Characteristics of Generic Dielectric Materials and Char as Bed Materials of a Dielectric Barrier Discharge Reactor under High Temperature and Wide Frequency Range

Abstract

This paper investigates the characteristics of generic dielectric materials and char, which are intended to be used as the fixed bed materials of a non-thermal-plasma (NTP)-based dielectric barrier discharge (DBD) reactor. Such data are very essential when upgrading the fixed bed to a fluidised bed, which may provide further improvement in the production and quality of the producer gas. This measure would eventually cause a better producer gas and effective biomass-based power generation. Pertinent data that are currently available focus on either improving the design requirements of the producer gas or studying the impact of individual dielectric-material-specific applications to produce useful gases by decomposing the polluting gases. Considering that there has only been a meagre attempt to gather this information, this study gains its importance. In this context, the collective electrical behaviour of bed materials viz. quartz-sand, olivine, and char under ambient and higher temperatures is recorded and their frequency dependencies are analysed. First, the electrical behaviour of the chosen materials is resolved over a wide frequency range. For this purpose, two test cells, i.e., one for the ambient conditions and the other for higher temperatures, are built. Subsequently, the surface and volumetric properties of the chosen bed materials under ambient and higher temperatures are studied. As these materials are not as conductive as metal, such an approach is necessary to understand the apparent behaviour of the materials and anticipate their direct or indirect effects in the presence of non-thermal plasma. In summary, the data from the test cell under ambient and higher temperatures and the influence of materials in the dielectric barrier discharge reactor qualitatively define the material usage and may provide an opportunity to optimise their performance.