Evaluating pretreatment process impacts in a multi-product wheat straw biorefinery using prospective life cycle assessment

Abstract

Wheat straw holds significant potential as a renewable resource for a sustainable bioeconomy; however, its complex structure necessitates pretreatment to enable efficient conversion into high-value products. In this study, we investigate four different pretreatment cases to deconstruct the complex structure of wheat straw. Case 1 considers the liquid hot water (LHW) pretreatment method; Case 2, the dilute acid (DA) pretreatment approach; Case 3, the ammonia fiber expansion (AFX); and Case 4, the organosolv (OS) pretreatment method. Each case is designed to preferentially target one of the major biomass components cellulose, hemicellulose, or lignin to enhance the overall efficiency of downstream conversion processes. To assess environmental impacts, we apply prospective life cycle assessment using Activity Browser (AB), an open-source platform designed to perform LCA under evolving future conditions. In this study, we use the open-source BioSTEAM framework for modeling the foreground system. Future background systems are based on regional model of investments and development (REMIND) energy scenarios aligned with the Paris agreement, covering milestone years 2030, 2040, 2050, and beyond. Results show significant reductions in global warming potential when shifting from REMIND-SSP2-Base to REMIND-SSP2-Pkbudg500 in 2030: LHW (59%), DA (54%), AFX (26%), and OS (44%). For 2050, reductions are LHW (43%), DA (35%), AFX (12%), and OS (28%). The goal of this study is to address the gap in understanding how pretreatment processes can be effectively scaled up, with the aim of enhancing the sustainability of emerging processes and materials.