V_2O_5-WO_3-CeO_2/TiO_2催化剂的制备及其脱硝性能
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摘要
采用一步浸渍法和分步浸渍法分别制备了V_2O_5-WO_3-CeO_2/TiO_2催化剂,考查了其脱硝性能、抗SO_2中毒性能和脱硝活性稳定性,并通过SEM、EDS、XRD、激光拉曼等技术对催化剂进行了表征。实验结果表明:分步浸渍法制备的催化剂的脱硝活性优于一步浸渍法,且抗SO_2中毒能力更强;在m(V_2O_5)∶m(WO_3)∶m(CeO_2)∶m(TiO_2)=1∶5∶10∶100时催化剂脱硝活性最佳,且具有良好的脱硝活性稳定性。表征结果显示,分步浸渍法与一步浸渍法制备的催化剂晶型结构相差不大,而分步浸渍法制备的催化剂颗粒粒径更小、更均匀,催化剂中Ce、O、V和W元素的含量更高。
The V_2O_5-WO_3-CeO_2/TiO_2 catalysts were prepared by one-step impregnation method and stepwise impregnation method respectively. Their denitration activity,SO_2 poisoning resistance capability and denitration stability were investigated. The catalysts were characterized by SEM,EDS,XRD and Raman. The results showed that:The denitration activity and the SO_2 poisoning resistance capability of the catalysts prepared by stepwise impregnation method were better than the catalyst prepared by one-step impregnation method;When m(V_2O_5)∶m(WO_3)∶m(CeO_2)∶m(TiO_2)= 1∶5∶10∶100,the catalysts had the best denitration activity and good denitration stability. The characterization results showed that the crystal structure of the catalysts prepared by stepwise impregnation method was almost the same as that by one-step impregnation method,while the particle size was smaller and more uniform,and the content of Ce,O,V and W in the catalyst was higher.
The V_2O_5-WO_3-CeO_2/TiO_2 catalysts were prepared by one-step impregnation method and stepwise impregnation method respectively. Their denitration activity,SO_2 poisoning resistance capability and denitration stability were investigated. The catalysts were characterized by SEM,EDS,XRD and Raman. The results showed that:The denitration activity and the SO_2 poisoning resistance capability of the catalysts prepared by stepwise impregnation method were better than the catalyst prepared by one-step impregnation method;When m(V_2O_5)∶m(WO_3)∶m(CeO_2)∶m(TiO_2)= 1∶5∶10∶100,the catalysts had the best denitration activity and good denitration stability. The characterization results showed that the crystal structure of the catalysts prepared by stepwise impregnation method was almost the same as that by one-step impregnation method,while the particle size was smaller and more uniform,and the content of Ce,O,V and W in the catalyst was higher.
引文
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[4]蔺卓玮,陆强,唐昊,等.平板式V2O5-MoO3/TiO2型SCR催化剂的中低温脱硝和抗中毒性能研究[J].燃料化学学报,2017,45(1):113-122.
[5]中华人民共和国国家质量监督检验检疫总局,中国国家标准化管理委员会.工业锅炉经济运行标准:GB/T17954-2007[S].北京:中国标准出版社,2007.
[6]中华人民共和国国家质量监督检验检疫总局,中国国家标准化管理委员会.火电厂大气污染物排放标准:GB13223-2011[S].北京:中国环境科学出版社,2011.
[7]周惠.SCR脱硝催化剂V2O5-WO3/TiO2的性能及再生研究[D].南宁:广西大学,2016.
[8]周惠,黄华存,董文华.SiO2掺杂对V2O5-WO3/TiO2脱硝催化性能的影响[J].环境工程学报,2017,11(8):4677-4684.
[9]JIN R B,LIU Y,WU Z B,et al.Low-temperature selective catalytic reduction of NO with NH3 over MnCe oxides supported on TiO2 and Al2O3:a comparative study[J].Chemosphere,2010,78(9):1160-1166.
[10]QI G,YANG R T,CHANG R.Low-temperature SCR of NO with NH3 over USY-supported manganese oxide-based catalysts[J].Catal Lett,2003,87(1/2):67-71.
[11]JIANG L J,LIU Q C,ZHAO Q,et al.Promotional effect of Ce on the SCR of NO with NH3 at low temperature over MnO(x)supported by nitric acid-modified activated carbon[J].Res Chem Termedia,2018,44(3):1729-1744.
[12]XU B Q,XU H D,LIN T,et al.Promotional effects of Zr on K+-poisoning resistance of CeTiOx catalyst for selective catalytic reduction of NOx with NH3[J].Chin J Catal,2016,37(8):1354-1361.
[13]史荣会,董文威,韩祯,等.铁铈钛复合氧化物催化剂的制备及其选择性催化还原NO的性能[J].化工环保,2014,34(2):181-185.
[14]LI F X,XIE J L,ANG D,et al.Mechanistic study of Ce-modified MnO(x)/TiO2 catalysts with high NH3-SCR performance and SO2 resistance at low temperatures[J].Res Chem Intermedia,2017,43(10):5413-5432.
[15]YANG W,LIU Y X,WANG Q et al.Removal of elemental mercury from flue gas using wheat straw chars modified by Mn-Ce mixed oxides with ultrasonic-assisted impregnation[J].Chem Eng J,2017,326:169-181.
[16]QIU L,MENG J J,PANG D D,et al.Reaction and characterization of Co and Ce doped Mn/TiO2 catalysts for low-temperature SCR of NO with NH3[J].Catal Lett,2015,14(7):1500-1509.
[17]WANG H Q,CHEN X B,GAO S,et al.Deactivation mechanism of Ce/TiO2 selective catalytic reduction catalysts by the loading of sodium and calcium salts[J].Catal Sci Technol,2013,3(3):715-722.