硅溶胶基质助剂的制备及反应性能研究

Study on preparation and reaction performance of silica sol matrix additive

以工业品硫酸铝溶液和水玻璃为原料,采用"一步酸化法"合成出硅溶胶,并以此硅溶胶为黏结剂,复配高岭土、ZSM-5分子筛等功能组分,制得硅基助剂。考察了制备条件对硅溶胶稳定性的影响,并利用小型提升管反应器,对硅基助剂的反应性能进行了评价。结果表明,制备硅溶胶的优选条件为:硫酸铝质量浓度(以Al2O3计)8～10 g/L,水玻璃质量浓度(以SiO2计)75～100 g/L,反应温度不高于20℃,胶体体系pH值2.5～3.0;通过向基础FCC催化剂中添加硅基助剂,可提高液化气收率,降低轻质油收率,总液收基本稳定,丙烯收率提高30%以上,丙烯选择性至少增加3个百分点,汽油辛烷值增加约1个单位。

Silica sol was prepared with commercial product water glass and aluminum sulfate as materi- als and adopting one - step acidification method. The silica- based additive was prepared using the silica sol as agglomerant and adding functionality compo- nents,such as kaolin clay and ZSM - 5 zeolite. The effects of the preparation conditions on the stability of silica sol were investigated, and the reaction per- formance of the silica- based additive were evalua- ted in a miniature riser reactor. The results showed that the optimum preparation conditions for silica sol were：the mass concentration of aluminum sulfate（ by Al2O3 ） and water glass （ by SiO2 ） 8 - 10 g/L,75 - 100 g/L respectively, the reaction temperature less than 20 ℃ , the pH value of sol system 2.5 - 3.0. Through adding the silica - based additive into the FCC catalyst,the yield of liquefied petroleum gas in- creased, the yield of light oil decreased, the yield of total liquid were steady, the yield of propylene in- creased by more than 30% ,the selectivity of propyl- ene increased by more than 3 percent poins,and the octane number of gasoline increased by about 1 unit.