基于空气分级的主燃区喷氨技术降低锅炉NO_x的热态工业试验研究

Experimental study on reagent injection in primary combustion zone for NO_x control based on the air classification

基于空气分级主燃区喷氨技术降低NO_x,在一台240 t/h煤粉炉上进行了热态工业试验,并对主燃区的喷氨位置、化学氨氮比(NSR)、OFA运行方式、锅炉负荷等因素对NO_x还原效果的影响进行了试验研究。结果表明:锅炉中下磨满负荷运行时,主燃区四角的喷氨降低NO_x的效果优于侧墙,并且随着化学氨氮比的增加而增加,在NSR=1.6时取得35%的脱硝效率,当OFA的阀门开度维持在60%以下,锅炉运行时的脱硝效果较好,降低锅炉的负荷,相应地提高了主燃区喷氨的脱硝率,中上磨运行时,主燃区喷氨脱硝效果不佳,空气分级结合主燃区喷氨技术可以取得75%的脱硝率。

It aimed to demonstrate a thermal state industrial test in a 240 t/h pulverized coal furnace that based on air staging by spraying ammonia technology in the main combustion zone to reduce NOx. Also, the factors of NO reduction effect were studied, such as, the place which ammonia was sprayed in the main combustion zone, chemical ammonia nitrogen ratio （NSR） , OFA operation, boiler load and so on. Results showed that ： when the coal mills that were in the middle and underneath floors were in the full load, the denitration effeeiency of injecting NH3 into the primary com- bustion zone from the corners of furnace was superior to that from the side walls. And in increased as the increasing of the NSR, when the NSR was up to 1.6, denitration efficiency could reach 35%. When the valve opening degree of OFA maintained under 60% , the denitration effect was better, which could decrease the load of the boiler, and im- prove spraying ammonia denitration rate in the main combustion zone relevantly. When the coal mills that were in the middle and above floors were in the operation, the denitration by spraying mnmonia was not good. The air staging eom- bined with spraying ammonia in the main combustion zone technology could reach 75% of denitration rate.