@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} } @misc{AbangWeissKrautz, author = {Abang, Roger Atini and Weiß, Sabine and Krautz, Hans Joachim}, title = {Impact of increased power plant cycling on the oxidation and corrosion of coal-fired superheater materials}, series = {Fuel}, volume = {2018}, journal = {Fuel}, number = {220}, issn = {0016-2361}, doi = {10.1016/j.fuel.2018.02.047}, pages = {521 -- 534}, abstract = {As power generation from variable renewable energy sources such as wind and solar power continues to increase in the future, fewer baseload power plants will be needed. As a result, high operational flexibility is becoming a vital requirement for conventional power plants to allow for the smooth integration of the variable renewable energy sources (v-RES) into the grid. To understand the impact of high operational flexibility (increased cycling) for coal-fired power plant materials, five commercial coal boiler superheater and reheater materials were investigated under isothermal and cyclic conditions for 1000 h each. The candidate alloys investigated were: T91, VM12-SHC, TP347-HFG, DMV304 HCu and DMV310 N. The results (weight change kinetics and metallographic analysis) after exposure at a metal surface temperature of 650 °C clearly showed the impact of increased flexibility on the corrosion and oxidation of the materials. Oxide growth (weight gain), metal loss, oxide spallation, and grain boundary attack were found to be more severe under cyclic conditions than under isothermal conditions.}, language = {en} } @misc{AhaFindeisenKrautz, author = {Aha, Ulrich and Findeisen, Alexander and Krautz, Hans Joachim}, title = {Maintenance optimization for large coal-fired power plants}, language = {en} } @misc{AhaFindeisenKrautzetal., author = {Aha, Ulrich and Findeisen, Alexander and Krautz, Hans Joachim and Kahlert, Joachim}, title = {Korrosion und Instandhaltungsoptimierung CO2-armer Braunkohlekraftwerke unter ge{\"a}nderten Prozessbedingungen und -parametern}, language = {de} } @misc{AsegehegnSchreiberKrautz, author = {Asegehegn, Teklay Weldeabzgi and Schreiber, Matthias and Krautz, Hans Joachim}, title = {Numerical Study of Bubbling Gas-Solid Fluidized Beds Hydrodynamics: Influence of Immersed Horizontal Tubes and Data Analysis}, language = {en} } @misc{AsegehegnSchreiberKrautz, author = {Asegehegn, Teklay Weldeabzgi and Schreiber, Matthias and Krautz, Hans Joachim}, title = {Investigation of bubble behavior in fluidized beds with and without immersed horizontal tubes using a digital image analysis technique}, doi = {http://dx.doi.org/10.1016/j.powtec.2011.03.025}, language = {en} } @misc{AsegehegnSchreiberKrautz, author = {Asegehegn, Teklay Weldeabzgi and Schreiber, Matthias and Krautz, Hans Joachim}, title = {Numerical simulation and experimental validation of bubble behavior in 2D gas-solid fluidized beds with immersed horizontal tubes}, doi = {http://dx.doi.org/10.1016/j.ces.2011.07.056}, language = {en} } @misc{AsegehegnSchreiberKrautz, author = {Asegehegn, Teklay Weldeabzgi and Schreiber, Matthias and Krautz, Hans Joachim}, title = {Influence of two- and three-dimensional simulations on bubble behaviorin gas-solid fluidized beds with and without immersed horizontal tubes}, doi = {10.1016/j.powtec.2011.11.050}, language = {en} } @misc{DahashMieckOchsetal., author = {Dahash, Abdulrahman and Mieck, Sebastian and Ochs, Fabian and Krautz, Hans Joachim}, title = {A comparative study of two simulation tools for the technical feasibility in terms of modeling district heating systems: An optimization case study}, series = {Simulation Modelling Practice and Theory}, volume = {91}, journal = {Simulation Modelling Practice and Theory}, issn = {1569-190X}, doi = {10.1016/j.simpat.2018.11.008}, pages = {48 -- 68}, abstract = {District heating dynamic models arise as an alternative approach to in-situ experimental investigations. The main advantage of dynamic modeling and simulation is the possibility to avoid technical and operational risks that might occur during in-situ experimental investigations (e.g. heat demand is not met, damages in the energy systems etc.). Within this study, the authors present two models for an existing district heating system in Cottbus, Germany. One model is developed using the tool EBSILON Professional, while the other one is developed using the Simscape toolbox for physical modeling in Matlab/Simulink. The models were experimentally validated against measured data from the considered district heating system. The results show that the Simscape model has a better fit and better response than the EBSILON model. Yet, some discrepancies were found between the measured and the simulated data and, therefore, the uncertainties of the models were addressed. A comparative study between both tools is presented. The EBSILON models permit only unidirectional flow, whereas the Simscape toolbox permits reverse flow. Nevertheless, the EBSILON model outperforms the Simscape model in computation time. In addition, this study presents an approach for dynamic thermo-hydraulic modeling of district heating networks. This approach is utilized to examine the role of district heating networks as heat storage as an optimization configuration. The numerical results show less start-ups for additional heat sources. Yet, higher heat losses from the network are observed due to the installation of unburied pipelines.}, language = {en} } @misc{FindeisenKlattKrautz, author = {Findeisen, Alexander and Klatt, Matthias and Krautz, Hans Joachim}, title = {Examination of the corrosion behaviour of selected power plant materials under various operating conditions}, doi = {http://dx.doi.org/10.1016/j.chemer.2010.05.006}, language = {en} }