Pt-Pd/SiO2-Al2O3催化剂芳烃加氢饱和性能研究

以SiO2质量分数40%的无定形硅铝和氢氧化铝干胶为主要原料，制备不同SiO₂含量的SiO₂-Al₂O₃载体，以氯铂酸和氯化钯为Pt和Pd的前躯物配制浸渍液，并用等体积浸渍法制备Pt-Pd/SiO₂-Al₂O₃催化剂。采用N₂吸附-脱附、X射线衍射、程序升温脱附、金相显微镜、透射电子显微镜等手段对所制备催化剂进行表征，在10 mL固定床加氢装置上，以2%（w）四氢萘+10%（w）十氢萘+88%（w）异辛烷混合物为原料对催化剂进行芳烃加氢活性评价。结果表明：在SiO₂质量分数为20%~40%范围内，随着SiO₂含量的增加，催化剂的比表面积增大，晶相组成不变，中强酸酸量增加，L酸酸量减少，B酸酸量增加；Pt-Pd在SiO₂-Al₂O₃载体上的分散由蛋壳型转变为均匀型，分散度增加；其催化四氢萘加氢的活性提高。随着浸渍液中盐酸浓度增加，催化剂上活性组分的分散度先增大后减小，盐酸浓度为0.1 mol/L时Pt-Pd/SiO₂-Al₂O₃活性组分的分散度最好，催化剂的四氢萘加氢活性最高。

STUDY ON AROMATICS HYDROGENATION SATURATION PERFORMANCE OF Pt-Pd/SiO2-Al2O3 CATALYST

TheSiO₂-Al₂O₃ carriers with different SiO₂ contents were prepared by using the amorphous aluminosilicate with mass fraction of 40% SiO₂ and aluminum hydroxide gel as raw materials, and Pt-Pd/SiO₂-Al₂O₃ catalysts were prepared by equal volume impregnation method with chloroplatinic acid and palladium chloride as precursors of Pt and Pd. The prepared catalyst was characterized by N₂ adsorption-desorption, XRD, TPD, metallographic microscope, TEM and other methods. On a 10 mL fixed bed hydrogenation unit, the hydrogenation activity of the catalyst was evaluated with the model compound containing 2% tetralin + 10% decalin + 88% isooctane as the raw material. The results showed that the specific surface of the catalysts increased with the increase of SiO₂ content in the range of 20%-40%, the crystal phase composition remained unchanged, the amount of B acid and medium acid increased but L acid declined.The dispersion of Pt-Pd on SiO₂-Al₂O₃ carriers was gradually changed from eggshell type to homogeneous type,the degree of dispersion increased, and the hydrogenation activity of tetralin increased. With the increase of the concentration of hydrochloric acid in the impregnation solution, the dispersion of the catalyst first increased and then decreased. The Pt-Pd/SiO₂-Al₂O₃active component had the best dispersion at the concentration of 0.1 mol/L hydrochloric acid, and the tetralin hydrogenation activity of the catalyst was the highest.