Destruction of gasification tar over Ni catalysts in a modified rotating gliding arc plasma reactor: Effect of catalyst position and nickel loading

In this study, a modified rotating gliding arc (RGA) plasma reactor with fan-shaped swirl generator coupled with Ni/gamma-Al2O3 catalyst was investigated for the steam reforming of gasification tar from waste materials, taking toluene as the tar surrogate. The system performance was evaluated in terms of tar conversion, energy efficiency, yield of product gas, as well as synergistic capability of plasma catalysis, with particular attention on the effects of specific energy input (SEI), positioning of the catalysts, and Ni loading of catalysts. Different characterizations of catalysts including N-2 adsorption-desorption, XRD, H-2-TPR, and TEM were conducted to study the properties of catalysts. Incorporation of catalyst placed sufficiently far from the anode increased toluene conversion which indicated the synergy between plasma and catalysis for tar conversion. A toluene conversion of up to 91.9% can be achieved with a distance of 62 mm between the catalyst and the anode, which was 21% higher than that in the plasma alone system. The toluene conversion can be further increased to 94.7% when the Ni loading was increased from 4% to 16%. The synergistic capability of plasma catalysis was demonstrated from an enhanced toluene conversion and the increased formation of value-added fuel gases such as H-2, CO, and CH4, together with simultaneously a selective reduction in CO2 formation, especially when the Ni loading was 4% and 8%. Identification of liquid by-products also revealed the synergy between plasma and catalysis which transformed biradical HC-CH into gaseous products, prohibiting the formation of indene and naphthalene.

Automated summary

This study investigated a modified plasma reactor coupled with a Ni/gamma-Al2O3 catalyst for the steam reforming of gasification tar, using toluene as a surrogate. By placing the catalyst sufficiently far from the anode, toluene conversion was increased, demonstrating synergy between plasma and catalysis. Furthermore, increasing Ni loading in the catalyst also significantly improved toluene conversion.