Centrifugal Separations in Biotechnology

1 Introduction

1.1 Introduction 1.2 Centrifugal Separation and Filtration 1.2.1 Sedimenting Centrifuge 1.2.2 Filtering centrifuges 1.3 Pros and Cons of Filtration versus Centrifugation 1.4 Generic Flow Sheet for Biopharmaceutical Process 1.5 Other Centrifugal Separations 1.6 Inputs and Outputs of Centrifuge 1.7 Separation Metrics 1.7.1 Protein Yield 1.7.2 Centrate Suspended Solids. 1.7.3 Throughput Rate 1.7.4 Cell Viability 1.8 Summary

2 Principles of Centrifugal Sedimentation

2.1 Introduction 2.2 Non-intuitive Phenomena 2.2.1 Pressure Distribution 2.2.2 Coriolis Effect 2.3 Intuitive Phenomena 2.3.1 Centrifugal Acceleration 2.3.2 Fluid in a Centrifuge Bowl not at Solid-Body Motion 2.3.3 Regimes of Sedimentation 2.3.4 Stokes’ Law 2.3.5 Settling with Concentrated Solids 2.4 Process Functions 2.5 Summary

3. Batch and Semi-Batch Centrifuges

3.1 Spintube 3.2 Centrifugal Filter 3.3 Ultracentrifuges 3.3.1 Analytical Ultracentrifuge 3.3.2 Preparative Ultracentrifuge 3.3.3 Centrifugal Elutriation 3.4 Tubular Centrifuge 3.4.1 General Tubular Bowl Geometry 3.4.2 Ribs and Solids Scraper 3.4.3 Plunger Cake Discharge 3.4.4 Submerged Hub 3.5 Summary

4. Disk Centrifuge

4.1 Lamella/Inclined Plate Settler 4.1.1 Inclined Plate Settler Principle 4.1.2 Complications in Inclined Plate Settler 4.2 Disk Stack Centrifuge 4.2.1 General Disk Geometry 4.2.2 Disk Angle 4.2.3 Disk Spacing 4.2.4 Process Functions of Disk Centrifuge 4.2.5 Feed Solids 4.2.6 Manual Disk Centrifuge 4.2.7 Intermittent Discharge 4.2.8 Chamber Bowl 4.2.9 Nozzle Discharge 4.2.10 Liquid Discharge 4.3 Feed Inlet and Accelerator 4.3.1 Introduction to Low Shear 4.3.2 Hydro-Hermetic Feed Design 4.3.3 Power Loss 4.3.4 Feed Acceleration Visual and Quantitative Testing 4.3.5 Improved Feed Accelerator 4.4 Other Considerations 4.5 Examples of commercial disk stack centrifuge 4.6 Summary

5 Decanter Centrifuge

5.1 Solid Bowl or Decanter centrifuge 5.2 Feed Rate 5.3 Pool Depth 5.4 Rotation Speed and G-force 5.5 Differential Speed 5.6 Sedimentation Enhancement using Chemicals 5.7 Three-Phase Separation 5.8 Cake Conveyance 5.8.1 Dry Beach 5.8.2 Hydraulic Assist 5.9 Summary  

6 Commercial Applications of Centrifugation in Biotechnology

6.1 Generic Flow Sheet of Biopharmaceutical 6.2 Mammalian Cell 6.3 Yeast Processing 6.4 Hormones Processing 6.5 Insulin Production 6.6 Biotech Separation of Inclusion Bodies 6.7 Vaccines Processing 6.7.1 Concentrated Cell based Product 6.7.2 Serum Product 6.8 Enzymes Processing 6.8.1 Extracellular Enzymes 6.8.2 Intracellular Enzymes 6.9 Ethanol Production 6.10 Other Biotech Processing 6.10.1 Recovery of Coagulation Factors from Blood Plasma 6.10.2 Tissue from Animal Cells 6.10.3 Lab Concentration and Buffer Exchange using centrifugal Filter 6.11 Summary  

7 Concentrating Solids by Centrifugation

7.1 Introduction 7.2 Concentrating underflow 7.3 Compaction 7.4 Expression or Percolation 7.5 Compaction Testing 7.6 Compaction Pressure 7.7 Recommendations for Increasing Solid Concentration in Underflow 7.8 Summary

8 Lab and Pilot Testing

8.1 Process Objectives 8.2 Solid, Liquid and Suspension Properties 8.2.1 Solids Properties 8.2.2 Mother Liquid Properties 8.2.3 Feed Slurry Properties 8.3 Bench-Scale Testing 8.3.1 Separability 8.3.2 Flocculant and Coagulant in Bench Tests 8.3.3 Test Variables 8.3.4 Material Balance 8.3.5 Acceleration and Deceleration Time Duration 8.3.6 Settling Velocity 8.4 Pilot Testing 8.4.1 Material Balance Consideration for Pilot/Production Scale 8.4.2 Product (Protein) Yield 8.4.3 Pilot Test Factors 8.5 Summary

9 Selection and Sizing of Centrifuges

9.1 Selection 9.1.1 Introduction 9.1.2 Tubular Centrifuge Selection 9.1.3 Disk Centrifuge Selection 9.1.4 Centrifuge Comparison 9.2 Centrifuge Sizing 9.2.1 Sizes and Rates 9.2.2 Dimensionless Le Number 9.2.3 Spintube (bottle) Centrifuge 9.2.4 Sizing for Disk Centrifuge 9.2.5 Sizing for Tubular, Chamber and Decanter Centrifuge 9.3 Feed Particle Size Distribution 9.4 Summary  

10 Troubleshoot and Optimization

10.1 Troubleshooting 10.1.1 Time Scale of Occurrence 10.1.2 Mechanical or Process Problem 10.1.3 Process Problems 10.1.4 Mechanical Problem 10.2 Optimization 10.2.1 Separation Metrics 10.2.2 Monitored Variables 10.2.3 Controlled Variables 10.2.4 A Simple Optimization Scheme 10.3 Summary 

11 Flow Visualization and Separation Modeling of Tubular Centrifuge

11.1 Flow Visualization 11.2 Improved Moving Layer Flow Model 11.3 Effect of Velocity Profile 11.4 Effect of Friction within the Flow Layer 11.5 Dimensionless Le Parameter 11.6 Quantitative Prediction 11.6.1 Total Solids Recovery in Cake 11.6.2 Total solids Recovery in the Centrate 11.6.3 Particle Size Distribution of Supernatant/Overflow 11.6.4 Cumulative Size Recovery 11.7 Sedimentation Tests 11.7.1 Experiments on Sedimentation in Rotating Bowl Centrifuge 11.8 Summary  

12 Disk Stack Modeling

12.1 Disk Model 12.1.1 Continuous Phase 12.1.2 Dispersed Phase 12.2 Model Validation 12.3 Complications 12.4 Summary  

13 Performance Projection of Centrifuges in Bioseparation

13.1 Disk Centrifuge 13.1.1 Baseline Case (400-mm Disk) 13.1.2 Effect of Fine Size Distribution (400-mm Disk) 13.1.3 Effect of G-Force (580-mm disk) 13.1.4 Effect of Efficiency h (580-mm Disk) 13.1.5 Disk Centrifuge for Yeast Processing (500-mm disk) 13.1.6 Disk Centrifuge for Inclusion Body Separation (260-mm Disk) 13.1.7 Enzymes (580-mm Disk) 13.2 Tubular Centrifuge 13.2.1 High-G Tubular (100- & 300-mm) 13.2.2 Lower-G Tubular (100- & 300-mm) 13.3 Decanter 13.4 Spintube 13.5 Strategy of Developing Drug using Numerical Simulations 13.6 Summary  

14 Rotating Membrane in Bioseparation

14.1 Membrane 14.1.1 Osmotic Pressure Resistance 14.1.2 Gel Resistance 14.1.3 Membrane Fouling and Cake Formation 14.1.4 Two Scenarios of Rotational Effect on Membrane Filtration 14.2 Rotating Disk Membrane with surface parallel to the G-Force 14.2.1 Dimensionless Numbers 14.2.2 Governing Equations and Solution 14.2.3 Gel Concentration 14.2.4 Determining Diffusivity 14.2.5 Parametric Effects 14.3 Rotating Membrane with Membrane Perpendicular to the G-Force 14.3.1 Spintube Equipped with Membrane Module - Centrifugal Filter 14.3.2 Model on Swinging Bucket Equipped with UF Membrane 14.3.3 Comparing Test Results with Predictions 14.4 Summary