新型双流化床炉内NOx生成特性数值模拟  

Simulation of NO_x formation in novel dual circulating fluidized-bed boiler

作　　者：张弋 李建波[1] 王泉海[1] 卢啸风[1] ZHANG Yi;LI Jianbo;WANG Quanhai;LU Xiaofeng(Key Laboratory of Low-grade Energy Utilization Technologies and Systems of the Ministry of Education of China,Chongqing University,Chongqing 400044,China;Chongqing General Industry(Group)CO.,LTD.,Chongqing 400044,China)

机构地区：[1]“低品位能源利用技术及系统”教育部重点实验室,重庆大学,重庆400044 [2]重庆通用工业(集团)有限责任公司,重庆400044

出　　处：《化工学报》2018年第4期1703-1713,共11页CIESC Journal

基　　金：中央高校基本科研业务费专项资金(0903005203564)。

摘　　要：运用煤燃烧及NO_x生成的详细化学反应机理,通过搭建一维化学反应器网络(1D-CRN),对一个新型双流化床(DCFB)内燃料型N转化为NO_x的基元化学反应进行了敏感性分析并讨论了反应温度、过量空气系数以及一、二次风配比对燃料型NO_x生成的影响。研究发现,在相同条件下,循环流化床炉膛出口的NO_x排放值为224.48mg·m^(-3),而双流化床炉膛出口的NO_x排放值为97.29 mg·m^(-3),双流化床对于燃料型NO_x的减排幅度达到了56.66%。此外,促进NO_x生成的基元反应主要有R398(NH_2+O→HNO+H)、R1-N-1(N-Vol→NH_3+HCN)、R569(NCO+O_2NO+CO_2)、R17(H+O_2O+OH)等反应,而抑制NO_x生成的反应包括R411(NH_2+NON_2+H_2O)、R412(NH_2+NONNH+OH)、R570(NCO+NON_2O+CO)、R571(NCO+NON_2+CO_2)以及R5(Char+NO→Char+N_2+O_2)和R6(Soot+NO→n Soot+N_2+CO)等反应。这说明反应区域氧气浓度是影响NO_x生成的关键,低氧浓度可抑制燃料N向NO_x转化。另外,NO_x生成值随着反应温度的升高而降低,但随着过量空气系数和一次风所占比例的增大而增加。The NOx formation of a novel dual circulating fluidized-bed(DCFB)boiler were numerically studied based on the detailed chemical reaction mechanism in a one dimensional chemical reaction network(1D-CRN).The sensitivity of NOx formation and the effect of reaction temperature,excess air ratio and primary air ratio were investigated.The results indicated that the NOx emission of traditional CFB was calculated to be 224.48 mg·m-3,while the value of DCFB was 97.29 mg·m-3,indicating that DCFB would reduce the NOx formation.In addition,the sensitivity analysis showed that the reactions such as R398,R1-N-1,R569 and R17 promoted NOx formation,while those including R411,R412,R570,R571,R5 and R6 inhibited NOx formation.Moreover,it was revealed that oxygen in the reaction zone was one contributing factor to NOx formation by the fact that less oxygen in the reaction zone would inhibit NOx formation.Likewise,NOx formation decreased with increasing reaction temperature but increased with increasing excess air ratio and primary air ratio.

关 键 词：循环流化床 煤燃烧 NOx生成 详细化学反应机理 模拟 

分 类 号：TQ517.3[化学工程]