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Conference contributions | 2013

Kerosin from wood over FT synthesis

Rauch R. Kerosin from wood over FT synthesis, 7. Kolloquium Sustainable BioEconomy, KIT, 9th of December 2013, Karlsruhe, Germany. (oral presentation)

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Conference Papers | 2013

Leak air in a double-wall chimney system

Lichtenegger K, Hebenstreit B, Pointner C. Leak air in a double-wall chimney system. Journal of Physics: Conference Series. 2013;410:012059. (peer reviewed)

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Operating biomass stoves in modern buildings with tight shells often requires a room-independent air supply. One possibility to arrange this supply is to use a double-wall chimney with fresh air entering through the annular gap. For this setup, a mathematical model has been developed and checked with experimental data. It turned out that for commercially available chimneys, leakage is not negligible and inclusion of leak air in the calculation is crucial for reproduction of the experimental data. Even with inclusion of this effect, discrepancies remain which call for further investigations and a refinement of the model.


Contributions to trade journals | 2013

Life cycle modeling of energy matrix scenarios, Belgian power and partial heat mixes as case study

Rubio Rodríguez MA, Feitó Cespón M, De Ruyck J, Ocaña Guevara VS, Verma VK. Life cycle modeling of energy matrix scenarios, Belgian power and partial heat mixes as case study. Appl Energy. 2013;107:329-37.

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The present paper introduces a life cycle modeling approach for representing actual demand of energy or energy intensive products delivered within a system (electricity, heat, etc.) for optimization of the energy mix, according to some of the available life cycle impact assessments (LCIAs). Unlike classical LCA modeling approach, the real amount of several energy products leaving the system and the interactions due to the presence of multi-output processes are considered within the present approach. As a case study, future scenarios are obtained for the Belgian electricity mix production and the heat mix potentially substituted by CHP or biomass, switching between abandoning or not power from nuclear energy. The possibility of using natural gas, biomass for cogeneration, wind power and solar photovoltaic energy are considered within the availability ranges of these resources. Finally, results are presented from successive optimizations according to the sustainability potential defined in a previous paper. A pathway to a more sustainable Belgian energy system is obtained. Finally it is concluded that under the modeling conditions and without nuclear energy it is not possible to obtain a reduction of GHGs and despite diminishing of non-renewable resource consumption, a rising of toxicity is obtained. © 2013 Elsevier Ltd.


Conference contributions | 2013

Logwood Stove with Automatic Air Control Powered by Thermoelectric Generators

Mair C, Höftberger E, Moser W. Logwood Stove with Automatic Air Control Powered by Thermoelectric Generators, Word Sustainable Energy Days next 2013, 27th-28th of February 2013, Wels, Austria.

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Contributions to trade journals | 2013

Mathematical modeling of sulfur deactivation effects on steam reforming of producer gas produced by biomass gasification

Sadooghi P, Rauch R. Mathematical modeling of sulfur deactivation effects on steam reforming of producer gas produced by biomass gasification. Fuel Process Technol. 2013;110:46-52.

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Product gas produced by biomass gasification contains small amounts of sulfur compounds (hydrogen sulfide) which can reduce catalyst activity during steam reforming process. Sulfur removal has a negative effect on process efficiency and steam reforming has to be run without cleaning the gas prior to the reactor. It is therefore of interest to investigate the effect of sulfur on the performance of steam reforming reactions. In this work a packed bed reactor filled with nickel based catalysts is mathematically modeled to simulate the steady state pseudo-heterogeneous equations representing heat and mass transfer in the reactor tube. Catalytic bed is subjected to hydrogen sulfide and an isotherm model for the sulfur coverage on the Ni surface is considered to exactly investigate sulfur poisoning effects on methane conversion, hydrogen yield, carbon dioxide and carbon monoxide concentration. It is shown that even when present in the hydrocarbon feedstock in small quantities, (ppm) levels, sulfur can have a significant effect in methane conversion and temperature distribution within the reactor. © 2013 Elsevier B.V.


Contributions at other events | 2013

Metodologie per il campionamento di particolato prodotto da apparecchi per la combustione di biomassa solida

Andrea, Pizzi. Metodologie per il campionamento di particolato prodotto da apparecchi per la combustione di biomassa solida, Ph.D. Thesis, Marche Polytechnic University, Ancona, Italy, 2013.

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La combustione di biomassa legnosa con piccoli apparecchi e caldaie è oggi vista con rinnovato interesse per il raggiungimento degli obiettivi comunitari di produzione di energia rinnovabile al 2020. L’aumento dell’utilizzo della biomassa combustibile è di stretto interesse del settore agroforestale, per via del notevole indotto economico che peraltro interessa tutto il territorio nazionale. Tuttavia, la combustione della biomassa è legata ad una serie di problematiche ambientali quali le emissioni in atmosfera di polveri sottili che influenzano direttamente la qualità dell’aria. Si ritiene, quindi, che l’auspicato aumento dell’utilizzo delle biomasse, soprattutto ai fini della produzione di calore (riscaldamento ambienti), sia legata al contenimento delle emissioni al camino. In questo contesto, è quindi importante la corretta misura delle polveri emesse dagli apparecchi di riscaldamento domestico alimentati a biomassa solida, tenendo conto anche della frazione condensabile, come richiesto dalla normativa. Il lavoro mette a confronto due tecniche di misura delle polveri, la tecnica di prelievo a caldo con raffreddamento dei fumi in impinger e la tecnica di diluizione con tunnel. Sono stati selezionati per il confronto due apparecchi di ridotta potenza (< 15 kWt) ed elevata efficienza: una caldaia a pellet ed una stufa a pellet. In condizioni di combustione completa le due tecniche restituiscono fattori di emissione simili. Nella stufa a pellet la misura a freddo è maggiore del 20 – 30 % rispetto alla misura a caldo. La ridotta presenza della frazione condensabile è stata confermata dall’analisi NPOC degli impinger. Sono state misurate le emissioni totali prodotte da un utilizzo reale del dispositivo, comprendendo anche le fasi transitorie di combustione (accensione, riscaldamento a regime e spegnimento), solitamente non considerate nelle misure standard di laboratorio. La fase di accensione produce fino a tre volte le polveri emesse in condizioni stazionarie. L’emissione totale si riduce all’aumentare del tempo di utilizzo del dispositivo, rientrando nell’intervallo delle emissioni delle condizioni stazionarie dopo circa 6 h. Gli IPA, emessi in quantità elevate, sono costituiti maggiormente da congeneri a peso molecolare medio – basso, associati a minore tossicità. Il TEQ è funzione della potenza e delle condizioni di
combustione del dispositivo.


Conference contributions | 2013

Micro and small scale pellets CHPs. Technology survey.

Haslinger W, Aigenbauer S, Höftberger E. Micro and small scale pellets CHPs. Technology survey, European Pellets Conference 2013, 27th-28th of February 2013, Wels, Austria.

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Other Presentations | 2013

Microbial conversion of H2S for sulphuric acid recycling

Rachbauer L, Gabauer W, Ortner M, Bochmann G. Microbial conversion of H2S for sulphuric acid recycling, 9th International Conference on Renewable Resources & Biorefineries 2013, 5th-7th of June 2013, Antwerpen, Belgium. (peer reviewed) (visual presentation)

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Conference contributions | 2013

Modellbildung von Luft- und Rauchgasrezirkulations-Zufuhren bei Biomasse-Feuerungsanlagen

Schörghuber C, Gölles M, Dourdoumas N, Brunner T, Obernberger I. Modellbildung von Luft- und Rauchgasrezirkulations-Zufuhren bei Biomasse-Feuerungsanlagen, 18. Steirisches Seminar über Regelungstechnik und Prozessautomatisierung 2013, 2nd-5th of September 2013, Leibnitz, Austria.

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Other Presentations | 2013

Modellierung und Regelung von Biomasse-Thermoölkesselanlagen

Dietachmayr, F. Modellierung und Regelung von Biomasse-Thermoölkesselanlagen, Master Thesis, Master Thesis, Technische Universität Graz, Graz, Austria, 2013.

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Die Verbrennung fester Biomasse gewinnt als nachhaltige Form der Energieerzeugung stetig an Bedeutung. Eine mögliche Technologie stellen dabei Biomasse-Thermoölkesselanlagen dar, deren Regelungen bis jetzt noch nicht auf einem mathematischen Modell basieren und dementsprechend deren verkoppeltes und zum Teil nichtlineares Verhalten nur ungenügend berücksichtigen. Ziel dieser Arbeit ist es, ein für Biomassefeuerungsanlagen mit Wasserkesseln existierendes Modell sowie die darauf aufbauende Regelungsstrategie an die speziellen Gegebenheiten von Thermoölkesselanlagen anzupassen. Dazu wird zunächst ein einfaches Modell für Thermoölwärmeübertrager auf Basis einer Energiebilanz hergeleitet und anhand von verfügbaren Betriebsdaten qualitativ verifiziert. Anschließend wird die bei der Regelung von Wasserkesselanlagen eingesetzte Eingangs-Ausgangslinearisierung verallgemeinert. Darauf aufbauend wird eine Regelungsstrategie zur Regelung des Thermoölwärmeübertragers hergeleitet. Die Leistungsfähigkeit des Regelungskonzeptes wird schließlich in Simulationsstudien gezeigt. 


Contributions at other events | 2013

Modelling of biomass packed bed combustion

Mehrabian, R. Modelling of biomass packed bed combustion, Ph.D. Thesis, Graz University of Technology, Graz, Austria, 2013.

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 Im Bereich der thermischen Biomassenutzung (speziell Rostfeuerungen) werden CFD-Simulationen eingesetzt, um Hilfestellung bei der Diagnose und Lösung von Betriebsproblemen zu leisten sowie bei der Entwicklung von neuen Feuerungen und Kesseln zu unterstützen. Zurzeit sind keine Modelle verfügbar, mit denen sowohl die Vorgänge im Brennstoffbett als auch in der Gasphase einer Biomasse-Rostfeuerung mit Hilfe von detaillierten numerischen Modellen bei akzeptabler Berechungszeit simuliert werden können. Um die direkte Kopplung des Bett-Modells mit der Gasphase zu bewerkstelligen, ist es nötig, ein geeignetes Partikel-Modell zu entwickeln, welches die thermische Konversion (Trocknung, Pyrolyse und Holzkohle-Ausbrand) von thermisch dicken Biomassepartikeln beschreibt und mit bereits vorhandenen CFD-Modellen für die Gasphasensimulation gekoppelt werden kann. In diesem Schalenmodell werden die einzelnen Biomassepartikel als thermisch dick behandelt, d.h. die Temperaturgradienten in den einzelnen Partikeln sowie der gleichzeitige Ablauf mehrerer Umwandlungsprozesse berücksichtigt. Das Schalenmodell wurde mit Hilfe von gemessenen Partikeloberflächen- und -zentrumstemperaturen sowie mit Messwerten des Gesamtmasseverlustes während der Verbrennung in einem Einzel-Partikelreaktor validiert. Ein weiteres Problem, das bei der Simulation von Biomasse-Rostfeuerungen auftritt, ist die Modellierung der Gas-Festkörper-Mehrphasenströmung. Das Modell muss dabei in der Lage sein, den Einfluss der Partikel-Partikel-Wechselwirkung währenden der Partikelbewegung am Rost korrekt zu beschreiben. Aus diesem Grund wurde durch Kopplung von Euler- und Lagrange Mehrphasenströmungs- Ansätzen ein neues, dreidimensionales Schüttungsmodell entwickelt. Dabei wird die Partikelbewegung am Rost mit Hilfe eines Euler-Ansatzes (Euler-Granular-Modell) beschrieben, während die thermische Umwandlung der Biomassepartikel mit Hilfe eines Lagrange-Ansatzes und dem entwickelten Einzelpartikelmodell beschrieben wird. Das 3D-Festbettmodell für Biomasserostfeuerungen wurde eingesetzt, um eine 20 kW Biomasse-Unterschubfeuerung zu simulieren. Da es keine experimentelle Daten hinsichtlich der Bedingungen im Brennstoffbett gab, wurden qualitative Informationen hinsichtlich der Positionen der Trocknungs-, Pyrolyse- und Holzkohle-Ausbrandzonen, sowie mit Thermoelementen gemessenen Rauchgastemperaturen an verschiedenen Positionen in der Brennkammer zum Vergleich mit den Simulationsergebnissen herangezogen. Des Weiteren erfolgte im Zuge dieser Arbeit eine Weiterentwicklung des Festbett-Modells, indem der Strahlungsaustausch zwischen den Partikeln sowie detaillierte kinetische Modelle für die Gasphasenverbrennung im Modell implementiert wurden. Das weiterentwickelte Modell wurde mit Hilfe von experimentellen Daten aus Testläufen in einem Festbett-Laborreaktor validiert. Diese Messdaten beinhalten gemessene Konzentrationen von CO, CO2, CH4, H2, H2O und O2 im Rauchgas über dem Brennstoffbett sowie Temperaturen in unterschiedlichen Positionen im Bett und über dem Bett. Die vorhergesagten Werte zeigten eine gute Übereinstimmung mit den gemessenen Werten.


Conference contributions | 2013

New concepts for converting renewable electricity to transportation fuels by CO2 gasification

Rauch R. New concepts for converting renewable electricity to transportation fuels by CO2 gasification, 1st International Industrial Seminar Messer Benelux 2013, 18th of April 2013, Antwerp, Belgium.

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Other Presentations | 2013

Online-Monitoring von Korrosionsvorgängen in Biomasse-befeuertenAnlagen

Bernsteiner, C. Online-Monitoring von Korrosionsvorgängen in Biomasse-befeuertenAnlagen, Master Thesis, Technische Universität Graz, Graz, Austria, 2013.

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Für den ökonomisch und ökologisch effizienteren Betrieb von Dampfkesselanlagen ist die Untersuchung von Korrosionsvorgängen in Wärmetauschern, verursacht durch das Rauchgas aus einer Biomasse-Feuerung, notwendig. Daher wurden bei Bioenergy 2020+ kurzzeitige Korrosionsversuche im Umfang von 300h Betriebszeit an einem Wärmetauscherstahl 13CrMo4-5 mit einer ONLINE-Korrosionssonde der Firma Corrmoran GmbH für die Erstellung eines empirischen Korrosionsmodells durchgeführt. Als Brennstoffe dienten Waldhackgut, Weizenstrohpellets und Altholz. Die Messung benötigt eine Ionen leitende Deckschicht, die sich erst am Beginn des Versuchs aufbaut. Aufgrund der fehlenden Deckschicht wird daher zu Beginn der Messung der Korrosionsleitwert unterschätzt. Daraus ergeben sich systematische Messfehler. Ziel dieser Arbeit war die Eruierung des Zusammenhanges zwischen Messfehler und Versuchszeit. Dabei stellten sich zwei systematische Messfehler als relevant heraus: •Die Abzehrrate ist zum Korrosionsleitwert proportional. Daher wird die Abzehrrate während der Eingangsphase der Messung unterschätzt. •Die Abzehrrate berechnet sich aus dem Korrosionsleitwert, multipliziert mit einem Kalibrierungsfaktor. Dabei ergibt sich der Kalibrierungsfaktor aus dem Verhältnis des gesamten korrosionsbedingten Materialverlustes über die gesamte Versuchsdauer, dividiert durch den über denselben Zeitraum integrierten Korrosionsleitwert. Aufgrund des zu Beginn unterschätzten Korrosionsleitwertes wird der Kalibrierungsfaktor und somit die Abzehrrate, berechnet aus dem reproduzierbaren Signal, überschätzt. Die Literaturrecherche zeigte, dass die Kinetik bei der Hochtemperaturkorrosion bei konstant gehaltenen korrosionsrelevanten Parametern einen linearen, parabolischen oder paralinearen Verlauf einnehmen kann. Die kleinstmögliche Abzehrrate und somit der kleinstmögliche Korrosionsleitwert zu Beginn der Messung ergibt sich bei der Annahme eines linearen Verlaufs, welcher die möglicherweise erhöhten Abzehrraten der Initialkorrosion nicht mitberücksichtigt. Aus dieser Annahme konnte der kleinstmögliche Korrekturfaktor cmin berechnet werden. Dazu mussten die Daten bei konstant gehaltenen Parametern gefiltert und daraus der zeitlich integrierte Korrosionsleitwert PL,Messung gebildet werden. Das Verhältnis von PL,Messung mit einem über die gesamte Versuchszeit konstant angenommenen zeitlich integrierten Korrosionsleitwertes PL,linear ergibt den Korrekturfaktor, der multipliziert mit den ursprünglich bei gleichen Parametern bestimmten Abzehrraten eine neue Abzehrrate k(t)neu ergibt. Der Vergleich mit den Ergebnissen eines Langzeitversuches unter ähnlichen Betriebsbedingungen in einem Biomasse-Heizkraftwerk zeigte dadurch eine Verbesserung der Abweichung der Kurzzeitversuche von 125% auf 55%. Aufgrund der Parametervariationen sowie der Temperaturschwankungen, verursacht durch Ein- und Ausschaltvorgänge der Anlage, haben die bei konstanten Parametern bestimmten Korrekturfaktoren für die durchgeführten Versuche nur bedingt Gültigkeit. Daher wurde in einem weiteren Schritt ein Korrekturfaktor cmin,var bestimmt, welcher alle Daten der Versuchsserie berücksichtigt. Dazu wurde das Signal der Eingangsphase durch ein gleichlanges reproduzierbares Signal, gemessen unter denselben Bedingungen am Ende der Versuchsserien, ersetzt. Es ergibt sich aus dem Verhältnis der zeitlich integrierten Korrosionsleitwerte PL,Messung der Originalkurve zu PL,idealisiert des idealisierten Verlaufs der Korrekturfaktor cmin,var. Dieser hat aufgrund der Berücksichtigung aller gesammelten Daten für alle bei den Versuchen bestimmten Abzehrraten Gültigkeit. Durch cmin,var konnte eine Reduktion der Abweichung auf 110% erreicht werden. Diese wird auf die im Gegensatz zur Langzeitmessung im Biomasse-Heizkraftwerk unterschiedliche Versuchsmethode sowie auf den unbekannten Einfluss der möglicherweise erhöhten Abzehrraten der Initialkorrosion zurückgeführt.  


Conference contributions | 2013

Operation characteristics of a bulk catalyst in a test stand under similar conditions to a firewood stove

Wöhler M, et al. Operation characteristics of a bulk catalyst in a test stand under similar conditions to a firewood stove, Word Sustainable Energy Days next 2013, 27th-28th of February 2013, Wels, Austria.

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Other Presentations | 2013

Optimierung des Emissionsverhaltens eines Ofens mittels primären und sekundären Maßnahmen am Beispiel des Scheitholzofens

Rieger, B. Optimierung des Emissionsverhaltens eines Ofens mittels primären und sekundären Maßnahmen am Beispiel des Scheitholzofens, Master Thesis, Fachochschule Technikum Wien, Vienna, Austria, 2013.

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The use of biomass in manually charged room heating appliances to cover the domestic heating demand has traditionally been of a high percentage in the European Union. As a result of continued or even increased use of firewood stoves, the enhancement of available stoves is a declared objective of the European Union.
Therefore, an example-optimization of the firewood stove Stûv 16/78-in (available on the European market) was performed in preparation of this paper. There was a primary- and a secondary optimization carried out to quantify the potential of optimization. When optimizing, the gas and particulate emissions was considered. The operating behavior were measured and evaluated by performing combustion experiments on a specially designed test rig.
The primary optimization is divided into five sub-steps. Each Step was quantified by gas analysis. The achieved reduction of particulate emissions was measured before and after the entire primary optimization.
In comparison to the delivery condition it was possible to reduce the CO emissions to one quarter and the particulate emissions from 100 mg / mn³ to 39 mg / mn³ over the course of the primary optimization.
As a secondary optimization, a Catalyst was implemented. The used catalyst is a solid-state catalyst in the modification of a heterogeneous supported catalyst in the shape of honeycomb, which is marketed by Clariant International Ltd. under the name "EnviCat ® Longlife Plus". The catalytically active materials platinum and palladium are used.
After a strictly implemented primary optimizations, a further reduction to half of emissions was achieved by the integration of the catalyst even though a bypass of 20 % had to be integrated to ensure the operating safety.


Peer-reviewed publications | 2013

Overview of Forestry and Wood Fuel Supply Chains in Austria; Investment Costs and Profitability of Biomass Heating Plants in Austria; Business Models from Austria Covering the Entire Wood Heat Supply Chain

Otepka P, Kristöfel C, Strasser C, et al. Guidebook on Local Bioenergy Supply Based on Woody Biomass. Overview of Forestry and Wood Fuel Supply Chains in Austria; Investment Costs and Profitability of Biomass Heating Plants in Austria; Business Models from Austria Covering the Entire Wood Heat Supply Chain. ISBN 978-1-938681-98-1. 2013:2-36;57-112.

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Contributions to trade journals | 2013

Performance improvement of dual fluidized bed gasifiers by temperature reduction: The behavior of tar species in the product gas

Kirnbauer F, Wilk V, Hofbauer H. Performance improvement of dual fluidized bed gasifiers by temperature reduction: The behavior of tar species in the product gas. Fuel. 2013;108:534-42.

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To meet the aims of the worldwide effort to reduce greenhouse gas emissions, product gas from biomass steam gasification in DFB (dual fluidized bed) gasification plants can play an important role for the production of electricity, fuel for transportation and chemicals. Using a catalytically active bed material, such as olivine, brings advantages concerning tar reduction in the product gas. Experience from industrial scale gasification plants showed that a modification of the olivine occurs during operation due to the interaction of the bed material with ash components from the biomass and additives. This interaction leads to a calcium-rich layer on the bed material particles which influences the gasification properties and reduces tar concentration in the product gas. In this paper, the influence on the gasification performance, product gas composition and tar formation of a reduction of the gasification temperature are studied. A variation of the gasification temperature from 870 °C to 750 °C was carried out in a 100 kW pilot plant. A reduction of the gasification temperature down to 750 °C reduces the concentration of hydrogen and carbon monoxide in the product gas and increases the concentration of carbon dioxide and methane. The product gas volume produced per kg of fuel is reduced at lower gasification temperatures but the calorific value of the product gas increases. The volumetric concentration of tars in the product gas increases slightly until 800 °C and nearly doubles when decreasing the gasification temperature to 750 °C. The tars detected by gas chromatography-mass spectrometry (GCMS) were classified into substance groups and related to the fuel input to the gasifier and showed a decrease in naphthalenes and polycyclic aromatic hydrocarbons (PAHs) and an increase in phenols, aromatic compounds and furans when reducing the gasification temperature. The comparison with results from an earlier study, where the gasification properties of unused fresh olivine were compared with used olivine, underlines the importance of a long retention time of the bed material in the gasifier, ensuring the formation of a calcium-rich layer in the bed material. © 2012 Elsevier Ltd. All rights reserved.


Contributions to trade journals | 2013

Performance of a pellet boiler fired with agricultural fuels

Carvalho L, Wopienka E, Pointner C, Lundgren J, Verma VK, Haslinger W, et al. Performance of a pellet boiler fired with agricultural fuels. Appl Energy. 2013;104:286-96.

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The increasing demand for woody biomass increases the price of this limited resource, motivating the growing interest in using woody materials of lower quality as well as non-woody biomass fuels for heat production in Europe. The challenges in using non-woody biomass as fuels are related to the variability of the chemical composition and in certain fuel properties that may induce problems during combustion. The objective of this work has been to evaluate the technical and environmental performance of a 15. kW pellet boiler when operated with different pelletized biomass fuels, namely straw (Triticum aestivum), Miscanthus (Miscanthus× giganteus), maize (Zea mays), wheat bran, vineyard pruning (from Vitis vinifera), hay, Sorghum (Sorghum bicolor) and wood (from Picea abies) with 5% rye flour. The gaseous and dust emissions as well as the boiler efficiency were investigated and compared with the legal requirements defined in the FprEN 303-5 (final draft of the European standard 303-5). It was found that the boiler control should be improved to better adapt the combustion conditions to the different properties of the agricultural fuels. Additionally, there is a need for a frequent cleaning of the heat exchangers in boilers operated with agricultural fuels to avoid efficiency drops after short term operation. All the agricultural fuels satisfied the legal requirements defined in the FprEN 303-5, with the exception of dust emissions during combustion of straw and Sorghum. Miscanthus and vineyard pruning were the best fuels tested showing comparable emission values to wood combustion. © 2012 Elsevier Ltd.


Conference contributions | 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)

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Contributions to trade journals | 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.

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A 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.


Contributions to trade journals | 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.

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Current 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 Presentations | 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.

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Conference contributions | 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.

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Most 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.


Conference contributions | 2013

Steam gasification of challenging fuels in the dual fluidized bed gasifier

Wilk V, Hofbauer H. Steam gasification of challenging fuels in the dual fluidized bed gasifier, 21st European Biomass Conference and Exhibition 2013, 3rd-7th of June 2013, Copenhagen, Denmark.

Details

In order to enlarge the range of feedstock for the dual fluidized bed (DFB) gasification process, the influence of several fuel properties was studied in the 100 kW DFB pilot plant. Fuels with high concentration of nitrogen and sulfur, fuels with an increased concentration of fine particles, and fuels with extremely high content of volatiles were tested. The DFB gasification system is found to be robust and can handle all the materials. Nitrogen, sulfur and chlorine from the fuel are predominantly converted in the gasification reactor, either to gases (nitrogen, sulfur) or bound to ash (chlorine, sulfur). For the performance of the DFB gasifier, sufficient contact of fuel, product gas and bed material is important. Increasing amounts of fine particles or volatiles in the fuels lead to higher tar loads in the product gas, because the residence time of fuel particles in bubbling fluidized bed is shorter.


Books / Bookchapters | 2013

Storage and pre-treatment of substrates for biogas production

Bochmann G, Montgomery L. Storage and pre-treatment of substrates for biogas production. The biogas handbook. ISBN 978 0 85709 498 8 2013:85-103.

External Link

Details

Biogas substrates are typically moist, which can make them difficult to store because bacteria and mould can grow on them. Ensiling, which involves the production of acid by lactic acid bacteria, is often used to preserve crops cheaply. Biogas substrates are also often fibrous, which can make them difficult to mix and means that some of their energy is locked up within the fibres. Different pre-treatment technologies are being investigated to access the energy in these fibres, to increase the rate of biogas production and to improve the mixing qualities of the substrates. Pre-treatment technologies are based on three principles: physical (including mechanical shear, heat, pressure and electric fields), chemical (acids, bases and solvents) and biological (microbial and enzymatic). Combinations of these principles are also used, including steam explosion, extrusion and thermo-chemical processes. Although many of these processes have been investigated at small scale, few have been analysed at large scale in un-biased studies. Many of these techniques are associated with high energy input (e.g. mechanical and heat pre-treatment), high equipment costs (e.g. mechanical systems where the blades erode) or use large volumes of chemicals (e.g. alkali pre-treatment). Different pre-treatment technologies work better with different substrates, and more research is required in this field to understand which combinations are worthwhile. This chapter describes some of the common pre-treatment technologies along with some advantages and disadvantages.


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