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Publikationen


Conference 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.

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Conference contributions | 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.

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In 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.


Contributions to trade journals | 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.

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Biodiesel (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.


Conference contributions | 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.

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Peer Reviewed Scientific Journals | 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.

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In 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.


Scientific Journals | 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

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Biomass 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.


Contributions at other events | 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.

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Conference contributions | 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.

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Conference contributions | 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.

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A 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 Scientific Journals | 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.

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Anaerobic 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.
 


Peer Reviewed Scientific Journals | 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

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An 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 contributions | 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.

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In 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.


Conference contributions | 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)

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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 | 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.

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Conference contributions | 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.

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Contributions to trade journals | 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.

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Conference contributions | 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.

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Conference contributions | 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.

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A 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.


Contributions to trade journals | 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.

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The 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 contributions | 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

A 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.


Contributions to trade journals | 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.

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Peer Reviewed Scientific Journals | 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.

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This 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 Presentations | 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.

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Peer Reviewed Scientific Journals | 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).

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Employing 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.