NTP-assisted partial oxidation of methane to methanol: effect of plasma parameters on glass-packed DBD

Abstract

The partial oxidation of methane to methanol was performed in a non-thermal dielectric barrier discharge (DBD) plasma reactor. The influence of various parameters on the conversion of methane, product selectivity and energy efficiency has been studied. Typical results indicate that the discharge gap has a marked influence on methane conversion and product distribution. The best selectivity to CH 3 OH and HCHO was ~25% and ~17% at a discharge gap of 4.5 and 5 mm, respectively, and the highest corresponding energy efficiency was ~0.9 mmol kJ −1 . At a later state, the DBD reactor was operated under a packed-bed configuration by integrating the discharge gap with zero surface glass materials having different geometry: glass beads (spherical), glass capillary (hollow cylindrical) and glass wool (spongy honeycomb) to understand the influence of material geometry on the plasma discharge and finally on the formation of products such as CH 3 OH, HCHO, CO, CO 2 , H 2 , C 2 H 6 . Typical results indicated that the morphology of the packing materials affects the discharge characteristics, and hence the product distribution. It is concluded that the better performance of the packed-bed plasma reactor is due to the improved electrical field strength. Among the geometries studied, glass wool showed the highest CH 4 conversion due to the improved field strength/surface corona, whereas glass-bead packing improved the CH 3 OH selectivity to ~32%.

Fundamental Properties and Applications of Dielectric Barrier Discharges in Plasma‐Catalytic Processes at Atmospheric Pressure

“…The investigated setups featured DBD reactors with transition metal oxides as catalysts. A variety of materials was used and yields of up to 12 % were reported for Mn 2 O 3 [133] and CuO [135,136], but further optimization of the catalysts is expected. Processes without catalyst integration also manage to produce methanol, but in lower quantities, indicating a synergistic effect of plasma catalysis.…”

“…In addition to the optimization of the methanol yield, an improvement of the product distribution is also desirable. Common by‐products in the selective oxidation of methane process are HCHO, CO, CO 2 and C 2 H 6 , .…”

Plasma‐Assisted Reforming of Methane

“…[ [135][136][137][138][139][140][141][142][143][144][145] Parallel-plate DBD reactor 1) Typical characteristics are similar to coaxial DBD reactors. 2) Poor air tightness and increased operating costs due to its parallel-plate structure.…”

Dry Reforming of Methane under Mild Conditions Using Radio Frequency Plasma

“…Using plasma technology also this route is available. [31][32] Our work builds upon the work on methane activation by Mozetic et al We utilize lower power, flow and pressure and discover that C2 compound formation decreases together with increased formation of H2. This is a relevant finding for DRM.…”