Techno-economic feasibility of a recycling plant for the extraction of metals and boehmite from hazardous petroleum spent catalysts

Petroleum spent hydroprocessing catalysts are hazardous solid waste, the efficient recycling of which is a serious challenge to refineries. However, information on the economic feasibility of spent catalysts recycling plants is scarce, which is critical for environmental authorities and decision-makers. In this work, an innovative recycling scheme targeting hydrometallurgical recovery of base metals (Ni, Mo, and V) and transforming low-value Al residue into a high-value boehmite (γ-AlOOH) as the key product was considered an efficient way to beneficiate the hazardous spent hydroprocessing catalysts. A preliminary techno-economic evaluation of such a recycling scheme was performed to assess the feasibility of the proposed recycling scheme. The recovery cost (valuable metals and boehmite) and potential revenue were estimated to study the economics of the process. The preliminary results have suggested that the recycling scheme is economically feasible with a high internal rate of return (IRR) of 12.3%, a net present value of 38.6 million USD, and a short payback period of 8.7 years. Furthermore, a sensitivity analysis (± 10%) conducted on key parameters showed that the selling prices of the finished products and the cost of chemicals were the most important factors affecting plant economics. Overall, the recycling scheme was sustainable and avoided landfilling of spent catalysts as the residue can be beneficiated into a high-value product. The results from the economic feasibility study are likely to assist the stakeholders and decision-makers in making investment and policy decisions for the valorization of spent hydroprocessing catalysts.