464972 Nondimensional Specific Energy Index for Methane Pyrolysis in Thermal Plasma
In this work, we introduced a nondimensional specific energy index, defined as the ratio of supplied power and enthalpy flow needed for plasma weighted with inert gas and methane content, to better evaluate the influences of supplied power and methane content in feed on the methane pyrolysis. This nondimensional value stands for the excess of energy needed for plasma and includes both the influences of energy provided for per unit of gas and methane content. It is worth noted that compared with enthalpy change of gas in plasma, reaction heat of methane to acetylene is negligible. In an ideal process, the index value should be 1, which means that the supplied power is precisely sufficient to maintain the plasma and the reaction. A series of experiments in a 2 kW DC plasma reactor were carried out to testify the applicability of the index. The experimental results showed that the conversion of methane increased from around 10% when the index was 0.5~0.6, and reached 90% when the index was 1.0~1.2, then slowly increased to a maximum around 95%~97% when the index kept increasing. This means that this nondimensional index positively correlates to the conversion and implies the energy excess state of the system as expected.