TY - JOUR A1 - Conti, Fosca A1 - Saidi, Abdessamad A1 - Goldbrunner, Markus T1 - Evaluation Criteria and Benefit Analysis of Mixing Process in Anaerobic Digesters of Biogas Plants JF - Environmental and Climate Technologies N2 - A valid method to evaluate decisions of a project proposal is the so-called cost-benefit analysis. Criteria are selected and properly weighted to determine if the project is effective and feasible. The present research study is focused on methodical selection of design parameters to install two propeller mixers inside anaerobic digesters of biogas plants. A cylindrical tank of 1400 m3 was considered. For the model-based optimisation, the substrate was considered as a non-Newtonian fluid with a density of 1090 kg/m3. The Oswald-de Waele power-law model was selected to account for the rheological behaviour of the fluid. Installation parameters of the mixers were rotational angles and heights of the shafts of the two propellers. A computational model was developed to simulate the fluid dynamics depending on the mixing process inside the tank. Several configurations were analysed according to evaluating criteria such as the value of the fluid velocity, its distribution along the three spatial dimensions, and the power consumption to rotate the mixers. The maximum fluid velocity and minimum power consumption were observed when the propellers are located at intermediate height inside the tank and with the shafts perpendicular to the tank radius. With this configuration, the fluid reaches a maximum velocity of 0.28 m/s. According to the investigation, it is evident that mixing systems with propeller shafts deep-seated and parallel to the tank radius should be avoided, both in term of efficiency of the fluid mixing distribution and in term of power consumption. UR - https://doi.org/10.2478/rtuect-2020-0105 KW - Anaerobic digester KW - biomass KW - computational fluid dynamics (CFD) KW - Cost-Benefit Analysis (CBA) KW - evaluation criteria KW - flow velocity KW - full scale biogas digester KW - mixing KW - propeller Y1 - 2020 UR - https://doi.org/10.2478/rtuect-2020-0105 UR - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:573-9274 SN - 2255-8837 VL - 24 IS - 3 SP - 305 EP - 317 PB - De Gruyter Poland CY - Warsaw ER - TY - JOUR A1 - Conti, Fosca A1 - Saidi, Abdessamad A1 - Goldbrunner, Markus T1 - Numeric Simulation-Based Analysis of the Mixing Process in Anaerobic Digesters of Biogas Plants JF - Chemical Engineering & Technology N2 - Stirring systems with two rotational three-bladed propellers were analyzed using computational fluid dynamics. The propellers are located at three heights and seven angles in a tank with 9 m radius. The fluid was characterized by non-Newtonian rheology and simulated by applying the k-ε turbulence model and the standard k-ω model. Reynolds numbers were estimated. High fluid speeds were obtained with the propellers located at a height of 2 m and oriented at 90° with respect to the tank radius. In the top regions of the tank, the fluid velocity was generally less intense and less affected by the angle setting. The configurations identified as good mixing systems showed power consumptions broadly distributed around 30 kW. UR - https://doi.org/10.1002/ceat.201900650 KW - Anaerobic digester KW - Biogas plant KW - Biomass KW - Fluid dynamics KW - Mixing Y1 - 2020 UR - https://doi.org/10.1002/ceat.201900650 UR - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:573-9379 SN - 1521-4125 VL - 43 IS - 8 SP - 1522 EP - 1529 PB - Wiley CY - Weinheim ER - TY - JOUR A1 - Bär, Katharina A1 - Wageneder, Stefanie A1 - Solka, Felix A1 - Saidi, Abdessamad A1 - Zörner, Wilfried T1 - Flexibility Potential of Photovoltaic Power Plant and Biogas Plant Hybrid Systems in the Distribution Grid JF - Chemical Engineering & Technology N2 - The potential of combining biogas and photovoltaic (PV) power plants in hybrid systems in the German distribution grid is analyzed. The focus of the present research is on balancing the intermittent power supply from PV power plants with the controllable power production of combined heat and power (CHP) units of biogas plants within a period of seconds. To achieve an increase of the total energy feed-in of biogas and PV power plants to the electricity grid, a biogas plant energy management system is described. System parameters, such as the variable feed-in of PV power plants or power ramps of the start-up process of controllable biogas plant CHP unit, are described and adapted to the global installed capacity of PV power plant and biogas plants in the German distribution grid. UR - https://doi.org/10.1002/ceat.202000025 KW - Biogas KW - Combined heat and power units KW - Distribution grid KW - Flexible electricity production KW - Photovoltaic power plants Y1 - 2020 UR - https://doi.org/10.1002/ceat.202000025 UR - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:573-9380 SN - 1521-4125 VL - 43 IS - 8 SP - 1571 EP - 1577 PB - Wiley CY - Weinheim ER - TY - JOUR A1 - Conti, Fosca A1 - Saidi, Abdessamad A1 - Goldbrunner, Markus T1 - CFD Modelling of Biomass Mixing in Anaerobic Digesters of Biogas Plants JF - Environmental and Climate Technologies N2 - Cut in greenhouse gas emissions, increment of energy from renewables and improvement in energy efficiency represent the three key targets for future energy systems. Among the available bioenergy technologies, biogas production via biodegradation and anaerobic digestion is a widely applied approach, not only to produce biofuels but also to manage industrial and domestic organic waste. Within the biogas production, a sufficient mixing of the organic mass is a crucial step to ensure high biogas yields by bacteria and enzymes. Measurements of the electric power consumption of biogas plants revealed that the electrical energy demand of the stirrer system has a high share of the total electricity consumption of a biogas plant. Investigations on real biogas digesters to optimize the mixing process are cost and time intensive. Therefore, laboratory prototypes and computational simulations represent promising alternatives to analyse and improve the efficiency of mixing systems. In this paper, a computational fluid dynamics (CFD) model is presented, which is applied to commercial stirring systems. The case of two propeller stirrers, located in diametrically opposite positions in a tank filled with ca. 1400 m3 of substrate is described in detail. For the simulation, the rheology of the fluid is adapted to a biomass with 12 wt % dry matter content and obeying the non-Newtonian generalized Ostwald-de Waele power law. The developed simulation procedure considers the rotation angle of each propeller and its height. A total of 441 mixing configurations are calculated and evaluated in terms of the technical benefit. The investigation reveals that locations of the rotors far away from the bottom and high rotational angles cause advantageous fluid dynamics. UR - https://doi.org/10.2478/rtuect-2019-0079 KW - Anaerobic digester KW - biomass KW - cellulose KW - computational fluid dynamics (CFD) KW - full scale biogas digester KW - laboratory digester KW - mixing KW - rheology KW - viscosity Y1 - 2019 UR - https://doi.org/10.2478/rtuect-2019-0079 UR - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:573-9544 SN - 2255-8837 VL - 23 IS - 3 SP - 57 EP - 69 PB - RTU Press CY - Riga ER - TY - CHAP A1 - Grösch, Norbert A1 - Vogt, Regine A1 - Saidi, Abdessamad A1 - Zörner, Wilfried T1 - Repoweringmaßnahmen hinsichtlich zukünftiger Aufgaben von Biogasanlagen BT - Ergebnisse aus dem Projekt REzAB T2 - Schriftenreihe Umweltingenieurwesen Agrar- und Umweltwissenschaftliche Fakultät, Band 95, Tagungsband 14. Rostocker Bioenergieforum / 19. DIALOG Abfallwirtschaft MV UR - https://doi.org/10.18453/rosdok_id00002650 KW - Biogas KW - Repowering KW - Konzepte KW - Bestandsanlagen KW - Weiterbetrieb Y1 - 2020 UR - https://doi.org/10.18453/rosdok_id00002650 SN - 978-3-86009-507-2 SP - 133 EP - 142 PB - Universität Rostock, Agrar- und Umweltwissenschaftliche Fakultät CY - Rostock ER - TY - CHAP A1 - Stark, Matthias A1 - Saidi, Abdessamad A1 - Zörner, Wilfried T1 - KomBio-Speicher: Entwicklung eines neuartigen Dampfspeichersystems für ein flexibles Biomasse-Heizkraftwerk zur Erhöhung der Systemstabilität T2 - Schriftenreihe Umweltingenieurwesen Agrar- und Umweltwissenschaftliche Fakultät, Band 95, Tagungsband 14. Rostocker Bioenergieforum / 19. DIALOG Abfallwirtschaft MV UR - https://doi.org/10.18453/rosdok_id00002650 Y1 - 2020 UR - https://doi.org/10.18453/rosdok_id00002650 SN - 978-3-86009-507-2 SP - 345 EP - 354 PB - Universität Rostock CY - Rostock ER - TY - CHAP A1 - Wageneder, Stefanie A1 - Grösch, Norbert A1 - Saidi, Abdessamad A1 - Wagner, Robert A1 - Glötzl, Melanie A1 - Gleich, Jasmin A1 - Hermann, Christiane A1 - Mielke, Sophie A1 - Freydank, Christian A1 - Zörner, Wilfried T1 - Lösungsansätze zur technischen Anpassung bestehender Biogasanlagen für die Nutzung faseriger Reststoffe BT - Auswahl der zu untersuchenden Anlagen im Rahmen des Projekts „LaRA“ T2 - Schriftenreihe Umweltingenieurwesen Agrar- und Umweltwissenschaftliche Fakultät, Band 95, Tagungsband 14. Rostocker Bioenergieforum / 19. DIALOG Abfallwirtschaft MV UR - https://doi.org/10.18453/rosdok_id00002650 Y1 - 2020 UR - https://doi.org/10.18453/rosdok_id00002650 SN - 978-3-86009-507-2 SP - 409 EP - 414 PB - Universität Rostock, Agrar- und Umweltwissenschaftliche Fakultät CY - Rostock ER - TY - CHAP A1 - Yadav, Akhilesh A1 - Sinha, Anuj A1 - Saidi, Abdessamad A1 - Trinkl, Christoph A1 - Zörner, Wilfried T1 - NILM based energy disaggregation algorithm for dairy farms T2 - NILM'20: Proceedings of the 5th International Workshop on Non-Intrusive Load Monitoring UR - https://doi.org/10.1145/3427771.3427846 KW - NILM KW - energy disaggregation KW - smart meter KW - dairy farms KW - deep neural networks Y1 - 2020 UR - https://doi.org/10.1145/3427771.3427846 SN - 978-1-4503-8191-8 SP - 16 EP - 19 PB - ACM CY - New York ER - TY - JOUR A1 - Bär, Katharina A1 - Saidi, Abdessamad A1 - Hackl, Christoph A1 - Zörner, Wilfried T1 - Combined operation of photovoltaic and biogas plants for optimal transformer loading JF - Chemical Engineering Transactions UR - https://doi.org/10.3303/CET1976101 Y1 - 2019 UR - https://doi.org/10.3303/CET1976101 SN - 978-88-95608-73-0 SN - 2283-9216 VL - 2019 IS - 76 SP - 601 EP - 606 PB - AIDIC The Italian Association of Chemical Engineering CY - Milano ER - TY - JOUR A1 - Stark, Matthias A1 - Conti, Fosca A1 - Saidi, Abdessamad A1 - Zörner, Wilfried A1 - Greenough, Richard T1 - Steam storage systems for flexible biomass CHP plants BT - evaluation and initial model based calculation JF - Biomass and Bioenergy UR - https://doi.org/10.1016/j.biombioe.2019.105321 KW - CHP KW - solid biomass KW - steam storage KW - high temperature storage KW - flexible power generation Y1 - 2019 UR - https://doi.org/10.1016/j.biombioe.2019.105321 SN - 0961-9534 VL - 2019 IS - 128 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Stark, Matthias A1 - Philipp, Matthias A1 - Saidi, Abdessamad A1 - Trinkl, Christoph A1 - Zörner, Wilfried A1 - Greenough, Richard T1 - Design parameters of steam accumulators for the utilization in industrial solid biomass-fuelled CHP plants JF - Chemical Engineering Transactions UR - https://doi.org/10.3303/CET1976137 Y1 - 2019 UR - https://doi.org/10.3303/CET1976137 SN - 978-88-95608-73-0 SN - 2283-9216 VL - 2019 IS - 76 SP - 817 EP - 822 PB - AIDIC The Italian Association of Chemical Engineering CY - Milano ER - TY - CHAP A1 - Saidi, Abdessamad A1 - Conti, Fosca A1 - Karl, Jürgen A1 - Goldbrunner, Markus ED - Thrän, Daniela ED - Pfeiffer, Diana T1 - Biogastankstelle für die Landwirtschaft – Gegenüberstellende ökonomische Bewertung unterschiedlicher Verfahren für die dezentrale partielle Biogasaufbereitung T2 - 8. Statuskonferenz Bioenergie Reader Y1 - 2019 UR - https://www.energetische-biomassenutzung.de/veranstaltungen/statuskonferenzen/8-statuskonferenz/programm SN - 978-3-946629-27-6 SN - 2698-6809 SP - 78 EP - 79 PB - DBFZ Deutsches Biomasseforschungszentrum gemeinnützige GmbH CY - Leipzig ER - TY - CHAP A1 - Conti, Fosca A1 - Saidi, Abdessamad A1 - Goldbrunner, Markus ED - Thrän, Daniela ED - Pfeiffer, Diana T1 - Verbesserung der Durchmischung in Biogasfermentern T2 - 8. Statuskonferenz Bioenergie Reader Y1 - 2019 UR - https://www.energetische-biomassenutzung.de/veranstaltungen/statuskonferenzen/8-statuskonferenz/programm SN - 978-3-946629-27-6 SN - 2698-6809 SP - 105 PB - DBFZ Deutsches Biomasseforschungszentrum gemeinnützige GmbH CY - Leipzig ER - TY - JOUR A1 - Wiedemann, Leonhard A1 - Conti, Fosca A1 - Saidi, Abdessamad A1 - Sonnleitner, Matthias A1 - Goldbrunner, Markus T1 - Modeling Mixing in Anaerobic Digesters with Computational Fluid Dynamics Validated by Experiments JF - Chemical Engineering & Technology UR - https://doi.org/10.1002/ceat.201800083 KW - Anaerobic digesters KW - Biomass KW - Computational fluid dynamics KW - Mixing KW - Rheology Y1 - 2018 UR - https://doi.org/10.1002/ceat.201800083 SN - 1521-4125 VL - 41 IS - 11 SP - 2101 EP - 2110 PB - Wiley CY - Weinheim ER - TY - CHAP A1 - Conti, Fosca A1 - Wiedemann, Leonhard A1 - Saidi, Abdessamad A1 - Sonnleitner, Matthias A1 - Goldbrunner, Markus T1 - Mixing of a Model Substrate in a Scale-down Laboratory Digester and Processing with a Computational Fluid Dynamics Model T2 - EUBCE 2018 Online Conference Proceedings UR - https://doi.org/10.5071/26thEUBCE2018-2CV.5.34 KW - anaerobic digestion KW - biomass KW - cellulose KW - laboratory digester KW - mixing process KW - fluid dynamic Y1 - 2018 UR - https://doi.org/10.5071/26thEUBCE2018-2CV.5.34 SN - 978-88-89407-18-9 SN - 2282-5819 SP - 811 EP - 815 PB - ETA s.r.l. CY - Florenz ER - TY - JOUR A1 - Conti, Fosca A1 - Wiedemann, Leonhard A1 - Sonnleitner, Matthias A1 - Saidi, Abdessamad A1 - Goldbrunner, Markus T1 - Monitoring the mixing of an artificial model substrate in a scale-down laboratory digester JF - Renewable Energy UR - https://doi.org/10.1016/j.renene.2018.08.013 KW - Laboratory digester KW - Anaerobic digestion KW - Artificial chemical substrate KW - Mixing KW - Particle image velocimetry (PIV) KW - Acoustic Doppler velocimetry (ADV) Computational fluid dynamics (CFD) Y1 - 2018 UR - https://doi.org/10.1016/j.renene.2018.08.013 SN - 0960-1481 VL - 2019 IS - 132 SP - 351 EP - 362 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Saidi, Abdessamad A1 - Trinkl, Christoph A1 - Conti, Fosca A1 - Goldbrunner, Markus A1 - Karl, Jürgen T1 - Partially Upgraded Biogas: Potential forDecentralized Utilization in AgriculturalMachinery JF - Chemical Engineering & Technology UR - https://doi.org/10.1002/ceat.201800100 KW - Agriculture KW - Biogas KW - Combustion KW - Fuel KW - Upgrading Y1 - 2018 UR - https://doi.org/10.1002/ceat.201800100 SN - 1521-4125 VL - 41 IS - 11 SP - 2111 EP - 2119 PB - Wiley-VCH CY - Weinheim ER - TY - JOUR A1 - Saidi, Abdessamad A1 - Conti, Fosca A1 - Sonnleitner, Matthias A1 - Goldbrunner, Markus T1 - Membrane separation process for small scaled partial biogas upgrading JF - IOP Conference Series: Materials Science and Engineering N2 - Biogas upgrading is actually limited to the production of biomethane as natural gas substitute. To realize the according gas quality a cost intensive methane enrichment is required, wherefore biogas upgrading is actually merely cost-efficient in case of high production rates. Since the energy and cost effort disproportionately increases with the required product gas purity partial biogas upgrading for decentralized utilization represents a promising utilization approach for farm based applications. Among the available technologies for CO2-separation the gas permeable membrane has high potential for small scaled biogas upgrading. Within the present study a model based analysis to determine the savings potential of a membrane based upgrading system is performed. UR - https://doi.org/10.1088/1757-899X/446/1/012012 Y1 - 2018 UR - https://doi.org/10.1088/1757-899X/446/1/012012 UR - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:573-28012 SN - 1757-899X VL - 2018 IS - 446 PB - IOP Publishing CY - London ER - TY - JOUR A1 - Conti, Fosca A1 - Wiedemann, Leonhard A1 - Saidi, Abdessamad A1 - Goldbrunner, Markus T1 - Effect of mixing of waste biomass in anaerobic digesters for production of biogas JF - IOP Conference Series: Materials Science and Engineering N2 - Biogas technology is an important renewable bioenergy producer. The biogas generating process needs to be optimized to minimise the energy consumption due to the stirring of biomass slurry. Numerical simulations and laboratory experiments are economically and practically preferred over investigations of industrial scale biogas plants. Additionally, a strategic approach to model the reality in scientific laboratories is to use a rheological valid artificial chemical substrate to replace real biomass. The proposes of this study were (i) to investigate the mixing process in a 1:12 scaled-down home-made laboratory digester filled with a 0.3 wt% water-cellulose solution, (ii) to simulate the mixing process in the laboratory-scale digester using a computational fluid dynamics model, (iii) to validate the model by comparison of the simulation with laboratory experiments results obtained on the laboratory digester. Optical and acoustic measurements on the flow velocity inside the digester during the mixing process of the water-cellulose solutions indicate that the model based on computational fluid dynamics is valid. The data are presented and discussed in the paper. UR - https://doi.org/10.1088/1757-899X/446/1/012011 Y1 - 2018 UR - https://doi.org/10.1088/1757-899X/446/1/012011 UR - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:573-28021 SN - 1757-899X VL - 2018 IS - 446 PB - IOP Publishing CY - London ER -