Publikationen
Other Publications | 2024
Predictive Building Energy Management with User Feedback in the Loop
Kaisermayer V, Muschick D, Gölles M, Horn M. Predictive Building Energy Management with User Feedback in the Loop. Centre's Day 2024.
Download PDF DetailsPeer reviewed papers | 2024
Predictive building energy management with user feedback in the loop
Kaisermayer V, Muschick D, Horn M, Schweiger G, Schwengler T, Mörth M, Heimrath R, Mach T, Herzlieb M, Gölles M. Predictive building energy management with user feedback in the loop. Smart Energy. November 2024(16):100164.
External Link Details AbstractRetrofitting buildings with predictive control strategies can reduce their energy demand and improve thermal comfort by considering their thermal inertia and future weather conditions. A key challenge is minimizing additional infrastructure, such as sensors and actuators, while ensuring user comfort at all times. This study focuses on retrofitting with intelligent software, incorporating the users’ feedback directly into the control loop. We propose a predictive control strategy using an optimization-based energy management system (EMS) to control thermal zones in an office building. It uses a physically motivated grey-box model to predict and adjust thermal demand, with individual zones modelled using an RC-approach and parameter estimation handled by an unscented Kalman filter (UKF). This reduces deployment effort as the parameters are learned from historical data. The objective function ensures user comfort, penalizes undesirable behaviour and minimizes heating and cooling costs. An internal comfort model, automatically calibrated with user feedback by another UKF, further improves system performance. The practical case study is an office building at the ”Innovation District Inffeld”. Operation of the system for one year yielded significant results compared to conventional control. Thermal comfort was improved by 12% and thermal energy consumption for heating and cooling was reduced by about 35%.
Conference presentations and posters | 2023
Predictive control of biomass and biogas-based CHPs at the intersection between the electricity grid and heating networks – Improving electricity market participation through optimization and demand side management
Muschick D, Kaisermayer V, Moser A, Gölles M. Predictive control of biomass and biogas-based CHPs at the intersection between the electricity grid and heating networks – Improving electricity market participation through optimization and demand side management. 7. Mitteleuropäische Biomassekonferenz: CEBC 2023. 20. Jan 2023. Oral presentation.
Download PDF DetailsConference Papers | 2024
Predictive Rule-Based Control Strategy for Optimizing the Operation of Solar District Heating Plants
Unterberger V, Lichtenegger K, Gölles M. Predictive Rule-Based Control Strategy for Optimizing the Operation of Solar District Heating Plants. In: Proceedings of EuroSun 2024: 15th International Conference on Solar Energy for Buildings and Industry. 26.-30. August 2024. Limassol. 382-390.
External Link DetailsConference presentations and posters | 2021
Price cointegration in the Austrian sawmill industry with a focus on by-products
Fuhrmann M, Dißauer C, Strasser C, Schmid E. Price cointegration in the Austrian sawmill industry with a focus on by-products. 29th European Biomass Conference and Exhibition, EUBCE 2021. 26-29 April 2021.
DetailsConference presentations and posters | 2014
Price cointegration in the Austrian wood fuel market,
Kristöfel C, Morawetz UB, Schmid E, Strasser C. Price cointegration in the Austrian wood fuel market, 22nd European Biomass Conference 2014, 23rd-26th of June 2014, Hamburg, Germany. p 1330-1335.
Details AbstractThe wood fuel market is connected to the forestbased industry in various ways: the sawmill by products such as sawdust and wood chips are usually used as raw material in the panel, pulp and paper industry and are increasingly pelletized to supply the energy commodity market. Hence, the question arises whether or not prices of these woody biomass commodities are integrated. Threshold cointegration and asymmetric error correction models are used to analyze the price dynamics between roundwood, wood pellets and sawmill by products. Results indicate that a statistical significant price transmission between sawmill byproducts and wood pellets, but wood pellet and roundwood prices are not integrated. The price transmission between wood pellets and sawdust as well as wood chips is asymmetric. The Granger Causality test reveals that the prices of sawdust and wood chips depend on the price of wood pellets.
Conference presentations and posters | 2009
Primary measures for low-emission residential wood combustion – comparison of old with optimised modern systems
Brunner T, Obernberger I, Scharler R. Primary measures for low-emission residential wood combustion – comparison of old with optimised modern systems, 17th European Biomass Conference 2009, 29th of June-3rd of July 2009, Hamburg, Germany.
DetailsConference presentations and posters | 2020
Primary- and Secondary Measures for Manually Fired Stoves - An Overview
Reichert G. Primary- and Secondary Measures for Manually Fired Stoves - An Overview. 6th Central European Biomass Conference, 2020, Graz.
Download PDF DetailsConference presentations and posters | 2020
Primary- and Secondary Measures for Manually Fired Stoves – An Overview
Reichert G. Primary- and Secondary Measures for Manually Fired Stoves – An Overview. 6th Central European Biomass Conference - KeepWarm/CleanAir workshop (oral presentation). 2020.
External Link Download PDF DetailsOther Publications | 2019
Primäre und sekundäre Verbesserungen an einem Biomassekessel für Agrarbrennstoffe
Zemann C, Kelz J, Muschick D, Retschitzegger S, Gölles M. Primäre und sekundäre Verbesserungen an einem Biomassekessel für Agrarbrennstoffe. 10. Fachgespräch: Partikelabscheider in häuslichen Feuerungen. 20. März 2019 (2019). [online]. (Tagungsreader, 15). Leipzig: DBFZ. 168 S.
External Link Download PDF Details Abstractie Biomasseverbrennung spielt eine zentrale Rolle bei der Bereitstellung von Wärme aus erneuerbaren Energieträgern. Konventionelle Biomasse-Brennstoffe werden jedoch aufgrund einer steigenden Anzahl stofflicher Verwertungsmöglichkeiten, wie z.B. der Umwandlung in Chemikalien, teurer und schwieriger zugänglich. Agrarbrennstoffe, die bisher nur selten oder gar nicht in Biomasse-Kleinfeuerungen eingesetzt wurden, stellen eine vielversprechende Alternative zu konventionellen Brennstoffen dar. Diese Agrarbrennstoffe, wie zum Beispiel Kurzumtrieb, Maisspindeln oder Stroh sind kostengünstig und in ausreichender Menge vorhanden. Der Einsatz von Agrarbrennstoffen in konventionellen Biomasse-Kleinfeuerungen ist jedoch aufgrund stark variierender Brennstoffeigenschaften mit erhöhten Anforderungen an das Verbrennungssystem verbunden. Erhöhte N, S, Cl, Alkalimetall- und Aschegehalte sowie niedrigere Aschenschmelzpunkte können zu aschebedingten Problemen (Ascheschmelze, Ascheablagerung und Korrosion) sowie erhöhten Konzentrationen von gasförmigen (CO, NOx, HCl und SOx) und partikelförmigen Emissionen bei der Verbrennung führen.
Ziel der in diesem Beitrag präsentierten Arbeiten war die Erhöhung die Brennstoffflexibilität einer handelsüblichen Biomasse-Kleinfeuerung um damit eine Verbrennung von Agrarbrennstoffen mit niedrigen Schadstoffemissionen und einem hohen Wirkungsgrad zu ermöglichen. Hierzu wurde eine modellbasierte Regelung entwickelt, welche insbesondere eine gezielte Einstellung des Luftverhältnisses in der Primärverbrennungszone ermöglicht und damit das Risiko der Ascheschmelze reduziert und Schadstoffmissionen verringert. Soft-Sensoren bestimmen relevante Brennstoffeigenschaften während des Betriebs, welche von der modellbasierten Regelung zur automatischen Anpassung an geänderte Brennstoffeigenschaften genutzt werden. Die modellbasierte Regelung wurde um eine CO-lambda-Optimierung ergänzt, welche auf Basis von Messwerten des Restsauerstoffgehalts und der CO-Emissionen den Wirkungsgrad der Verbrennung maximiert und gleichzeitig die Schadstoffemissionen verringert. Zur weiteren Verringerung von partikelförmigen Schadstoffemissionen wurde ein am Markt verfügbarer Elektrofilter adaptiert und nach dem Wärmeübertrager der Biomasse-Kleinfeuerung angebracht.
Dieses Verbrennungssystem wurde durch umfassende Testläufe mit begleitenden Emissionsmessungen sowie Brennstoff-, Staub- und Ascheanalysen bewertet. Der Einsatz der modellbasierten Regelung führte zu einem stabileren Betrieb bei allen Leistungen und für alle Brennstoffe. Der Elektrofilter zeigte sehr zufriedenstellende Abscheidegrade für alle untersuchten Brennstoffe und Anlagenleistungen. Dadurch konnte die Brennstoffflexibilität der handelsüblichen Biomasse-Kleinfeuerung erhöht und die Verbrennung von Agrarbrennstoffen ermöglicht werden.
Other Publications | 2021
Probenahmen, Messung, Behandlung von Chrom VI in Holzaschen
Retschitzegger S. Probenahmen, Messung, Behandlung von Chrom VI in Holzaschen. 23. Österreichischer Biomassetag & Heizwerke-Betreibertag. September 2021.
DetailsConference presentations and posters | 2012
Processing Options Of Heavy Fractions From MBT Plant
Meirhofer M, Ragoßnig AM, Sommer M. Processing Options Of Heavy Fractions From MBT Plant, ISWA Annual Congress Florence 2012, 18th of September 2012, Florence, Italy.
DetailsConference presentations and posters | 2012
Processing Options Of Heavy Fractions From MBT Plants
Meirhofer M, Ragoßnig AM, Sommer M. Processing Options Of Heavy Fractions From MBT Plants, ISWA Annual Congress Florence 2012, 17th-19th of September 2012, Florence, Italy. (peer reviewed)
Details AbstractHeavy fractions resulting from mechanical treatment stages of Mechanical Biological Treatment (MBT) plants are posing very specific demands with regard to further treatment/disposal as they contain a high portion of inert material as well as a high portion of high calorific components. Based on the current Austrian legal situation (landfill ordinance: max. Higher Calorific Value (HCV) for MBT-fractions to be landfilled = 6,600 kJ/kg DM) this waste stream cannot be landfilled but must be thermally treated. In economic terms it is desirable to separate high calorific from inert waste components in order to allow for a material specific routing taking advantage of the difference in the costs for the downstream treatment / disposal.
In this conference contribution results of extensive processing experiments with the heavy fraction from the mechanical stage of the MBT plant of Umweltdienst Burgenland in Oberpullendorf, Austria, are presented. Experiments have been conducted with three different sensor-based automatic sorting systems (NIR – Multiplexer, NIR – Spectral Imaging, X-Ray transmission) as well as two density based processing technologies (wet treatment with a jigger, dry treatment with a cross flow air separation device). In addition a rotary shredder, which allows selective crushing, followed by screening has been investigated.
The performance of the processing options have been evaluated by characterizing the resulting product streams by means of manual sorting in order to evaluate purity and yield achieved by the respective treatment options. In addition to that chemical and physical parameters relevant for further treatment / disposal steps for the resulting product streams have been analysed. The inert fraction has been evaluated regarding the landfilling on a mass waste landfill on one hand and on a C&D waste landfill on the other hand. The high calorific product stream has been evaluated with regard to its thermal utilization.
Complementing the technical evaluation of the processing options an economical assessment of the processing options looked at including the economical implications of the resulting changes in the routing of the waste streams has been conducted.
Conference presentations and posters | 2020
Product flexibility from biomass steam gasification applying gas upgrading and synthesis processes
Binder M, Product flexibility from biomass steam gasification applying gas upgrading and synthesis processes. 6th Central European Biomass Conference, 22-24 January 2020, Graz.
Download PDF DetailsReports | 2016
Production of advanced biofuels
Bacovsky D. Production of advanced biofuels. Nationaler Workshop Biotreibstoffe. September 2016.
External Link Download PDF DetailsConference presentations and posters | 2017
Production of Fuel Ethanol and Higher Alcohols from Biomass Residue
Summers M, Liao C, Hoffman M, Hart M, Seiser R, Neimann U, Cattolica R, Rauch R, Binder M. Production of Fuel Ethanol and Higher Alcohols from Biomass Residue. 25th European Biomass Conference & Exhibition (oral presentation). June 2017, Stockholm, Sweden.
External Link DetailsConference presentations and posters | 2015
Production of high purity hydrogen from biomass-derived synthesis gas using dual fluidised bed gasification technology
Loipersböck J., Rehling B., Rauch R., Hofbauer H. Production of high purity hydrogen from biomass-derived synthesis gas using dual fluidised bed gasification technology, 23rd European Biomass Conference 2015, 1st-4th of June 2015, Vienna, Austria. (oral presentation)
DetailsConference presentations and posters | 2013
Production of mixed alcohols from biomass-derived synthesis gas using a sulfidized molybdenum catalyst
Weber G, Rauch R, Hofbauer H. Production of mixed alcohols from biomass-derived synthesis gas using a sulfidized molybdenum catalyst, International Conference on Polygeneration Strategies 2013, 3th-5th of September 2013, Vienna, Austria. Weber G, Rauch R, Hofbauer H. Production of mixed alcohols from biomass-derived synthesis gas using a sulfidized molybdenum catalyst, International Conference on Polygeneration Strategies 2013, 3th-5th of September 2013, Vienna, Austria. (peer reviewed)
DetailsConference presentations and posters | 2010
Production of Synthetic Biofuels in existing Industry - Simulation of FICFB and Fischer - Tropsch - Process in IPSEpro
Weber G, Potetz A, Rauch R, Hofbauer H. Production of Synthetic Biofuels in existing Industry - Simulation of FICFB and Fischer - Tropsch - Process in IPSEpro, ICPS 2010, 7th-9th of September 2010, Leipzig, Germany.
Details AbstractIn cooperation between Vienna University of Technology and Bioenergy 2020+ a project was done which had the objective to evaluate the prospects for the production of Biofuels by integration in existing Austrian biomass industry. The advantages of such integration are the good access to renewable energy resources like wood chips, existing infrastructure for electricity and heat, existing logistics of resources and the utilization of waste heat from Biofuel production to substitute fossil fuels. One work package included the process simulation of thermo-chemical biomass gasification and the production of a second generation Biofuel by the use of Fischer – Tropsch (FT) - synthesis. The process simulation tool IPSEpro was used for the simulation. The simulation of technical processes allows the prediction of the behavior of processes on the base of mathematical models. The quality of a simulation model depends substantially on the used model and the process parameters. The used technologies in the process simulation were the biomass gasification with the Fast Internal Circulating Fluidized Bed (FICFB) – gasification system and the Fischer –Tropsch (FT) - synthesis. The FICFB was developed by the Vienna University of technology. This gasification technology is used in the well known demonstration plant is Güssing (Austria). The produced product gas is nearly nitrogen free and has a high content of hydrogen (45 – 35 Vol%dry) and carbon monoxide (25 – 20 Vol%dry). These product gas components are used in the FT - synthesis for the production of FT – raw product. A FT - Trial Plant is also situated in Güssing since the year 2005. A slurry reactor is used in the Trial Plant for the FT – synthesis. The target for the simulation was the production of FT – raw product as well as the substitution of fossil fuels. The waste heat of the process should be used for the production of steam. An amount of 120 tons per hour of fossil produced steam should be substituted. The
Off-Gas of the FT – process was also used for the production of steam. Two different models for location number one were considered. The used fuel was wood chips. The data out of the simulation were used to calculate the economic efficiency of the plants. An important parameter was the price of the FT – raw product per liter. The total costs and the production capacity were set equal to calculate the marginal revenue. Also a sensitivity analysis was done to evaluate the effects of rising fuel costs and increased investment costs.
Conference presentations and posters | 2012
Produktentwicklung von Biomassekesseln – Rollenprüfstandstest für Biomassekessel kleiner Leistung
Haslinger W. Produktentwicklung von Biomassekesseln – Rollenprüfstandstest für Biomassekessel kleiner Leistung, Innovationsforum Ökoenergie-Cluster 2012, 18th of October 2012, Linz, Austria.
DetailsOther papers | 2016
Progress in hydrogen production from product gas generated by dual fluidized bed biomass steam gasification
Kraussler M, Hofbauer H. Progress in hydrogen production from product gas generated by dual fluidized bed biomass steam gasification. 24th European Biomass Conference & Exhibition (oral presentation). June 2016, Amsterdam, Netherlands.
DetailsOther Publications | 2016
Progress in Mixed Alcohol Synthesis - Based on Wood Gas Derived from Dual Fluidized Bed Biomass Steam Gasification
Binder, M., Weber, G., Rauch, R., Hofbauer, H.: Progress in Mixed Alcohol Synthesis - Based on Wood Gas Derived from Dual Fluidized Bed Biomass Steam Gasification. Poster presentation at CASCATBEL workshop 2016, 18 - 20 May 2016, Porto Carras, Greece.
DetailsPeer reviewed papers | 2020
Progressive Hedging for Stochastic Energy Management Systems: The Mixed-Integer Linear Case
Kaisermayer V, Muschick D, Gölles M, Horn M. Progressive Hedging for Stochastic Energy Management Systems: The Mixed-Integer Linear Case. Energy Systems. 2020 Aug 29. https://doi.org/10.1007/s12667-020-00401-z
External Link Details AbstractEnergy systems have increased in complexity in the past years due to the everincreasing integration of intermittent renewable energy sources such as solar thermal or wind power. Modern energy systems comprise different energy domains such as electrical power, heating and cooling which renders their control even more challenging. Employing supervisory controllers, so-called energy management systems (EMSs), can help to handle this complexity and to ensure the energy-efficient and cost-efficient operation of the energy system. One promising approach are optimization-based EMS, which can for example be modelled as stochastic mixed-integer linear programmes (SMILP). Depending on the problem size and control horizon, obtaining solutions for these in real-time is a difficult task. The progressive hedging (PH) algorithm is a practical way for splitting a large problem into smaller subproblems and solving them iteratively, thus possibly reducing the solving time considerably. The idea of the PH algorithm is to aggregate the solutions of subproblems, where artificial costs have been added. These added costs enforce that the aggregated solutions become non-anticipative and
are updated in every iteration of the algorithm. The algorithm is relatively simple to implement in practice, re-using almost all of a possibly existing deterministic implementations and can be easily parallelized.
Although it has no convergence guarantees in the mixed-integer linear case, it can nevertheless be used as a good heuristic for SMILPs. Recent theoretical results shown that for applying augmented Lagrangian functions in the context of mixed-integer programmes, any norm proofs to be a valid penalty function. This is not true for squared norms, like the squared L 2 -norm that is used in the classical progressive hedging algorithm. Building on these theoretical results, the use of the L 1 and L-infinity-norm in the PH algorithm is investigated in this paper. In order to incorporate these into the algorithm an adapted multiplier update step is proposed. Additionally a heuristic extension of the aggregation step and an adaptive penalty parameter update scheme from the literature is investigated. The advantages of the proposed modifications are demonstrated by means of illustrative examples, with the application to SMILP-based EMS in mind.
Conference presentations and posters | 2014
Promotion of bioenergy initiatives in Centru Region, Romania
Kristöfel C, Ehrig R, Strasser C. Promotion of bioenergy initiatives in Centru Region Romania, 4th Central European Biomass Conference 2014, 15th-18th of January 2014, Graz, Austria.
DetailsConference presentations and posters | 2014
Promotion of successful bioenergy initiatives in Eastern Europe
Kristöfel C. Promotion of successful bioenergy initiatives in Eastern Europe, Word Sustainable Energy Days 2014, 26th-28th of February 2014, Wels, Austria. (visual presentation)
DetailsOther papers | 2013
Pseudo heterogeneous modeling of catalytic methane steam reforming process in a fixed bed reactor
Sadooghi P, Rauch R. Pseudo heterogeneous modeling of catalytic methane steam reforming process in a fixed bed reactor. Journal of Natural Gas Science and Engineering. 2013;11:46-51.
External Link Details AbstractA mathematical model is developed to simulate synthesis gas production by methane steam reforming process in a fixed bed reactor filled with catalyst particles. Due to the endothermic nature of the reforming reactions heat is supplied into the reactor by means of electrical heating, therefore, the reactor and catalyst particles are exposed to significant axial and radial temperature gradients. A pseudo heterogeneous model is used in order to exactly represent diffusion phenomena inside the reactor tube. Heat and mass transfer equations are coupled with detailed reaction mechanisms and solved for both the flow phase and within the catalyst pellets. The reaction has been investigated from a modeling view point considering the effect of different temperatures ranging from 873 to 1073 (K) on methane conversion and hydrogen yields. The result provides temperature and concentration distribution along the reactor axial and radial coordinates and strong radial temperature gradients particularly close to the entrance of the reactor have been found. © 2013 Elsevier B.V.
Other papers | 2013
Pulmonary inflammation and tissue damage in the mouse lung after exposure to PM samples from biomass heating appliances of old and modern technologies
Happo MS, Uski O, Jalava PI, Kelz J, Brunner T, Hakulinen P, et al. Pulmonary inflammation and tissue damage in the mouse lung after exposure to PM samples from biomass heating appliances of old and modern technologies. Sci Total Environ. 2013;443:256-66.
External Link Details AbstractCurrent levels of ambient air fine particulate matter (PM2.5) are associated with mortality and morbidity in urban populations worldwide. In residential areas wood combustion is one of the main sources of PM2.5 emissions, especially during wintertime. However, the adverse health effects of particulate emissions from the modern heating appliances and fuels are poorly known. In this study, health related toxicological properties of PM1 emissions from five modern and two old technology appliances were examined. The PM1 samples were collected by using a Dekati® Gravimetric Impactor (DGI). The collected samples were weighed and extracted with methanol for chemical and toxicological analyses. Healthy C57BL/6J mice were intratracheally exposed to a single dose of 1, 3, 10 or 15mg/kg of the particulate samples for 4, 18 or 24h. Thereafter, the lungs were lavaged and bronchoalveolar lavage fluid (BALF) was assayed for indicators of inflammation, cytotoxicity and genotoxicity. Lungs of 24h exposed mice were collected for inspection of pulmonary tissue damage. There were substantial differences in the combustion qualities of old and modern technology appliances. Modern technology appliances had the lowest PM1 (mg/MJ) emissions, but they induced the highest inflammatory, cytotoxic and genotoxic activities. In contrast, old technology appliances had clearly the highest PM1 (mg/MJ) emissions, but their effect in the mouse lungs were the lowest. Increased inflammatory activity was associated with ash related components of the emissions, whereas high PAH concentrations were correlating with the smallest detected responses, possibly due to their immunosuppressive effect. © 2012 Elsevier B.V.
Other Publications | 2013
Pylogenetic (SSU) and Fatty Acid Analysis of Several Algal Strains within the Trebouxiophyceae and Implications for Commercial Purposes
Gruber M, Darienko T, Pröschold T, Jirsa F, Schagerl M. Pylogenetic (SSU) and Fatty Acid Analysis of Several Algal Strains within the Trebouxiophyceae and Implications for Commercial Purposes, 21st European Biomass Conference and Exhibition 2013, 3rd-7th of June 2013, Copenhagen, Denmark.
DetailsOther Publications | 2024
Pyrolysetechnologien in Europa
Technologieübersicht mittelschneller Pyrolyse für dezentrale Anwendungen, für kleine und mittlere Unternehmen und für die Kreislaufwirtschaft
Klauser F, Schwarz M, Schwabl M, Wopienka E, Fuhrmann M, Dissauer C. Pyrolysetechnologien in Europa, BMK.14/2024
External Link Details AbstractPyrolyse ist ein althergebrachtes Verfahren, das bereits vor Jahrtausenden zur Herstellung von Kohle praktiziert wurde. Bestrebungen nach Unabhängigkeit von fossilen Ressourcen und klimaneutralen sowie kreislaufwirtschaftlichen Wertschöpfungsketten, führen aktuell zu deutlich steigendem Interesse an dieser Technologie. Durch vielseitige verfahrenstechnische Ausgestaltungsmöglichkeiten stellt die Pyrolyse eine potenzielle Schlüsseltechnologie für verschiedene zum Teil hoch spezifische Anwendungen für stoffliche und energetische Prozessketten dar. Diese Vielfalt an Möglichkeiten resultiert jedoch gleichzeitig in einer hohen Komplexität, die es erschwert einen Überblick über angebotene Anlagen zu bekommen.
Ziel dieser Studie ist es, Informationen vielfältiger Systeme in eine vergleichbare Form zu bringen und dadurch eine Übersicht für Interessierte zu ermöglichen. Der Aufwand der Informationsbeschaffung als initialer Schritt für Umsetzungen soll dadurch reduziert werden. Hierdurch soll zur Realisierung regionaler Pyrolyseprojekte als Bestandteil kreislaufwirtschaftlicher Stoffnutzungskonzepte beigetragen werden.
Peer reviewed papers | 2024
Pyrolysis of industrial hemp biomass from contaminated soil phytoremediation: kinetics, modelling transport phenomena and biochar-based metal reduction
Voglar J, Prašnikar A, Moser K, Carlon E, Schwabl M, Likozar B. Pyrolysis of industrial hemp biomass from contaminated soil phytoremediation: kinetics, modelling transport phenomena and biochar-based metal reduction. Thermochimica Acta.2024.742:179899
External Link Details AbstractPhytoremediation is the use of vegetation for the in situ treatment of contaminated environments. After plants have been used for phytoremediation of soils, their biomass can be used for example as value-added products or converted by thermochemical processes. Large-scale application of pyrolysis technology for phytoremediation biomass requires accurate predictive kinetic models and a characterization of the toxicity of the materials produced. The pyrolysis of industrial hemp (Cannabis sativa L.) was investigated on a laboratory scale by varying the process conditions and accurately modelled by considering four pseudo-components with first reaction order. The average value of the coefficients of determination is 0.9980. Biomass and biochar were characterized and the main components of the gas phase were monitored. We found Cd, Pb, and Zn in the roots, although in lower amounts than in the soil. Especially the leaves and stems showed negligible traces of these elements, so that these parts can be used directly, even if the hemp was grown on the polluted soil. After pyrolysis, the concentration of pollutants in the solid fraction decreased, which could be attributed to the reduction of metal oxides (or salts) to elemental form and subsequent evaporation. This pyrolysis process has the potential to treat heavy metal-rich biomass, with gas phase purification via condensation, yielding agricultural-grade biochar, CO-rich gas and a highly concentrated heavy metal stream in absorbent material.
Peer reviewed papers | 2017
Pyrolysis of pellets made with biomass and glycerol: Kinetic analysis and evolved gas analysis
Bartocci P, Anca-Couce A, Slopiecka K, Nefkens S, Evic N, Retschitzegger S, Barbanera M, Buratti C, Cotana F, Bidini G, Fantozzi F. Pyrolysis of pellets made with biomass and glycerol: Kinetic analysis and evolved gas analysis. Biomass and Bioenergy. February 2017;97: 11-19.
External Link Details AbstractGlycerol is a co-product compound of biodiesel production with an interesting heating value. In this work pyrolysis kinetic parameters for a pellet made with a mass fraction of 90% sawdust and a mass fraction of 10% glycerol are derived through thermogravimetric analysis. A new parallel reaction scheme with four components (cellulose, hemicellulose, lignin and glycerol) is adopted and the kinetic triplet for each component is derived using a model fitting approach applied to this particular kind of pellet. The isoconversional method Kissinger-Akahira-Sunose is employed both to provide initial values for model fitting simulations and to check final results. Results show that activation energies and pre-exponential factors are respectively: 149.7 kJ mol−1 and 1.98*1011 s−1 for hemicellulose, 230.1 kJ mol−1 and 1.84*1017 s−1 for cellulose, 154.3 kJ mol−1 and 5.14*109 s−1 for lignin, 74.5 kJ mol−1 and 2.17*105 s−1 for glycerol with a first reaction order for all components, except for lignin (n = 2.6). Through evolved gas analysis it was demonstrated that the thermal degradation of glycerol contained in the pellet can increase hydrogen content in pyrolysis gases.
Other papers | 2017
Pyrolysis of sewage sludge to produce fuels and chemical feedstock
Wartha C, Kranner R, Meirhofer M. Pyrolysis of sewage sludge to produce fuels and chemical feedstock. 5th Central European Biomass Conference (Poster). January 2017, Graz, Austria.
DetailsConference presentations and posters | 2009
Quality Check for European Wood Pellets
Wopienka E, Griesmayr S, Friedl G, Haslinger W. Quality Check for European Wood Pellets, 17th European Biomass Conference 2009, 29th of June-3rd of July 2009, Hamburg, Germany. p 1821-1823.
Details AbstractIn the presented work the fuel quality and basic data about production processes of wood pellets from
all over Europe are investigated. For this purpose pellets producers were interviewed and fuel samples were analysed. Information from 91 companies was evaluated, covering about 50% of the European pellets production capacity, and pellets samples of 51 companies from 18 different countries were examined. It was found, that the raw material for pellets production is mainly taken from local resources. 75% of the plants process soft wood, whereas the use of hard wood is more common in Eastern Europe, Italy, Spain and France. Regarding the fuel properties of the pellets, differences were mainly found with regard to ash content and mechanical durability. In spite of these strong variations, almost all samples fulfilled the requirements according to the respective quality standard declared, and a clear correlation of valid standards and available pellets qualities was observed.
Other papers | 2014
Quantitation of aging products formed in biodiesel during the Rancimat accelerated oxidation test
Flitsch S, Neu PM, Schober S, Kienzl N, Ullmann J, Mittelbach M. Quantitation of aging products formed in biodiesel during the Rancimat accelerated oxidation test. Energy and Fuels. 2014;28(9):5849-56.
External Link Details AbstractBiodiesel (rapeseed oil methyl ester) was aged in a Rancimat device at a temperature of 110°C and an air flow of 10 L/h. Time-resolved analyses applying gas chromatography-flame ionization detection, gas chromatography-mass spectrometry, and ion-exchange chromatography on the formation of aging products were performed. Formic and acetic acid, fatty acids with chain lengths from 5 to 18 carbon atoms, fatty acid methyl esters, and epoxides were quantified. After 12 h of aging, the concentrations of formic and acetic acid were 5600 ± 80 and 1360 ± 80 mg/kg, respectively. Fatty acid concentrations were in the range of <18-4200 mg/kg after 18 h of aging. Linoleic acid methyl ester and linolenic acid methyl ester (19 and 9.1 mass % of the non-aged fuel) were shown to be fully decomposed after 24 and 18 h of aging, respectively. After 51 h of aging, the concentration of oleic acid methyl ester (63 mass % of the non-aged fuel) decreased to 2.2 mass % and trans-epoxy stearic acid methyl ester and cis-epoxy stearic acid methyl ester reached concetrations of 5.9 and 0.7 mass %, respectively. The fuel composition shows only minor changes in early stages of aging, and a strong timely correlation of the formation of aging products with the end of the induction period of fuel was observed. © 2014 American Chemical Society.
Other Publications | 2021
Raising awareness and changing behaviour with the traveling combustion education - The CleanAir II project
Schwabl M. Raising awareness and changing behaviour with the traveling combustion education - The CleanAir II project. IEA Bioenergy End-of-Triennium Conference. December 2021.
DetailsConference presentations and posters | 2009
Reached Developments of Biomass Combustion Technologies and Future Outlook (plenary lecture)
Obernberger I. Reached Developments of Biomass Combustion Technologies and Future Outlook (plenary lecture), 17th European Biomass Conference 2009, 29th of June-3rd of July 2009, Hamburg, Germany. p 20-37.
DetailsPeer reviewed papers | 2016
Reaction mechanisms and multi-scale modelling of lignocellulosic biomass pyrolysis
Anca-Couce, A. Reaction mechanisms and multi-scale modelling of lignocellulosic biomass pyrolysis. Progress in Energy and Combustion Science. Volume 53, March 2016, Pages 41–79.
External Link Details AbstractIn this work about pyrolysis of lignocellulosic biomass, the individual reaction mechanisms of cellulose, hemicellulose and lignin are initially described. The recent advances in the understanding of the fundamental reaction pathways are described, including quantum-mechanical calculations, and the description of pyrolysis as a two-step process, i.e., primary pyrolysis and secondary charring, the effect of the presence of an intermediate liquid compound, and the influence of inorganic species are discussed.
The need to describe biomass pyrolysis as the sum of the contributions of its individual components is then emphasised. The process of determining biomass mass loss kinetics is analysed, and the product composition and heat of reaction that are experimentally obtained during pyrolysis are presented, along with detailed schemes that can be used to predict them.
Finally, it is demonstrated that a multi-scale consideration of pyrolysis on multiple levels – specifically, on molecular, particle and reaction levels – is required to accurately describe biomass pyrolysis. Intra-particle phenomena and particle models are discussed and the reactor level is analysed with a focus placed on fixed bed and fluidised bed pyrolysis. In summary, a list of 10 research focal points that will be important in the future is presented.
Peer reviewed papers | 2022
Real coupling of solid oxide fuel cells with a biomass steam gasifier: Operating boundaries considering performance, tar and carbon deposition analyses
Pongratz G, Subotić V, von Berg L, Schroettner H, Hochenauer C, Martini S, Hauck M, Steinruecken B, Skrzypkiewicz M, Kupecki J, Scharler R, Anca-Couce A. Real coupling of solid oxide fuel cells with a biomass steam gasifier: Operating boundaries considering performance, tar and carbon deposition analyses. Fuel. 15 May 2022.316:123310.
External Link Details AbstractSolid oxide fuel cells are a promising alternative to gas engines for combined heat and power production based on biomass gasification. The technical complexity of realizing gasifier – fuel cell couplings has limited the number of experiments conducted in the past. However, results from such experiments are of high importance for the evaluation of tar thresholds and operating conditions ensuring a stable operation of fuel cells. For the first time, it was possible to demonstrate for dozens of hours the operation of solid oxide fuel cells with real product gas from steam gasification with a steam-to-carbon ratio of 2 and a typical tar content for fluidized bed gasification. Four coupling experiments with industrial-relevant cell designs were conducted, demonstrating a stable operation for 30 h without structural degradation of the anodes for cells with nickel/ceria- and nickel/zirconia-based anodes at 800°C and 850°C, if heavy tars were partially removed (2.8–3.7 g·Nm−3 gravimetric tars). Raw gas operation (4.6–4.8 g·Nm−3 gravimetric tars) led to metal dusting effects on nickel contact meshes and nickel/zirconia-based anodes, whereas nickel/ceria-based anodes were less affected. Carbon deposited on the alumina support in all experiments whereby a change from pyrolytic to graphitic structure could be observed when increasing the temperature from 800°C to 850°C, thus significantly reducing the risk for blockages in the flow channels. Moreover, high tar and benzene conversion rates were observed. Concluding, operating temperatures of 850°C and the removal only of heavy tars can enable stable long-term operation with a tar-laden steam gasifier product gas, even without increasing the steam-to-carbon ratio to values exceeding two.
Other papers | 2019
Real life emission factor assessment for biomass heating appliances at a field measurement campaign in Styria, Austria
Sturmlechner R, Schmidl C, Carlon E, Reichert G, Stressler H, Klauser F, Kelz J, Schwabl M, Kirchsteiger B, Kasper-Giebl A, Höftberger E, Haslinger W. Real life emission factor assessment for biomass heating appliances at a field measurement campaign in Styria, Austria. Air Pollution 2019 - 27th International Conference on Modelling, Monitoring and Management of Air Pollution, Aveiro (oral presentation). June 2019.
External Link Details AbstractBiomass combustion is a major contributor to ambient air pollution. Thus, knowing the real-life emissions of biomass heating systems is crucial. Within the project Clean Air by biomass a field measurement campaign was conducted. 15 biomass heating appliances were tested in households at the end user according to their usual operation. Emission factors for gaseous and particulate emissions, as well as for the genotoxic and carcinogenic substance benzo(a)pyrene, were evaluated and compared to current proposed European and Austrian emission factors used for emission inventories. Moreover, the shares of particles and benzo(a)pyrene in hot and cooled flue gas were determined. Results showed a high variability of emissions in the field. Highest values and ranges occurred for room heaters (TSPtotal: 226 mg/MJ). Biomass boilers showed clearly lower emission factors (TSPtotal: 184 mg/MJ) in the field than room heaters and also than the proposed European and Austrian emission factors, in many cases. Emission factors for tiled stoves showed a similar trend (TSPtotal: 67 mg/MJ). The share of condensable particles in the flue gas was remarkable. Especially benzo(a)pyrene was found mostly in the condensable fraction of the particles.
Peer reviewed papers | 2019
Real-life emission factor assessment for biomass heating appliances at a field measurement campaign in Styria, Austria
Sturmlechner R, Schmidl C, Carlon E, Reichert G, Stressler H, Klauser F, Kelz J, Schwabl M, Kirchsteiger B, Kasper-Giebl A, Höftberger E, Haslinger W. Real-life emission factor assessment for biomass heating appliances at a field measurement campaign in Styria, Austria. WIT Transactions on Ecology and the Environment 2019.236:221-231
External Link Download PDF Details AbstractBiomass combustion is a major contributor to ambient air pollution. Thus, knowing the real-life emissions of biomass heating systems is crucial. Within the project Clean Air by biomass a field measurement campaign was conducted. 15 biomass heating appliances were tested in households at the end user according to their usual operation. Emission factors for gaseous and particulate emissions, as well as for the genotoxic and carcinogenic substance benzo(a)pyrene, were evaluated and compared to current proposed European and Austrian emission factors used for emission inventories. Moreover, the shares of particles and benzo(a)pyrene in hot and cooled flue gas were determined. Results showed a high variability of emissions in the field. Highest values and ranges occurred for room heaters (TSPtotal: 226 mg/MJ). Biomass boilers showed clearly lower emission factors (TSPtotal: 184 mg/MJ) in the field than room heaters and also than the proposed European and Austrian emission factors, in many cases. Emission factors for tiled stoves showed a similar trend (TSPtotal: 67 mg/MJ). The share of condensable particles in the flue gas was remarkable. Especially benzo(a)pyrene was found mostly in the condensable fraction of the particles.
Peer reviewed papers | 2021
Real-life emissions from residential wood combustion in Austria: From TSP emissions to PAH emission profiles, diagnostic ratios and toxic risk assessment
B Kirchsteiger, F Kubik, R Sturmlechner, H Stressler, M Schwabl, M Kistler, A Kasper-Giebl. Real-life emissions from residential wood combustion in Austria: From TSP emissions to PAH emission profiles, diagnostic ratios and toxic risk assessment. Atmospheric Pollution Research. 2021.12:8.
External Link Details AbstractResidential wood combustion is, besides particulate emissions, also linked to emissions of organic compounds, comprising various toxic substances such as polycyclic aromatic hydrocarbons (PAHs). Although, literature data has shown that highest emissions occur during maloperations caused by the user itself, most studies focus on lab-testing not reflecting the situation in the field. This study evaluates the real-life situation in Austria, investigating emissions of total suspended particles (TSP) and particle-bound substances of four manually operated room heaters commonly installed in people's homes. Measurements were conducted within a field measurement campaign realized in the scope of the Clean Air by biomass project. To evaluate the impact of the users' habit two types of combustion experiments were performed, one representing the diversity of possible maloperations and one realized under optimized conditions following a strict optimization protocol. As special focus was laid on PAHs, sampling was realized using a dilution system adapted for the use in the field. Generally, optimization lead to a clear decrease of most compounds (i.e. TSP, OC, EC, PAHs), however, emissions of the anhydrosugar levoglucosan were not affected at all. Total PAH emissions could be clearly reduced, moreover, optimization lead to a shift towards low molecular weight PAHs and thus, less toxic ones, clearly reflected by lower toxicity equivalents. Correlation analysis using the Spearman's rank method showed significantly high correlations among the individual PAH congeners, and rather low ones with other target substances.
Other Publications | 2009
Realisierung einer mit Biomasse befeuerten Mikro-Kraft-Wärme-Kopplung mit thermoelektrischem Generator
Moser, W. Realisierung einer mit Biomasse befeuerten Mikro-Kraft-Wärme-Kopplung mit thermoelektrischem Generator, Doctoral Thesis, Technische Universität Wien, Vienna, Austria, 2009.
DetailsConference presentations and posters | 2009
Reality Check for Agricultural Biofuels
Wopienka E, Friedl G, Haslinger W. Reality Check for Agricultural Biofuels, World Sustainable Energy Days 2009, 25th-27th of February 2009, Wels, Austria.
DetailsConference presentations and posters | 2012
Recent Gas sampling and analysis methods for the determination of condensable gas components in fuel gases and synthesis gases from pyrolysis and gasification
Neubauer Y, Kleinhappl M. Recent Gas sampling and analysis methods for the determination of condensable gas components in fuel gases and synthesis gases from pyrolysis and gasification, 20th European Biomass Conference 2012, 18th-22nd of June 2012, Milano, Italy. p 1095-1096.
Details AbstractA workshop on sampling and analysis of gas impurities (mainly condensables (tar)) in gases from thermochemical conversion processes was held in Berlin at the 19th EU BC+E. Here the outcomes are shortly summarized and the activities in the after course of the workshop are briefly discussed. An international working group formed to further discuss the important topics of analytics in these gas families was formed. Further ongoing and planned activities will be mentioned.
Peer reviewed papers | 2014
Reducing the risk of foaming and decreasing viscosity by two-stage anaerobic digestion of sugar beet pressed pulp
Stoyanova E, Forsthuber B, Pohn S, Schwarz C, Fuchs W, Bochmann G. Reducing the risk of foaming and decreasing viscosity by two-stage anaerobic digestion of sugar beet pressed pulp. Biodegradation. 2014;25(2):277-89.
External Link Details AbstractAnaerobic digestion (AD) of sugar beet pressed pulp (SBPP) is a promising treatment concept. It produces biogas as a renewable energy source making sugar production more energy efficient and it turns SBPP from a residue into a valuable resource. In this study one- and two-stage mono fermentation at mesophilic conditions in a continuous stirred tank reactor were compared. Also the optimal incubation temperature for the pre-acidification stage was studied. The fastest pre-acidification, with a hydraulic retention time (HRT) of 4 days, occurred at a temperature of 55 °C. In the methanogenic reactor of the two-stage system stable fermentation at loading rate of 7 kg VS/m3 d was demonstrated. No artificial pH adjustment was necessary to maintain optimum levels in both the pre-acidification and the methanogenic reactor. The total HRT of the two-stage AD was 36 days which is considerably lower compared to the one-stage AD (50 days). The frequently observed problem of foaming at high loading rates was less severe in the two-stage reactor. Moreover the viscosity of digestate in the methanogenic stage of the two-stage fermentation was in average tenfold lower than in the one-stage fermentation. This decreases the energy input for the reactor stirring about 80 %. The observed advantages make the two-stage process economically attractive, despite higher investments for a two reactor system. © 2013 Springer Science+Business Media Dordrecht.
Conference presentations and posters | 2019
Reduction of ash-realted problems in large-scale biomass combustion systems via resource efficient low-cost fuel additives
Sommersacher P, Kienzl N, Retschitzegger S. Reduction of ash-realted problems in large-scale biomass combustion systems via resource efficient low-cost fuel additives. 27th European Biomass Conference & Exhibition (Poster). 2019.
External Link Details AbstractThe incineration of waste wood is very often associated with ash-related problems (deposits, slagging and corrosion). This leads to short maintenance intervals, which result in significant power generation losses and high downtime costs. To avoid these problems, additives can be used, with particularly cost-effective additives being of great interest. Based on pre-evaluations, the addition of 2% gypsum and 3% coal fly ash was recommended, since an improved ash melting behaviour and reduced risk for high-temperature corrosion can be expected with addition of gypsum and coal fly ash. These additives with the recommended mixing rates were then investigated in a large-scale plant. Extensive investigations were carried out without additive (as a reference), and with the additives focusing on dust formation (aerosols and total dust), deposit formation and the corrosion behaviour of superheaters. These investigations were accompanied by fuel and ash analyses (grate, cyclone and filter). The addition of additives increased the amount of total dust in the flue gas up to 195% and 262% for gypsum and coal fly ash respectively. The chemical analysis of the total dust showed an enrichment of refectory species like Al for coal fly ash and Ca and Mg for gypsum which can positively influence the slagging behaviour. Aerosol measurements showed that the addition of coal fly ash minimised the amount of fine particulate matter, as less alkali metals (K and Na) were released into the gas phase. Gypsum addition increases the SO2 concentrations in the gas phase due to the decomposition of gypsum, as in the combustion chamber about 900°C are present. Due to the preferred sulphation reactions (binding of S to alkali metals) less Cl is bound to alkali metals and therefore the Cl concentrations in the aerosols were lower compared to the reference case. This effect was also found in the deposits sampled at the position of the superheater. Based on the chemical composition of deposits the molar 2S/Cl ratios were determined, which can be used to predict the risk for high temperature corrosion. The analysis data showed that an improvement concerning the high temperature corrosion risk is possible by adding coal fly ash, whereas a significant improvement in case of gypsum additions seems very likely. The measurements carried out so far showed the influence (built-up rate, chemical composition etc.) of the additive application on ash fractions, deposits and dusts. By taking a closer look at the change in chemical compositions of dusts and deposits, additives with an appropriate additivation ratio can be suggested. In case of coal fly ash 3% and in case of gypsum 1% additive related to dry fuel seems to be adequate additive ratios to positively influence the risk of high temperature corrosion and reduce the slagging behaviour.
Conference presentations and posters | 2020
REFAWOOD - Reduction of ash-related problems in large-scale biomass combustion systems via resource efficient low-cost fuel additives
Sommersacher P. REFAWOOD - Reduction of ash-related problems in large-scale biomass combustion systems via resource efficient low-cost fuel additives. 6th Central European Biomass Conference CEBC 2020 (Oral Presentation). 2020.
External Link Download PDF Details AbstractThe incineration of waste wood is very often associated with ash-related problems (deposits, slagging and corrosion). This leads to short maintenance intervals, mainly needed to remove ash depositions, which result in significant power generation losses and high downtime costs. To avoid these problems, additives can be used, with particularly cost-effective additives being of great interest. On the one hand, the purpose of the additives is to reduce the Cl concentration in deposits on heat exchangers, which is the main cause for corrosion. On the other hand, the additives shall increase the ash melting temperature of deposits and hereby reduce deposit formation. In a first step the combustion behaviour of 3 different waste wood mixtures without and with the addition of various low-cost additives such as recycled gypsum, coal fly ash and iron sulphide with two different addition ratios were investigated in a laboratory reactor. Using the laboratory reactor allowed the determination of suitable additives and ratios of additivation for further investigations in the industrial plant. This approach represents a cost-effective and time-saving method for determining suitable additives and ratios of additivation. Based on the investigations carried out, the addition of 2% gypsum and 3% coal fly ash was recommended, since an improved ash melting behaviour can be expected with addition of gypsum and coal fly ash. These additives with the recommended mixing rates were then tested in a large scale CHP plant (a 40 MWth grate furnace with additional injection of wood dust above the grate). Extensive test runs were carried out without additive (as a reference), and with the additives focusing on dust formation (aerosols and total dust), deposit formation and the corrosion behaviour of superheaters. These investigations were accompanied by fuel and ash analyses (grate, cyclone and filter).
Peer reviewed papers | 2018
Reference Shaping for Model-Based Control of Biomass Grate Boilers.
Seeber R, Gölles M, Dourdoumas N, Horn M. Reference Shaping for Model-Based Control of Biomass Grate Boilers. Control Engineering Practice. 2019 Jan;82:173-184. https://doi.org/10.1016/j.conengprac.2018.10.006
External Link Details AbstractAn established control strategy for biomass grate boilers based on a low-order nonlinear model is considered. Under ideal conditions, it achieves decoupled control of desired outputs by means of input–output linearization. The decoupling is gradually reduced and control performance deteriorates when actuator saturation occurs. This may be avoided by appropriately shaping the control strategy’s reference values. This contribution presents a method to do so by solving a sequence of linear programs. Its implementation requires the knowledge of typically unknown limits of mass-flows fed into the plant. An estimation strategy for these limits based on measurable quantities is thus proposed. Experimental data from three different scenarios is presented, in which the reference shaping improves tracking, mitigates wind-up phenomena and reduces emissions, respectively.
Conference presentations and posters | 2012
Reflexions on the existing guideline (and EN) about the sampling and analysis of tar matter from product gas, pyrolysis gas and synthesis gas
Zeisler J, Kleinhappl M, Martini S, Neubauer Y. Reflexions on the existing guideline (and EN) about the sampling and analysis of tar matter from product gas, pyrolysis gas and synthesis gas, 20th European Biomass Conference 2012, 18th-22nd of June 2012, Milano, Italy. p 884-897.
Details AbstractIn the last years sampling at various gasification plants has been performed at Bioenergy2020+. The equipment, which is based on the recommendations of the tar guideline, has been further developed and adjusted to specific needs. For an evaluation of the procedure different parts of the equipment were tested with a new developed gas-generating unit. Most effort has been performed at the absorption of BTXE-S and PAH in 2-propanol. Additionally new characterisation-methods for pyrolysis samples with SPE (Solid Phase Extraction) have been tested and a qualitative identification of main components could be achieved. Furthermore tests for stabilisation and storage of samples were done. The results of the investigations represent an ongoing optimisation-work with the aim of establishing an international working-group which will compile guidelines for sampling organic and inorganic components at gasification and pyrolysis plants with different new online and offline methods. The appendix delivers some useful data about the substances and dynamic precipitation in an investigated impinger step.
Other Publications | 2018
Regelung verfahrens- und energietechnischer Anlagen. Zukünftige Möglichkeiten durch zunehmende Digitalisierung.
Gölles M. Regelung verfahrens- und energietechnischer Anlagen. Zukünftige Möglichkeiten durch zunehmende Digitalisierung. 6. Fachkolloquium, Effiziente und schadstoffarme Verbrennungstechnologien für Biomasse. Präseantion. 10.07.2018.
DetailsConference presentations and posters | 2015
Regulation of land competition in Brazil
Ludwiczek N. Regulation of land competition in Brazil, 23rd European Biomass Conference 2015, 1st-4th of June 2015, Vienna, Austria. (oral presentation)
DetailsConference presentations and posters | 2013
Release of gaseous compounds during torrefaction – results from test runs and modelling
Mehrabian R, Stangl S, Scharler R, Obernberger I, Janisch W, Trattner K. Release of gaseous compounds during torrefaction – results from test runs and modelling, 21st European Biomass Conference and Exhibition 2013, 3rd-7th of June 2013, Copenhagen, Denmark.
Details AbstractMost of the current pyrolysis/torrefaction mechanisms are not able to predict the composition of pyrolysis/torrefaction products. They usually lump the products as permanent gases, liquids (condensable species) and solid residuals. However, the composition of the emitted species is required to predict the calorific value of the torrgas and to model the possible subsequent gas phase reactions and the temperature distribution within the reactor. Therefore, in this work a mechanism from literature is applied for the first time to predict the composition of the torrgas as a combination of twenty typical species. Several experimental data sets from literature are used to evaluate the mechanism. Since the mechanism predicts several relevant species (>1% wt.) in the torrgas for which no experimental data in the literature are available, test runs at a lab-scale packed bed reactor have been performed to achieve more detailed data of torrgas composition for model validation. Among the species for which measured data are available, carbon monoxide and methanol are well predicted. The predictions of carbon dioxide, methane, formaldehyde, acetaldehyde and ethanol are qualitatively correct. The predictions of water vapour, acetic acid, propanal, ethylene and sugar components show deviations. However, yields of solid residual and total emitted gas and tar are well predicted by the mechanism.
Peer reviewed papers | 2024
Release of N-containing compounds during pyrolysis of milk/dairy processing sludge – Experimental results and comparison of measurement techniques
Kwapinska M, Sommersacher P, Kienzl N, Retschitzegger S, Lagler J, Horvat A, Leahy JJ, Release of N-containing compounds during pyrolysis of milk/dairy processing sludge – Experimental results and comparison of measurement techniques. Journal of Analytical and Applied Pyrolysis.2024_178:10639. 10.1016/j.jaap.2024.106391
External Link Details AbstractA dried dairy processing sludge (sludge from wastewater treatment of an effluent from a milk processing plant) was pyrolysed in a single-particle reactor at different temperatures from 400 °C to 900 °C. NH3 and HCN were measured online and offline by means of FTIR as well as by cumulative sampling in impinger bottles (in 0.05 M H2SO4 and 1 M NaOH, respectively) and analysed by photometric method. NO and NO2 were measured online using a nitric oxide analyser while N2O was measured by FTIR. Nitrogen (N) in the sludge and in the remaining char, char-N, was determined. Moreover, tar content in pyrolysis gas was measured and tar-N was determined. The results with respect to N mass balance closure are discussed. The different measurements techniques are compared. For pyrolysis at 520 ℃ and 700 ℃ nitrogen in the gas phase was mainly contained as N2 (36 % and 40 % respectively), followed by NH3 (15 % and 18 %), tar-N (10 % and 9 %), HCN (1 % and 3 %), NO (1 %) and NO2 (0.2 %). The dairy processing sludge has very specific properties with organic-N present predominantly as proteins and a high content of inherent Ca. These characteristics affected the distribution of N. The amount of char-N was higher while the amount of tar-N lower than for sewage sludge from literature, at comparable pyrolysis temperature.
Conference presentations and posters | 2020
Reliability of TGA data for characterization of alternative biomass feedstocks
Retschitzegger S, Kienzl N, Anca-Couce A, Tsekos C, Banks S, Kraia T, Zimbardi F, Funke A, Marques P. Reliability of TGA data for characterization of alternative biomass feedstocks. 6th Central European Biomass Conference, 2020, Graz.
External Link Download PDF DetailsPeer reviewed papers | 2025
Renewable hydrogen production from hydrothermal liquefaction wastewater via aqueous phase reforming: From laboratory to pilot scale
Arlt S, Zoppi G, Hochgerner S, Weber G, Pipitone G, Pirone R, Bensaid S. Renewable hydrogen production from hydrothermal liquefaction wastewater via aqueous phase reforming: From laboratory to pilot scale.2025.103:213*223.
External Link Details AbstractAqueous phase reforming (APR) has been proposed during the last years as a promising technology to produce renewable hydrogen from carbon-laden water fractions. However, only small-scale set-ups have been used for the investigation so far, leading to a gap in technological knowledge. In this work, a multi-component mixture representative of wastewater from lignin-rich hydrothermal liquefaction (HTL) was evaluated at two different scales: a lab-scale facility (30–60 mL/h) to optimize the reaction conditions and, for the first time, a pilot-scale unit (max. 44 L/h) to validate the results. On lab scale, the influence of reaction temperature, weight hourly space velocity and feed concentration on the process performance was investigated using a response surface methodology (RSM) approach via Box-Behnken design. It was found out that temperature was the most important variable to model the reactants conversion, carbon conversion to gas and hydrogen yield, with a significant agreement between the experimental and predicted values in the design space. At pilot scale, the influence of temperature and pressure as well as catalyst stability were investigated. Furthermore, stable operation was demonstrated in a continuous 100 h experiment. A maximum hydrogen yield of 58% and carbon conversion to gas of 54% were achieved at 547 K, 10 g/L organics concentration and 60 mL/gcat‧h. Overall, this study allowed to increase the understanding of APR at the highest technology readiness level available so far, paving the way towards its implementation on industrial scale.
Conference presentations and posters | 2014
Residential Wood Combustion (RWC) -Investigation of user behavior and operating conditions regarding stoves and their impact on emissions and efficiency
Reichert G, Schmidl C, Haslinger W, Moser W, Aigenbauer S, Figl F, Wöhler M. Residential Wood Combustion (RWC) -Investigation of user behavior and operating conditions regarding stoves and their impact on emissions and efficiency, 4th Central European Biomass Conference 2014, 15th-18th of January 2014, Graz, Austria.
Details Abstract
Other papers | 2009
Results and Experiences of Long Term Tests of the Fischer Tropsch Synthesis at the Biomass CHP Güssing
Rauch R. Results and Experiences of Long Term Tests of the Fischer Tropsch Synthesis at the Biomass CHP Güssing, Kraftstoffe der Zukunft 2009, 7. Internationaler Fachkongress für Biokraftstoffe des BBE und der UFOP 2009, 30th of November–1st of December 2009, Berlin, Deutschland.
DetailsPeer reviewed papers | 2020
Robust design of microgrids using a hybrid minimum investment optimization
Pecenak ZK, Stadler M, Mathiesen P, Fahy K, Kleissl J. Robust design of microgrids using a hybrid minimum investment optimization. Applied Energy. 2020;276:115400.
External Link Details AbstractRecently, researchers have begun to study hybrid approaches to Microgrid techno-economic planning, where a reduced model optimizes the DER selection and sizing is combined with a full model that optimizes operation and dispatch. Though providing significant computation time savings, these hybrid models are susceptible to infeasibilities, when the size of the DER is insufficient to meet the energy balance in the full model during macrogrid outages. In this work, a novel hybrid optimization framework is introduced, specifically designed for resilience to macrogrid outages. The framework solves the same optimization problem twice, where the second solution using full data is informed by the first solution using representative data to size and select DER. This framework includes a novel constraint on the state of charge for storage devices, which allows the representation of multiple repeated days of grid outage, despite a single 24-h profile being optimized in the representative model. Multiple approaches to the hybrid optimization are compared in terms of their computation time, optimality, and robustness against infeasibilities. Through a case study on three real Microgrid designs, we show that allowing optimizing the DER sizing in both stages of the hybrid design, dubbed minimum investment optimization (MIO), provides the greatest degree of optimality, guarantees robustness, and provides significant time savings over the benchmark optimization.
Conference presentations and posters | 2014
Rolle und Potenzial der Bioenergie für die Wärmeversorgung der Zukunft
Haslinger W. Rolle und Potenzial der Bioenergie für die Wärmeversorgung der Zukunft, Technologiegespräche Alpbach 2014, 13th-29th of August 2014, Alpbach, Austria.
DetailsConference presentations and posters | 2010
Rotary Kiln Pyrolysis First Results of a 3 MW Pilot Plant
Kern S, Halwachs M, Pröll T, Kampichler G. Rotary Kiln Pyrolysis First Results of a 3 MW Pilot Plant, 18th European Biomass Conference and Exhibiton 2010, 3th-7th May 2010, Lyon, France. p 950-955.
Details AbstractA pyrolysis process can be used to split up the biomass in a volatile fraction poor in undesired substances (Cl, N, S,
Na and K) and a char fraction where these substances are concentrated. In this way cheap biomass can be used for cofiring in existing fossil fuel power stations without the danger of corrosion, deposition, and emission problems. The aim of the project is the development and demonstration of a biomass pretreatment process based on pyrolysis in the temperature range between 450-650 °C to split the energy in the biomass into volatiles with a low content of the above mentioned undesired compounds and char, where most of these pollutants are concentrated. The balance of the system can provide important results, such as the development of the product spectrum by a function of the operating parameters. Based on the results of the pilot plant a scale up to a capacity of 30 MWth fuel input and the connection with the coal fired power plant is currently investigated.
Other papers | 2012
Rotary kiln pyrolysis of straw and fermentation residues in a 3 MW pilot plant – Influence of pyrolysis temperature on pyrolysis product performance
Kern S, Halwachs M, Kampichler G, Pfeifer C, Pröll T, Hofbauer H. Rotary kiln pyrolysis of straw and fermentation residues in a 3 MW pilot plant - Influence of pyrolysis temperature on pyrolysis product performance. J Anal Appl Pyrolysis. 2012;97:1-10.
External Link Details AbstractThe idea of co-firing biomass in an already existing coal-fired power plant could play a major contribution in the reduction of carbon dioxide emissions. Huge amounts of unused biomass in terms of agricultural residues such as straw, which is a cheap and local feedstock, are often available. But due to the high amount of corrosive ash elements (K, Cl, etc.), the residues are usually not suitable for co-firing in a thermal power plant. Therefore, the feedstock is converted by low temperature pyrolysis into gaseous pyrolysis products and charcoal. A 3 MW pyrolysis pilot plant located next to a coal-fired power plant near Vienna was set up in 2008. For the process, an externally heated rotary kiln reactor with a design fuel power of 3 MW is used which can handle about 0.6-0.8 t/h straw. The aim is to investigate the fundamentals for scale-up to the desired size for co-firing in a coal-fired power plant. In addition to the desired fuel for the process, which is wheat straw, a testing series for DDGS was also performed. The high amount of pyrolysis oil in the gas had positive effects on the heating value of the pyrolysis gas. Chemical efficiencies of this pyrolysis pilot plant of up to 67% for pyrolysis temperatures between 450°C and 600°C can be reached. The focus of this work is set on the pyrolysis products and their behavior at different pyrolysis temperatures as well as the performance of the pyrolysis process. © 2012 Elsevier B.V.
Conference presentations and posters | 2010
Rotary kiln pyrolysis- First results of a 3 MW pilot plant
Kern S, Halwachs M, Pröll T, Kampichler G. Rotary Kiln Pyrolysis First Results of a 3 MW Pilot Plant, IFC on IGCC and XtL 2010, 3rd-5th of May 2010, Dresden, Germany.
Details AbstractA pyrolysis process can be used to split up the biomass in a volatile fraction poor in undesired substances (Cl, N, S,
Na and K) and a char fraction where these substances are concentrated. In this way cheap biomass can be used for cofiring in existing fossil fuel power stations without the danger of corrosion, deposition, and emission problems. The aim of the project is the development and demonstration of a biomass pretreatment process based on pyrolysis in the temperature range between 450-650 °C to split the energy in the biomass into volatiles with a low content of the above mentioned undesired compounds and char, where most of these pollutants are concentrated. The balance of the system can provide important results, such as the development of the product spectrum by a function of the operating parameters. Based on the results of the pilot plant a scale up to a capacity of 30 MWth fuel input and the connection with the coal fired power plant is currently investigated.
Other papers | 2017
Rural electrification and capacity expansion with an integrated modeling approach
Hartvigsson E, Stadler M, Cardoso G. Rural electrification and capacity expansion with an integrated modeling approach. Renewable Energy by Elsevier. 2017.
DetailsPeer reviewed papers | 2020
Scale-up methodology for automatic biomass furnaces
Barroso G, Nussbaumer T, Ulrich M, Reiterer T, Feldmeier S. Scale-up methodology for automatic biomass furnaces. Journal of the Energy Institute 2020.93:591-604.
External Link Details AbstractThis work presents a methodology to perform the scale-up of a solid fuel furnace to a higher heat output with maintaining or improving the burn-out quality. As basis to derive the scale-up concept, an example of a 35 kW screw burner for biomass fuels is investigated. Based on the Pi-theorem, the relevant dimensionless parameters are derived and similarity rules for the scale-up are proposed as follows: As initial conditions, the height to diameter ratio of the combustion chamber, the mean Reynolds number in the combustion chamber and the mean square velocity through the combustion chamber shall be kept constant or in the case of the Reynolds number may also increase. Additionally the effective momentum flux ratio between the secondary air injected in the combustion chamber and the gases from the pyrolysis and gasification section also shall be kept constant to maintain the mixing conditions between combustible gases and secondary air. Finally the thermal surface load on the screw also shall be kept constant. The influence of different scale-up approaches on thermal surface load, gas velocity, pressure losses, Reynolds number and height-to-diameter ratio are compared and discussed and a scaling approach to increase the heat output from 35 kW to 150 kW is described. For a theoretical validation of the scale-up, CFD simulations are performed to investigate the predicted pollutant emissions and the pressure loss for the scaled 150 kW furnace.
Other Publications | 2014
Scenedesmus obliquus as Source for Biogas: Anaerobic Digestion of Untreated and Pre-treated Biomass.
Gruber M, Zohar E, Jerney J, Bochmann G, Obbard JP, Schagerl M, Fuchs W, Drosg B. Scenedesmus obliquus as Source for Biogas: Anaerobic Digestion of Untreated and Pre-treated Biomass, 15. Tagung der Sektion Phykologie der DGB 2014, 23rd-26th of February 2014, Stralsund, Germany.
DetailsPeer reviewed papers | 2023
Screw reactors and rotary kilns in biochar production - A comparative review
Moser K, Wopienka E, Pfeifer C, Schwarz M, Seldmayer I, Haslinger W. Screw reactors and rotary kilns in biochar production - A comparative review
External Link Details AbstractOne promising technology in the field of residue valorization is the pyrolytic conversion of biomass to biochar. There are a lot of proven technologies for this task, with many of them being quite distinctive. Biochar has a lot of valuable properties and it shows potential to be applicated in many different fields of industry as a green carbon resource. Thus, as the demand for its production rises, more and more people from different fields share interest in the same technologies and the demand for guidance in form of readily available information increases. Two prominent technologies rather similar in appearance are rotary kilns and screw reactors. Both technologies consist of a long, hollow cylinder and both technologies use some form of longitudinal rotation as a means to transport feedstock. In this review, both technologies are described and their biggest differences and similarities are discussed, all under the aspect of biochar production. In total, 21 unique rotary kilns and 58 unique auger reactors were identified. The paper addresses process specific aspects, like heat supply or residence time, but it also gives an overview on current research and general aspects like scale-up considerations. Differences between both technologies were found in all of these aspects, with some of the most pronounced being the bigger maximum capacities and the greater residence time distributions in rotary kiln pyrolysis. Both technologies are viable candidates for producing biochar on a commercial level, however, literature comparing the influence of the reactor type on biochar properties was very scarce. As a future outlook it is recommended to produce data that can be compared on a quantitative level, so a more accurate assessment of each technologies up- and downsides can be made.
Other Publications | 2023
Second generation biomass gasification: The Syngas Platform Vienna - current status
Fürsatz K, Karel T, Weber G, Kuba M. Second generation biomass gasification: The Syngas Platform Vienna - current status. BEST Center Day. 28 June 2023
Download PDF Details AbstractSteam gasification in a dual fluidized bed (DFB) reactor has already been developed in the power sector from lab- to commercial-scale for woody biomass as feedstock. A trend towards utilizing feedstock of lower quality, such as low-grade biomass, biogenic residues or waste drives the development of the technology in terms of reactor design, gas cleaning and optimizing operation parameters. Additionally, the need for production of sustainable end products more valuable than electricity and heat leads to the embedding of DFB gasification into complete process chains.
Peer reviewed papers | 2014
Seeing about soil — management lessons from a simple model for renewable resources
Lichtenegger K, Schappacher W. Seeing about soil — management lessons from a simple model for renewable resources. International Journal of Modern Physics C. 2014;25(8).
External Link Details AbstractEmploying an effective cellular automata model, we investigate and analyze the build-up and erosion of soil. Depending on the strategy employed for handling agricultural production, in many cases we find a critical dependence on the prescribed production target, with a sharp transition between stable production and complete breakdown of the system.
Strategies which are particularly well-suited for mimicking real-world management approaches can produce almost cyclic behavior, which can also either lead to sustainable production or to breakdown.
While designed to describe the dynamics of soil evolution, this model is quite general and may also be useful as a model for other renewable resources and may even be employed in other disciplines like psychology.
Peer reviewed papers | 2022
Self-Heating of Biochar during Postproduction Storage by O2 Chemisorption at Low Temperatures
Phounglamcheik A, Johnson N, Kienzl N, Strasser C, Umeki K. Self-Heating of Biochar during Postproduction Storage by O2 Chemisorption at Low Temperatures. Energies. 2022.15:380
External Link Details AbstractBiochar is attracting attention as an alternative carbon/fuel source to coal in the process industry and energy sector. However, it is prone to self-heating and often leads to spontaneous ignition and thermal runaway during storage, resulting in production loss and health risks. This study investigates biochar self-heating upon its contact with O2 at low temperatures, i.e., 50–300 °C. First, kinetic parameters of O2 adsorption and CO2 release were measured in a thermogravimetric analyzer using biochar produced from a pilot-scale pyrolysis process. Then, specific heat capacity and heat of reactions were measured in a differential scanning calorimeter. Finally, a one-dimensional transient model was developed to simulate self-heating in containers and gain insight into the influences of major parameters. The model showed a good agreement with experimental measurement in a closed metal container. It was observed that char temperature slowly increased from the initial temperature due to heat released during O2 adsorption. Thermal runaway, i.e., self-ignition, was observed in some cases even at the initial biochar temperature of ca. 200 °C. However, if O2 is not permeable through the container materials, the temperature starts decreasing after the consumption of O2 in the container. The simulation model was also applied to examine important factors related to self-heating. The results suggested that self-heating can be somewhat mitigated by decreasing the void fraction, reducing storage volume, and lowering the initial char temperature. This study demonstrated a robust way to estimate the cooling demands required in the biochar production process.
Conference presentations and posters | 2011
Sensorbasierte Sortierung zur Erzeugung einer Deponiefraktion aus einer MBA-Schwerfraktion - Praxiserfahrungen und Vergleich verschiedener Aufbereitungsalternativen
Meirhofer M, Ragossnig A, Pieber S, Sommer M. Sensorbasierte Sortierung zur Erzeugung einer Deponiefraktion aus einer MBA-Schwerfraktion - Praxiserfahrungen und Vergleich verschiedener Aufbereitungsalternativen, Waste-to-Resources 2011, 24th-27th of May 2011, Hannover, Germany.
Details AbstractThe processing of heterogeneous waste is a major challenge for waste treatment equipment used in mechanical-biological (MB) waste treatment plants. This conference contribution focuses on the technical feasibility and efficiency of different technologies for the processing of a heavy waste fraction from a MB-plant which contains a high portion of high caloric components. The aim is to meet the requirements for waste to be landfilled in Austria. Also economic considerations with regard to the implementation of an additional separation step and the resulting changes in the waste routing are discussed. The processing technologies looked at comprise sensor-based sorting technologies (NIR, X-ray transmission) as well as traditional mechanical density separation technologies such as a jigger and cross-flow air classification.
Other papers | 2010
Sewage Sludge Ash to phosphorus fertiliser (II): variables influencing heavy metal removal during thermochemical treatment
Mattenberger H, Fraissler G, Jöller M, Brunner T, Obernberger I, Herk P, et al. Sewage sludge ash to phosphorus fertiliser (II): Influences of ash and granulate type on heavy metal removal. Waste Manage. 2010;30(8-9):1622-33.
External Link DetailsOther papers | 2008
Sewage Sludge Ash to phosphorus fertiliser: variables influencing heavy metal removal during thermochemical treatment
Mattenberger H, Fraissler G, Brunner T, Herk P, Hermann L, Obernberger I. Sewage sludge ash to phosphorus fertiliser: Variables influencing heavy metal removal during thermochemical treatment. Waste Manage. 2008;28(12):2709-22.
External Link DetailsPeer reviewed papers | 2015
Short term online corrosion measurements in biomass fired boilers. Part 1: Application of newly developed mass loss probe
Retschitzegger S, Gruber T, Brunner T, Obernberger I. Short term online corrosion measurements in biomass fired boilers. Part 1: Application of a newly developed mass loss probe. Fuel Process Technol 2015;137:148-156.
External Link DetailsPeer reviewed papers | 2016
Short term online corrosion measurements in biomass fired boilers. Part 2: Investigation of the corrosion behavior of three selected superheater steels for two biomass fuels
Retschitzegger, S., Gruber, T., Brunner, T., Obernberger, I. Short term online corrosion measurements in biomass fired boilers. Part 2: Investigation of the corrosion behavior of three selected superheater steels for two biomass fuels. Fuel Processing Technology. Volume 142, February 2016, Pages 59-70.
External Link Details AbstractThe high temperature corrosion behavior of the boiler steels 13CrMo4-5 (1.7335), P91 (1.4903) and 1.4541 has been investigated during short-term test runs (~ 500 h) at a biomass fired grate furnace combined with a drop tube. For the test runs performed with 13CrMo4-5 and P91 chemically untreated wood chips have been used as fuel, whereas waste wood has been used for test runs with P91 and 1.4541. Online corrosion probes and a mass loss probe have been used applying a methodology developed in a previous study to correct for a measurement error occurring during short-term measurements with online corrosion probes (mass loss correction). Furthermore, deposit probe measurements have been performed to evaluate the deposit build-up rate and the chemical composition of deposits. SEM/EDX analyses of the corrosion probes have been performed subsequently to the test runs to gain information regarding the chemical composition and structure of the deposits as well as the corrosion layers.
The furnace has been operated at constant load to ensure constant combustion conditions. The flue gas temperature at the probes has been varied between 740 and 900 °C and the probe surface temperature has been varied between 400 and 560 °C in order to determine their influence on the corrosion rate.
General trends determined by the variation of these temperatures were similar for all boiler steels: the corrosion rate increased with increasing flue gas temperature and also with increasing probe surface temperature. For chemically untreated wood chips combustion at low flue gas temperatures (740 °C) the corrosion rates were comparable for 13CrMo4-5 and P91 at all probe surface temperatures. However, at flue gas temperatures of 800 °C and higher P91 showed better corrosion resistance than 13CrMo4-5. For waste wood combustion 1.4541 generally showed a better corrosion resistance than P91.
The mass loss correction of the measurement error occurring in the initial phase resulted in different errors of 55% for 13CrMo4-5 and 32% for P91 for chemically untreated wood chips. For waste wood the mass loss correction resulted in errors of 55% for P91 and 77% for 1.4541. The results from the mass loss determination for the waste wood test runs scattered stronger compared to the wood chips test runs. Therefore, the fits were not that accurate and the error margin was higher. However, the results outline that the mass loss correction is relevant in order to achieve a meaningful comparison of different short-term test runs using online corrosion probes.
Conference presentations and posters | 2014
Sicherheit bei der Lagerung von Pellets
Emhofer W. Sicherheit bei der Lagerung von Pellets, Highlights der Energieforschung VIII - Erneuerbares Heizen und Kühlen 2014, 11th of July 2014, Vienna, Austria
DetailsPeer reviewed papers | 2015
Simultaneous online determination of S, Cl, K, Na, Zn and Pb release from a single particle during biomass combustion Part 1: Experimental setup implementation and evaluation
Sommersacher P, Kienzl N, Brunner T, Obernberger I. Simultaneous online determination of S, Cl, K, Na, Zn and Pb release from a single particle during biomass combustion Part 1: Experimental setup implementation and evaluation. Energy and Fuels. 15 October 2015;29:6734-6746.
External Link Details AbstractThe interest in experimental data regarding thermal fuel decomposition as well as the release behavior of ash-forming elements of biomass fuels for modeling and simulation purposes is continuously increasing. On the basis of combustion experiments with lab-scale reactors and single-particle reactors, integral release data regarding ash-forming vapors can be obtained, whereby the release is calculated on the basis of analysis data of the fuel and the ash residues. At the moment, almost no time-resolved release data of ash-forming elements from single particles exist. Therefore, a single-particle reactor was designed, which has been coupled to an inductively coupled plasma mass spectrometer (ICP-MS). This reactor can be used for targeted experiments in a temperature range of 250–1050 °C under inert, reducing, and oxidizing conditions. With this reactor, it is possible to simultaneously determine the surface and center temperatures of a biomass particle, weight loss of the particle, and flue gas composition. The reactor has been coupled to an ICP-MS through a gas stream that is sufficiently diluted with Ar. First performance tests with pure salts (KCl, NaCl, (NH4)2SO4, ZnCl2, and PbCl2) proved that relevant volatile ash-forming elements can be detected with the ICP-MS. For a further validation of the received signals, combustion tests with Miscanthus pellets have been carried out, whereby the controlled interruption of the experiments has also been investigated. These tests prove that with this system the simultaneous time-resolved determination of S, Cl, K, Na, Zn, and Pb is possible whereby the Cl signal can only be used with restrictions. On the basis of the determined release of ash-forming elements for the entire combustion experiment, a quantification/calibration of the measured intensities has been carried out. The data gained from these tests will provide deeper insights into release processes as well as form a relevant basis for release model development.
Peer reviewed papers | 2016
Simultaneous Online Determination of S, Cl, K, Na, Zn, and Pb Release from a Single Particle during Biomass Combustion. Part 2: Results from Test Runs with Spruce and Straw Pellets
Sommersacher P, Kienzl N, Brunner T, Obernberger I. Simultaneous Online Determination of S, Cl, K, Na, Zn, and Pb Release from a Single Particle during Biomass Combustion. Part 2: Results from Test Runs with Spruce and Straw Pellets. Energy and Fuels. 21 April 2016;30(4): 3428-3440.
External Link Details AbstractTo gain better insight into inorganic element release processes, test runs with a specially designed single particle reactor connected with an inductively coupled plasma mass spectrometer (ICP-MS) have been performed. Relevant combustion related parameters such as mass loss during thermal degradation, temperature development of the particle (surface and center), and composition of released gases were recorded. By coupling the reactor to an ICP-MS, time-resolved release profiles of relevant aerosol forming elements (S, Cl, K, Na, Zn, and Pb) were determined. Targeted and controlled interruptions of the experiments (quenching) after a certain time were performed to validate reactor performance and reliability of the measurements. Test runs with softwood and straw pellets (8 mm in diameter and about 20 mm in length) were performed at reactor temperatures of 700, 850, and 1000 °C under oxidizing conditions (5.6 or 4.2 vol % O2). These test runs have revealed that the release ratios of volatile and semivolatile ash forming elements (S, Cl, K, Na, Zn, and Pb) generally increase as reactor temperatures rise. Moreover, regarding straw, higher Si and Al contents influence the release behavior of K, Na, Zn, and Pb. For K, existing release mechanisms proposed in the literature have been confirmed, and for Na it has been suggested that release mechanisms similar to K prevail. Especially during the starting phase of the experiment, a distinct temperature gradient exists from the surface to the center of the particle. Thus, different conversion phases occur in parallel in different layers of the particle, which has to be considered during the interpretation of the time-resolved release profiles of the main inorganic elements. Furthermore, transport limitations due to the occurrence of molten phases (especially for straw at reactor temperatures of 1000 °C) were obvious and could be directly derived from the online recorded release profiles. The targeted interruption of the ongoing decomposition process (quenching) provided an indication of the validity of the release profiles for S, K, Na, Zn, and Pb. Additionally, these experiments delivered valuable information regarding possible release mechanisms.
Other papers | 2020
Simultaneous state and fuel property estimation in biomass boilers - theory and practice
Zemann C, Gölles M, Horn M. Simultaneous state and fuel property estimation in biomass boilers - theory and practice. 1st Virtual IFAC World Congress. 2020.
External Link Details AbstractA key factor for the further distribution of biomass boilers in modern energy systems is the capability of changing the applied feedstock during normal plant operation. This is only possible with the application of advanced control strategies that utilize knowledge about the state variables and varying fuel properties. However, neither the state variables nor the fuel properties are measurable during plant operation and, thus, need to be estimated. This contribution presents a method for the simultaneous real-time estimation of the state variables and the fuel properties in fixed-bed biomass boilers which is a novel approach in the field of biomass boilers. The method bases on an Extended Kalman Filter using a nonlinear dynamic model and measurement data from the combustion process. The estimated variables are the masses of dry fuel and water in the fuel bed as well as the fuel's bulk density, water content, chemical composition and lower heating value. The proposed method is easy to implement and requires moderate computational effort which increases the potential of its application at actual biomass boilers. The proposed method is verified with simulation studies and by test runs performed at a representative small-scale fixed-bed biomass boiler. The estimation results show a good agreement with the actual values, demonstrating that the proposed method is capable of accurately estimating the biomass boiler's state variables and simultaneously its fuel properties. For this reason, the presented method is a key technology to ensure the further distribution of biomass boilers in modern energy systems.
Peer reviewed papers | 2020
Simultaneous state and fuel property estimation in biomass boilers - theory and practice
Zemann C, Gölles M, Horn M. Simultaneous state and fuel property estimation in biomass boilers - theory and practice. IFAC-PapersOnLine. 2020;53(2):12763-12770. https://doi.org/10.1016/j.ifacol.2020.12.1920
External Link Details AbstractA key factor for the further distribution of biomass boilers in modern energy systems is the capability of changing the applied feedstock during normal plant operation. This is only possible with the application of advanced control strategies that utilize knowledge about the state variables and varying fuel properties. However, neither the state variables nor the fuel properties are measurable during plant operation and, thus, need to be estimated. This contribution presents a method for the simultaneous real-time estimation of the state variables and the fuel properties in fixed-bed biomass boilers which is a novel approach in the field of biomass boilers. The method bases on an Extended Kalman Filter using a nonlinear dynamic model and measurement data from the combustion process. The estimated variables are the masses of dry fuel and water in the fuel bed as well as the fuel’s bulk density, water content, chemical composition and lower heating value. The proposed method is easy to implement and requires moderate computational effort which increases the potential of its application at actual biomass boilers. The proposed method is verified with simulation studies and by test runs performed at a representative small-scale fixed-bed biomass boiler. The estimation results show a good agreement with the actual values, demonstrating that the proposed method is capable of accurately estimating the biomass boiler’s state variables and simultaneously its fuel properties. For this reason, the presented method is a key technology to ensure the further distribution of biomass boilers in modern energy systems.
Peer reviewed papers | 2019
Single large wood log conversion in a stove: Experiments and modelling
Anca-Couce A, Caposciutti G, Gruber T, Kelz J, Bauer T, Hochenauer C, Scharler R. Single large wood log conversion in a stove: Experiments and modelling. Renewable Energy 2019.143:890-897.
External Link Details AbstractNatural draft wood log stoves for residential bioheat production are very popular due to the low fuel costs, the ecological aspect of a renewable energy source and the visual appeal of the flame. However, they have rather high pollutant emissions, specially of unburnt products. The description of large wood logs conversion in stoves needs to be improved to allow a process optimization which can reduce these emissions. The transient conversion of a single wood log in a stove is experimentally investigated with test runs quenching the log after defined time intervals and measuring the flue gas composition and temperatures in the log and stove. The experiments have been described with a volumetric single particle model, which predicts with good accuracy the log conversion until a time of around 30 min, when pyrolysis is almost ending. At that point, log fragmentation takes place and smaller fragments are detached from the log falling onto the bed of embers. Despite the increase in external surface area, char oxidation takes place at a moderate rate. This last stage of wood log conversion in a stove is the most challenging to model. Finally, preliminary recommendations are provided for reducing CO emissions in wood log stoves.
Peer reviewed papers | 2021
Single Pellet Combustion of Sewage Sludge and Agricultural Residues with a Focus on Phosphorus
Häggström G, Hannl TK, Hedayati A, Kuba M, Skoglund N, Öhman M. Single Pellet Combustion of Sewage Sludge and Agricultural Residues with a Focus on Phosphorus. Energy & Fuels. 8 June 2021.
External Link Details AbstractRecycling of phosphorus in combination with increased utilization of bioenergy can mitigate material and global warming challenges. In addition, co-combustion of different fuels can alleviate ash-related problems in thermal conversion of biomass. The aim of this study is to investigate the ash transformation reactions of mainly P in co-combustion of P-rich sewage sludge (SS) with K-rich sunflower husks (SH) and K- and Si-rich wheat straw (WS). Single pellets of 4 mixtures (10 and 30 wt % SS in WS and 15 and 40 wt % SS in SH) and pure SS were combusted in an electrically heated furnace at process temperatures relevant for fluidized bed combustion (800 and 950 °C). Collected ash fractions were analyzed by inductively coupled plasma techniques, ion chromatography, scanning electron microscopy–energy-dispersive X-ray spectroscopy, and X-ray diffraction. Thermodynamic equilibrium calculations were performed to interpret the results. Over 90% of K and P was found to be captured within the residual ash with 30–70% P in crystalline K-bearing phosphates for mixtures with low amounts of SS (WSS10 and SHS15). The significant share of K and P in the amorphous material could be important for P recovery. For the lower percentage mixtures of SS (WSS10 and SHS15), P in crystalline phases was mainly found in K-whitlockite and CaKPO4. For the higher percentage SS mixtures, most of P was found in whitlockites associated with Fe and Mg, and no crystalline phosphates containing K were detected. For P recovery, co-combustion of the lower SS mixtures is favorable, and they are suggested to be further studied concerning the suitability for plant growth.
Other Publications | 2023
Smart Control of Coupled District Heating Networks
Kaisermayer V, Muschick D, Gölles M, Horn M. Smart Control for Couled District Heating Networks. BEST Center Day. 28 June 2023
Download PDF Details AbstractDistrict heating (DH) networks have the potential for intelligent integration and combination of renewable energy sources, waste heat, thermal energy storage, heat consumers, and coupling with
other sectors. For growing networks in close geographical proximity, often the possibility arises to couple them using bidirectional heat exchangers, possibly unlocking synergies and reducing costs for the consumers. Each DH network may consist of producers, consumers and thermal energy storage (TES) devices. Often, each of the coupled DH networks will be already controlled via low-level controllers. Hence, a high-level control approach is needed, that coordinates the heat exchange between the
networks and takes renewable energy sources and the TES capacities in each network into account. These supervisory controllers are generally referred to as energy management systems (EMS).
Peer reviewed papers | 2022
Smart control of interconnected district heating networks on the example of “100% Renewable District Heating Leibnitz”
Kaisermayer V, Binder J, Muschick D, Beck G, Rosegger W, Horn M, Gölles M, Kelz J, Leusbrock I. Smart control of interconnected district heating networks on the example of “100% Renewable District Heating Leibnitz”. Smart Energy. 2022 Apr 7. 100069. https://doi.org/10.1016/j.segy.2022.100069
External Link Details AbstractConference presentations and posters | 2019
Smart Logwood Boiler - A holistic approach for improving the efficiency of residential heating systems. 27th European Biomass Conference & Exhibition.
Zemann C, Deutsch M, Zlabinger S, Hofmeister G, Gölles M, Horn M. Smart Logwood Boiler - A holistic approach for improving the efficiency of residential heating systems. 27th European Biomass Conference & Exhibition. Lisbon. 2019. (Oral presentation, 27.05.2019).
DetailsConference presentations and posters | 2019
Smart Logwood Boiler – A holistic approach for improving the efficiency of residential heating systems
Zemann C, Deutsch M, Zlabinger S, Hofmeister G, Gölles M, Horn M. Smart Logwood Boiler – A holistic approach for improving the efficiency of residential heating systems. 27th European Biomass Conference & Exhibition (Oral Presentation). May 2019.
DetailsOther Publications | 2023
Smart Microgrid Controller and Microgrid Research Laboratory
Stadler M, Aigenbauer S, Mansoor M, Oberbauer C, Houben N, Liedtke P, Sturmlechner R, Maier C, Alavi F, Haas R. Smart Microgrid Controller and Microgrid Research Laboratory. BEST Center Day. 28 June 2023
Download PDF Details AbstractTo ensure that energy is optimally used on site in local energy grids/microgrids and to achieve cost and/or emission reduction targets, the technologies are controlled by predictive and adaptive microgrid controllers. Based on realtime measurement data as well as load, generation, market and weather forecasts, the optimal deployment plan for the local energy grid is thus calculated using mathematical
optimization algorithms. Synergies of different technologies and sectors (electricity, heating, cooling, mobility, etc.) are taken into account, resulting in high energy efficiency in the system.
Other Publications | 2023
Social Sciences and Humanities (SSH) at BEST
Enigl M, Dißauer C, Matschegg D, Sonnleitner A, Strasser C. Social Sciences and Humanities (SSH) at BEST. BEST Center Day. 28 June 2023
Download PDF DetailsOther Publications | 2024
Social Sciences and Huminaties (SSH) at BEST
Enigl M, Dißauer C, Matschegg D, Sonnleitner A, Strasser C. Social Sciences and Humanities (SSH) at BEST. Centre's Day 2024.
Download PDF DetailsConference presentations and posters | 2012
Sofc‐field tests with Biomass gasification derived product gas for the evaluation of stationary BIG‐SOFC‐CHP‐concepts
Martini S. Sofc‐field tests with Biomass gasification derived product gas for the evaluation of stationary BIG‐SOFC‐CHP‐concepts, 5th international Freiberg Conference on IGCC & XtL 2012, 21st-24th of May 2012, Leipzig, Germany. (oral presentation)
DetailsConference presentations and posters | 2012
Sofc‐field tests with Biomass gasification derived product gas for the evaluation of stationary BIG‐SOFC‐CHP‐concepts
Martini S. Sofc‐field tests with Biomass gasification derived product gas for the evaluation of stationary BIG‐SOFC‐CHP‐concepts, 5 th international Freiberg Conference on IGCC & XtL Technologies 2012, 21st-24th of May 2012, Freiberg, Germany.
DetailsOther papers | 2020
Soft-Sensor for the on-line estimation of the flue gas mass flow in biomass boilers with additional monitoring of the heat exchanger fouling
Niederwieser H, Zemann C, Gölles M, Reichhartinger M. Soft-Sensor for the On-Line Estimation of the Flue Gas Mass Flow in Biomass Boilers with Additional Monitoring of the Heat Exchanger Fouling. In Proceedings of the 28th European Biomass Conference and Exhibition 2020 (eEUBCE 2020). 2020. p. 280 - 284
Details AbstractThe flue gas mass flow is one of the fundamental quantities of the combustion process in biomass boilers. Since it directly relates to the enthalpy flow entering the heat exchanger, its knowledge is highly advantageous for a sophisticated load control of the biomass boiler. It also includes information regarding the primary and secondary air mass flows as well as the mass flows of potentially occurring leakage air and thermally decomposed fuel. However, in practical application it is not possible to obtain a reliable measurement of the flue gas mass flow. For this reason, this work presents a soft-sensor for the on-line estimation of the flue gas mass flow in biomass boilers. The approach is robust against fouling of the relevant boiler components and is based on standard measurements which are typically available in biomass boilers. In addition, the soft-sensor offers the possibility of monitoring the degree of heat exchanger fouling.
Other Publications | 2022
Solar goes Digital: Wie Solarwärme selbstlernende Algorithmen nutzt (Austria Solar Webinar 26)
Unterberger V. Solar goes Digital: Wie Solarwärme selbstlernende Algorithmen nutzt (Austria Solar Webinar 26). Online am 11.05.2022.
External Link Download PDF DetailsPeer reviewed papers | 2022
Solid oxide fuel cell operation with biomass gasification product gases: Performance- and carbon deposition risk evaluation via a CFD modelling approach
Pongratz G, Subotić V, Hochenauer C, Scharler R, Anca-Couce A. Solid oxide fuel cell operation with biomass gasification product gases: Performance- and carbon deposition risk evaluation via a CFD modelling approach. 1 April 2022. 244.
External Link Details AbstractSolid oxide fuel cell (SOFC) models used in the past for biomass-to-power plant simulations are limited in their predictability of the carbon deposition risk. In this work, industrial-relevant cell designs were modeled in 2D-CFD considering detailed reaction kinetics which allowed more accurate performance simulations and carbon deposition risk assessments. Via a parametric study, the influence of varying cell operating conditions on the cell performance and carbon deposition risk was quantified when utilizing product gases from steam- and air gasification with varying steam addition. Considering the results from this parameter study and carbon deposition risk assessment, recommendations for promising gasifier-SOFC configurations and cell operating points for stable long-term operation are presented. For smaller-scale biomass-to-power systems, the utilization of product gas from air gasification in anode supported cells with Ni/zirconia-based anode can be recommended, with only moderate steam dilution of the product gas at 750°C cell operating temperature. For larger scales, steam gasification might be meaningful, offering a generally higher electrical efficiency and power output in fuel cells than air gasification. However, a higher risk for carbon deposition could be determined in comparison to air gasification. Hence, a cell temperature of 850°C besides the use of cells with Ni/ceria-based anodes is recommended.
Conference presentations and posters | 2015
Sommersacher P, Kienzl N, Brunner T, Obernberger I
Sommersacher P, Kienzl N, Brunner T, Obernberger I. Online determination of the release of inorganic elements using a single particle reactor coupled with an ICP-MS, 23rd European Biomass Conference 2015, 1st-4th of June 2015, Vienna, Austria. (oral presentation)
DetailsPeer reviewed papers | 2017
Sorghum, a sustainable feedstock for biogas production? Impact of climate, variety and harvesting time on maturity and biomass yield
Wannasek L Ortner M Amon B Amon T. Sorghum, a sustainable feedstock for biogas production? Impact of climate, variety and harvesting time on maturity and biomass yield. BIOMASS BIOENERG. 2017; 106: 137-145
External Link DetailsConference presentations and posters | 2019
Spectroscopic in situ methods for the evaluation of the active centers on ash-layered bed materials from gasification in a fluidized bed reactor
Chlebda D, Aziaba K, Janisch D, Kuba M, Hofbauer H, Łojewska J. Spectroscopic in situ methods for the evaluation of the active centers on ash-layered bed materials from gasification in a fluidized bed reactor. ICPS 2019
DetailsOther papers | 2017
Startups in Kalifornien – Kollaborationsmodell im Energiebereich
Stadler M., Temper M., Haslinger W. Startups in Kalifornien – Kollaborationsmodell im Energiebereich. Impulsreferat Energy.Inc.Ubator, Start-ups als Katalysator in F&E für marktfähige Energiesystemlösungen. Co-Creation-Workshop. Bundesministerium für Verkehr, Innovation und Technologie. Österreich, 22. September 2017.
DetailsOther papers | 2015
State of the art biomass gasification for CHP production – the Ulm plant
Kirnbauer F, Maierhans F, Kuba M, Hofbauer H. State of the art biomass gasification for CHP production – the Ulm plant. Regatec 2015. 7-8 May 2015, Barcelona, Spain.
External Link DetailsOther papers | 2017
State of the art dual fluidized bed gasification of biomass in industrial scale
Kuba M, Kirnbauer F, Hofbauer H. State of the art dual fluidized bed gasification of biomass in industrial scale. 5th Central European Biomass Conference (oral presentation). January 2017, Graz, Austria.
DetailsConference presentations and posters | 2012
State-of-the-art and assessment of filter technologies for residential biomass combustion systems
Obernberger I. State-of-the-art and assessment of filter technologies for residential biomass combustion systems, IEA Bioenergy Conference 2012, 13th-15th of November 2012, Vienna, Austria.
Details