Rh负载的泡沫独石上甲烷部分氧化的基元反应动力学模拟

Simulation of Partial Oxidation of Methane on the Rhodium Coated Foam Monolith Based on the Elementary Kinetics

Rh负载的泡沫独石催化剂上进行的甲烷催化部分氧化反应,能够在自热、毫秒级接触的条件下达到接近平衡的转化率和选择性。采用CH4在Rh催化剂上发生部分氧化反应的基元反应动力学网络结合平推流模型,进行了一维的反应流模拟,揭示了毫秒级催化反应的反应历程。CH4/O2摩尔比在1.7～2.3,外界温度550～800℃的范围内,模拟结果和实验结果能够很好地吻合。模拟不仅给出了催化剂床层内气相和表面物种的变化情况,还揭示了催化剂有效内表面积和甲烷吸附能力对反应的影响,发现一定程度下有效内表面积的增加和甲烷吸附能力的增强,能够大幅度地提高反应的转化率和选择性。

The Rhodium-impregnated foam monolith catalyst was applied to the catalytic partial oxidation of methane （CPOM） to syngas. Under the auto-thermal condition with milliseconds contact time, the reaction conversion and selectivity can almost reach their equilibrium states. The one-dimensional simulation based on the plug flow reactor （PFR） model with detailed elementary kinetics was carried out to explain the process of the millisecond catalytic reaction. In the range of CH4/O2 from 1.7 to 2.3 and environmental temperature from 550℃ to 800℃, the model predictions have good agreement with the experimental results in terms of the reaction conversion and selectivity. Detailed information, such as the profiles of the composition in the gas phase and the absorbed species on the catalyst was revealed by simulations. The simulations also indicate that the conversion of methane and selectivity to H2 and CO for this process can be greatly improved with the increase of the effective internal surface area of the catalyst and the adsorption capability of methane on the catalyst.