Kinetic insights into plasma-assisted low-temperature oxidation of propane with synchrotron photoionization mass spectrometry

The present study investigates the chemical kinetics of low-temperature oxidation of propane activated by nanosecond pulsed dielectric barrier discharge in a flow reactor. Molecular beam mass spectrometry with tunable synchrotron vacuum ultraviolet photoionization (SVUV-PIMS) is employed for components identification and quantification. A series of hydrocarbons and oxygenated intermediates are observed, including fuel-specific species reported for the first time in this system like propyl hydroperoxide (C 3 H 7 OOH), acrolein (C 3 H 4 O 2 ), oxetane (-CH 2 CH 2 CH 2 O-), methyloxirane (-CH(CH 3 )CH 2 O-), and propanol ( n -/ i -C 3 H 7 OH), which provide original kinetic information in the plasma-assisted low-temperature oxidation of propane. The detection of alkyl hydroperoxide (ROOH) demonstrates the existence of alkyl peroxy (RO 2 ) formed through oxygen addition to alkyl (R) and the detection of cyclic ethers provides evidence for the presence of hydroperoxyl alkyl (QOOH). A kinetic model incorporating plasma chemistry and combustion chemistry is developed for plasma-assisted oxidation of propane. Path fluxes of fuel consumption and oxygenated intermediates formation are provided based on model analysis. Besides H abstractions by the OH radical, reactions activated by plasma involving electron impact dissociation, O( 1 D)/Ar * quenching dissociation, and ionization contribute much to fuel consumption. The formed propyl ( n -/ i -C 3 H 7 ) are exclusively consumed through oxygen addition producing propyl peroxy ( n -/ i -C 3 H 7 O 2 ). Propyl peroxy can participate in self- and cross-reactions yielding various oxygenated intermediates such as aldehydes, ketones, alcohols, and propoxy ( n -/ i -C 3 H 7 O). Discrepancies between simulations and experiments suggest that further kinetic studies on low-temperaturemechanisms, including propyl peroxy related reactions for plasma-assisted combustion modeling, are still desired.& COPY; 2022 The Combustion Institute. Published by Elsevier Inc. All rights reserved.

Automated summary

The present study investigates the chemical kinetics of low-temperature oxidation of propane activated by nanosecond pulsed dielectric barrier discharge in a flow reactor. Molecular beam mass spectrometry with tunable synchrotron vacuum ultraviolet photoionization (SVUV-PIMS) is employed for components identification and quantification. A kinetic model incorporating plasma chemistry and combustion chemistry is developed for plasma-assisted oxidation of propane.