Isothermal conditions and a chemical-kinetics-limited rate should be maintained when measuring the reaction rates of gases on solid catalysts. However, in highly exothermic reactions─such as the Sabatier reaction─temperature variations within the catalyst bed make it challenging to achieve isothermality. In this study, temperature changes in a Ni/ZrO₂ catalyst bed were minimized using α-Al₂O₃ diluent and high gas hourly space velocities (GHSVs) to achieve low feed gas conversion (differential conditions: 0.9 MPa; 523–873 K; GHSV = 7600–30,000 L/h/g cat). The temperature profile within the catalyst bed was obtained by coupling a previously reported kinetic model with three-dimensional computational fluid dynamics (CFD) simulations. Experiments were also conducted under integral conditions at low GHSVs, resulting in high conversion rates and heat release. CFD simulations accurately reproduced the experimental feed gas conversion and temperature, suggesting that the CFD-simulation-guided kinetic parameters appropriately predicted the methanation characteristics at practically relevant high conversion rates.

中文翻译：

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差分和整体固定床反应器中的镍/氧化锆催化 CO2 甲烷化：实验和计算流体动力学研究


在测量气体在固体催化剂上的反应速率时，应保持等温条件和化学动力学限制速率。然而，在高度放热的反应（例如 Sabatier 反应）中，催化剂床内的温度变化使得实现等温性变得具有挑战性。在本研究中，使用 α-Al₂O₃ 稀释剂和高气体每小时空速 （GHSV） 将 Ni/ZrO₂ 催化剂床中的温度变化降至最低，以实现低原料气转化率（差值条件：0.9 MPa;523–873 K;GHSV = 7600–30,000 L/h/g 猫）。催化剂床内的温度曲线是通过将先前报道的动力学模型与三维计算流体动力学 （CFD） 模拟相结合获得的。实验还在低 GHSV 的积分条件下进行，导致高转化率和热释放。CFD 模拟准确地再现了实验原料气转化率和温度，表明 CFD 模拟引导的动力学参数在实际相关的高转化率下适当地预测了甲烷化特性。