Bernd Platzer

Liquid phase hydrogenation of p-nitrotoluene in microchannel reactors

The hydrogenation of p-nitrotoluol to p-toluidin was done both in a fixed bed reactor and in a microchannel reactor made of a stack of microstructured aluminum wafers. Two procedures for the deposition of the catalytic active component palladium on the microstructured aluminum wafers are described. The hydrogenation results are discussed. Advantages and drawbacks of both reactor types are shown.

Konzepte zur Simulation katalysierter Reaktionen in Mikroreaktoren mit Mesoporen im Wandbereich

Conducting reactions in microreactors requires not only optimal operating conditions but also a favourable geometric design of the equipment used. The necessary information can be deduced from calculations of concentration and temperature fields. Although the mesopores encountered in microreactors are highly regular, size differences between channel and pore make a closed numerical calculation of the total fluid space neither meaningful nor possible. A system of effective kinetics which considers mass flows subject to exchange processes via the pore openings is therefore introduced for isothermal reactions. Numerical solutions involve enormous number crunching effort and also have the drawback that the influence of individual parameters only becomes clear after extensive variant calculations. A detailed presentation of borderline cases amenable to analytical treatment and of solutions obtainable with the aid of other models (such as the use of oxygen transfer coefficients or pore efficiencies) is therefore also provided.

Concepts for the Simulation of Wall‐Catalyzed Reactions in Microchannel Reactors with Mesopores in the Wall Region

The realization of reactions in microchannel reactors demands apart from optimal process conditions also a useful geometric layout of the apparatus. Information about the usefulness of the geometry is available through the simulation of the concentrations and the temperature field and their evaluation. Although the mesopores used in microchannel reactors are very regular, the discrepancies between channel and pore dimensions are very large and so, a simultaneous numerical calculation of the entire reactor is neither meaningful nor possible. Therefore, in this paper, an effective kinetics for isothermal reactions considering the diffusional mass flow through the pore mouth is introduced. Still, numerical calculations are very expensive and have the disadvantage that the influence of the individual parameters is seen only by a lot of calculations with changed parameters. Thats why a survey of cases with analytical solutions and with other concepts (using mass transfer coefficients, effectiveness factors, etc.) is given, too.

Methodology for EBSILON simulation studies of on-site generation CHP systems for data centre

The use of information technology services is increasing and causes a rising energy demand of data centres. In order to cover the requirements linked to this effect and respond to the energetic and environmental goals, fossil fuels need to be replaced by renewable energy sources, and methods to increase the efficiency of the processes have to be developed. Regarding the energy supply of data centres, the complex integration of different energy systems into the technical infrastructure of the data centres is challenging. Within the RenewIT project [1], fourteen thermal and electrical power supply concepts for data centres have been investigated [2]. Regarding intermediate results of the project, the four concepts with combined heat and power production (CHP) provide the most promising solutions. One of the concepts with CHP, the system biogas-fed solid oxide fuel cell (SOFC), is presented to show the methodology of modelling and simulating the CHP subsystem including non-series products with EBSILON [3]. The complex part load behaviour of the subsystem is identified and the information is transferred into TRNSYS [4] to increase data processing and minimize computing time.