Techno-economicAssessment of the Industrial-ScaleProduction of Epoxidized Kraft Lignin for Adhesives or Coatings

Lignin is an abundantly available biopolymer and as such has an emerging potential for utilization in value-added applications. The designed industrial-scale process utilizes equipment that is currently in use on an industrial scale, which favors the scale-up of the process. A novel process model in Aspen Plus provides the mass and energy balances of the production process. The main processing steps are lignin solution preparation, epoxidation reaction, solvent separation, solvent recycling, and product recovery. The production process itself produces a negligible amount of waste and has no greenhouse gas emissions. The greenhouse gas emissions of utility production depend on the energy source and fall close to zero if green energy is used. The recycling rates of the unreacted solvents are over 99%, and it is possible to use biobased solvents in the process. Efficient solvent recycling is a key parameter for the profitability of the process. The minimum selling price of epoxidized kraft lignin was estimated as 0.68 €/kg when produced in a plant integrated with an existing pulp mill or biorefinery. This research shows that the epoxidized kraft lignin production process is technically and economically feasible in the current adhesive and coatings markets.