CHEE450 – Disc Stack Centrifuge Graham Watt Jackie Ankomah Dilmini Peiris Bryan Cawthorn
Outline Background of centrifugation – purpose Centrifuge designs – different requirements Disc stack centrifuge technology Our centrifuge – process Design choice and sizing Costing analysis
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
Monoclonal Antibody Production
General Methods for Solids Removal Filters – low solids concentration Disc stack centrifuge – increasing concentration Decanter centrifuge – higher concentration
Choice of Disc Stack Centrifuge Our Process - 1% solids ** - 1micron diameter Courtesy Alfa-Laval, 2008
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
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
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
Design Parameters / Costing Liquid Viscosity – 1.5cP Particle Diameter – 1micron Throughput – 63.7L/h Outer disk radius - 0.75m Inner disk radius - 0.5m Number of disks - 10 Centrifugation time - 10 days Cost estimation - $80,000
Alternative DSC and their capabilities Courtesy Alfa-Laval, 2008
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