Experimental study on benzene removal of fuel gas in a packed-bed dielectric barrier discharge reactor

A packed-bed dielectric barrier discharge (DBD) reactor was developed to investigate the removal of biomass tar in fuel gas atmosphere, and benzene was used as the tar surrogate. The effects of fuel gas composition, packing materials, reaction temperature and reduction methods of catalysts on the removal efficiency of benzene were investigated. The results indicate that the benzene removal efficiency of air-gasification fuel gas is close to that of steam-gasification fuel gas at low temperatures, but the presence of O₂ in the fuel gas leads to a large drop in the removal efficiency. In addition, the enhancement of the plasma discharge power and the use of packing materials with higher permittivity, specific surface area and pore volume can improve the benzene removal efficiency. For the plasma-catalytic process, the combination of DBD plasma and Ni/γ-Al₂O₃ (C) shows a significant benzene removal potential. The benzene removal efficiency decreases with temperature from 230-330℃, reaching a minimum value of 11.6%, and then notably increases to 85.4% at 430℃. Furthermore, the combination of plasma and Ni/γ-Al₂O₃ (P), which is reduced by plasma under H₂ atmosphere, has a similar tendency of benzene removal behavior within the temperature range of 230-430℃, reaching a maximum removal efficiency of 90.0% at 430℃ due to higher specific surface area and nickel dispersion of Ni/γ-Al₂O₃ (P). Moreover, the increased CH₄ concentration induced by the methanation of the fuel gas and the slightly decreased heating value of the fuel gas are obtained in the plasma-catalytic process.