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Conference Papers | 2016

Cold flow modelling of char concentration in the recirculated bed material stream of a dual fluidized bed steam gasification system

Kraft S, Kirnbauer F, Hofbauer H. Cold flow modelling of char concentration in the recirculated bed material stream of a dual fluidized bed steam gasification system. Fluidization XV. 22-27 May 2016, Quebec, Canada.

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The dual fluidized bed (DFB) steam gasification technology of biomass was developed at Vienna University of Technology and is well-established for transforming biomass into a product gas which can be used for further applications. The DFB steam gasification reactor consists of a gasification chamber (bubbling bed, fluidized with steam) and a combustion chamber (turbulent bed, fluidized with air). Biomass is fed into the gasification chamber and gets in contact with the bed material, typically Olivine, at about 840°C. The released volatiles leave the gasification reactor as product gas. A part of the solid residue, called char, flows with the bed material via a chute to the combustion chamber where it is burnt with air. The bed material is heated up, separated from the flue gas stream in a cyclone and flows back to the gasification reactor via a loop seal where it provides the heat for devolatilization and drying of the biomass. The movement of the char is crucial since a sufficient amount has to flow to the combustion chamber and burn to provide enough energy for bed material heat-up. Up to now little is known about the char concentration in the bed material recirculation stream (or short recirculation stream) and its influencing variables. Therefore, a cold flow model, operated with ambient air, was constructed to study the influence of various parameters on the char concentration in the recirculation stream. Bronze is used as bed material since is matches closest to the scaling criteria. The char is also scaled; polyethylene is used as model char.

The cold flow model, see Figure 1 for the flowsheet, consists of a “gasification chamber” which corresponds to the gasification chamber in the hot plant and is as well operated as a bubbling bed. Via a chute the recirculation stream moves to a rotary valve which enables to set a fixed recirculation rate and make it independent from the following pneumatic conveying. Then, gas and solids are separated in a cyclone and the recirculation stream finally flows back to the gasification chamber. After the loop seal samples are taken for investigation of the model char concentration in the recirculation stream. In the present study the influence of fluidization rate in the gasification chamber, bed material recirculation rate and model char mass in the system on the char concentration in the recirculation stream are investigated. It was found that the model char particles show a flotsam behavior. Higher fluidization rates increase the model char concentration in the recirculation stream because of better mixing, whereas the bed material recirculation rate has only little influence. Doubling and tripling the overall char mass in the system did not lead to a doubling or tripling model char concentration in the recirculation stream. The present observations are helping to better understand the ongoing phenomena inside of the dual fluidized bed gasification reactor and provide knowledge to further optimize it.


Conference contributions | 2016

Detailed Reaction Schemes and Product Characterization Applied to Pyrolysis of a Single Spruce Particle

Andrés Anca-Couce, Peter Sommersacher, Robert Scharler, Christoph Hochenauer. Detailed Reaction Schemes and Product Characterization Applied to Pyrolysis of a Single Spruce Particle. 24rd European Biomass Conference & Exhibition (oral presentation).

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Peer Reviewed Scientific Journals | 2016

Dominating high temperature corrosion mechanism in low alloy steels in wood chips fired boilers

Gruber T, Retschitzegger S, Scharler R, Obernberger I. Dominating high temperature corrosion mechanism in low alloy steels in wood chips fired boilers. Energy and Fuels. 17 March 2016;30(3): 2385-2394.

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Ash related problems such as slagging, fouling, and high temperature corrosion in biomass fired boilers are still insufficiently explored due to the complexity of the underlying processes. High temperature corrosion of low alloy steels like 13CrMo4-5 has already been investigated in plants firing chemically untreated wood chips. In this earlier work it has been suggested that the oxidation of the steel is the dominating mechanism in the material temperature range between 450 and 550 °C. Unfortunately the exponential dependence of the material degradation on the flue gas temperature also found within this work cannot be explained with the proposed corrosion mechanism. To determine the dominating corrosion mechanism, additionally test runs have been carried out in a specially designed drop tube reactor. To investigate the time-dependent corrosion behavior of 13CrMo4-5, a newly developed mass loss probe was applied under several constant parameter setups. In addition to these measurements, the time-dependent oxidation of 13CrMo4-5 under air was investigated in a muffle furnace. To gain relevant information regarding the corrosion mechanism prevailing, the deposits as well as the corrosion products have been examined subsequently to the test runs by means of scanning electron microscopy and energy dispersive X-ray analyses. With the experimental data gained it could be shown that the dominating corrosion mechanism strongly depends on the conditions prevailing (e.g., steel temperature, flue gas temperature, and velocity) and can either be the oxidation of the steel by gaseous O2 and H2O or a combination of oxidation and active Cl-induced oxidation.


Other publication | 2016

Emission Reduction of Firewood Roomheaters by Optimization of Operating Conditions and Catalyst Integration

Reichert G, Stressler H, Schmidl C, Schwabl M, Sturmlechner R, Haslinger W. Emission Reduction of Firewood Roomheaters by Optimization of Operating Conditions and Catalyst Integration. 24th European Biomass Conference & Exhibition (oral presentation). June 2016, Amsterdam, Netherlands.

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Conference Papers | 2016

Energetische Verwertung einer Feinfraktion aus der MBA durch pyrolytische Behandlung

Meirhofer M, Wartha C, Strasser C. Energetische Verwertung einer Feinfraktion aus der MBA durch pyrolytische Behandlung. Recy & DepoTech 2016 (poster). November 2016, Leoben, Austria.

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Peer Reviewed Scientific Journals | 2016

Enhanced Separation of the Organic Fraction from Paper Mill Effluent for Energy Recovery

Stoyanova E, Bochmann G, Couperus A, Fuchs W. Enhanced Separation of the Organic Fraction from Paper Mill Effluent for Energy Recovery. Waste and Biomass Valorization. 1 October 2016;7(5): 1031-1039.

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Peer Reviewed Scientific Journals | 2016

Experimental investigations of hydrogen production from CO catalytic conversion of tar rich syngas by biomass gasification

Chianese S, Fail S, Binder M, Rauch R, Hofbauer H, Molino A, Blasi A, Musmarra D. Experimental investigations of hydrogen production from CO catalytic conversion of tar rich syngas by biomass gasification. Catalysis Today. 15 November 2016;277: 181-192.

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In this paper, the activity of a cobalt/molybdenum (Co/Mo) commercial catalyst for the Water Gas Shift Reaction for hydrogen production was investigated in a three fixed-bed reactor pilot plant using a tar-rich synthesis gas from a full-scale biomass gasification plant as feed-stream. A parametric variation study was carried out to assess CO conversion (XCO) and selectivity for the water gas shift reaction as a function of the operating temperature (T) in the range 300–450 °C. The effects of four dry gas hourly space velocities (GHSV), Case A-Case D, two steam to dry synthesis gas ratios (H2O/SG), 56% v/v and 67% v/v, and a H2S concentration in the range 100–220 ppmv,db were investigated: the highest CO conversion (∼95%) was observed in the base case (Case A GHSV) at 67% v/v H2O/SG, and 450 °C, the lower the operating temperature the lower the CO concentration, the lower the gas hourly space velocity the higher the CO conversion and the higher the H2O/SG the higher the CO conversion. The effect of H2S variation on CO conversion was also studied, keeping the operating temperature constant (≈365 °C) and using the Case D GHSV: CO conversion increased as the H2S concentration increased and XCO ≈ 40%. Selectivity was not influenced by the parameters investigated. Finally, the effect of the catalyst on tar removal was studied and a CO conversion close to 85% was found.


Conference Papers | 2016

Harmonised Greenhouse Gas Calculations for Electricity, Heating and Cooling from Biomass

Ludwiczek N, Bacovsky D, Sonnleitner A, Strasser C. Harmonised Greenhouse Gas Calculations for Electricity, Heating and Cooling from Biomass. e-nova 2016 (oral presentation). November 2016, Pinkafeld, Austria.

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Peer Reviewed Scientific Journals | 2016

Hydrogen production within a polygeneration concept based on dual fluidized bed biomass steam gasification

Kraussler M, Binder M, Schindler P, Hofbauer H. Hydrogen production within a polygeneration concept based on dual fluidized bed biomass steam gasification. Biomass and Bioenergy. 24 December 2016;

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Conference Papers | 2016

Hythane from biomass steam gasification as natural gas substitute in industrial applications

Kraussler M, Schindler P, Hofbauer H. Hythane from biomass steam gasification as natural gas substitute in industrial applications. Biorestec (poster). October 2016, Sitges, Spain.

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Technical Reports | 2016

IEA Bioenergy Countries´ Report

Bacovsky D, Dissauer C, Enigl M, Ludwiczek N, Pointner C, Sonnleitner A, Verma VK. IEA Bioenergy Countries´ Report. IEA Bioenergy Countries´ Report. August 2016.

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Peer Reviewed Scientific Journals | 2016

Impact of Na Promoter on Structural Properties and Catalytic Performance of CoNi/Al2O3 Nanocatalysts for the CO Hydrogenation Process: Fischer–Tropsch Technology

Nikparsa P, Mirzaei AA, Rauch R. Impact of Na Promoter on Structural Properties and Catalytic Performance of CoNi/Al2O3 Nanocatalysts for the CO Hydrogenation Process: Fischer–Tropsch Technology. Catalysis Letters. January 2016;146(1): 61-71.

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Conference Papers | 2016

Improving the propanol yield of mixed alcohol synthesis based on wood gas derived from biomass steam gasification

Binder M, Rauch R, Hofbauer H. Improving the propanol yield of mixed alcohol synthesis based on wood gas derived from biomass steam gasification. iSGA 2016 - 5th International Symposium on Gasification and its Applications (invited lecture). November/December 2016, Busan, Korea.

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Peer Reviewed Scientific Journals | 2016

Influence of firebed temperature on particle emissions in a residential wood pellet boiler

Gehrig M, Jäger D, Pelz SK, Weissinger A, Groll A, Thorwarth H, Haslinger W. Influence of firebed temperature on particle emissions in a residential wood pellet boiler. Atmospheric Environment. July 2016;136: 61-67.

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The crucial point in inorganic particle formation from biomass combustion is the temperature-dependent release of inorganic compounds, especially potassium (K). Currently, common wood fuels comprise of a comparatively low amount of K, but the increased usage of wood energy requires new feedstocks in the future. Potentially new feedstocks, such as short rotation coppice (SRC), fuels from agriculture (e.g., straw), or wood from broad-leafed trees of low rotation, contain usually high ash contents and/or high K concentrations. Apparently, these feedstocks will cause increased inorganic particle emissions from biomass combustion processes. The principle of a decreased firebed temperature as a primary measure aiming at a retention of K in the ashes of the firebed is a common approach for particle emission reduction and was investigated in several previous studies. The present study describes the usage of an ash-rich fuel from SRC pellets made from willow in a residential pellet boiler modified with an unique prototype of direct water-based firebed cooling. This test setup enables the study of the isolated impact of decreased firebed temperatures and its influence on the combustion process and emissions as well. A statistically significant effect of the firebed cooling on temperatures below the burner plate as on gaseous HCl and SO2 was found. The high ash content of the used fuel limited the effectiveness of the applied direct firebed cooling in residential biomass combustion. The accumulation of a thick and thermal insulating ash layer above the burner plate decreased the heat transfer, limited the cooling efficiency, and revealed deviations from the expected particle formation process.


Other publication | 2016

Influence of leak tightness and heat storage capacity of biomass room heating appliances on thermal efficiency

Sturmlechner R, Reichert G, Stressler H, Aigenbauer S, Schmidl C, Schwabl M, Haslinger W. Influence of leak tightness and heat storage capacity of biomass room heating appliances on thermal efficiency. 24th European Biomass Conference & Exhibition (poster). June 2016, Amsterdam, Netherlands.

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Peer Reviewed Scientific Journals | 2016

Investigation of real life operation of biomass room heating appliances – results of a European survey

Wöhler M, Andersen JS, Becker G, Persson H, Reichert G, Schön C, Schmidl C, Jaeger D, Pelz SK. Investigation of real life operation of biomass room heating appliances – results of a European survey. Applied Energy. 1 May 2016;169: 240-249.

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Peer Reviewed Scientific Journals | 2016

Investigation of User Behavior and Assessment of Typical Operation Mode for Different Types of Firewood Room Heating Appliances in Austria

Reichert G, Schmidl C, Haslinger W, Schwabl M, Moser W, Aigenbauer S, Wöhler M, Hochenauer C. Investigation of User Behavior and Assessment of Typical Operation Mode for Different Types of Firewood Room Heating Appliances in Austria. Renewable Energy. August 2016;93: 245-254.

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Firewood heaters like firewood roomheaters, tiled stoves and residential biomass cookers are commonly used for supplying the residences with renewable heat. However, these kinds of appliances were identified as responsible for relevant amounts of gaseous CO and OGC as well as particulate emissions causing negative health effects. Beside technological reasons, the operating conditions and the user behavior are essential reasons for increased emissions, especially in real life operation.

Therefore, this study aimed at an investigation and assessment of typical real life user behavior by a survey. Based on the findings effective and customer friendly technological and non-technological optimization approaches for a better and more environmental friendly real life performance were defined.

The results of the study showed principally similar user behavior of all considered types of appliances regarding most relevant operation characteristics, i.e. kind, properties and amount of used fuels, ignition procedure and air valve settings. Most effective non-technological optimization approaches were found for an enhancement of external training arrangements and the development of user friendly manuals that aimed mainly at an improvement of the ignition procedure from bottom–up to top–down ignition method. The use of devices with an automatically controlled combustion air supply was identified as promising technological measure.


Conference Papers | 2016

Investigations of a dual fluidized bed steam gasification plant by means of computation particle fluid dynamics

Kraft S, Kirnbauer F, Hofbauer H. Investigations of a dual fluidized bed steam gasification plant by means of computation particle fluid dynamics. 24th European Biomass Conference & Exhibition (oral presentation). June 2016, Amsterdam, Netherlands.

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Other Publications | 2016

Market integration of wood fuels and heating oil

Kristöfel C, Strasser C, Schmid E, Morawetz UB. Market integration of wood fuels and heating oil. 24th European Biomass Conference & Exhibition (poster). June 2016, Amsterdam, Netherlands.

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Conference contributions | 2016

Mathematische Modellierung mittlerer bis großer Solaranlagen als Basis für modellbasierte Regelungsstrategien

Unterberger V, Lichtenegger K, Innerhofer P, Gerardts B, Gölles M. Mathematische Modellierung mittlerer bis großer Solaranlagen als Basis für modellbasierte Regelungsstrategien. Gleisdorf Solar 2016. Gleisdorf: 2016. (Auszeichnung als innovativstes Poster).

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Peer Reviewed Scientific Journals | 2016

Mechanism of Layer Formation on Olivine Bed Particles in Industrial-Scale Dual Fluid Bed Gasification of Wood

Kuba M, He H, Kirnbauer F, Skoglund N, Boström D, Öhman M, Hofbauer H. Mechanism of Layer Formation on Olivine Bed Particles in Industrial-Scale Dual Fluid Bed Gasification of Wood. Energy & Fuels. 15 September 2016;30(9): 7410-7418.

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Utilization of biomass as feedstock in dual fluidized bed steam gasification is a promising technology for the substitution of fossil energy carriers. Experience from industrial scale power plants showed an alteration of the olivine bed material due to interaction with biomass ash components. This change results mainly in the formation of Ca-rich layers on the bed particles. In this paper, a mechanism for layer formation is proposed and compared to the better understood mechanism for layer formation on quartz bed particles. Olivine bed material was sampled at an industrial scale power plant before the start of operation and at pre-defined times after the operation had commenced. Therefore, time dependent layer formation in industrial-scale conditions could be investigated. The proposed mechanism suggests that the interaction between wood biomass ash and olivine bed particles is based on a solid-solid substitution reaction, where Ca2+ is incorporated into the crystal structure. As a consequence Fe2+/3+ and Mg2+ ions are expelled as oxides. This substitution results in the formation of cracks in the particle layer due to a volume expansion in the crystal structure once Ca2+ is incorporated. The results of this work are compared to relevant published results including those related to quartz bed particles.
 


Peer Reviewed Scientific Journals | 2016

Methodological approaches for fractionation and speciation to estimate trace element bioavailability in engineered anaerobic digestion ecosystems: An overview

van Hullebusch ED, Guibaud G, Simon S, Lenz M, Yekta SS, Fermoso FG, Jain R, Duester L, Roussel J, Guillon E, Skyllberg U, Almeida CMR, Pechaud Y, Garuti M, Frunzo L, Esposito G, Carliell-Marquet C, Ortner M, Collins G. Methodological approaches for fractionation and speciation to estimate trace element bioavailability in engineered anaerobic digestion ecosystems: An overview. Critical Reviews in Environmental Science and Technology. 17 August 2016;46(16): 1324-1366.

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Conference contributions | 2016

Mixed alcohol synthesis based on wood gas derived from dual fluidized bed biomass steam gasification - applying a rapeseed oil methyl ester gas scrubber for gas conditioning

Binder, M., Rauch, R., Hofbauer, H., 2016, "Mixed alcohol synthesis based on wood gas derived from dual fluidized bed biomass steam gasification - applying a rapeseed oil methyl ester gas scrubber for gas conditioning", poster presentation at BioResTec2016 - 1st International Conference on Bioresource Technology for Bioenergy, Bioproducts & Environmental Sustainability , 23 - 26 October 2016, Sitges, Spain.

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Peer Reviewed Scientific Journals | 2016

Modification of Co/Al2O3 Fischer–Tropsch Nanocatalysts by Adding Ni: A Kinetic Approach

Nikparsa P, Mirzaei AA, Rauch R. Modification of Co/Al2O3 Fischer–Tropsch Nanocatalysts by Adding Ni: A Kinetic Approach. International Journal of Chemical Kinetics. 1 March 2016;48(3): 131-142.

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Other Presentations | 2016

On site monitoring and dynamic simulation of a low energy house heated by a pellet boiler

Carlon E, Schwarz M, Prada A, Golicza L, Verma V, Baratieri M, Gasparella A, Haslinger W, Schmidl C. On site monitoring and dynamic simulation of a low energy house heated by a pellet boiler. 15 March 2016;116: 296-306.

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Prefabricated low energy houses are becoming increasingly popular thanks to their low cost and high energy performance. Heating systems installed in these houses should be optimally designed and controlled, to ensure thermal comfort for the whole heating season.

This study presents the on-site monitoring and dynamic simulation of a low energy house heated by a pellet boiler via a floor heating system. The house combines a lightweight envelope, a heat distribution system with a high thermal inertia and a biomass-based heat supply. The one-year monitoring campaign allowed to closely investigate the system's response to the heat demand. Moreover, a coupled simulation of the house and its heating and hot water supply system was set-up, calibrated, and validated against measured indoor temperature profiles and energy consumptions. Root mean square deviations between simulated and measured indoor temperature were in the range 0.4–0.8 K, while simulated energy consumptions fulfilled the criteria of the ASHRAE 14-2002 Guideline. As monitoring data evidenced the importance of better managing the high thermal inertia of the floor heating system, two improved control strategies were tested in the simulation environment and evaluated in terms of thermal comfort, pellet consumption and efficiency of the pellet boiler.


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