1. CHEE450 – Disc Stack Centrifuge
Graham Watt
Jackie Ankomah
Dilmini Peiris
Bryan Cawthorn

2. Outline Background of centrifugation – purpose
Centrifuge designs – different requirements
Disc stack centrifuge technology
Our centrifuge – process
Design choice and sizing
Costing analysis

3. Centrifugation
Downstream processing is a major consideration in industry
- separation of products/byproducts/wastes
-separation of multiple phases, liquids/solids
Specific to our application, removal of biomass from
production stream
-can be achieved through application of centripetal force
-similar principles to use of settling tank, accelerated

4. Monoclonal Antibody Production

5. General Methods for Solids Removal
Filters – low solids concentration
Disc stack centrifuge – increasing concentration
Decanter centrifuge – higher concentration

6. Choice of Disc Stack Centrifuge
Our Process
- 1% solids **
- 1micron diameter
Courtesy Alfa-Laval, 2008

7. How DSC Works
Subjecting the material to high centrifugal forces denser solids outwards
-causes separation of solid and liquids phases
-allows removal of solids manually, intermittently, or continuously
Courtesy Alfa-Laval, 2008

8. Design Considerations
Centrifugation systems are very sensitive to changes in material composition
- liquid media viscosity will impact settling rate (Stokes’ Law)
- liquid flowrate through centrifuge
- particle size (flocculation interactions)
- cell integrity
- rate limiting steps in process – fermentation of 12 days

9. Design Recommendation
Recommendation courtesy Stanley Foster, Alfa Laval
Alfa Laval Culturefuge 400
- Designed to limit cell disruption
- Hermetic seal preventing air/liquid interface
- Allows for necessary throughputs
Courtesy Elsevier, 2008

10. Design Parameters / Costing
Liquid Viscosity – 1.5cP
Particle Diameter – 1micron
Throughput – 63.7L/h
Outer disk radius m
Inner disk radius - 0.5m
Number of disks - 10
Centrifugation time - 10 days
Cost estimation - $80,000

11. Alternative DSC and their capabilities
Courtesy Alfa-Laval, 2008

12. Questions and Answers ?