Attempting to Break the 2 GJ/tonne CO2 Barrier; Development of an Advanced Water-Lean Capture Solvent From Molecules to Detailed Process Design

Abstract

Solvent-based post-combustion CO2 capture is an energy-intensive process primarily driven by the energy required to regenerate the CO2 capture solvent. Researchers are currently focused on developing drop-in solvent replacements for commercial amine solvents with lower regeneration energies. One approach to reducing the regeneration energy of a solvent is to reduce its water content, thereby reducing unnecessary condensing and consequent boiling in the process. There are a number of water-lean solvent formulations currently under development that allow for water contents below 10% by weight, versus more than 60% for commercial aqueous amines. One solvent class, CO2-Binding Organic Liquids (CO2BOLs), shows promise to reduce the parasitic load to a coal-fired power plant but has been impeded by high viscosities at high CO2 loadings. In this paper, we perform a preliminary modeling study of a new low-viscosity CO2BOL solvent and assess the energetics of different process stripper configurations. By tailoring the process configuration with the unique aspects of the solvent reboiler duties below 2 GJ/tonne CO2 could be achievable. Further, this study suggests that there is no one-size-fits-all process optimum configuration for solvents, and therefore optimal configurations will be solvent specific.