Modeling the CO2 capture and in situ conversion to CH4 on dual function Ru-Na2CO3/Al2O3 catalyst
Modeling the CO2 capture and in situ conversion to CH4 on dual function Ru-Na2CO3/Al2O3 catalyst
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DOI：
10.1016/j.jcou.2020.101351
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发表时间：
2020-12-01
影响因子：
7.7
通讯作者：
Gonzalez-Velasco, Juan R.
中科院分区：
文献类型：
--
作者：
Bermejo-Lopez, Alejandro;Pereda-Ayo, Benat;Gonzalez-Velasco, Juan R.
提出了一个描述在4% Ru-10%Na2CO3/Al2O3催化剂上CO2吸附和原位加氢成CH4的动力学模型。考虑了轴向分散的一维等温非均质塞流反应器模型。通过对实验数据的分析，推导了反应网络和动力学方程。分子模拟包括CO2和H2O在同一吸附位点上的竞争吸附。在CO2储存期间，CO2吸附在Na2O物质上形成Na2CO3。或者，CO2也可以吸附在NaOH物质上，释放出H2O到气相，H2O可以进一步吸附到位于下游的自由吸附位点上。为了拟合实验数据，需要考虑不稳定碳酸氢盐的形成。在CO2加氢过程中，吸附的碳酸盐被H-2催化分解。然后通过Sabatier反应生成CH4，生成的H2O与再生的吸附位点相互作用。在较宽的反应物浓度和温度范围内（250 ~ 400℃），该模型准确预测了CO2储存和加氢循环过程中CO2、CH4和H2O的时间演变，从而对双功能材料的过程机理和动力学有了更深入的了解。
A dynamic kinetic model is proposed to describe the CO2 adsorption and in situ hydrogenation to CH4 on a 4% Ru-10%Na2CO3/Al2O3 catalyst. One dimensional isothermal heterogeneous plug flow reactor model with axial dispersion is considered. The reaction network and kinetic equations are deduced from experimental data analysis. The molecular modeling includes competitive adsorption of CO2 and H2O on same adsorption site. During CO2 storage period, CO2 is adsorbed onto Na2O species to form Na2CO3. Alternatively, CO2 can be also adsorbed onto NaOH species releasing H2O to the gas phase, which can further be adsorbed onto free adsorption sites located downstream. It was needed to consider formation of unstable bicarbonates to fit the experimental data. During CO2 hydrogenation step, adsorbed carbonates are decomposed, promoted by the presence of H-2. CH4 is then formed through the Sabatier's reaction and the as-formed H2O interacts with regenerated adsorption sites. Temporal evolution of CO2, CH4 and H2O during CO2 storage and hydrogenation cycles is accurately predicted by the model, for a wide range of reactant concentrations and temperature (250 400 degrees C), gaining understanding on mechanisms and dynamics of the process on dual function materials.