Sustainable production of ethyl levulinate by levulinic acid esterification obtained from Colombian rice straw

Abstract

E-fuels are synthetic fuels produced from renewable sources that have garnered attention because of their potential to reduce environmental impacts in the transport sector. Ethyl levulinate is a fuel additive that can address issues associated with traditional fuels. This product can be obtained from agro-industrial wastes such as rice straw. Therefore, the aim of this study was to assess the technical, economic, and environmental feasibility of producing ethyl levulinate from Colombian rice straw. Aspen Plus v12 and life cycle assessment methodology were used for evaluating the process through the cultivation to the biorefinery stage. A base scenario was analyzed, with an overall yield of 0.115 kg ethyl levulinate/kg rice straw and a total energy consumption of 133.2 kWh/kg of ethyl levulinate produced. A carbon footprint of 2.71 kg CO2-eq/kg Ethyl levulinate was observed, which primarily ascribed to the use of steam derived from fossil fuels. An alternative scenario was proposed by implementing two changes to reduce the environmental impacts. First, steam was generated by the solid hydrolyzed residue combustion, and second, the paddy rice yield was increased to 5.7 t/ha. Reductions of 58.5% and 25.4% in the carbon footprint and ozone depletion were respectively obtained from these improvements. A class V economic assessment is performed for the alternative scenario, yielding a net present value of 18.7 MUSD, payback period of 5 years, and return on investment of 19.6%. Hence, the production of Ethyl levulinate from rice straw is a feasible alternative to boost the e-fuel market while upgrading agro-industrial waste into valuable products.