An Integrated Vacuum Carbonate Absorption Process Enabled with an Enzyme Biocatalyst for CO_2 Absorption

摘要

A potassium carbonate-based absorption process for post-combustion CO_2 capture is being developed at the University of Illinois at Urbana-Champaign. A unique feature of the process is its ability to use either a waste steam or a low quality steam from the power plant's low pressure turbine to significantly lower energy use and related parasitic power loss of CO_2 capture. The process uses a biocatalyst, carbonic anhydrase (CA) enzyme to enhance the CO_2 absorption rate into the potassium carbonate (PC) solution. A process simulation study concluded that energy use performance of the process is 20-30% lower than a conventional mono-ethanol-amine process. One activity of the process development study has been evaluating catalytic reactivities and stabilities of two CA enzymes at elevated temperatures and in the presence of sulfate, nitrate and chloride impurities under typical operating conditions of the process for up to six months. Results to date indicate that CA enzyme is an effective biocatalyst to accelerate the CO_2 absorption into the PC solution.