Kinetics, products, and mechanism of ethane destruction in corona discharge: Experiments and simulation

Abstract

Ethane destruction in corona discharge was studied in a flow reactor. Samples from the reactor were analyzed by GC/MS and on a quadrupole mass spectrometer. Corona discharge was initiated at atmospheric pressure and room temperature in a cylindrical flow reactor with a dielectric barrier and an axial high-voltage electrode. The flow rate of the initial mixture was varied between 0.17 and 4.8 cm3/s; the discharge power, between 0.01 and 8.0 W. The radiation yield was 0.5 molecule/100 eV for 1% ethane in air. Simulation was carried out using the kinetic mechanism consisting of 809 reactions involving 85 types of molecules, atoms, radicals, and excited species. The so-called free-radical mechanism that we developed led to an underestimated ethane destruction efficiency. The model qualitatively describes the product composition and the concentrations of its main components, but it provides no quantitative fit to experimental data, particularly for low initial ethane concentrations. New products hitherto unreported in the literature—methyl nitrate, ethyl nitrate, and acetic acid—were identified and quantified. The results are interpreted in terms of ionic reactions as a part of the destruction mechanism. These reactions are of particular significance in dilute mixtures and at low hydrocarbon concentrations in the initial mixture.