Reburning type circulating fluidized bed boiler

Abstract

The invention discloses a reburning type circulating fluidized bed boiler, and belongs to the technical field of coal combustion technology and equipment. In the reburning type circulating fluidized bed boiler, a reburning bed is arranged on the pipeline of a material returning pipe to a hearth; the reburning bed is arranged on the pipeline between a material returning device and the hearth; and the reburning bed is a burning area enclosed by fireproof materials at the periphery. When the reburning type circulating fluidized bed boiler runs, air is blasted into the reburning bed, so that fly ash is burnt in the reburning bed and the fly ash after being burnt enters a dense-phase area of the hearth to bring the heat back to the hearth with the fly ash. In the process, the temperature of the reburning bed can be controlled according to the size of the ventilating capacity. The reburning type circulating fluidized bed boiler has the advantages that: the structure is simpler, the effective residence time of the fly ash is prolonged, the carbon content of the fly ash is reduced, and the sufficiency of combustion is improved. In addition, the excess air coefficient of the hearth can be indirectly controlled by adjusting the ventilating capacity of the reburning type circulating fluidized bed boiler.

Description

technical field [0001] The invention relates to a circulating fluidized bed boiler (CFB boiler), in particular to a circulating fluidized bed boiler with a reburning device, which belongs to the technical field of coal combustion technology and equipment. Background technique [0002] Circulating fluidized bed boiler (CFB) technology is a new type of clean combustion technology. The operating temperature of the circulating fluidized bed is usually lower than that of the pulverized coal furnace, so the burnout time of the coal particles is relatively long, which leads to the high carbon content of the fly ash of the circulating fluidized bed boiler, which in turn affects the efficiency of the boiler. There are some solutions to this situation. One is that the fly ash particles are returned to the upper part of the dilute-phase area or the dense-phase area in the furnace for back-burning; the other method is that the fly-ash particles are returned to the bottom of the dense-p...

AI Technical Summary

Problems solved by technology

[0004] The purpose of the present invention is to provide a reburning circulating fluidized bed boiler for existing CFB boilers with high carbon content in fly ash, complex structure of external heat exchange bed and high cost of heat exchange equipment. , aiming to use a relatively simple structure and make full use of the space outside the furnace to further improve combustion efficiency, reduce the carbon content of fly ash, and better control the excess air coefficient in the furnace

Images