@misc{LechnerMerzschKrautz, author = {Lechner, Stefan and Merzsch, Matthias and Krautz, Hans Joachim}, title = {Heat-transfer from horizontal tube bundles into fluidized beds with Geldart A lignite particles}, series = {Powder Technology}, journal = {Powder Technology}, number = {253}, doi = {10.1016/j.powtec.2013.10.041}, pages = {14 -- 21}, abstract = {This work investigates the heat transfer mechanism in fluidized beds equipped with horizontal heat exchanger surfaces such as single tubes and especially tube bundles. Previous works were performed for varying operating conditions and solids' material properties, leading to a heterogeneous and therefore not applicable spectrum of derived correlations for the influence of tube diameter and tube bundle geometry on heat transfer. Based on a wide range validation of the correlation for the influence of single tube diameter on heat transfer coefficient, tube bundles with different tube diameters and horizontal and vertical spacings and alignments were investigated. Experiments were carried out using electrical heat transfer probes in a 0.15 m2 fluidized bed test facility at ambient conditions. Geldart A lignite and Geldart D solids were used in order to distinguish between predominant particle-convective and gas-convective heat transfer mechanisms. The tube bundle reduction factor on heat transfer coefficient was derived as a key parameter based on dimensionless geometric numbers. This factor predicts the reduction of the heat transfer coefficient compared to that of the single tube due to the particle and gas flow disturbances caused by the immersed tubes. Tube diameter as well as tube bundle geometry were successfully implemented into useful correlations for predicting tube bundles' heat transfer of gas-solid fluidized bed systems operating with fine particles.}, language = {en} } @inproceedings{ZiemsTillmannKrautz, author = {Ziems, Christian and Tillmann, Christine and Krautz, Hans Joachim}, title = {H2-Forschung an der BTU Cottbus}, series = {4. Energiefachtagung, Cottbus, 2012}, booktitle = {4. Energiefachtagung, Cottbus, 2012}, language = {de} } @phdthesis{Hoehne, author = {H{\"o}hne, Olaf}, title = {Grundlagenuntersuchungen zum Einfluss des Systemdrucks auf die Trocknung von Braunkohle in Wasserdampf}, publisher = {Cuvillier}, address = {G{\"o}ttingen}, isbn = {978-3-9540407-6-6}, pages = {XV, 141}, language = {de} } @inproceedings{ZiemsTannertKrautz, author = {Ziems, Christian and Tannert, Daniel and Krautz, Hans Joachim}, title = {Grundlagenforschung zur Optimierung des alkalischen Druckelektrolyseprozesses am 25 bar Einzel-Zell-Versuchsstand - Projektvorstellung}, series = {19. Symposium - Nutzung regenerativer Energiequellen und Wasserstofftechnik, 8. - 10. November 2012 Stralsund}, booktitle = {19. Symposium - Nutzung regenerativer Energiequellen und Wasserstofftechnik, 8. - 10. November 2012 Stralsund}, publisher = {Fachhochschule}, address = {Stralsund}, isbn = {978-3-9813334-5-9}, language = {de} } @inproceedings{ZiemsKrautz, author = {Ziems, Christian and Krautz, Hans Joachim}, title = {Grid integration of renewable energies and hydrogen research at BTU Cottbus}, series = {Dena Konferenz "Power to Gas - innovative Systeml{\"o}sungen f{\"u}r ein zukunftsf{\"a}higes Energiesystem entwickeln", Berlin, 2012}, booktitle = {Dena Konferenz "Power to Gas - innovative Systeml{\"o}sungen f{\"u}r ein zukunftsf{\"a}higes Energiesystem entwickeln", Berlin, 2012}, language = {en} } @article{KalinaLoefflerKrautzetal., author = {Kalina, Hartmut and L{\"o}ffler, Steffen and Krautz, Hans Joachim and M{\"o}ller, J.}, title = {Gesamtbewertung f{\"u}r erneuerbare Energien m{\"o}glich und sinnvoll}, language = {de} } @misc{HorsfieldScheckWenderothKrautzetal., author = {Horsfield, B. and Scheck-Wenderoth, Magdalena and Krautz, Hans Joachim and Mutti, M.}, title = {Geoenergy: From visions to solutions}, doi = {http://dx.doi.org/10.1016/j.chemer.2010.06.002}, language = {en} } @inproceedings{MenkeKlattKrautzetal., author = {Menke, Dominik and Klatt, Matthias and Krautz, Hans Joachim and Gade, Udo and Mandel, Hans}, title = {Gemeinsame Analyse der Prozesstechnik und Verf{\"u}gbarkeit moderner Großkraftwerke}, language = {de} } @inproceedings{KlattWarnecke, author = {Klatt, Matthias and Warnecke, Martin}, title = {Gedanken zur Instandhaltungsperiodenbestimmung mit generischen Algorithmen}, language = {de} } @phdthesis{Tappe, author = {Tappe, Stephanie}, title = {Gaspotentiometrische und thermogravimetrische Abbranduntersuchungen vom Braun- und Steinkohlen in Luft und in O2/CO2-Atmosph{\"a}ren}, publisher = {Aachen : Shaker}, isbn = {978-3-8440-0290-4}, language = {de} } @inproceedings{TappeKrautz, author = {Tappe, Stephanie and Krautz, Hans Joachim}, title = {Gaspotentiometrische Abbranduntersuchungen verschiedener Kohlen in Luft- und O2/CO2-Atmosph{\"a}ren}, language = {de} } @inproceedings{KrautzGuerreroAmezcuaZiems, author = {Krautz, Hans Joachim and Guerrero Amezcua, Cinthya Larissa and Ziems, Christian}, title = {Future Developments of the Photovoltaic Technologies in germany and their Consequences in the Power Network stability, the System security and the demand of chemical long-term storage}, series = {SASEC 2015, Third Southern African Solar Energy Conference, 11 - 13 May 2015, Kruger National Park, South Africa}, booktitle = {SASEC 2015, Third Southern African Solar Energy Conference, 11 - 13 May 2015, Kruger National Park, South Africa}, pages = {383 -- 388}, language = {en} } @inproceedings{LoefflerKrautz, author = {L{\"o}ffler, Steffen and Krautz, Hans Joachim}, title = {Fortschrittliche Verbrennungstechniken f{\"u}r dezentrale Energieanlagen}, abstract = {Vortrag auf VIK-Arbeitskreis "Energietechnische Zukunftskonzepte", G{\"o}rlitz}, language = {de} } @inproceedings{KrautzThielenGriebeetal., author = {Krautz, Hans Joachim and Thielen, W. and Griebe, Steffen and Paulick, G.}, title = {Fortschrittliche Braunkohleverbrennungstechniken f{\"u}r dezentrale Energieanlagen}, series = {Fortschrittliche Braunkohlenutzung im liberalisierten Strommarkt, Tagung Cottbus, 23. und 24. Februar 1999}, booktitle = {Fortschrittliche Braunkohlenutzung im liberalisierten Strommarkt, Tagung Cottbus, 23. und 24. Februar 1999}, publisher = {VDI-Verlag}, address = {D{\"u}sseldorf}, isbn = {3-18-091456-4}, pages = {187 -- 208}, language = {de} } @misc{KrautzNimtz, author = {Krautz, Hans Joachim and Nimtz, Michael}, title = {Flexible Operation of CCS Power Plants to Match Variable Renewable Energies}, series = {Energy Procedia}, volume = {2013}, journal = {Energy Procedia}, number = {40}, issn = {1876-6102}, doi = {10.1016/j.egypro.2013.08.034}, pages = {294 -- 303}, abstract = {The German Energiewende is resulting in high grid load changes caused by renewable energies. Therefore flexibility of power plants is getting more and more important. Future CCS power plants are usually equipped with more components than conventional power plants, resulting in a more complex and inert reaction on changes in power output. Additionally, due to the change in price structures and higher fixed and operational costs for CCS power plants, it is harder for them to be economically efficient. This study will show different options to increase the flexibility of CCS power plants and evaluate their benefits.}, language = {en} } @misc{KrautzCorreadaSilvaKangwanpongpan, author = {Krautz, Hans Joachim and Corr{\^e}a da Silva, Rodrigo and Kangwanpongpan, Tanin}, title = {Flame pattern, temperatures and stability limits of pulverized oxy-coal combustion}, series = {Fuel : the science and technology of fuel and energy}, journal = {Fuel : the science and technology of fuel and energy}, number = {Vol. 115}, issn = {0016-2361}, doi = {10.1016/j.fuel.2013.07.049}, pages = {507 -- 520}, abstract = {The challenges in maintaining a stable oxy-coal flame have been reported in the open literature. In case of pulverized coal combustion, narrower flammable regimes arise not only of differences in the feed gas composition, but also due to changes in the flow dynamics because of reduced volume flow rate through the burners to match similar temperatures and radiative heat transfer within the furnace. The present work focuses on the study of flame structure and stability of pre-dried lignite fired by a staged feed-gas burner. Experimental runs were carried out in a 0.40 MWth laboratory facility, with the objective of investigating the effects of swirl strength and feed gas distribution in the burner registers. To assess the experimental data, a numerical study of the non-reacting flow in the near burner region is performed. Predicted flow pattern and flame images show that the primary fuel jet penetrates the internal recirculation zone, forming an annular doughnut reverse flow region for both firing conditions and resembling a type-1 flame pattern. Temperature measurements indicate that the feed gas distribution among the burner registers control the flame temperature in parallel with the swirl number in both air-fired and oxy-fired environments. The oxy-fuel cases exhibite markedly reduced temperatures on the flame axis. This difference in the core arises not just from the more pronounced penetration depth of the primary jet, but also due to reaction mechanisms including pyrolysis and gasification reactions at the higher concentrations of CO2 and water vapor. Flame stabilization is shown to be strongly dependent on an appropriate distribution of the feed gas and strength of swirling flow in the burner front. The results correlated in terms of swirl number, secondary/tertiary flow ratio and secondary/primary axial momentum point to similarities in the stability limits between air-firing and oxy-firing.}, language = {en} } @inproceedings{ZiemsTannertKrautz, author = {Ziems, Christian and Tannert, Daniel and Krautz, Hans Joachim}, title = {First modeling results of an advanced pressurized alkaline electrolyzer for hydrogen production}, series = {19. World Hydrogen Energy Conference, Toronto, 2012}, booktitle = {19. World Hydrogen Energy Conference, Toronto, 2012}, language = {en} } @misc{AbangLiskKrautz, author = {Abang, Roger Atini and Lisk, Alexander and Krautz, Hans Joachim}, title = {Fireside corrosion of superheater materials under oxy-coal firing conditions}, series = {Energy Procedia}, volume = {40}, journal = {Energy Procedia}, issn = {1876-6102}, doi = {10.1016/j.egypro.2013.08.035}, pages = {304 -- 311}, abstract = {The present study investigates the fireside corrosion behavior of selected superheater materials, namely: T24, P92, VM12-SHC, A800HT, and 7RE10 under oxy-coal combustion atmospheres. Data on mass change, scale thickness, metal loss, surface morphology and micro-structural characteristics of corrosion products were obtained. The alloy specimens were analyzed by SEM-EDX, light microscopy and X-Ray diffraction techniques. The results after 2000 hours of exposure at a metal surface temperature of 600 °C indicate that metal wastage increased with decreasing Cr-content under oxy-coal conditions.}, language = {en} } @inproceedings{AhaKochKrautz, author = {Aha, Ulrich and Koch, Alexander and Krautz, Hans Joachim}, title = {Finding the optimal power plant maintenance strategy with fuzzy input data}, series = {11th International Probabilistic Safety Assessment and Management Conference and the Annual European Safety and Reliability Conference 2012, (PSAM11 ESREL 2012), Helsinki, Finland 25 - 29 June 2012, Vol. 1}, booktitle = {11th International Probabilistic Safety Assessment and Management Conference and the Annual European Safety and Reliability Conference 2012, (PSAM11 ESREL 2012), Helsinki, Finland 25 - 29 June 2012, Vol. 1}, publisher = {IAPSAM \& ESRA}, address = {Red Hook, NY}, isbn = {978-1-62276-436-5}, pages = {341 -- 347}, language = {en} } @inproceedings{KatzerKlattLisketal., author = {Katzer, Christian and Klatt, Matthias and Lisk, Alexander and Krautz, Hans Joachim}, title = {Experimentelle Untersuchungen zur Entwicklung eines elektrisch z{\"u}ndenden Kohlestaubbrenners}, series = {Kraftwerkstechnik 2015, Strategien, Anlagentechnik und Betrieb, Beitr{\"a}ge des 47. Kraftwerkstechnischen Kolloquiums vom 13. und 14. Oktober 2015 in Dresden}, booktitle = {Kraftwerkstechnik 2015, Strategien, Anlagentechnik und Betrieb, Beitr{\"a}ge des 47. Kraftwerkstechnischen Kolloquiums vom 13. und 14. Oktober 2015 in Dresden}, publisher = {SAXONIA}, address = {Freiberg}, isbn = {978-3-934409-70-5}, pages = {279 -- 288}, language = {de} }