Improving the performance of gliding arc plasma-catalytic dry reforming via a new post-plasma tubular catalyst bed

A combination of a gliding arc plasmatron (GAP) reactor and a newly designed tubular catalyst bed (N-bed) was applied to investigate the post-plasma catalytic (PPC) effect for dry reforming of methane (DRM). As comparison, a traditional plasma catalyst bed (T-bed) was also utilized. The post-plasma catalytic effect of a Ni-based mixed oxide (Ni/MO) catalyst with a thermal catalytic performance of 77% CO₂ and 86% CH₄ conversion at 700 ℃ was studied. Although applying the T-bed had little effect on plasma based CO₂ and CH₄ conversion, an increase in selectivity to H₂ was obtained with a maximum value of 89% at a distance of 2 cm. However, even when only α-Al₂O₃ packing material was used in the N-bed configuration, compared to the plasma alone and the T-bed, an increase of the CO₂ and CH₄ conversion from 53% and 53% to 69% and 69% to 83% was achieved. Addition of the Ni/MO catalyst further enhanced the DRM reaction, resulting in conversions of 79% for CO₂ and 91% for CH₄. Hence, although no insulation nor external heating was applied to the N-bed post plasma, it provides a slightly better conversion than the thermal catalytic performance with the same catalyst, while being fully electrically driven. In addition, an enhanced CO selectivity to 96% was obtained and the energy cost was reduced from ∼ 6 kJ/L (plasma alone) to 4.3 kJ/L. To our knowledge, it is the first time that a post-plasma catalytic system achieves this excellent catalytic performance for DRM without extra external heating or insulation.