Features of the Conversion of Ethylene in Air and Argon in a Barrier Discharge: Experiment and Modeling

Abstract

Abstract The oxidative and non-oxidative conversion of ethylene in a barrier discharge in the presence of water is studied. The use of a plasma-chemical reactor with a water film flowing down its walls allows efficient quenching of the formed reaction products, excluding their re-exposure to the discharge plasma. Oxidation of ethylene with air results in the formation of both oxygen-containing substances and gaseous hydrocarbons with a predominant content of acetylene. Saturated and unsaturated С1‒С5+ hydrocarbons with a predominance of compounds with four carbon atoms in the molecule are resulted from non-oxidative conversion of ethylene in an argon atmosphere. The level of ethylene conversion per pass of the reaction mixture through the plasma-chemical reactor is 12.8 and 58.9 wt% for oxidizing and non-oxidizing conditions, respectively. The efficiency of the reaction of ethylene dimerization into unsaturated hydrocarbon gases is shown in comparison with the reaction of its air oxidation into oxygenates. The results of theoretical calculations of electron energy losses in a barrier discharge for the case of air oxidation of ethylene reveal the preferential excitation of various states of nitrogen molecules. In the case of ethylene dimerization in argon, the number of excited ethylene molecules at the electronic levels increases, resulting in an increase of its conversion. A model of the chemical kinetics of ethylene conversion in a barrier discharge has been developed that includes more than 280 reactions. A good agreement between the calculated and experimental data has been obtained. New fundamental knowledge about the processes of decomposition of the ethylene molecule under the effect of electrons of a barrier discharge with an average energy of 4–5 eV have been gained through the experimentation with models.