成型条件对Co/ZSM-5催化剂催化分解N_2O性能影响

Effect of forming conditions on the performance of catalytic decomposition of N_2O over Co/ZSM-5 catalyst

采用挤条成型法制备Co/ZSM-5催化剂,通过X射线衍射、BET比表面积、氢气程序升温还原(H_2-TPR)、氨气程序升温脱附法(NH_3-TPD)和颗粒径向抗压碎(侧压)强度测试对催化剂进行表征,在固定床微型反应器中评价催化剂催化分解N_2O活性,对Co/ZSM-5(N-50)催化剂进行稳定性测试。结果表明,钴物种以Co3O4尖晶石氧化物形式存在于Co/ZSM-5催化剂中,胶溶剂种类显著影响催化剂抗压碎强度;黏合剂用量影响催化剂抗压碎强度、酸量、氧化还原性和催化剂催化分解N_2O活性;以硝酸为胶溶剂,黏合剂(SB粉)用量为30%和50%制备的催化剂,抗压碎强度大,分别为208N/cm和230N/cm,催化分解N_2O温度T95分别为485℃和500℃。在固定床微型反应器中,模拟工业尾气组成(φN_2O=11%、φO_2=16%、N_2为平衡气),反应温度446℃、空速6000h-1条件下,Co/ZSM-5(N-50)催化剂在1000h稳定性测试中表现出良好的催化活性和稳定性,N_2O转化率高于98%。

The Co/ZSM-5 catalysts were prepared by extruding strip forming method and were characterized by XRD, BET, H2-TPR, NH3-TPD and particle radial crushing(side pressure) strength tests. The activity stability tests of the catalysts for catalytic decomposition of N2 O were carried out in a fixed-bed micro reactor. It was found that the cobalt spices in the catalysts were Co3 O4 and the type of peptizers obviously influenced the mechanical strength of catalysts. The amount of adhesive also influenced the mechanical strength, the amount of acid centers, redox properties and the activities of the catalysts. Co/ZSM-5(N-50) catalyst was prepared with nitric acid as peptizer and SB powder(mass fractionof30%and50%)asadhesive.Ithasstrongmechanicalstrength(208 N/cmand230 N/cm,respectively)and the T95 for N2 O decomposition were 485℃ and 500℃, respectively. Under the simulated industrial tail gas(φN2 O=11%, φO2=16% and N2 as balance gas) condition, when the reaction temperature was 446℃ and space velocity was 6000 h-1 in the fixed-bed micro reactor, the Co/ZSM-5(N-50) catalyst showed prominent stability, and the N2 O decomposition conversion was above 98% in a 1000 h test.