| Mechanical and Energy Engineering |
|
|
|
|
| Solve CO inhibition of SNCR reaction by additive MMT |
| ZHOU Hao, SHI Wei, ZHU Guo dong |
| State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou 310027, China |
|
|
|
Abstract The effect of additive MMT and CO on selective non catalytic reduction (SNCR) were studied by experiment. The influences of MMT and CO synergy on SNCR NOx removal efficiency and CO emission concentration were mainly investigated. The reaction mechanism of additive MMT in SNCR system was also analyzed based on the experimental data. Results show that the optimum mass fraction of additive MMT is 40 mg/L. The reaction temperature region can be widened about 30 ℃ by adding MMT of 40 mg/L to SNCR reaction system where the urea acts as reducing agent. The optimum reaction temperature is 900 ℃ and the NOx removal efficiency is also increased. Adding CO can lower the SNCR reaction temperature, narrow the temperature region and reduce the maximum NOx removal efficiency. The higher the CO volume fraction is, the more obvious the changes will be. When the volume fraction of CO in simulated flue gas is increased from 0 to 800 μL/L, the NOx removal efficiency decreases from 83% to 75% and the optimal removal temperature decreases from 950 ℃ to 800 ℃. In a SNCR system with existence of CO, additive MMT can not only improve the SNCR NOx removal efficiency in low temperature region, but also offset the CO inhibition on the SNCR NOx removal in the high temperature zone. Additive MMT can expand the width of NOx removal temperature region to 240 ℃ and increase the NOx removal efficiency. The maximum NOx removal efficiency increases from 83% to 89% when the volume fraction of CO is 0, from 80% to 85% when that is 200 μL/L, from 79% to 85% when that is 500 μL/L and from 75% to 83% when that is 800 μL/L.
|
|
Published: 31 December 2015
|
|
|
MMT添加剂解决CO对SNCR的抑制作用
通过实验研究MMT和CO添加剂对SNCR反应的影响,着重研究MMT和CO在协同作用下对SNCR脱硝效率和CO排放浓度的影响,通过实验数据分析MMT添加剂在SNCR体系中的反应机理.结果表明：喷入模拟烟气中MMT添加剂的最佳质量浓度为40 mg/L,将此质量浓度的MMT添加到以尿素为还原剂的SNCR反应体系中,可以使反应温度窗口拓宽约30 ℃,最佳反应温度为900 ℃,对应的脱硝效率得到提高；CO的存在会使SNCR反应窗口向低温区移动,反应窗口宽度变窄,最大脱硝效率降低,且CO浓度越高,变化越明显.当模拟烟气中CO的体积分数从0增加到800 μL/L时,NO脱除率从83%下降到75%,最佳脱除温度从950 ℃下降至800 ℃；在存在CO的SNCR体系中,MMT添加剂不仅可以提高低温区SNCR反应的脱硝效率,而且能够在高温区抵减CO对SNCR脱硝的抑制作用,扩宽脱硝温度窗口宽度至240 ℃,在反应窗口内提高脱硝效率,使得最大NO脱除率在CO体积分数为0μL/L时从83%增大至89%；在CO体积分数为200 μL/L时,最大NO脱除率从80%增大至85%；在CO体积分数为500 μL/L时,最大NO脱除率从79%增大至85%；在CO体积分数为800 μL/L时,最大NO脱除率从75%增大至83%.
|
|
| ［1］ 岑可法,姚强,骆仲泱,等.燃烧理论与污染控制［M］.北京:机械工业出版社,2004: 5-10.
［2］ RADOJEVIC M. Reduction of nitrogen oxides in flue gases ［J］. Environmental Pollution, 1998, 102(1):685-689.
［3］ JAVED M T, IRFAN N, GIBBS B M. Control of combustion generated nitrogen oxides by selective non catalytic reduction ［J］. Journal of Environmental Management, 2007, 83.
(3): 251-289.
［4］ YANG W J, CHEN Z C, ZHOU Z J, et al. Cost efficient nitrogen oxides control by a hybrid selective noncatalytic reduction and selective catalytic reduction system on a
utility boiler ［J］. Environmental Engineering Science, 2011, 28(5): 341-348.
［5］ 龚家猷,李庆.燃煤电厂SNCR与SCR联合脱硝工艺在国内的首次应用［J］.华北电力技术,2011(2): 31-34.
GONG Jia you, LI Qing. First joint application of SNCR&SCR technique in coal fired power plant ［J］. North China Electric Power. 2011(2): 31-34.
［6］ ROTA R,ZARMLO E F.Influence of oxygenated additives on the NOx out process efficiency ［J］.Fuel, 2003,82(7)： 765-770.
［7］ 高攀,路春美,韩奎华,等；添加剂协同选择性非催化还原NO的过程研究［J］.燃烧科学与技术,2008,14（4）: 333-337
GAO Pan, LU Chun mei, HAN Kui hua, et al. NO removal by adding additives in the selective non catalytic reduction process［J］.Combustion Science and Technology, 2008,14（4）:
333-337.
［8］ ZAMANSKY V M, LISSIANSKI V V, MALY P M, et al. Reactions of sodium species in the promoted SNCR process ［J］. Combustion and Flame,1999,117(4)：821-831.
［9］ NIU SH L,HAN K H,LU CH M.An experimental study on the effect of operating parameters and sodium additive on the NOx OUT process ［J］. Process Safety and Environmental Protection,2011,89(2)： 121-126.
［10］ 张彦文,蔡宁生,李振山.加入CH4促进SNCR过程的计算与机理分析［J］.热力发电,2005,34(12)： 9-12.
ZHANG Yan wen, CAI Ning shen, LI Zhen shan. Added CH4 promote SNCR process calculation and mechanism analysis ［J］. Thermal Power Generation, 2005,34(12)： 9-12.
［11］ BAE S W, ROH S A, KIM S D. NO removal by reducing agents and additives in the selective non catalytic reduction（SNCR） process ［J］.Chemosphere, 2006, 65(1)： 170-175.
［12］ ALZUETA M U, ROJEL H, KRISTENSEN P G.Laboratory study of the CO/NH3/NO/O2 system: implications for hybrid reborn/SNCR strategies ［J］. Energy and Fuels,1997,11(3)： 716-723.
［13］ 吕洪坤.选择性非催还还原与先进再燃技术的实验及机理研究［D］.杭州：浙江大学,2009:13-20.
LV Hong Kun. Experimental and mechanism study on selective non catalytic reduction and advanced reburning ［D］. Hangzhou: Zhengjiang University, 2009:13-20.
［14］ 曹庆喜.气体添加剂对选择性非催化还原脱硝反应过程影响的研究［D］.哈尔滨：哈尔滨工业大学,2009:22-30.
CAO Qing xi. Effects of gaseous additives for selective non catalytic reduction of NOx ［D］. Harbin: Harbin Institute of Technology, 2009: 22-30.
［15］ 陈军锋.MMT对三效催化剂性能影响的实验研究［D］. 北京：清华大学,2011: 13.
CHEN Jun feng. Experimental Study on Influence of MMT on Three way Catalyst ［D］. Beijing: Tsinghua University, 2011: 13.
［16］ 朱云霞.茂基锰高效汽油添加剂［J］.精细石油化工文摘,1999,04: 72-76.
ZHU Yun xia. Cyclopentadienyl manganese efficient gasoline additive ［J］. Advances in Fine Petrochemicals, 1999,04: 72-76.
［17］ LYRAM D R. Environmental assessment of MMT fuel additive ［J］. The Science of the Total Environmental,1990,93: 107-144.
［18］ 冯永明.MMT对汽车尾气影响的实验研究［D］.北京：北京化工大学,2005: 26-34
FENG Yong ming. A fleet test study on effect of MMT fuel additive on vehicles emissiom ［D］. Beijing: Beijing University of Chemical Technology, 2005:26-34.
［19］ 殷红,李清毅,陈丰,等.MMT对煤燃烧飞灰含碳量和NOx排放的影响［J］.能源工程,2011,4: 45-50.
YIN Hong, LI Qing yi, CHEN Feng, et al. Effect of adding MMT to the coal on carbon content in fly ash and the NOx emission ［J］. Energy and Environment, 2011,4: 45-50.
［20］ JAWED M T,NIMMO W,GIBBS B M.Experimental and modeling study of the effect of CO and H2 on the urea Lenox process in a 150 kW laboratory reactor ［J］.Chemosphere,2008,70(6)：1059-1067.
［21］ LODDER P,LEFERS J B.Effect of natural gas, C2H6 and CO on the homogenous gas phase reduction of NOx by NH3 ［J］.The Chemical Engineering Journal, 1985, 30(3): 161-167.
［22］ ALZUETA M U,BILBAO R,MILLERA A,et al.Impact of new findings concerning urea thermal decomposition on the modeling of the urea SNCR process ［J］.Energy and Fuels,2000, 14(2)： 509-510.
［23］ RENATO R, DOROTA A, EVERTON F Z, et al. Experimental and modeling analysis of the NOxOUT processs ［J］. Chemical Engineering Science, 2002,57(1): 27-38.
［24］ HAN K H,LU C M.Kinetic model and simulation of promoted selective non catalytic reduction by sodium carbonate ［J］. Chinese Journal of Chemical Engineering,2007,15(4)： 512-519.
［25］ 周昊,张志中,鲍强,等. 添加剂对NOxOUT脱硝及N2O、CO生成的影响特性［J］. 化工学报,2014,65(6): 2232-2240.
ZHOU Hao, ZHANG Zhi zhong, BAO Qiang,et al. Influence of additives on NOxOUT denitration and formation of N2O and CO ［J］. CIESC Journal, 2014,65(6): 2232-2240.
［26］ WANG Z H, ZHOU J H, ZHANG Y W, et al. Experiment and mechanism investigation on advanced reburning for NOx reduction: influence of CO and temperature ［J］. Journal of Zhejiang University. Science B, 2005, 3（3）: 187-194.
［27］ LIU Y P, YUAN J J, LIN P Y,et al. Catalytic activity of nanocrystalline manganese oxides for CO oxidation ［J］. Chinese Journal of Cheamal Physics, 1999, 12(1): 83-85. |
|
Viewed |
|
|
|
Full text
|
|
|
|
|
Abstract
|
|
|
|
|
Cited |
|
|
|
|
| |
Shared |
|
|
|
|
| |
Discussed |
|
|
|
|
