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Rotary Kilns

For modeling processes in rotary kilns, reduced mathematical models are developed for heat transfer, flame spread and for the movement of material . On the basis all processes are simulated.

It describes the influence of the length, the diameter, the rotational speed and the degree of filling of the rotary kiln as well as the properties of the material, among others. For the transverse transport mathematical models are derived, which described the slip line, the speed profiles and the local mass flows. The theoretical results are in relatively good agreement with our own and other readings. For further measurements, there is a joint research project with Prof. Dr. P. Walzel of the University of Dortmund. The flame spread is calculated with the CFD program system FLUENT.

Under investigation is the influence of the air preheating, the fuel type of material (coal, oil, gas), the twist and the burner construction. On the basis of known theories relationships between the variables and the type of fuel are derived. To describe the complicated mechanism of heat transport, models for transport over the wall and in the moving bed are worked out depending on the material properties of the wall or the bulk material.

The experimental determination of heat transfer a test furnace will be used  (internal diameter 400 mm). The furnace can be continuously measured up to 1100 ° C in the radial and axial temperature field. In addition, the axial course of the gas concentrations can be detected. The furnace can be operated in parallel and counter flow. The speed and inclination can be adjusted.

Temperaturprofil Frehrohrofen

 

more informations, see pilot plant rotary kilns and in information brochure

 

Selected publications of the research area

  • Herz, F.; Specht, E.: Simulation thermischer Prozesse in Drehrohröfen - Teil 2 Modellvalidierung. gwi - Gaswärme International, 65, 4 (2016), 41-46.
  • Herz, F.; Specht, E.: Simulation thermischer Prozesse in Drehrohröfen – Teil 1 Modellentwicklung. gwi – Gaswärme International, 3 (2016), 37-45.
  • Liu, X.; Xu, X.; Wu, W.; Herz, F.; Specht, E.: A simplified model to calculate the power draw for material movement in industrial rotary kilns. Powder Technology, 301 (2016), 1294-1298.
  • Nafsun, A.I.; Herz, F.: The effect of solid bed dispersity on the contact heat transfer in rotary drums. Proceedings of the 12th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics (HEFAT 2016), July 11-13, 2016, Malaga, Spain.
  • Nafsun, A.I.; Herz, F.; Specht, E.; Komossa, H.; Wirtz, S.; Scherer, V.: Heat transport through the active layer of the moving bed in rotary drums. Proceedings of the 12th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics (HEFAT 2016), July 11-13, 2016, Malaga, Spain.
  • Nafsun, A.I.; Herz, F.: Experiments on the temperature distribution in the solid bed of rotary drums. Applied Thermal Engineering, 103 (2016), 1039-1047.
  • Nafsun, A.I.; Herz, F.; Specht, E.; Scherer, V.; Wirtz, S.: Heat transfer experiments in a rotary drum for a variety of granular materials. Experimental Heat Transfer, 29 (2016), 520-535.
  • Karali, M.A.; Herz, F.; Specht, E.; Mellmann, J.: Comparison of image analysis methods to determine the ‎optimum loading of flighted rotary drums. Powder Technology, 291 (2016), 147-153.
  • Karali, M.A.; Sunkara, K.R.; Herz, F.; Specht, E.: Experimental analysis of a flighted rotary drum to assess the ‎optimum loading. Chemical Engineering Science, 138 (2015), 772-779.
  • Komossa, H.; Wirtz, S.; Scherer, V.; Herz, F.; Specht, E.: Heat transfer in indirect heated rotary drums filled with monodisperse spheres: Comparison of experiments with DEM simulations. Powder Technology, 286 (2015), 722-731.
  • Herz, F.; Karali, M.A.; Specht, E.: Experimental determination of the discharge ‎characteristics of a flighted rotary drum operated ‎at the optimum loading. Proceedings of the Joint Conference of the 5th UK-China and 13th UK Particle Technology Forum, July 12-15, 2015, Leeds, United Kingdom.
  • Herz, F.; Nafsun, A.I.; Liu, X.: Heat transfer analysis in a rotary drum. Proceedings of the Joint Conference of the 5th UK-China and 13th UK Particle Technology Forum, July 12-15, 2015, Leeds, United Kingdom.
  • Komossa, H.; Wirtz, S.; Scherer, V.; Nafsun, A.I.; Herz, F.; Specht, E.: DEM investigation of transversal mixing and temperature evolution in rotary drums. Proceedings of the 11th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics (HEFAT 2015), July 20-23, 2015, Kruger National Park, South Africa.
  • Nafsun, A.I.; Herz, F.; Specht, E.; Komossa, H.; Wirtz, S.; Scherer, V.: Experimental investigation of thermal bed mixing in rotary drums. Proceedings of the 11th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics (HEFAT 2015), July 20-23, 2015, Kruger National Park, South Africa.
  • Komossa, H; Wirtz, S.; Scherer, V.; Herz, F.; Specht, E.: Analysis of the particle velocity in the solid bed of rotary drums. Proceedings of the 8th International Conference for Conveying and Handling of Particulate Solids (CHoPS 2015). May 03-07, 2015, Tel-Aviv, Israel.
  • Herz, F.; Sunkara, K.R.; Specht, E.; Mellmann, J.: Discharge characteristics in flighted rotary drums. Proceedings of the 8th International Conference for Conveying and Handling of Particulate Solids (CHoPS 2015). May 03-07, 2015, Tel-Aviv, Israel.
  • Sunkara, K.R.; Herz, F.; Specht, E.; Mellmann, J.: Transverse flow at the flight surface in flighted rotary drums. Powder Technology, 275 (2015), 161-171.
  • Herz, F.; Mitov, I.; Specht, E.; Stanev, R.: Influence of the motion behavior on the contact heat transfer between the covered wall and solid bed in rotary kilns. Experimental Heat Transfer, 28 (2015), 174-188.
  • Komossa, H.; Höhner, D.; Wirtz, S.; Scherer, V.; Specht, E.; Herz, F.: Berechnung der Systemantworten von Drehrohren mit der Diskreten Elemente Methode als Basis für Modellansätze der instationären Prozesssimulation im Kontext der Biomasseaufbereitung. DGMK-Fachbereichstagung: Konversion von Biomassen, Mai 12-14, 2014, Rotenburg, Germany.
  • Nafsun, A.I.; Herz, F.; Specht, E.; Scherer, V.; Wirtz, S.: The contact heat transfer in rotary kilns and the effect of material properties. Proceedings of the 10th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics (HEFAT 2014), July 14-16, 2014, Orlando, USA.
  • Nafsun, A.I.; Herz, F.; Specht, E.: Analysis of heat penetration into the solid bed of rotary drums. Proceedings of the 10th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics (HEFAT 2014), July 14-16, 2014, Orlando, USA.
  • Nafsun, A.I.; Herz, F.; Specht, E.; Scherer, V.; Wirtz, S.; Komossa, H.: The contact heat transfer in rotary drums in dependence on the particle size ratio. Proceedings of the 15th International Heat Transfer Conference (IHTC-15), August 10-15, 2014, Kyoto, Japan.
  • Komossa, H.; Wirtz, S.; Scherer, V.; Specht, E.; Herz, F.: Transversal bed motion in rotating drums using spherical particles: Comparison of experiments with DEM simulations. Powder Technology, 264 (2014), 96-104
  • Stanev, R.; Mitov, I.; Specht, E.; Herz, F.: Geometrical characteristics of the solid bed in a rotary kiln. Journal of Chemical Technology and Metallurgy, 49, 1 (2014), 82-89.
  • Sunkara, R.K.; Herz, F.; Specht, E.; Mellmann, J.: Erpelding, R.: Modeling the discharge characteristics of rectangular flights in a flighted rotary drum. Powder Technology 234 (2013), 107-116.
  • Sunkara, R.K.; Herz, F.; Specht, E.; Mellmann, J.: Influence of flight design on the particle distribution of a flighted rotating drum. Chemical Engineering Science 90 (2013), 101-109.
  • Herz, F.; Specht, E.; Stanev, R.: The simulation of the quartz sand calcination in rotary kilns. Proceedings of the 15th Balkan Mineral Processing Congress (BMPC 2013), June 12-16, 2013, Sozopol, Bulgaria, ISBN 978-954-353-217-9.
  • Herz, F.; Nafsun, A.; Specht, E.; Scherer, V.; Stanev, R.: Experimental analysis of the contact heat transfer in rotary kilns. Proceedings of the 8th World Conference on Experimental Heat Transfer, Fluid Dynamics and Thermodynamics, June 16-20, 2013, Lisbon, Portugal, ISBN 978-972-8620-23-3.
  • Sunkara, K.R.; Herz, F.; Specht, E.; Mellmann, J.: Theoretical and experimental analysis of the optimal surface area of the cascading particles in a flighted rotating drum. Proceedings of the 5th Asian Particle Technology Symposium (APT 2012), July 2-5, 2012, Singapore.
  • Herz, F.; Mitov, I.; Specht, E.; Stanev, R.: Influence of operational parameters and material properties on the contact heat transfer in rotary kilns. The International Journal of Heat and Mass Transfer 55 (2012), 7941-794.
  • Herz, F.; Mitov, I.; Specht, E.; Stanev, R.: Experimental study of the contact heat transfer coefficient between the covered wall and solid bed in rotary drums. Chemical Engineering Science 82 (2012), 312-318.
  • Sunkara, K.R.; Herz, F.; Specht, E.; Mellmann, J.: Influence of flight cascading rate on the particle distribution in a flighted rotary drum. Proceedings of the 24th International Mineral Processing Congress (IMPC 2012), September 24-28, 2012, New Delhi, India, Paper 949, ISBN 81-901714-3-7.
  • Sunkara, K.R.; Herz, F.; Specht, E.; Mellmann, J.: A study on the influencing parameters of the particle motion in a flighted rotary drum. Proceedings of the 7th International Conference for Conveying and Handling of Particulate Solids (CHoPS 2012), September 10-13, 2012, Friedrichshafen, Germany.
  • Shi, Y.; Specht, E.; Herz, F.; Knabbe, J.; Sprinz, U.: Experimental investigation of the axial discharging velocity of particles from rotary kilns. Granular Matter 13 (2011), 465-473.
  • Sunkara, R.K..; Herz, F.; Specht, E.: Thermal fluctuations and heat transfer measurements in an externally heated rotary cylinder. Proceedings of the ASME/JSME 8th Thermal Engineering Joint Conference (AJTEC2011-44573), March 13-17, 2011, Honolulu, Hawaii, USA.
  • Herz, F.; Sonavane, Y.; Specht, E.: Analysis of local heat transfer in direct fired rotary kilns. Proceedings of the 14th International Heat Transfer Conference (IHTC14-22086), August 8-13, 2010, Washington, DC, USA.
  • Liu, X.Y.; Zhou, S.J.; Specht, E.: Avalanche Time of Granular Flows in Rotary Kilns. Chemical Engineering &Technology 33 (2010), 1029-1033.
  • Liu, X.Y.; Specht, E.: Predicting the fraction of the mixing zone of a rolling bed in rotary kilns. Chemical Engineering Science 65 (2010), 3059-3063.
  • Liu, X.Y; Specht, E.: Temperature distribution within the moving bed of rotary kilns: Measurement and analysis. Chemical Engineering&Processing 49 (2010), 147-150.
  • Shi, Y.; Woche, H.; Specht, E.; Knabbe, J.; Sprinz, U.: Experimental investigation of solid bed depth at the discharge end of rotary kilns. Powder Technology 197 (2010), 17-24.
  • Sonavane, Y.; Specht, E.: Numerical analysis of the heat transfer in the wall of rotary kiln using finite element method ANSYS. Proceedings of 7th International Conference on CFD in the Minerals and Process Industries (CSIRO), 09-11 December 2009, Melbourne, Australia.
  • Sonavane, Y.; Specht, E.: Numerical modelling of the rotary kilns in the industrial processes by using ANSYS (Finite Element Method). Proceedings of 5th International Conference on Diffusion in Solids and Liquids, 24-26 June 2009, Rome, Italy.
  • Sonavane, Y.; Specht, E.: Study of temperature profile in the agitated bed of pilot scale externally heated rotary kiln. Proceedings of AICHE Spring National Meeting, 26.-30. April 2009 Tampa (Florida), USA. ISBN 978-0-8169-1052-6.
  • Liu, X.Y.; Zhou, S.J.; Specht, E.: Image-based measurement of the surface profile of the cascading granular materials in rotating cylinders. Proceedings of 8th International Conference on Measurement and Control of Granular Materials (MCGM), Shenyang, China, 27-29 August 2009, 37-39. ISBN 978-7-81102-737-2.
  • Liu, X.Y.; Herz, F.; Specht, E.; Bensmann, S.; Gonzales, O.G.; Walzel, P.: Modeling the Transversal Motion of Granular Materials in Rotary Drums. Proceedings of 8th International Conference on Measurement and Control of Granular Materials (MCGM), Shenyang, China, 27-29 August 2009, 87-90. ISBN 978-7-81102-737-2.
  • Herz, F.; Sonavane, Y.; Specht, E.; Bensmann, S.; Walzel, P.: Mixing behaviour for the mass and heat transport of granular material in the agitated bed of rotating drums. Proceedings of 8th International Conference on Measurement and Control of Granular Materials (MCGM), Shenyang, China, 27-29 Aug. 2009, 21-27.
  • Herz, F.; Sonavane, Y.; Specht, E.; Bensmann S.; Walzel, P.: Mixing behaviour of granular material in the agitated bed of rotating drums. Bulk Solids and Powder-Science and Technology 4 (2009), 109-116.
  • Liu, X.; Zhang, J.; Specht, E.; Shi, Y.; Herz, F.: Analytical solution for the axial solids transport in rotary kilns. Chemical Engineering Science 64 (2009) 2, 428-431.
  • Agustini, S.; Queck, A.; Specht, E.: Modeling of the regenerative heat flow of the wall in direct fired rotary kilns. Heat Transfer Engineering 29 (2008) 1, 57-66.
  • Liu, X.; Specht, E.: Mean residence time and hold-up of solids in rotary kilns. Chemical Engineering Science 61 (2006), 5176-5181.
  • Liu, X.; Specht, E.; Guerra Gonzales, O.; Walzel, P.: Analytical solution of the rolling - mode granular motion in rotary kilns. Chemical Engineering and Processing 45 (2006), 515-521.
  • Agustini, S.; Specht, E.: Influence of the Regenerative Heat of the Wall on the overall Heat Transfer in Rotary Kilns. Cement international 3 (2005), 60-73.
  • Liu, X.; Specht, E; Mellmann, J.: Experimental study of the upper and lower angle of repose of granular materials in rotating drums. Powder Technology 154 (2005), 125-131.
  • Liu; X.; Specht, E.; Mellmann, J.: Slumping-rolling transition of granular solids in rotary kilns. Chemical Engineering Science 60 (2005), 3629-3636.
  • Liu, X.; Mellmann, J; Specht, E.: Factors influencing the rolling bed motion and transversial residence time of particles in rotary kilns. Cement, Lime, Gypsum International 58 (2005), 62-73.
  • Mellmann, J.; Liu, X.; Specht, E.: Prediction of Rolling Bed Motion in Rotating Cylinders. AICHE Journal 50 (2004) 1, 2783-2793.
  • Giese, A.; Specht, E.: Einfluss der Gaszusammensetzung auf die Flammenlänge in Drehrohröfen. VDI Berichte Nr. 1750 (21. Deutsche Flammentag) (2003), 145-152.
  • Mellmann, J.; Specht, E.: Mathematical Modelling of the Transition Behaviour between the various Forms of Transverse Motion of Bulk Materials in Rotating Cylinders (Part 2). English and German. Cement, Lime, Gypsum International 54 (2001), 380-402.
  • Mellmann, J.; Specht, E.: Mathematische Modellierung des Übergangsverhaltens zwischen den Formen der transversalen Schüttgutbewegung in Drehrohren (Teil 1). Englisch und Deutsch. Zement, Kalk, Gips International 54 (2001), 281-296.

 

Promotions of the Research Area:

  • Dr.-Ing. Aainaa Izyan Nafsun: Experimental analysis of heat transport in the solid bed of rotary kilns (26.11.2015)
  • Dr.-Ing. Mohammed Karali: Analysis study of the axial transport and heat transfer of a flighted rotary drum operated at optimum loading (20.08.2015)
  • Dr.-Ing. Koteswara Rao Sunkara: Granular flow and design studies in flighted rotating drums (11.07.2013)
  • Dr.-Ing. Fabian Herz: Entwicklung eines mathematischen Modells zur Simulation thermischer Prozesse in Drehrohröfen (23.07.2012)
  • Dr.-Ing. Hassan Fawzy Mohamed Elattar: Flame simulation in rotary kilns using computational fluid dynamics (08.09.2011)
  • Dr.-Ing. Yogesh Sonavane: Influence of the wall on the heat transfer process in rotary kilns (15.06.2010)
  • Dr.-Ing. Yichun Shi: The outflow behaviour of particles at the discharge end of rotary kilns (03.07.2009)
  • Dr.-Ing. Silvia Agustini: Regenerative action of the wall on the heat transfer for directly and indirectly heated rotary kilns (10.07.2006)
  • Dr.-Ing. Xiaoyan Liu: Experimental and theoretical study of transverse solids motion in rotary kilns (19.05.2005)
  • Dr.-Ing. Anne Giese: Numerische Untersuchungen zur Bestimmung der Flammenlängen in Drehrohröfen (13.06.2003)
  • Dr.-Ing. Andreas Queck: Untersuchung des gas- und wandseitigen Wärmetransportes in die Schüttung von Drehrohröfen (07.10.2002)

 

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