摘要
以MoO3为前躯体,CH4/H2为还原碳化气,采用自制的程序升温还原碳化反应装置制备出Mo2C催化剂,并用XRD、BET进行表征.借助原位TGDTA方法研究了MoO3在CH4/H2气氛中的还原碳化历程和适宜的还原碳化温度.以噻吩/环己烷溶液为模型反应物,采用高压微反色谱实验装置考察了制备的碳化钼催化剂的噻吩加氢脱硫反应性能.结果表明:程序升温条件下的局部规整反应可提高催化剂的比表面积,且制备的碳化钼催化剂具有较高的噻吩加氢脱硫反应活性,在体积分数为5%的噻吩/环己烷溶液中,反应压力为3.0MPa,空速为6h-1,H2/原料液体积比500∶1的反应条件下,370℃时的噻吩转化率达到98%以上,明显高于相应的硫化钼催化剂.还原碳化终温的提高,导致碳化钼催化剂比表面积的减少和表面积炭的增多,进而使其加氢脱硫反应活性降低.MoO3在CH4/H2气氛中的还原碳化历程应为MoO3→MoO2→MoOxCy→Mo2C,实验确定的适宜还原碳化温度为675℃.
Molybdenum carbide catalysts were prepared by temperature-programmed reaction using CH4/ H2 gas mixture to carburize molybdenum trioxide at different temperatures, then were characterized with XRD and BET. TG-DTA in-situ approach was used to investigate the carburizing reaction of MoO3 in CH4/H2. The catalytic performance of molybdenum carbide catalysts was evaluated for hydrodesulfurization by using 5~ （vol） thiophene as the model reactant under the conditions of 300- 370℃, 3.0 MPa and space velocity 6 h^-1. The results indicated that molybdenum carbide catalysts possessed much higher thiophene HDS activity than MoS2, and the HDS conversion of thiophene reached 98~ at 370℃. It was also found that the BET surface area of molybdenum carbide catalysts decreased and more free carbon deposited on the catalyst surface with increasing carburizing temperature. Furthermore the HDS activity for thiophene decreased. The carburizing reaction pathway of MoO3 in CH4/H2 was MoO3→MoO2→MoOxCy→Mo2C, and the proper carburizing temperature was 675℃ as determined by experiment in this paper.
出处
《化工学报》
EI
CAS
CSCD
北大核心
2006年第4期799-804,共6页
CIESC Journal
基金
国家重点基础研究发展规划项目(G2000048003).~~
关键词
氧化钼
碳化钼
催化剂
噻吩
加氢脱硫
molybdenum trioxide
molybdenum carbide
catalyst
thiophene
hydrodesulfurization
