Biomass gasified gas re-burning mode and system for coal-fired fluidized bed

Abstract

The invention belongs to the technical field of N2O emission reduction in a coal-fired fluidized bed, and particularly relates to a biomass gasified gas re-burning mode and a biomass gasified gas re-burning system for a coal-fired fluidized bed. The wall of a fluidized bed boiler is provided with a plurality of biomass gasified gas nozzles, biomass gasified gas is introduced into a hearth of the fluidized bed boiler, and the biomass gasified gas is reacted with N2O-containing smoke generated by burning of coal dust in the hearth to realize multi-stage re-burning so as to improve the burning efficiency of the whole fluidized bed and reduce the emission of N2O. Compared with pyrolysis and direct burning, the biomass gas rich in combustible substances such as H2, CH4, CO and the like has low ash content and extremely low sulfur content, has no sulfur removal problem, is ideal re-burning fuel and can effectively reduce the emission of nitrogen oxides by using mixed burning of the biomass gasified gas and the coal dust; and because of low alkali metal and chlorine content in the gasified gas, problems of slag formation and corrosion can be avoided, utilization of the coal dust is not affected and efficient clean utilization of the biomass can be realized.

Description

technical field [0001] The invention belongs to coal-burning fluidized bed reducing N 2 In the field of O emission technology, it particularly relates to a reburning method and system of biomass gasification gas in a coal-fired fluidized bed, which can be used for mixed combustion of pulverized coal and biomass gasification gas to reduce N 2 O emissions. Background technique [0002] Circulating fluidized bed power generation technology has developed rapidly in my country in recent years. Many 300MW circulating fluidized bed (CFB) power stations have been put into operation. Compared with conventional pulverized coal boilers, circulating fluidized bed boilers NO x and SO x The emission concentration is low, but another pollutant N 2 The emission concentration of O is generally 39~589mg / Nm 3 , sometimes even up to 786mg / Nm 3 , much higher than the traditional pulverized coal furnace N 2 O emission is less than 20mg / Nm 3 s level. N 2 O, commonly known as laughing gas,...

AI Technical Summary

Problems solved by technology

[0008] 5. Introduce combustible gas (such as methane) to increase the flue gas temperature to reduce N 2 O, is a simple and easy method, but requires a dedicated gas pipeline, and its application is affected by the gas grade and economic constraints

This device also directly uses biomass to reburn, and there are also problems such as blockage, coking and corrosion.

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