-
摘要: 在模拟SCR反应器烟气组分下, 考察了过渡金属改性掺杂对SCR催化剂单质汞 (Hg0) 氧化性能的影响。采用N2吸附-脱附和X射线衍射 (XRD) 对催化剂理化性能进行表征。结果表明, 金属改性掺杂减小了催化剂的比表面积和总孔容, 但对催化剂的孔径分布没有太大的影响。XRD谱图中出现了微弱的过渡金属氧化物衍射峰。8% Ce/SCR和8% Cu/SCR催化剂表现出了相对稳定和高效的Hg0氧化效率, 而8% Co/SCR催化剂Hg0氧化效率受温度影响较大。金属改性掺杂的催化剂在低NH3和NO烟气组分中表现出较好的Hg0氧化效率, 当烟气组分中存在HCl时, 促进更加明显; 而当催化剂在高NH3和NO烟气组分条件下, 即使有HCl的存在对Hg0氧化效率影响也不大。Abstract: The oxidation activity of elemental mercury (Hg0) by transition metal modified SCR catalysts was investigated by using the simulated SCR reactor. The physical and chemical properties of the catalysts were characterized by N2 adsorption-desorption and X-ray diffraction (XRD). The results show that the specific surface area and total pore volume of the catalysts are decreased after the modification by metal oxide. However, the pore structure and distribution after modification have little variation. The weak diffraction peaks of transition metal oxide can be seen from the XRD pattern. Both 8% Ce/SCR and 8% Cu/SCR catalysts show a relatively stable and high Hg0 oxidation efficiency, while the oxidation activity of the 8% Co/SCR catalyst is greatly influenced by temperature. The modified SCR catalysts have an excellent catalytic performance for the Hg0 oxidation under a lower concentration of NH3 and NO. And the Hg0 oxidation efficiency is promoted significantly in the presence of HCl. On the contrary, there is little improvement in the Hg0 oxidation by HCl at the condition of higher concentration of NH3 and NO.
-
Key words:
- metal modifier /
- SCR catalyst /
- Hg0 oxidation
-
图 2 改性SCR催化剂对Hg0氧化效率的影响
Figure 2 Hg0 oxidation efficiency over modified SCR catalysts
(a): condition T1; (b): condition T2
图 3 HCl存在条件下改性SCR催化剂对Hg0氧化效率的影响
Figure 3 Hg0 oxidation efficiency over modified SCR catalysts in the presence of HCl
(a): condition T1+45 mg/m3 HCl; (b): condition T2+45 mg/m3 HCl
图 5 催化剂的N2吸附-脱附曲线
Figure 5 N2 adsorption-desorption curves of catalyst samples
(a): N2adsorption-desorption isotherms; (b): pore size distributions
表 1 测试条件
Table 1 Test conditions
Simulated flue gas components Balance gas Temperature t/℃ T1 5%O2+348mg/m3NH3+613mg/m3NO+1780mg/m3SO2 N2 300-400 T2 5%O2+35mg/m3NH3+61mg/m3NO+1780mg/m3SO2 N2 300-400 
下载: 导出CSV
表 2 催化剂的比表面积和孔结构
Table 2 Specific surface area and pore structure of the catalysts
Catalyst Specific surface area
A/(m2·g -1)Pore volume
v/(cm3·g-1)Average pore diameter d/nm Raw SCR 85.8 0.277 11.3 8% Ce /SCR 69.1 0.216 11.1 8% Cu /SCR 59.8 0.238 14.0 8% Co /SCR 67.2 0.226 11.6
下载: 导出CSV
-
[1] LI P, FENG X B, QIU G L, SHANG L H, LI Z G. Mercury pollution in Asia:A review of the contaminated sites[J]. J Hazrad Mater, 2009, 168(2/3):591-601. https://www.researchgate.net/profile/Zhonggen_Li/publication/24256386_Mercury_pollution_in_Asia_A_review_of_the_contaminated_sites/links/0a85e534161cb3cd12000000.pdf [2] SENIOR C L, HELBLE J J, SAROFIM A F. Emissions of mercury, trace elements, and fine particles from stationary combustion sources[J]. Fuel Process Technol, 2000, 65-66(0):263-288. [3] PRESTO A A, GRANITE0 E J. Survey of catalysts for oxidation of mercury in flue gas[J]. Environ Sci Technol, 2006, 40(18):5601-5609. doi: 10.1021/es060504i [4] 刘玲, 段钰锋, 王运军, 王卉, 尹建军.两种煤在热解过程中汞的析出和形态分布实验研究[J].燃料化学学报, 2010, 38(2):134-139. doi: 10.1016/S1872-5813(10)60026-6LIU Ling, DUAN Yu-feng, WANG Yun-jun, WANG Hui, YIN Jian-jun. Experimental study on mercury release behavior and speciation during pyrolysis of two different coals[J]. J Fuel Chem Technol, 2010, 38(2):134-139. doi: 10.1016/S1872-5813(10)60026-6 [5] PENG Y, SI W Z, LI X, LUO J M, LI J H, CRITTENDEN J, HAO J M. Comparison of MoO3 and WO3 on arsenic poisoning V2O5/TiO2 catalyst:DRIFTS and DFT study[J]. Appl Catal B:Environ, 2016, 181:692-698. doi: 10.1016/j.apcatb.2015.08.030 [6] PUDASAINEE D, LEE S J, LEE S H, KIM J H, JANG H N, CHO S J, SEO Y C. Effect of selective catalytic reactor on oxidation and enhanced removal of mercury in coal-fired power plants[J]. Fuel, 2010, 89(4):804-809. doi: 10.1016/j.fuel.2009.06.022 [7] CAO Y, GAO Z Y, ZHU J S, WANG Q H, HUANG Y J, CHIU C C, PARKER B, CHU P, PAN W P. Impacts of halogen additions on mercury oxidation, in a slipstream selective catalyst reduction (SCR), reactor when burning sub-bituminous coal[J]. Environ Sci Technol, 2008, 42(1):256-261. doi: 10.1021/es071281e [8] CAO Y, C B, WU J, CUI H, SMITH J, CHEN C K, CHUP, PAN W P. Study of mercury oxidation by a selective catalytic reduction catalyst in a pilot-scale slipstream reactor at a utility boiler burning bituminous coal[J]. Energy Fuels, 2007, 21:145-156. doi: 10.1021/ef0602426 [9] YANG H M, PAN W P. Transformation of mercury speciation through the SCR system in power plants[J]. J Environ Sci, 2007, 19(2):181-184. doi: 10.1016/S1001-0742(07)60029-1 [10] SENIOR C L. Oxidation of mercury across selective catalytic reduction catalysts in coal-fired power plants[J]. J Air Waste Manage, 2006, 56(1):23-31. doi: 10.1080/10473289.2006.10464437 [11] KAMATA H, UENO S I, NAITO T, YUKIMURA A. Mercury oxidation over the V2O5(WO3)/TiO2 commercial SCR catalyst[J]. Ind Eng Chem Res, 2008, 47(21):8136-8141. doi: 10.1021/ie800363g [12] YANG J, YANG Q, SUN J, LIU Q C, ZHAO D, GAO W, LIU L. Effects of mercury oxidation on V2O5-WO3/TiO2 catalyst properties in NH3-SCR process[J]. Catal Commun, 2015, 59:78-82. doi: 10.1016/j.catcom.2014.09.049 [13] 李建荣, 何炽, 商雪松, 陈进生, 喻小伟, 姚沅君. SCR脱硝催化剂对烟气中零价汞的氧化效率研究[J].燃料化学学报, 2012, 40(2):241-246. doi: 10.1016/S1872-5813(12)60012-7LI Jian-rong, HE Chi, SHANG Xue-song, CHEN Jin-sheng, YU Xiao-wei, YAO Yuan-jun. Oxidation efficiency of elemental mercury in flue gas by SCR De-NOx catalysts[J]. J Fuel Chem Technol, 2012, 40(2):241-246. doi: 10.1016/S1872-5813(12)60012-7 [14] LI H L, LI Y, WU C Y, ZHANG J Y. Oxidation and capture of elemental mercury over SiO2-TiO2-V2O5 catalysts in simulated low-rank coal combustion flue gas[J]. Chem Eng J, 2011, 169(1/3):186-193. [15] LI H L, WU C Y, LI Y, ZHANG J Y. Superior activity of MnOx-CeO2/TiO2 catalyst for catalytic oxidation of elemental mercury at low flue gas temperatures[J]. Appl Catal B:Environ, 2012, 111-112:381-388. doi: 10.1016/j.apcatb.2011.10.021 [16] XU W X, WANG H R, ZHOU X, ZHU T Y. CuO/TiO2 catalysts for gas-phase Hg0 catalytic oxidation[J]. Chem Eng J, 2014, 243:380-385. doi: 10.1016/j.cej.2013.12.014 [17] LI H L, WU S K, WU C Y, WANG J, LI L Q, SHIH K. SCR atmosphere induced reduction of oxidized mercury over CuO/CeO2-TiO2 catalyst[J]. Environ Sci Technol, 2015, 49(12):7373-7379. doi: 10.1021/acs.est.5b01104 [18] DRANGA B A, KOESER H. Increased co-oxidation activity for mercury under hot and cold site coal power plant conditions-Preparation and evaluation of Au/TiO2-coated SCR-DeNOx catalysts[J]. Appl Catal B:Environ, 2015, 166-167:302-312. doi: 10.1016/j.apcatb.2014.11.018 [19] WANG P Y, SU S, XIANG J, CAO F, SUN L S, HU S, LEI S Y. Catalytic oxidation of Hg0 by CuO-MnO2-Fe2O3/γ-Al2O3 catalyst[J]. Chem Eng J, 2013, 225(0):68-75. [20] WEN X Y, LI C T, FAN X P, GAO H L, ZHANG W, CHEN L, ZENG G M, ZHAO Y P. Experimental study of gaseous elemental mercury removal with CeO2/γ-Al2O3[J]. Energy Fuels, 2011, 25(7):2939-2944. doi: 10.1021/ef200144j [21] XIE Y N, LI C T, ZHAO L K, ZHANG J, ZENG G M, ZHANG X N, ZHANG W, TAO S S. Experimental study on Hg0 removal from flue gas over columnar MnOx-CeO2/activated coke[J]. Appl Surf Sci, 2015, 333:59-67. doi: 10.1016/j.apsusc.2015.01.234 [22] WANG J W, YANG J L, LIU Z Y. Gas-phase elemental mercury capture by a V2O5/AC catalyst[J]. Fuel Process Technol, 2010, 91(6):676-680. doi: 10.1016/j.fuproc.2010.01.017 [23] 赵莉, 何青松, 李琳, 陆强, 董长青, 杨勇平.改性SCR催化剂对Hg0催化氧化性能的研究[J].燃料化学学报, 2015, 43(5):628-634. doi: 10.1016/S1872-5813(15)30018-9ZHAO Li, HE Qing-song, LI Lin, LU Qiang, DONG Chang-qing, YANG Yong-ping. Research on the catalytic oxidation of Hg0 by modified SCR catalysts[J]. J Fuel Chem Technol, 2015, 43(5):628-634. doi: 10.1016/S1872-5813(15)30018-9 [24] LIU Y, WANG Y J, WANG H Q, WU Z B. Catalytic oxidation of gas-phase mercury over Co/TiO2 catalysts prepared by sol-gel method[J]. Catal Commun, 2011, 12(14):1291-1294. doi: 10.1016/j.catcom.2011.04.017 [25] HONG H J, HAM S W, KIM M H, LEE S M, LEE J B. Characteristics of commercial selective catalytic reduction catalyst for the oxidation of gaseous elemental mercury with respect to reaction conditions[J]. Korean J Chem Eng, 2010, 27(4):1117-1122. doi: 10.1007/s11814-010-0175-x [26] LEE W, BAE G N. Removal of elemental mercury (Hg (0)) by nanosized V2O5/TiO2 catalysts[J]. Environ Sci Technol, 2009, 43(5):1522-1527. doi: 10.1021/es802456y [27] GAO X, JIANG Y, ZHONG Y, LUO Z Y, CEN K F. The activity and characterization of CeO2-TiO2 catalysts prepared by the sol-gel method for selective catalytic reduction of NO with NH3[J]. J Hazrad Mater, 2010, 174:734-739. doi: 10.1016/j.jhazmat.2009.09.112 -
点击查看大图
图(6) / 表(2)
计量
- 文章访问数: 464
- HTML全文浏览量: 67
- PDF下载量: 7
- 被引次数: 0
