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Other Presentations | 2012

Zustandsschätzung einer Biomassefeuerungsanlage und deren modellbasierte Regelung

Seeber, R. Zustandsschätzung einer Biomassefeuerungsanlage und deren modellbasierte Regelung, Master Thesis, Technische Universität Graz, Graz, Austria, 2012.

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Die Verbrennung fester Biomasse gewinnt als nachhaltige Form der Energienutzung zunehmend an Bedeutung. Dabei stellt die Forderung nach einem schadstoffarmen Betrieb von Biomassefeuerungsanlagen bei möglichst hohem Wirkungsgrad eine Herausforderung an deren Regelung dar. Ziel dieser Arbeit ist die Untersuchung und Verbesserung eines existierenden, modellbasierten Regelungskonzepts, welches die Methode der Eingangs-Ausgangslinearisierung zur Regelung sowie einen Erweiterten Kalmanfilter zur Zustandsschätzung vorsieht. Die Arbeiten wurden in Kooperation mit dem Kompetenzzentrum Bioenergy 2020+ anhand einer Versuchsanlage (Flachschubrostfeuerung mit einer Kesselnennleistung von 180 kW) durchgeführt. Dabei lassen sich eine Reihe von Störeinflüssen identifizieren, unter anderem etwa die bei dieser Anlage besonders stark ausgeprägten Schwankungen des abgebauten Brennstoffs. Die geeignete Berücksichtigung dieser Störeinflüsse im Kalmanfilter durch Formfilter wird untersucht. Ebenso erfolgt die Modellierung von variablen Totzeiten und Sensordynamiken, die bei der Messung einzelner Größen auftreten, durch zusätzliche Sensormodelle. Auf Basis dieser Ergebnisse wird ein neuer Kalmanfilter vorgeschlagen und implementiert. Die auftretenden Störeinflüsse führen bei der exakt linearisierten Strecke zu einer Abweichung vom geforderten linearen Übertragungsverhalten. Daher wird auch der Regler dahingehend modifiziert, dass die vom Kalmanfilter rekonstruierten Störgrößen bei der Ermittlung des nichtlinearen Zustandsregelgesetzes verwendet werden. Das modifizierte Regelungskonzept wurde abschließend an der untersuchten Anlage implementiert und experimentell verifiziert. Dabei wurden gegenüber der ursprünglichen Regelung eine deutliche Verbesserung bei der Stabilisierung von Vorlauf- und Sekundärzonentemperatur sowie eine geringere Abweichung des Verbrennungsluftverhältnisses im Brennstoffbett vom vorgegebenen Sollwert erzielt.


Conference contributions | 2010

Wooden Biofuels in Europe – Quantities and Corrosion Relevant Characteristics.

Schmidl C, Humel S, Haslinger W, Friedl G. Wooden Biofuels in Europe – Quantities and Corrosion Relevant Characteristics, 18th European Biomass Conference 2010, 3rd-7th of May 2010, Lyon, France. p 308-315.

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Contributions to trade journals | 2014

Wood Gas Processing To Generate Pure Hydrogen Suitable for PEM Fuel Cells

Fail S, Diaz N, Benedikt F, Kraussler M, Hinteregger J, Bosch K, et al. Wood gas processing to generate pure hydrogen suitable for PEM fuel cells. ACS Sustainable Chemistry and Engineering. 2014;2(12):2690-8.

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A test campaign was carried out to generate renewable hydrogen based on wood gas derived from the commercial biomass steam gasification plant in Oberwart, Austria. The implemented process consisted of four operation units: (I) catalyzed water-gas shift (WGS) reaction, (II) gas drying and cleaning in a wet scrubber, (III) hydrogen purification by pressure swing adsorption, and (IV) use of the generated biohydrogen (BioH2) in a proton exchange membrane (PEM) fuel cell. For almost 250 h, a reliable and continuous operation was achieved. A total of 560 (Ln dry basis (db))/h of wood gas were extracted to produce 280 (Ln db)/h of BioH2 with a purity of 99.97 vol %db. The catalyzed WGS reaction enabled a hydrogen recovery of 128% (nBioH2)/(nH2,wood gas) over the whole process chain. An extensive chemical analysis of the main gas components and trace components (sulfur, CxHy, and ammonia) was carried out. No PEM fuel cell poisons were measured in the generated BioH2. The only detectable impurities in the product were 0.02 vol %db of O2 and 0.01 vol %db of N2. © 2014 American Chemical Society.


Conference Papers | 2017

Wasserstoff aus Biomasse - Stand der Technik und Perspektiven

Hofbauer H, Bosch K, Kraussler M. Wasserstoff aus Biomasse - Stand der Technik und Perspektiven. 5th Central European Biomass Conference (oral presentation). January 2017, Graz, Austria.

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Conference contributions | 2020

Virtual biomass combustion plant

Schulze K, Virtual biomass combustion plant. 6th Central European Biomass Conference, 22-24 January 2020, Graz.

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Conference contributions | 2012

Verwertung von Reststoffen aus der Lebensmittelproduktion zur Gewinnung von Prozessenergie.

Drosg B, Ortner M, Bochmann G. Verwertung von Reststoffen aus der Lebensmittelproduktion zur Gewinnung von Prozessenergie, Lebensmittel-Cluster Oberösterreich „ Strom - Wärme - Kälte - Wege zum energieeffizienteren Lebensmittelbetrieb“ 2012, 21th of March 2012, Linz, Austria.

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Conference contributions | 2012

Vergleichsanalyse der Vergasung eines biogen und fossil angereicherten EBS

Sommer M, Ragoßnig AM, Kleinhappl M. Vergleichsanalyse der Vergasung eines biogen und fossil angereicherten EBS, DepoTech 2012, 6th-9th of October 2012, Leoben, Austria.

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Peer Reviewed Scientific Journals | 2015

Ventilation of Carbon Monoxide from a Biomass Pellet Storage Tank - A Study of the Effects of Variation of Temperature and Cross-Ventilation on the Efficiency of Natural Ventilation

Emhofer W, Lichtenegger K, Haslinger W, Hofbauer H, Schmutzer-Roseneder I, Aigenbauer S, et al. Ventilation of carbon monoxide from a biomass pellet storage tank - A study of the effects of variation of temperature and cross-ventilation on the efficiency of natural ventilation. Ann Occup Hyg. 2015;59(1):79-90.

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Wood pellets have been reported to emit toxic gaseous emissions during transport and storage. Carbon monoxide (CO) emission, due to the high toxicity of the gas and the possibility of it being present at high levels, is the most imminent threat to be considered before entering a pellet storage facility. For small-scale (<30 tons storage capacity) residential pellet storage facilities, ventilation, preferably natural ventilation utilizing already existing openings, has become the most favored solution to overcome the problem of high CO concentrations. However, there is little knowledge on the ventilation rates that can be reached and thus on the effectiveness of such measures. The aim of the study was to investigate ventilation rates for a specific small-scale pellet storage system depending on characteristic temperature differences. Furthermore, the influence of the implementation of a chimney and the influence of cross-ventilation on the ventilation rates were investigated. The air exchange rates observed in the experiments ranged between close to zero and up to 8 m3h-1, depending largely on the existing temperature differences and the existence of cross-ventilation. The results demonstrate that implementing natural ventilation is a possible measure to enhance safety from CO emissions, but not one without limitations. © 2014 © The Author 2014. Published by Oxford University Press on behalf of the British Occupational Hygiene Society.


Contributions to trade journals | 2012

Variation of Feedstock in a Dual Fluidized Bed Steam Gasifier ‐ Influence on Product Gas, Tar Content and Composition

Schmid JC, Wolfesberger U, Koppatz S, Pfeifer C, Hofbauer H. Variation of feedstock in a dual fluidized bed steam gasifier-influence on product gas, tar content, and composition. Environmental Progress and Sustainable Energy. 2012;31(2):205-15.

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A steam blown dual fluidized bed gasification plant was used to yield a nitrogen (N 2) free product gas (synthesis gas) from various biomass fuels. In addition to the variation of process parameters like temperature, steam to carbon ratio, fluidization rate, and the influence of different bed materials, various feedstock inputs affected the generation of the product gas. This study focuses on the gasification of different biomass feedstock. The variation of biomass implies wood chips, wood pellets, sewage sludge pellets, and straw pellets. The chosen evaluated experimental results are all gained from the uniformly operated "classical" 100 kW "DUAL FLUID" gasifier at Vienna University of Technology at constant gasification temperatures between 800°C and 810°C. In the "classical" design, the gasification reactor is a bubbling fluidized bed. The composition and ash melting behavior of each feedstock is displayed, as well as the ranges of the product gas compositions generated. Beside the main gaseous product gas components, typical content ranges of dust and char are highlighted. The content and composition of tar in the product gas is discussed. Further it is possible to present gravimetrical and gas chromatography coupled with mass spectrometry measured tar values. Not less than five significant component-groups of tar will also be outlined for each feedstock. © 2012 American Institute of Chemical Engineers (AIChE).


Conference contributions | 2010

Valorisation of low grade Biomass to substitute fossil Fuels in a thermal Power Plant

Kern S, Halwachs M, Hofbauer H, Kampichler G. Valorisation of low grade Biomass to substitute fossil Fuels in a thermal Power Plant, WasteEng 2010, 17th-19th of May 2010, Peking, China.

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Minimizing carbon dioxide emissions whereas keeping up the high living standard of today is only possible by increasing the efficiency of energy consumption and the change to a mix of renewable fuels. Huge amounts of unused biomass in terms of agricultural residues like straw, that is a cheap and local feedstock, are often available. But as a reason of the high amount of corrosive ash elements (K, Cl, S), the residues are not suitable for co-firing in a thermal power plant. Therefore the feedstock is converted by low temperature pyrolysis into pyrolysis gases and charcoal. The aim of this work is to obtain fundamentals for an advanced pyrolysis model approach by the results of the pilot plant for co-firing the pyrolysis gases in a thermal power plant. A 3 MW pyrolysis pilot plant is being operated since 2008. For the process, an externally heated rotary kiln reactor with a design fuel power of 3 MW is used. Several mass and energy balances have been calculated based on measured plant data for different operating points of the pilot plant. The high amount of pyrolysis oil in the gas has positive effects to the heating value of the pyrolysis gases. As a reason of that, cold gas efficiencies of more than 70 % are possible. Based on these results, a scale up to a next scale pyrolysis reactor with a capacity of 30 MWth fuel input is currently investigated.


Conference contributions | 2020

Valorisation of industrial by-products from the pulp&paper and rendering industry

Ortner M, Valorisation of industrial by-products from the pulp&paper and rendering industry. 6th Central European Biomass Conference, 22-24 January 2020, Graz.

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Contributions to trade journals | 2011

Validation of flow simulation and gas combustion sub-models for CFD-based prediction of NOx formation in biomass grate furnaces

Zahirović S, Scharler R, Kilpinen P, Obernberger I. Validation of flow simulation and gas combustion sub-models for the CFD-based prediction of NOx formation in biomass grate furnaces. Combustion Theory and Modelling. 2011;15(1):61-87.

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Contributions to trade journals | 2010

Validation of flow simulation and gas combustion sub-models for CFD-based prediction of NOx formation in biomass grate furnaces

Zahirović S, Scharler R, Kilpinen P, Obernberger I. Validation of flow simulation and gas combustion sub-models for the CFD-based prediction of NOx formation in biomass grate furnaces. Combustion Theory and Modelling. 2011;15(1):61-87.

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While reasonably accurate in simulating gas phase combustion in biomass grate furnaces, CFD tools based on simple turbulence-chemistry interaction models and global reaction mechanisms have been shown to lack in reliability regarding the prediction of NOx formation. Coupling detailed NOx reaction kinetics with advanced turbulence-chemistry interaction models is a promising alternative, yet computationally inefficient for engineering purposes. In the present work, a model is proposed to overcome these difficulties. The model is based on the Realizable k-ε model for turbulence, Eddy Dissipation Concept for turbulence-chemistry interaction and the HK97 reactionmechanism. The assessment of the sub-models in terms of accuracy and computational effort was carried out on three laboratory-scale turbulent jet flames in comparison with the experimental data. Without taking NOx formation into account, the accuracy of turbulence modelling and turbulence-chemistry interaction modelling was systematically examined on Sandia Flame D and Sandia CO/H2/N2 Flame B to support the choice of the associated models. As revealed by the Large Eddy Simulations of the former flame, the shortcomings of turbulence modelling by the Reynolds averaged Navier-Stokes (RANS) approach considerably influence the prediction of the mixing-dominated combustion process. This reduced the sensitivity of the RANS results to the variations of turbulence-chemistry interaction models and combustion kinetics. Issues related to the NOx formation with a focus on fuel bound nitrogen sources were investigated on a NH3-doped syngas flame. The experimentally observed trend in NOx yield from NH3 was correctly reproduced by HK97, whereas the replacement of its combustion subset by that of a detailed reaction scheme led to a more accurate agreement, but at increased computational costs. Moreover, based on results of simulations with HK97, the main features of the local course of the NOx formation processes were identified by a detailed analysis of the interactions between the nitrogen chemistry and the underlying flow field. © 2011 Taylor & Francis.


Conference Papers | 2015

Validation of a Kinetic Model for the Catalyzed Water Gas Shift Reaction Applying a Fe/Cr Catalyst Processing Wood Gas from Biomass Steam Gasification

Kraussler M, Fail S, Plaza Quevedo A, Cortes Guerro JA, Rauch R, Hofbauer H. Validation of a Kinetic Model for the Catalyzed Water Gas Shift Reaction Applying a Fe/Cr Catalyst Processing Wood Gas from Biomass Steam Gasification. 23rd European Biomass Conference & Exhibition (Poster). June 2015, Vienna, Austria.

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Peer Reviewed Scientific Journals | 2015

Use of Hazelnut's Pruning to Produce Biochar by Gasifier Small Scale Plant

Colantoni A, Longo L, Evic N, Gallucci F, Delfanti L. Use of Hazelnut‟s Pruning to Produce Biochar by Gasifier Small Scale Plant. International Journal of Renewable Energy Research. 2015;5(3):873-878.

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Biochar is the product of biomass pyrolysis and gasification. One of the possible application of this product is certainly in agronomic sector, as soil amendment. However biochar use in Italy is subordinated to insert this product in fertilizer list, which biochar could be commercialized with. The aim of this paper is to know the biochar from gasification process (using an Imbert downdraft prototype), in particular investigating its potentiality as soil amendment in terms of European and Italian regulations and in terms of physical and chemical characterizations.


Conference Papers | 2017

Upscaling and Operation of a Biomass Derived Fischer-Tropsch Pilot Plant Producing 1 Barrel Per Day

Loipersböck J, Weber G, Rauch R, Gruber H, Groß P, Hofbauer H. Upscaling and Operation of a Biomass Derived Fischer-Tropsch Pilot Plant Producing 1 Barrel Per Day. 25th European Biomass Conference & Exhibition (oral presentation). June 2017, Stockholm, Sweden.

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Other Presentations | 2013

Untersuchung von Wirbelschichtbettmateralien mittels einer Kinetikapparatur

Yildiz, B. Determination of effects of different bed materials on steam reforming for tar reduction, Master Thesis, Vienna University of Technology, Vienna, Austria, 2013.

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Other Presentations | 2013

Untersuchung verschiedener Zugverhältnisse auf die Praxisrelevanz der Prüfung von Scheitholzöfen nach EN 13240

Stressler, H. Untersuchung verschiedener Zugverhältnisse auf die Praxisrelevanz der Prüfung von Scheitholzöfen nach EN 13240, Bachelor Thesis, FH Oberösterreich, Wels, Österreich, 2013.

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Other Presentations | 2008

Untersuchung der Staubemissionen einer Prototyp Strohpelletsfeuerung, sowie Ermittlung des Potentials einer Emissionsreduktion durch einen Brennwertwärmetauscher mit Wäscher

Schwabl, M. Untersuchung der Staubemissionen einer Prototyp Strohpelletsfeuerung, sowie Ermittlung des Potentials einer Emissionsreduktion durch einen Brennwertwärmetauscher mit Wäscher, Master Thesis, Technische Universität Wien, Vienna, Austria, 2008.

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The primary energy consumption world-wide is rising constantly. Therefore it is necessary to open up renewable resources for energy production. Besides wood, the application of agricultural resources and residuals for energy production is possible, also within the range of small scale combustion units. These fuels still pose a challenge, concerning gaseous and particulate emissions. This work examines the application of straw pellets in a small scale combustion unit. Gaseous and particulate emissions, as well as the separation eciency of a secondary heat exchanger with scrubber were investigated. Compared with wood-like fuels a strong slagging of the combustion chamber could be determined. Gaseous emissions as NOx, SO2 and HCl, as well as the emission of particles were clearly higher than with combustions of wood. The gaseous emissions were below the considered limit value for other biogenous fuels after Art. 15 a B-VG 2007 [1]. The burnout of the gaseous phase, which can be evaluated by the emission of CO, was always good and comparable with the combustion of wood.
Using a secondary heat exchanger with scrubber (Hydrocube R of the company Schräder ) particulate emissions could be reduced by 20%. Element analysis of the particulate emissions as well as particle size measurements showed that primarily large particles were separated. A retrot of the Hydrocube R by an ionizing electrode increased the degree of separation on 60%. Besides the separation of particles, the Hydrocube R also reduced gaseous emissions like SO2 and HCl. The absorption of these components in the condensate phase caused a decrease of the pH value. Low ph value increased the corrosion of the Hydrocube R , what could be detected by rising concentrations on Fe, Ni and Cr in the condensate.


Other Presentations | 2009

Untersuchung der Fördercharakteristik von Schneckenförderern für eine Pelletabwurffeuerung

Ohnmacht, R. Untersuchung der Fördercharakteristik von Schneckenförderern für eine Pelletabwurffeuerung, Master Thesis, Technologische Universität Wien, Vienna, Austria, 2009.

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Conference contributions | 2009

Unearthing waste`s potential for 100% renewable energy systems

Ragossnig A. Unearthing waste`s potential for 100% renewable energy systems. 5th SDEWES-conference 2009, 29th of September-3rd of October, Dubrovnik, Croatia.

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This paper focusses on the elaboration of the potential of the waste sector to contribute to the provision of 100% renewable energy systems. Waste is an abundant and locally available ressource and in many cases it is (at least partially) of biogenic origin, therefore pursuing political goals in waste management by energetic utilization of waste contributes towards achieving political goals in the energy as well as climate policy, too. However, it is shown based on the example of Austria that looking at energy systems on a national or international scale the waste sector is only able to contribute very little to the provision of the overall energy needed. It is different if one looks at specific energy systems in industrial sectors or on individual industrial sites. Here one must aknowledge that the energetic utilization of waste can have a high impact towards establishing renewable energy systems. Exemplarily this is shown by discussing the Austrian pulp & paper as well as the cement industry sector.


Peer Reviewed Scientific Journals | 2016

Two-stage cultivation of N-rich and N–deprived Acutodesmus obliquus biomass: Influence of cultivation and dewatering methods on microalgal biomass used in anaerobic digestion

Gruber M, Nussbaumer M, Jerney J, Ludwig I, Zohar E, Lang I, Bochmann G, Schagerl M, Obbard JP, Fuchs W, Drosg B. Two-stage cultivation of N-rich and N–deprived Acutodesmus obliquus biomass: Influence of cultivation and dewatering methods on microalgal biomass used in anaerobic digestion. Algal Research. July 2016;17: 105-112.

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Other Presentations | 2013

Two-Stage Anaerobic Digestion of Sugar Beet Pressed Pulp - Optimizing of reactor performance

Stoyanova E et al. Two-Stage Anaerobic Digestion of Sugar Beet Pressed Pulp - Optimizing of reactor performance, 13th World Congress on Anaerobic Digestion 2013, 25th-28th of June 2013, Santiago de Compostela, Spain. (peer reviewed) (visual presentation)

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Conference contributions | 2011

Trennung heterogener Abfälle durch sensorgestützte Sortierung zur Optimierung materialspezifischer Abfallbehandlung

Pieber S, Ragossnig A, Sommer M, Meirhofer M, Curtis A, Pomberger R. Trennung heterogener Abfälle durch sensorgestützte Sortierung zur Optimierung materialspezifischer Abfallbehandlung, Waste-to-Resources 2011, 24th-27th of May 2011, Hannover, Germany.

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Conference contributions | 2010

Trends and opportunities of micro-CHP technologies based on biomass combustion

Obernberger I. Trends and opportunities of micro-CHP technologies based on biomass combustion, 18th European Biomass Conference and Exhibition 2010, 3rd-7th of May 2010, Lyon, France. p 1-9.

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