Chemical Feedback and Control of Chemical Processes Using Non-Equilibrium Plasmas

A small-scale energy production plant must deal with variations in feedstock composition and flow properties near fossil resources. We use non-equilibrium plasmas and observe that varying the applied electric field, discharge frequency and specific energy input (SEI) maintains constant product selectivity and reactant conversion in the partial oxidation of methane. When SEI is constant, we observe that selectivity toward methanol remains constant and conversion of methane decreases with increasing voltage. Whereas for a given feedstock composition, changing SEI exchanges selectivity for conversion. We develop scaling and kinetic laws to describe this thermodynamic constraint and use it to select methanol production and methane conversion for different compositions and applied electric fields. We show that with fluctuations in feedstock composition at the reactor inlet, changing SEI and voltage enable dynamic control over the selectivity and conversion. Our measurements demonstrate that non-equilibrium plasmas, in combination with a feedback loop, enable active control over product purity and selectivity for chemical processes over distributed scales.