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Technical Reports | 2020

Test Report - Lean Gas Test: Operation of a Stirling engine with landfill gas

Stressler H, Aigenbauer S. Test Report - Lean Gas Test: Operation of a Stirling engine with landfill gas. Projektbericht. February 2020

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Technical Reports | 2020

Test Report - Lean Gas Test: Operation of a Stirling engine with sewage gas

Stressler H, Aigenbauer S. Test Report - Lean Gas Test: Operation of a Stirling engine with sewage gas. Projektbericht. February 2020

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Conference contributions | 2012

The actual need of a guideline for sampling and analysis of chemical matter (not tars) from product gas, pyrolysis gas and synthesis gas

Zeisler J, Kleinhappl M, Martini S, Neubauer Y. The actual need of a guideline for sampling and analysis of chemical matter (not tars) from product gas, pyrolysis gas and synthesis gas, 20th European Biomass Conference 2012, 18th-22nd of June 2012, Milano, Italy. p 919-925.

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Due to the increasing number of different online and offline methods and procedures for sampling at gasification and pyrolysis plants a comparison of the measured values is difficult. About the sampling of tars already a number of detailed guidelines and a common approach are established [2]. In terms of discrete chemical impurities the missing of a guideline for sampling at biomass¬ plants is an obstacle for implementing sampling systems in new plants or experimental assemblies. Nevertheless the knowledge is available at several institutions but it has to be collected. Within this paper the basic challenges of sampling are mentioned, the system at Bioenergy2020+ is explained in detail and about the parameters NH3, H2S & HCN useful results of optimisation are reported. This status should help to point out the need of a reliable library of methods. According the first systematisation of offline and online sampling respectively detection a table of application is proposed. The detailed knowledge for this will be treated and exchanged within an established working group which should lead to a guideline (at least methods library) for sampling of trace components as described.


Peer Reviewed Scientific Journals | 2015

The behavior of biomass and char particles in a dual fluidized bed gasification system

Kraft S, Kuba M, Hofbauer H. The behavior of biomass and char particles in a dual fluidized bed gasification system. Powder Technology 2018;338:887-897.

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Biomass gasification in fluidized beds is a complex process in which particles occur in a wide range of size and density. In this paper, the mixing behavior of the char, biomass and bed material in a gasification reactor of a typical dual fluidized bed (DFB) system was investigated in a cold flow model. Experiments with ternary mixtures were performed in which the size and the density of the used particles were varied. For the experiments, a cold flow model was constructed with a full bed material recirculation loop, similar to DFB systems. Experiments revealed that at low fluidization velocities, the smaller char particles and biomass particles occur more preferentially in the bed material recirculation stream. If the fluidization velocities are increased, this tendency diminishes. Furthermore, the experiments showed that the mass fraction of biomass particles in the recirculation stream is always higher than that of the lighter char particles. It is also shown that the current design of the gasification reactor in DFB systems is not optimal. A way to overcome this issue in existing plants is presented.

Contributions to trade journals | 2014

The Biomass Technology Roadmap of the RHC-Platform: Priorities for high efficient large-scale CHP units

Grammelis P, Goodwin N, Alakangas E, Haslinger W, Karampinis E. The Biomass Technology Roadmap of the RHC-Platform: Priorities for high efficient large-scale CHP units. VGB PowerTech. 2014;6:74-79.

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Die europäische Technologie-Plattform für Heizen und Kühlen mit erneuerbaren Energien (RHC-Plattform, www.rhc-platform.org) fördert die Forschung und Entwicklung bei der Wärme- und Kälteproduktion aus erneuerbaren Energiequellen in der EU. Die verschiedenen Endanwendungen (Strom und/oder Bereitstellung von Wärme, Kraftstoff) setzen eine Verdoppelung der Biomassenutzung voraus, um die 20-20-20-Ziele der EU zu erreichen. Neue Ressourcen müssen erschlossen, mobilisiert und der Wirkungsgrad der Umwandlungsprozesse gesteigert werden. In Biomasse-Heizkraftwerken sowie Heizwerken werden derzeit mehr als ein Drittel des gesamten Biomasseaufkommens eingesetzt. Dies führt zu neuen, gemeinsamen Herausforderungen für den Strom- und Wärmesektor.
Das Biomasse-Panel der RHC-Plattform hat Schwerpunkte für Forschung und Entwicklung definiert, um bestimmte Kennzahlen für Biomassewertschöpfungsketten zu erreichen. Der vorliegende Beitrag stellt die Prioritäten für die Bestandteile der Wertschöpfungsketten vor, die relevant für den Strombereich sind:
a) nachhaltige und kosten-effiziente Biomasseversorgungsketten, b) thermisch behandelte Biomasse-Brennstoffe und c) hoch-effiziente KWK-Anlagen.
Herausforderungen für den Anlagenbetrieb sind Brennstoffflexibilität, Wirkungsgraderhöhung über den vollen Lastbereich, Betrieb mit variablen Brennstoffen und Qualitäten bei variablen Lastzuständen, höhere Betriebsparameter für Dampf und andere Wärmeträger, höhere Anlagenverfügbarkeit, Reduktion von unerwünschten gas- und partikelförmigen Emissionen und schließlich die Ascheverwertung.
 


Conference contributions | 2020

The Contribution of advanced renewable transport fuels to transport decarbonisation in 2030 and beyond

Bacovsky D, Laurikko J. The Contribution of advanced renewable transport fuels to transport decarbonisation in 2030 and beyond. 28th European Biomass Conference and Exhibition (oral presentation) 2020.

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In the light of climate change, there is an urgent need to decarbonize our societies. The transport sector is specifically challenging, as transport demand is still growing, and so are the sector´s GHG emissions. Several countries have set ambitious national targets for GHG reduction in the transport sector. These are often backed with policy measures for implementation of both advanced renewable transport fuels and electrification.
In a project set up jointly by two Technology Collaboration Programmes of the International Energy Agency, namely the IEA Bioenergy TCP and the Advanced Motor Fuels TCP, the contribution that advanced renewable transport fuels should make to the decarbonisation of the transport sector is assessed by means of country-specific assessments.


Peer Reviewed Scientific Journals | 2022

The effect of the presence of water on sulfur removal capacity during H2S removal from syngas using ZnO adsorbent

Dogan C, Martini S, Rets hitzegger S, Cetin B. The effect of the presence of water on sulfur removal capacity during H2S removal from syngas using ZnO adsorbent. Environmental Technology. 15 May 2022.

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Compared to extensive studies on affecting parameters in sulfur removal with ZnO adsorbents from coal gasification syngas, similar studies conducted for biomass gasification syngas (BGS) are quite rare. Thus, considering the BGSs with high water content, this study was performed to investigate the effect of H2O presence in syngas on sulfur removal capacity (SRC) of ZnO adsorbents. Initially, the effect of gas composition and temperature on SRC in binary gas mixture was investigated. While H2O decreased the SRC, as expected, the highest reduction in the capacity occurred in the CO–H2S gas mixture due to observed COS formation. Second, the SRCs and resulting COS formation were compared for synthetic syngas mixtures having different water contents and for different amounts of adsorbents. Finally, the separate and combined effects of temperature and H2O on SRC and COS formation in synthetic syngas were investigated by comparing SRCs of typical syngas under wet and dry conditions. The results showed that increasing the amount of adsorbent and temperature results in higher SRC due to a reduction in COS formation through the reactions of COS with H2 and H2O. This indicates that it is critical to control the residence time of syngas and temperature to reduce COS formation during ZnO adsorption.


Peer Reviewed Scientific Journals | 2020

The effect of the reaction equilibrium on the kinetics of gas-solid reactions — A non-parametric modeling study.

Birkelbach F, Deutsch M, Werner A. The effect of the reaction equilibrium on the kinetics of gas-solid reactions — A non-parametric modeling study. Renewable Energy 2020.152:300-307.

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The viability of thermochemical energy storage for a given application is often determined by the reaction kinetics under process conditions. For high exergetic efficiency the process needs to operate in close proximity to the reaction equilibrium. Thus, accurate kinetic models that include the effect of the reaction equilibrium are required.

In the present work, different parametrization methods for the equilibrium term in the General Kinetic Equation are evaluated by modeling the kinetics of two reaction systems relevant for thermochemical energy storage (CaC2O4 and CuO) from experimental data. A non-parametric modeling method based on tensor decompositions is used that allows for a purely data driven assessment of different parametrization methods.

Our analysis shows that including a suitable equilibrium term is crucial. Omitting the equilibrium term when modeling formation reactions can lead to seemingly negative activation energies. Our tests also show that for formation reactions, the reaction rate decreases much faster towards the equilibrium than theory predicts. We present an empirical modeling approach that can predict the reaction rate of gas-solid reactions, regardless of the shortcomings of theory. In this way, non-parametric modeling offers a powerful tool for applied research and may contribute to the advancement of the thermochemical energy storage technology.


Technical Reports | 2018

The Green P - Nutzung von städtischen Verkehrsflächen für die Produktion von Biomasse

Lichtenegger K, Meixner K, Riepl R, Schipfer F, Zellinger M. The Green P - Nutzung von städtischen Verkehrsflächen für die Produktion von Biomasse. BMVIT, Schriftenreihe 25/2018.

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Conference contributions | 2018

The Green Parking Area – Utilization of urban parking areas for cultivation of algae

Zellinger M, Riepl R, Lichtenegger K, Meixner K, Drosg B, Enigl M, Theuretzbacher F, Schipfer F. The Green Parking Area – Utilization of urban parking areas for cultivation of algae. presentation at the WSED, Wels, Austria, 01. March 2018.

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The present study examines the possible use of urban and rural traffic areas for producing biomass. Many of those areas (for example, parking lots at cinemas and shopping centers) are only intensively used during certain times. Most of the time those areas remain empty.
At the same time a major problem for large-scale implementation of renewable energy is the massive land use resulting from limited energy density of solar radiation and, in case of biomass production, low efficiency for utilization of solar radiation by plants. Additionally, renewable energies are often criticized for the fact that they require areas, which could also be used for food and feed production.
Therefore, it is an attractive idea to use some of the traffic areas that are lost for the ecosystem anyway for biomass production. This approach is novel that no data have been available yet. The aim of this work was therefore to develop technical solutions, to quantify the technical potential for this type of biomass production and, subsequently, for energy supply, based on data on the area utilization, climatic data and known properties of microalgae.
The work deals with the question of the technical potential for this approach in Austria. This question is
answered by a survey of the area data in Austria, the elaboration of technical systems for a possible implementation, as well as by calculating the biomass potential, based on simulation results. The data have been collected, analyzed and evaluated in a comprehensive literature search. The potential analysis provides an overview of the distribution of traffic areas in Austria and the resulting biomass potential. Thus, a list of possible areas including biomass and energy quantities is available.


Conference contributions | 2017

The Green Parking Area – Utilization of urban parking areas for cultivation of microalgae

Zellinger M, Riepl R, Lichtenegger K, Meixner K, Drosg B, Enigl M, Theuretzbacher F, Schipfer F. The Green Parking Area – Utilization of urban parking areas for cultivation of microalgae. Presentation at the Eco City Summit 2017, Melbourne, Australia, 17. June 2017.

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Other Presentations | 2017

The Green Parking Space – Nutzung von städtischen Verkehrsflächen für die Produktion von Biomasse

Schipfer F, Lichtenegger K, Zellinger M et al. The Green Parking Space – Nutzung von städtischen Verkehrsflächen für die Produktion von Biomasse. Präsentation. First Vienna Vertical Farming Meetup 01.03.2017, Wien.

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Peer Reviewed Scientific Journals | 2020

The impact of project financing in optimizing microgrid design

Pecenak ZK, Mathiesen P, Fahy K, Cannon C, Ayandele E, Kirk TJ, Stadler M. The impact of project financing in optimizing microgrid design. Journal of Renewable and Sustainable Energy. November 2020. 12:026187.

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A disconnect between real world financing and technical modeling remains one of the largest barriers to widespread adoption of microgrid technologies. Simultaneously, the optimal design of a microgrid is influenced by financial as well as technical considerations. This paper articulates the interplay between financial and technical assumptions for the optimal design of microgrids and introduces a design approach in which two financing structures drive an efficient design process. This approach is demonstrated on a descriptive test case, using well accepted financial indicators to convey project success. The major outcome of this paper is to provide a framework which can be adopted by the industry to relieve one of the largest hurdles to widespread adoption, while introducing multiple debt financing models to the literature on microgrid design and optimization. An equally important outcome from the test case, we provide several points of intuition on the impact of varying financing terms on the optimal solution.


Peer Reviewed Scientific Journals | 2016

The influence of oxygen availability on off-gassing rates of emissions from stored wood pellets

Meier F, Sedlmayer I, Emhofer W, Wopienka E, Schmidl C, Haslinger W, Hofbauer H. The influence of oxygen availability on off-gassing rates of emissions from stored wood pellets. Energy & Fuels. 18 February 2016;30(2): 1006-1012.

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The phenomenon of off-gassing from wood pellets during storage has been the cause of several, in some cases fatal, accidents due to toxic atmospheres in storages. To optimize safety measures the nature of the responsible processes needs to be clarified. In this study the impact of O2 availability, which is a decisive factor for the presumed oxidation of fatty acids, is pointed out. Off-gassing rates of CO, CO2, VOC, and CH4 of pellets at relatively constant O2 levels of approximately 35%, 20%, and <1% over a period of 20 d at approximately 295 K were investigated. For this purpose 7 kg of spruce pellets was stored under simulated ventilation of the atmosphere in a 31 L tank. Gas concentrations were determined every 24 h by GC-FID/TCD. Compared to the mean emission rates at 35% O2 of CO (0.22 mg kg–1pelletsd.b. in 24 h) and CO2 (0.76 mg kg–1pelletsd.b. in 24 h) the lowest O2 concentration of <1% resulted in a significant reduction of off-gassing rates of 40% for both gases. In contrast the release rates of VOCs and also CH4 decreased with the higher O2 concentration (0.035 to 0.025 mg kg–1pelletsd.b. in 24 h; 0.0085 to 0.0061 mg kg–1pelletsd.b. in 24 h), presumably, because of increased onward reactions to CO and CO2. Since off-gassing was not prevented by the lack of O2 (<1% O2-trial) it is assumed that the O2 required for the reactions originated from the biomass itself. During the storage of pellets at 20% O2, emission rates of CO (0.18 mg kg–1pelletsd.b. in 24 h) and CO2 (0.79 mg kg–1pelletsd.b. in 24 h) at the start decreased by more than 20% and those for VOCs (0.032 mg kg–1pelletsd.b. in 24 h) by almost 30% after 3 weeks. It can be assumed that in ventilated storages the reactivity and thus a potential risk from off-gases from wood pellets decreases considerably in only a few weeks. The effects of aging, in terms of declining reactivity at relatively constant tank conditions, on off-gassing rates could be clarified for the first time. A realistic development of the decline of reactivity of the material itself could be determined.


Conference contributions | 2015

The Influence of Wood Pellet Prices on Heat Generation Costs of Alternative Heating Systems

Kristöfel C, Strasser C, Schmid E. The Influence of Wood Pellet Prices on Heat Generation Costs of Alternative Heating Systems, 23rd European Biomass Conference 2015, 1st-4th of June 2015, Vienna, Austria. (oral presentation)

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Peer Reviewed Scientific Journals | 2016

The interplay of self-reflection, social interaction and random events in the dynamics of opinion flow in two-party democracies

Lichtenegger K, Hadzibeganovic T. The interplay of self-reflection, social interaction and random events in the dynamics of opinion flow in two-party democracies. International Journal of Modern Physics C. 1 May 2016;27(5).

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We propose a continuous process opinion formation model to study the dynamics of a multi-level relationship between voters, political parties, and facts in two-party democratic elections. In our model, opinions can take any real value between two extremes and an unaligned, moderate opinion state without a preference. Starting with a random opinion configuration, individual voter opinions evolve and change over time due to self-reflection, inter-personal communication, external media influence, and noise. Parties are influenced by their own ideologies, facts, and voters’ opinions. Elections are held periodically and the party that is closer in opinion to the majority of voters forms the new government. The government policy is then expected to be in proximity to the voter opinions and the policies of the currently ruling political party. We analyze the tension of opinions as a measure of how dramatically opinions can disagree within a given sample of voters and the success of the government and parties as the degree of coincidence between the policies and facts. Our model generates realistic quasi-periodic alternations between incumbents and challengers that are typical for two-party systems. Moreover, our model shows that relative to other voters’ strategies, conscious voting can lead to more successful governments of not only fact-oriented but also pragmatic and balanced political parties, irrespective of the strategies of the competing opposition parties. In addition, our simulations uncover several interesting features including less victories for strictly ideological or fact-oriented parties unless they include some aspects of populism or pragmatism. In this sense, our model can also describe situations where election outcomes are not necessarily based on votes for the current programs of competing parties and their placement on relevant issues, but instead result from voters’ dissatisfaction with the previous government and the votes against it.


Read More: http://www.worldscientific.com/doi/abs/10.1142/S0129183116500650

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.


Conference contributions | 2020

The modification of biogenic carbon-rich solids opens new possibilities

Martini S, Kienzl N, Ortner M, Loipersböck J. The modification of biogenic carbon-rich solids opens new possibilities. Biochar Workshop @ 6th Central European Biomass Conference (oral presentation). 2020.

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Contributions to trade journals | 2012

The positive effects of bed material coating on tar reduction in a dual fluidized bed gasifier

Kirnbauer F, Wilk V, Kitzler H, Kern S, Hofbauer H. The positive effects of bed material coating on tar reduction in a dual fluidized bed gasifier. Fuel. 2012;95:553-562.

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The utilization of biomass for the substitution of fossil fuels to reduce greenhouse gas emissions in biomass steam gasification plants is a promising technology for the production of electricity, heat, and fuels for transportation. Experience from industrial scale dual fluidized bed steam gasification plants showed a modification of the bed material due to the interaction of the bed material (olivine) with biomass ash components and additives. In this paper the influence of bed material modification on the gasification properties of used olivine from an industrial scale plant in Güssing is compared with the case of fresh olivine. The trials were carried out under similar conditions in a pilot plant at the Vienna University of Technology. The pilot plant trials showed an increase in hydrogen and carbon dioxide in the product gas with the used bed material while the content of carbon monoxide in the product gas decreased. The exothermal water–gas shift reaction is enhanced by the used bed material, resulting in a lower energy demand for the gasification. Tar content was decreased by around 80% for tars detected by gas chromatography–mass spectrometry (GCMS) and the composition of the tar showed less components during the trial with used bed material.

The results obtained with the used bed material at the 100 kW pilot plant are in good agreement with those for the 8 MW industrial plant in Güssing, confirming good scale-up properties from the 100 kW plant to industrial scale plants.


Conference contributions | 2010

The present state and future development of industrial biomass combustion for heat and power generation

Obernberger I. The present state and future development of industrial biomass combustion for heat and power generation, ASME-ATI-UIT 2010 Conference on Thermal and Environmental Issues in Energy Systems 2010, 16th-19th of May 2010, Sorrento, Italy.

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Conference Papers | 2021

The robust exact differentiator toolbox revisited: Filtering and discretization features.

Andritsch B, Horn M, Koch S, Niederwieser H, Wetzlinger M, Reichhartinger M. The robust exact differentiator toolbox revisited: Filtering and discretization features. in 2021 IEEE International Conference on Mechatronics, ICM 2021. Institute of Electrical and Electronics Engineers. 2021. 9385675 https://doi.org/10.1109/ICM46511.2021.9385675

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An extended version of a Simulink ® -block providing on-line differentiation algorithms based on discretized sliding-mode concepts is presented. Based on user-specified settings it computes estimates of the time-derivatives of the input signal up to order ten. Different discrete-time estimation algorithms as well as optional filtering properties can be selected. The paper includes an overview of the implemented algorithms, a detailed explanation of the developed Simulink ® -block and two examples. The first example illustrates the application of the toolbox in a numerical simulation environment whereas the second one shows results obtained via an electrical laboratory setup.


Conference Papers | 2015

The role of 1H-indene in product gas of biomass gasification

Kuba M, Kirnbauer F, Hofbauer H. The role of 1H-indene in product gas of biomass gasification. International Bioenergy Exhibition and Asian Bioenergy Conference 2015. October 2015, Shanghai, China.

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Peer Reviewed Scientific Journals | 2015

The Role of Leak Air in a Double-Wall Chimney

Lichtenegger K, Hebenstreit B, Pointner C, Schmidl C, Höftberger E. The role of leak air in a double-wall chimney. Heat Mass Transfer. 2015;51(6):787-94.

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In modern buildings with tight shells, often room-independent air supply is required for proper operation of biomass stoves. One possibility to arrange this supply is to use a double-wall chimney with flue gas leaving through the pipe and fresh air entering through the annular gap. A one-dimensional quasi-static model based on balance equations has been developed and compared with experimental data. Inclusion of leak air is crucial for reproduction of the experimental results. © 2014, Springer-Verlag Berlin Heidelberg.


Peer Reviewed Scientific Journals | 2016

The Virtual Biomass Grate Furnace - An Overall CFD Model for Biomass Combustion Plants

Ali Shiehnejadhesar, Ramin Mehrabian, Robert Scharler, Christoph Hochenauer. The Virtual Biomass Grate Furnace - An Overall CFD Model for Biomass Combustion Plants. 24rd European Biomass Conference & Exhibition (poster).

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This paper presents the virtual biomass grate furnace, which comprises of comprehensive CFD models of all relevant processes for the simulation of biomass grate furnaces. The models consist of a 3D packed bed model, a gas phase combustion model for laminar to highly turbulent flows and a model to account for the influence of the flue gas streaks arising from the fuel bed in the freeboard. The simulation results of a 20 kW underfeed stoker furnace show that the overall CFD model is able to provide valuable insight on the processes occurring in the packed bed and freeboard and their interactions.


Contributions to trade journals | 2016

The wood pellet market in Austria: A structural market model analysis

Christa Kristöfel, Christoph Strasser, Erwin Schmid, Ulrich B. Morawetz, The wood pellet market in Austria: A structural market model analysis, Energy Policy, Volume 88, January 2016, Pages 402-412,

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