Techno-economic assessment for the large-scale production of colloidal lignin particles

Abstract

The purpose of this study is to investigate the techno-economic feasibility of an environmentally sustainable and green process for the cost-effective large-scale manufacturing of colloidal lignin particles. The process involves the instantaneous formation of colloidal lignin particles (CLPs) through self-assembly when a concentrated solution of lignin in tetrahydrofuran (THF) and ethanol is introduced into water. The capacity of the plant is assumed to be 50 kt per year of dry colloidal lignin and Aspen plus simulation program is used for the mass and energy balance calculations. The process equipment design and pricing are carried out based on relevant literature and vendor data. Results show that the total investment cost for a plant integrated with an existing pulp mill or bio-refinery is 36 M€ and the annual operating cost is 46 M€. The project lifetime is assumed as 20 years and the cost of production of colloidal lignin is found to be 0.99 € kg⁻¹ (in case of integration) and 1.59 € kg⁻¹ (without integration). The revenue for the process comes mainly from selling the colloidal lignin particles and additional revenue is generated from high pressure and low-pressure steam condensate sold as district heat. The payback period with a CLP selling price of 1.10 € kg⁻¹ is found to be roughly 5 years. A minimum profitability requirement of 10% is considered for the techno-economic analysis and the internal rate of return (IRR) is calculated as 17% making the process viable and profitable. In addition, a sensitivity analysis is carried out to evaluate the effect of raw material price and ethanol recovery on the operating cost. Colloidal lignin has the potential to compete favorably as a renewable replacement for petroleum based feedstock like polyethylene, polypropylene, polyethylene terephthalate (PET) and phenol and can be used in attractive applications like phenol formaldehyde (PF) resins, foams, carbon fillers, bactericides and composites.