Sorption-Enhanced CO2 Hydrogenation to Methanol under Dynamic Reaction Conditions

高效的碳捕获和利用（CCU）是可持续碳中和经济的关键要素。目前的二氧化碳分离技术（即变压吸附）以及可再生能源的动态可用性要求开发能够在反应物浓度和可再生能源可用性的动态变化中运行的工艺。在这个项目中，我们研究了在吸附剂的反应性（周期性）再生过程中，二氧化碳捕获和绿色H2加氢制甲醇的结合，以利用二氧化碳作为生产甲醇的丰富碳源。为了取得成功，需要在低温下动态操作和对甲醇的高选择性，以达到足够的甲醇收率。与多步反应系统相比，该集成系统中，二氧化碳被同一催化剂在吸附温度（或仅略微提高温度）下捕获和转化，从而减少了总能量输入。在项目的第一阶段，二氧化碳捕获/转换概念证明是可行的。它基于一种催化剂，该催化剂包括用于CO2吸附的胺功能化多孔固体和用于CO2加氢成甲醇的贵金属。在第二阶段，CO2与胺基的相互作用和与贵金属颗粒的局部接近将被增强，以增加CO2的结合，从而提高与甲醇的反应速率。应用微动力学模型和多尺度反应器模拟研究反应机理，为合理开发提高甲醇产率所需的新型催化材料提供依据。

Efficient carbon capture and utilization (CCU) is a key element for a sustainable carbon neutral economy. The current CO2 separation technology (i.e., pressure swing adsorption) as well as the dynamic availability of renewable energy requires the development of processes able to operate during dynamic changes in the reactant concentrations and in the availability of renewable energy. In this project we investigate the combination of CO2 capture followed by hydrogenation to methanol with green H2 during a reactive (periodic) regeneration of the sorbent in order to utilize CO2 as abundant carbon source for the production of methanol. For being successful, dynamic operation at low temperatures and high selectivity to methanol are required to reach a sufficient methanol yield. The integrated system, in which CO2 is captured and converted by the same catalyst at the sorption temperature (or only slightly enhanced temperatures) allows to reduce the overall energy input compared to a multistep reaction system. In phase I of the project, the CO2 capture/conversion concept was shown to be feasible. It is based on a catalyst comprising an amine functionalized porous solid for CO2 sorption and a noble metal for the hydrogenation of CO2 to methanol. In phase II, the interaction of CO2 with the amine groups and the local proximity to the noble metal particles will be enhanced in order to increase the binding of CO2 and hence the rate of the reaction to MeOH. Microkinetic modeling and multiscale reactor simulations will be applied study the reaction mechanism, which will enable the rational development of novel catalytic materials required for enhancing the MeOH yield.