摘要
以共沉淀法合成了硅铝系载体(AS和SA),并采用改性天然高铝石为原料合成了矿物质载体(MC 1和MC 2),采用浸渍法合成了镍负载型催化剂。用常压固定床管式反应器,考察了液化石油气水蒸气重整反应活性,通过XRD、物理吸附等手段对催化剂进行了表征。结果表明,以MC 1、MC 2和SA、AS为载体的催化剂的水蒸气重整活性明显高于目前普遍使用的Ni α Al2O3催化剂。以SA为载体,负载5%镍的催化剂具有最好的水蒸气重整活性。在750℃,水碳比为2.0的条件下转化率达100%,C1选择性达94.46%。XRD分析结果表明1300℃焙烧后的SA载体中存在α Al2O3晶型和莫来石结构。硅、铝添加次序对水蒸气重整活性影响较大,硅 铝添加次序的催化剂样品的活性高于铝 硅添加次序的样品,C1选择性提高12.7%。
This work aims at exploiting a kind of catalyst as a substitute of imported catalyst for LPG steam reforming. The Ni based catalysts were prepared by impregnation of nickel nitrate solutions on four kinds of supports respectively. Support SA was prepared by co-precipitation from a mixture of the solutions of Na_2SiO_3·6H_2O and Al(NO_3)_3·9H_2O by means of a solution of NH_4·H_2O at 343K and pH=6.5. Support AS was prepared in different precipitation sequence compared with support SA. Support MC,s were prepared with modified natural mineral as raw materials. MC-1 was calcined at 1100℃ and MC-2 at 900℃. The LPG steam reforming reactions were carried out at atmosphere in a continuous -flow type fixed-bed reactor. The effects of supports on steam reforming activity are investigated. X-ray Differaction (XRD), Thermal Gravity-Differential Thermal Gravity (TG-DTG) and Transmission Electron Microscope (TEM) are used to characterize the catalysts. The catalytic activity of the catalysts were studied at 750℃ and water/hydrocarbon=2.0. The results were as follows: the catalysts prepared in our lab have excellent activity for LPG steam reforming reaction compared to the traditional Ni/α-Al_2O_3 catalyst. The activity of Ni/SA catalyst was superior to others. Under the optimized experimental condition, 100% conversion and 94.46% selectivity were obtained. Support SA calcined at 1300℃ was mainly composed of α-Al_2O_3 and Si_2Al_6O_13 crystal. The precipitation sequence of supports significantly affected the catalyst activity. The catalyst prepared with Si-Al precipitation sequence is better than that of Al-Si sequence.
出处
《燃料化学学报》
EI
CAS
CSCD
北大核心
2004年第3期357-361,共5页
Journal of Fuel Chemistry and Technology
基金
大连市科委资助项目(1998 124) ~~
