Skip to main content
SpringerLink
Log in

Axial dispersion in a liquid fluidized bed of particles akin to immobilized enzymes

  • Session 4 Bioengineering Research
  • Published:
Applied Biochemistry and Biotechnology Aims and scope Submit manuscript

Abstract

The axial dispersion of a liquid fluidized bed of controlled pore silica (CPS) particles has been determined by the pulse tracer method. The CPS used was the same as for enzyme immobilization, having an average diameter of 0.436 mm and mean pore size of 37.5 nm. The fluidization liquid is α-amylase liquefied manioc starch, 30% w/v, 45°C pH=4.5. Nominal bed porosities tested were 0.7 and 0.8. The results show that the axial dispersion coefficient increases with greater superficial liquid velocities. Various available correlations tested disagree with each other to a large extent and are unable to represent collected experimental data.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Log in via an institution

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Institutional subscriptions

Similar content being viewed by others

Abbreviations

C t :

tracer concentration at the reactor outlet, mg/cm3

D :

axial dispersion coefficient, cm2/s

D t :

blue dextran molecular diffusion in the fluidizing solution 4.44×10−8 cm2/s (12)

D 0 :

axial dispersion coefficient for empty tubes,D 0=Dt+u2 d 2i / (192D t) (10), cm2/s

d i :

reactor internal diameter, mm

d p :

average particle diameter, mm

Et :

residence time distribution, 1/s

Eθ :

dimensionless Et:Egθ=t R Et

g :

gravitational acceleration, cm2/s

H 0 :

minimum fluidization bed height, mm

L :

expanded bed height, mm

M i :

tracer injected mass, mg

M s :

fluidized solid total mass, g

n :

Richardson and Zaki expansion index:u/u t=∈n

P e :

mass transfer Peclet number

Q :

defined by Eq. (8)

r :

correlation coefficient

R% :

percentage of recovered tracer relative to total mass injected

R e :

particle Reynolds numberR e=σu d p/μ

R emf :

Reynolds number at minimum fluidization

t :

sampling time, s

t R :

mean residence time of the fluid inside the ractor, s

t 1 :

first moment of the reactor outlet tracer concentration distribution, s

u :

fluidizing fluid superficial velocity, cm/s

u i :

fluidizing fluid intersticial velocity:u i=u/∈, cm/s

u t :

particle terminal velocity, cm/s

u mf :

minimum fluidization velocity, cm/s

v :

fluidizing fluid volumetric flow rate, cm3/s

V I :

actual liquid volume in the reactor:V I=∈ Vt cm3

V T :

total bed volumeV T=πd 2 i L/4, cm3

∈:

fluidized bed porosity ∈=1-Ms/σs V T

θ:

dimensionless time: θ=t/t R

μ:

fluidizing liquid viscosity, g/cm s

v :

kinematic viscosity,v=μ/σ, cm2/s

ρ:

fluidizing liquid density, g/cm3

ρσ :

particle density, g/cm3

ρs :

particle matrix density, g/cm3

ρap :

wet particle apparent density, g/cm3

σ2 :

variance of the reactor outlet tracer concentration distribution s2

σ 2θ :

dimensionless σ2: σ 2θ =σ2/t 21

τe :

space-time τe=L/u i=V l.v, s

References

  1. Burli, A. B., Senthilnathan, P. R., and Subramanian, N. (1979),Can. J. Chem. Eng. 57, 648–650.

    Google Scholar 

  2. Busche, R. M., and Allen, B. R. (1989),Appl. Biochem. Biotechnol. 20–21, 357–374.

    Google Scholar 

  3. Andrews, G. F., and Fonta, J. P. (1989),Appl. Biochem. Biotechnol. 20–21, 375–390.

    Google Scholar 

  4. Davidson, J. F., Clift, R., and Harrison, D. (1985),Fluidization, 2nd ed., Academic, London.

    Google Scholar 

  5. Wen, C. Y., and Fan, L. S. (1973),Chem. Eng. Sci. 28, 1768–1772.

    Article  CAS  Google Scholar 

  6. Bruinzel, C., Reman, G. H., and van der Laan, E. T. H. (1960),Proceedings of the Symposium on Interaction between Fluids and Particles, Institute of Chemical Engineering, London, 136.

  7. Chung, S. F., and Wen, C. Y. (1968),AIChe. J. 14, 857–866.

    Article  CAS  Google Scholar 

  8. Krishnaswamy, P. R., and Shemilt, L. W. (1972),Can. J. Chem. Eng. 50, 419–420.

    CAS  Google Scholar 

  9. Krishnaswamy, P. R., Ganapathy, R., and Shemilt, L. W. (1978),Can. J. Chem. Eng. 56, 550–553.

    CAS  Google Scholar 

  10. Levenspiel, O. (1972), inChemical Reaction Engineering, 2nd ed., John Wiley & Sons, New York, Chapter 9, pp. 253–325.

    Google Scholar 

  11. Zanin, G. M., Kambara, L. M., Calsavara, L. P. V., and de Moraes, F. F. (1988),Proceedings of XVI Encontro sobre Escoamento em Meios Porosos,I, 234–252.

    Google Scholar 

  12. Zanin, G. M. (1989), Sacarificacao de Amido em Reator de Leito Fluidizado com Enzima Amiloglicosidase Imobilizada. Ph.D. Thesis, Faculdade de Engenharia de alimentos, Universidade Estadual de Campinas, Campinas SP, Brasil.

    Google Scholar 

  13. Zanin, G. M. and de Moraes, F. F. (1984),Proceedings of XII Encontro sobre Escoamento em Meios Porosos Maringa,I, 267–285.

    Google Scholar 

  14. Metha, S. C., and Shemilt, L. W. (1976),Can. J. Chem. Eng. 54, 43–51.

    Article  Google Scholar 

  15. van der Meer, A. P., and Wesselingh, J. A. (1986), inHeat and Mass Transfer in Fixed and Fluidized Beds, van Swaaij, W. P. M. and Afgan, N. H., eds., Springer-Verlag, Berlin, pp. 601–613.

    Google Scholar 

  16. Levenspiel, O., and Bischoff, K. B. (1963),Adv. Chem. Eng. 4, 95–198.

    CAS  Google Scholar 

  17. Zanin, G. M. and de Moraes, F. F. (1989),Revista de Microbiologia 20(3), 367–371.

    CAS  Google Scholar 

  18. Zanin, G. M. and de Moraes, F. F. (1983),Revista Brasileira de Engenharia Quimica 7, 47–58.

    CAS  Google Scholar 

  19. Froment, G. F., and Bischoff, K. B. (1990), inChemical Reactor Analysis and Design, 2nd ed., John Wiley and Sons, New York, p. 530.

    Google Scholar 

  20. Brenner, H. (1962),Chem. Eng. Sci. 17, 229–243.

    Article  CAS  Google Scholar 

  21. Emery, A. N., and Cardoso, J. P. (1978),Biotechnol. Bioeng. 20, 1903–1929.

    Article  CAS  Google Scholar 

  22. Cabral, J. M. S. (1982), Estudos de Imobilizacao de Enzimas pelo Metodo dos Metais de Transicao, Ph.D. Thesis, Universidade Tecnica de Lisboa.

  23. Zanin, G. M. and de Moraes, F. F. (1983),Proceedings of XI Encontro sobre Escoamento em Meios Porosos, Rio de Janeiro,II, 64–82.

    Google Scholar 

Download references

Author information

Authors and Affiliations

  1. Chemical Engineering Department, Maringa State University, 87020-900, Maringa, PR, Brazil

    Gisella M. Zanin, Ivo Neitzel & Flavio F. De Moraes

Authors
  1. Gisella M. Zanin
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. Ivo Neitzel
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. Flavio F. De Moraes
    View author publications

    You can also search for this author in PubMed Google Scholar

Rights and permissions

Reprints and permissions

About this article

Cite this article

Zanin, G.M., Neitzel, I. & De Moraes, F.F. Axial dispersion in a liquid fluidized bed of particles akin to immobilized enzymes. Appl Biochem Biotechnol 39, 477–489 (1993). https://doi.org/10.1007/BF02919012

Download citation

  • Issue Date:

  • DOI: https://doi.org/10.1007/BF02919012

Index Entries

Search

Navigation