A techno-economically feasible and sustainable C-lignin biorefinery

Abstract

C-lignin, a homo-biopolymer, has great potential as a feedstock for biorefineries that convert it into high value-added products, for example, catechol as a precursor of pharmaceuticals. In this study, we conducted a techno-economic analysis (TEA) and life cycle assessment (LCA) of a conceptual biorefinery where waste castor seed coats are converted into high value-added products, including pulp, catechol, oligomers, and propylene. After several rounds of optimization through scenario studies, with the incorporation of combined heat and power (CHP) and pressure swing adsorption (PSA) systems, as well as importing heat and electricity instead of using natural gas, bio-catechol achieves a minimum selling price (MSP) of $2.02 per kg, 23% lower than the market price, and a carbon footprint of 1.58 kg CO₂ eq. per kg, 72% lower than that of fossil derived catechol. In addition, the use of district heat co-generated by natural gas or biogas CHP plants can further reduce the GWP of bio-catechol, but with trade-offs in other environmental impacts. Nevertheless, this study has proposed potentially economically viable and sustainable C-lignin biorefineries with products to replace fossil derived catechol.