Thermal carbon composite denitration method for coal-fired boiler

Abstract

The invention discloses a thermal carbon composite denitration method for a coal-fired boiler, and relates to a denitrifying agent and a preparation method and a use method thereof. The method comprises the following steps: mixing 80 to 100 mass percent of powdered coke, 0 to 20 mass percent of calcium material and 0 to 5 mass percent of vanadium slag; grinding the mixture until the fineness is 75 mu m and the sieve residue is less than 10 percent; and taking flue gas extracted from a tail flue of the boiler as a conveying medium, spraying the denitrifying agent of which the combustion heat output is 10 to 20 percent of the fuel heat output into a hearth in a multi-point opposite spraying mode through a spray head which is arranged in a region at the temperature of between 950 and 1,200 DEG C on the upper part of the hearth of the coal-fired boiler, and maintaining the excess air factor alpha be less than 1. The method realizes denitration in the boiler, has the denitration efficiency of more than 80 percent, less investment cost, low operation cost and good safety in the operation process.

Description

technical field [0001] The invention relates to a thermal carbon compound denitrification method for a coal-fired boiler, which belongs to the technical field of environmental protection. Background technique [0002] Coal-fired energy accounts for 85% of my country's energy structure, and thermal power accounts for 80% of the power structure. The rapid development of thermal power has produced a large amount of gas pollutants, nitrogen oxides being one of them. [0003] Coal-fired boiler nitrogen oxide control technology can be generally divided into two categories, namely denitrification during combustion and denitrification after combustion. The denitrification technologies in combustion mainly include: 1) low-temperature combustion; 2) low-oxygen combustion; 3) low NO x Burner; 4) flue gas recirculation technology, etc. [0004] Post-combustion denitrification technologies mainly include: 1) Non-catalytic reduction technology: spray ammonia or urea on the upper part o...

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Problems solved by technology

[0005] The denitrification technology in combustion has the characteristics of simple system, relatively low cost of transformation and operation, but the disadvantage is that the denitrification efficiency is low, and it cannot meet the requirements of deep reduction of NOx emissions

The denitrification efficiency of post-combustion denitrification technology is relatively high, even exceeding 90%, but its system is complicated, and the construction and operation costs are high, so it is very difficult to promote it in a large area in my country

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