焦化柴油中二苯并噻吩类含硫化合物的加氢脱硫反应动力学

Kinetics of DBTs Hydrodesulfurization in a Coker Diesel

采用20mL高压连续反应装置,在压力5.0MPa、体积空速0.7～3.0h-1、氢/油体积比400、温度330℃的条件下,考察了焦化柴油中难脱除的二苯并噻吩类含硫化合物(DBTs)在工业化负载型NiMo/γ-Al2O3催化剂上的加氢脱硫(HDS)反应活性。采用气相色谱-脉冲火焰光度检测器(GC-PFPD)对加氢前后焦化柴油中含硫化合物进行了定量分析,研究了它们在深度HDS过程中的脱除规律,建立了难脱除DBTs的HDS反应一级动力学模型。焦化柴油的深度HDS过程中,DBTs尤其是4位和6位取代的DBTs是最难脱除的含硫化合物,各含硫化合物的HDS反应速率常数大小顺序为DBT、4-MDBT、4-EDBT、3,6-DMDBT、4-E,6-MDBT、2,4,6-TMDBT、4,6-DMDBT。

The reactivity of the refractory sulfur compounds,i.e.dibenzothiophenes（DBTs） was investigated by hydrotreating a coker diesel with a commercial NiMo/γ-Al2O3 catalyst under commercial operation conditions of total pressure 5.0 MPa,liquid hourly space velocity 0.7-3.0 h-1,gas-to-liquid volume ratio 400 and temperature 330℃ in a 20 mL high-pressure reaction unit.Gas chromatography-pulsed flame photometric detector（GC-PFPD） was used to analyze sulfur compounds in the feed and the hydrodesulfurization（HDS） products.The kinetic model of first-order reaction of individual DBTs was built and the removal behaviors of various sulfur compounds in deep HDS process were studied.The results showed that DBT and its alkyl-derivatives,especially the DBTs with substituents at 4 position and 6 position,were the most refractory sulfur compounds.The order of the apparent reaction rate constant of individual sulfur compounds from high to low was DBT,4-MDBT,4-EDBT,3,6-DMDBT,4-E,6-MDBT,2,4,6-TMDBT,4,6-DMDBT.