某200MW燃煤机组SCR烟气脱硝系统性能研究

Study on a Selective Catalytic Reduction System for NO_x Removal in a 200 MW Coal-fired Power Plant

在200 MW燃煤机组锅炉尾部烟道,建立了SCR脱硝系统性能测试平台,研究了入口烟温、NH_3/NO_x摩尔比和空间速度对脱硝效率和氨逃逸的影响;同时研究了烟气流量对脱硝系统阻力的影响。结果表明:入口烟温在340~370℃范围内,NH_3/NO_x摩尔比为1.0时,系统脱硝效率可达到80%以上。当NH_3/NO_x摩尔比小于1.08时,脱硝效率随NH_3/NO_x摩尔比增大而显著提高;当NH_3/NO_x摩尔比大于1.08时,脱硝效率提升不是很明显,而氨逃逸量会随NH_3/NO_x摩尔比的增大而一直增加,直至超出氨逃逸的设计限值。在入口烟温为360℃、NH_3/NO_x摩尔比为1.08时,调节反应器入口烟气流量,使空间速度在3300~4000 h^(-1)时,脱硝效率最佳,此时氨逃逸量低于2ppm。随着烟气流量的增大,脱硝系统的流动阻力和催化剂层的流动阻力逐渐增大,并且催化剂层阻力占脱硝系统阻力的75%左右。

In a 200MW coal-fired power plant, a SCR denitrification system performance test platform was built at the boiler back pass. The influence of inlet flue gas temperature, NH3/NOx molar ratio and space velocity on its denitrification efficiency and ammonia slip were studied. The influence of flue gas flow on the resistance of SCR denitrification system was also performed. Results showed that when the inlet flue gas temperature lay in 340-370℃, and the NH3/NOx molar ratio was 1.0, the denitrification efficiency could reach more than 80%. When the molar ratio of NH3/NOx was less than 1.08, the denitrification efficiency would significantly increase with the growing molar ratio of NH3/NOx. When the molar ratio of NH3/NOx was more than 1.08, the increase of the denitrification efficiency was not very obvious, but the quantity of ammonia slip increased with the growing molar ratio of NH3/NOx until it was beyond the limit of designed requirement. When the inlet flue gas temperature was 360 ℃, and NH3/NOx molar ratio was 1.08, adjust the inlet flue gas flow of the reactor to control the space velocity in the range of 3300-4000h-1, at this time the denitrification efficiency was high, and the quantity of ammonia slip was less than 2 ppm. With the increase of flue gas flow, the flow resistance of denitrification system and catalyst layers also increased gradually, and resistance of catalyst layers accounted for about 75% of the whole resistance of denitrification system.