Sigrid Wolf, Michaela Roschger, Boštjan Genorio, Daniel Garstenauer and Viktor Hacker
The development of highly efficient, stable, and selective non-precious-metal catalysts for the oxygen reduction reaction (ORR) in alkaline fuel cell applications is essential. A novel nanocomposite of zinc- and cerium-modified cobalt-manganese oxide on reduced graphene oxide mixed with Vulcan carbon (ZnCe-CMO/rGO-VC) was prepared. Physicochemical characterization reveals uniform distribution of nanoparticles strongly anchored on the carbon support resulting in a high specific surface area with abundant active sites. Electrochemical analyses demonstrate a high selectivity in the presence of ethanol compared to commercial Pt/C and excellent ORR activity and stability with a limiting current density of −3.07 mA cm–2, onset and half-wave potentials of 0.91 and 0.83 V vs reversible hydrogen reference electrode (RHE), respectively, a high electron transfer number, and an outstanding stability of 91%. Such a catalyst could be an efficient and cost-effective alternative to modern noble-metal ORR catalysts in alkaline media.
ACS Omega, 2023
http://doi.org/10.1021/acsomega.3c00615
Lab of Tomorrow Tunisia – UNIDO-BMK Workshop, 12–14 March 2023 in Tunis.
Prof. Merit Bodner and Prof. Viktor Hacker met with more than 80 Tunisian and Austrian stakeholders in a technical workshop on green hydrogen and water-related impacts.
This trip to Tunisia was the first time that UNIDO's cooperation under the Global Programme for Hydrogen in Industry, on the one hand, and the deepening under the Lab of Tomorrow process with the Austrian Development Agency and the German GIZ, on the other, were carried out together.
Thematically, during the two-day UNIDO BMK workshop, the topic of green hydrogen and, as a special topic, the water issues associated with electrolysis (desalination, wastewater treatment, competition for use, etc.) could be very well illuminated from several sides between Austrian and Tunisian representatives: Austria's and Tunisia's strategic vision on renewable energies and hydrogen, UNIDO's expertise, the scientific perspective, the private sector's perspective and the expertise of Austrian companies specifically on the topic of water.
www.unido.org/news/tunisia-austria-and-unido-advance-long-term-collaboration-green-hydrogen
Die Eröffnung des neuen MINKT-Labors der TU Graz, indem Kinder und Jugendliche in die Welt der Wissenschaft eintauchen können, fand am 10. März 2023 statt. Das Institut für Chemische Verfahrenstechnik und Umwelttechnik ist mit einer Station über den Taylor-Couette Disc Contactor (TCDC) und einem kleinen wasserstoffbetriebenen Fahrzeug vertreten. Am TCDC werden Trennungsprozesse von Flüssigkeiten anhand von unterschiedlich gefärbten Flüssigkeiten anschaulich erklärt. Mit dem kleinen Wasserstofffahrzeug können Kinder und Jugendliche auf spielerische Weise etwas über die Verwendung von Wasserstoff in einer Brennstoffzelle und damit über die Nutzung alternativer Energien lernen.
Maša Hren, Damjan Makuc, Janez Plavec, Michaela Roschger, Viktor Hacker, Boštjan Genorio, Mojca Božič and Selestina Gorgieva
In this work, fully polysaccharide based membranes were presented as self-standing, solid polyelectrolytes for application in anion exchange membrane fuel cells (AEMFCs). For this purpose, cellulose nanofibrils (CNFs) were modified successfully with an organosilane reagent, resulting in quaternized CNFs (CNF (D)), as shown by Fourier Transform Infrared Spectroscopy (FTIR), Carbon-13 (C13) nuclear magnetic resonance (13C NMR), Thermogravimetric Analysis (TGA)/Differential Scanning Calorimetry (DSC), and ζ-potential measurements. Both the neat (CNF) and CNF(D) particles were incorporated in situ into the chitosan (CS) membrane during the solvent casting process, resulting in composite membranes that were studied extensively for morphology, potassium hydroxide (KOH) uptake and swelling ratio, ethanol (EtOH) permeability, mechanical properties, ionic conductivity, and cell performance. The results showed higher Young’s modulus (119%), tensile strength (91%), ion exchange capacity (177%), and ionic conductivity (33%) of the CS-based membranes compared to the commercial Fumatech membrane. The addition of CNF filler improved the thermal stability of the CS membranes and reduced the overall mass loss. The CNF (D) filler provided the lowest (4.23 × 10−5 cm2 s−1) EtOH permeability of the respective membrane, which is in the same range as that of the commercial membrane (3.47 × 10−5 cm2s−1). The most significant improvement (~78%) in power density at 80 °C was observed for the CS membrane with neat CNF compared to the commercial Fumatech membrane (62.4 mW cm−2 vs. 35.1 mW cm−2). Fuel cell tests showed that all CS-based anion exchange membranes (AEMs) exhibited higher maximum power densities than the commercial AEMs at 25 °C and 60 °C with humidified or non-humidified oxygen, demonstrating their potential for low-temperature direct ethanol fuel cell (DEFC) applications.
Polymers, 2023
DOI: 10.3390/polym15051146
Niklas Mayr, Michael Haring, and Thomas Wallek
A continuous fractional component (CFC) approach increases the probability of particle swaps in the context of vapor-liquid equilibrium simulations using the Gibbs ensemble Monte Carlo algorithm. Two variants of the CFC approach are compared for simulations of pure Lennard-Jones (LJ) fluids and binary LJ mixtures as examples. The details of an exemplary CFC implementation are presented. Recommendations are provided to reduce the effort required for the suggested problems.
American Journal of Physics 91, 235 (2023)
DOI: 10.1119/5.0135841
Mathias Heidinger, Eveline Kuhnert, Kurt Mayer, Daniel Sandu, Viktor Hacker and Merit Bodner
A new method for measuring membrane degradation in polymer electrolyte fuel cells (PEFCs) is proposed. The method is based on the detection of fluoride ions in effluent water from the cathode- and anode outlet of the PEFC using photometry (PM). The fluoride emission rate (FER) is an indicator of the membrane’s state of health (SoH) and can be used to measure the chemical membrane degradation. Commercial catalyst-coated membranes (CCMs) have been tested at 80 °C and 90 °C at 30% relative humidity (RH) to investigate the reliability of the developed method for fuel cell effluent samples. To verify the measurement, a mean-difference plot was created by measuring the same data with a fluorine selective electrode. The average difference was at ±0.13 nmol h−1 cm−2, which indicates good agreement between the two methods. These new findings imply that PM is a promising method for quick and simple assessment of membrane degradation in PEM technology.
Energies 2023, 16(4), 1957
DOI: 10.3390/en16041957
Visit to our cooperation partners at the University of Maribor, Faculty of Chemistry and Chemical Engineering (UM FKKT); meeting with Dean Prof. Dr. Zdravko Kravanja.
Interessierte Unternehmen der Region erhalten die Möglichkeit sich mit Expert:innen vor Ort zu den im MOOC Digital and Green Transition vorgestellten Themen auszutauschen.
Ökopark Hartberg, 09:00 Uhr
As part of the FEM IN TECH Infoday on 13.2.2023 at Graz University of Technology, a workshop on the topic of "Environmental Technology - Recycling of Lithium-Ion Batteries" was held by the Lithium Recycling Group of CEET. Interested pupils from grade 9 upwards had the opportunity to experience environmental technology live by means of laboratory-scale experiments.
TU Graz: https://femintech.at/
Asep Samsudin and Viktor Hacker
The anion exchange membrane is one of the core components that play a crucial and inseparable role in alkaline anion exchange membrane fuel cells. Anion exchange membranes (AEMs) were prepared from quaternary ammonium poly(vinyl alcohol) (QPVA) by an electrospinning method. QPVA was used both as material for electrospun fiber mats and as filler for the inter-fiber void matrix. The objective of this work is to investigate the influence of the inter-fibers void matrix filler concentration on the properties and performance of eQPVA-x AEMs. FTIR spectra were used to identify the chemical structures of the AEMs. The primary functional groups of PVA and quaternary ammonium-based ion conducting cation were detected. The surface morphology of QPVA nanofiber mats and eQPVA-x AEMs was observed using SEM. Electrospun nanofiber structures of QPVA with an average size of 100.96 nm were observed in SEM pictures. The ion exchange capacity, swelling properties, water uptake, and OH− ions conductivity were determined to evaluate the performance of eQPVA-x AEMs. By incorporating the QPVA matrix of 5 wt.% concentration, the eQPVA-5.0 AEMs attained the highest ion exchange capacity, water uptake, swelling properties, and OH− conductivity of 0.82 mmol g−1, 25.5%, 19.9%, and 2.26 m⋅s cm−1, respectively. Electrospun QPVA AEMs have the potential to accelerate the development of alkaline anion exchange membrane fuel cells.
International Journal of Renewable Energy Development, 2023
DOI: 10.14710/ijred.2023.49909
Max Grandi, Sebastian Rohde, D.J. Liu, Bernhard Gollas, Viktor Hacker
The global effort to introduce polymer electrolyte fuel cells for clean and renewable energy to the market is increasing the demand for high performance, robust and affordable membrane electrode assemblies (MEAs). There is not yet a standard method for large scale production of MEAs, or the methods employed are generally unsatisfactory in terms of quality and performance. A large number of published data of newly developed catalyst and electrolyte materials, claim to improve the state of the art, but are often not fully comparable due to different experimental studies and experimental designs. This article summarizes the trends in material developments and emerging MEA-manufacturing techniques. The materials and techniques are systematically compared in terms of cell performance and scalability. Current and future scientific challenges are identified and analysed based on published findings over the past five years. Finally, the results of the cited papers have been quantitatively compared to each other and to the internal benchmarks used in each cited work to provide a complete picture of the state of the art in PEFC MEA manufacturing.
Journal of Power Sources, 2023
DOI: 10.1016/j.apcatb.2023.122434
Sigrid Wolf, Michaela Roschger, Boštjan Genorio, Nejc Hodnik, Matija Gatalo, Francisco Ruiz-Zepeda and Viktor Hacker
The sluggish kinetics of the ethanol oxidation reaction (EOR) and the related development of low-cost, highly active and stable anode catalysts still remains the major challenge in alkaline direct ethanol fuel cells (ADEFCs). In this respect, we synthesized a PdNiBi nanocatalyst on reduced graphene oxide (rGO) via a facile synthesis method. The prepared composite catalyst was physicochemically characterized by SEM, STEM, EDX, ICP-OES and XRD to analyze the morphology, particle distribution and size, elemental composition and structure. The electrochemical activity and stability towards EOR in alkaline media were examined using the thin-film rotating disk electrode technique. The results reveal well-dispersed and strongly anchored nanoparticles on the rGO support,providing abundant active sites. The PdNiBi/rGO presents a higher EOR activity and stability compared to a commercial Pd/C ascribed to a high ECSA and synergistic effects between Pd, Ni and Bi and the rGO material. These findings suggest PdNiBi/rGO as a promising anode catalyst in ADEFC applications.
Journal of Electrochemical Science and Engineering, 2023
DOI: doi.org/10.5599/jese.1643
Fabio Blaschke, Marjan Bele, Brigitte Bitschnau, Viktor Hacker
The scope of this work was to investigate and understand the microscopic effects on the performance of the active catalytic system in the chemical looping process. The inhibiting and accelerating effects of the different materials have been extensively studied. The ZrO2 doped with MgO and Y2O3 showed a chemical inertness and the formation of a porous morphology for an enhanced cyclic stability. Testing in large-scale application indicates that supporting material with higher yttrium content in ZrO2 has an excellent performance for 100 cycles. The HT-XRD and DSC analyzes clearly show microscopic phenomena play a fundamental role in the process and correspond to the phase transition. Stabilization of the cubic/tetragonal crystal structure leads to suppression of the phase transition and exhibits highest activity. The work reveals new fundamental principles for the design of OC in chemical looping hydrogen and understanding the influence of microscopic effects on the stability of oxygen carriers.
Applied Catalysis B: Environmental, 2023
Eveline Kuhnert, Viktor Hacker, and Merit Bodner
During the past decades, a significant amount of excellent scientific results has been generated in the field of polymer electrolyte membrane water electrolysis (PEMWE). Compared to current state-of-the-art technologies, PEMWE offers the opportunity to produce green hydrogen with zero carbon emissions. However, the membrane electrode assembly (MEA), whose price is still high for a rather limited lifetime, needs further improvement in terms of performance, cost, and durability. In order to efficiently process novel materials, accelerated stress tests (ASTs) can be implemented to provoke and investigate cell ageing processes and assess failure modes under real-life conditions. In this review, the different accelerated stressors of the main components of the MEA are discussed, and recent publications of ASTs in the study of PEMWE cell durability are summarized. Furthermore, a concise review of the degradation mechanisms for the individual MEA components depicted in recent publications is presented. The different aspects identified in this review serve as a roadmap to further advance the durability of novel stack materials.
International Journal of Energy Research, 2023
DOI: 10.1155/2023/3183108
Indian PhD student Chetna Madan gives an insight into her stay as a visiting researcher at the Institute of Chemical Engineering and Environmental Technology at TU Graz.
People, TU Graz
Die Rolle von Wasserstoff im zukünftigen Energiesystem (V. Hacker). Die Energie- und Klimakrise macht eine dekarbonisierte Wirtschaft alternativlos. Wasserstoff kann als Energieträger einen wesentlichen Beitrag dazu leisten und seine chemische Anwendung in Brennstoffzellen ist bereits jetzt möglich.
Urania, Alte Technik 19-20:30 Uhr
Ankündigung https://www.urania.at/unser-angebot/kurs/Wasserstoff/I0123
Michaela Roschger, Sigrid Wolf, Kurt Mayer, Andreas Billiani, Boštjan Genorio, Selestina Gorgieva and Viktor Hacker
Determining the optimum layer thickness, for the anode and cathode, is of utmost importance for minimizing the costs of the alkaline direct ethanol fuel cell (DEFC) without lowering the electrochemical performance. In this study, the influence of layer thickness on the performance of the ethanol oxidation reaction (EOR) and oxygen reduction reaction (ORR) in an alkaline medium and resistance was investigated. The prepared gas diffusion electrodes (GDEs) were fully characterized, with scanning electron microscopy to determine the layer thickness and electrochemically in half-cell configuration. Cyclic voltammetry and polarization curve measurements were used to determine the oxidation and reduction processes of the metals, the electrochemical active surface area, and the activity towards the ORR and EOR. It was demonstrated that realistic reaction conditions can be achieved with simple and fast half-cell GDE measurements. Single cell measurements were conducted to evaluate the influence of factors, such as membrane or ethanol crossover. In addition, electrochemical impedance spectra investigation was performed to identify the effect of layer thickness on resistance. This successfully demonstrated that the optimal layer thicknesses and high maximum power density values (120 mW cm−2) were achieved with the Pt-free catalysts and membranes used.
Sustainable Energy & Fuels, 2023
DOI: 10.1039/D2SE01729F
Stoppacher B., Lonardi F., Bock S., Bele M., Bertucco A., Hacker V.
The utilization of real producer gases such as raw biogas or gasified wood for chemical looping hydrogen production implies the introduction of harmful contaminants into the process. Hydrogen sulfide represents one of the most challenging trace gases in the Reformer Steam Iron Cycle (RESC).
The aim of the present work was an in-depth investigation of steam reforming with pure methane and synthetic biogas contaminated with selective concentrations of 1, 5 and 10 ppm of hydrogen sulfide. To validate the experimental data, the fixed-bed reactor system was modelled as one‑dimensional pseudo‑homogeneous plug flow reactor by an adapted Maxted model. In a preliminary thermodynamic study, the dry equilibrium composition was determined within a deviation of 4% for SMR and 2% for synthetic biogas reforming compared to the experimental results.
The impact of hydrogen sulfide on the reactivity of the catalyst was discussed and quantified by the methane conversion. The deactivation rate and extent correlate directly to the concentration of H2S, as higher hydrogen sulfide concentrations lead to a faster deactivation and lower residual methane conversion. A comparison of the methane conversion as a function of sulfur coverage between experimental and simulated data showed good agreement. The predicted results are within <10% deviation for SMR and synthetic biogas reforming, except for sulfur coverages between 0.6 and 0.8. The temperature in the catalyst bed was monitored throughout the deactivation process to gather additional information about the reaction behavior. It was possible to visualize the shift of the reforming reaction front towards the bottom of the reactor caused by catalyst deactivation. The impact of sulfur chemisorption on the morphology of the steam reformer catalyst was analyzed by SEM/EDS and BET techniques. SEM images clearly indicated the presence of sulfur as a sort of dust on the surface of the catalyst, which was confirmed by EDS analysis with a sulfur concentration of 0.04 wt%.
Journal of Physics: Energy, 2023
DOI: 10.1088/2515-7655/acb668
CEET contributions to the MOOC "Dekarbonisierung & Nachhaltigkeitsmanagement: Der Weg zum klimaneutralen Unternehmen": https://imoox.at/course/dekarb
In kraft pulping, large quantities of biomass degradation products dissolved in the black liquor are incinerated for power generation and chemical recovery. The black liquor is, however, a promising feedstock for carboxylic acids and lignin. Efficient fractionation of black liquor can be used to isolate these compounds and recycle the pulping chemicals. The present work discusses the fractionation of industrial black liquor by a sequence of nanofiltration and bipolar membrane electrodialysis units. Nanofiltration led to retention of the majority of lignin in the retentate and to a significant concentration increase in low-molecular-weight carboxylic acids, such as formic, acetic, glycolic and lactic acids, in the permeate. Subsequent treatment with bipolar membrane electrodialysis showed the potential for simultaneous recovery of acids in the acid compartment and the pulping chemical NaOH in the base compartment. The residual lignin was completely retained by the used membranes. Diffusion of acids to the base compartment and the low current density, however, limited the yield of acids and the current efficiency. In experiments with a black liquor model solution under optimized conditions, NaOH and acid recoveries of 68–72% were achieved.
Paul Demmelmayer, Lena Steiner, Hansjörg Weber and Marlene Kienberger
Reactive liquid–liquid extraction has been widely investigated as a means of isolating carboxylic acids from fermentation broths. However, commonly applied fossil-based solvent phases should be replaced by green alternatives. In this work, we investigate a thymol-menthol-based deep eutectic solvent (tmDES) as a green alternative to the commonly applied modifier 1–octanol for the extraction of lactic acid, acetic acid, and oxalic acid from a model solution and pre-treated sweet sorghum silage press juice (pSPJ); tri–n–octylamine (TOA) was used as a reactive extractant. Additionally, NMR spectroscopy was used to detect interactions between menthol and thymol molecules, as well as among these and TOA and lactic acid. NMR measurements of tmDES revealed the existence of multiple intermolecular contacts between thymol and menthol. Furthermore, nuclear Overhauser effects (NOEs) between the tmDES, TOA, and lactic acid molecules were found. Extraction experiments showed that tmDES improves the extraction efficiency when using pSPJ as the feed phase. The maximum extraction efficiency for lactic acid increased from 35.0 ± 0.8 % to 48.7 ± 0.7 % and for acetic acid from 52.4 ± 0.2 % to 82.2 ± 0.6 % when using a tmDES instead of 1–octanol at 50 °C. Furthermore, the use of tmDES resulted in higher extraction efficiencies as compared to the use of 1–octanol at equilibrium pH values ranging from five to seven, which is a common pH range for fermentation. Besides having superior biocompatibility and extraction efficiency as compared to 1–octanol, tmDES allow carboxylic acid extraction processes to be carried out at higher pH levels.
Separation and Purification Technology, 2023
DOI: 10.1016/j.seppur.2022.123060
Spin-off Fellowships are an essential impulse to prepare the environment for future spin-offs and to accelerate the practical implementation of the research results of TU Graz. The project will develop and produce membrane electrode assemblies for fuel cells and electrolyzers using a newly developed catalyst system.
Press release (OTS Presseaussendung, 20.12.2022)
TU Graz news
Sigrid Wolf, Michaela Roschger, Boštjan Genorio, Daniel Garstenauer, Josip Radić and Viktor Hacker
Electrocatalyst development for alkaline direct ethanol fuel cells is of great importance. In this context we have designed and synthesized cerium-modified cobalt manganese oxide (Ce-CMO) spinels on Vulcan XC72R (VC) and on its mixture with reduced graphene oxide (rGO). The influence of Ce modification on the activity and stability of the oxygen reduction reaction (ORR) in absence and presence of ethanol was investigated. The physicochemical characterization of Ce-CMO/VC and Ce-CMO/rGO–VC reveals CeO2 deposition and Ce doping of the CMO for both samples and a dissimilar morphology with respect to the nature of the carbon material. The electrochemical results display an enhanced ORR performance caused by Ce modification of CMO resulting in highly stable active sites. The Ce-CMO composites outperformed the CMO/VC catalyst with an onset potential of 0.89 V vs. RHE, a limiting current density of approx. −3 mA cm−2 and a remaining current density of 91% after 3600 s at 0.4 V vs. RHE. In addition, remarkable ethanol tolerance and stability in ethanol containing electrolyte compared to the commercial Pt/C catalyst was evaluated. These outstanding properties highlight Ce-CMO/VC and Ce-CMO/rGO–VC as promising, selective and ethanol tolerant ORR catalysts in alkaline media.
RSC Advances, 2022
DOI: 10.1039/d2ra06806k
The current energy crisis could be a turbo for renewable energies. So-called "green hydrogen" plays an important role in the energy transition. It can generate, store and transport electricity highly efficiently and without greenhouse gas emissions. Green hydrogen" is not yet sufficiently available and therefore cannot replace fossil fuels in the short term, but in the long term it is seen as an important player on the road to an environmentally friendly, renewable energy system.
Interview mit Viktor Hacker (Ö1, Wissen Aktuell, 6. December 2022, 13:55)
Michaela Roschger, Sigrid Wolf, Boštjan Genorio and Viktor Hacker
In this work, the metal content of Pd85Ni10Bi5/C catalysts for the alkaline ethanol-oxidation reaction was reduced from 40 wt.% (PdNiBi/C (40/60)) to 30 wt.% (PdNiBi/C (30/70)), 20 wt.% (PdNiBi/C (20/80)) and 10 wt.% (PdNiBi/C (10/90)), while increasing performance. The synthesized catalysts were examined using physicochemical measurements and electrochemical measurements. The best performing catalysts were used to fabricate membrane electrode assemblies for carrying out single-cell tests and to determine the influence of the metal/carbon ratio of the electrode. The electrochemical surface area (695 cm2 mg−1) and activity were increased, resulting in high peak-current densities for the ethanol oxidation reaction (3.72 A mg−1) by the resulting more accessible metal particles. The electrode produced with the PdNiBi/C (30/70) catalyst reached a maximum power density of 34.8 mW mg−1 at 50 °C. This successfully demonstrated a doubling of the power density compared with the performance of the PdNiBi/C (40/60) electrode, while simultaneously reducing the costs.
Sustainability, 2022
doi.org/10.3390/su142215485
Asep Samsudin, Michaela Roschger, Sigrid Wolf and Viktor Hacker
In recent years, there has been considerable interest in anion exchange membrane fuel cells (AEMFCs) as part of fuel cell technology. Anion exchange membranes (AEMs) provide a significant contribution to the development of fuel cells, particularly in terms of performance and efficiency. Polymer composite membranes composed of quaternary ammonium poly(vinyl alcohol) (QPVA) as electrospun nanofiber mats and a combination of QPVA and poly(diallyldimethylammonium chloride) (PDDA) as interfiber voids matrix filler were prepared and characterized. The influence of various QPVA/PDDA mass ratios as matrix fillers on anion exchange membranes and alkaline fuel cells was evaluated. The structural, morphological, mechanical, and thermal properties of AEMs were characterized. To evaluate the AEMs’ performances, several measurements comprise swelling properties, ion exchange capacity (IEC), hydroxide conductivity (σ), alkaline stability, and single-cell test in fuel cells. The eQP-PDD0.5 acquired the highest hydroxide conductivity of 43.67 ms cm−1 at 80 °C. The tensile strength of the membranes rose with the incorporation of the filler matrix, with TS ranging from 23.18 to 24.95 Mpa. The peak power density and current density of 24 mW cm−2 and 131 mA cm−2 were achieved with single cells comprising eQP-PDD0.5 membrane at 57 °C.
Nanomaterials 2022, 12, 3965.
doi.org/10.3390/nano12223965
The ElektroPower project of the Institute of Chemical Engineering and Environmental Technology was awarded the Austrian Start-up Prize PHÖNIX in the category "PROTOTYPE" by the Federal Minister Martin Kocher of the Ministry of Labour and Economy (BMAW) and the Federal Minister Martin Polaschek of the Ministry of Education, Science and Research (BMBWF). In total, there were over 200 submissions and four prizes were assigned.
Merit Bodner received the Young Scientist Award 2022 for the Hydrogen Usages Pillar, organized by Hydrogen Europe Research. The award ceremony took place on the 26th of October 2022 as part of the Hydrogen Week 2022 in Brussels.
Young Scientist Award 2022 Press release
The course Chemical Engineering of biobased products, held by Marlene Kienberger and the course ´Bioethanolveredelung´ held by Georg Rudelstorfer are nominated for the ´Price for Excellence in teaching´. Both courses are on the short list for the price.
As part of the cooperation Research and Innovation Ecosystem Graz (RIE Graz), the institute was visited on the initiative of the head of Siemens Technology Austria and the head of CCT Additive Manufacturing, organized by DI Christine Schichler.
Astrid Loder, Simone Santner, Matthäus Siebenhofer, Andreas Böhm, Susanne Lux*
Direct reduction of mineral iron carbonate with hydrogen is a CO2-lean technology for the production of elemental iron from iron carbonate ore. In this study, the reaction mechanism and reaction kinetics were investigated by thermogravimetric analysis and in a fixed-bed tubular reactor. The degree of metallization increases with increasing temperature from 773 to 1023 K. At 1023 K, the degree of metallization is 93 wt%, with the remaining iron species being wüstite. The reduction proceeds via two reaction pathways: calcination of iron carbonate to wüstite with consecutive reduction of wüstite to elemental iron and direct reduction of iron carbonate to elemental iron. The reaction steps occur simultaneously. During the first hour of reaction, which corresponds to the heat-up phase, calcination of iron carbonate to wüstite adopts the dominant reaction path. Then wüstite reduction and direct iron carbonate reduction with hydrogen to elemental iron, become dominant, facilitated by the increasing porosity of the ore due to the release of CO2. Towards the end of the reduction process the remaining wüstite is reduced to elemental iron. The kinetic triplet – solid phase reaction kinetic model, activation energy and frequency factor – was determined for each reaction step. The reaction kinetics can be described by a combination of an Avrami-Erofeyev model (A3 model for iron carbonate calcination to wüstite), and reaction-order models (F2 model for the reduction of iron carbonate to elemental iron and F3 model for the reduction of wüstite to elemental iron).
Chemical Engineering Research and Design 188 (2022) 575-589
https://doi.org/10.1016/j.cherd.2022.10.007
During the Seminar RE4Industry Knowledge Transfer on 20-22 October 2022 at TU Graz, Inffeldgasse 25/D, i7, Prof. Hacker chaired the session ‘Green Hydrogen’ supported by Prof Lux as expert, and Prof. Kienberger moderated the panel on Circular Bioeconomy.
The ElektroPower project of the Institute of Chemical Engineering and Environmental Technology has been nominated in the category "PROTOTYPE" for the Austrian start-up prize PHÖNIX, which is awarded on behalf of the Federal Ministry of Education, Science and Research (BMBWF) and the Federal Ministry for Digital and Economic Affairs (BMDW).
Michaela Roschger, Sigrid Wolf, Kurt Mayer, Matthias Singer and Viktor Hacker
Alkaline direct ethanol fuel cells (DEFCs) represent an efficient energy conversion device for sustainable ethanol fuel. In this study, a design with new structural parameters for the anodic flow field of the alkaline DEFC was modeled with the aid of computational fluid dynamics and was then actually constructed. Single-cell tests were performed to evaluate the impact of the developed design on fuel cell performance. The results show that fuel cell performance significantly increased when using the improved design in the low-temperature range. The higher the temperature in the cell, the lower the influence of the flow field structure on performance. In addition, the influence of external factors, such as the orientation of the cell, the preheating of the fuel, and the direction of the two fuel flows relative to each other (co-current and counter-current), are shown.
Energies, 2022
doi.org/10.3390/en15197234
For his PhD thesis “Modeling of Interfacial Mass Transfer in Liquid-Liquid Systems”, Roland Nagl received the MegaWATT award for the best annual PhD-thesis in the field of technical thermodynamics at a DACH university. In his thesis Roland Nagl established a modeling framework to investigate the fundamental phenomena which govern the mass transfer through liquid-liquid interfaces in industrial separation processes. The price was awarded by the WATT e.V. during the Thermodynamik-Kolloquium 2022 conference in Chemnitz.
https://www.watt-thermodynamik.de/index.php/die-preistraeger-des-megawatt-preises
TU Graz SciPix is a photo and video competition held at TU Graz, which focuses the spotlight on the diverse research being carried out. With three awarded contributions the institute was very successful this year. The photos and video contributions will first be displayed on the Campus Alte Technik, then moved on to the Campus Neue Technik and finally displayed at the Campus Inffeldgasse.
Winning photos and video:
Link to TU Graz SciPix: https://www.tugraz.at/en/research/research-at-tu-graz/tu-graz-scipix/
Rainbow column: This is the Taylor Couette Disc Contactor, which was used for CO2 purification of a gas stream with sodium hydroxide. The pH curve was visualized in the course of the chemical reaction with a universal indicator. © TU Graz
Taylor lava lamp: The eponymous vortex formations of the Taylor-Couette flow are used to bring immiscible phases into contact (gases, liquids and solids). The solid serves as a heterogeneous catalyst and the red colored solvent extracts the reaction product. © TU Graz
The beauty of the imperfect: During the production of a fuel cell, catalyst ink is ultrasonically sprayed onto the membrane. Perfect homogeneity is essential. Here, the aesthetic pattern was created by too much ink. The swollen membrane is unusable. © TU Graz
Mario Kircher, Georg Rudelstorfer, Michaela Roschger, Michael Lammer, Rafaela Greil and Susanne Lux (from left to right) © TU Graz
To learn about the CO2 problem, the fourth grade students of the Carneri BG/BRG visited the institute on 20 September 2022 and also gained insights into the research work in the field of hydrogen technology.
© TU Graz
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