Ti-Mg-Al复合氧化物催化材料的制备及其加氢脱硫性能

Preparation and hydrodesulfurization performance of Ti-Mg-Al composite oxides

关键词:  pH值摆动法  并流沉淀法  Ti-Mg-Al 三元复合物  选择性加氢脱硫 

Key words:  pH swing method  paralleled flow precipitation method  trinary Ti-Mg-Al composite oxides  selective hydrodesulfurization

摘要:

采用pH值摆动法、并流沉淀法制备了Al₂O₃、TiO₂-Al₂O₃二元复合物、TiO₂-MgO-Al₂O₃ 和MgO-TiO₂-Al₂O₃三元复合物,并对以其为载体的催化剂进行了催化裂化重汽油加氢脱硫反应性能评价。结果 表明,在所制备的TiO₂-Al₂O₃二元复合载体中,TiO₂分散在Al₂O₃表面上,且随其含量的增加TiO₂逐渐在Al₂O₃表面上富集；与TiO₂-Al₂O₃二元复合载体相比,三元复合载体的总孔容和平均孔径减小,但是总酸量增加。相比较而言,TiO₂-MgO-Al₂O₃三元复合载体基催化剂对催化裂化重汽油的脱硫率优于TiO₂-Al₂O₃二元复合载体基催化剂,脱硫率在90%以上,且前者的烯烃饱和率也较低,表明该催化剂具有良好的加氢脱硫选择性。

Abstract:

A series of Al₂O₃, TiO₂-Al₂O₃ and TiO₂-MgO-Al₂O₃ oxides were prepared by the pH swing method and the paralleled flow precipitation method, respectively, and their supported hydrodesulfurization catalysts for the hydro-upgrading of heavy fluid catalytic cracking naphtha were assessed. The characterization results showed that in the binary TiO₂-Al₂O₃ supports, TiO₂ is dispersed on the surface of Al₂O₃ and there is a surface enriching tendency of TiO₂ with the increasing TiO₂ content; compared with binary TiO₂-Al₂O₃ supports, trinary TiO₂-MgO-Al₂O₃ supports have relatively smaller pore volumes and diameters but higher acid amounts. The catalytic assessment results revealed that the catalysts supported on trinary TiO₂-MgO-Al₂O₃ oxides demonstrated better hydrosulfurization performance,and gave a desulfurization ratio of >90% while presenting a lower olefin saturation.