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Conference contributions | 2010

Annual efficiency determination of pellets boilers: Method, applications and new possibilities for the differentiation of the quality of pellets boilers

Haslinger W, Heckmann M, Schmidl C, Schwarz M. Annual efficiency determination of pellets boilers: Method, applications and new possibilities for the differentiation of the quality of pellets boilers, 10. Industrieforum Pellets, 7th-8th of September 2010, Stuttgart, Germany.

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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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Peer Reviewed Scientific Journals | 2016

Apparent kinetics of the catalyzed water-gas shift reaction in synthetic wood gas

Plaza A, Fail S, Cortés JA, Föttinger K, Diaz N, Rauch R, Hofbauer H. Apparent kinetics of the catalyzed water-gas shift reaction in synthetic wood gas. Chemical Engineering Journal. 1 October 2016;301: 222-228.

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Scientific Journals | 2017

Apparent kinetics of the water-gas-shift reaction in biomass gasification using ash-layered olivine as catalyst.

Krycaa J, Priščák J, Łojewskac J, Kuba M, Hofbauer H. Apparent kinetics of the water-gas-shift reaction in biomass gasification using ash-layered olivine as catalyst. Chemical Engineering Journal. 2018, 346: 113-119.

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Substitution of fossil fuels for production of electricity, heat, fuels for transportation and chemicals can be realized using biomass steam gasification in a dual fluidized bed (DFB).

Interaction between biomass ash and bed material in a fluidized bed leads to transformation of the bed particle due to enrichment of components from the biomass ash resulting in the development of ash layers on the bed particle surface. These ash-rich particle layers enhance the catalytic activity of the bed material regarding the water-gas-shift reaction and the reduction of tars.

The water-gas-shift reaction at conditions typical for dual fluidized bed biomass gasification at a temperature of 870 °C was investigated. Diffusion and heat transfer limitations were minimized using a lab-scale experimental set-up consisting of a gas mixing section and a quartz glass reactor in which the catalyst is investigated.

 

 

 


Conference contributions | 2013

Applicability and slag formation survey of different biomass fuel qualities in small scale combustion – a Substudy in the EU FP7-SME project AshMelT

Schwabl M, Feldmeier S, Nagelhofer K, Wopienka E, Haslinger W. Applicability and slag formation survey of different biomass fuel qualities in small scale combustion – a Substudy in the EU FP7-SME project AshMelT, 21st European Biomass Conference and Exhibition 2013, 3rd-7th of June 2013, Copenhagen, Denmark. p 1156-1159.

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Peer Reviewed Scientific Journals | 2019

Applicability of Fuel Indexes for Small-Scale Biomass Combustion echnologies, Part 2: TSP and NOx Emissions

Feldmeier S, Wopienka E, Schwarz M, Schön C, Pfeifer C. Applicability of Fuel Indexes for Small-Scale Biomass Combustion echnologies, Part 2: TSP and NOx Emissions. Energy & Fuels. 2019.33:11724-11730.

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Several studies pointed out that emission release is related to the concentration of particular elements in the fuel. Fuel indexes were developed to predict emissions of biomass combustion based on the elemental composition of the fuel. This study focuses on emissions of different biomass combustion technologies for domestic heating. Based on combustion tests with a wide range of fuel qualities we validated fuel indexes from the literature. We calculated the values for predicting total suspended particulate (TSP) matter and nitrogen oxide (NOx) emission of 39 biomass-derived fuels. Combustion tests conducted in 10 different small-scale appliances provided experimental data. The combustion technologies had a nominal load between 6 and 140 kWth. We measured TSP and NOx emissions during the stable phases of the experiments. The evaluation considered 529 combustion test intervals. All tested indexes for predicting the TSP corresponded well to the measured values. The correlation analysis confirmed that these indexes are associated with each other and are basically dominated by the concentration of potassium. The results regarding NOx emissions confirm previous findings from the literature by showing the typical nonlinear relation between nitrogen content of the fuel and NOx in the flue gas. Overall the comparison of the fuel indexes with the practical data indicated also an influence of the combustion technologies.


Peer Reviewed Scientific Journals | 2019

Applicability of the SOFC technology for coupling with biomass-gasifier systems: Short- and long-term experimental study on SOFC performance and degradation behaviour

Subotić V, Baldinelli A, Barelli L, Scharler R, Pongratz G, Hochenauer C, Anca-Couce A. Applicability of the SOFC technology for coupling with biomass-gasifier systems: Short- and long-term experimental study on SOFC performance and degradation behaviour. Applied Energy. 2019.256:113904

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Coupling biomass gasification with high temperature Solid Oxide Fuel Cells (SOFCs) is a promising solution to increase the share of renewables and reduce emissions. The quality of the producer gas used can, however, significantly impact the SOFC durability and reliability. The great challenge is to ensure undisturbed operation of such system and to find a trade-off between optimal SOFC operating temperature and system thermal integration, which may limit the overall efficiency. Thus, this study focuses on experimental investigation of commercial SOFC single cells of industrial size fueled with different representative producer gas compositions of industrial relevance at two relevant operating temperatures. The extensive experimental and numerical analyses performed showed that feeding SOFC with a producer gas from a downdraft gasifier, with hot gas cleaning, at an operating temperature of 750 °C represents the most favorable setting, considering system integration and the highest fuel utilization. Additionally, a 120 h long-term test was carried out, showing that a long-term operation is possible under stated operating conditions. Local degradation took place, which can be detected at an early stage using appropriate online-monitoring tools.


Peer Reviewed Scientific Journals | 2020

Applicability of Torrefied Sunflower Husk Pellets in Small and Medium Scale Furnaces

Kienzl N, Margaritis N, Isemin R, Zaychenko V, Strasser C, Kourkoumpas DS, Grammelis P, Klimov D, Larina O, Sytchev G, Mikhalev A. Applicability of Torrefied Sunflower Husk Pellets in Small and Medium Scale. Waste and Biomass Valorization. 2020;275:122882.

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The aim of this paper is to test the applicability of upgraded agricultural biomass feedstock such as torrefied sunflower husks during combustion in small and medium heating applications. Sunflower husk is formed in large quantities at enterprises producing sunflower oil and can be used as biofuel. However, big problems arise due to the low bulk density of husks and the rapid growth of ash deposits on the heating surfaces of boilers. In order to solve these problems, it was proposed to produce pellets from husks, and to subject these pellets to torrefaction. After torrefaction, net calorific value was increased by 29% while the risk of high temperature corrosion of boilers was reduced. Signs of ash softening neither occurred in combustion of raw nor in combustion of torrefied sunflower husk pellets. High aerosol emissions, already present in raw sunflower husk pellets, could not be mitigated by torrefaction. First combustion results at medium scale furnaces indicated that sunflower husk pellets (both raw and torrefied) in a commercial boiler < 400 kW, operated in a mode with low primary zone temperatures (< 850 °C), meet current emission limits. Regarding the future upcoming emission limits according to the European Medium Combustion Plant Directive, additional measures are required in order to comply with the dust limits.


Conference contributions | 2014

Applicability survey of different torrefied biomass fuels in small scale appliances

Feldmeier S, Schwabl M, Wopienka E, Strasser C, Haslinger W. Applicability survey of different torrefied biomass fuels in small scale appliances, 22nd European Biomass Conference 2014, 23rd-26th of June 2014, Hamburg, Germany. p 662-666.

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The torrefaction process is a promising key technology for biomass treatment. An improvement of the fuel properties, e.g. a higher gross calorific value and a resulting increased energy density, is expected. The changed fuel properties in terms of water repellence enable an improved storability. However, the modified fuel characteristics change the combustion behaviour of the fuel. Since small­scale pellet boilers mainly are dedicated to wood pellets, the applicability of torrefied fuel yet remains unclear. Within the EU FP7 project SECTOR, amongst others, the end­use application of torrefied biomass was investigated in several small scale appliances and the behaviour during the stationary operational conditions of the combustion process was assessed. The experimental design was divided in two parts: First, a survey of the combustion appliances was conducted in order to observe the influence of the changed fuel properties on the different boiler systems. Afterwards, the combustion behaviour of torrefied pellets made of different raw material quality was monitored by utilizing the test fuels and monitor the emission release. The results of these experimental series provide an initial indication for the feasibility of the utilization of several torrefied fuels in state­of­the­art pellet boilers.


Conference contributions | 2008

Application Fields of Sensor-based Sorting in Waste Management - Limits and Research Demand

Faist V, Ragossnig A. Application Fields of Sensor-based Sorting in Waste Management - Limits and Research Demand, ISWA Annual Congress 2008, 3rd-6th of November, Singapur.

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Conference contributions | 2014

Application of a Model Based Control Strategy at a Fixed Bed Biomass District Heating Plant

Zemann C, Heinreichsberger O, Gölles M, Brunner T, Dourdoumas N, Obernberger I. Application of a Model Based Control Strategy at a Fixed Bed Biomass District Heating Plant. 22nd European Biomass Conference and Exhibition Proceedings. 2014;1698-1705.

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Peer Reviewed Scientific Journals | 2015

Application of an empirical model in CFD simulations to predict the local high temperature corrosion potential in biomass fired boilers.

Gruber T, Scharler R, Obernberger I. Application of an empirical model in CFD simulations to predict the local high temperature corrosion potential in biomass fired boilers. Biomass and Bioenergy. Volume 79, August 2015, Pages 145-154.

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To gain reliable data for the development of an empirical model for the prediction of the local high temperature corrosion potential in biomass fired boilers, online corrosion probe measurements have been carried out. The measurements have been performed in a specially designed fixed bed/drop tube reactor in order to simulate a superheater boiler tube under well-controlled conditions. The investigated boiler steel 13CrMo4-5 is commonly used as steel for superheater tube bundles in biomass fired boilers. Within the test runs the flue gas temperature at the corrosion probe has been varied between 625 °C and 880 °C, while the steel temperature has been varied between 450 °C and 550 °C to simulate typical current and future live steam temperatures of biomass fired steam boilers. To investigate the dependence on the flue gas velocity, variations from 2 m·s−1 to 8 m·s−1 have been considered. The empirical model developed fits the measured data sufficiently well. Therefore, the model has been applied within a Computational Fluid Dynamics (CFD) simulation of flue gas flow and heat transfer to estimate the local corrosion potential of a wood chips fired 38 MW steam boiler. Additionally to the actual state analysis two further simulations have been carried out to investigate the influence of enhanced steam temperatures and a change of the flow direction of the final superheater tube bundle from parallel to counter-flow on the local corrosion potential.


Contributions to trade journals | 2013

Application of novel and advanced fuel characterization tools for the combustion related characterization of different wood/Kaolin and straw/Kaolin mixtures

Sommersacher P, Brunner T, Obernberger I, Kienzl N, Kanzian W. Application of novel and advanced fuel characterization tools for the combustion related characterization of different wood/kaolin and straw/kaolin mixtures. Energy and Fuels. 2013;27(9):5192-206.

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The increased demand for energy from biomass enforces the utilization of new biomass fuels (e.g., energy crops, short-rotation coppices, as well as wastes and residues from agriculture and the food industry). Compared to conventional wood fuels, these new biomass fuels usually show considerably higher ash contents and lower ash sintering temperatures, which leads to increased problems concerning slagging, ash deposit formation, and particulate matter emissions. One possibility to combat these problematic behaviors is the application of fuel additives such as kaolin. In contrast to the usual approach for the application of additives based on an experimental determination of an appropriate additive ratio, this study applies novel and advanced fuel characterization tools for the characterization of biomass/kaolin mixtures. In the first step the pure biomass fuels (softwood from spruce and straw) and the additive were chemically analyzed. On the basis of the analysis theoretical mixing calculations of promising kaolin ratios were conducted. These theoretical mixtures were evaluated with fuel indexes and thermodynamic equilibrium calculations (TEC). Fuel indexes provide the first information regarding high temperature corrosion (2S/Cl) and ash melting tendency (Si + P + K)/(Ca + Mg + Al). TEC can be used for a qualitative prediction of the release of volatile and semivolatile elements (K, Na, S, Cl, Zn, Pb) and the ash melting behavior. Moreover, selected mixtures of spruce and straw with kaolin were prepared for an evaluation and validation of the release behavior of volatile and semivolatile ash forming elements with lab-scale reactor experiments. The validation of the ash melting behavior was conducted by applying the standard ash melting test. It could be shown that the new approach to apply novel and advanced fuel characterization tools to determine the optimum kaolin ratio for a certain biomass fuel works well and thus opens a new and targeted method for additive evaluation and application. In addition, it helps to significantly reduce time-consuming and expensive testing campaigns. © 2013 American Chemical Society.


Conference contributions | 2015

Application of numerical modelling to biomass grate furnaces

Mehrabian R, Shiehnejadhesar A., Scharler R. Application of numerical modelling to biomass grate furnaces. Internation conference on advances in mechanical engineering, Istanbul 2015.

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The direct combustion of the biomass is the most advanced and mature technology in the field of energetic biomass utilisation. The legislations on the amount of emitted pollutants and the plant efficiency of biomass combustion systems are continually being restricted. Therefore constant improvement of the plant efficiency and emission reduction is required Numerical modelling is gaining increasing importance for the development of biomass combustion technologies. In this paper an overview about the numerical modelling efforts deal with the most relevant phenomena in biomass grate firing systems is given. The numerical modelling results in a deeper understanding of the underlying processes in biomass combustion plants. Therefore, it leads to a faster and safer procedure of development of a new technology.


Conference contributions | 2019

Aqueous phase reforming of Fischer-Tropsch water fraction

Zoppi G, Pipitone G, Gruber H, Weber G, Reichhold A, Pirone R, Bensaid S. Aqueous phase reforming of Fischer-Tropsch water fraction. ICPS 2019.

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Scientific Journals | 2020

Aqueous phase reforming of pilot-scale Fischer-Tropsch water effluent for sustainable hydrogen production

Zoppi G, Pipitone G, Gruber H, Weber G, Reichhold A, Pirone R, Bensaid S. Aqueous phase reforming of pilot-scale Fischer-Tropsch water effluent for sustainable hydrogen production. Catalysis Today.2020.

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Fischer-Tropsch (FT) synthesis produces an aqueous stream containing light oxygenates as major by-product. The low carbon concentration of the organics makes its thermal recovery unprofitable. Thus, novel processes are needed to utilize this waste carbon content. In this work, the aqueous phase reforming of the wastewater obtained from a 15 kWth Fischer-Tropsch plant was explored as a promising process to produce hydrogen at mild temperatures. The FT product water was firstly characterized and afterward subjected to the reforming at different reaction temperatures and time, using a platinum catalyst supported on activated carbon. It was observed that, besides activity, the selectivity towards hydrogen was favored at higher temperatures; equally, increasing the reaction time allowed to obtain the total conversion of most molecules found in the solution, without decreasing the selectivity and reaching a plateau at 4 hours in the hydrogen productivity. In order to get more insights into the reaction mechanism and product distribution derived from the APR of FT product water, several tests were performed with single compounds, finding characteristic features. The importance of the position of the hydroxyl group in the molecule structure was highlighted, with secondary alcohols more prone to dehydrogenation pathways compared to primary alcohols. Moreover, no interference among the substrates was reported despite the mixture is constituted by several molecules: in fact, the results obtained with the real FT product water were analogous to the linear combination of the single compound tests. Finally, the reuse of the catalyst showed no appreciable deactivation phenomena.


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 Papers | 2017

Ash and bed material research in dual fluidized bed gasification of biomass in lab- and industrial-scale

Kuba M, Hofbauer H. Ash and bed material research in dual fluidized bed gasification of biomass in lab- and industrial-scale. 25th European Biomass Conference & Exhibition (oral presentation). June 2017, Stockholm, Sweden.

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Conference contributions | 2014

Ash melting behaviour of solid biofuels in residential pellet boilers

Schwabl M, Feldmeier S, Wopienka E, Haslinger W, Dahl J, Jensen TB, Hartmann H, Schön C, Boman C, Boström D. Pellets Workshop “Ash melting behaviour of solid biofuels in residential pellet boilers” (held held during the Central European Biomass Conference 2014), 15th-18th of January, Graz, Austria, 2014.

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Peer Reviewed Scientific Journals | 2021

Ash transformation during single-pellet gasification of agricultural biomass with focus on potassium and phosphorus

Hedayati A, Sefidari H, Boman C, Skoglund N, Kienzl N, Öhman M. Ash transformation during single-pellet gasification of agricultural biomass with focus on potassium and phosphorus. Fuel Processing Technology. 15 June 2021.217:106805

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Agricultural biomasses and residues can play an important role in the global bioenergy system but their potential is limited by the risk of several ash-related problems such as deposit formation, slagging, and particle emissions during their thermal conversion. Therefore, a thorough understanding of the ash transformation reactions is required for this type of fuels. The present work investigates ash transformation reactions and the release of critical ash-forming elements with a special focus on K and P during the single-pellet gasification of different types of agricultural biomass fuels, namely, poplar, grass, and wheat grain residues. Each fuel was gasified as a single pellet at three different temperatures (600, 800, and 950 °C) in a Macro-TGA reactor. The residues from different stages of fuel conversion were collected to study the gradual ash transformation. Characterization of the residual char and ash was performed employing SEM-EDS, XRD, and ICP with the support of thermodynamic equilibrium calculations (TECs). The results showed that the K and P present in the fuels were primarily found in the residual char and ash in all cases for all studied fuels. While the main part of the K release occurred during the char conversion stage, the main part of the P release occurred during the devolatilization stage. The highest releases – less than 18% of P and 35% of K – were observed at the highest studied temperature for all fuels. These elements were present in the residual ashes as K2Ca(CO3)2 and Ca5(PO4)3OH for poplar; K-Ca-rich silicates and phosphosilicates in mainly amorphous ash for grass; and an amorphous phase rich in K-Mg-phosphates for wheat grain residues.


Peer Reviewed Scientific Journals | 2022

Ash transformation during single-pellet gasification of sewage sludge and mixtures with agricultural residues with a focus on phosphorus

Hannl TK, Häggström G, Hedayati A, Skoglund N, Kuba M, Marcus Öhman. Ash transformation during single-pellet gasification of sewage sludge and mixtures with agricultural residues with a focus on phosphorus. Fuel Processing Technology. March 2022.227:107102.

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The recovery of phosphorus (P) from sewage sludge ashes has been the focus of recent research due to the initiatives for the use of biogenic resources and resource recovery. This study investigates the ash transformation chemistry of P in sewage sludge ash during the co-gasification with the K-Si- and K-rich agricultural residues wheat straw and sunflower husks, respectively, at temperatures relevant for fluidized bed technology, namely 800 °C and 950 °C. The residual ash was analyzed by ICP­AES, SEM/EDS, and XRD, and the results were compared to results of thermochemical equilibrium calculations. More than 90% of P and K in the fuels were retained in the residual ash fraction, and significant interaction phenomena occurred between the P-rich sewage sludge and the K-rich ash fractions. Around 45–65% of P was incorporated in crystalline K-bearing phosphates, i.e., K-whitlockite and CaKPO4, in the residual ashes with 85–90 wt% agricultural residue in the fuel mixture. In residual ashes of sewage sludge and mixtures with 60–70 wt% agricultural residue, P was mainly found in Ca(Mg,Fe)-whitlockites and AlPO4. Up to about 40% of P was in amorphous or unidentified phases. The results show that gasification provides a potential for the formation of K-bearing phosphates similar to combustion processes.


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 | 2013

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

Feldmeier S, Schwabl M, Höftberger E, Wopienka E. AshMelT – Development of a Practical and Reliable Ash Melting Test for Biomass Fuels, in particular for Wood Pellets, European Pellets Conference 2013, 27th-28th of February 2013, Wels, Austria.

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Conference contributions | 2015

AshMelT Project Background – Why this work was necessary

Schwabl M, Wopienka E. AshMelT Workshop “AshMelT Project Background – Why this work was necessary” (held during de World Sustainable Energy Days 2015), 25th-27th of February, Wels, Austria, 2015.

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Other Presentations | 2015

Aspects of microalgal biomass as feedstock in biogas plants

Gruber M, Zohar E, Jerney J, Ludwig I, Bochmann G, Nussbaumer L, Montgomery L, Fuchs W, Drosg B, Schöpp T, Obbard JP. Aspects of microalgal biomass as feedstock in biogas plants, 23rd European Biomass Conference 2015, 1st-4th of June 2015, Vienna, Austria. (visual presentation)

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