Synthesis of a novel zeolite W and application in the catalyst for FCC gasoline hydro-upgrading

Zeolite W was synthesized via the hydrothermal crystallization method by using KOH as the potassium and alkaline source, and a kind of cheap solid silica-alumina microsphere as the unique silica and alumina sources. The effects of synthesis factors on the formation of zeolite W were systematically investigated. The corresponding CoMo/γ-Al2O3-L/W catalysts with different molar ratios of zeolite L/W were prepared for the hydro-upgrading of fluid catalytic cracking (FCC) gasoline. The as-synthesized zeolite W and catalysts were characterized by means of XRD, SEM, pyridine-FTIR, UV–vis DRS and nitrogen adsorption. When the ratio of zeolite W and L was 1:1 (Cat. 3), the catalyst exhibited the best catalytic performances for both hydrodesulfurization (HDS) and preserving research octane number (RON). The sulfur content of hydrogenated gasoline is 5.7 mg/L, and the loss of RON is only 1.22 units compared with the RON of feedstock. The catalysts containing the zeolite W and L showed the excellent performances for deep desulfurization, aromatization, isomerization and RON preservation in the hydro-upgrading process of full-range FCC gasoline. The synergy of zeolite W and zeolite L could adjust the functionality balance between the selective hydrogenation, aromatization and isomerization.