Title : Early-stage techno-environmental evaluation of a lignocellulosic biorefinery for sustainable lignin production
Abstract:
The European Commission’s Circular Economy and Bioeconomy strategies promote sustainable industrial development while reducing environmental burdens. Sustainable alternatives rely on bio-based processes which are, nowadays, at low Technology Readiness Level (TRL) for which uncertainty regarding scalability, and environmental performance at industrial scale need to be addressed. Systematic methodologies that can translate laboratory-scale experimental data into decision-support information for industrial deployment are required [1]. This work proposes an industry-oriented engineering framework to scale up and assess low TRL technologies. An emerging organosolv lignin extraction process developed by the American Society of Technology (AST) is considered as case study [2]. The methodology is based on process design followed by detailed simulation and energy integration strategies to generate complete inventory data of a process at high TRL. The evaluation is performed via ex-ante Life Cycle Assessment (LCA) and complemented by a prospective LCA to anticipate long-term environmental impacts under different future scenarios [3]. Finally a dynamic LCA accounts for potential of carbon storage and climate mitigation [4].The AST process was design upon patent and literature data and modeled in ProSimPlus® (Figure 1). This included all unit operations required to produce high-purity lignin from biomass via butanol-based organosolv fractionation [5]. Chemical composition, thermophysical properties, equipment design, and operating conditions were implemented according to chemical engineering principles. Key process indicators, including lignin and pulp yields, were validated against patent data, with deviations below 1%. Heat integration, based on pinch analysis, allowed reducing heating demand from 45.1 kW to 39.6 Environmental performance was implemented in Brightway2 and evaluated using the Environmental Footprint (EF) 3.1 method, with the production of 1 kg of lignin as functional unit. Three AST scenarios were considered: i) a simplified calculation method to scale-up the process (AST-HC) and two simulation-based variants ii) the reference process and iii) a process with solvent recovery (AST-SR). The ex-ante LCA (Figure 2) revealed that solvent (1-butanol) production dominates the GWP100 impact due to its primarily fossil-based production pathway, accounting for nearly 90% of total impact. The enhanced solvent recovery scenario (AST-SR) reduced GWP100 by 70%, despite an increase in heat demand of 40%. Prospective LCA indicated a decreasing trend in GWP100 over a 30-year horizon (2020-2050), driven by anticipated shifts from fossil-based to a bio-based solvent production pathway, and the transition of electricity production toward low-carbon generation. Dynamic LCA revealed that accounting for the timing of biogenic carbon uptake and release significantly alters the climate change results compared to static assessment. Moreover, a one-at-a-time parametric sensitivity analysis combined with Pearson correlation analysis identified the most influential engineering parameters governing system behavior and affecting the major indicators: Global Warming Potential (GWP100), lignin and pulp yields, and total heat consumption.
Overall, this study demonstrated that integrating scale-up into process engineering enables the transformation of low-TRL data into exploitable data that, combined with ex-ante and prospective LCA, facilitate an early identification of technical bottlenecks and evaluating both current and future environmental impacts that can supporting informed decision-making in the early stages of technology development [6].
