A Comprehensive Life Cycle Assessment of Sustainable Novel Co-Production of Surfactant and Fuel from Industrial Flue Gas Via Fischer-Tropsch Synthesis

Abstract

This study conducts a life cycle assessment (LCA) of a novel CO2 utilization system for co-producing alcohol ethoxylate (AE7), a high-value surfactant, and liquid fuel from industrial flue gas. Traditional AE7 production relies on fossil and minor bio-based resources, but this research uses CO2 from paper and steel industry emissions, filling a critical research gap. Fischer-Tropsch (FT) synthesis, driven by CO2 and H2 reactions, produces C11-C13 alkanes and light-to-medium fuels. These alkanes are converted into C12-C14 fatty alcohols for AE7 production. Yields (w/w) of AE7 and fuel are 3.7% and 3.4% for paper flue gas, and 8.0% and 9.5% for steel flue gas. Hydrogen and electricity require 13.4 and 33.3 kWh supplied by wind power per kg flue gas, respectively. Life cycle impacts, including global warming potential (GWP), are evaluated using ReCiPe, Impact+, and Product Environmental Footprint (PEF) methods. Compared to conventional systems (GWP 2.2–3.6 kg CO2e/kg AE), the new system achieves a lower GWP (0.4–1.3 kg CO2e/kg flue gas) in cradle-to-gate terms. Paper flue gas, containing biogenic CO2, achieves further GWP reductions, yielding a total GWP of 2.68 kg CO2e for paper and 10.28 kg CO2e for steel flue gas (cradle-to-grave). This demonstrates that biogenic CO2 utilization is key for sustainably producing surfactants and fuel.

Keywords: CCUS, carbon dioxide reuse, carbon dioxide utilization, LCA, surfactant, CO2 biorefinery, product environmental footprint