Integrated process design, techno-economic and environmental analysis of chokeberry pomace biorefineries: Phenolic compounds extraction with ethanol or energy production?

Abstract

Learning how to transform by-products or waste from the food industry instead of sending them directly to landfill is key to reducing food waste and obtaining new value-added products from them. This study carries out the environmental and economic assessment of the valorisation of chokeberry pomace for the extraction of phenolic compounds in a multi-product and circular biorefinery. For this purpose, two scenarios were analysed: scenario A, the remaining part of the pomace is used to obtain bioethanol and a lignin-rich stream; and scenario B, it is used for bioenergy production. The Life Cycle Assessment methodology is used to determine the environmental critical points, following a cradle-to-gate approach and considering impact categories such as Global Warming, Freshwater Eutrophication or Fossil Resource Scarcity, among others. The results show that scenario B performs better in all the impact categories analysed compared to scenario A. In both cases the main hotspot is the generation of the steam needed in the biorefinery, followed by the emissions in the agricultural stage and the demand for chemicals in the plant. Furthermore, this document presents a techno-economic analysis to assess the economic feasibility of both scenarios and a sensitivity analysis to determine the profitability factors of the platform, considering the total capital investment, operating costs and indicators such as Net Present Value or Internal Rate of Return. The results show that the scenario analysed is not profitable at any of the scales studied, requiring to optimise the production yield or a reduction in the plant's operating costs.