The Summer School on Advanced Studies of Polymer Electrolyte Fuel Cells was organised for the fourteenth time in cooperation between Yokohama National University and Graz University of Technology.
The seven-day program was opened by Prof. Mitsushima and Prof. Hacker, where they placed an emphasis on the long-standing tradition of the summer school and the cooperation between the Universities. The 14th International Summer School on PEFCs attracted 63 participants from 16 different universities and companies.
The Interreg SI-AT H₂GreenTECH project has successfully reached its finish line! The project partners contributed to the establishment of a hydrogen ecosystem in the field of green hydrogen and hydrogen technologies in the cross-border area Slovenia-Austria. The developed Hydrogen Center, as a B2B web platform and One-stop-shop, is an integrative facilitator and motivator for finding common solutions with its existing and future members that contribute to the improvement of the regional hydrogen ecosystem. It serves companies, researchers, and students by providing information, encouraging research and business networks and collaboration opportunities, sharing knowledge, and improving the flow of innovation in the cross-border area. Two strategic documents to support and guide the further development of the Hydrogen Center were prepared.
Asep Samsudin, Merit Bodner and V. Hacker
Anion exchange membrane fuel cells have unique advantages and are thus gaining increasing attention. Poly(vinyl alcohol) (PVA) is one of the potential polymers for the development of anion exchange membranes. This review provides recent studies on PVA-based membranes as alternative anion exchange membranes for alkaline fuel cells. The development of anion exchange membranes in general, including the types, materials, and preparation of anion exchange membranes in the last years, are discussed. The performances and characteristics of recently reported PVA-based membranes are highlighted, including hydroxide conductivity, water uptake, swelling degree, tensile strength, and fuel permeabilities. Finally, some challenging issues and perspectives for the future study of anion exchange membranes are discussed.
Polymers, MDPI 2022
Silvia Maitz, Matthäus Siebenhofer and Marlene Kienberger
Black liquor, a side stream of the kraft pulping process, contains valuable low molecular weight carboxylic acids and carbohydrates. Hydrothermal treatment and wet oxidation of black liquor with a dry matter content of 43 % were investigated as an approach to convert these carbohydrates to carboxylic acids to increase their concentration. Wet oxidation with H2O2 or O2 at 115–185 °C led to partial degradation of carbohydrates, but no significant formation of the investigated carboxylic acids, glycolic, lactic, formic and acetic acid, was detected. Treatment under N2 atmosphere at 185 and 220 °C finally led to an increase of the hydroxy acid concentration. After two hours of heat treatment at 220 °C, 90 % of the carbohydrates were degraded, coupled with a high carbon conversion efficiency of 32 % based on the formation of lactic acid and glycolic acid, of which the concentrations increased by 51 and 73 %, respectively.
Bioresource Technology Reports, Volume 19, 2022, 101148, ISSN 2589-014X https://doi.org/10.1016/j.biteb.2022.101148.
Roland Nagl, Sandrina Stocker, Patrick Zimmermann and Tim Zeiner
This work examines the mass transfer in reactive liquid-liquid systems applying the dynamic concentration gradient theory (CGT). The CGT is based on a square gradient approach delivering an expression for the Gibbs energy of an inhomogeneous system as basis for the mass transfer in a two-phase system. For this work, the CGT was combined for the first time with a reaction kinetics model to model the reactive mass transfer. The model was validated by experiments. As model reaction the reversible diacetone alcohol formation in a water-toluene system was chosen. To parameterize the Gibbs excess energy model, phase equilibria were measured and furthermore, the predictive power of the model to calculate interfacial tension in equilibrium was also checked by own experiments. To analyze the mass transfer in liquid-liquid systems the model prediction was compared to experimental data from Nitsch-cell experiments. It was found that the model predictions are in excellent agreement to the forward reaction predictions as well as to the backward reaction.
Adrian Drescher and Marlene Kienberger
In today’s linear economy, waste streams, environmental pollution, and social–economic differences are increasing with population growth. The need to develop towards a circular economy is obvious, especially since waste streams are composed of valuable compounds. Waste is a heterogeneous and complex matrix, the selective isolation of, for example, polyphenolic compounds, is challenging due to its energy efficiency and at least partially its selectivity. Extraction is handled as an emerging technology in biorefinery approaches. Conventional solid liquid extraction with organic solvents is hazardous and environmentally unfriendly. New extraction methods and green solvents open a wider scope of applications. This research focuses on the question of whether these methods and solvents are suitable to replace their organic counterparts and on the definition of parameters to optimize the processes. This review deals with the process development of agro-food industrial waste streams for biorefineries. It gives a short overview of the classification of waste streams and focuses on the extraction methods and important process parameters for the isolation of secondary metabolites.
8th Regional Symposium on Electrochemistry of South-East Europe together with the 9th Kurt Schwabe Symposium, 11−15 July 2022, TU Graz
RSE SEE8 was attended by 152 researchers and scientists from 23 countries. The conference days started with plenary lectures by internationally renowned scientists and included nine sessions with 15 keynote lectures on the topics:
Abstract book ISBN: 978-3-85125-907-0
Sigrid Wolf, Michaela Roschger, Boštjan Genorio, Mitja Kolar, Daniel Garstenauer, Brigitte Bitschnau and Viktor Hacker
In this study, Ag-MnxOy/C composite catalysts deposited on reduced graphene oxide (rGO) and, for the first time on N-doped graphene oxide (NGO), were prepared via a facile synthesis method. The influence of the carbon support material on the activity and stability of the oxygen reduction reaction (ORR) and on the tolerance to ethanol in alkaline medium was focused and investigated. The physicochemical properties of the Ag-MnxOy/C catalysts were analyzed by X-ray diffraction (XRD), scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDS), Brunauer–Emmett–Teller (BET) method, atomic absorption spectroscopy (AAS), inductively coupled plasma-mass spectrometry (ICP-MS), and thermogravimetric gas analysis (TGA). Electrochemical characterization was performed by rotating disk electrode (RDE) experiments. The results show that the active manganese species MnO2 was assembled as nanorods and nanospheres on rGO and NGO, respectively. Ag was assumed to be present as very small or amorphous particles. Similar redox processes for Ag-MnxOy/rGO and Ag-MnxOy/NGO were examined via cyclic voltammetry. The Ag-MnxOy/rGO resulted in a more negative diffusion limiting current density of −3.01 mA cm−2 compared to Ag-MnxOy/NGO. The onset potential of approximately 0.9 V vs. RHE and the favored 4-electron transfer pathway were independent of the support material. Ag-MnxOy/NGO exhibited a higher ORR stability, whereas Ag-MnxOy/rGO showed a better ethanol tolerance.
Catalysts 2022, 12 (7), 780.
B. Stoppacher, T. Sterniczky, S. Bock, V. Hacker
Chemical Looping Hydrogen processes among others, show an outstanding potential for the decentralized conversion of biogas into high-purity hydrogen. For the first time, a 10 kWth fixed-bed chemical looping system has been coupled directly to a 3 MWth biogas digester in the southern region of Austria in the scope of the Austrian research project Biogas2H2. This experimental lab system resembles a blueprint for a potential future industrial system design. A comprehensive parameter study pointed out the influence of relevant process parameters (temperature, O/R ratio, reduction time, steam quantity in oxidation) on hydrogen purity and process efficiency. At the optimal operating point (850 °C, O/R 1.2), the process efficiency was comparable to the utilization of synthetic biogas in previous investigations within a deviation of 2.9%. Sulfuric compounds were isolated before entering the chemical looping system in order to avoid harmful contamination of the product hydrogen and performance loss, as investigated in preliminary experiments.
The generated hydrogen was characterized online by ppm-range gas analysis and exhibited a product gas quality of up to 99.998%, with residual CO and CO2 as only contaminants. The fulfillment of the carbon mass balance within a mean deviation of 9% proved the correct quantification. The results indicate that coupling fixed-bed chemical looping systems to biogas plants enables the production of a fuel cell grade hydrogen and a sufficient process efficiency in upgrading local available biogenic and agricultural residuals to high-purity hydrogen.
At this year's DocDays VT, a total of 18 research proposals from different areas of chemical and process engineering were presented. In addition, five presentations as well as seven posters by senior PhD students showed remarkable results. Congratulations to Philipp Rosenauer (Best Poster Award) and Carina Waldner (Best Presentation Award). As keynote speaker, Christian Witz (SimVantage) gave insights into the simulation of bioreactors and the difficulties of founding a start-up. The mini-conference ended in a relaxed and summery way with a barbecue, supported by members of STV VT.
Book of Abstracts
The next DocDays 2023 will take place on July 3, 2023 (scheduled); we are already looking forward to this interesting event!
Wolfgang Bauer, Viktor Hacker, Carina Waldner (Best Presentation Award) and Johannes Khinast © TU Graz
S. Bock, M. Pauritsch, S. Lux, V. Hacker
The potential of the extremely low-cost alternative of energy and hydrogen storage in the form of natural iron ores has been extensively studied and evaluated both theoretically and experimentally. Natural iron ores as storage materials are advantageous because the specific costs are an order of magnitude lower compared to synthetic iron oxide-based materials. For this purpose, regionally available siderite, a carbonate-bearing iron ore, with low reaction temperatures and high storage capacity was investigated in comparison with commercial iron ores such as ilmenite and others. Specific storage costs are 80-150 $/MWh of hydrogen stored, based on experimental in situ tests. The experimentally determined volumetric energy storage capacity for the bulk material was 1.7 and 1.8 MWh/m3 for hydrogen and heat release, respectively. The raw siderite ore was stable in in situ life tests for 50 consecutive cycles at operating temperatures of 500-600 °C. The low material price combined with reasonable storage capacity results in very low specific storage costs of 0.075 $/kWh and 0.08-0.15 $/kWh for heat and hydrogen storage, respectively.
Energy Conversion and Management, Elsevier 2022
Maximilian Neubauer, Thomas Wallek, Susanne Lux
One of the most common techniques for separating azeotropes and close-boiling mixtures is extractive distillation, where the relative volatility of the components to be separated is altered by adding an entrainer. In recent years, deep eutectic solvents have emerged as a new class of entrainers in extractive distillation. Similar to the related class of ionic liquids, deep eutectic solvents combine the high separation capability of solid salts with the simple handling of liquids, additionally exhibiting low to negligible vapour pressures and non-flammability. Compared to ionic liquids, deep eutectic solvents offer advantages in terms of toxicity issues but also solvent costs. In this review, the current state of research regarding deep eutectic solvents in extractive distillation spanning from vapour-liquid- equilibrium measurements and thermodynamic modelling of the corresponding systems to general entrainer feasibility considerations and process simulations is presented and critically evaluated. Additionally, future prospects and comments on unresolved issues are provided.
Chemical Engineering Research and Design 184 (2022) 402-418
For the project ‘On-site Biogas Utilization for Decentralized Hydrogen Production (Biogas2H2)’, the project team was awarded the Sustainability Award 2022, field of action Regional Cooperation, 3rd place by the Federal Ministry of Education, Science and Research (BMBWF - BM Polaschek) and the Federal Minister for Climate Action, Environment, Energy, Mobility, Innovation and Technology (BMK - BM Gewessler). on June 13, 2022 at the Technical Museum Vienna.
TU Graz PURE
Thomas Pichler received for his PhD thesis with the title “ Processing of Lignin: Development of Precipitation and Modification Processes” the Mondi/Heinzel/SAPPI award in the category Pulping Process (including utilization of side streams from the pulping process). Thomas Pichler developed basics for the absorption of CO2 in NaOH, which was the basis for the development of an air lift reactor for lignin precipitation and isolation. He received the price during the Pulp& Biorefinery conference on 24th of May 2022 in Graz.
During the Long Night of Research at the campus “Neue Technik” (Graz University of Technology), the working group for Chemical Reaction Engineering, headed by Susanne Lux, represented a research focus in cooperation with the student representative Chemical Engineering.
To show and explain the different operation modes in reactors for gas-liquid reaction to many visitors, the demonstration model of the Taylor Couette Disc Contactor (TCDC) and the Taylor Couette Reactor was used. During operation, the stabilized flow regime in the Taylor Couette Disc Contactor, which was developed at the CEET, was shown to the visitors. Furthermore, different possible operation modes in the TCDC, for example the chemisorption of carbon dioxide for the purification of industrial flue gas, were explained. Due to the clarity of the process and additional information from the student representatives, young visitors were given an understanding of the research focus of the working group and also the study of chemical engineering in order to attract new students to the study of chemical engineering.
Demonstration model of the Taylor Couette Disc Contactor and the Taylor Couette Reactor with (from left to right) Alexandra Hutter (student representative Chemical Engineering), Rafaela Greil (CEET) and Peter Holzmann (student representative Chemical Engineering) at the Long Night of Research 2022 at Graz University of Technology
During the Long Night of Research at Graz University of Technology, the research group of fuel cells at the Institute of Chemical Engineering and Environmental Technology, headed by Prof. Viktor Hacker, gave insights into the topics of hydrogen and fuel cells as part of the ongoing international networking project H2GreenTECH.
Using the demonstration model built as part of the H2GreenTECH project, the environmentally friendly production, storage and use of hydrogen as a fuel instead of fossil fuels was vividly explained to many visitors. The generation of renewable energy by photovoltaic cells and its further use for the production of green hydrogen by an electrolyser was demonstrated. Hydrogen storage and easy energy recovery (whenever needed) through a fuel cell were also demonstrated. By showing the demonstration model, young visitors were also able to get excited about hydrogen technology. Through the distribution of promotional materials (bags, mugs, notebooks), the awareness gained about renewable energy and the environment will be remembered by the visitors for a long time through daily use.
Information table on the energy cycle of hydrogen with the CEET team (from left to right: Mario Kircher, Prof. Viktor Hacker, Michaela Roschger, Sigrid Wolf, Karin Malli) at the Long Night of Research 2022 at TU Graz. Presentation of the demo test rig (right).
This work demonstrates how to apply the Theory of Inventive Problem Solving (Russian acronym TRIZ) on two industrial-scale case studies. The first case study addresses processing of mineral metal carbonates, which is characterized by high CO2 emissions and high energy demand. As solver strategy a novel reductive pathway is suggested. The second case study refers to biobased industrial processes, which discharge aqueous effluents with unexploited carboxylic acid loads. Reactive separations are proposed to isolate the carboxylic acids. In both solver strategies, chemical reactions adopt a central role.
Chemie Ingenieur Technik (2022)
Fabian Zapf, Thomas Wallek
This work demonstrates a case-study to create machine-learning based process models from process data, which are connected into an overall process flowsheet and provide a high level of numerical stability for further multi-objective optimization. The used models are black-box and gray-box models, which are further compared to the proven LP approach. The proposed methodology is demonstrated using real- world measurement data from a refinery, involving a distillation unit, a hydrotreater, a reformer and an ethylene plant. The developed unit models are connected into an overall process flowsheet, which is solved by a sequential-modular approach and optimized in view of maximizing production margin and minimizing CO2 -emissions. This work points out that the combination of engineering knowledge with data-driven techniques enables the incorporation of indirect information for process units, e.g., the crude oil composition vector for downstream units, leveraging the prediction performance of the unit models, compared to models not involving this information.
Computers and Chemical Engineering 162 (2022) 107823
Sascha Kleiber, Astrid Loder, Matthäus Siebenhofer, Andreas Böhm, Susanne Lux
Industrial CO2 emission mitigation necessitates holistic technology concepts; especially in high-emission industrial sectors like the iron and steel industry. A novel direct reduction technology with hydrogen reduces CO2 emissions in iron production from siderite ore by more than 60 %. Subsequent valorization of the process gas, consisting of unconverted hydrogen, carbon monoxide, and CO2, by catalytic hydrogenation to methane and methanol completes the technology concept. This route gives access to CO2 emission-lean iron production from siderite ore, fossil-free methane and methanol synthesis, and thus, improved energy density of the energy carrier hydrogen.
Chem. Ing. Tech.2022,94, No. 5, 701–711
Georg Rudelstorfer, Maximilian Neubauer, Matthäus Siebenhofer, Susanne Lux and Annika Grafschafter
Isolation of carboxylic acids from dilute aqueous effluents can be achieved by the combination of liquid-phase catalyzed reaction with liquid-liquid extraction. Exemplarily the heterogeneously catalyzed esterification of acetic acid with methanol, accelerated with a cation-exchange resin and simultaneous transfer of the product methyl acetate into the solvent ShellSol T, was successfully performed in a Taylor-Couette disc contactor (TCDC) in batch operation mode. Stable three-phase flow (liquid-liquid-solid) was confirmed in lab scale. The conversion of acetic acid in a TCDC operated in batch mode compares well with conversion in a batch reactor.
ChemieIngenieurTechnik, Volume94, Issue5, Special Issue: Chemische Reaktionstechnik, May 2022, 671-680
One of the flagship projects of the "Digital TU Graz" is the participatory innovation program "Digital TU Graz Marketplace", which transfers methodical and technical innovations in the form of funded pilot projects to university practice in the long term.
Sascha Kleiber, Michael Haring and Thomas Wallek are one of the winning teams in the Digital TU Graz Marketplace 2022 competition. Beginning April 1, 2022, the three will implement a digital innovation project in teaching aimed at new methods of imparting knowledge in courses:
For further information, including a pitch video, click here <https://my.ltb.io/www/#/ > or follow the QR-Code:
RSE-SEE8. The 8th Regional Symposium on Electrochemistry for Southeast Europe will be organized by us at TU Graz from 11-15 July 2022.
ESAT 2022. We are proud to announce that the 32nd European Symposium on Applied Thermodynamics will be held in Graz from 17-20 July 2022.
Summer School on Fuel Cells & Hydrogen. We are co-organizers of the next summer school at Yokohama National University, Japan from 29 Aug – 3 Sept 2022. Join us!