TY - THES A1 - Schreiber, Matthias T1 - Modellierung von Hydrodynamik und Wärmeübertragung in blasenbildenden Wirbelschichten zur Trocknung von Braunkohle Y1 - 2013 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:co1-opus-27263 UR - http://opus.kobv.de/btu/volltexte/2013/2726/ ER - TY - THES A1 - Lechner, Stefan T1 - Untersuchungen zur Berechnung und Optimierung des Wärmeübergangs bei der Dampfwirbelschicht-Trocknung am Beispiel von Lausitzer Braunkohlen Y1 - 2012 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:co1-opus-27120 UR - http://opus.kobv.de/btu/volltexte/2012/2712/ ER - TY - CHAP A1 - Wiese, Bernd A1 - Nimtz, Michael A1 - Möller, Fabian A1 - Otto, Christopher A1 - Liebscher, Axel A1 - Schmidt-Hattenberger, Cornelia T1 - Determination of thermodynamics in a CO2 injection well using pressure and distributed temperature sensing T2 - Models – repositories of knowledge, proceedings of Model CARE2011 held in Leipzig, Germany, September 2011 Y1 - 2012 SN - 978-1-907161-34-6 SP - 286 EP - 290 PB - IAHS Publication CY - Wallingford ER - TY - THES A1 - Höhne, Olaf T1 - Grundlagenuntersuchungen zum Einfluss des Systemdrucks auf die Trocknung von Braunkohle in Wasserdampf Y1 - 2012 UR - http://www.cuvillier.de/flycms/de/html/30/-UickI3zKPS3wdUg=/Buchdetails.html SN - 978-3-9540407-6-6 PB - Cuvillier CY - Göttingen ER - TY - CHAP A1 - Wiedemann, Philipp A1 - Krautz, Hans Joachim T1 - Numerical study of gas–solid fluidized beds: Analysis of pressure fluctuations for detection of disturbed fluidization T2 - The 14th International Conference on Fluidization – From Fundamentals to Products N2 - Numerical simulations using the Two Fluid Model are performed for gas-solid bubbling fluidized beds. The possibility to detect disturbances in the fluidization process is investigated by common analysis of pressure fluctuations and variation of the computational domain. Additionally the influences of different particle sizes and superficial gas velocities are studied. The results are compared with bubble properties obtained from a digital image analysis technique KW - Fluidisierung Y1 - 2013 UR - http://dc.engconfintl.org/fluidization_xiv/71 PB - Engineering Conferences International CY - New York ER - TY - GEN A1 - Krautz, Hans Joachim A1 - Nimtz, Michael T1 - Flexible Operation of CCS Power Plants to Match Variable Renewable Energies T2 - Energy Procedia N2 - 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. KW - CCS; Flexibility; Post combustion capture; Oxyfuel; Solvent storage; Pipeline Y1 - 2013 U6 - https://doi.org/10.1016/j.egypro.2013.08.034 SN - 1876-6102 VL - 2013 IS - 40 SP - 294 EP - 303 ER - TY - GEN A1 - Krautz, Hans Joachim A1 - Corrêa da Silva, Rodrigo A1 - Kangwanpongpan, Tanin T1 - Flame pattern, temperatures and stability limits of pulverized oxy-coal combustion T2 - Fuel : the science and technology of fuel and energy N2 - 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. KW - Oxy-fuel; Pulverized coal combustion; Flame pattern; Stability limits Y1 - 2014 U6 - https://doi.org/10.1016/j.fuel.2013.07.049 SN - 0016-2361 IS - Vol. 115 SP - 507 EP - 520 ER - TY - GEN A1 - Abang, Roger Atini A1 - Lisk, Alexander A1 - Krautz, Hans Joachim T1 - Fireside corrosion of superheater materials under oxy-coal firing conditions T2 - Energy Procedia N2 - 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. Y1 - 2013 U6 - https://doi.org/10.1016/j.egypro.2013.08.035 SN - 1876-6102 VL - 40 SP - 304 EP - 311 ER - TY - GEN A1 - Lechner, Stefan A1 - Merzsch, Matthias A1 - Krautz, Hans Joachim T1 - Heat-transfer from horizontal tube bundles into fluidized beds with Geldart A lignite particles T2 - Powder Technology N2 - 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. KW - Fluidized bed KW - Lignite KW - Drying KW - Heat transfer KW - Horizontal tubes KW - Tube bundle Y1 - 2014 U6 - https://doi.org/10.1016/j.powtec.2013.10.041 IS - 253 SP - 14 EP - 21 ER - TY - CHAP A1 - Fischer, Ulrich A1 - Rabann, Bernd A1 - Krautz, Hans Joachim T1 - Wasserstoff – Elektrolyse T2 - Erneuerbare Energien : VBI-Leitfaden Y1 - 2015 SP - 85 EP - 92 PB - Verband Beratender Ingenieure CY - Berlin ET - 1. Auflage ER -