条状超细镍基负载型催化剂性能研究

用溶胶-凝胶法制备了Ni/TiO_2-SiO_2催化剂粉状前驱体,挤条成型,预还原后用于苯加氢反应,其比表面积和孔容分别达到349 m~2·g~(-1)和0.35 cm~3·g~(-1)。采用BET、XRD和TEM对催化剂物化性能进行表征。利用脉冲氢吸附法考察催化剂中活性组分镍的表面分散度。在固定床微反装置上,以噻吩为毒物,考察了催化剂抗硫中毒性能。在100 mL中试装置上,考察了预还原后催化剂的苯加氢反应的活性、选择性和热稳定性能。实验结果表明,条状Ni/TiO_2-SiO_2催化剂有较大的比表面积,单一的孔径分布,活性组分镍高度分散。每克镍上极限耐硫量达到467.25 μL噻吩。在试验条件下,催化剂能在较宽的温度和液苯空速范围使用,经25天运转,进行100 h催化老化实验,催化剂的比表面性能无显著变化。

Study on behaviors of extruded supported ultra fine nickel catalysts

Ni/TiO2-SiO2 catalyst was prepared by sol-gel method and shaped by extrusion, with surface area of 349 m^2·g^-1 and pore volume of 0.35 cm^3·g^-1. The catalyst was characterized by BET, XRD and TEM. Dispersity of active nickel over surface of the catalyst was investigated by H2 pulse adsorption. Sulfur tolerance of the catalyst was tested by thiophene in a fixed-bed micro-reactor. The pre-reduced samples were used as the catalyst for benzene hydrogenation. The activity, selectivity to cyclohexane and thermal stability of the catalyst were studied in a 100 mL micro-reactor. The results showed that extruded Ni/TiO2-SiO2 catalyst had larger surface area, narrow pore size distribution and highly dispersed active nickel, with upper limit sulfur tolerance of 467.25μL·g^-1. The Ni/TiO2-SiO2 catalyst could be used in wide range of temperature and benzene LHSV, without noticeable change in BET surface area after 25 days of run followed by 100 h accelerated aging.