of coal ash generated by burning in the fluidized-bed combustion furnace is high, the high temperature coal ash is collected through a cyclone separator, enters into the fluidized-bed pyrolyzing furnace through a coal ash distributor and is uniformly mixed with fed raw coal pulverized coal, the pulverized coal is pyrolyzed in the fluidized-bed pyrolyzing furnace by the heat of the coal ash and smoke of the fluidized-bed combustion furnace, alkali metals in the pulverized coal are volatilized and enter into a pyrolysis gas at the high temperature, the pyrolysis gas enters into a purifying device through a pyrolysis separator at the top of the fluidized-bed pyrolyzing furnace, the alkali metals are removed by purification, and the pysrolysis gas is fed into a furnace to burn; cokes and coal ash mixtures at an outlet of the fluidized-bed pyrolyzing furnace pass through a return feeder to server as coal as fired to be fed into the fluidized-bed combustion furnace for burning; and the alkali metals in the cokes are greatly reduced, an initial layer of contamination caused by the fact that alkali metal compounds in the smoke are cooled to adhere to the convection heating surface pipe wall is prevented, and the initial condition of forming the contamination is damaged.

Description

technical field

[0001] The invention relates to related technologies for reducing contamination on the heating surface of a boiler, and more specifically relates to a system for preventing contamination on the heating surface of a boiler in a double-fluidized bed combustion furnace. Background technique

[0002] my country's power generation industry is dominated by thermal power generation, with thermal power installed capacity exceeding 70%. Most of the coal used for thermal power is low-quality and low-grade coal. When high-alkaline coal is used, the alkaline compounds in the coal will volatilize during the combustion process and easily condense on the heating surface of the boiler to form sintering or bonding. The ash deposition of the heating surface causes corrosion, slagging and contamination of the equipment on the heating surface. Slagging and contamination will reduce the heat transfer efficiency of the boiler, affect the output of the boiler, and seriously reduce...

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