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Mixing time in a down-flow jet loop bioreactor

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Abstract

Mixing time was determined in a down-flow jet loop bioreactor with Newtonian and non-Newtonian fluids. It was observed that the mixing time decreased with an increase in linear liquid velocity, superficial gas velocity, draft tube to column diameter ratio, nozzle diameter and shear thinning of media. The optimum draft tube to column diameter ratio was found to be about 0.44. Correlations were presented for prediction of mixing time.

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Abbreviations

A m2 :

cross sectional area of the column

C kmol/m3 :

local tracer concentration

A D m2 :

flow area,A D =π/4 (D Z 2 -D TO 2 )

D m:

column diameter

D E m:

draft tube diameter

D TO m:

outside diameter of the air tube

D TFL m:

equivalent flow diameter,D TFL =(D Z 2 -D TO 2 )0.5

D z m:

nozzle diameter

g m/s2 :

gravitational acceleration

h %:

inhomogeneity

H m:

height of the column

H B m:

distance between the lower edge of the draft tube and the impact plate

H T m:

distance between the upper edge of the draft tube and the liquid nozzle

K Pa.sn :

consistency index in power-law model

L E m:

length of the draft tube

n :

flow index in the power-law model

Re j :

jet Reynolds number,Re j =(D TFL×w1×ρL)/μ eff

t M s:

mixing time

t sg m/s:

superficial gas velocity based onA

W l m/s:

linear liquid velocity based onD D

τ N/m2 :

shear stress

γ s:

shear rate

ρ kg/m3 :

density of liquid

σ N/m:

surface tension of the liquid

μ Pa.sn :

viscosity of liquid

∞X:

concentration at infinite time maximum value of tracer concentration

eff:

effective

L:

Liquid

obs:

observed

pred:

Predicted

References

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Author information

Correspondence to T. K. Ramanujam.

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Velan, M., Ramanujam, T.K. Mixing time in a down-flow jet loop bioreactor. Bioprocess Engineering 12, 81–86 (1995). https://doi.org/10.1007/BF01112997

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Keywords

  • Waste Water
  • Water Management
  • Water Pollution
  • Diameter Ratio
  • Liquid Velocity