Sustainable Design of Microbiorefineries from Cassava and Rejected Banana Coupled with Renewable Energy in Colombia

Abstract

Interest in decentralized small-scale biorefining has increased due to the economical, ecological, and social benefits that these alternative business models possibly bring, especially to developing countries. In this research, two microbiorefineries were conceptually designed in the context of the Colombian Caribbean region. One from cassava produces several products such as cassava starch, calcium citrate, and biogas. The other uses rejected bananas to obtain green banana flour, calcium lactate, and glucose syrup. Design rules for small-scale biorefinery processes developed by previous authors were considered and supported on simulations, literature data, local raw material costs, and equipment quotes to determine the minimum processing scale for economic feasibility (MPSEF) for each case. Aspen Plus® software was used for the simulations in tandem with MATLAB for the calculation of the MPSEF. Values of 4.2 and 22.4 t/day were found for the cassava and rejected banana biorefineries respectively. Applying the WAste Reduction algorithm (WAR), generated potential environmental impacts (PEI) values of -13.1 and -9.4 PEI/h for cassava and rejected banana were obtained, suggesting that these process topologies have an environmentally friendly performance. In addition, an economic evaluation of an energy supply system assisted by solar energy was carried out, based on a non-linear programming optimization model solved with LINGO® software, finding that economic performance in terms of IRR is reduced by 24.9% when solar collectors provide 60% of the energy requirements.