Removal of toluene as a biomass tar surrogate by combining catalysis with nonthermal plasma: understanding the processing stability of plasma catalysis

Abstract

In this study, toluene (tar surrogate) removal under a simulated gasification gas (SGG) atmosphere was conducted by combining DBD plasma with a nickel catalyst. The processing stability of plasma catalysis was investigated in terms of toluene removal and SGG reactions, and some attempts at stability improvement including the addition of H₂ or H₂O and K-modification of the catalyst were conducted. The results indicate that plasma exerts great effects on the carbon deposition rate on the plasma-covered catalyst surface to affect the processing stability, and the effect, increasing or to some extent decreasing the carbon deposition rate, depends on the operating conditions and catalysts. In a Ni/γ-Al₂O₃ reactor with a SGG atmosphere and H₂ or H₂O addition, the higher carbon deposition rate induced by plasma leads to poor stability, while under the high H₂O addition amount condition, the activation effect of plasma combined with the H₂O/CO₂ adsorption enhancement of K-modified Ni/γ-Al₂O₃ prevented the higher carbon deposition rate in the plasma-covered area and hence successfully improved the processing stability.