Fluid bed boiler for combusting biomass

Abstract

A biomass combustion fluidized bed boiler mainly comprises a fluidized bed boiler body. The boiler is characterized in that an independent hearth (3) at the high-temperature area is arranged, and communicates with an annular passage (11) between a round or nearly round polygonal internal cylinder (7) and a round or nearly round polygonal external cylinder (8), which are formed by a hearth transition area (4) and a membrane water cooling wall. A central flue (12) is arranged inside the internal cylinder (7), and a multi-stage secondary air nozzle (6) is arranged in the annular passage (11). As the independent hearth (3) at the high-temperature area is arranged, the invention settles the problem that a traditional boiler cannot hold a fuel layer and can combust the biomass granule fuel independently. The nearly-round polygonal structure of the annular passage (11) between the internal cylinder (7) and the external cylinder (8) is favorable for rotatory ascending of the flue gas. Moreover, the internal and external double heat exchange promotes the thermal efficiency of the boiler. The flue gas is segregated at a plurality of places, which promotes the environmental protection. The annular passage together with the secondary air replaces a high-temperature segregator and a medium-temperature segregator of a traditional boiler. The manufacture process is simple and the failure rate is greatly reduced.

Description

technical field [0001] The invention relates to a device capable of utilizing renewable biomass fuel, in particular to a fluidized bed boiler burning biomass fuel. Background technique [0002] At present, there are two major types of large-scale biomass fuel boilers with a capacity of more than 10t / h in the world: one is the technology of the Danish BWE Company, which uses water-cooled vibrating grate to incinerate biomass fuel. Unprocessed biomass fuel is used, which is unsafe and uneconomical for storage and transportation; the second is the use of circulating fluidized bed represented by Sweden and Germany, and several domestic enterprises have applied this technology, such as Beijing Tsinghua Unisplendour Environmental Protection Co., Ltd. The biomass-burning circulating fluidized bed boiler produced by the company in cooperation with a German company has a complex structure and needs to add fuel of different specific gravity, which will affect the environmental protect...

AI Technical Summary

Problems solved by technology

[0005] This invention applies the technology of vortex combustion to the biomass fuel boiler, and sets the furnace 3 in the high temperature zone separately, which changes the structure of the vortex combustion circulating fluidized bed boiler currently produced in China, which uses the lower part of the annular channel as the furnace in the high temperature zone, and solves the problem. It solves the problem that the boiler cannot maintain the fuel layer when burning biomass fuel; thus realizing the use of biomass fuel alone

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