Graham Watt

Jackie Ankomah

Dilmini Peiris

Bryan Cawthorn

CHEE450 – Disc Stack Centrifuge

OutlineBackground of centrifugation – purpose

Centrifuge designs – different requirements

Disc stack centrifuge technology

Our centrifuge – process

Design choice and sizing

Costing analysis

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

Centrifugation

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

Courtesy Alfa-Laval, 2008

Our Process - 1% solids **- 1micron diameter

How DSC WorksSubjecting 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 ConsiderationsCentrifugation 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 / CostingLiquid 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

Questions and Answers

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