Lignin fractionation from laboratory to commercialization: chemistry, scalability and techno-economic analysis

Fractionation represents a promising methodology to refine technical lignin and facilitate lignin valorization. Many lignin fractionation processes have been developed on a laboratory scale, but none have been implemented on a commercial scale. The current publicly available technical and financial performance analyses regarding industrial-scale lignin fractionation are insufficient to justify its feasibility. Herein, we report our detailed techno-economic analysis to provide knowledge and insights into industrial-scale lignin fractionation. Laboratory-scale experiments were performed to collect inputs for process simulation. The solvents were selected based on lignin solubility, potential for commercialization and environmental impacts. Fractionated lignins were thoroughly characterized and their properties exhibited good correlation with molecular weight. The economic analysis revealed that the capital expenditures for a co-located lignin fractionation facility ranged from 20 to 32 million USD, with an operational expenditure between 390 and 460 USD per t. The major operational cost drivers were determined to be raw lignin, solvent make-up, and depreciation. The minimum product selling prices for the low molecular weight fraction were estimated to be between 700 and 1000 USD per t, assuming the high molecular weight fraction has the same value as raw lignin. Sensitivity analysis indicated that the facility scale, the solvent losses, and the raw lignin cost have major impacts on capital expenditures and operational expenditures.