噻吩类硫化物和吡啶在分子筛上竞争吸附的分子模拟

针对焦化粗苯中碱性氮化物的存在会降低催化剂的活性,给加氢脱硫过程带来不利影响的问题,采用巨正则蒙特卡罗法在温度为473.15～673.15 K下研究了不同力场下,焦化粗苯中典型的硫化物噻吩和吡啶在FAU(八面沸石)分子筛上的吸附热；在焦化粗苯加氢条件下,在温度为573.15 K、压力为0.01～ 100 MPa条件下模拟噻吩类硫化物(噻吩、2-甲基噻吩、2,5-二甲基噻吩)和吡啶在分子筛上二组分的竞争吸附；在焦化粗苯加氢条件下,焦化粗苯进料条件下,模拟噻吩类硫化物和吡啶的多组分的竞争吸附和吸附位.研究表明:在Universal力场下,计算得到的噻吩吸附热(105.50 kJ/mol)和吡啶吸附热(62.93 kJ/mol)处于文献报道的范围内；在温度为573.15 K、压力为0.01～100 MPa的条件下,各吸附质的饱和吸附量大小顺序为:噻吩＞吡啶＞2-甲基噻吩＞2,5-二甲基噻吩,2-甲基噻吩和2,5-二甲基噻吩在分子筛上的吸附量较小,噻吩和吡啶的吸附量随着压力的增大不断增大.

Molecular simulation of adsorption of thiophene-type sulfide and pyridine on FAU zeolite

Basic nitrogen compounds in crude coking benzene will decrease the activity of catalyst and bring unfavorable influence to the hydrodesulfurization process.In this dissertation,Grand Canonical Monte Carlo(GCMC) simulation method was used to investigate the adsorption heats of thiophene and pyridine on the FAU zeolite of different compass under the conditions of 473.15—673.15 K;competitive adsorption of two components between thiophene-type sulfides and pyridine on FAU at 573.15 K and 0.01—1.0MPa;under the catalytic hydrogenation condition of coking crude benzol,the competitive adsorption and competitive sites of thiophene-type sulfides and pyridine were obtained by simulation.The research results show that the adsorption heats of thiophene and pyridine are 105.50 kJ/mol and 62.93 kJ/mol respectively under universal compass,which are in the range of literature report value;under the conditions of 573.15 K and 0.01—1.0 MPa,the orders of the adsorption capacity of thiophene-type sulfides and pyridine on FAU are thiophene > pyridine >2-methylthiophene > 2,5-dimethylthiophene;thiophene and pyridine have smaller adsorption capacities than others,the adsorption capacity of the two compounds increases with the pressure increasing,and the adsorption capacity of pyridine is smaller than that of thiophene.