Life Cycle Environmental Implications of Ionic-Liquid-Based Carbon Capture and Storage Processes and Its Alternative Improvement Cases

As a new type of solvent, ionic liquids (ILs) are considered to be promising in the field of CO2 capture. Due to the lack of typical industrial process cases, it is necessary to conduct a life cycle assessment (LCA) to determine the environmental performance of IL-based chemical processes and explore possible improvements. In this work, the LCA method is used to evaluate the carbon capture and storage (CCS) process from the solvent production stage to the use stage with [bmim][Tf2N] IL as the CO2 absorption solvent. The effects of different processes and CO2 capture ratios on the environmental performance of CCS-IL are also explored, and some suggestions for improvement are provided. The LCA results show that the main environmental impact stage of the CCS-IL process is the solvent production stage, which has effects that are far beyond the environmental impact of the solvent use stage, and anion production is the main factor. The LCA results of the solvent use process show that optimization of the CCS-IL process can reduce the environmental burden of the solvent use stage. From the perspective of the global environment, the introduction of waste heat resources into the CCS process will have a positive impact on the environment. The sensitivity analysis shows that reducing the CO2 capture ratio can reduce the environmental burden of the CCS-IL process, but it requires factories to bear a higher carbon tax and environmental responsibility. LCA analysis will help decision makers to further understand the IL-based chemical process and conduct accurate evaluations.