A counter-current flow micro-packed-bed DBD plasmatron for the synthesis of a methylated cobaloxime. (24th February 2021)

• Record Type: Journal Article
• Authors: Liu, Yukun; Sabio, Jasmine C; Hartman, Ryan L
• Is Part Of: Journal of physics. Volume 54:Number 19(2021)
• Publication Date: 2021-02-24
• Subjects: non-thermal plasma -- methylation -- multiphase flow -- dispersion -- plasma catalysis; Physics -- Periodicals; 530
• DOI: 10.1088/1361-6463/abe488
• Languages: English
• ISSNs: 0022-3727

Abstract

Abstract: An atmospheric, dielectric-barrier discharge µ -plasmatron was designed, fabricated, and applied to synthesize a methylated organometallic complex. The design comprises counter-current flow to packed-bed microstructures to facilitate gas–liquid and plasma–liquid mixing. Micropillars arranged in a staggered configuration served as a porous media for the optimum 2D mixing of components that replenish plasma-liquid interfaces. Longitudinal dispersion was characterized through residence time distribution (RTD) measurements. The experimental RTD data were then described by an axial dispersion model with a time delay parameter. Levenspiel number ( lv ) indicating the intensity of axial dispersion was estimated in the range of 20.1–374, indicating that a dispersion model should be accounted for in plasma-assisted reaction kinetics development. Stable plasma excitation of methane-helium gas mixtures was observed within the 2D porous media, by in-situ optical emission spectra, while applying an alternating high voltage across the dielectric barrier. This novel technique made it possible to confirm in-situ formations of methyl radicals. Interestingly, the porous media served as a static mixer as no discrete plasma streamers were observed. To investigate its utility, an example homogeneous cobalt catalyst was injected into the µ -plasmatron and methylated. Our findings potentially introduce a new plasma-assisted reactor design and methodology for the synthesis of methylated cobaloxime.