Single step methane conversion into liquid oxygenates using multiphase flow, microplasma reactor

Direct synthesis of oxygenates (CH₃OH, HCHO, HCOOH) via methane partial oxidation at room temperature was demonstrated using multi-phase flow, non-thermal discharge microreactor. Production of active oxygen by dielectric barrier discharge is essential to initiate methane partial oxidation, while methane dissociation by electron impact is minor contribution. Heat generated by methane oxidation is removed efficiently in the microreactor configuration: liquid components are condensed on the wall and separated from O₂-rich plasma field. Furthermore, pulsed water injection washes out condensed oxygenates and suppresses successive destruction, enabling selective synthesis of oxygenates while high methane conversion is possible in a single reactor. Oxygenates were synthesized with one-pass yield of 5%-20% with 70-30% selectivity. In addition, syngas was produced with 40% selectivity and H₂/CO = 1. Assuming catalytic DME synthesis as a post discharge process, the overall yield for synthetic fuels could increases up to 30% with 80% selectivity.