Low-low-nitrogen combustor for large and medium-sized pulverized coal boilers under wide-load operation, and using method

Abstract

The invention discloses a low-low-nitrogen combustor for large and medium-sized pulverized coal boilers under a wide load condition, and a using method. A primary air system which can meet the requirement that the interior of the cross section of a hearth at the position is always a high-concentration pulverized coal area and is stable in combustion and free of coking under any load / coal type working condition is arranged in the middle of a hearth combustor in the vertical direction; an afterburning air system which can be used for spraying air into the internal space of the cross section of the hearth is arranged at the upper part of the hearth combustor; during operation under a low-load working condition, a middle hearth space can remain enough pulverized coal concentration, and forms an anoxic high-temperature combustion area, and a large amount of carbon monoxide is generated to fully inhibit generation of thermal nitric oxide; and in the upper afterburning air area, an upper hearth forms an oxygen-enriched relatively-low-temperature combustion area through regulation and control of the afterburning air volume, and the temperature is lower than the temperature generated by thethermal nitric oxide, so that high-concentration carbon monoxide is fully combusted. The method has remarkable energy-saving and environment-friendly benefits during low-load operation of the large and medium-sized boilers.

Description

technical field [0001] The invention belongs to the field of engineering thermophysics, and in particular relates to a low-low-nitrogen burner and a use method of a large and medium-sized pulverized coal boiler under wide-load operation. Background technique [0002] With the adjustment and gradual advancement of my country's energy structure, the electric energy produced by new energy technologies such as wind energy and solar energy has gradually increased, the peak-shaving range of boilers in large-scale thermal power plants has increased, and low-load long-term operation has become the norm. In order to meet the electricity demand during the peak period or when new energy is insufficient, the boilers of large and medium-sized thermal power plants must be large enough to meet the peak-shaving range of 25%-100%, and the rated evaporation range is 670 t / h (corresponding to the rated power generation capacity of 600 MW) ~ 3000 t / h to meet the power generation conditions of h...

AI Technical Summary

Problems solved by technology

Due to the large size of the furnace, low-load economical operation often encounters unstable combustion in the furnace, excessive oxygen content in the pulverized coal furnace, and a significant increase in the generation of nitrogen oxides. additional questions

During low-load and low-oxygen operation, the concentration of carbon monoxide generated in the furnace is generally too high, the concentration of carbon monoxide in the exhaust flue gas is too high, and the utilization rate of coal-fired energy decreases

At the same time, insufficient coal combustion will cause the furnace temperature to fall below the standard, the main steam temperature of the superheater will be too low, and the heat-to-electricity conversion efficiency of the steam turbine will also decrease accordingly.

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