Jens Bremer

Clausthal University of Technology | TUC · Institute of Chemical and Electrochemical Engineering

With the increasing need to utilize carbon dioxide, fixed-bed reactors for catalytic hydrogenation will become a decisive element for modern chemicals and energy carrier production. In this context, the resilience and flexibility to changing operating conditions become major objectives for the design and operation of real industrial-scale reactors....

CO2 methanation is often performed on Ni/Al2O3 catalysts, which can suffer from mass transport limitations and, therefore, decreased efficiency. Here we show the application of a hierarchically porous Ni/Al2O3 catalyst for methanation of CO2. The material has a well-defined and connected meso- and macropore structure with a total porosity of 78%. T...

Power-to-Methane is a concept for energy storage harvested from renewable sources, for instance solar and wind power. A flexible operation of catalytic fixed-bed methanation reactors, according to the availability of energy, eliminates the need to store intermediate reactants in large buffer units. This requires reliable heat management, as the hea...

Heterogeneous catalytic reactions are essential for future CO2-based process routes, but are, however, sensitive to dynamic perturbations. To incorporate these processes into existing production networks, increased flexibility under different operating loads is necessary. One prominent example of a CO2-based process is methanation using H2 as a bas...

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-to-gas applications, a dynamic optimization approach is used to identify control trajectories for a time optimal reactor...

Power‐to‐methane (PtM) offers an efficient opportunity for surplus renewable energy storage, but heat management is a major challenge for conducting the highly exothermic methanation reaction. To address this challenge, this study presents the first successful demonstration of core‐shell catalyst pellets in a pilot‐scale reactor for CO 2 methanatio...

In the present contribution, the historical development of dimensionless numbers describing axial mixing effects in chemical reactors is analyzed. While the Bodenstein number has become established in Europe, the American literature often uses the Péclet number for this purpose. A journey through the historical reaction engineering literature shows...

Die Zirkularität von Stoffströmen, die Nachhaltigkeit, vor allem die Nutzung biogener Rohstoffe, sowie die Ressourcen‐ und Energiesicherheit sind seit Jahren wichtige Ziele. Ob in der Reaktions‐ oder der Trenntechnik, alle Bereiche der technischen Chemie profitieren von grundlegenden Stützpfeilern. Mit den darin enthaltenen methodischen Ansätzen la...

Catalyst research is concerned with synthesizing increasingly active materials, leading to safety issues at reactor scale, unless the reaction heat release is controllable. Computational studies predict, that core-shell pellets, with catalytically active core and inert shell, are beneficial for this purpose, compared to established concepts, such a...

There is considerable motivation in the catalysis community and chemical industry to envision a future where rational catalyst design and targeted chemical process optimization become standard. Achieving this goal for heterogeneous catalysis requires a cultural shift centered around effective research data management. The core elements of modern ca...

Fixed-bed reactors employed within Power-to-X technologies are expected to be subject to volatile process feeds, in order to minimize intermediate buffer or storage systems. In this context, catalyst particles with an inert shell have proven suitable to prevent reactor runaway and severe temperature excursion at various loads and during load-change...

Many research activities focus on load-flexible fixed-bed reactors in the context of Power-to-X concepts. One of the main issues is the occurrence of hazardous temperature excursions in steady state and during dynamic load changes. The dilution of the catalytically active fixed-bed with inert particles and the use of catalyst particles with active...

The design of fixed-bed reactors has gained interest in the light of load-flexible operation. This is due to the expectation that some process feeds will be more volatile in the near future, for example, within the framework of the power-to-methane concept. In this regard, the application of an inert shell onto the catalyst particles has proven adv...

The optimization of a controlled process in a simulation without access to the model itself is a common scenario and very relevant to many chemical engineering applications. A general approach is to apply a black-box optimization algorithm to a parameterized control scheme. The success then depends on the quality of the parametrization that should...

Fixed-bed reactors can effectively perform chemical reactions with high space-time yields and are, therefore, an essential part of many processes in the chemical industry. With the increasing integration of volatile renewable energies, these processes, and thus also the installed reactors, will operate at different loads more often. Using the examp...

Published by The Royal Society of Chemistry.

Published by The Royal Society of Chemistry.

Published by The Royal Society of Chemistry.

Published by The Royal Society of Chemistry.

Published by The Royal Society of Chemistry.

Published by The Royal Society of Chemistry.

Many computational difficulties in dealing with chemical process models often result from spatially distributed states as well as nonlinear correlations (e.g., for transport coefficients or reaction kinetics). Surrogate models with sufficient accuracy represent one remedy to this problem. Featuring a lower number of states, model order reduction (M...

Transition to renewable energy sources requires energy storing technologies like Power-to-Gas approaches to counter their inherent volatile nature. As a consequence, dynamic reactor operation becomes necessary. The exothermic carbon dioxide methanation is one key conversion step within the Power-to-Gas process, which requires careful reactor temper...

Dealing with dynamic, nonlinear, large-scale process models often leads to many computational difficulties. One remedy to this problem is the replacement of these large-scale models by surrogate models with sufficient accuracy. Model order reduction (MOR) generates considerably less complex models featuring a lower number of states, leading to fast...