FG Thermische Energietechnik
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BTU
Druckelektrolyse zur Wasserstoffherstellung- eine Kurzübersicht zu energetischen Vor- und Nachteilen
(2015)
At first I was wondering what the structure of an article about pressurized steam fluidized bed drying could look like. After some thought, I knew that it should be divided into two parts. In order to highlight the creative and inventive spirit of former engineers, as well as their struggle to increase the efficiency of drying machines, a historical outline of the drying technology in general and the concept of steam fluidized bed drying in particular will form the first part of the article. The second part will present the practical and research contribution of Prof. Krautz and his colleagues to the advancement of this field. The article as a whole will be able to provide an overview of the coal/lignite drying, with focus on the pressurized steam fluidized bed drying principle implemented in the Lusatian mining area.
Mit der steigenden Erzeugung volatilen Stroms aus erneuerbaren Energien werden die Anforderungen an die Flexibilität der konventionellen Kraftwerke erhöht. Der Einsatz von Stützfeuerungssystemen auf Basis von Trockenbraunkohle (TBK) ermöglicht die Erweiterung des Lastbereiches und der Lastgradienten am Dampferzeuger. Untersuchungen zum Teillastverhalten von TBK-Brennern wurden an der BTU Cottbus – Senftenberg an einem 400 kWth Verbrennungsversuchstand und an dem industriellen 30 MWth TBK-Staubbrenner der Firma BBS (Babcock Borsig Steinmüller GmbH) durchgeführt. Der verfügbare Einsatzbereich des Brenners ist maßgeblich von der Intensität den brennernahen Mischungsvorgang abhängig. Mit der Absenkung der Brennerleistung ist beispielsweise eine signifikante Steigerung der NOx-Emission verbunden. Dieser Effekt ist auf die Veränderung des brennernahen Strömungsprofiles zurückzuführen. Mit Maßnahmen wie der Erhöhung der Drallzahl, Verteilung der Luftimpulsströme und Veränderung des Primärimpulses konnte eine Stabilisierung und Intensivierung der Reaktionszone und somit eine Verbesserte des Teillastverhaltens nachgewiesen werden.
1.
To increase the efficiency of PEM electrolysis, simulation models are required that accurately describe the system's electrochemical and thermal behavior in a computationally efficient manner and are thus suitable for developing control strategies. Therefore, a pseudo-2D PEM electrolyzer model is presented in this paper, which is a compromise between the previously developed models regarding their model complexity. The electrochemical behavior is described with equations commonly used in the literature and the thermal behavior with correlations for gas-liquid heat transfer. Preliminary validation indicates that the model can describe the electrochemical behavior and thermal dynamics of a PEM electrolysis stack with good accuracy.
Renewable energy sources are becoming a greater component of the electrical mix, while being significantly more volatile than conventional energy sources. As a result, net stability and availability pose significant challenges. Energy-intensive processes, such as chlor-alkali electrolysis, can potentially adjust their consumption to the available power, which is known as demand side management or demand response. In this study, a dynamic model of a chlor-alkali membrane cell is developed to assess the flexible potential of the membrane cell. Several improvements to previously published models were made, making the model more representative of state-of-the-art CA plants. By coupling the model with a wind power profile, the current and potential level over the course of a day was simulated. The simulation results show that the required ramp rates are within the regular operating possibilities of the plant for most of the time and that the electrolyte concentrations in the cell can be kept at the right level by varying inlet flows and concentrations. This means that a CA plant can indeed be flexibly operated in the future energy system.