煤粉锅炉气体再燃及SNCR联合 脱硝的实验研究

对某厂一台240 t/h煤粉锅炉采用空气分级、化工合成气再燃及以氨气为还原剂的SNCR(选择性非催化还原)等技术进行联合脱硝改造。实验结果表明:气体再燃比在0~20%时,随着再燃量增大脱硝效率增加,高、低负荷工况时脱硝效率可达39.1%、43.1%;SNCR喷射点位置沿炉膛纵深存在温度梯度,水冷壁附近温度梯度较大,靠近炉膛中心处温度梯度降低;在空气分级基础上,高、低负荷工况时SNCR可分别提高35.1%、42.4%脱硝效率,氨气的使用不会造成锅炉效率的降低;满负荷工况采用气体再燃及SNCR技术联合脱硝时,在尾部氨逃逸小于12 mg/m3时,可达到80.2%的整体脱硝效率。

The experimental study on joint denitration by Gas Reburning and SNCR In PC-boiler

Taking an 240 t/h pulverized coal fired boiler that was De-NOx transformed using air-staged, chemical syngas as re-burning fuel and gas-state ammonia as the reductant of SNCR joint de-nitration technology as object, this paper tested the de-nitration effect after reforming. Results showed that as the gas amount ranged from 0 to 20%, the de-nitration efficiency increased with the increasing of re-burning fuel, the de-nitration efficiency under high and low load conditions can reached 39.1% and 43.1% respectively; Along the depth of the furnace, the temperature for SNCR injection point had gradient, temperature gradient was larger near the water wall and it declined near the center of the furnace; the SNCR de-nitration efficiency can reached 39.1% and 43.1% under high and low load condition based on air-staged, respectively, what is more, the use of ammonia gas would not reduce the efficiency of the boiler; under full load condition, the de-nitration efficiency can reached 80.2% using gas re-burning combined with SNCR technology, while ammonia slip within 15 ppm.