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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.

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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.

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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.


Conference contributions | 2013

Suitable gasification methods and gas cleaning schemes for BtL application of producer gas

Rauch, R. New processes for fuel conversion, gas cleaning and CO2 separation in FB and EF gasification of coal, biomass and waste, Workshop ” Suitable gasification methods and gas cleaning schemes for BtL application of producer gas” (held during the First International Workshop on New processes for fuel conversion, gas cleaning and CO2 separation in FB and EF gasification of coal, biomass and waste) 12th-14th of June, Prague, Czech, 2013.

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Conference contributions | 2013

Synthetic biofuels – do they have a future?

Rauch R. Synthetic biofuels – do they have a future? 8th A3PS Conference Eco-Mobility 2013, 4th of October 2013, Vienna, Austria.

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Contributions to trade journals | 2013

The mechanism of bed material coating in dual fluidized bed biomass steam gasification plants and its impact on plant optimization

Kirnbauer F, Hofbauer H. The mechanism of bed material coating in dual fluidized bed biomass steam gasification plants and its impact on plant optimization. Powder Technol. 2013;245:94-104.

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The bed material and especially its catalytic activity plays an important role in biomass steam gasification in dual fluidized bed gasifiers. The bed material is modified by interaction with biomass ash during operation of the gasification plant forming layers at the particles which are induced by the biomass ash. Optimization of dual fluidized biomass steam gasification will have significant influence on the process variables such as temperatures, inorganic composition and product gas composition. The influence of these changes on layer formation is still unknown. This paper summarizes results of investigations about bed material characteristics taken from the industrial-scale biomass steam gasification plant in Güssing where woody biomass is used as fuel. Analyses of the surface and the crystal structures of the bed material particles treated in gasification and combustion atmospheres were carried out. The thermal behavior of used olivine and fresh olivine in different atmospheres was analyzed. A suggestion for the mechanism of formation of the layers is presented and the influence of possible optimization measures is discussed. A change in the elemental composition of the surface was not detectable but a slight change in the crystal structure. Thermal investigations show a weak endothermic weight loss with used olivine in a CO2-rich atmosphere which could not be determined with fresh olivine. The formation of layers at the olivine particles is considered to be caused by the intensive contact with burning char particles in the combustion reactor. © 2013 Elsevier B.V.


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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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 | 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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Conference contributions | 2012

2nd Generation Biofuels from Biomass by steam gasification

Rauch R. 2nd Generation Biofuels from Biomass by steam gasification, 1. Nürnberger Fach-Kolloquium Methanisierung und Second Generation Fuels 2012, 29th-30th of May 2012, Nürnberg, Germany.

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Reviewed Conference Papers | 2012

A CFD model for thermal conversion of thermally thick biomass particles

Mehrabian R, Zahirovic S, Scharler R, Obernberger I, Kleditzsch S, Wirtz S, et al. A CFD model for thermal conversion of thermally thick biomass particles. Fuel Process Technol. 2012;95:96-108.

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A one-dimensional model for the thermal conversion of thermally thick biomass particles is developed for the simulation of the fuel bed of biomass grate furnaces. The model can be applied for cylindrical and spherical particles. The particle is divided into four layers corresponding to the main stages of biomass thermal conversion. The energy and mass conservation equations are solved for each layer. The reactions are assigned to the boundaries. The model can predict the intra-particle temperature gradient, the particle mass loss rate as well as the time-dependent variations of particle size and density, as the most essential features of particle thermal conversion. When simulating the fuel bed of a biomass grate furnace, the particle model has to be numerically efficient. By reducing the number of variables and considering the lowest possible number of grid points inside the particle, a reasonable calculation time of less than 1 min for each particle is achieved. Comparisons between the results predicted by the model and by the measurements have been performed for different particle sizes, shapes and moisture contents during the pyrolysis and combustion in a single-particle reactor. The results of the model are in good agreement with experimental data which implies that the simplifications do not impair the model accuracy.


Other Presentations | 2012

Abbilden des instationären Betriebs eines Pelletkessel durch Messung und Simulation

Schnetzinger, R. Abbilden des instationären Betriebs eines Pelletkessel durch Messung und Simulation, Diploma Thesis, FH Oberösterreich, Wels, Austria, 2012.

Details

This thesis focuses on portraying the thermal behavior of a biomass pellet boiler through measurement and simulation. During operation the power of a pellet boiler changes depending on the heat demand. Detailed measurements were conducted to record this changing behavior of some boilers and estimate their levels of efficiencies. Subsequently a mathematical model was created to emulate boilers and their thermal performance without such measurements. The first part of this thesis deals with the description of the simulation model and the measurements which were carried out. Secondly, the verification of the model is discussed. For this verification simulation results of three different boilers are compared to measurement data and pictured in various diagrams. The last part of this thesis is about further simulations of these three boilers where the control units were emulated too. The model was built in the MATLAB/Simulink® environment and is generally based on
thermodynamic relationships and heat balances in a boiler. However, through constant comparison of the simulation results with the measurement data some parameters were adapted to fit the simulation to reality. Therefore this model is “semi-empirical” as physical correlations are included but some parameters were deduced from measurement. Following, the verification of the model is discussed through the comparison of measurement data and simulation results. For the verifications the boiler power, fuel mass flow as well as
the heat consumption were taken from the measurement data and set as input for the simulation. The calculated results show that the boiler model enables to portray the thermal behavior of the three boilers tested with only small divergences. At the end of this thesis it was attempted to model the control unit of the three boilers by analyzing the measurement data. Having a model for the control unit, the inputs from the measurement data are reduced to just two variables, the water inlet temperature and the water volume flow (heat consumption). The comparison of the calculated values to the measurement data shows slightly higher divergences than during the validation, especially where the simulated control unit does not behave like the real one. Through the simulation of further boilers the model could be continuously enhanced. In the future this “virtual boiler” should be used to test control algorithms of boiler control units to enhance their efficiencies.


Contributions to trade journals | 2012

Acute systemic and lung inflammation in C57Bl/6J mice after intratracheal aspiration of particulate matter from small-scale biomass combustion appliances based on old and modern technologies

Uski OJ, Happo MS, Jalava PI, Brunner T, Kelz J, Obernberger I, Jokiniemi J, Hirvonen M-R. Acute systemic and lung inflammation in C57Bl/6J mice after intratracheal aspiration of particulate matter from small-scale biomass combustion appliances based on old and modern technologies. Inhalation Toxicology. 2012;24(14):952-965.

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Conference contributions | 2012

Advanced biomass fuel characterisation based on tests with a specially designed lab-scale reactor

Brunner T, Biedermann F, Kanzian W, Evic N, Obernberger I. Advanced biomass fuel characterisation based on tests with a specially designed lab-scale reactor, Conference Impacts of Fuel Quality on Power Production and Environment 2012, 23th-27th of September 2012, Puchberg, Austria.

Details

To examine relevant combustion characteristics of biomass fuels in grate combustion systems, a specially designed lab-scale reactor was developed. On the basis of tests performed with this reactor, information regarding the biomass decomposition behavior, the release of NOx precursor species, the release of ash-forming elements, and first indications concerning ash melting can be evaluated. Within the scope of several projects, the lab-scale reactor system as well as the subsequent evaluation routines have been optimized and tests with a considerable number of different biomass fuels have been performed. These tests comprised a wide variation of different fuels, including conventional wood fuels (beech, spruce, and softwood pellets), bark, wood from short rotation coppice (SRC) (poplar and willow), waste wood, torrefied softwood, agricultural biomass (straw, Miscanthus, maize cobs, and grass pellets), and peat and sewage sludge. The results from the lab-scale reactor tests show that the thermal decomposition behavior and the combustion behavior of different biomass fuels vary considerably. With regard to NOx precursors (NH3, HCN, NO, N2O, and NO2), NH3 and, for chemically untreated wood fuels, also HCN represent the dominant nitrogen species. The conversion rate from N in the fuel to N in NOx precursors varies between 20 and 95% depending upon the fuel and generally decreases with an increasing N content of the fuel. These results gained from the lab-scale reactor tests can be used to derive NOx precursor release models for subsequent computational fluid dynamics (CFD) NOx post-processing. The release of ash-forming vapors also considerably depends upon the fuel used. In general, more than 91% of Cl, more than 71% of S, 1–51% of K, and 1–50% of Na are released to the gas phase. From these data, the potential for aerosol emissions can be estimated, which varies between 18 mg/Nm3 (softwood pellets) and 320 mg/Nm3 (straw) (dry flue gas at 13% O2). Moreover, these results also provide first indications regarding the deposit formation risks associated with a certain biomass fuel. In addition, a good correlation between visually determined ash sintering tendencies and the sintering temperatures of the different fuels (according to ÖNORM CEN/TS 15370-1) could be observed.


Conference contributions | 2012

Advanced Motor Fuels

Bacovsky D. Advanced Motor Fuels, Eco-Mobility Conference 2012, 11th-12th of December 2012, Vienna, Austria.

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Other Presentations | 2012

Analyse ausgewählter europäischer Biomassemärkte

Hollinger, K. Analyse ausgewählter europäischer Biomassemärkte, Diploma Thesis, FH-Burgenland, Pinkafeld, Austria, 2012.

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Other Publications | 2012

Analytical approach for the determination of micro elements in anaerobic digestion systems by sequential extraction technique

Rachbauer, L. Analytical approach for the determination of micro elements in anaerobic digestion systems by sequential extraction technique, Master Thesis, University of Natural Resources and Life Sciences Vienna, Vienna, Austria, 2012.

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Der Einfluss von Nährstoffzusammensetzung und Additivzugabe beim anaeroben Abbau organischer Substanz stieß in den letzten Jahren vermehrt auf Interesse. Im Besonderen Spurenelemente haben erwiesenermaßen erheblichen Einfluss auf u.a. methanogene Archaeen und deren metabolische Aktivität. Massive Probleme der Prozessstabilität speziell bei Monovergärung unterschiedlichster Substrate können durch Co-Fermentation oder gezielte Zudosierung von Spurenelementmischungen überwunden werden. Ein profundes Verständnis der Wirkung dieser Elemente auf die verschiedenen mikrobiellen Spezies im Biogasreaktor als auch ihre Verfügbarkeit, ist die Voraussetzung für eine wirtschaftliche Gestaltung des anaeroben Fermentationsprozesses organischer Roh- als auch Reststoffe. Der heutige Stand-der-Technik zur Analyse von Biogasproben hat seinen Ursprung in der Wasser-, Abwasser- und Schlammanalytik und besteht aus einem einzelnen Filtrationsschritt vor Elementdetektion mittels ICP-OES bzw. ICP-MS. Diese Methodik erlaubt nur einen äußerst begrenzten Einblick in die Verteilung von essentiellen Spurenelementen in Anaerobreaktoren. Eine aussagekräftige Beurteilung der mikrobiellen Verfügbarkeit von beispielsweise Cobalt, Nickel oder Molybdän ist somit nur eingeschränkt möglich. Ziel dieser Arbeit war es, eine bestehende Methode zur sequentiellen Extraktion aus dem Bereich der Boden- und Sedimentanalytik für die Anwendung auf Biogasproben zu adaptieren. Der daraus resultierende Einblick in die Verteilung von Spurenelementen in den einzelnen Fraktionen erlaubt eine genauere Bewertung der mikrobiellen Verfügbarkeit von Nährstoffen in Biogasreaktoren, verglichen mit bestehenden analytischen Untersuchungsmethoden. Anforderungen an das Verfahren wie die Reproduzierbarkeit der Daten, zeitsparende Analytik und wirtschaftliche Realisierbarkeit konnten erfüllt werden. Wiederfindungsraten zwischen 90 und 110 % wurden für die wichtigsten Spurenelemente erreicht. Durch die sequentielle Extraktion konnte gezeigt werden, dass essenzielle Mikro-Nährstoffe bis zu 98 % in einer unlöslichen Form vorliegen können. Die Ergebnisse dieser Arbeit belegen die Anwendbarkeit der entwickelten Methodik zur Spurenelement-Extraktion in Anaerob-Systemen.


Conference contributions | 2012

Annual efficiency of small scale biomass combustion systems

Haslinger W, Schmidl C, Schwarz M, Verma VK, Hebenstreit B, Carlon E, Golicza L, Hartmann H, Brandt J, Weissinger A, Berger H, Wörgetter M. Annual efficiency of small scale biomass combustion systems, IEA Bioenergy Conference 2012, 13th-15th of November 2012, Vienna, Austria.

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Conference contributions | 2012

Arbeitsgruppe zum internationalen Erfahrungsaustausch der Probenahme und Analytik in Prozeßgasen

Kleinhappl M. Arbeitsgruppe zum internationalen Erfahrungsaustausch der Probenahme und Analytik in Prozeßgasen 2012, 22nd-23rd of October 2012, Hamburg, Germany.

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Conference contributions | 2012

AshMelT - Development of a Practical and Reliable Ash Melting Test for Biomass Fuels, in particular for Wood Pellets

Haslinger W, et al. AshMelT - Development of a Practical and Reliable Ash Melting Test for Biomass Fuels, in particular for Wood Pellets, 20th European Biomass Conference 2012, 18th-22nd of June 2012, Milano, Italy.

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Conference contributions | 2012

Assessment of online corrosion measurements in combination with fuel analysis, flue gas, aerosol and deposit measurements in a biomass CHP plant

Retschitzegger S, Brunner T, Obernberger I. Assessment of online corrosion measurements in combination with fuel analysis, flue gas, aerosol and deposit measurements in a biomass CHP plant, Conference Impacts of Fuel Quality on Power Production and Environment 2012, 23th-27th of September 2012, Puchberg, Austria.

Details

To systematically investigate high-temperature corrosion of superheaters in biomass combined heat and power (CHP) plants, a long-term test run (5 months) with online corrosion probes was performed in an Austrian CHP plant (28 MWNCV; steam parameters: 32 t/h at 480 °C and 63 bar) firing chemically untreated wood chips. Two corrosion probes were applied in parallel in the radiative section of the boiler at average flue gas temperatures of 880 and 780 °C using the steel 13CrMo4-5 for the measurements. Corrosion rates were determined for surface temperatures between 400 and 560 °C. The results show generally moderate corrosion rates and a clear dependence upon the flue gas temperatures and the surface temperatures of the corrosion probes, but no influence of the flue gas velocity has been observed. The data are to be used to create corrosion diagrams to determine maximum steam temperatures for superheaters in future plants, which are justifiable regarding the corrosion rate. Dedicated measurements were performed at the plant during the long-term corrosion probe test run to gain insight into the chemical environment of the corrosion probes. From fuel analyses, the molar 2S/Cl ratio was calculated with an average of 6.0, which indicates a low risk for high-temperature corrosion. Chemical analyses of aerosols sampled at the positions of the corrosion probes showed that no chlorine is present in condensed form at the positions investigated. Deposit probe measurements performed at the same positions and analyses of the deposits also showed only small amounts of chlorine in the deposits, mainly found at the leeward position of the probes. Subsequent to the test run, the corrosion probes have been investigated by means of scanning electron microscopy/energy-dispersive X-ray spectroscopy analyses. The results confirmed the deposit probe measurements and showed only minor Cl concentrations in the deposits and no Cl at the corrosion front. Because, in the case of Cl-catalyzed active oxidation, a layer of Cl is known to be found at the corrosion front, this mechanism is assumed to be not of relevance in the case at hand. Instead, elevated S concentrations were detected at the corrosion front, but the corrosion mechanism has not yet been clarified.


Conference contributions | 2012

Automatic CFD optimisation of biomass combustion plants

Shiehnejad A, Schulze K, Scharler R, Obernberger I. Automatic CFD optimisation of biomass combustion plants, 20th European Biomass Conference 2012, 18th-22nd of June 2012, Milano, Italy. 756-760.

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Conference contributions | 2012

Ökodesign-Maßnahmen für kleine Heizgeräte

Moser W, Haslinger W. Ökodesign-Maßnahmen für kleine Heizgeräte, 12. Industrieforum Pellets 2012, 9th-10th of October 2012, Berlin, Germany.

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Contributions at other events | 2012

Über die Aufbereitung biogener Gase mittels Adsorption

Mayer, T. Über die Aufbereitung biogener Gase mittels Adsorption, Ph.D. Thesis, Technische Universität Wien, Vienna, Austria, 2012.

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Conference contributions | 2012

Behandlungsoptionen einer MBA-Schwerfraktion - ökologischer und ökonomischer Vergleich

Meirhofer M, Ragoßnig AM, Rixrath D. Behandlungsoptionen einer MBA-Schwerfraktion - ökologischer und ökonomischer Vergleich, DepoTech 2012, 6th-9th of October 2012, Leoben, Austria.

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Conference contributions | 2012

BioCAT – Clean Air Technology for Small-Scale Biomass Combustion Systems

Haslinger W, et al. BioCAT – Clean Air Technology for Small-Scale Biomass Combustion Systems, 20th European Biomass Conference 2012, 18th-22nd of June 2012, Milano, Italy.

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