Dissociation of carbon dioxide using a microhollow cathode discharge plasma reactor: effects of applied voltage, flow rate and concentration

Abstract

This paper reports an experimental study on dissociating carbon dioxide (CO 2 ) using a microhollow cathode discharge (MHCD) plasma reactor operated at 1 atm. The MHCD plasma reactors can be a promising technology for dissociating gases, including CO 2 , as they do not require catalysts, they operate at around room temperature, and can be inexpensively built and operated. In this study, CO 2 balanced with the carrier gas argon (Ar) was fed through the MHCD reactor, and parametric experiments were conducted to investigate the effects of applied voltage, flow rate, and CO 2 mole fraction in the influent on the composition of the products, energy conversion efficiency, and yield. Within the investigated parameter ranges, the maximum energy conversion efficiency of 14% was achieved when the specific energy input was 1.1 eV mol −1 , whereas the maximum CO yield of 10.5% was achieved when the specific energy input was 4 eV mol −1 . The results also showed that diluting CO 2 with Ar increased the yield at an expense of a decrease in energy conversion efficiency. The results of this study provide insights for operating MHCD reactors for efficient gas dissociation at atmospheric pressure.

Carbon dioxide dissociation to carbon monoxide by non-thermal plasma

“…CO + 1/2 O 2 (DH = 280 kJ/mol) decreases with the conversion, as already mentioned by several authors [20][21][22]28] and is much lower for pulsed plasma than for AC sinusoidal activation. Whatever the plasma activation mode, we observed a decrease in the energy efficiency with He dilution, at constant total input energy (Tables 1 and 2).…”

Calculated low-energy electron-impact vibrational excitation cross sections for CO2molecule

“…The calculations assume decoupling between normal modes and employ the local complex potential model for the treatment of the nuclear dynamics, usually adopted for the electron-scattering involving diatomic molecules. Results are presented for excitation up to 10 vibrational levels in each mode and comparison with data present in the literature is discussed.One of the technological problems, connected with strategies for reduction of the global warming coming from the greenhouse effect produced by carbon dioxide, is represented by the capture at source and storage of the CO 2 gas, mainly based on the plasmolysis process leading to the splitting of CO 2 into CO molecules and atomic or molecular oxygen [1,2]. The efficiency of the dissociation processes is strongly determined by the vibrational activation of the molecule.…”

Effects of reactor geometry on dissociating CO2 and electrode degradation in a MHCD plasma reactor

“…Figure (a) shows SEI at different dielectric thicknesses as a function of residence time. Residence time and SEI were selected as the comparison parameters, as they mainly affect the performance of the reactor for gas dissociation . At a residence time of 12 μs, SEI decreased by 43% and 16% as the dielectric thickness increased from 150 to 300 μm and 300 to 450 μm, respectively.…”

“…They reported CO 2 conversion of 47% at 33 kPa and ammonia conversion of 30% at 93 kPa. Taylan and Berberoglu excluded the need for low pressures to increase the overall energy efficiency and experimentally dissociated CO 2 in a MHCD reactor at 1 atm. They reported the effects of operating conditions, such as applied voltage, flow rate, and concentration of carrier gas on the CO 2 conversion and efficiency, and showed promising results by reporting a maximum efficiency of 13.7% and conversion of 10.5%.…”