Bioprocess Engineering

, Volume 14, Issue 2, pp 81–89

Pilot-scale verification of a computer-based simulation for the centrifugal recovery of biological particles

  • A. I. Clarkson
  • M. Bulmer
  • N. J. Titchener-Hooker
Originals

DOI: 10.1007/BF00387961

Cite this article as:
Clarkson, A.I., Bulmer, M. & Titchener-Hooker, N.J. Bioprocess Engineering (1996) 14: 81. doi:10.1007/BF00387961

Abstract

The development of a model for simulating the recoveries by pilot-scale disc-stack centrifugation of whole yeast cells, yeast cell debris and protein precipitates prepared by ammonium sulphate salting-out is presented. The model is based on the grade efficiency concept and incorporates the effects of hindered settling at high biomass concentrations and the breakage of shear-sensitive material within the centrifuge feed-zone to give an accurate prediction of solid/liquid separation. The simulations have been proven by comparison with data from pilot-scale verification trials. The trials have highlighted where improvements to the models were required to increase their accuracy. The value of verification trials in proving the validity of models is commented upon.

List of Symbols

Cv

volume concentration of solids in suspension (−)

D

dilution factor (−)

d

particle diameter (μm)

dc

critical particle diameter (μm)

E

enzyme activity (U mL−1)

ET

centrifuge mass yield (−)

g

acceleration due to gravity (9.81 ms−2)

k

constant (−)

kB

breakage constant (−)

n

constant (−)

Q

volumetric flowrate (m3 s−1)

R

total protein concentration (mg mL−1)

Ro

outer disc radius (m)

Ri

inner disc radius (m)

(T(d)

grade efficiency (−)

V

volume (L)

Z

number of discs (−)

Greek Symbols

Δϱ

solid-liquid density difference (Kg m−3)

Δt

change in time (s)

ΔF

representation for particle size distributions (−)

θ

disc conical half-angle (rads)

μ

suspension dynamic viscosity (N s m−2)

ρL

liquid phase density (Kg m−3)

ρA

aggregate phase density (Kg m−3)

Σ

area of a simple gravity settling tank of equivalent sedimentation characteristics to that of the centrifuge (m2)

σ

particle geometric factor (−)

ω

centrifuge angular velocity (rad s−1)

Subscripts

R

Total protein

E

Enzyme

PPT

Precipitant

s

Sheared

f

Feed

sup

Supernatant

sed

Sediment

Superscripts

ppt

Precipitate phase

sol

Soluble phase

Copyright information

© Springer-Verlag 1996

Authors and Affiliations

  • A. I. Clarkson
    • 1
  • M. Bulmer
    • 1
  • N. J. Titchener-Hooker
    • 1
  1. 1.The Advanced Centre For Biochemical Engineering, Department of Chemical and Biochemical EngineeringUniversity College LondonLondon
  2. 2.Costain Life Sciences Ltd.Manchester