Preparation, Characterization And Catalytic Application Of Hierarchically Porous Alumina

γ-Alumina is always used as support of hydrotreating process. Modifying the structure or surface property of supports is one of approaches to innovation of the catalyst. In this paper, the synthesis conditions were systematically investigated to optimize the structure of alumina. The evaluation of catalytic property of alumina in hydrodesulfurization process was carried out in micro reaction device. The relationship between the structure of the catalysts and its desulfurization property was also investigated.In the presence of the sucrose and polyethylene glycol, mesoporous alumina was synthesized via hydrothermal method using ammonia and ammonium carbonate as precipitator respectively. The effect of synthesis factors such as pH value, crystallization temperature, the aging time, etc on the structure of alumina was systematically investigated. The results showed that the alumina structure could be controlled by tuning the synthesis factors. The samples prepared with ammonia as precipitator exhibits larger surface area, larger pore size and pore volume. The products areγ-alumina with high relative crystallinity.Of pity is these samples bear broaden pore distribution.The investigation showed that the structure of alumina prepared with ammonium carbonate as precipitator is strongly influenced by pH value and concentration of precipitator. The sample with bimodal pore size distribution can be obtained when pH value of synthesis system is up to 10. Alumina with larger pore size and pore volume can be synthesized at high concentration of precipitator. Also, the sample with bimodal pore structure can be showed in the condition of the longer aging time and introduction of anti-addition method.The performance of the catalysts for hydrodesulfurization were evaluated in high pressure micro-reactor using 4,6-DMDBT as model compound. The results showed that the catalyst prepared with synthesis alumina as support demonstrates high catalytic activity . The maximum conversion and desulfurization ratio of 4,6-DMDBT can be all up to 99.4%. The investigation showed that the main factors to effect the reaction properties are reduced amount of Mo species and pore distribution of the catalyst, The catalysts prepared with synthesis alumina as support bear much more reduced amount of Mo compared with the catalyst prepared. The more amount of pore with diameter between 7 and 10 nm the catalyst has, the higher the conversion and desulfurization ratio are.