Synthesis of ordered hierarchically porous L-SBA-15 material and its hydro-upgrading performance for FCC gasoline

Abstract

A micro/mesoporous composite L-SBA-15 (LS) material was successfully in situ synthesized using low-cost solid silica–alumina microspheres by a two-step hydrothermal crystallization method, and the as-synthesized material was used as support additive to prepare the hydro-upgrading catalyst for fluid catalytic cracking (FCC) gasoline. LS and the corresponding catalyst CoMo/LS-γ-Al2O3(CoMo/LSA) were characterized by means of XRD, SEM, TEM, nitrogen adsorption, 27Al MAS NMR and Py-FTIR. The physicochemical properties of the CoMo/LSA were compared with those of CoMo/Al2O3 catalyst and the ones incorporated with other different support additives such as zeolite L, SBA-15 and Al-SBA-15. The characterization results demonstrated that LS possessed the typical characteristics of mesoporous silica SBA-15 and microporous zeolite L. The textural properties of the composite material were dramatically improved and the results of acidity measurements indicated that LS exhibited a high acid amount and an appropriate Brönsted and Lewis acid distribution. The catalyst CoMo/LSA showed superior hydro-upgrading catalytic performances, i.e., excellent hydrodesulfurization (HDS), hydroisomerization, aromatization activities and a good preserving ability of the octane number, which can be attributed to the hierarchically porous structure and the properly acidic properties of LS. Thus, LS has potential application for clean gasoline upgrading.