Decoupling research on dynamic effect of graphite addition for microwave-induced discharge with spherical biomass-based char

Abstract

Microwave discharge is a special phenomenon under microwave irradiation, with higher energy efficiency over microwave heating. Microwave-induced discharge with carbon-based dielectrics is the common forms, but there are severe challenges for improving the discharge intensity. Relevant research confirmed the feasibility of microwave-induced discharge with spherical biomass-based char with graphite addition. However, the deep-stated dynamic effect of graphite addition on it is still unclear. Therefore, the work firstly studied the influence of graphite addition on the discharge intensity, and then conducted the decoupling research of the effects of dielectric properties on microwave discharge through simulation of electric field. The improvement of discharge intensity with graphite addition is related to more significant polarization of electric field. The influence of conductivity and permeability on the electric field outside and inside the dielectric is similar. Still, enhancing the conductivity was the first choice for improving the discharge intensity, particularly before an inflection point of 100 S/m. The relative permittivity and conductivity caused a coupling effect on electric field of the dielectric bed. Essentially, the increase of conductivity and relative permittivity resulted from graphite addition promotes the discharge intensity. The study offers evidence for optimizing the performance of microwave-induced discharge with carbon-based dielectrics.