Process Design and Techno-Economic Assessment of Apple Pomace Valorization for Pectin, Phenolic Extracts, and Biochar Production

Abstract

Apple pomace is a major agro-industrial waste stream, driving resource inefficiency and environmental pollution. Sustainable valorization of this residue is essential to reducing food waste, mitigating environmental impacts, and advancing the circular bioeconomy. Here, we propose an integrated multiproduct biorefinery combining the sequential extraction of phenolic compounds and pectin with subsequent biochar production. An integrated process design followed by a techno-economic assessment was performed under two scenarios: a base case processing 11,900 tons of pomace per year and a 5-fold scale-up. The biorefinery achieved annual outputs of 1635 tons of pectin, 595 tons of biochar, and 29,784 m3 of phenolic-rich extract. The scaled-up scenario showed superior economic performance with a net present value of USD 115.85 million, highlighting how economies of scale can support the deployment of circular biorefineries. Scenario I had a manufacturing cost of USD 33.55 million, while scenario II reached USD 160.80 million due to scale-up. However, annual revenues were USD 38.08 million and USD 190.42 million for scenarios I and II, respectively, with return on investment (ROI) increasing from 25.05 to 43.35% and cumulative cash ratio from 5.76 to 9.77. The discounted payback period (DPBP) improved from 4.14 years to 2.85 years, and the modified internal rate of return (mIRR) rose from 14.70 to 17.68%, reflecting enhanced financial resilience and long-term stability. Sensitivity analysis identified pectin market stability and ethanol costs as key determinants of the economic resilience. Sustainability performance was quantified using the Path2Green metric, indicating a strong compliance with green extraction principles. These findings support integrated apple pomace valorization for viable and environmentally beneficial biorefineries.