以高岭土为硅源的含硅拟薄水铝石的制备及表征

PREPARATION AND CHARACTERIZATION OF SILICON-CONTAINING PSEUDO-BOEHMITE

以高岭土为硅源制备含硅拟薄水铝石,应用正交设计试验考察偏铝酸钠浓度、硫酸铝浓度、反应温度以及pH对含硅拟薄水铝石性质的影响,采用XRD,BET,FT-IR,SEM对样品进行表征,并将样品制备成催化剂,进行渣油加氢活性评价。结果表明,采用本方法制备的含硅拟薄水铝石成本低廉、制备流程简单,含硅氧化铝孔体积可达0.866cm3/g,大孔比例(孔径大于20nm的大孔所占比例)达到52.63%,颗粒直径最大为54.14μm,B/L酸比值相对于碳化法和硫酸铝法制备的含硅氧化铝分别提高6.2%和3.5%,同时,制备的催化剂具有良好的加氢性能,在保证脱杂质率与其它两种方法相当的情况下,大于500℃渣油的转化率比碳化法和硫酸铝法分别提高14.5%和11.6%。

Silicon-containing pseudo-boehmites were prepared with kaolin as silicon source and then used to prepare the related catalysts. Orthogonal design experiments were applied to investigate the effect of the concentration of sodium meta-aluminate and aluminum sulfate, reaction temperature, pH on the characteristics of the silicon-containing pseudo-boehmite and catalysts. The samples were characterized by XRD, BET, FT-IR, and SEM. The evaluation tests of residual hydrogenation activity were conducted. The results show that the silicon-containing pseudo-boehmites are easily prepared with lower cost. The pore volume of silicon-containing alumina is 0. 866 cm^3/g, and the proportion of large pore （pore diameter more than 20 nm） can reach 52.63%. The particle diameter can reach maximum 54.14 μm. Compared with the silicon-containing alumina prepared by carbonation method and aluminum sulfate method, the B/L acid value of the support by new method is higher by 6.3% and 3.5 %, respectively. The catalyst prepared by the new method has a good hydrogenation performance. At the similar removal rate of impurities, the conversion of residue above 500 ℃ is 14.5% and 11.6%, respectively higher than that prepared by the carbonation method and aluminum sulfate method.