A study of plasma-assisted gasification of coal in a carbon dioxide environment

The effect of electrical energy input on the gasification of coal in a fluidized bed was studied. The bed was fluidized using carbon dioxide, oxygen and argon. The volume percentages of carbon monoxide, hydrogen, methane and carbon dioxide in the off-gas were determined for coal bed temperatures ranging from approximately 200 to 950{dollar}spcirc{dollar}C. The off-gas was analyzed using gas chromatography. Yields of greater than ninety five percent of carbon monoxide and hydrogen were obtained with the average yield for plasma heated gasification around 90 vol%. The use of plasma also increased the combustion efficiency of the fluidized bed as indicated by the increase in coal combustion percentage from 39% combusted for the resistance heated system to 50% combusted for the plasma assisted systems. The effects of carbon dioxide flow rate as well as the carbon dioxide to oxygen molar ratio and the energy input into the coal bed via the bed plasma system were also examined. Theoretical modelling of the coal gasification conditions studied in this research revealed off-gas compositions which were very similar to the experimental results. This would seem to suggest that the coal gasification system was operating in equilibrium.