Sorption-Enhanced CO2 Hydrogenation to Methanol under Dynamic Reaction Conditions

高效的碳捕获和利用(CCU)是可持续碳中性经济的关键要素。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获得性要求开发能够在反应物浓度和可再生能源可获得性发生动态变化时运行的过程。在这个项目中，我们研究了在反应性(周期性)再生过程中，二氧化碳捕获和加氢合成甲醇的组合，以便利用二氧化碳作为丰富的碳源来生产甲醇。为了获得成功，需要低温下的动态操作和对甲醇的高选择性来达到足够的甲醇产率。与多步反应系统相比，集成系统在吸附温度(或仅略有升高的温度)下由相同的催化剂捕获和转化二氧化碳，从而减少了总的能量输入。在该项目的第一阶段，二氧化碳捕获/转化概念被证明是可行的。它是基于一种催化剂，该催化剂包含用于吸附二氧化碳的胺功能化多孔固体和用于将二氧化碳加氢为甲醇的贵金属。在第二阶段，CO2与胺基团的相互作用和与贵金属颗粒的局部亲和性将得到加强，以增加CO2的结合，从而加快反应与甲醇的反应速度。微观动力学建模和多尺度反应器模拟将用于研究反应机理，这将使合理开发提高甲醇产率所需的新型催化材料成为可能。

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.