Table of Contents 1
Cover
5
Preface
6
Foreword
8
1 Purpose of Agitator Design
References
9
2 Major Steps in Successful Agitator Design
Define Process Results
Define Process Conditions
Choose Tank Geometry
Calculate Equivalent Power/Airflow Combinations for Equal Mass Transfer Rate
Choose Minimum Combined Power
Choose Shaft Speed; Size Impeller System to Draw Required Gassed Power
Decision Point: D/T and Gassing Factors OK?
Mechanical Design
Decision Point: Is the Mechanical Design Feasible?
Repeat to Find Lowest Cost
Repeat for Different Aspect Ratios
Repeat for Different Process Conditions
Finish
Summary of Chapter
References
10
3 Agitator Fundamentals
Agitated Tank Terminology
Prime Mover
Reducer
Shaft Seal
Wetted Parts
Tank Dimensions
How Agitation Parameters Are Calculated
Reynolds Number
Power Number
Pumping Number
Dimensionless Blend Time
Aeration Number
Gassing Factor
Nusselt Number
Froude Number
Prandtl Number
Geometric Ratios
Baffle Number
Dimensionless Hydraulic Force
Thrust Number
Typical Dimensionless Number Curves
A Primer on Rheology
Newtonian Model
Pseudoplastic or Shear Thinning, Model (Aka Power Law Fluid)
Bingham Plastic
Herschel–Bulkley
Impeller Apparent Viscosity
A Bit of Impeller Physics
Summary of Chapter
References
11
4 Agitator Behavior under Gassed Conditions
Flooding
kla Method
Power Draw Method
Visual Flow Pattern Method
Effect on Power Draw
Holdup
Example of Holdup Calculation
Holdup “War Story”
Variable Gas Flow Operation
Mechanical Effects
Summary of Chapter
References
12
5 Impeller Types Used in Fermenters
Impeller Flow Patterns
Examples of Axial Flow Impellers
Examples of Radial Flow Impellers
Examples of Mixed Flow Impellers
Examples