Introduction to Centrifugation For
The Biotechnology Industry
Speakers:
Aaron Allen – Jacobs Engineering Group
Larry James – CRB Consulting Engineers Inc.
Mark Trotter – Sartorius Stedim Biotech
Michael Rohr – Westfalia Separator Inc
3/6/2008
ISPE Carolina South-Atlantic
Chapter
1
1. Introduction to Sedimentation Centrifugation
Principles & Design
2. Overview of Process Parameters for Optimization
3. Typical Scope of Supply for Skid Systems
4. Typical Applications for Biotech Centrifuges
5. CIP Approach
3/6/2008
ISPE Carolina South-Atlantic
Chapter
2
1. Introduction to Sedimentation Centrifugation
Principles & Design
3/6/2008
ISPE Carolina South-Atlantic
Chapter
3
Typical Fermentation Process Flow Sheet
Including Centrifuge
Typical feed concentration 1-2 % (v/v)
depends on vaccine
Mammalian cells
3/6/2008
ISPE Carolina South-Atlantic
Chapter
4
Particle Size Distribution
Particles of different
sizes and densities
must be removed by the
centrifuge. The large
ones are easier than the
small rate limiting ones.
3/6/2008
ISPE Carolina South-Atlantic
Chapter
5
Calculation of the Settling Speed
ρf
πd p ρ f 2
Fw = c w ⋅ A ⋅
⋅ v = cw ⋅
⋅
⋅ vg
2
4
2
(Resisting force)
With
cw =
(Lifting force)
Follows:
Spherical
particle
(Weight)
FG=FA +
FW
3/6/2008
24
Re
for
2
g
d p ⋅ vg ⋅ ρ f
Re =
< 0,5
ηf
Fw = 3⋅π ⋅ηf ⋅dp ⋅ vg
π d 3p
FA =
⋅ ρl ⋅ g
6
π d 3p
FG =
⋅ ρs ⋅ g
6
∆ ρ ⋅ d 2p
vg =
⋅g
18 ⋅ η f
ISPE Carolina South-Atlantic
Chapter
Stoke’s Law of settling
6
Gravity Settling
Volume
Rate = Residence Time
H1
Settling distance
Velocity
< Tres
= Capture
H2
Short Settling Distance
Additional Settling Surface
Particles settle from the fluid via gravity
in the spaces between the plates
H1
Residence Time
Capture
Surface Area
Centrifugal Acceleration
Centrifugal Force
Residence Time
Surface Area
Capture
Particle Separation in the Centrifuge
dlimit
Vfl
Vr
Vf
ω
Vfl
Q
Vf
Vr
dlimit
Q
dlimit :
Vf :
Vfl :
Vr :
3/6/2008
ω
ϕ
min. particle size capured
”centrifugal” speed
”flow” speed
resulting speed
Q:
η:
∆ρ :
ω:
flow rate
dyn. viscosity
delta density
speed of rotation
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Chapter
d2limit ~ Qη / (∆ρω 2)
10
Ejecting Solids
Clarification Capacity
Liquid Clarity
Flow Rate
Solids Capacity
Sediment Space
Discharge Volume
Solids Flow Rate
Process Flowpath Through
Separation Area
Feed in
Centrate out
Low Shear
feed zone
Disc Stack
Sediment
Holding
Space
Peripheral
Solids
Discharge
3/6/2008
ISPE Carolina South-Atlantic
Chapter
12
Ejection of Solids Control
Benefits of variable shot control…
• Higher product yield (less losses)
• Shorter harvest time (no buffer flushes)
Largest small partial ejection
Medium small partial ejection
Smallest small partial ejection
3/6/2008
ISPE Carolina South-Atlantic
Chapter
13
Self-Cleaning Stacked-Disc Centrifuge
With Automatic Solids Ejection
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Chapter
14
Disc Comparison
Electro polished disc
Standard disc
Centripetal Pump Discharge - Pumping Liquid
Clarified rotating liquid
from the disc stack
enters the upper
discharge chamber
within the bowl and is
picked up by the
Stationary Centripetal
Pump head and
Discharges through the
channels under
Pressure.
1. Introduction to Sedimentation Centrifugation
Principles & Design
2. Overview of Process Parameters for Optimization
3/6/2008
ISPE Carolina South-Atlantic
Chapter
17
1. Feedrate to centrifuge > monitor centrate quality
> in line turbidity
> spin down analysis
> filter testing
2. Shear force via bowl rpms > cell culture only
> HydroHermetic Feed
> centrate backpressure
3. Solids ejection interval > usually maximize interval
> monitor centrate quality
4. Solids ejection volume > adjust to minimize losses
5. Scale up using Sigma
3/6/2008
> see next slide
ISPE Carolina South-Atlantic
Chapter
18
Process Parameter Considerations
For Mechanical Separation
Product-Related Parameters
•Density Difference
•Viscosity of Carrier Liquid
•Particle Size & Distribution
•Solids consistency
Stokes
•Surface Tension
Gravitational Velocity V g =
Particle Dia2 x ∆ Density X g
18u (viscosity)
Application Related Parameters
•% of Phases Present
•Desired Purity
•Flow Required
•Temperature
•Corrosion / Erosion
•Operational Restrictions, xp etc
•Clear Centrate or Dry Solids?
Separation Factors
•Settling Distance
•Residence Time
•Time at Laminar Flow
•Settling Surface Area
•G Force I/e Bowl Speed
Terminal Settling
Velocity V c=
Vg x RPM2 x R
Gravity
Throughput via Effective
Clarification Area
d=
∆q =
u=
g=
n=
z=
e=
r1=
r2=
Q=
Particle diameter (m)
Density difference (kg/m3)
Dynamic viscosity (kg/ms)
Gravity (9.8 m/s/s)
Speed (rpm)
Number of discs
Tan of disc angle
Outer disc radius (m)
Inner disc radius (m)
Q = Vs x ∑T
Throughput rate (ml/s)
Area Equivalent ∑T
Q =
d2 x ∆q x g
x
18 u
π xn
2π
2
x
3g
x
z
x
e
x
( r1 3 - r2
30
W2
Stokes Vs
Angular velocity
3
)
1. Introduction to Sedimentation Centrifugation
Principles & Design
2. Overview of Process Parameters for Optimization
3. Typical Scope of Supply for Skid Systems
3/6/2008
ISPE Carolina South-Atlantic
Chapter
21
Whisperfuge
Bench Top Centrifuge
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Chapter
22
Skid Mounted Centrifuge System
CSC6-06-476 SIP / CIP
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Chapter
23
CSC 20 Package Unit
for the recovery of human vaccines
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ISPE Carolina South-Atlantic
Chapter
24
CSE 80-06-476 Skid Package
CIP / SIP
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Chapter
25
CSE 130-06-476 Skid Package
CIP / SIP
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Chapter
26
CSE 170 SIP-Package unit
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ISPE Carolina South-Atlantic
Chapter
27
1. Introduction to Sedimentation Centrifugation
Principles & Design
2. Overview of Process Parameters for Optimization
3. Typical Scope of Supply for Skid Systems
4. Typical Applications for Biotech Centrifuges
3/6/2008
ISPE Carolina South-Atlantic
Chapter
28
ENZYMES flowsheet - Extracellular
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Chapter
29
VACCINES flowsheet
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Chapter
30
CSE 170 SIP-Package unit
3/6/2008
ISPE Carolina South-Atlantic
Chapter
31
1. Introduction to Sedimentation Centrifugation
Principles & Design
2. Overview of Process Parameters for Optimization
3. Typical Scope of Supply for Skid Systems
4. Typical Applications for Biotech Centrifuges
5. CIP Approach
3/6/2008
ISPE Carolina South-Atlantic
Chapter
32
3/6/2008
ISPE Carolina South-Atlantic
Chapter
33