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Title: Computational modeling of CO 2 conversion by a solar-enhanced microwave plasma reactor

The use of renewable energy to convert carbon dioxide (CO2) into higher-value products can help meet the demand for fuels and chemicals while reducing CO2emissions. Solar-Enhanced Microwave Plasma (SEMP) CO2conversion aims to combine the scalability and sustainability of solar thermochemical methods with the high efficiency and continuous operation of plasmachemical approaches. A computational study of a built SEMP reactor operating with up to 1250 W of microwave power together with up to 525 W of incident solar power at atmospheric pressure is presented. The study is based on a fully-coupled 2D computational model comprising the description of fluid flow, heat transfer, Ar-CO2chemical kinetics, energy conservation for electrons and heavy-species, electrostatics, and radiative transport in participating media through the discharge tube, together with the description of the microwave electromagnetic field through the waveguide and the discharge tube. Numerical simulations reveal that the plasma is concentrated near the location of incident microwave energy, which is aligned with the radiation focal point, and that CO2decomposition is highest in that region. The incident solar radiation flux leads to more uniform distributions of heavy-species temperature with moderately greater values throughout most of the discharge tube. Modeling results show that, at 700 W of electric power, conversion efficiency increases from 6.8% to 10.0% with increasing solar power from 0 to 525 W, in good agreement with the experimental findings of 6.4% to 9.2%. The enhanced process performance is a consequence of the greater power density of the microwave plasma due to the absorption of solar radiation.

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Author(s) / Creator(s):
; ;
Publisher / Repository:
IOP Publishing
Date Published:
Journal Name:
Plasma Sources Science and Technology
Page Range / eLocation ID:
Article No. 065018
Medium: X
Sponsoring Org:
National Science Foundation
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