Novel, Biological, Sustainable and Low Energy CO2 Separation - Alternative Solvents Investigation and Bench-Scale Evaluation

This project proposes to develop a novel biological, sustainable and low energy. CO2 scrubbing technology from waste gases. Specifically, we will use natural and then engineered carbonic anhydrase (CA) enzymes to catalyze the reactive absorption of CO2 into aqueous alkaline solvents, thereby selectively removing CO2 from mixed gas streams. In the proposed process, under alkaline conditions, CA catalyzes the reaction of CO2 with water to form bicarbonate in a countercurrent gas-liquid absorber column and catalyzes reverse reaction from bicarbonate to CO2 in the stripping column. The overall concept is shown in Fig. 1. To overcome the high energy requirement of traditional monoethanolamine (MEA)-based CO2 scrubbing process, we aim to develop more efficient technology by: 1) improving the robustness of CA, including tolerance to high temperature, high solvent concentration and high pH; 2) improving CA longevity using biodegradable enzyme-entrapping polymeric structures (BEEPS); and 3) utilizing compatible environmentally friendly solvents to improve process sustainability. The project will demonstrate the technology at bench-scale and support TEA and LCA enabling 20% energy reduction compared to the MEA reference case (at 90% CO2 capture), a favorable sustainability profile, and potential for capital savings due to use of benign solvents. This technology can be deployed to many industries that generate waste gases to capture CO2 from biopower, fossil-based power plants, biogas productions and to upgrade natural gas, biogas and CO2 for revenues.