The conversion of carbon dioxide has been studied using a microwave plasma. A plasma is a highly energetic state of matter created by applying an intense high frequency electromagnetic field to a low pressure gas. Energy transfer mainly occurs as a result of energetic electrons colliding with gas molecules, which may then be activated at a relatively low temperature reducing the energy barrier to reaction. Two reactions were examined in this study. _{2 2 2 2}...[ Read more ]

The conversion of carbon dioxide has been studied using a microwave plasma. A plasma is a highly energetic state of matter created by applying an intense high frequency electromagnetic field to a low pressure gas. Energy transfer mainly occurs as a result of energetic electrons colliding with gas molecules, which may then be activated at a relatively low temperature reducing the energy barrier to reaction. Two reactions were examined in this study.

1)The Decomposition of carbon dioxide: Four parameters, CO₂ feed concentration, input power, operating pressure and total flowrate were investigated. CO₂ conversion was found to decrease with increasing CO₂ feed concentration. Incident power and total gas flowrate did not show any significant effect at both 20vol% and 50vol% CO₂ feed concentration. A low operating pressure was observed to favor CO₂ conversion and plasma stability. Effluents were analyzed by gas chromatography. CO and O₂ were main products and no carbon deposition on the quartz reactor was observed. Also, CO₂ decomposition is suggested to be an equilibrium radical reaction. Both CO and air and were shown to be product inhibitants other than acting as diluents to the reaction.

2) Carbon dioxide reforming of methane The effect of methane on carbon dioxide conversion was examined at a fixed set of operating conditions. It was shown that the carbon dioxide conversion was found to increase with decreasing carbon dioxide to methane feed ratio, and methane was generally all converted during the reaction. Carbon deposition was found to occur at methane to carbon dioxide ratios greater than or equal to one, which also resulted in the plasma being extinguished. Competition for oxygen atom between carbon monoxide and water was observed to determine the quantity of product- hydrogen formed. Finally, the position of the tube after the plasma was shown to have no effect on the conversion of CO₂.