Michael C. Trachtenberg

Enzyme Based Membrane Reactor for CO 2 Capture

Control of carbon dioxide (CO 2 ) is crucial for all crew inhabited space-flight missions. Air revitalization requires safe and reliable CO 2 extraction systems characterized by small volume, low mass, low rate of energy use, minimal use of consumables, and little or no crew time for operation and maintenance. Current designs are relatively costly to operate due to consumable usage rates (e.g., LiOH), high mass and/or volume (solid amines), and/or high energy costs associated with regeneration of CO 2 adsorption capacity (e.g., metal oxide). Our work focuses on the development of a highly efficient enzyme catalyzed, Carbonic Anhydrase based liquid membrane biomimetic reactor. We report here on the use of aqueous chemistry modeling to guide the design of new liquid membrane compositions. We examine the effects of these new solutions on enzyme activity and on the solubility of other gases in the mix. We also discuss our initial efforts to enhance reactor performance through localized pH control.

Flue gas CO2 capture by a green liquid membrane

Publisher Summary This chapter presents the results of a 1-dimensional reactive transport model and demonstrates a hollow fiber reactor design that allows multiple degrees of freedom in construction to optimize extraction fraction. Simulation was carried out by solving 1-dimensional reactive transport equations with appropriate boundary conditions. All physical properties such as gas solubilities and diffusivities were taken from available open literature sources. Results suggest that separation performance is highly dependent on both the process parameters and reactor inherent parameters. Consequently, simulations were done by varying a variety of parameters such as enzyme concentration, liquid membrane composition, and thickness; with the goal to maximize the overall performance for a given CO2 feed concentration. Facilitated transport is limited by the chemical thermodynamics. The maximum facilitation occurs when all chemical reactions involved are at chemical equilibrium. Facilitation is achieved by means of the most efficient CO2 conversion catalyst, carbonic anhydrase. Simulation can predict the system performance and can be a valuable tool for the optimization of the CO2 capture process.