丙烷在Ce-Fe/Al_2O_3/cordierite上选择性催化还原NO  

Selective catalytic reduction of NO by C_3H_8 over Ce-Fe/Al_2O_3/cordierite catalysts

作　　者：李伉锴 周皞[2] 苏亚欣[1] 袁旻昊[1] 邓文义[1] 赵兵涛[3] 

机构地区：[1]东华大学环境学院,上海201620 [2]常州工程职业技术学院,江苏常州213164 [3]上海理工大学能源动力学院,上海200093

出　　处：《燃料化学学报》2018年第1期99-109,共11页Journal of Fuel Chemistry and Technology

基　　金：国家自然科学基金(51278095);江苏省前瞻性联合研究项目(BY2015032-02);上海市自然科学基金(17ZR1419300)资助~~

摘　　要：利用凝胶溶胶法和浸渍法制备了Ce-Fe/Al_2O_3/cordierite催化剂,实验研究了其催化丙烷选择性还原NO的特性。结果表明,当铈的负载量从1%增加至5%时,Ce-Fe/Al_2O_3/cordierite的C_3H_8-SCR性能先增强后减弱,3.5Ce-Fe/Al_2O_3/cordierite具有最佳的脱硝性能,在有氧条件下,600℃时可实现96.5%的脱硝效率。Ce的加入能够提升Fe/Al_2O_3/cordierite催化剂的抗硫性能。烟气中通入0.02%的SO_2后,3.5Ce-Fe/Al_2O_3/cordierite催化丙烷还原NO的转化率始终维持在93%,而没有经过Ce修饰的Fe/Al_2O_3/cordierite的NO转化率从88%下降为80%左右。利用XRD、N_2吸附-脱附、SEM、H_2-TPR、吡啶吸附红外光谱等手段研究了催化剂的物理化学性质。结果表明,加入助剂铈能与Fe形成了固溶体,增加催化剂表面Lew is酸浓度和氧化还原能力,从而提高了催化丙烷还原NO的性能。过多的铈引入会减少Fe_2O_3结晶体的形成,不利于在C_3H_8-SCR反应中形成NO_2/NO_3^-物种,从而导致NO还原效率下降。A series of monolithic cordierite-based Ce-Fe/Al2O3 catalysts were prepared by sol-gel and impregnation method.The selective catalytic reduction of NO with C3H8 over the catalysts were experimentally studied.Results indicated that when the addition of cerium increased from 1% to 5%,the C3H8-SCR of Ce-Fe/Al2O3/cordierite increased at first then decreased and 3.5 Ce-Fe/Al2O3/cordierite showed the highest C3H8-SCR activity with 96.5% NO reduction in the presence of oxygen at 600 ℃.Cerium was able to improve the resistance to SO2 in the flue gas for the Fe/Al2O3/cordierite catalysts.When 0.02% SO2 was fed into the flue gas during the test,the NO reduction by 3.5 Ce-Fe/Al2O3/cordierite with C3H8 was always kept at about 93%,while the NO reduction by the catalyst without Ce,i.e.,Fe/Al2O3/cordierite,decreased from 88% to 80%.The catalysts were characterized using XRD,N2 adsorption-desorption,SEM,H2-TPR and Py-FTIR spectra of adsorbed pyridine.Results showed that the addition of cerium to iron oxide could form the solid solution,which could increase the Lewis acid concentration and redox property of the catalyst,thus improving the performance of catalytic reduction of NO with C3H8.However,the introduction of too much cerium would reduce the crystallinity of iron oxide nanorods,then inhibited the formation of the NO2/NO3^- species in the C3H8-SCR reaction,resulting in a decrease in the efficiency of NO reduction.

关 键 词：选择性催化还原 NO Fe/Al2O3/cordierite催化剂 铈 丙烷 

分 类 号：X511[环境科学与工程—环境工程]