The Study of CO2 Conversion in a Microwave Plasma/Catalyst System.

[摘要] The continual and increasing use of fossil fuels throughout the world has advanced concerns of atmospheric carbon dioxide (CO2) concentrations, causing a swell of scientific effort to mitigate the predicted effects of global warming. While several technological and public policy efforts have been proposed, none seem to address eliminating the actual problem, the carbon dioxide molecule. One possible solution to address this challenge is the use of a plasma source to break the molecule into carbon monoxide (CO) and oxygen.The CO can be filtered out for use in chemical and industrial processes, or CO can be added to hydrogen to create synthesis gas. This dissertation experimentally investigates the conversion of CO2 to CO in an atmospheric pressure microwave plasma/catalyst system. Diagnostics such as mass spectrometry and optical emission spectroscopy are used to identify the gas species present after plasma treatment and to measure the defining plasma properties, temperature and density. The CO2 gas is first treated with plasma alone, and then is treated with a combination of plasma and rhodium (Rh) catalyst material. In conjunction with the experimental work, computational studies of plasma CO2 dissociation are performed using a global kinetic model to determine the theoretical gas species densities resulting from electron-impact and gas phase reactions.While the plasma system alone was able to achieve a 20% energy efficiency, the Rh catalyst actually caused a drop in efficiency due to reverse reactions occurring on the surface. A total cost analysis of the existing system has shown that it does not meet the necessary energy efficiency requirements to be competitive against current technological capture and storage options. However, with the addition of hydrogen or water vapor the plasma system could create a usable product of hydrocarbons, essentially lowering the overall economic cost of the dissociation process. A plasma CO2/H2O dissociation system could present a legitimate solution to controlling excess anthropogenic carbon emissions.

[发布机构] University of Michigan

[效力级别] Carbon Dioxide

[关键词] Microwave Plasma;Carbon Dioxide;Energy Efficiency;Dissociation;Engineering (General);Physics;Engineering;Science;Applied Physics