拟薄水铝石@高岭土复合材料的合成及其在FCC催化剂中的应用

Synthesis of pseudo-boehmite@kaolinite composite and its application in FCC catalyst

以酸抽提高岭土生成的铝物种为酸性铝源、偏铝酸钠为外加碱性铝源,采用双铝中和法在高岭土结构中原位构筑了拟薄水铝石结构单元,合成了拟薄水铝石@高岭土复合材料,将所合成复合材料用于催化裂化催化剂的制备,考察了所制备催化剂的重油催化裂化反应性能,采用XRD、N2吸附-脱附、氨气程序升温脱附、Py-FTIR等方法表征了所制备材料的物理化学性质。表征结果显示,拟薄水铝石结构单元被成功地引入到高岭土结构中,与常规高岭土相比,所制备的拟薄水铝石@高岭土复合材料具有更高的比表面积、孔体积和表面酸密度。实验结果表明,与使用常规高岭土制备的催化剂相比,使用拟薄水铝石@高岭土复合材料制备的催化剂的重油收率降低了1.50百分点,转化率提高2.85百分点,同时汽油收率和总液收率分别提高1.54和1.02百分点。

A pseudo-boehmite constitutional unit was constructed insitu in kaolinite structure through double-alumina neutralization method,with Al species derived from acid extraction of kaolinite as acidic Al source and NaAlO2 as alkaline Al source,respectively,thus a pseudo-boehmite@kaolinite composite(PB@kaolinite)was synthesized.The performance of the composite,as catalytic cracking catalyst,in catalytic cracking process of heavy oil was investigated.XRD,N2 adsorption-desorption,NH3-TPD and pyridine-adsorption FTIR were employed to characterize physicochemical properties of PB@kaolinite.The characterization results indicated that compared with ordinary kaolinite,the PB@kaolinite,with pseudo-boehmite constitutional unit being successfully introduced in the kaolinite structure,possessed much higher specific surface area,pore volume,and acid site density on surface.Evaluation results suggested that,compared with using catalyst prepared with ordinary kaolinite,by using catalyst prepared with PB@kaolinite,the heavy oil yield decreased by 1.50 percentage points,the conversion,gasoline yield and total liquid yield increased by 2.85 percentage points,1.54 percentage points and 1.02 percentage points respectively.