Sortierung Titel Year

Publikationen


Conference Papers | 2020

Advanced modular process analysis tool for biomass-based Chemical Looping systems

Steiner T, Schulze K, Scharler R. Advanced modular process analysis tool for biomass-based Chemical Looping systems. 3RD DOCTORAL COLLOQUIUM BIOENERGY. 2020.

External Link

Details

In order to limit global warming to 1.5 °C compared to the pre-industrial temperature level, zero net CO2 emissions are needed on a global scale until 2050. A Chemical Looping (CL) process represents a technological system which is CO2-negative when using biomass as fuel and thus can substantially contribute to this target. In principle, the process uses a metal oxide as oxygen carrier material (OC) which is cyclically oxidized by air or steam and reduced by the fuel. Without air as the direct oxygen source for fuel conversion, high calorific product gases or pure carbon dioxide in case of combustion are obtained after the condensation of water vapor, which can then be stored or further utilized.
Within the funded project ”BIO-LOOP”, different Chemical Looping processes (for example combustion, gasification, hydrogen production) and reactors (fixed bed, fluidized bed) are investigated numerically and experimentally. An advanced process analysis tool based on mass and energy balances of the system considered will be presented. It provides data about the specific internal and external streams, process conditions and efficiencies. Within the analysis tool, various independent modular units describe individual process steps, e.g. mixing, chemical reaction or splitting. These components can be adjusted, combined and interconnected according to the flow chart of the system. The process model represents the first step towards a flexible Chemical Looping reactor simulation toolbox to analyze various process scenarios. Emphasis is put on the flexibility regarding the fuels and oxygen carriers, their conversion and possible process variations. The tool developed will support upcoming CFD modeling and further economic considerations.


Conference contributions | 2020

Advanced Test Methods for Pellet Stoves

Reichert G, Schmidl C. Advanced Test Methods for Pellet Stoves. 6th Central European Biomass Conference, 2020, Graz.

Download PDF

Details


Conference contributions | 2020

Advanced Test Methods for Pellet Stoves – A Technical Review

Reichert G, Schwabl M, Schmidl C. Advanced Test Methods for Pellet Stoves – A Technical Review. 6th Central European Biomass Conference (oral presentation) 2020.

External Link

Download PDF

Details

Third party testing of direct heating appliances fueled with pellets has been established in many countries worldwide. The main goals are ensuring operation safety and a minimum level of performance of the products prior to market implementation. This kind of approval procedure for new products requires testing standards, certified testing bodies and a legal framework defining minimum requirements for specified performance parameters which are assessed in the respective standards.

While the overall targets are quite similar for all countries having set-up such procedures, the practical implementation of these targets in the national/international testing standards is remarkably different. This applies to both, the way of operating the appliance during the testing and the measurements performed during the testing.

Furthermore several industries were requested recently to modify their product standards towards more realistic operating conditions. The most famous example is car industry, but this request may also apply to biomass heating systems.

 


Peer Reviewed Scientific Journals | 2020

Alkaline Ethanol Oxidation Reaction on Carbon Supported Ternary PdNiBi Nanocatalyst using Modified Instant Reduction Synthesis Method

Cermenek B, Genorio B, Winter T, Wolf S, Connell JG, Roschger M, Letofsky-Papst I, Kienzl N, Bitschnau B, Hacker V. Alkaline Ethanol Oxidation Reaction on Carbon Supported Ternary PdNiBi Nanocatalyst using Modified Instant Reduction Synthesis Method. Electrocatalysis. 2020.11:203-204.

External Link

Details

Direct ethanol fuel cells (DEFC) still lack active and efficient electrocatalysts for the alkaline ethanol oxidation reaction (EOR). In this work, a new instant reduction synthesis method was developed to prepare carbon supported ternary PdNiBi nanocatalysts with improved EOR activity. Synthesized catalysts were characterized with a variety of structural and compositional analysis techniques in order to correlate their morphology and surface chemistry with electrochemical performance. The modified instant reduction synthesis results in well-dispersed, spherical Pd85Ni10Bi5 nanoparticles on Vulcan XC72R support (Pd85Ni10Bi5/C(II-III)), with sizes ranging from 3.7 ± 0.8 to 4.7 ± 0.7 nm. On the other hand, the common instant reduction synthesis method leads to significantly agglomerated nanoparticles (Pd85Ni10Bi5/C(I)). EOR activity and stability of these three different carbon supported PdNiBi anode catalysts with a nominal atomic ratio of 85:10:5 were probed via cyclic voltammetry and chronoamperometry using the rotating disk electrode method. Pd85Ni10Bi5/C(II) showed the highest electrocatalytic activity (150 mA⋅cm−2; 2678 mA⋅mg−1) with low onset potential (0.207 V) for EOR in alkaline medium, as compared to a commercial Pd/C and to the other synthesized ternary nanocatalysts Pd85Ni10Bi5/C(I) and Pd85Ni10Bi5/C(III). This new synthesis approach provides a new avenue to developing efficient, carbon supported ternary nanocatalysts for future energy conversion devices.


Conference contributions | 2020

Anaerobic Digestion Optimization for Biogas and Biomethane Production

Ionel I, Drosg B. Anaerobic Digestion Optimization for Biogas and Biomethane Production. 28th European Biomass Conference and Exhibition (oral presentation) 2020.

Details


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.

External Link

Details

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.


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.

External Link

Details

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 | 2020

BIOCHAR - Reaction kinetics under gasification conditions by experimental tests with TGA

Lagler J, Martini S, Kienzl N, Loder A. BIOCHAR - Reaction kinetics under gasification conditions by experimental tests with TGA. 6th Central European Biomass Conference. 2020. Graz.

Download PDF

Details


Conference contributions | 2020

Biochar’s reaction kinetics under gasification conditions by experimental tests with TGA

Lagler J, Martini S, Kienzl N, Loder A. Biochar’s reaction kinetics under gasification conditions by experimental tests with TGA. 6th Central European Biomass Conference (poster). 2020.

External Link

Download PDF

Details

During the last years biomass evolved into one of the most important energy sources in Central Europe. Depending on the atmosphere, different types of thermochemical processes can be differentiated: pyrolysis, gasification and combustion, whereas pyrolysis operates without any oxygen in the atmosphere, combustion with the highest ratio of oxygen. Depending on the conversion technology and conversion conditions, different products can be generated: heat, cooling power and electrical power, liquid, gaseous and solid products, such as hydrogen, FT-fuels and biochar.
This work focuses on the valorisation of solid side products of gasification based biomass CHP-systems to increase ecologic and economic benefit. Depending on the conversion process of biomass into producer gas this solid residue consists mainly of ash or of so called biochar with high carbon content. Increasing the amount of biochar leads to a decrease of producer gas, but, with the high market potential of biochar, the economic benefits increase. According to its characteristics (e.g. purity, surface structure) different applications can be addressed and therefore different prices can be achieved. Therefore, extended research on biochar treatment processes and related reaction kinetics of biochar is from crucial importance for the development and optimisation of downstream upgrading processes in order to reach the desired quality of the biochar. In the past, such considerations of utilising side products, like biochar, have not been in the centre of attention during the design phase of gasification reactors. Therefore, the establishment of a finishing-treatment of biochar extracted from a gasification process is under investigation. The focus of this paper lies on the reaction kinetics of biochar activation itself and not the primary material (biomass). In order to derivate correlations between reaction kinetics and atmosphere compositions as well as temperature, experimental test runs are conducted with a Thermogravimetric Analyser (TGA) including a steam furnace, which enables studies of mass and energy changes under defined absolute humidity. To produce applicable and reliable data, the limitations of the TGA-test-setup are evaluated with examinations on variations of sample mass, bulk density, particle size distribution and the gas flow. On this basis the test design is defined with certain specifications on the sample preparation and a constant flow velocity. The investigated biochar taken out the gasification process is dried, milled and sieved for the TGA-tests. The main part is devoted to conduct a detailed investigation changing the content of moisture (H2O) and carbon dioxide (CO2) as well as the temperature. The tests are operated at a temperature range between 700 and 1000°C, H2O-concentrations from 0 to 80 vol% and CO2-concentrations also in the range of 0 to 80 vol%. These systematic experimental variations provide the basis for a model of the reaction kinetics of biochar under different boundary conditions. The data is to be evaluated via the generic model including temperature and the partial pressures of CO2 and H2O. Afterwards it will be matched with conventional models (e.g. Arrhenius plot, linear regression models) to determine their suitability. One of those models was used in the paper of Ollero et al, where the influence of CO2 on the reaction kinetics of olive residue was investigated. 1First results show that the reaction rate of biochar is much lower than the one of olive residue. Effects of treatment conditions on the surface properties are investigated by taking out the treated samples after a defined treatment period at a defined mass loss and subsequent surface analysis (BET, pore size/volume distribution) of the samples. In first BET surface analysis, the treatments of biochar with vapour lead to a surface of approximately 1000m²/g whereas the original sample has a BET surface lower than 150m²/g. This finding leads to the question how the reaction kinetics of a treatment process influences the surface change. The obtained data is taken as basis for developing an upgrading process for biochar to a high value product of the gasification process. In order to prove the suitability of TGA-tests for identifying optimised treatment conditions, further research shall demonstrate the correlation of the lab-scale TGA-results with experiences of pilot scale tests.
 


Conference contributions | 2020

Biofuels for transport decarbonisation Country specific assessment for Finland, Sweden, Germany, USA and Brazil

Matschegg D, Biofuels for transport decarbonisation Country specific assessment for Finland, Sweden, Germany, USA and Brazil. 6th Central European Biomass Conference, 22-24 January 2020, Graz.

Download PDF

Details


Conference contributions | 2020

Biological Methanation Processes

Drosg B, Wellinger A. Biological Methanation Processes. 28th European Biomass Conference and Exhibition (oral presentation) 2020.

Details


Peer Reviewed Scientific Journals | 2020

Biomass pyrolysis TGA assessment with an international round robin

Anca-Couce A, Tsekos C, Retschitzegger S, Zimbardi F, Funke A, Banks S, Kraia T, Marques P, Scharler R, de Jong W, Kienzl N. Biomass pyrolysis TGA assessment with an international round robin.Fuel.2020;276:118002.https://doi.org/10.1016/j.fuel.2020.118002

External Link

Details

The large variations found in literature for the activation energy values of main biomass compounds (cellulose, hemicellulose and lignin) in pyrolysis TGA raise concerns regarding the reliability of both the experimental and the modelling side of the performed works. In this work, an international round robin has been conducted by 7 partners who performed TGA pyrolysis experiments of pure cellulose and beech wood at several heating rates. Deviations of around 20 – 30 kJ/mol were obtained in the activation energies of cellulose, hemicellulose and conversions up to 0.9 with beech wood when considering all experiments. The following method was employed to derive reliable kinetics: to first ensure that pure cellulose pyrolysis experiments from literature can be accurately reproduced, and then to conduct experiments at different heating rates and evaluate them with isoconversional methods to detect experiments that are outliers and to validate the reliability of the derived kinetics and employed reaction models with a fitting routine. The deviations in the activation energy values for the cases that followed this method, after disregarding other cases, were of 10 kJ/mol or lower, except for lignin and very high conversions. This method is therefore proposed in order to improve the consistency of data acquisition and kinetic analysis of TGA for biomass pyrolysis in literature, reducing the reported variability.


Conference contributions | 2020

Challenges and recent results in microalgae research

Meixner K. Challenges and recent results in microalgae research. 6th Central european biomass conference, 2020, Graz.

Download PDF

Details


Conference contributions | 2020

CleanAir by biomass

Sturmlechner R, Stressler H, Golicza L, Reichert G, Schwabl M, Höftberger E, Kelz J. CleanAir by biomass. 6th Central European Biomass Conference, 2020, Graz.

External Link

Download PDF

Details


Peer-reviewed publications | 2020

Combined influence of inorganics and transport limitations on the pyrolytic behaviour of woody biomass

Almuina-Villar H, Sommersacher P, Retschitzegger S, Anca-Couce A, Dieguez-Alonso A. Combined influence of inorganics and transport limitations on the pyrolytic behaviour of woody biomass. Chemical Engineering Transactions. 2020.80:73-78

External Link

Details

A deeper understanding and quantification on the influence of inorganic species on the pyrolysis process, combined with the presence of heterogeneous secondary reactions, is pursued in this study. Both chemical controlled and transport limited regimes are considered. The former is achieved in a thermogravimetric analyser (TGA) with fine milled biomass in the mg range, while the latter is investigated in a particle level reactor with spherical particles of different sizes. To account for the influence of inorganics, wood particles were washed and doped with KCl aqueous solutions, resulting in K concentrations in the final wood of around 0.5% and 5% on dry basis. Gas species and condensable volatiles were measured online with Fourier transform infrared (FTIR) spectroscopy and a non-dispersive infrared (NDIR) gas analyzer. The removal of inorganic species delayed the pyrolysis reaction to higher temperatures and lowered char yields. The addition of inorganics (K) shifted the devolatilization process to lower temperatures, increased char and water yields, and reduced CO production among others. Higher heating rates and temperatures resulted in lower char, water, and light condensable yields, but significantly higher CH4 and other light hydrocarbons, as well as CO. The increase in these yields can be attributed, at least in part, to the gas phase cracking reactions of the produced volatiles. Larger particle size increased the formation of char, CH4 and other light hydrocarbons, and light condensables for low and high pyrolysis temperatures, while reduced the release of CO2 and H2O. This novel data set allows to quantify the influence of each parameter and can be used as basis for the development of detailed pyrolysis models which can include both the influence of inorganics and transport limitations when coupled into particle models.


Peer Reviewed Scientific Journals | 2020

Consequential Life Cycle Assessment of energy generation from waste wood and forest residues: The effect of resource-efficient additives

Corona B, Shen L, Sommersacher P, Junginger M. Consequential Life Cycle Assessment of energy generation from waste wood and forest residues: The effect of resource-efficient additives. Journal of Cleaner Production 2020. 259:120948.

External Link

Details

Combustion of waste wood can cause slagging, fouling and corrosion which lead to boiler failure, affecting the energy efficiency and the lifetime of the power plant. Additivation with mineral and sulfur containing additives during waste wood combustion could potentially reduce these problems. This study aims at understanding the environmental impacts of using additives to improve the operational performance of waste wood combustion. The environmental profiles of four energy plants (producing heat and/or power), located in different European countries (Poland, Austria, Sweden and Germany), were investigated through a consequential life cycle assessment (LCA). The four energy plants are all fueled by waste wood and/or residues. This analysis explored the influences of applying different additives strategies in the four power plants, different wood fuel mixes and resulting direct emissions, to the total life cycle environmental impacts of heat and power generated. The impacts on climate change, acidification, particulate matter, freshwater eutrophication, human toxicity and cumulative energy demand were calculated, considering 1 GJ of exergy as functional unit. Primary data for the operation without additives were collected from the power plant operators, and emission data for the additives scenarios were collected from onsite measurements. A sensitivity analysis was conducted on the expected increase of energy efficiency. The analysis indicated that the use of gypsum waste, halloysite and coal fly ash decreases the environmental impacts of heat and electricity produced (average of 12% decrease in all impacts studied, and a maximum decrease of 121%). The decrease of impacts is mainly a consequence of the increase of energy generation that avoids the use of more polluting marginal technologies. However, impacts on acidification may increase (up to 120% increase) under the absence of appropriate flue gas cleaning systems. Halloysite was the additive presenting the highest benefits.


Peer Reviewed Scientific Journals | 2020

Control of biomass grate boilers using internal model control

Schörghuber C, Gölles M, Reichhartinger M, Horn M. Control of Biomass Grate Boilers using Internal Model Control. Control engineering practice. 2020.

External Link

Details

A new model-based control strategy for biomass grate boilers is presented in this paper. Internal model control is used to control four outputs of the plant and to achieve a control structure with fewer control parameters needing to be experimentally tuned. A nonlinear state–space model describing the essential behaviour of the biomass grate boiler is used for controller design. The inverse system dynamics representing the main part of internal model control are designed with the help of this model. In doing so the properties of differentially flat systems are used. Due to a time delayed input, the inverse system is determined only for three input output channels. The stabilization of the inverse system dynamics, however, is a challenging task. A stabilization method with the help of the time delayed input is suggested and a stability analysis is given. The new control strategy has only three parameters to be tuned, representing a major reduction of complexity in comparison to existing model-based approaches. Finally, experimental results of the implemented control strategy on representative biomass grate boiler with a nominal capacity of 180 kW are presented and compared to an existing model-based control strategy based on input output linearization. The experimental evaluation proves that it is possible to operate the biomass boiler in all load ranges with high efficiency and low pollutant emissions.


Peer Reviewed Scientific Journals | 2020

Correction to: Investigation of solid oxide fuel cell operation with synthetic biomass gasification product gases as a basis for enhancing its performance

Pongratz G, Subotić V, Schroettner H, Stoeckl B, Hochenauer C, Anca-Couce A, Scharler R. Correction to: Investigation of solid oxide fuel cell operation with synthetic biomass gasification product gases as a basis for enhancing its performance. Biomass Conversion and Biorefinery. 2020

External Link

Details

The authors want to acknowledge, that during the production of the final version of the publication the image for Figure 9 has been replaced with the image for Figure 12, however without changing the content of the paper. This issue is resolved in the current version of the publication.


Conference contributions | 2020

Customizing biomass as reducing agent in blast furnace steelmaking – Reduction potential and fluidization

Deutsch R, Strasser C, Martini S, Kienzl N. Customizing biomass as reducing agent in blast furnace steelmaking – Reduction potential and fluidization. 28th European Biomass Conference and Exhibition (oral presentation) 2020.

Details

The reduction of greenhouse gas emissions is an important issue for iron and steel industry. One possibility is to use biomass-based reducing agents, also called bioreducers, to replace at least partly the fossil reducer agents. In a first step woody biomass was treated in a lab-scale muffle furnace and afterwards ground with a ball mill. The powder characteristics were investigated in respect to the flow behavior. For a certain treatment temperature the particle size distribution and as well the flow behavior shows similarities to lignite. The next stage was to identify relations between powder characteristics and its fluidization behavior. A fluidization device was assembled and used to determine the minimum fluidization gas velocity for various bioreducer powders.


Conference contributions | 2020

Das neue Holzwärmeszenario "Holz ersetzt Heizöl"

Schmidl C, Reichert G. Das neue Holzwärmeszenario "Holz ersetzt Heizöl". World Sustainable Energy Days 2020, Wels, Austria (oral presentation). 2020.

Details


Peer Reviewed Scientific Journals | 2020

Decentralized heating grid operation: A comparison of centralized and agent-based optimization

Lichtenegger K, Leitner A, Märzinger T, Mair C, Moser A, Wöss D, Schmidl C, Pröll T. Decentralized heating grid operation: A comparison of centralized and agent-based optimization. Sustainable Energy, Grids and Networks. 2020;2020(21).

External Link

Details

Moving towards a sustainable heat supply calls for decentralized and smart heating grid solutions. One promising concept is the decentralized feed-in by consumers equipped with their own small production units (prosumers). Prosumers can provide an added value regarding security of supply, emission reduction and economic welfare, but in order to achieve this, in addition to advanced hydraulic control strategies also superordinate control strategies and appropriate market models become crucial.

In this article we study methods to find a global optimum for the local energy community or at least an acceptable approximation to it. In contrast to standard centralized control approaches, based either on expert rules or mixed integer linear optimization, we adopt an agent-based, decentralized approach that allows for incorporation of nonlinear phenomena. While studied here in small-scale systems, this approach is particularly attractive for larger systems, since with an increasing number of interacting units, the optimization problem becomes more complex and the computational effort for centralized approaches increases dramatically.

The agent-based optimization approach is compared to centralized optimization of the same prosumer-based setting as well as to a purely central setup. The comparison is based on the quality of the optimization solution, the computational effort and the scalability. For the comparison of these three approaches, three different scenarios have been set up and analysed for four seasons. In this analysis, no approach has emerged as clearly superior to the others; thus each of them is justified in certain situations.


Peer Reviewed Scientific Journals | 2020

Detailed experimental investigation of the spatially distributed gas release and bed temperatures in fixed-bed biomass combustion with low oxygen concentration

Archan G, Anca-Couce A, Gregorc J, Buchmayr M, Hochenauer C, Gruber J, Scharler R. Detailed experimental investigation of the spatially distributed gas release and bed temperatures in fixed-bed biomass combustion with low oxygen concentration. Biomass and Bioenergy. 2020;141:105725

External Link

Details

This publication focuses on the experimental investigation of a novel small-scale fuel flexible biomass combustion technology with a fixed-bed employing a low oxygen concentration. It was obtained through a low primary air ratio and the additional supply of recirculated flue gas. The plant was operated with spruce wood chips, which contained three different mass fractions of water, and miscanthus pellets. All relevant components of the released gas above the fixed-bed were measured, as well as the 3D bed temperature distribution. The balances confirmed a high experimental data consistency. Therefore, it was possible to determine the location of the four different conversion zones inside the fixed-bed: drying, pyrolysis, char gasification and char oxidation. The reduction of CO2 to CO in the char reduction zone worked efficiently across the entire grate area. Furthermore, the results showed that the water mass fraction of the fuel did not influence the dry product gas composition, but significantly affected the location for the release of pyrolysis products such as tars. It was found that the low oxygen concentration in the fixed-bed combined with flue gas recirculation was an effective method to reduce bed temperatures and therefore its inorganic emissions while significantly increasing feedstock flexibility. The investigations provided fundamental findings on the conversion and release behavior of the new technology under real operating conditions and are very useful for further experimental work and CFD simulations targeting the reduction of PM and NOX emissions.


Conference contributions | 2020

Detailed investigations of high terpene concetrations in biogas laboratory trials

Knoll L, Sumethberger-Hasinger M, Nussbaumer M, Dalnodar D, Loibner A, Drosg B. Detailed investigations of high terpene concetrations in biogas laboratory trials. 6th Central European Biomass Conference, 22-24 January 2020, Graz.

Download PDF

Details


Peer Reviewed Scientific Journals | 2020

Developing an adsorption-based gas cleaning system for a dual fluidized bed gasification process

Loipersböck J, Weber G, Rauch R, Hofbauer H. Developing an adsorption-based gas cleaning system for a dual fluidized bed gasification process.Biomass Conversion and Biorefinery. 2020.

External Link

Details

Biomass has the potential to make a major contribution to a renewable future economy. If biomass is gasified, a wide variety of products (e.g., bulk chemicals, hydrogen, methane, alcohols, diesel) can be produced. In each of these processes, gas cleaning is crucial. Impurities in the gas can cause catalyst poisoning, pipe plugging, unstable or poisoned end products, or harm the environment. Aromatic compounds (e.g., benzene, naphthalene, pyrene), in particular, have a huge impact on stable operation of syngas processes. The removal of these compounds can be accomplished by wet, dry, or hot gas cleaning methods. Wet gas cleaning methods tend to produce huge amounts of wastewater, which needs to be treated separately. Hot gas cleaning methods provide a clean gas but are often cost intensive due to the high operating temperatures and catalysts used in the system. Another approach is dry or semi-dry gas cleaning methods, including absorption and adsorption on solid matter. In this work, special focus was laid on adsorption-based gas cleaning for syngas applications. Adsorption and desorption test runs were carried out under laboratory conditions using a model gas with aromatic impurities. Adsorption isotherms, as well as dynamics, were measured with a multi-compound model gas. Based on these results, a temperature swing adsorption process was designed and tested under laboratory conditions, showing the possibility of replacing conventional wet gas cleaning with a semi-dry gas cleaning approach.


Conference Papers | 2020

Development and experimental validation of a linear state-space model for absorption heat pumping systems for model-based control strategies

Zlabinger S, Unterberger V, Gölles M, Horn M, Wernhart M, Rieberer R. Development and experimental validation of a linear state-space model for absorption heat pumping systems for model-based control strategies. International Sorption Heat Pump Conference 2020.

External Link

Details

Control strategies of absorption heat pumping systems (AHPS, comprising heat pumps and chillers) often
perform insufficiently well, since they usually do not explicitly consider the systems’ dynamics and crosscoupling effects. One promising approach to improve their performance is to apply model-based control strategies since they would allow for an explicit consideration of these system characteristics. Therefore, mathematically simple models of the system to be controlled are required. This contribution proposes a new approach for such a model for a H2O-LiBr AHPS. The model results from the linearization of a more complex, nonlinear simulation model, leading to a simple, but physically still meaningful linear state-space model structure. The experimental validation shows that the developed model describes the system’s dynamics and cross-coupling effects sufficiently well and indicates that it is suitable to serve as a basis for the development of a model-based control strategy for AHPS.