Residence time distribution of solids in multistage fluidisation

https://doi.org/10.1016/0009-2509(82)85009-4Get rights and content

Abstract

The residence time distribution of the solids in multistage fluidisation, wherein downcomers for transferring the solids from stage to stage are provided to the horizontal perforated plates, is experimentally investigated covering a wide range in process variables using flat, baffle and spiral plates developed in the study. The RTD data is modelled using (i) the multiple parameter model, (ii) the diffusional mixing model and (iii) the fractional tank extension model when it is noted that over certain conditions of operation both spiral and baffle plates indicate near piston-flow for the solids without hampering the fluidisation characteristics.

References (23)

  • Y.B.G. Varma

    Powder Technol.

    (1975)
  • J. Raghuraman et al.

    Chem. Engng Sci.

    (1973)
  • J. Raghuraman et al.

    Chem. Engng Sci.

    (1975)
  • P.V. Danckwerts

    Chem. Engng Sci.

    (1953)
  • J. Raghuraman et al.

    Chem. Engng Sci.

    (1973)
  • S.R. Tailby et al.

    Trans. Inst. Chem. Engrs

    (1961)
  • D.R. Morris et al.

    Trans. Inst. Chem. Engrs

    (1964)
  • K.M. Bowling et al.

    Aust. J. Appl. Sci.

    (1963)
  • G. Winterstein et al.

    Chem. Technol. (Berlin)

    (1961)
  • B.A. Buffham et al.

    A.I.Ch.E.J.

    (1968)
  • H.H. Rosenbrock et al.
    (1966)
  • Cited by (23)

    • Prediction of distribution behavior of particles with wide size distribution in baffled fluidized beds

      2019, Powder Technology
      Citation Excerpt :

      Therefore, the back-mixing coefficient (ϕ) accurately represents the effect of particle back-mixing on the movement of particles of different sizes. Generally, the MRT of WSD particles could be accurately predicted in previous studies (with the RTD models and MRT correlations) by using the average size to represent the WSD particles [5,25–27]. However, models that can predict the MRT of WSD particles of each size have not been presented to the best of our knowledge.

    • Modulating the mean residence time difference of wide-size particles in a fluidized bed

      2018, Chinese Journal of Chemical Engineering
      Citation Excerpt :

      Therefore, the MRT of the particle Fine in mixture II is smaller than that in mixture IV. Generally, the size ratio for the fine particles and the coarse particles in the mixtures with WSD can be more than 4 during the roasting of ilmenite powders [9,19] and direct reduction of iron ore. The synchronous conversion of such mixtures with WSD would require a theoretical MRT ratio of 4 and 16 under the chemical reaction and the film diffusion controlling mechanism, respectively.

    • CFD simulation of solids residence time distribution in a multi-compartment fluidized bed

      2017, Chinese Journal of Chemical Engineering
      Citation Excerpt :

      And this can be approached through dividing the bed into multi-compartment by using different types of baffles. Raghuraman and Varma [8,9] used an internal like a baffle or a spiral plate to increase the plug flow tendency of particles. Pydi Setty et al. [10,11] found that the increase in the number of stages could reduce the axial mixing and each stage behaved as a single stage unit, with the additional advantage of restricting the bubble growth.

    • Hydrodynamic and solids residence time distribution in a binary bubbling fluidized bed: 3D computational study coupled with the structure-based drag model

      2017, Chemical Engineering Journal
      Citation Excerpt :

      And the RTD of monodisperse BFB system is firstly computed and investigated to testify the correctness of our structure drag model more deeply. To validate the simulated method based on the structure-based drag model, the experimental data from Prasad Babu et al. [17] is selected among the limited publications [15–17] related to the hydrodynamic and solids RTD of binary components. Experiments were conducted in an 80 mm i.d. perspex column with the continuous solids being admitted into the bed bottom from the hopper and exiting through the downcomer with different heights.

    • Chemical-looping combustion-reactor fluidization studies and scale-up criteria

      2005, Capture Project: Vol 1 - Capture and Separation of Carbon Dioxide from Combustion, Vol 2 - Geologic Storage of Carbon Dioxide with Monitoring and Verification
    View all citing articles on Scopus
    View full text