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Other Publications | 2021

Modelling and control of large-scale solar thermal systems

Unterberger V. Modelling and control of large-scale solar thermal systems. 2021. 212 p.

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Heat makes up the largest share of energy end-use, accounting for 50% of global final energy consumption in 2018 and contributing to about 40% of global carbon dioxide (CO2) emissions. Of the total heat produced, about 46% was consumed in buildings for space and water heating. Large-scale solar thermal systems provide a highly valuable possibility to increase the share of renewables in heating systems and to reduce carbon dioxide emissions. In this context, the worldwide number of large-scale solar heating systems has increased rapidly in the last couple of years, especially in China and European countries, e.g. in Denmark. This has led to the installation of about 400 large-scale solar thermal systems ( ≥ 350kWth, 500m²) by the end of 2019.
Unlike other heating systems, their main source of power (solar radiation) cannot be manipulated and is subject to changes on a seasonal as well as on a daily basis. That is why control systems play a very important role for the efficient operation of these systems. This thesis therefore focuses on the application of model-based control strategies, and the necessary preliminary work regarding modelling, in order to achieve an efficient control of large-scale solar thermal systems. Consequently, the thesis addresses three important aspects:
In the first main section, models of components of large-scale solar thermal systems are developed and validated. For the most important components (heat exchanger, solar collector and sensible heat storage), two models of different complexity, one simulation-oriented, one control-oriented, are developed. While the simulation-oriented models aim to model the physical behaviour very accurately in order to be used in simulation studies, control-oriented models aim to model the physical behaviour only as accurately as necessary in order to serve as a basis for model-based control strategies. All models are validated with measurement data from a typical solar system, and it is shown that they are sufficiently accurate for their intended purpose. The sum of the models provides a holistic view on all modelling aspects that have to be considered in large-scale solar thermal plants, and serves as a reasonable basis for model-based control strategies and accurate simulation studies of solar systems.
In the second main section, adaptive forecasting methods for the future solar heat production as well as the heat demand are developed and validated with measurement data and using real weather forecasts. These methods are important to most efficiently integrate and operate solar systems by better scheduling heat production, storage and distribution for the near future. In order to be used in real-world applications, the methods are developed with the goal to meet three important practical requirements: simple implementation, automatic adaption to seasonal changes, and wide applicability. The final long-term evaluation for half a year proves that the developed methods can forecast the solar heat production as well as the heat demand very accurately and outperform common forecasting methods, yielding results that are nearly twice as accurate.
In the third main section, model-based control strategies for the high-level as well as for the low-level control of solar thermal systems are developed and validated. For the high-level control an approach is presented which considers future information by using the developed forecasting methods. It achieves higher profits (plus 3 %) and leads to a more stable operation, compared to the existing commercial solution. For the low-level control, model-based control strategies based on the developed models for the heat generation and distribution are presented. The model-based control strategy for the heat generation considers the dynamic behaviour of the collector and especially considers the variable time-delay. This, compared to conventional control strategies, leads to a significantly better control performance in case of fluctuating solar radiation and changing inlet temperatures. The model-based control strategy for the heat distribution follows a modular approach which can be applied for several hydraulic settings, leading to an accurate and independent control of mass flow and temperature, and outperforms state-of-the-art control strategies. For both control levels, care was taken that the applied strategies can be used in real-world applications regarding their mathematical complexity and computational resources required.
In summary, this thesis presents a holistic approach regarding modelling (simulation-oriented models, control-oriented models and adaptive forecasting methods) and control aspects (high-level as well as low-level control) which can help to improve the efficiency of large-scale solar thermal plants on various levels, making them more competitive, and is furthermore essential for a successful integration of these plants in larger energy systems.


Peer Reviewed Scientific Journals | 2021

Modelling fuel flexibility in fixed-bed biomass conversion with a low primary air ratio in an updraft configuration

Anca-Couce A, Archan G, Buchmayr M, Essl M, Hochenauer C, Scharler R. Modelling fuel flexibility in fixed-bed biomass conversion with a low primary air ratio in an updraft configuration. Fuel. 2021.296:120687.

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Fixed-bed biomass conversion with a low primary air ratio and a counter-current configuration has a high feedstock flexibility, as it resembles updraft gasification, and the potential to reduce emissions when integrated in biomass combustion systems. A 1D bed model was validated with experimental results from a biomass combustion boiler with such a bed conversion system, predicting with a good accuracy the temperatures in the reactor and producer gas composition. The model was applied for different cases to investigate the fuel flexibility of this combustion system, including the influence of moisture content and the maximum temperatures achieved in the bed. It was shown that with variations in fuel moisture content from 8 to 30% mass w.b. the producer gas composition, char reduction to CO or maximum temperatures at the grate were not affected due to the separation of the char conversion and pyrolysis/drying zones. Flue gas recirculation was the only possible measure with the tested configuration to reduce the maximum temperatures close to the grate, which is beneficial e.g. to avoid slagging with complicated fuels. A higher tar content was obtained than in conventional updraft gasifiers, which is attributed to the absence of tar condensation in the bed due to the limited height of the reactor and the integration in the combustion chamber. The presented model can support the development of such combustion technologies and is a relevant basis for detailed CFD simulations of the bed or gas phase conversion.


Peer Reviewed Scientific Journals | 2021

Operation of coupled multi-owner district heating networks via distributed optimization

Kaisermayer V, Muschick D, Horn M, Gölles M. Operation of coupled multi-owner district heating networks via distributed optimization. Energy Reports. 2021 Okt;7(Suppl. 4):273-281. https://doi.org/10.1016/j.egyr.2021.08.145

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The growth of district heating and cooling (DHC) networks introduces the possibility of connecting them with neighbouring networks. Coupling networks can save costs by reducing operating hours of peak load or backup boilers, or free up production capacity for network expansion. Optimization-based energy management systems (EMS) already provide operators of individual DHC networks with solutions to the unit commitment and economic dispatch problem. They are especially useful for complex networks with multiple producers and integrated renewable energy sources, where incorporating forecasts is important. Time-dependent constraints and network capacity limitations can easily be considered. For coupled networks, a centralized optimization would provide a minimum with respect to an objective function which can incorporate fuel costs, operational costs and costs for emissions. However, the individual coupled networks are generally owned by different organizations with competing objectives. The centralized solution might not be accepted, as each company aims to optimize its own objective. Additionally, all data has to be shared with a centralized EMS, and it represents a single point of failure. A decentralized EMS may therefore be a better choice in a multi-owner setting. In this article, a novel decentralized EMS is presented that can handle multi-owner structures with cooperative and non-cooperative coupling. Each local EMS solves its own optimization problem, and an iterative Jacobi-style algorithm ensures consensus among the networks. The distributed EMS is compared to a centralized EMS based on a representative real-world example consisting of three coupled district heating networks operated by two companies.


Other Presentations | 2021

Operation of Coupled Multi-Owner District Heating Networks via Distributed Optimization

Muschick D, Gölles M, Kaisermayer V, Horn M. Operation of Coupled Multi-Owner District Heating Networks via Distributed Optimization.17th International Symposium on District Heating and Cooling. Nottingham Trent University, Nottingham, United Kingdom. 7. Sep 2021. Oral Presentation. [online]

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The simultaneous operation of multiple connected heating networks can be handled by optimization techniques. However, a global optimum might not represent a good operating strategy if the networks belong to different owners and thus might habe competing interests. An approach from game theory then needs to be applied, which finds a generalized Nash equilibrium instead.


Technical Reports | 2021

OptEnGrid Optimal integration of heat, electricity and gas systems to increase efficiency and reliability

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OptEnGrid is a cross-sectoral multi-energy system optimization tool for the optimal planning and dispatch of the Distributed Energy Resource (DER) technologies in smart- and microgrids. The methodology of OptEnGrid considers an optimization model which is based on Mixed-Integer Linear Programming (MILP) framework. The following sub-sections provide more details about the energy flow and system optimization inside OptEnGrid and the choice of the optimization over simulation


Other Presentations | 2021

Optimal operation of cross-ownership district heating and cooling networks

Muschick D, Kaisermayer V, Gölles M, Horn M.Optimal operation of cross-ownership district heating and cooling networks. 20th European Roundtable on Sustainable Consumption and Production. 9. Sep 2021. Graz. Oral Presentation.

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Conference contributions | 2021

Optimal operation of cross-ownership district heating and cooling networks

Kaisermayer V, Muschick D, Gölles M, Horn M. Optimal operation of cross-ownership district heating and cooling networks. 17th International Symposium on District Heating and Cooling: DHC 2021. 7 Sep 2021. Oral presentation.

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Peer Reviewed Scientific Journals | 2021

Optimal planning of thermal energy systems in a microgrid with seasonal storage and piecewise affine cost functions

Mansoor M, Stadler M, Zellinger M, Lichtenegger K, Auer H, Cosic A. Optimal planning of thermal energy systems in a microgrid with seasonal storage and piecewise affine cost functions. Energy. 2021:215;119095.

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The optimal design of microgrids with thermal energy system requires optimization techniques that can provide investment and scheduling of the technology portfolio involved. In the modeling of such systems with seasonal storage capability, the two main challenges include the low temporal resolution of available data and the non-linear cost versus capacity relationship of solar thermal and heat storage technologies. This work overcomes these challenges by developing two different optimization models based on mixed-integer linear programming with objectives to minimize the total energy costs and carbon dioxide emissions. Piecewise affine functions are used to approximate the non-linear cost versus capacity behavior. The developed methods are applied to the optimal planning of a case study in Austria. The results of the models are compared based on the accuracy and real-time performance together with the impact of piecewise affine cost functions versus non-piecewise affine fixed cost functions. The results show that the investment decisions of both models are in good agreement with each other while the computational time for the 8760-h based model is significantly greater than the model having three representative periods. The models with piecewise affine cost functions show larger capacities of technologies than non-piecewise affine fixed cost function based models.


Technical Reports | 2021

Planung zellularer Energiesysteme

Teil 1: Effektive integrierte Investitions- und Betriebsplanung von Energiezellen

VDE Verband der Elektrotechnik e.V. Energietechnische Gesellschaft (ETG)

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In einem zellularen Energiesystem wird die physikalische Balance zwischen Energieangebot und -nachfrage so weit als möglich bereits auf regionaler, lokaler Ebene hergestellt. Der zentrale Baustein dabei ist die Energiezelle. Sie kann Energie in Form von Wärme, Elektrizität oder Gas aufnehmen und/oder Elektrizität und Wärme (z. B. aus erneuerbaren Energien) selbst erzeugen, um so den eigenen Wärme- und Elektrizitätsbedarf zu decken. Energieüberschüsse können (elektrisch und/oder thermisch) gespeichert oder anderen Zellen im Nahbereich oder einem Energieversorger zur Verfügung gestellt werden. Ein Energiezellenmanagement kann in Koordination mit Nachbarzellen den Ausgleich von Erzeugung und Verbrauch über alle vorhandenen Energieformen organisieren.
Die Planung und der Betrieb zellularer Energiesysteme ist eine komplexe Aufgabe, da eine Vielzahl von dezentralen Energietechnologien, verschiedenste Ziele und auch Entscheidungsträger berück-sichtigt werden müssen.
Der vorliegende VDE Impuls beschreibt als ersten Schritt die Planung einer Energiezelle, welche mit Energieversorgern interagieren kann. Er ist der Auftakt einer Reihe weiterer Veröffentlichungen zur detaillierten Planung von Energiezellen und zellularen Energiesystemen.


Peer Reviewed Scientific Journals | 2021

Real-life emissions from residential wood combustion in Austria: From TSP emissions to PAH emission profiles, diagnostic ratios and toxic risk assessment

B Kirchsteiger, F Kubik, R Sturmlechner, H Stressler, M Schwabl, M Kistler, A Kasper-Giebl. Real-life emissions from residential wood combustion in Austria: From TSP emissions to PAH emission profiles, diagnostic ratios and toxic risk assessment. Atmospheric Pollution Research. 2021.12:8.

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Residential wood combustion is, besides particulate emissions, also linked to emissions of organic compounds, comprising various toxic substances such as polycyclic aromatic hydrocarbons (PAHs). Although, literature data has shown that highest emissions occur during maloperations caused by the user itself, most studies focus on lab-testing not reflecting the situation in the field. This study evaluates the real-life situation in Austria, investigating emissions of total suspended particles (TSP) and particle-bound substances of four manually operated room heaters commonly installed in people's homes. Measurements were conducted within a field measurement campaign realized in the scope of the Clean Air by biomass project. To evaluate the impact of the users' habit two types of combustion experiments were performed, one representing the diversity of possible maloperations and one realized under optimized conditions following a strict optimization protocol. As special focus was laid on PAHs, sampling was realized using a dilution system adapted for the use in the field. Generally, optimization lead to a clear decrease of most compounds (i.e. TSP, OC, EC, PAHs), however, emissions of the anhydrosugar levoglucosan were not affected at all. Total PAH emissions could be clearly reduced, moreover, optimization lead to a shift towards low molecular weight PAHs and thus, less toxic ones, clearly reflected by lower toxicity equivalents. Correlation analysis using the Spearman's rank method showed significantly high correlations among the individual PAH congeners, and rather low ones with other target substances.


Peer Reviewed Scientific Journals | 2021

Single Pellet Combustion of Sewage Sludge and Agricultural Residues with a Focus on Phosphorus

Häggström G, Hannl TK, Hedayati A, Kuba M, Skoglund N, Öhman M. Single Pellet Combustion of Sewage Sludge and Agricultural Residues with a Focus on Phosphorus. Energy & Fuels. 8 June 2021.

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Recycling of phosphorus in combination with increased utilization of bioenergy can mitigate material and global warming challenges. In addition, co-combustion of different fuels can alleviate ash-related problems in thermal conversion of biomass. The aim of this study is to investigate the ash transformation reactions of mainly P in co-combustion of P-rich sewage sludge (SS) with K-rich sunflower husks (SH) and K- and Si-rich wheat straw (WS). Single pellets of 4 mixtures (10 and 30 wt % SS in WS and 15 and 40 wt % SS in SH) and pure SS were combusted in an electrically heated furnace at process temperatures relevant for fluidized bed combustion (800 and 950 °C). Collected ash fractions were analyzed by inductively coupled plasma techniques, ion chromatography, scanning electron microscopy–energy-dispersive X-ray spectroscopy, and X-ray diffraction. Thermodynamic equilibrium calculations were performed to interpret the results. Over 90% of K and P was found to be captured within the residual ash with 30–70% P in crystalline K-bearing phosphates for mixtures with low amounts of SS (WSS10 and SHS15). The significant share of K and P in the amorphous material could be important for P recovery. For the lower percentage mixtures of SS (WSS10 and SHS15), P in crystalline phases was mainly found in K-whitlockite and CaKPO4. For the higher percentage SS mixtures, most of P was found in whitlockites associated with Fe and Mg, and no crystalline phosphates containing K were detected. For P recovery, co-combustion of the lower SS mixtures is favorable, and they are suggested to be further studied concerning the suitability for plant growth.


Peer Reviewed Scientific Journals | 2021

Steam gasification of biomass – Typical gas quality and operational strategies derived from industrial-scale plants

Larsson A, Kuba M, Berdugo Vilches T, Seemann M, Hofbauer H, Thunman H. Steam gasification of biomass – Typical gas quality and operational strategies derived from industrial-scale plants. Fuel Processing Technology. 2021.212:106609.

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Steam gasification enables the thermochemical conversion of solid fuels into a medium calorific gas that can be utilized for the synthesis of advanced biofuels, chemicals or for heat and power production. Dual fluidized bed (DFB) gasification is at present the technology applied to realize gasification of biomass in steam environment at large scale. Few large-scale DFB gasifiers exist, and this work presents a compilation and analysis of the data and operational strategies from the six DFB gasifiers in Europe. It is shown that the technology is robust, as similar gas quality can be achieved despite the differences in reactor design and operation strategies. Reference concentrations of both gas components and tar components are provided, and correlations in the data are investigated. In all plants, adjusting the availability and accessibility to the active ash components (K and Ca) was the key to control the gas quality. The gas quality, and in particular the tar content of the gas, can conveniently be assessed by monitored the concentration of CH4 in the produced gas. The data and experience acquired from these plants provide important knowledge for the future development of the steam gasification of biomass.


Technical Reports | 2021

Supervisory control of large-scale solar thermal systems

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

Gölles M, Unterberger V, Kaisermayer V, Nigitz T, Muschick D. "Supervisory control of large-scale solar thermal systems". IEA SHC FACTSHEET 55.A-D4.1. Date of Publication: 28.01.2021. https://task55.iea-shc.org/fact-sheets

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Overview on different approaches for supervisory control strategies,deciding on operating modes and set points for the controls of the different plants and componentsintegrated in solar thermal systems.


Technical Reports | 2021

Tailoring of the pore structures of wood pyrolysis chars for potential use in energy storage applications

Maziarka P, Sommersacher P, Wang X, Kienzl N, Retschitzegger S, Prins W, Hedin N, Ronsse F. Tailoring of the pore structures of wood pyrolysis chars for potential use in energy storage applications. Applied Energy.2021.286:116431. https://doi.org/10.1016/j.apenergy.2020.116431

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Char obtained from biomass pyrolysis is an eco-friendly porous carbon, which has potential use as a material for electrodes in supercapacitors. For that application, a high microporous specific surface area (SSA) is desired, as it relates to the accessible surface for an applied electrolyte. Currently, the incomplete understanding of the relation between porosity development and production parameters hinders the production of tailor-made, bio-based pyrochars for use as electrodes. Additionally, there is a problem with the low reliability in assessing textual properties for bio-based pyrochars by gas adsorption. To address the aforementioned problems, beech wood cylinders of two different lengths, with and without pre-treatment with citric acid were pyrolysed at temperatures of 300–900 °C and analysed by gas adsorption. The pyrolyzed chars were characterised with adsorption with N2 and CO2 to assess the influence of production parameters on the textual properties. The new approach in processing the gas adsorption data used in this study demonstrated the required consistency in assessing the micro- and mesoporosity. The SSA of the chars rose monotonically in the investigated range of pyrolysis temperatures. The pre-treatment with citric acid led to an enhanced SSA, and the length of the cylinders correlated with a reduced SSA. With pyrolysis at 900 °C, the micro-SSAs of samples with 10 mm increased by on average 717 ± 32 m2/g. The trends among the investigated parameters and the textual properties were rationalized and provide a sound basis for further studies of tailor-made bio-based pyrochars as electrode materials in supercapacitors.


Peer Reviewed Scientific Journals | 2021

Techno-economic optimization of islanded microgrids considering intra-hour variability

Mathiesen P, Stadler M, Kleissl J, Pecenak Z. Techno-economic optimization of islanded microgrids considering intra-hour variability. Applied Energy. 2021.304:117777.

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The intra-hour intermittency of solar energy and demand introduce significant design challenges for microgrids. To avoid costly energy shortfalls and mitigate outage probability, islanded microgrids must be designed with sufficient distributed energy resources (DER) to meet demand and fulfill the energy and power balance. To avoid excessive runtime, current design tools typically only utilize hourly data. As such, the variable nature of solar and demand is often overlooked. Thus, DER designed based on hourly data may result in significant energy shortfalls when deployed in real-world conditions. This research introduces a new, fast method for optimizing DER investments and performing dispatch planning to consider intra-hour variability. A novel set of constraints which operate on intra-hour data are implemented in a mixed-integer-linear-program microgrid investment optimization. Variability is represented by the single worst-case intra-hour fluctuation. This allows for fast optimization times compared to other approaches tested. Applied to a residential microgrid case study with 5-minute intra-hour resolution, this new method is shown to maintain optimality within 2% and reduce runtime by 98.2% compared to full-scale-optimizations which consider every time-step explicitly. Applicable to a variety of technologies and demand types, this method provides a general framework for incorporating intra-hour variability into microgrid design.


Conference Papers | 2021

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

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

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


Peer Reviewed Scientific Journals | 2021

Ultra-low temperature water-gas shift reaction catalyzed by homogeneous Ru-complexes in a membrane reactor - membrane development and proof of concept

Logemann M, Wolf P, Loipersböck J, Schrade A, Wessling M, Haumann M. Ultra-low temperature water-gas shift reaction catalyzed by homogeneous Ru-complexes in a membrane reactor - membrane development and proof of concept. Catalysis Science and Technology. 2021.11(4):1558-1570. https://doi.org/10.1039/D0CY02111C

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A monolithic membrane reactor combining the supported ionic liquid-phase (SILP) catalyzed ultra-low temperature water–gas shift reaction (WGSR) with in situ product removal is presented. The SILP catalyst consists of the transition metal complex [Ru(CO)3Cl2]2 homogeneously dissolved in 1-butyl-2,3-dimethylimidazolium chloride [C4C1C1Im]Cl and supported on alumina pellets. These Ru-SILP pellets are deposited inside the channels of a silicon carbide monolith. The resulting monolithic catalyst is very active and stable in the WGSR in the temperature range between 120 and 160 °C, thereby making full use of the high equilibrium conversion at these conditions. A facilitated transport membrane was coated onto the smooth outside of the SiC monolith to allow preferential removal of CO2 compared to H2. The proof of this concept has been shown under industrially relevant conditions using a biogas feed. These results demonstrate, for the first time, the combination of homogeneous SILP catalyzed WGSR with enhanced in situ removal of one of the products (here: CO2) via facilitated transport membrane separation.


Peer Reviewed Scientific Journals | 2021

Valorisation of starch wastewater by anaerobic fermentation

Drosg B, Neubauer M, Marzynski M, Meixner K. Valorisation of starch wastewater by anaerobic fermentation. Applies Sciences (Switzerland). 2021.11(21):10482.

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Starch production is mainly focused on feedstocks such as corn, wheat and potato in the EU, whereas cassava, rice, and other feedstocks are utilised worldwide. In starch production, a high amount of wastewater is generated, which accumulates from different process steps such as washing, steeping, starch refining, saccharification and derivatisation. Valorisation of these wastewaters can help to improve the environmental impact as well as the economics of starch production. Anaerobic fermentation is a promising approach, and this review gives an overview of the different utilisation concepts outlined in the literature and the state of the technology. Among bioenergy recovery processes, biogas technology is widely applied at the industrial scale, whereas biohydrogen production is used at the research stage. Starch wastewater can also be used for the production of bulk chemicals such as acetone, ethanol, butanol or lactic acids by anaerobic microbes.


Conference contributions | 2020

"Long-term verification of a new modular method for CO-lambda-optimisation"

Zemann C, Hammer F, Gölles M. Long-term verification of a new modular method for CO-lambda-optimisation. 6th Central European Biomass Conference CEBC 2020 (Oral Presentation). 2020.

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Peer Reviewed Scientific Journals | 2020

A MILP-based modular energy management system for urban multi-energy systems: Performance and sensitivity analysis

Moser AGC, Muschick D, Gölles M, Nageler PJ, Schranzhofer H, Mach T et al. A MILP-based modular energy management system for urban multi-energy systems: Performance and sensitivity analysis. Applied Energy. 2020;2020(261). 114342.

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The continuous increase of (volatile) renewable energy production and the coupling of different energy sectors such as heating, cooling and electricity have significantly increased the complexity of urban energy systems. Such multi-energy systems (MES) can be operated more efficiently with the aid of optimization-based energy management systems (EMS). However, most existing EMS are tailor-made for one specific system or class of systems, i.e. are not generally applicable. Furthermore, only limited information on the actual savings potential of the usage of an EMS under realistic conditions is available. Therefore, this paper presents a novel modular modeling approach for an EMS for urban MES, which also enables the modeling of complex system configurations. To assess the actual savings potential of the proposed EMS, a comprehensive case study was carried out. In the course of this the influence of different user behavior, changing climatic conditions and forecast errors on the savings potential was analyzed by comparing it with a conventional control strategy. The results showed that using the proposed EMS in conjunction with supplementary system components (thermal energy storage and battery) an annual cost savings potential of between 3 and 6% could be achieved.


Conference contributions | 2020

A modular energy management system for multi-energy systems

Muschick D, Kaisermayer V, Moser A, Gölles M. A modular energy management system for multi-energy systems. 6th Central European Biomass Conference, 22-24 January 2020, Graz.

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Scientific Journals | 2020

A novel production route and process optimization of biomass-derived paraffin wax for pharmaceutical application

Gruber H, Lindner L, Arlt S, Reichhold A, Rauch R, Weber G, Trimbach J, Hofbauer H. A novel production route and process optimization of biomass-derived paraffin wax for pharmaceutical application. Journal of Cleaner Production. 2020;275:124135

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The Biomass to Liquid (BtL) Fischer-Tropsch (FT) route converts lignocellulosic feedstock to renewable hydrocarbons. This, paper shows a novel production route for biomass-derived synthetic paraffin wax via gasification of lignocellulosic feedstock, Fischer-Tropsch synthesis (FTS) and hydrofining. The Fischer-Tropsch wax was fractionated, refined and analyzed with respect to compliance to commercial standards. The fractioned paraffin waxes were hydrofined using a commercial sulfide NiMo–Al2O3 catalyst and a trickle bed reactor. A parametric variation was performed to optimize the hydrofining process. It was shown that the produced medium-melt paraffin wax could fulfill the requirements for “Paraffinum solidum” defined by the European Pharmacopoeia (Ph. Eur). The high-melt wax fraction showed potential to be used as food packaging additive. Furthermore, the renewable wax was analyzed regarding PAH content and it was shown that the hydrofined wax was quasi-PAH-free.


Conference contributions | 2020

Advanced biomass CCHP (BIO-CCHP) based on gasification, SOFC and cooling machines

Lagler J, Martini S. Advanced biomass CCHP (BIO-CCHP) based on gasification, SOFC and cooling machines. 6th Central European Biomass Conferenc, 2020, Graz.

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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.

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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.

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