Selective Oxidation of Methane to Methanol and Formaldehyde with Nitrous Oxide in a Dielectric-Barrier Discharge−Plasma Reactor

Abstract

The partial oxidation of CH 4 with N 2 O in Ar has been investigated at atmospheric pressure in a dielectricbarrier (silent) discharge plasma induced by low input power in a range from 0.27 to 7.71 Wh(Ncm 3 ) -1 . In an Ar stream, about 10% of the combined yield of CH 3 OH and HCHO and 40% of the selectivity to these products were achieved, with CO being the other major product. Low power favored selectivities to unstable partial oxidized products and supressed further decomposition to carbon oxides and carbonaceous deposits on the electrode surface. Kinetic and spectroscopic observations indicated that Ar carrier gas played an important role in the highly selective oxidation of CH 4 to CH 3 OH and HCHO via energy transfer from excited-state Ar species to the reactant molecules under the mild conditions examined.

Gas-to-liquids process using multi-phase flow, non-thermal plasma microreactor

“…Research efforts are being directed at direct methods to generate oxygenates in homogeneous gas phase reactions [1], over solid catalysts [8] and using ionic liquids [9]. As yet another alternative, an atmospheric pressure nonthermal discharge method was used for partial oxidation of methane to oxygenates (mainly methanol, formaldehyde and formic acid) at ambient temperatures [10][11][12][13][14][15][16]. Active radicals generated in the discharge by dissociation of feed molecules initiate the reactions to produce oxygenates.…”

Methane Conversion to C2 Hydrocarbons Using Dielectric-barrier Discharge Reactor: Effects of System Variables

“…They showed that methanol formation increases with exclusion of oxygen in the feed with methane and reaching a maximum at about CH 4 /O 2 = 20, and its selectivity is independent of applied voltage after a certain value. Matsumoto et al [13] investigated the oxidation of methane to methanol and formaldehyde in DBD plasma. They used low input power in a range from 0.27 to 7.71 Wh/Nm 3 .…”

Direct Conversion of Methane into Methanol and Formaldehyde in an RF Plasma Environment I: A Preliminary Study

“…The conversion of CH 4 (X CH4 ) and fraction of total input carbon converted into CH 3 OH (F CH3OH ), HCHO (F HCHO ) and C 2 H 2 + C 2 H 4 + C 2 H 6 (F C2 ) were calculated as, Unlike in other studies (Matsumoto, et al 2001), X CH4 was less than 12% at a 2% CH 4 feeding concentration, and a 50 cm 3 /min -1 total flow rate, while X CH4 was about 4% with a 5.0 mL/min -1 CH 4 flow rate (Taylor et al 2000). X CH4 with typical solid catalysts reported by Otsuka (2001) was 0.7% to 18.5%.…”

“…In the RF system, applying 50W yielded 14.8 to 38.1% CH 4 conversion, while in the DBD system, 100W of input power yielded 5.97% CH 4 conversion (Jiang et al 2002). Matsumoto (2001) stated that the intensities in Ar excitation drastically declined upon the introduction of a feeding concentration of CH 4 of only 2% into the Ar stream, and their system exhibited a large energy transfer from excited Ar species to reactant molecules. This suggestion was extended to the RF system.…”