Migration-Assisted Water Gradient Process for a Continuous CO2 Capture

Stabilizing atmospheric CO₂ will require a significant reduction in anthropogenic CO₂ emission
sources like coal-fired power plants. The current industrial processes such as calcium looping,
amine scrubbing, and oxyfuel combustion capture CO₂ from the exhaust flue gases but are
extremely energy-intensive. Water-driven CO₂ capture techniques are in their infancy but are
particularly attractive due to their low energy penalty. In this work, we develop a continuous CO₂
capture device utilizing the ability of CO₂ to be in a carbonate-bicarbonate equilibrium in the
presence of water. The incoming CO₂ is captured in a CO₂ -binding organic liquid. The captured
CO₂ is allowed to diffuse through an anion exchange membrane to an aqueous medium where it
can either be sequestered or transformed into usable products. To enhance the CO₂ capture rate,
the diffusion of the captured CO₂ is accelerated by applying an electric field across the device.
The performance of this capture technique is evaluated under various operating parameters such
as the composition of the gas, relative humidity, temperature, the effect of concentration of SO_x ,
and gas flow rate. Additionally, for the device configuration, effects of the operating
temperature, type of membranes, percentage of the solvent, solvent circulation flow rate, and
applied current are reported.