Slaets Joachim, Morais Eduardo, Bogaerts Annemie
Research Group PLASMANT, Department of Chemistry, University of Antwerp Universiteitsplein 1 BE-2610 Wilrijk-Antwerp Belgium
RSC Sustain. 2025 Jan 28;3(3):1477-1493. doi: 10.1039/d4su00676c. eCollection 2025 Mar 5.
We have developed a kinetic model to investigate the post-plasma (afterglow) chemistry of dry reforming of methane (DRM) in warm plasmas with varying CO/CH ratios. We used two methods to study the effects of plasma temperature and afterglow quenching on the CO and CH conversion and product selectivity. First, quenching conductive cooling is shown to be unimportant for mixtures with 30/70 and 50/50 CO/CH ratios, while it affects mixtures containing excess CO (70/30) by influencing radical recombination towards CO, H and HO, as well as the water gas shift reaction, decreasing the CO conversion throughout the afterglow. This is accompanied by shifts in product distribution, from CO and HO to CO and H, and the magnitude of this effect depends on a combination of plasma temperature and quenching rate. Second and more importantly, quenching post-plasma mixing of the hot plasma effluent with fresh cold gas yields a significant improvement in conversion according to our model, with 258% and 301% extra conversion for CO and CH, respectively. This is accompanied by small changes in product selectivity, which are the result of interrupted reaction pathways at lower gas temperatures in the afterglow. Effectively, the post-plasma mixing can function as a heat recovery system, significantly lowering the energy cost through the additional conversion ensued. With this approach, our model predicts that energy consumption can be lowered by nearly 80% in comparison to DRM under the same plasma conditions without mixing.
我们开发了一种动力学模型，以研究在具有不同CO/CH比的热等离子体中甲烷干重整（DRM）的等离子体后（余辉）化学过程。我们使用两种方法来研究等离子体温度和余辉猝灭对CO和CH转化率以及产物选择性的影响。首先，对于CO/CH比为30/70和50/50的混合物，猝灭传导冷却显示不重要，而对于含有过量CO（70/30）的混合物，它通过影响自由基向CO、H和HO的重组以及水煤气变换反应，影响整个余辉过程中的CO转化率，导致CO转化率降低。这伴随着产物分布的变化，从CO和HO转变为CO和H，并且这种影响的程度取决于等离子体温度和猝灭速率的组合。其次，更重要的是，根据我们的模型，热等离子体流出物与新鲜冷气体的余辉后混合显著提高了转化率，CO和CH的额外转化率分别为258%和301%。这伴随着产物选择性的微小变化，这是余辉中较低气体温度下反应路径中断的结果。实际上，余辉后混合可以起到热回收系统的作用，通过随之而来的额外转化显著降低能源成本。通过这种方法，我们的模型预测，与在相同等离子体条件下不进行混合的DRM相比，能耗可降低近80%。
