Utilizing volatile renewable energy sources (e.g., solar, wind) for chemical production systems requires a deeper understanding of their dynamic operation modes. Taking the example of a methanation reactor in the context of power-togas applications, a dynamic optimization approach is used to identify control trajectories for a time optimal reactor start-up avoiding distinct hot spot formation. For the optimization, we develop a dynamic, two-dimensional model of a fixed-bed tube reactor for carbon dioxide methanation which is based on the reaction scheme of the underlying exothermic Sabatier reaction mechanism. While controlling dynamic hot spot formation inside the catalyst bed, we prove the applicability of our methodology and investigate the feasibility of dynamic carbon dioxide methanation.

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Innovative reactor concepts show evidence to significantly improve the reaction performance in comparison to conventional reactor systems. To evaluate the reactor concepts, experimental investigation of the process behavior is indispensable. In this contribution, a reactor tandem comprising a repeatedly operated semibatch reactor (RSBR) followed by a continuously stirred tank reactor (CSTR) is analyzed for the hydroformylation of 1-dodecene. This reactor tandem was suggested by N. M. Kaiser et al. [Ind. Eng. Chem. Res. 2017, 56, 11507–11518] to increase the selectivity toward the linear aldehyde at high conversion levels of 1-dodecene. An additional degree of freedom is gained because of the combined utilization of a batchwise and continuously operated reactor. By using a dynamic process model for planning of the experiments, comparability is ensured with studies of a single CSTR from literature. The experiments confirm an increase in conversion and target product yield applying the RSBR + CSTR tandem, so that up to 90% selectivity is achieved with closed byproduct recycle.