Abstract: The stability of Rh-coated foam monolith with different pore sizes for catalytic partial oxidation of methane was investigated. The results showed that 0.3%(w) Rh coated foam with 3 mm in length and 0.32 mm in pore size had similar initial catalytic performances with the foam at 10 mm in length and 0.576 mm in pore size, but its deactivation rate was only 1/5 of the latter. The CFD modeling coupled with detailed elementary kinetics was successfully established and applied to predict the species concentration and surface temperature profiles within the two catalysts above. The foam with a smaller pore size, which had a higher catalytic surface area per unit volume, increased the rates of exothermic oxidation reaction and endothermic reforming reaction by 1.1 and 3.7 times, respectively. As a consequence, more steam reforming reaction occurred and its hot-spot temperature was 171℃ lower than the foam with a larger pore size. The hot-spot temperature of the foam with 0.576 mm in pore size was decreased by 235℃ after increasing its catalytic surface area per unit volume by 8 times.

Key words: catalytic partial oxidation, Rh, foam monolith, stability, CFD, elementary kinetics

摘要： 研究了不同孔径的Rh泡沫独石催化剂在甲烷部分氧化过程中的稳定性. 结果表明，长度3 mm、Rh负载量0.3%(w)、孔径0.32 mm的泡沫独石催化剂与长度10 mm、Rh负载量0.3%(w)、孔径0.576 mm的泡沫独石催化剂具有相同的初始催化性能，但小孔径催化剂的失活速率仅为大孔的1/5. 建立了耦合基元反应动力学的计算流体力学模拟平台，模拟了所用的2种催化剂的内部浓度场和催化剂表面温度. 小孔径催化剂具有更大的单位体积催化表面积，使放热氧化反应的反应速率提高了1.1倍，而将吸热的重整反应速率提高了3.7倍. 小孔径催化剂强化催化剂床层内蒸汽重整反应，其热点温度比大孔径催化剂低171℃. 孔径0.576 mm的催化剂将单位体积催化表面积增大8倍，能使催化剂的热点温度降低235℃.

关键词: 催化部分氧化, Rh, 泡沫独石, 稳定性, 计算流体力学, 基元反应动力学