硅改性拟薄水铝石的合成及其在FCC催化剂中的应用

Synthesis of silica-modified pseudo boehmite and its application in FCC catalyst

以硅酸钠为硅源,基于双铝中和法原位合成了硅改性拟薄水铝石(Si-PB),并采用XRD、X荧光光谱、N2吸附-脱附、NH3-TPD、Py-IR等方法表征了材料的物理化学性质,并将所合成Si-PB用于FCC催化剂的制备,采用ACE装置评价了所制备催化剂的重油催化裂化反应性能。表征结果显示,所合成Si-PB具有典型的PB晶相结构;与常规PB相比,所合成Si-PB具有更高的比表面积、孔体积、表面酸密度以及微反活性,分别可达457.7 m2/g,0.81 cm3/g,438.1μmol/g,29%(w)。新鲜催化剂评价结果表明,与使用常规PB制备的催化剂(Cat-1)相比,使用Si-PB制备的催化剂(Cat-2)的油浆收率下降了2.30百分点,而汽油和总液体收率则分别增加了1.98,1.84百分点。重金属污染催化剂评价结果表明,与Cat-1相比,Cat-2的油浆收率低了1.54百分点,而汽油和总液体收率则分别高出前者1.48,0.82百分点。

Silica-modified pseudo boehmite(Si-PB)was synthesized via double-alumina neutralization method with Na4SiO4 as Si source,and characterized by XRD diffraction,X ray fluorescence spectrometry,N2 adsorption-desorption,NH3-TPD and Py-IR technique,etc.Then,FCC catalysts were prepared using Si-PB as matrix material,and evaluated the heavy oil cracking performance by ACE unit.Characterization results indicated that,the synthesized Si-PB possessed typical crystal phase of pseudo boehmite;compared with conventional pseudo boehmite(PB),the synthesized Si-PB possessed obviously higher surface area,pore volume,surface acidity density and micro reaction activity,which could reach to 457.7 m^(2)/g,0.81 cm3/g,438.1μmol/g,29%(w),respectively.ACE results for fresh catalysts suggested that,compared with catalyst based on conventional PB(Cat-1),the bottom yield of catalyst supported by Si-PB(Cat-2)decreased by 2.30 percentage point while gasoline and total liquid yields increased by 1.98,1.84 percentage point respectively;ACE results for heavy metals contaminated catalysts indicated that,compared with Cat-1,the bottom yield of Cat-2 dropped by 1.54 percentage while gasoline and total liquid yields increased by 1.48,0.82 percentage point respectively.