The dissociation of CO₂ in the absence of CH₄ in microwave plasma was investigated to provide a better understanding in the complexity of plasma chemistry in dry reforming reaction. The maximum conversion was achieved by using argon as a plasma carrier gas and operated at 90 Torr and the least amount of CO₂ feed ratio. The conversion was independent of absorbed power and the reaction followed the path of a chemical equilibrium. The energy efficiency was less than 4% showing the ineffectiveness of coupling micsowave power into CO₂. ₂...[ Read more ]

The dissociation of CO₂ in the absence of CH₄ in microwave plasma was investigated to provide a better understanding in the complexity of plasma chemistry in dry reforming reaction. The maximum conversion was achieved by using argon as a plasma carrier gas and operated at 90 Torr and the least amount of CO₂ feed ratio. The conversion was independent of absorbed power and the reaction followed the path of a chemical equilibrium. The energy efficiency was less than 4% showing the ineffectiveness of coupling micsowave power into CO₂.

Syngas (CO + H₂) production was also investigated using the dry reforming of methane with carbon dioxide in a microwave plasma system. The plasma reactor was operated at room temperature and sub-atmospheric pressure. The low pressure environment allowed the plasma to be sustained at 360 W without requiring any noble gas to be present, in contrary to what was observed in CO₂ dissociation. In addition, dry reforming reaction did not approach chemical equilibrium as in CO₂ dissociation, but rather followed the path of a kinetically-controlled regime. Maximum CO₂ and CH₄ conversions of 99% and 100% were achieved at a CH₄/CO₂ feed ratio of 1.0 and a corresponding H₂/CO product ratio of 0.92, which serves as a suitable feed ratio for mixed alcohols synthesis. Product selectivity towards H₂ and CO remained over 99% under these conditions, with only trace amounts of other forms of hydrocarbons and water vapour detected. Variation of pressure between 90 Torr to 300 Torr affected the plasma stability more than conversion. A maximum energy efficiency of 24% was achieved at an energy density of 16 J/scc.