CHAIR OF

THERMAL PROCESS ENGINEERING

A new International Max Planck Research School (IMPRS) titled Systems and Process Engineering for a Sustainable Chemical Production (SysProSus) has been approved by the Max Planck Society and our University. It will start in January 2025 with a First Call for excellent PhD candidates. For description and conditions of the school and the call see: https://www.mpi-magdeburg.mpg.de/imprs.

There is the chance to pursue a Ph.D. in our group Transport in Porous Media under supervision of Dr.-Ing. Nicole-Vorhauer in the field of plastic degradation. Conversion of plastic waste into valuable intermediates or recycling into more sustainable, i.e., biodegradable, products requires development of novel energy efficient technologies. A possible route could be biological conversion using microorganisms, provided that competitive reactor concepts can be developed. Such a development requires a strong fundamental scientific base, for which we aim at powerful mathematical models (e.g., https://dx.doi.org/10.2139/ssrn.4966212).

A pore network model was developed for the simulation of biofilm growth inside a porous substrate within the TPM research group, which forms the foundation for further studies in the field.

In the frame of IMPRS SysProSus we are looking for an outstanding PhD candidate interested in mathematical modeling. While further information can be found here https://www.mpi-magdeburg.mpg.de/4704267/research-SysProSus, a suitable application should be submitted here https://www.mpi-magdeburg.mpg.de/imprs-application.

Also check an open position within this research school about Cofluidization of particles of different sizes and shapes under supersion of Prof. Dr.Ing. Evangelos Tsotsas here.

As part of the „Kinder-Uni“ series at OVGU, Dr.-Ing. Nicole Vorhauer-Huget and her team have given a special lecture for children in the age of 8 to 12 years. The topic was related to her research in the CRC/TRR 287 BULK-REACTION, namely microwave heating, but with a special focus on Christmas.

The children were very excited to see an experiment with a large piece of chocolate, demonstrating uneven heating inside household microwave apparatuses. The children further participated in the lecture by trying to reproduce high-frequency waves with their scarfs and ribbons.

Besides that, the children learned why process engineering and conversion of raw materials is necessary for the production of Christmas presents like a chocolate or Christmas wrapping paper.

At the 23rd International Drying Symposium (IDS 2024), which took place from 22 to 25 November 2024 in Wuxi, China, Dr.-Ing. Nicole Vorhauer-Huget has obtained the Young Drying Scientist Award, in recognition of her excellent contribution to the advancement of drying science and technology.

Prof. Arun S. Mujumdar, McGill University (Canada) and Honorary Chairman of the IDS 2024, presents the Award to Dr.-Ing. Nicole Vorhauer-Huget (© TPM research group).

Dasika Prabhat Sourya, Pardha S. Gurugubelli, Supriya Bhaskaran, Nicole Vorhauer-Huget,  Evangelos Tsotsas, Vikranth Kumar Surasani

https://doi.org/10.1016/j.ijhydene.2024.10.340

The optimization of Polymer Electrolyte Membrane (PEM) electrolyzers necessitates an intimate knowledge of the oxygen flows within the anodic porous transport layers (PTLs) to determine any possible reduction in performance. In this field, as experimental studies are cumbersome and expensive, numerical modeling has arisen as a viable alternative for studying the oxygen transport within the Anodic PTLs of a PEM electrolyzer. Amongst the various numerical modeling techniques, the Lattice Boltzmann Method (LBM) is gaining prominence for its effectiveness in analyzing fluid transport within porous media due to its mesoscopic nature and ease of implementation. This study utilizes the Shan-Chen LBM methodology to model the flow of oxygen within the Anodic PTL of a PEM electrolyzer and compares it against the Volume-of-Fluid-based Continuum Model. The results show that LBM can not only replicate the experimental studies accurately, but can also maintain its high accuracy at progressively shrinking length scales of PTLs, even at length scales where the VoF-based Continuum Model would run into accuracy issues. The high accuracy of the LBM model, combined with the simplicity of the LB algorithm makes LBM a powerful technique for simulating the microfluidic flows such as the flow of oxygen within the Anodic PTL of a PEM electrolyzer.

Felix Faber, Nicole Vorhauer-Huget, Maximilian Thomik, Sebastian Gruber, Petra Foerst, Evangelos Tsotsas

https://doi.org/10.1080/07373937.2024.2407062

This study presents a pore network (PN) model with transient heat transfer and quasi-steady transitional vapor transport that is for the first time applied to irregular porous structures that are obtained by reconstruction of X-ray tomography image data. In contrast to previous studies, the irregular pores are not approximated by spheres but implemented in their original shape. Secondly, instead of assuming cylindrical throats as pore connections, the actual distance between pore centers as well as the pore cross sections are used for the computation of the vapor transport coefficient. The control volume elements of the computational model are matched with the cells obtained by Voronoi tessellation. The improvements have clear advantages over former approaches where the reconstructed void space is usually strongly simplified by balls and sticks confined in a regular lattice structure. A freeze-dried sample of maltodextrin DE12 with 20% (w/w) solid content is used for benchmarking the new methodology. Its morphological and thermal properties are determined by the novel PN model. The simulation results of primary freeze-drying (FD) are compared to reference cases in two ways. First, the differences in heat and mass transfer kinetics as compared to regular PNs are emphasized. Secondly, the PN simulation results are confronted with a simple literature model that neglects pore size distribution (PSD) and transient heat transfer. It is shown that already in small domains with relatively narrow PSD, the variation of the mass transfer coefficient affects the computed sublimation fluxes and yields a significant deviation from the simpler literature model. Moreover, it is revealed in this study that the structure has a significant impact on the sublimation front temperature. This is demonstrated by the comparison of FD in the irregular PN to a regular PN with almost identical PSD but different porosity. The development, verification, and benchmarking of the new PN model can be seen as an important step for studies of the structure dependence of FD.

Andrea Dernbecher, Supriya Bhaskaran, Nicole Vorhauer-Huget, Jakob Seidenbecher, Suresh Gopalkrishna, Lucas Briest, and Alba Dieguez-Alonso

http://dx.doi.org/10.1007/978-3-031-66609-4_36

This work investigates the impact of the realistic porous structure of a biomass particle on the intraparticle convective transport. To this end, the porous structure of a biomass particle pyrolyzed at 300°C as characterized with X-ray microtomography and a realistic reconstruction of the microstructure was used for pore-resolved computational fluid dynamics (CFD) simulations of the flow. Based on these simulation results, local interfacial heat transfer coefficients in the pores were evaluated. This is a first step to derive macroscopic effective parameters that describe the intraparticle transport taking into account the complex anisotropic microstructure and morphology of the particle, as well as its evolution during the pyrolytic conversion process.