γ-Al2O3载体的固相法合成及Ni-Mo-P/γ-Al2O3催化剂的加氢脱硫性能

Synthesis of γ-Al_2O_3 by Solid-State Reaction and the Hydrodesulfurization Evaluation of Ni-Mo-P/γ-Al_2O_3

以硝酸铝和碳酸氢铵为原料,采用固相反应法,在低温条件下制备出γ-Al2O3的前驱体碳酸铝铵(AACH),然后挤条、焙烧,成功制备出高比表面积和大孔体积的γ-Al2O3载体。考察了原料配比、陈化温度等参数对碳酸铝铵合成的影响。采用X射线衍射、BET物理吸附、扫描电子显微镜、固体核磁共振、高分辨透射电镜等手段对AACH和γ-Al2O3载体进行了表征。以柴油中较难脱除的二苯并噻吩(DBT)为模型化合物,在高压微反装置上评价了由上述γ-Al2O3载体制备的Ni-Mo-P/γ-Al2O3催化剂的加氢脱硫活性。结果表明,最佳原料配比下,较高的陈化温度和添加PEG有利于得到结晶度较好的纯相碳酸铝铵;以其焙烧后的γ-Al2O3为载体的Ni-Mo-P/γ-Al2O3催化剂的加氢脱硫活性明显高于以传统γ-Al2O3作载体制备的催化剂。

Ammonium aluminum carbonate hydroxide （AACH） precursor of alumina （ γ-Al2O3 ） was synthesized by a low-temperature solid-state reaction with NH4HCO3 and Al（NO3）3 as reactants. Meanwhile, alumina （ γ-Al2O3 ） with high surface area and large pore volume was obtained by calcination of extruded AACH. The influences of reactants mole ratio, aging temperature on the synthesis of AACH were investigated. The synthesized AACH and alumina samples were then characterized by means of XRD, BET, SEM, 27Al MAS NMR and HRTEM. The γ-Al2O3 obtained by the calcination of extruded AACH was used as the support to prepare Ni-Mo-P/γ-Al2O3 catalyst. Then the HDS performance of Ni-Mo-P/γ-Al2O3 was evaluated in high pressure micro-reactor with dibenzothiophene （DBT） as model compound. The results demonstrated that well-crystallized AACH was prepared by the optimum mole ratio of reactants, high aging temperature and addition of PEG-400.The conversion and desulfurization of DBT over prepared Ni-Mo-P/γ-Al2O3 catalyst were obviously enhanced, compared with the catalyst supported by tradition γ-Al2O3 . 