Catalysts based on zeolite ZSM-23 for isodewaxing of a lubricant stock

Granular Pt/(ZSM-23-γ-Al₂O₃) catalysts with different platinum and zeolite contents have been synthesized with the aim of developing efficient isodewaxing catalysts for lowering the pour point of lubricants and diesel fuels. Their physicochemical properties have been studied by X-ray diffraction, temperature-programmed desorption of ammonia, and low-temperature nitrogen adsorption/desorption. The effects of catalyst composition and process conditions (1.0–3.0 MPa, 220–400°C) on the outcomes of the isodewaxing of the 280°C-EBP lubricant fraction isolated from the hydrocracking product of vacuum gas oil have been investigated. The highest yields of products with the same pour points have been obtained with a 0.30 wt % platinum catalyst supported on the 20 wt % zeolite ZSM-23 + 80 wt % γ-Al₂O₃ material. An analysis of the basic performance characteristics of the isodewaxing catalysts based on zeolite ZSM-23 and dewaxing catalysts based on zeolite ZSM-5 has demonstrated that the catalysts based on ZSM-23 ensure higher yields of dew-axed products than the laboratory and commercial catalysts based on ZSM-5.