Ni/γ-Al_2O_3催化剂制备条件的优化及对萘饱和加氢反应的影响

Effects of preparation conditions for Ni/γ-Al_2O_3 catalyst on saturated hydrogenation of naphthalene

采用浸渍法,改变镍负载量、焙烧温度和焙烧时间等条件制备了Ni/Al_2O_3系列催化剂,使用高压固定床反应器评价了优化后的Ni/Al_2O_3催化剂在萘饱和加氢反应中的性能,并进行了200 h的稳定性实验。采用XRD,H2-TPR,SEM,TG,DTA,BET等方法对催化剂进行了表征。表征结果显示,在镍负载量为10%(w)、焙烧温度为450℃、焙烧时间为4 h的条件下,制备的催化剂加氢性能较高,活性组分Ni O与γ-Al_2O_3载体间存在相互作用且高度分散于载体表面。实验结果表明,在反应压力为5 MPa、反应温度为260/275℃、LHSV=1 h-1、氢油体积比为300∶1的反应条件下,采用优化后的Ni/Al_2O_3催化剂,十氢萘的选择性最高可达99%以上,产物中顺式和反式十氢萘的比例可达3.0。

Ni/Al2O3 catalysts for the saturated hydrogenation of naphthalene to decahydronaphthalene were prepared by the impregnation method. The effects of calcination temperature, calcination time and Ni loading on the ratio of trans-decahydronaphthalene to cis-decahydronaphthalene in the hydrogenation products were investigated in a fixed bed reactor. The stability of the catalysts was researched. The Ni/Al2O3 catalysts were characterized by means ofXRD, H2-TPR, SEM, TG-DTA and BET. It was showed that, the appropriate preparation conditions for the Ni/Al2O3 catalysts were ： calcination temperature of450 ℃, calcination time of 4 h and Ni loading of 10%（w）. Under the reaction conditions of pressure 5 MPa, reaction temperature 260/275 ℃, LHSV 1 h-1 and V（H2） ： V（oil） 300 ： 1, the selectivity to decahydronaphthalene was more than 99% and the ratio of trans-decahydronaphthalene to cis-decahydronaphthalene in the hydrogenation products was around 3.0.