Zhang Xizhe, Cheng Nuo, Zhang Yuhan, Tian Sicong, Han Lujia
Engineering Laboratory for AgroBiomass Recycling & Valorizing, College of Engineering, China Agricultural University, Beijing, 100083, P. R. China.
ChemSusChem. 2024 Dec 6;17(23):e202400856. doi: 10.1002/cssc.202400856. Epub 2024 Aug 6.
Chemical looping reforming of methane (CLRM) with Fe-based oxygen carriers is widely acknowledged as an environmentally friendly and cost-effective approach for syngas production, however, sintering-caused deactivate of oxygen carriers at elevated temperatures of above 900 °C is a longstanding issue restricting the development of CLRM. Here, in order to reduce the reaction temperature without compromising the chemical-looping CH conversion efficiency, we proposed a novel operation scheme of CLRM by manipulating the reaction pressure to shift the equilibrium of CH partial oxidation towards the forward direction based on the Le Chatelier's principle. The results from thermodynamic simulations showed that, at a fixed reaction temperature, the reduction in pressure led to the increase in CH conversion, H and CO selectivity, as well as carbon deposition rate of all investigated oxygen carriers. The pressure-negative CLRM with FeO, FeO and MgFeO could reduce the reaction temperature to below 700 °C on the premise of a satisfactory CLRM performance. In a comprehensive consideration of the CLRM performance, energy consumption, and CH requirement, NiFeO was the Fe-based OCs best available for pressure-negative CLRM, especially for an excellent syngas yield of 23.08 mmol/g. This study offered a new strategy to address sintering-caused deactivation of materials in chemical looping from the reaction thermodynamics point of view.
以铁基氧载体进行甲烷化学链重整（CLRM）被广泛认为是一种生产合成气的环保且具有成本效益的方法，然而，在900 °C以上的高温下，氧载体因烧结而失活是限制CLRM发展的一个长期存在的问题。在此，为了在不降低化学链CH转化效率的情况下降低反应温度，我们基于勒夏特列原理，通过控制反应压力来使CH部分氧化的平衡向正向移动，从而提出了一种CLRM的新型操作方案。热力学模拟结果表明，在固定反应温度下，压力降低导致CH转化率、H和CO选择性以及所有研究的氧载体的积碳速率增加。采用FeO、FeO和MgFeO的负压CLRM可以在获得令人满意的CLRM性能的前提下将反应温度降低至700 °C以下。综合考虑CLRM性能、能耗和CH需求，NiFeO是最适合负压CLRM的铁基氧载体，尤其是其合成气产率高达23.08 mmol/g。本研究从反应热力学角度为解决化学链中材料烧结失活问题提供了一种新策略。
