International Scientific Journal


Binary fuels of a fluidized bed combustor or gasifier are solids composed of two groups of particles. Their optimal handling in the same bed becomes rather difficult if their hydrodynamic properties differ by two orders of magnitude or more. Both of these fuel classes are directly fed into the reactor in most cases but the rather homogeneous fuel originally fed switches into a binary character inside the reactor in some others. A typical example of the latter case is the thermal utilization of rubber wastes. A novel design is proposed in the present paper by setting up a non-mixing, non-elutriated binary bed. Design criteria and procedure are formulated as well. One of the known calculation methods is proposed to be applied for assuring a segregated bed by means of choosing the bed components, geometry, and gas velocity conveniently. Cold model experiments are proposed to be applied for assuring no elutriation of the fine fuel particles and no sinking of the coarse fuel particles in the same time. A simple experiment is proposed for determining the common minimum fluidization velocity of the binary bed because known calculation methods can not be applied here.
PAPER REVISED: 2016-02-08
PAPER ACCEPTED: 2016-03-07
CITATION EXPORT: view in browser or download as text file
THERMAL SCIENCE YEAR 2017, VOLUME 21, ISSUE Issue 2, PAGES [1105 - 1118]
  1. Szentannai P, Friebert A, Winter F. Renewable Fuels for Fluidized Bed Combustors: Current Status and Future Trends. Archivum Combustions 2008;28:77-84.
  2. Ninduangdee P, Kuprianov VI. Combustion of palm kernel shell in a fluidized bed: Optimization of biomass particle size and operating conditions. Energy Convers Manag 2014;85:800-8. doi:10.1016/j.enconman.2014.01.054.
  3. Sarker S, Bimbela F, Sánchez JL, Nielsen HK. Characterization and pilot scale fluidized bed gasification of herbaceous biomass: A case study on alfalfa pellets. Energy Convers Manag 2015;91:451-8. doi:10.1016/j.enconman.2014.12.034.
  4. Rao KVNS, Reddy GV. Cold Flow Studies of Rice Husk, Saw Dust, and Groundnut Shell Fuels in a Fluidized Bed. Energy Sources Part Recovery Util Environ Eff 2010;32:1701-11. doi:10.1080/15567030902882893.
  5. Scala F, Chirone R, Salatino P. Fluidized bed combustion of tyre derived fuel. Exp Therm Fluid Sci 2003;27:465-71. doi:10.1016/S0894-1777(02)00249-2.
  6. Rowe PN, Nienow AW, Agbim AJ. The mechanism by which particles segregate in gas fluidised beds: binary systems of near-spherical particles. Trans Inst Chem Eng 1972;50:310-24.
  7. Di Renzo A, Di Maio FP, Girimonte R, Vivacqua V. Segregation direction reversal of gas-fluidized biomass/inert mixtures - Experiments based on Particle Segregation Model predictions. Chem Eng J 2015;262:727-36. doi:10.1016/j.cej.2014.10.028.
  8. Gibilaro LG, Rowe PN. A model for a segregating gas fluidised bed. Chem Eng Sci 1974;29:1403-12. doi:10.1016/0009-2509(74)80164-8.
  9. Formisani B, Girimonte R, Vivacqua V. Fluidization of mixtures of two solids: A unified model of the transition to the fluidized state. AIChE J 2013;59:729-35. doi:10.1002/aic.13876.
  10. Palappan KG, Sai PST. Studies on segregation of binary mixture of solids in a continuous fast fluidized bed: Part I. Effect of particle density. Chem Eng J 2008;138:358-66. doi:10.1016/j.cej.2007.06.008.
  11. Nienow AW, Rowe PN, Cheung LY-L. A quantitative analysis of the mixing of two segregating powders of different density in a gas-fluidised bed. Powder Technol 1978;20:89-97. doi:10.1016/0032- 5910(78)80013-8.
  12. Goldschmidt MJV, Link JM, Mellema S, Kuipers JAM. Digital image analysis measurements of bed expansion and segregation dynamics in dense gas-fluidised beds. Powder Technol 2003;138:135-59. doi:10.1016/j.powtec.2003.09.003.
  13. Keller NKG, Bai W, Fox RO, Heindel TJ. Quantifying mixing in 3D binary particulate systems. Chem Eng Sci 2013;93:412-22. doi:10.1016/j.ces.2013.01.069.
  14. Bai W, Keller NKG, Heindel TJ, Fox RO. Numerical study of mixing and segregation in a biomass fluidized bed. Powder Technol 2013;237:355-66. doi:10.1016/j.powtec.2012.12.018.
  15. Palappan KG, Sai PST. Studies on segregation of binary mixture of solids in continuous fast fluidized bed: Part III. Quantification of performance of the segregator. Chem Eng J 2008;145:100-11. doi:10.1016/j.cej.2008.07.041.
  16. Cheung L, Nienow AW, Rowe PN. Minimum fluidisation velocity of a binary mixture of different sized particles. Chem Eng Sci 1974;29:1301-3. doi:10.1016/0009-2509(74)80137-5.
  17. Rowe PN, Nienow AW. Minimum fluidisation velocity of multi-component particle mixtures. Chem Eng Sci 1975;30:1365-9. doi:10.1016/0009-2509(75)85066-4.
  18. Hatch MR, Jacobs RB. Prediction of pressure drop in two-phase single-component fluid flow. AIChE J 1962;8:18-25. doi:10.1002/aic.690080108.
  19. Chiba S, Chiba T, Nienow AW, Kobayashi H. The minimum fluidisation velocity, bed expansion and pressure-drop profile of binary particle mixtures. Powder Technol 1979;22:255-69. doi:10.1016/0032- 5910(79)80031-5.
  20. Nawaz Z, Sun Y, Chu Y, Wei F. Mixing Behavior and Hydrodynamic Study of Gas-Solid-Solid Fluidization System: Co-Fluidization of FCC and Coarse Particles. 13th Int Conf Fluid - New Paradigm Fluid Eng 2010.
  21. Dobrovszky K. Upcycling of polymer waste from automotive industry. Period Polytech Mech Eng 2012;55:73-7. doi:10.3311/
  22. Szentannai P, Bozi J, Jakab E, Ősz J, Szűcs T. Towards the thermal utilisation of non-tyre rubbers - Macroscopic and chemical changes while approaching the process temperature. Fuel 2015;156:148-57. doi:10.1016/j.fuel.2015.04.037.
  23. Arena U, Chirone R, Salatino P. The fate of fixed carbon during the fluidized-bed combustion of a coal and two waste-derived fuels. Symp Int Combust 1996;26:3243-51. doi:10.1016/S0082- 0784(96)80170-6.
  24. Cammarota, A., Chirone, R., Salatino, P., Scala, F., Senneca, O. Fluidized Bed Combustion of Tyre Derived Fuel. Recycl. Reuse Used Tyres Proc. Int. Symp. Organised Concr. Technol. Unit Univ. Dundee, London: Thomas Telford; 2001.
  25. Palotás ÁB, Szemmelvesisz T, Winkler-Sátor L, Koós T, Koncz J, Bánhidi O, et al. Komplex Investigation of Alternative Fuels. Uni-Flexys Co.; 2013.
  26. Susekov ES, Gradov AS. Device for Production of Soot from Rubber Waste. US Patent. US 20140294686 A1, 2014.
  27. Palappan KG, Sai PST. Studies on segregation of binary mixture of solids in continuous fast fluidized bed: Part II. Effect of particle size. Chem Eng J 2008;139:330-8. doi:10.1016/j.cej.2007.08.003.
  28. Palappan KG, Sai PST. Studies on segregation of binary mixture of solids in a continuous fast-fluidized bed. Part IV. Total solids holdup, axial solids holdup and axial solids concentration. Chem Eng J 2010;158:257-65. doi:10.1016/j.cej.2010.01.027.
  29. Rowe PN, Nienow AW. Particle mixing and segregation in gas fluidised beds. A review. Powder Technol 1976;15:141-7. doi:10.1016/0032-5910(76)80042-3.
  30. Geldart D. Types of gas fluidization. Powder Technol 1973;7:285-92. doi:10.1016/0032- 5910(73)80037-3.
  31. Basu P. Combustion and gasification in fluidized beds. Boca Raton: CRC/Taylor & Francis; 2006.

© 2022 Society of Thermal Engineers of Serbia. Published by the Vinča Institute of Nuclear Sciences, National Institute of the Republic of Serbia, Belgrade, Serbia. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International licence