Life Cycle Environmental Implications of CO2 Capture and Sequestration with Ionic Liquid 1-Butyl-3-methylimidazolium Acetate

Abstract

In this paper, for the first time, we present findings on the life cycle environmental implications of an ionic liquid (1-butyl-3-methylimidazolium acetate, [bmim]+[Ac]−)-based carbon capture and sequestration (CCS) process retrofitted to a coal-fired power plant. Ionic liquids are considered as promising alternative solvents to currently proven technology based on monoethanolamine (MEA). The results indicate that a CCS process with 90% CO2 capture efficiency based on [bmim]+[Ac]− reduces life cycle greenhouse gas (GHG) emissions by only 50%. This does not compare favorably with 75% life cycle GHG reductions offered by the MEA-based CCS process. In depth analysis reveals that despite lower total energy requirements for the ionic liquid process the increased need for electricity results in poor environmental performance. The insights gained from the results of the ionic liquid [bmim]+[Ac]− CCS process is used to explore critical life cycle environmental performance parameters and trade-offs in the context of future design of functionalized ionic liquids for CO2 capture. This work will aid energy system and policy analysts to understand the full implications of future ionic liquid-based CCS systems.