中微双孔分子筛Beta-MCM-41的微波合成及加氢脱硫性能研究

以四乙基氢氧化铵(TEAOH)为微孔模板剂,十六烷基三甲基溴化铵(CTAB)为介孔模板剂,SiO2、Fumed Silica或TEOS为硅源,通过微波两步自组装合成Beta-MCM-41型中微双孔分子筛。然后以合成的Beta-MCM-41(BM-S-M)、实验室自制的Beta、MCM-41、SBA-15以及γ-Al2O3为载体,通过等体积浸渍15%MoO3,3%NiO和3%CoO,制备得到Co-Mo-Ni-BM-S-M等氧化物催化剂;并在间歇式高温高压反应釜中,在350℃、5.0MPa H2压力下,以二苯并噻吩(DBT)为模拟油品研究所制备催化剂的加氢脱硫性能及反应动力学。结果表明,SiO2为硅源,微波辐射合成的BM-S-M分子筛结构有序性更好,比表面积(1033.923m2/g)和孔容(0.729cm3/g)更大,孔径集中分布在3.08nm(中孔)和1.22nm(微孔),且具有较强的酸性中心。4种不同载体催化剂的DBT加氢脱硫活性顺序为Co-Mo-Ni-BM-S-M>Co-Mo-Ni-MCM-41>商业Co-Mo-Al2O3>Co-Mo-Ni-Beta。此外,4种不同载体催化剂的加氢脱硫过程符合拟一级动力学规律。

MICROMAVE-ACCELERATED SYNTHESIS OF MICRO-MESOPOROUS MOLECULAR SIEVE BETA-MCM-41AND ITS HYDRODESULFURIZATION (HDS) PROPERTIES

A new micro-mesoporous molecular sieve Beta-MCM-41 was synthesized in two steps via the self-assembly of zeolite nanoparticles under microwave radiation.SiO2,Fumed Silica or TEOS as silica sources,and separately using tetraethylammoniumhydroxide(TEAOH) and cetyltrimethylammoniumbromide(CTAB) as the template of Beta building units,and the template of MCM-41 building units.A series of catalysts were prepared by respectively loading 15% MoO3,3% CoO and 3% NiO on the lab-prepared Beta,MCM-41 and BM-S-M via isopyknic impregnation,and then their HDS properties were investigated by using the dibenzothiophene(DBT) as a substitute for real fuels in the high pressure heating reaction still under 350℃ and 5.0MPa.The results indicated that the micro-mesoporous molecular sieve Beta-MCM-41 had large surface area and large pore volume,coupled with the uniform pore diameter(3.08nm mesopore and 1.22nm micropore).The reaction kinetics study showed that the catalytic activity of the four catalysts in the following order: Co-Mo-Ni-BM-S-M> Co-Mo-Ni-MCM-41>commercial Co-Mo-Al2O3>Co-Mo-Ni-Beta.The HDS reactions catalyzed by the four catalysts were all pseudo-first-order dynamic reactions.