Ex-ante life cycle assessment of polyols using carbon captured from industrial process gas

Abstract

The steel industry needs to significantly reduce greenhouse gas (GHG) emissions as it is considered as one of the major industrial contributors to global GHG emissions. Since CO and CO₂ occur in high concentrations in steel mill gases, one of the possible options to do this is utilizing CO and CO₂ for the production of value added chemicals. With this goal, a carbon capture and utilization (CCU) technology was developed for transforming CO and CO₂ from the blast furnace gas (BFG) of a steel mill to building blocks for polyols. These polyols were then used to produce polyurethane (PUR) for the manufacturing of coatings and rigid foam for insulation boards. For assessing and comparing the life cycle environmental impacts of this novel CCU system with those of the incumbent steel and polyol system, ex-ante life cycle assessment (LCA) was carried out. Three possible scenarios of the CCU system were compared with the incumbent steel and polyol systems, assessed by performing LCAs and identifying hotspots. All three scenarios of the CCU technology showed improved environmental performance compared to the incumbent technology although limited to a maximum of about 10% reduction in carbon footprint. Energy and chemicals used to produce CCU polyols were identified as the main hotspots of the life cycle impacts of all three scenarios.