Biomass boiler equipped with external fluidized bed

Abstract

The invention provides a biomass boiler equipped with an external fluidized bed. The biomass boiler comprises a hearth, an air distribution plate, two separators, the external fluidized bed and a tailflue; the bottom of the hearth is provided with the air distribution plate; the two separators are arranged on the rear side of the top of the hearth; the tops of the separators are connected to thetail flue; blanking pipes at the lower ends of the separators are connected to the upper end of the external fluidized bed; an ash return port in the side wall at the lower part of the hearth is connected with the side wall at the lower end of the external fluidized bed; the external fluidized bed is provided with the hearth 1, the hearth 2 and the hearth 3 side by side along the width of the hearth; a first-level high-temperature superheater, a reheater and a second-level high-temperature superheater are separately arranged in the hearth 1, the hearth 2 and the hearth 3. The biomass boiler fundamentally avoids the problem of high temperature corrosion of the superheater and reheater of the existing biomass fluidized bed boiler. Because the external fluidized bed has the function of adjusting the furnace temperature, the biomass boiler can adapt to large changes in load and fuel, and meanwhile, ensures lower pollutant emissions.

Description

technical field [0001] The invention belongs to the technical field of fluidized bed boilers, in particular to a biomass boiler equipped with an external fluidized bed. Background technique [0002] Biomass direct-fired fluidized bed boiler is a high-temperature, ultra-high pressure, once-reheat boiler. The fuel of biomass boilers varies greatly. Corn straw, wheat straw, forestry waste, building formwork, etc. are the main fuels. The composition, water content, and calorific value of various fuels vary greatly. The moisture content of the biomass fuel also changes greatly; the high content of Cl, K, and Na in the biomass fuel will form ash on the surface of the high-temperature superheater and high-temperature reheater tubes, and high-temperature corrosion will occur. This is the cause of high-parameter fluidized bed boilers. One of the main reasons for shutting down the furnace for maintenance. [0003] The existing biomass fluidized bed boilers mainly include the followi...

AI Technical Summary

Problems solved by technology

Superheater and reheater are susceptible to high temperature corrosion

(3) With the structure of a coal-fired boiler, water cooling and superheating screens are arranged in the upper part of the furnace, and the high and low temperature superheaters are arranged in the upper part of the tail flue. The fuel adaptability is poor, and the tail heating surface is prone to dust accumulation and corrosion.

For the above furnace types, when the fuel and boiler load change, the furnace temperature is difficult to control, and the boiler load adaptability is poor

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