Method for reducing coal-firing boiler NOx discharge and its implementing device

Abstract

A method for reducing the NOx exhaust of a boiler, organizing multistage main coal powder burner to burn, and spraying hierarchical fuel to the flame center at the downstream of the main burner, the hierarchical fuel is decomposed quickly under high temperature and oxygen-deficient condition to generate great amount of CHi group, the CHi group then deoxidizes the NOx generated in the main burner area to N2, the selective non-catalytic deoxidize for NOx is proceeded by nitrogen group on a section with flame average temperature is 850-1150 DEG C, the fuel is then synergized by alkali metal salt, at last the fuel that not burnt is burnt by burning wind. A device for realizing the method which is disposed with a fuel classification nozzle, a reducing reagent nozzle and an air classification nozzle on a unidirectionalflow coal powder burner, the position of the fuel classification nozzle is at the section place of the flame center; the reducing reagent nozzle is at the place with an average temperature is 850-1150 DEG C of the section; the air classification nozzle is determined by the hierarchical fuel detention period 0.5-1 S.

Description

technical field [0001] The invention belongs to the field of thermal energy engineering, and relates to coal-fired power station boilers and coal-fired industrial boilers. Background technique [0002] Traditional DC pulverized coal burner: The traditional DC pulverized coal burner is shown in Figure 1. It consists of multi-stage pulverized coal burners 2. Three nozzles such as secondary air spout 103 are formed. [0003] Existing technologies for reducing NOx emissions from coal-fired boilers include: [0004] 1. Air classification technology: It is based on the traditional pulverized coal burner and reduces NOx by delaying the mixing of air and fuel, such as overall furnace air classification (OFA), coaxial combustion (CFS, TFS2000), rich and thin combustion and low Oxygen combustion and other technologies. Air classification technology can reduce NOx emissions by 20% to 30%. A typical combustion device using air staging technology is an OFA low NOx burner, as shown in...

AI Technical Summary

Problems solved by technology

When the working temperature of SNCR method is lower than 900℃, NH 3 The reduction reaction of NH is not complete, which will cause the so-called "ammonia breakthrough", and when the working temperature is higher than 1100 °C, NH 3 The amount of oxidation to NO increases, resulting in an increase in the concentration of NOx emissions

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