A life cycle assessment model to evaluate the environmental sustainability of lignin-based polyols

Abstract

Lignin-based polyols are expected to provide significant environmental benefits by offering new synthetic routes to various types of bio-resins for coating applications. Currently, no models evaluating lignin-based polyols are available in the literature, therefore, the present study introduces a new model to assess environmental impacts associated with the synthesis of lignin-based polyols and to evaluate their potential environmental advantages in bio-product manufacturing. The model follows the life cycle assessment methodology and is based on lignin-based polyols production at a pilot scale, beginning with kraft lignin extraction, followed by solvent fractionation. The results indicate that, compared to their petrochemical counterparts, lignin-based polyols demonstrate superior environmental performance under specific conditions, such as the use of bio-based solvents and an appropriate energy mix. Tetrahydrofuran and electricity consumption emerge as the primary hotspots contributing to environmental impact categories such as climate change, fossil resource use, and water use—identified as the main contributors to the overall environmental impact of lignin-based polyol production. An uncertainty analysis was conducted using Monte Carlo simulation. Based on the findings, producers can consider lignin-based polyols as a promising raw material if they replace tetrahydrofuran with its bio-based counterpart and adopt a renewable energy mix for production. This model can be easily extended by researchers and/or practitioners to further evaluate the environmental impacts of bio-products derived from lignin-based polyols. Moreover, the results of this study can guide policymakers in shaping bio-product policies, as lignin-based polyols show promise as a more sustainable chemical alternative.