PNNL

Abstract

Advanced carbon capture technologies are in demand to enable a transition to a low-carbon global economy. Chemical absorption using aqueous amines has been long considered as the most mature technology for capturing CO2 from point sources, but their deployment has been impeded by high costs and energy penalties. Here, we present a comprehensive techno-economic evaluation of four derivatives of CO2-Binding Organic Liquids (CO2BOLs), all water-lean solvents, as promising options towards energy- and cost-effective carbon capture from point sources. This evaluation was conducted using experimentally-measured solvent properties and rigorous plant-wide process simulations in Aspen Plus based on a U.S. Department of Energy power plant reference and 2018 pricing basis. The results suggest that water-lean formulations can minimize water condensation and vaporization during solvent regeneration, leading to a 36% energy saving compared with aqueous amines, in a typical absorption / desorption process without any complex configuration design. Indeed, all four CO2BOLs derivatives were predicted to achieve a carbon capture rate greater than 90% for the 650 MW supercritical pulverized coal reference power plant, with three of the solvents at an estimated carbon capture cost below $40/tonne CO2 at 90-97% carbon capture rate. Of all CO2BOLs, the estimated carbon capture cost is about 11-25% less expensive than the aqueous amine references with the lowest cost formulation at $38.1/tonne CO2. The CO2BOLs assessments showed that in addition to vapor liquid equilibrium and kinetics (key properties already identified for aqueous solvents in the literature), viscosity, volatility, and hydrophobicity, also have strong impacts on the energy and economic performance of water-lean solvents. These effects helped to identify future areas for further improvement.