新型固定床Raney Ni催化剂的苯加氢活性及耐硫性

将新型固定床Raney Ni催化剂应用于苯加氢反应,研究了反应温度、氢气压力、液态空速、氢与苯的摩尔比及催化剂预处理温度对苯加氢反应的影响,在适宜的条件下进行了200h连续运转,并与负载型Ni催化剂的活性进行了对比。实验结果表明,新型固定床Raney Ni催化剂具有较大的活性金属Ni比表面积,当氢与苯的摩尔比为6∶1时,在80~120℃、0.5~1.0MPa、液态空速2.0h-1的缓和条件下即可实现苯的完全转化。新型固定床Raney Ni催化剂具有较好的耐硫性能,每毫升催化剂可耐受8 001μg的硫,远优于负载型Ni催化剂。X射线衍射和扫描电子显微镜-能量色散X射线分析结果表明,硫、氯等杂质吸附中毒及反应温度过高使Ni晶粒聚结是新型固定床Raney Ni催化剂失活的主要原因。

Activity of Novel Raney Ni Catalyst for Fixed-Bed in Benzene Hydrogenation and Its Sulfur Resistance

Novel Raney Ni catalyst for fixed-bed was prepared and benzene hydrogenation was taken as probe reaction to evaluate its activity.Effects of reaction temperature,pressure,liquid hourly space velocity(LHSV),mole ratio of hydrogen to benzene and pretreatment temperature of the catalyst on hydrogenation were investigated.The hydrogenation had been carried out continuously under appropriate conditions for 200 h.Activity of the novel catalyst was compared with two domestic supported Ni catalysts.The active metallic Ni specific surface area of novel catalyst is much larger and on it benzene can be completely hydrogenated into cyclohexane under mild reaction conditions of temperature 80-120 ℃,hydrogen pressure 0.5-1.0 MPa,LHSV 2.0 h-1 and n(H2) ∶n(benzene) 6 ∶1.Capacity of sulfur resistance of the catalyst reaches 8 001 μg sulfur per mL catalyst far superior to the two supported catalysts.XRD and SEM-EDX results showed that catalyst deactivation is mainly due to adsorption of poisonous sulfur and chlorine,and aggregation of Ni particles at high temperature.