Non-thermal plasma degradation of tar in gasification syngas

Abstract

The dielectric barrier discharge (DBD) technology was examined using a non-thermal plasma reactor for the degradation of tar formed in a fluidized bed gasification reactor which is the absence of oxygen in the syngas. Under the same gasification conditions, the effect of specific energy density (SED) on the tar removal efficiency was investigated. The experimental results indicated that the removal efficiency of tar in the syngas increased with SED, demonstrating the possibility of tar removal by the DBD technology. The removal efficiency of tar reached above 85% at an SED of 706 J/L. The gaseous and liquid products were further analyzed in a gas chromatography and mass spectrometer (GC–MS). During discharge, the content of aromatic and long chain aliphatic hydrocarbons in the treated syngas was found to decrease, while the amount of the gaseous hydrocarbons increased. Most of the aromatic hydrocarbons were found to be converted into less toxic substances of smaller molecules containing less numbers of carbon atoms. Based on the analytical results above, the degradation mechanism of tar in the DBD process was also discussed with toluene as a model.