Coke formation pathway under various reaction conditions during the production of syngas in a dielectric barrier discharge plasma environment using CeO2 nanorods supported Ni catalysts
Coke formation pathway under various reaction conditions during the production of syngas in a dielectric barrier discharge plasma environment using CeO2 nanorods supported Ni catalysts
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DOI：
10.1016/j.cej.2023.147459
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发表时间：
2023-11
影响因子：
15.1
通讯作者：
M. Hossain;Md Robayet Ahasan;Xiang Ding;Ruigang Wang
中科院分区：
文献类型：
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作者：
M. Hossain;Md Robayet Ahasan;Xiang Ding;Ruigang Wang
在固定床同轴介质阻挡放电（DBD）反应器中，采用纳米纳米棒（NR）负载的Ni催化剂，研究了等离子体辅助甲烷（DRM）的干重整。本研究分别在纯热和等离子体辅助热DRM环境下测试了催化剂载体、包装材料和10% Ni-CeO2NR催化剂，以探索等离子体-热协同作用。支撑和包装材料在450°C的热DRM下没有明显的反应性；然而，催化剂在350°C左右开始表现出反应性。另外，等离子体辅助DRM实验显示，在所有样品类型中，在明显较低的温度下都发生了明显的反应。与二氧化碳转化相比，引入等离子体可显著增强ch4转化。在等离子体辅助DRM测试中，10% Ni-CeO2NR催化剂的ch4和co2转化率随着温度的升高而增加，在450°C时分别达到52.1%和46.1%的峰值。该催化剂在等离子体环境中性能的提高可归因于NiO和CeO2NR载体之间的金属-载体相互作用的增强，这是表面氧空位浓度丰富的结果。然而，这种转化的增加伴随着碳沉积的增加。考虑到热DRM过程的贡献，确定了最佳工作温度为350℃。在此温度下，等离子体功率的增加导致了转换的增强。然而，当功率超过23.8 W时，反应路径发生改变，导致合成气输出减少。在保持等离子体功率和温度不变的情况下，提高CH4: co2原料气流量比，提高H2/CO产生量。此外，在相同的条件下，在原料气流量比不变的情况下，增加总流量，由于减少了化学停留时间，两种转化率都降低了。因此，在恒定的原料气比下，可以在较低的总流量下获得较高的合成气产量。
Plasma-assisted dry reforming of methane (DRM) was investigated using CeO2nanorods (NR) supported Ni catalysts in a fixed-bed coaxial dielectric barrier discharge (DBD) reactor. This study individually examined the catalyst support, packing material, and 10 wt% Ni-CeO2NR catalyst under pure thermal and plasma-assisted thermal DRM environments to explore the plasma-thermal synergy. Support and packing material displayed no discernible reactivity under thermal DRM within 450 °C; however, the catalyst exhibited reactivity beginning around 350 °C. Alternatively, plasma-assisted DRM experiments revealed a distinct reaction occurrence at significantly lower temperatures across all sample types. Introducing plasma demonstrated a significant enhancement in CH4conversion compared to CO2conversion. The 10 wt% Ni-CeO2NR catalyst in plasma-assisted DRM testing showed increasing conversions of CH4and CO2with rising temperatures, peaking at 52.1 % and 46.1 %, respectively, at 450 °C. The catalyst’s improved performance in the plasma environment can be attributed to the enhanced metal-support interaction between NiO and the CeO2NR support, a consequence of the rich surface oxygen vacancy concentration. However, this increase in conversion was accompanied by an escalation in carbon deposition. Considering contributions from the thermal DRM process, the optimal operating temperature was determined as 350 °C. Increasing plasma power at this temperature led to enhanced conversion. However, beyond a threshold of 23.8 W power, the reaction path altered, resulting in reduced syngas output. Increasing the CH4:CO2feed gas flow ratio, while maintaining constant plasma power and temperature, elevated H2/CO generation. Moreover, increasing the total flow rate under identical conditions, with a constant feed gas flow ratio, reduced both conversions due to decreased chemical residence time. Consequently, under a constant feed gas ratio, a higher syngas yield is achievable with lower overall flow rates.