Steam reforming of methane in a temperature-controlled dielectric barrier discharge reactor: the role of electron-induced chemistry versus thermochemistry

Abstract

While classic reforming processes rely on heat and chemical equilibrium, plasma-based reforming processes possess the ability to induce non-equilibrium and reactive chemistry at low temperatures using high energy electrons. To better understand the distinctive roles of both electron-induced chemistry and thermochemistry during plasma-assisted fuel reforming, we previously developed a temperaturecontrolled dielectric barrier discharge (DBD) reactor, which controlled the gas temperature and the electron temperature independently. Here, we investigate plasma-assisted steam reforming of methane using the temperature-controlled DBD reactor and electron-kinetics calculations. We investigated the individual effects of the determining factors for electron-induced chemistry (i.e., reduced electric field intensity and discharge power) and for thermochemistry (i.e., background gas temperature) by varying the discharge power, gas temperature, and pressure inside the reactor. As a result, we found that both the electron-induced chemistry and thermochemistry governed the reactant conversions. Thermochemistry positively affected the methane conversion in particular, but negatively affected the water conversion as the gas temperature increased. The electron-induced chemistry weakly affected the product distribution, while the background temperature (thermochemistry) strongly influenced the product selectivity and composition by altering the chemical pathways involving the plasma-generated reactive species at the given temperature.

Inevitable chemical effect of balance gas in low temperature plasma assisted combustion

“…This is stressed even more by the already known significant effect of N2 excited states on the plasma chemistry [1,2,[8][9][10]. For plasma assisted methane reforming, several kinetic studies in N2 are available [18][19][20][21]. Additionally, we showed that the dilution rate has a significant effect on the fraction of electron energy transferred to H2 and O2 as well as the critical E/N where the maximum energy transfer to H2 or O2 occurs.…”

Plasma-based multi-reforming for Gas-To-Liquid: tuning the plasma chemistry towards methanol

“…To investigate the possibilities of plasma-based multi-reforming, we performed chemical kinetics calculations supported by experiments. The reactor used for the experiments 26 – 28 and the chemistry set 29 (including its experimental validation) used for the calculations were presented previously. A detailed sensitivity analysis on this chemistry set was presented by Wang et al .…”

Unraveling Discharge and Surface Mechanisms in Plasma-Assisted Ammonia Reactions

“…During recent years, plasma and plasma-catalysis reactions carried out in packed-bed plasma and other types of atmospheric pressure reactors have emerged as a suitable technology to promote different gas-phase processes of high environmental impact. Examples encompass the removal of contaminants, − methane, hydrocarbons, and alcohols reforming, − or ammonia synthesis. − Advantages of plasma and plasma catalysis for these applications are their low temperature of operation, the possibility to work at atmospheric pressure or below, its straightforward downscaling to small reactor sizes, or the null induction period required to achieve steady state conditions, all together enabling a distributed application of the technology directly connected to the grid . However, these good prospects have stubbornly confronted serious and up no to now unsolved limitations such as a poor energy efficiency and low selectivity for the synthesis of given compounds.…”