Combustion and Reformulation Characteristics of Biogas in Plasma Assisted Combustion Using Microwave Induced Non-Equilibrium Plasma

摘要

To utilize biogas validly, we have applied plasma assisted combustion using microwave to the combustion and reformulation of biogas. In this study, the characteristics of combustion and reformulation of biogas have been investigated by comparing of large and small nozzle. In case of small nozzle, the combustion and reformulation of biogas stably occurs over a wider equivalence ratio area than that in case of large nozzle, because the damping of microwave is inhibited. N_2 and OH radical decrease, and H_α, CO, CH and C_2 radicals increase as equivalence ratio. H_2 and CO concentrations increase, and CO_2 concentration decreases with increasing equivalence ratio. In this method, since the reaction of CO_2 + e → CO + O occurs, the amount of CO_2 of produced gas is less than the amount of supplied CO_2 in high equivalence ratio region. Cold gas efficiency increases with increasing H_2 and CO concentrations. When CH_4 is completely reformed into H_2 and CO, cold gas efficiency is about 95%. However, the maximum value of cold gas efficiency is approximately 110% at small nozzle, because CO_2, which does not have calorific value, is decomposed into CO, which has calorific value.