Influence of Partial Incineration and Optimized Acid Leaching on the Remanufacturing of Ni–Mo/γ–Al₂O₃ Catalysts

This study investigated the optimization of the remanufacturing process for spent Ni–Mo/γ-Al₂O₃ catalysts utilized in hydrodesulfurization (HDS) reactions. The proposed process encompasses essential steps, including oil washing, partial incineration, acid leaching, and complete incineration, aimed at restoring the physicochemical properties of the spent catalysts. The incorporation of partial incineration enhanced the removal of hydrocarbons and sulfur compounds, leading to notable recovery of surface area and pore volume. However, vanadium removal was insufficient with partial incineration alone, necessitating the use of an optimized acid-leaching step, where the leaching time was adjusted. The remanufactured catalysts demonstrated superior performance in HDS reactions compared to their fresh counterparts. The OPA(60)C catalyst, remanufactured through oil washing, partial incineration, 60 min of acid leaching, and complete incineration, exhibited the highest desulfurization efficiency. These findings highlight the critical role of impurity removal and the optimization of the acid-leaching duration in restoring catalyst activity. By enabling effective catalyst reuse, this process offers a sustainable and cost-effective solution for industrial applications.