Environmental and Preliminary Economic Assessment of Integrated Resource Recovery from Spent Fluid Catalytic Cracking Catalysts

Abstract

Abstract This study evaluates an integrated resource-recovery route for spent fluid catalytic cracking (FCC) catalysts, consisting of alkaline roasting, water leaching, adsorption/desorption, precipitation recovery, and leaching-residue valorization. Using the treatment of 1 t of spent FCC catalyst as the functional unit, environmental impacts were assessed in SimaPro 10.1 using Environmental Footprint 3.1 (adapted) as the primary life-cycle impact assessment method, complemented by an operating-level cost assessment, sensitivity analysis, and scenario analysis. Before product-substitution credits, the climate-change impacts of the wet-recovery and leaching-residue-valorization stages were 1,536.56 and 1,940.11 kg CO2-eq, respectively. After system expansion, all 16 main impact categories showed net environmental benefits under the adopted substitution assumptions; when the two freshwater-ecotoxicity subindicators are included, all 18 displayed results were also net negative. The net climate-change impact was – 2,257.14 kg CO2-eq, while resource use for minerals and metals and fossil resources showed net reductions of 0.817 kg Sb-eq and 37,306.47 MJ, respectively. The estimated operating cost was 5,763.35 Chinese yuan (CNY) per t of spent catalyst, while the potential product revenue was 53,254.45 CNY/t under the adopted market-price assumptions. These results indicate favorable operating-level economic potential but should not be interpreted as evidence of industrial profitability. Electricity consumption is the dominant driver of energy- and atmosphere-related impacts, whereas CuSO4·5H2O and ammonium-containing reagents are important contributors to several toxicity- and eutrophication-related impacts. The results therefore support a coordinated optimization strategy combining energy-efficiency improvement, low-carbon electricity, and reduction or substitution of high-impact reagents.