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Peer Reviewed Scientific Journals | 2021

A review on bed material particle layer formation and its positive influence on the performance of thermo-chemical biomass conversion in fluidized beds

Kuba M, Skoglund N, Öhman M, Hofbauer H. A review on bed material particle layer formation and its positive influence on the performance of thermo-chemical biomass conversion in fluidized beds.Fuel.2021.291:120214. https://doi.org/10.1016/j.fuel.2021.120214

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Bed material particle layer formation plays a significant role in thermo-chemical conversion of biomass. The interaction between biomass ash and bed material in fluidized bed conversion processes has been described for a variety of different applications and spans from fundamental research of formation mechanisms to effects of this layer formation on long-term operation in industrial-scale. This review describes the current state of the research regarding the mechanisms underlying layer formation and the positive influence of bed material particle layer formation on the operation of thermo-chemical conversion processes. Thus, the main focus lies on its effect on the catalytic activity towards gasification reactions and the impact on oxygen transport in chemical looping combustion. The review focuses on the most commonly investigated bed materials, such as quartz, feldspar or olivine. While the most relevant results for both the underlying mechanisms and the subsequently observed effects on the operation are presented and discussed, knowledge gaps where further research is necessary are identified and described.


Peer Reviewed Scientific Journals | 2021

Advanced Optimal Planning for Microgrid Technologies including Hydrogen and Mobility at a real Microgrid Testbed

Mansoor M, Stadler M, Auer H, Zellinger M. Advanced Optimal Planning for Microgrid Technologies including Hydrogen and Mobility at a real Microgrid Testbed. International Journal of Hydrogen Energy.2021.

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This paper investigates the optimal planning of microgrids including the hydrogen energy system through mixed-integer linear programming model. A real case study is analyzed by extending the only microgrid lab facility in Austria. The case study considers the hydrogen production via electrolysis, seasonal storage and fueling station for meeting the hydrogen fuel demand of fuel cell vehicles, busses and trucks. The optimization is performed relative to two different reference cases which satisfy the mobility demand by diesel fuel and utility electricity based hydrogen fuel production respectively. The key results indicate that the low emission hydrogen mobility framework is achieved by high share of renewable energy sources and seasonal hydrogen storage in the microgrid. The investment optimization scenarios provide at least 66% and at most 99% carbon emission savings at increased costs of 30% and 100% respectively relative to the costs of the diesel reference case (current situation).


Other publication | 2021

Algae4Fish - Video

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Peer Reviewed Scientific Journals | 2021

An adaptive short-term forecasting method for the energy yield of flat-plate solar collector systems

Unterberger V, Lichtenegger K, Kaisermayer V, Gölles M, Horn M. An adaptive short-term forecasting method for the energy yield of flat-plate solar collector systems. Applied Energy. 2021 Apr 16;2021(293). https://doi.org/10.1016/j.apenergy.2021.116891

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The number of large-scale solar thermal installations has increased rapidly in Europe in recent years, with 70 % of these systems operating with flat-plate solar collectors. Since these systems cannot be easily switched on and off but directly depend on the solar radiation, they have to be combined with other technologies or integrated in large energy systems. In order to most efficiently integrate and operate solar systems, it is of great importance to consider their expected energy yield to better schedule heat production, storage and distribution. To do so the availability of accurate forecasting methods for the future solar energy yield are essential. Currently available forecasting methods do not meet three important practical requirements: simple implementation, automatic adaption to seasonal changes and wide applicability. For these reasons, a simple and adaptive forecasting method is presented in this paper, which allows to accurately forecast the solar heat production of flat-plate collector systems considering weather forecasts. The method is based on a modified collector efficiency model where the parameters are continuously redetermined to specifically consider the influence of the time of the day. In order to show the wide applicability the method is extensively tested with measurement data of various flat-plate collector systems covering different applications (below 200 Celsius), sizes and orientations. The results show that the method can forecast the solar yield very accurately with a Mean Absolute Range Normalized Error (MARNE) of about 5 % using real weather forecasts as inputs and outperforms common forecasting methods by being nearly twice as accurate.


Peer Reviewed Scientific Journals | 2021

Analysing price cointegration of sawmill by-products in the forest-based sector in Austria

Fuhrmann M, Dißauer C, Strasser C, Schmid E. Analysing price cointegration of sawmill by-products in the forest-based sector in Austria. Forest Policy and Economics. 2021.131:102560.

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Empirical analyses of interlinkages and price dependencies in the forest-based sector support the forecast of market developments and the design of efficient utilization pathways. This article aims at analysing price cointegration between roundwood (sawlogs, pulpwood), sawmill by-products (sawdust, wood chips) and wood products (pellets, particle board) in the forest-based sector in Austria. Monthly price data for the period 2005–2019 were used for the following statistical tests: (1) The Augmented-Dickey-Fuller and Zivot-Andrews unit root tests were conducted to investigate stationarity of the data; (2) The Johansen Cointegration test was pairwise applied to price time series; (3) The Granger Causality test was used for cointegrated time series to examine which one is price leading. Furthermore, sawmill by-product prices were modelled as Vector Error Correction Models (VECM) to analyse their common behaviour. The dataset was divided to a training (2005–2017) and test (2018–2019) subset to assess the prediction accuracy of the models. The training data were used to estimate a VAR model as basis for forecasts, which were compared to the test data. Results show that sawdust prices are cointegrated and thus modelled with pellet and particle board prices. In contrast, wood chips are used for several applications and thus prices are cointegrated and modelled with prices of sawlogs, pulpwood, pellets and particle board. The comparison with the test data showed that forecasts were able to predict data from 2018 to 2019 well. However, a decrease in prices, starting in 2019 and intensified by the Covid-19 pandemic, could not be fully captured by these forecasts.


Peer Reviewed Scientific Journals | 2021

Analysis of H2S-related short-term degradation and regeneration of anode- and electrolyte supported solid oxide fuel cells fueled with biomass steam gasifier product gas

Pongratz G, Subotić V, Schroettner H, Hochenauer C, Skrzypkiewicz M, Kupecki J, Anca-Couce A, Scharler R. Analysis of H2S-related short-term degradation and regeneration of anode- and electrolyte supported solid oxide fuel cells fueled with biomass steam gasifier product gas. Energy.2021.218:119556.

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Using solid oxide fuel cells in biomass gasification based combined heat and power production is a promising option to increase electrical efficiency of the system. For an economically viable design of gas cleaning units, fuel cell modules and further development of suitable degradation detection methods, information about the behavior of commercially available cell designs during short-term poisoning with H2S can be crucial. This work presents short-term degradation and regeneration analyses of industrial-relevant cell designs with different anode structure and sulfur tolerance fueled with synthetic product gas from wood steam gasification containing 1 to 10 ppmv of H2S at 750°C and 800°C. Full performance regeneration of both cell types was achieved in all operating points. The high H2O content and avoided fuel depletion may have contributed to a lower performance degradation and better regeneration of the cells. A strong influence of the catalytically active anode volume on poisoning and regeneration behavior was quantified, thereby outlining the importance of considering the anode structure besides the sulfur tolerance of the anode material. Hence, cells with less sulfur tolerant anode material but larger anode volume might outperform cells less sensitive to sulfur in the case of an early detection of a gas cleaning malfunction.


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.


Other Presentations | 2021

Betrieb verbundener Nahwärmenetze mit getrennten Eigentümern

Zemann C, Muschick D, Kaisermayer V, Gölles M. Betrieb verbundener Nahwärmenetze mit getrennten Eigentümern. QM Heizwerke Fachtagung, Bad Vöslau, 14. Oktober, 2021. (oral presentation)

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Warum ist es sinnvoll, Wärmenetze zu verbinden?

  • Erläuterung am Beispiel des Projekts Thermaflex
  • Drei Wärmenetze bei Leibnitz in der Steiermark.
  • Sind gewachsen und haben die Grenzen ihrer Nachbar-Wärmenetze erreicht.
  • Die Wärmenetze werden durch zwei getrennte Eigentümer betrieben.

Peer Reviewed Scientific Journals | 2021

Bioenergy technologies, uses, market and future trends with Austria as a case study

Anca-Couce A, Hochenauer C, Scharler R. Bioenergy technologies, uses, market and future trends with Austria as a case study. Renewable and Sustainable Energy Reviews.2021;135:110237.

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The current bioenergy uses and conversion technologies as well as future trends for the production of heat, power, fuels and chemicals from biomass are reviewed. The focus is placed in Austria, which is selected due to its high bioenergy utilization, providing 18.4% of the gross energy final consumption in 2017, and its strong industrial and scientific position in the field. The most common bioenergy application in Austria is bioheat with 170 PJ in 2017 mainly obtained from woody biomass combustion, followed by biofuels with 21 PJ and bioelectricity with 17 PJ. Bioheat has a stable market, where Austrian manufacturers of boilers and stoves have a strong position exporting most of their production. Future developments in bioheat production should go in the line of further reducing emissions, increasing feedstock flexibility and coupling with other renewables. For bioelectricity and biofuels, the current framework does not promote the growth of the current main technologies, i.e. combined heat and power (CHP) based on biomass combustion or biogas and first generation biofuels. However, an increase in all bioenergy uses is required to achieve the Austrian plan to be climate neutral in 2040. The current initiatives and future possibilities to achieve this increase are presented and discussed, e.g. mandatory substitution of old oil boilers, production of biomethane and early commercialization of CHP with a high efficiency or demonstration of advanced biofuels production based on gasification.


Peer Reviewed Scientific Journals | 2021

Categorization of small-scale biomass combustion appliances by characteristic numbers

Feldmeier S, Schwarz M, Wopienka E, Pfeifer C. Categorization of small-scale biomass combustion appliances by characteristic numbers. Renewable Energy. 2021.163:2128-2136.

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The market offers a broad range of different combustion appliances dedicated to residential heating with biomass. The effect of fuel properties on the formation of slag and emissions varies and the technology influences the impact to a certain extent. The applicability of biomass fuels is not only determined by operational settings but also by the design of boiler components as grate area and combustion chamber. Aspects as the fuel load on the grate, residence time, geometry of grate and combustion chamber design, as well as feeding and de-ashing influence the extent of slag formation and emission release. The determination of characteristic numbers by means of constructional measures allows a systematic comparison and - in a further step - an assessment/categorization of combustion technologies. After conducting a boiler survey relevant parameters regarding grate, combustion chamber, feeding, and ash removal were gathered. Characteristic numbers were specified in order to compare technological aspects. The results of this study allow the investigation of the influence of the combustion technology on the performance. They will assist the systematic and targeted design of small-scale boilers and the optimization of combustion appliances in future, especially when it comes to fuel-flexibility.


Peer Reviewed Scientific Journals | 2021

Combustion of poultry litter and mixture of poultry litter with woodchips in a fixed bed lab-scale batch reactor

Katsaros G, Sommersacher P, Retschitzegger S, Kienzl N, Tassou SA, Pandey DS. Combustion of poultry litter and mixture of poultry litter with woodchips in a fixed bed lab-scale batch reactor. Fuel. 2021.286.119310.

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Experiments have been conducted in a batch fixed bed lab-scale reactor to investigate the combustion behaviour of three different biomass fuels, poultry litter (PL), blend of PL with wood chips (PL/WC) and softwood pellets (SP). Analysis of the data gathered after completion of the test runs, provided useful insights about the thermal decomposition behaviour of the fuels, the formation of N gaseous species, the release of ash forming elements and the estimation of aerosol emissions. It was observed that the N gaseous species are mainly produced during the devolatilisation phase. Hydrogen cyanide (HCN) was the predominant compound in the case of SP combustion, whereas ammonia (NH3) displayed the highest concentration during the combustion of PL and blend (PL/WC). With reference to ash forming elements, the release rates of potassium (K) and sodium (Na) range between 15–50% and 20–37% respectively, whereas the release rate of sulphur (S) falls between 54–92%. Chlorine (Cl) presents very high release rate for all tested fuels acquiring values greater than 85%, showing the volatile nature of the specific compound. The maximum potential of aerosol emissions was estimated based on the calculation of ash forming elements. In particular, during PL combustion the maximum aerosol emissions were observed, 2806 mg/Nm3 (dry flue gas, 13 vol% O2), mainly influenced by the release rate of K in the gas phase. Fuel indexes for the pre-evaluation of combustion related challenges such as NOx emissions, potential for aerosols formation, corrosion risk, and ash melting behaviour have also been investigated.


Technical Reports | 2021

Control of DHC networks and Reduction of the operating temperatures in DH systems

Task 55 Towards the Integration of Large SHC Systems into DHC Networks

Gölles M, Muschick D, Unterberger V, Leoni P, Schmidt R, Lennermo G. "Control of DHC networks and Reduction of the operating temperatures in DH systems". EA SHC FACTSHEET 55.A-D4.2. Date of Publication: 28.01.2021. https://task55.iea-shc.org/fact-sheets

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Overview on different approaches for the control of the heat distribution networks in case of the integration of large-scale solar thermal systems, and different possibilities for the reduction of the operating temperatures in DH systems.


Technical Reports | 2021

Control of large-scale solar thermal plants

Task 55 Towards the Integration of Large SHC Systems into DHC Networks

Gölles M, Unterberger V. "Control of large-scale solar thermal plants". IEA SHC FACTSHEET 55.B-D3.1. Date of Publication: 28.01.2021. https://task55.iea-shc.org/fact-sheets

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Overview on the control of large-scale thermal plants, limited to plants feeding into DH networks as well as theirkey components, i.e. the actual collector circuit and the heat exchanger between primary and secondary circuit.


Peer Reviewed Scientific Journals | 2021

Correlations between tar content and permanent gases as well as reactor temperature in a lab-scale fluidized bed biomass gasifier applying different feedstock and operating conditions

von Berg L, Pongratz G, Pilatov A, Almuina-Villar H, Scharler R, Anca-Couce A. Correlations between tar content and permanent gases as well as reactor temperature in a lab-scale fluidized bed biomass gasifier applying different feedstock and operating conditions.Fuel.2021.305:121531

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The major problem of fluidized bed biomass gasification is the high tar contamination of the producer gas which is associated with the complex and time-consuming sampling and analysis of these tars. Therefore, correlations to predict the tar content are a helpful tool for the development and operation of biomass gasifiers. Correlations between tars and gas composition as well as reactor temperature derived for a steam-blown lab-scale bubbling fluidized bed gasifier are investigated in this study to assess their applicability. A comprehensive data set containing over 80 experimental points was obtained for various operation conditions, including variations in temperature from 700 to 800 °C, feedstock, amount of steam for fluidization, as well as the addition of oxygen. Linear correlations between tar and permanent gases show good accuracy for H2 and CH4 when using pure steam. However, experiments conducted with steam-oxygen mixtures show high deviations for the CH4-based correlation and smaller but still significant deviations for the H2-based correlation. No relation between tar and CO or CO2 was found. The correlation between tar and temperature shows highest accuracy, including good agreement with the steam-oxygen experiments. All tar correlations showed useful results over a broad operating range. However, significant deviations can be obtained when considering just one gas compound. Therefore, a combination of different correlations considering gas components and temperature seems to be the best method of tar prediction. This leads to a powerful tool for fast online tar monitoring for a broad range of operating conditions, once a calibration measurement was conducted.


Peer Reviewed Scientific Journals | 2021

Dekarbonisierung in Salzburgs Skigebieten – Entwicklung von Optimierungsalgorithmen und Energiemanagementsystemen zur Steigerung der Energieeffizienz, Minimierung von Emissionen und Optimierung von Flexibilitäten [Decarbonization of the skiing areas in

Kritzer S, Passegger H, Ayoub T, Liedtke P, Zellinger M, Stadler M, Iglar B, Korner C, Aghaie H. Dekarbonisierung in Salzburgs Skigebieten – Entwicklung von Optimierungsalgorithmen und Energiemanagementsystemen zur Steigerung der Energieeffizienz, Minimierung von Emissionen und Optimierung von Flexibilitäten [Decarbonization of the skiing areas in Salzburg – development of optimization algorithms and energy management systems to increase energy efficiency, minimize emissions and optimize flexibility]. Elektrotechnik und Informationstechnik. 31 May 2021.

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Winter tourism is an energy-intensive branch of industry. The aim of the FFG funding project Clean Energy for Tourism is to support Salzburg’s skiing areas on the way to decarbonization by developing technologies and business models. In this article, the developed ICT infrastructure, the optimization algorithms and the business models are presented.


Peer Reviewed Scientific Journals | 2021

Detailed NOX precursor measurements within the reduction zone of a novel small-scale fuel flexible biomass combustion technology

Archan G, Scharler R, Pölzer L, Buchmayr M, Sommersacher P, Hochenauer C, Gruber J, Anca-Couce A. Detailed NOX precursor measurements within the reduction zone of a novel small-scale fuel flexible biomass combustion technology. Fuel. 15 October 2021.302:121073

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A novel biomass combustion technology with a compact fixed-bed operated with a low oxygen content and double air staging was investigated. Minimized flue gas emissions at high fuel flexibility were achieved only with primary measures. The fuel nitrogen conversion mechanisms were investigated in detail in the secondary zone of a 30 kW lab-reactor, designed as efficient reduction zone. Experimental investigations were carried out to determine the distribution of gas temperatures, main dry product gas components as well as NOX precursors such as NH3 and HCN along the height of the reduction zone. The objective was to determine and understand the various fuel nitrogen conversion mechanisms in the reduction zone that can minimize NOX emissions.

It was found that the HCN/NH3 ratio increases with the fuel nitrogen content. This corresponds to an unexpected opposite trend to typical biomass grate furnaces. It was concluded that it is crucial for the HCN/NH3 ratio whether the released nitrogen tars are already cracked in the fixed-bed or only in the gas phase, as in the novel technology. Furthermore, the influence of gas temperature, air ratio, mixing, recirculated flue gas and residence time on the formation and reduction of NH3, HCN and NO is discussed.

Finally, this novel technology achieves NOX emissions of<95 mg·m−3 and 175 mg·m−3 for woody and herbaceous fuels, respectively, which is well below the small-scale state-of-the-art for the respective N contents and it achieves fuel nitrogen conversions to NOX in flue gas of 35% and 25%, respectively.


Peer Reviewed Scientific Journals | 2021

Digestate as Sustainable Nutrient Source for Microalgae—Challenges and Prospects

Bauer L, Ranglová K, Masojidek J, Drosg B, Meixner K. Digestate as Sustainable Nutrient Source for Microalgae—Challenges and Prospects. Applied Sciences. 2021.11(3):1056

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The interest in microalgae products has been increasing, and therefore the cultivation industry is growing steadily. To reduce the environmental impact and production costs arising from nutrients, research needs to find alternatives to the currently used artificial nutrients. Microalgae cultivation in anaerobic effluents (more specifically, digestate) represents a promising strategy for increasing sustainability and obtaining valuable products. However, digestate must be processed prior to its use as nutrient source. Depending on its composition, different methods are suitable for removing solids (e.g., centrifugation) and adjusting nutrient concentrations and ratios (e.g., dilution, ammonia stripping). Moreover, the resulting cultivation medium must be light-permeable. Various studies show that growth rates comparable to those in artificial media can be achieved when proper digestate treatment is used. The necessary steps for obtaining a suitable cultivation medium also depend on the microalgae species to be cultivated. Concerning the application of the biomass, legal aspects and impurities originating from digestate must be considered. Furthermore, microalgae species and their application fields are essential criteria when selecting downstream processing methods (harvest, disintegration, dehydration, product purification). Microalgae grown on digestate can be used to produce various products (e.g., bioenergy, animal feed, bioplastics, and biofertilizers). This review gives insight into the origin and composition of digestate, processing options to meet requirements for microalgae cultivation and challenges regarding downstream processing and products.


Peer Reviewed Scientific Journals | 2021

Drivers and barriers in retrofitting pulp and paper industry with bioenergy for more efficient production of liquid, solid and gaseous biofuels: A review.

Mäki E, Saastamoinen H, Melin K, Matschegg D, Pihkola H. Drivers and barriers in retrofitting pulp and paper industry with bioenergy for more efficient production of liquid, solid and gaseous biofuels: A review. Biomass and Bioenergy. 2021.106036. https://doi.org/10.1016/j.biombioe.2021.106036

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Ample interest for more efficient utilization of bio-based residues has emerged in the Nordic pulp and paper (P&P) industry, which uses virgin wood as feedstock. Although different bioenergy retrofit technologies for production of liquid, solid, and gaseous bioenergy products have been applied in the existing P&P mills, the number of installations remains small. The lack of profound knowledge of existing bioenergy retrofits hinders the replication and market uptake of potential technologies. This review synthesises the existing knowledge of European installations and identifies the key drivers and barriers for implementation to foster the market uptake of potential technologies. The bioenergy retrofits were reviewed in terms of technical maturity, drivers, barriers and market potential. Based on this evaluation, common drivers and barriers towards wider market uptake were outlined from political, economic, social, technical, environmental, and legal perspective. Technologies already commercially applied include anaerobic fermentation of sludge, bark gasification, tall oil diesel and bioethanol production, whereas lignin extraction, biomethanol production, hydrothermal liquefaction and hydrothermal carbonization are being demonstrated or first applications are under construction. The findings of this review show that a stable flow of residues at P&P mills creates a solid base for retrofitting. New innovative bio-based products would allow widening the companies' product portfolios and creating new businesses. Also, European Union's (EU) legislation drives towards advanced biofuels production. Wider uptake of the retrofitting technologies requires overcoming the barriers related to uncertainty of economic feasibility and unestablished markets for new products rather than technical immaturity. 


Peer Reviewed Scientific Journals | 2021

Effect of biomass fuel ash and bed material on the product gas composition in DFB steam gasification

Fürsatz K, Fuchs J, Benedikt F, Kuba M, Hofbauer H. Effect of biomass fuel ash and bed material on the product gas composition in DFB steam gasification. Energy. 2021.219:119650.

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Gasification is a thermochemical process that transforms carbonaceous matter into a gaseous secondary energy carrier, referred to as product gas. This product gas can be used for heat and power generation but also for syntheses. One possible gasification technology suitable for further synthesis is dual fluidised bed (DFB) steam gasification. The H2:CO ratio, which determines the suitability of the product gas for further synthesis, is influenced by the catalytic activity inside the gasification reactor. Eleven DFB steam gasification experiments were performed comparing the catalytic activity for various bed material and fuel combinations. The bed materials used were K-feldspar, fresh and layered olivine, and limestone, and the fuels gasified were softwood, chicken manure, a bark–chicken manure mixture and a bark-straw-chicken manure mixture. The water-gas-shift (WGS) equilibrium deviation was used to evaluate the catalytic activity inside the gasification reactor. It was shown that both the fuel ash and bed material have an effect on the catalytic activity during gasification. Scanning electron microscopy and energy dispersive X-ray spectrometry showed the initial layer formation for experiments with ash-rich fuels. Isolated WGS experiments were performed to further highlight the influence of bed material, fuel ash and fuel ash layers on the WGS equilibrium.


Peer Reviewed Scientific Journals | 2021

Emission minimization of a top-lit updraft gasifier cookstove based on experiments and detailed CFD analyses

Scharler R, Archan G, Rakos C, von Berg L, Lello D, Hochenauer C, Anca-Couce A. Emission minimization of a top-lit updraft gasifier cookstove based on experiments and detailed CFD analyses. Energy Conversion and Management. 2021.247:114755.

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Around 2.7 billion people worldwide have no access to clean cooking equipment, which leads to major health problems due to high emissions of unburned products (VOC, CO and soot). A top-lit updraft gasifier cookstove with forced draft was identified as the technology with the highest potential for reducing harmful emissions from incomplete combustion in simple cookstoves. The basic variant of the stove was equipped with a fan for efficient mixing of product gas with air and fired with pellets to increase the energy density of low-grade residues. The development was conducted based on water boiling test experiments for wood and rice hull pellets and targeted CFD simulations of flow, heat transfer and gas phase combustion with a comprehensive description of the reaction kinetics, which were validated by the experiments. Emphasis was put on the reduction of CO emissions as an indicator for the burnout quality of the flue gas. The optimisation was carried out in several steps, the main improvements being the design of a sufficiently large post-combustion chamber and a supply of an appropriate amount of primary air for a more stable fuel gasification. The experiments showed CO emissions <0.2 g/MJdel for wood and rice hull pellets, which corresponds to a reduction by a factor of about 15 to 20 compared to the basic forced draft stove concept. Furthermore, these values are between 5 and 10 times lower than published water boiling test results of the best available cookstove technologies and are already close to the range of automatic pellet furnaces for domestic heating, which are considered to be the benchmark for the best possible reduction of CO emissions.


Technical Reports | 2021

Endbericht: Heat Pumping system Control (HPC)

Modellbasierte Regelung von Absorptionswärmepump-Anlagen.

Zlabinger S, Wernhart M, Unterberger V, Rieberer R, Gölles M, Rohringer C, Poier H, Halmdienst C, Kemmerzehl C, Otto M. Heat Pumping system Control (HPC). Modellbasierte Regelung von Absorptionswärmepump-Anlagen. FFG, 4. Ausschreibung Energieforschungsprogramm, Projektnummer: 865095. Endbericht. 2021.

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Studien | 2021

Energiespeicher in Österreich

Marktentwicklung 2020

Biermayr P, Aigenbauer St, Enigl M, Fink C, Knabl S, Leonhartsberger K, Matschegg D, Prem E, Strasser C, Wittmann M. Energiespeicher in Österreich Marktentwicklung 2020. 2021

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Peer Reviewed Scientific Journals | 2021

Experimental evaluation of primary measures for NOX and dust emission reduction in a novel 200 kW multi-fuel biomass boiler

Archan G, Anca-Couce A, Buchmayr M, Hochenauer C, Gruber J, Scharler R. Experimental evaluation of primary measures for NOX and dust emission reduction in a novel 200 kW multi-fuel biomass boiler. June 2021.170:1186-1196. https://doi.org/10.1016/j.renene.2021.02.055

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The aim of this work is to utilize various biogenic fuels without ash slagging and to significantly reduce NOX and particulate matter emissions in comparison to modern combustion technologies. For this purpose, a novel small-scale multi-fuel biomass grate furnace technology was developed and experimentally investigated. It employs a low oxygen concentration in the fixed-bed and a double air staging, including the supply of flue gas recirculation. In this way slagging is prevented on the grate, reducing the release of ash-forming volatiles, NOX emissions are minimized in the reduction zone and an efficient flue gas burnout is achieved in the tertiary zone. Wood pellets and chips as well as miscanthus briquettes were investigated.

The measured total particle emissions showed a reduction of 68% for pellets and 70% for wood chips compared to typical small-scale furnaces. Furthermore, a reduction of NOX emissions of 39% for wood chips, 40% for wood pellets and 45% for miscanthus briquettes was achieved compared to typical small-scale furnaces. The experimental parameter study provided fundamental insights into the various mechanisms involved in this novel technology, which is close to market introduction, and proved its high fuel flexibility and great potential for particulate matter and NOX emission reduction.


Peer Reviewed Scientific Journals | 2021

Fischer-Tropsch products from biomass-derived syngas and renewable hydrogen

Gruber H, Groß P, Rauch R, Reichhold A, Zweiler R, Aichernig C, Müller S, Ataimisch N, Hofbauer H. Fischer-Tropsch products from biomass-derived syngas and renewable hydrogen. Biomass Conversion and Biorefinery. 2021.11(6):2281-2292

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Global climate change will make it necessary to transform transportation and mobility away from what we know now towards a sustainable, flexible, and dynamic sector. A severe reduction of fossil-based CO2 emissions in all energy-consuming sectors will be necessary to keep global warming below 2 °C above preindustrial levels. Thus, long-distance transportation will have to increase the share of renewable fuel consumed until alternative powertrains are ready to step in. Additionally, it is predicted that the share of renewables in the power generation sector grows worldwide. Thus, the need to store the excess electricity produced by fluctuating renewable sources is going to grow alike. The “Winddiesel” technology enables the integrative use of excess electricity combined with biomass-based fuel production. Surplus electricity can be converted to H2 via electrolysis in a first step. The fluctuating H2 source is combined with biomass-derived CO-rich syngas from gasification of lignocellulosic feedstock. Fischer-Tropsch synthesis converts the syngas to renewable hydrocarbons. This research article summarizes the experiments performed and presents new insights regarding the effects of load changes on the Fischer-Tropsch synthesis. Long-term campaigns were carried out, and performance-indicating parameters such as per-pass CO conversion, product distribution, and productivity were evaluated. The experiments showed that integrating renewable H2 into a biomass-to-liquid Fischer-Tropsch concept could increase the productivity while product distribution remains almost the same. Furthermore, the economic assessment performed indicates good preconditions towards commercialization of the proposed system.


Other publication | 2021

Gemeinsam richtig heizen - Video

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