CH_4对于尿素选择性非催化还原脱硝的影响研究  

Investigation on the effects of CH4on urea selective non-catalytic reduction denitration process

作　　者：熊建国 吕洪坤 韩高岩 肖海平[2] XIONG Jianguo;LYU Hongkun;HAN Gaoyan;XIAO Haiping(Zhejiang Electric Power Research Institute,Hangzhou Zhejiang 310014;School of Energy,Power and Mechanical Engineering,North China Electric Power University,Beijing 102206)

机构地区：[1]浙江省电力科学研究院,浙江杭州310014 [2]华北电力大学能源动力与机械工程学院,北京102206

出　　处：《环境污染与防治》2018年第2期161-164,169,共5页Environmental Pollution & Control

基　　金：国家自然科学基金资助项目(No.51206047)

摘　　要：在加热的石英反应器中研究CH_4对于模拟烟气尿素选择性非催化还原(SNCR)脱硝过程的影响。结果表明:添加CH_4可使脱硝曲线向低温方向移动,提高低温下的脱硝效率及脱硝温度窗口宽度,但最佳脱硝效率略有降低,当CH_4添加比由0增大到6.0时,尿素SNCR最佳脱硝效率减少了近14百分点,最佳脱硝温度降低了200℃,当CH_4添加比为2.0时脱硝温度窗口宽度最大,为296℃;添加CH_4可以缓解尿素SNCR体系的NH_3、HNCO逃逸,NH3、HNCO的近零排放温度均下降约150℃,为控制CH_4逃逸,喷入CH_4时应尽量保证喷入处温度不低于850℃;添加CH_4会提高低温下尿素SNCR的N_2O生成浓度,因此低温下N_2O的排放问题要引起足够重视;温度低于1 000℃时,提高氨氮比可以增强CH_4对脱硝效率的促进作用,但高于1 000℃时则起抑制作用。The effects of CH 4 addition on urea selective non-catalytic reduction(SNCR)denitration in simulated flue gas were investigated in a heated quartz tube reactor.The results showed that adding CH4 not only made the denitration curve move to low temperature,but also improved the denitration efficiency at low temperature and the width of denitration temperature window,while the best denitration efficiency dropped slightly;when CH4 additive proportion increased from 0 to 6.0,the best denitration efficiency of urea SNCR decreased by 14 percent points,the corresponding temperature reduced by 200℃;when CH4 additive proportion was 2.0,the width of denitration temperature window reached the peak value of 296℃.Adding CH4 could relieve the escape of NH 3,HNCO in urea SNCR system;the near-zero emission temperature of NH 3 and HNCO were both dropped about 150℃,when CH4 was sprayed into the flue gas;the temperature was better not lower than 850℃to prevent CH4 escape.Adding CH4 would improve the concentration of N 2O at low temperature,so the emission of N 2O at low temperature should be paid enough attention.Improving ammonia nitrogen ratio enhanced the promoting effect of CH 4 on the denitration efficiency when the temperature was below 1 000℃,but it could inhibit the promoting effect when the temperature above 1 000℃.

关 键 词：尿素选择性非催化还原脱硝 CH4 脱硝效率 NH3 N2O 

分 类 号：X773[环境科学与工程—环境工程]