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Agitator Design for Gas-Liquid Fermenters and Bioreactors

1. Aufl.

von: Gregory T. Benz
131,99 €
Verlag:	Wiley
Format:	PDF
Veröffentl.:	05.03.2021
ISBN/EAN:	9781119650508
Sprache:	englisch
Anzahl Seiten:	448

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Titelbeschreibung

AGITATOR DESIGN FOR GAS-LIQUID FERMENTERS AND BIOREACTORS Explore the basic principles and concepts of the design of agitation systems for fermenters and bioreactorsAgitator Design for Gas-Liquid Fermenters and Bioreactors delivers a concise treatment and explanation of how to design mechanically sound agitation systems that will perform the agitation process function efficiently and economically. The book covers agitator fundamentals, impeller systems, optimum power and air flow at peak mass transfer calculations, optimizing operation for minimum energy per batch, heat transfer surfaces and calculations, shaft seal considerations, mounting methods, mechanical design, and vendor evaluation.The accomplished author has created a practical and hands-on tool that discusses the subject of agitation systems from first principles all the way to implementation in the real world. Step-by-step processes are included throughout the book to assist engineers, chemists, and other scientists in the design, construction, installation, and maintenance of these systems.Readers will also benefit from the inclusion of:<li><bl>A thorough introduction to the design of gas-liquid fermenters and bioreactors</bl></li><li><bl>An exploration of agitator fundamentals, impeller systems, optimum power, and air flow at peak mass transfer calculations</bl></li><li><bl>A discussion of how to optimize operation for minimum energy per batch</bl></li><li><bl>Step-by-step processes to assist engineers, chemists, and scientists</bl></li><li><bl>An examination of heat transfer surfaces and calculations, shaft seal considerations, mounting methods, and mechanical design</bl></li>Perfect for chemical engineers, mechanical engineers, process engineers, chemists, and materials scientists, Agitator Design for Gas-Liquid Fermenters and Bioreactors will also earn a place in the libraries of pharmaceutical scientists seeking a one-stop resource for designing mechanically sound agitation systems.

Inhaltsverzeichnis

Preface xix Foreword xxi Foreword for Greg Benz xxiii 1 Purpose of Agitator Design 1 References 2 2 Major Steps in Successful Agitator Design 3 Define Process Results 3 Define Process Conditions 5 Choose Tank Geometry 6 Calculate Equivalent Power/Airflow Combinations for Equal Mass Transfer Rate 7 Choose Minimum Combined Power 7 Choose Shaft Speed; Size Impeller System to Draw Required Gassed Power 7 Decision Point: D/T and Gassing Factors OK? 8 Mechanical Design 8 Decision Point: Is the Mechanical Design Feasible? 8 Repeat to Find Lowest Cost 8 Repeat for Different Aspect Ratios 9 Repeat for Different Process Conditions 9 Finish 9 Summary of Chapter 10 List of Symbols 10 References 10 3 Agitator Fundamentals 11 Agitated Tank Terminology 11 Prime Mover 11 Reducer 13 Shaft Seal 13 Wetted Parts 13 Tank Dimensions 14 How Agitation Parameters Are Calculated 14 Reynolds Number 15 Power Number 16 Pumping Number 17 Dimensionless Blend Time 17 Aeration Number 18 Gassing Factor 18 Nusselt Number 18 Froude Number 19 Prandtl Number 19 Geometric Ratios 20 Baffle Number 20 Dimensionless Hydraulic Force 20 Thrust Number 21 Typical Dimensionless Number Curves 21 A Primer on Rheology 25 Newtonian Model 26 Pseudoplastic or Shear Thinning, Model (Aka Power Law Fluid) 27 Bingham Plastic 27 Herschel–Bulkley 27 Impeller Apparent Viscosity 29 A Bit of Impeller Physics 29 Summary of Chapter 31 List of Symbols 31 Greek Letters 32 References 32 4 Agitator Behavior under Gassed Conditions 35 Flooding 35 Kla Method 35 Power Draw Method 36 Visual Flow Pattern Method 37 Effect on Power Draw 38 Holdup 39 Example of Holdup Calculation 40 Holdup “War Story” 40 Variable Gas Flow Operation 40 Mechanical Effects 42 Summary of Chapter 42 List of Symbols 42 References 43 5 Impeller Types Used in Fermenters 45 Impeller Flow Patterns 45 Axial Flow 46 Radial Flow 47 Mixed Flow 47 Chaos Flow 48 Examples of Axial Flow Impellers 49 Low Solidity 49 High Solidity 52 Up-pumping vs. Down Pumping 55 Examples of Radial Flow Impellers 56 Straight Blade Impeller 56 Disc, aka Rushton, Turbines 57 Smith Turbines 62 CD-6 Turbine by Chemineer; aka Smith Turbine by Many Manufacturers 62 Deeply Concave Turbines 66 Deep Asymmetric Concave Turbine with Overhang (BT-6) 68 Examples of Mixed Flow Impellers 73 Examples of Chaos Impellers 74 Shear Effects 76 Specialty Impellers 78 Summary of Chapter 80 List of Symbols 80 References 81 6 Impeller Systems 83 Why Do We Need a System? 83 Reaction Engineering 83 Fermenter History 84 Steps to Impeller System Design 85 Choose Number of Impellers 86 Choose Placement of Impellers 86 Choose Type(s) of Impellers 87 Choose Power Split or Distribution Among Impellers 93 Choose D/T and/or Shaft Speed 93 D/T Effects with Variable Gas Flowrates 96 Conclusions on D/T Ratio 98 Design to Minimize Shear Damage 99 Sparger Design 100 Ring Sparger 100 Pre-dispersion 103 Fine Bubble Diffuser 104 Summary of Chapter 105 List of Symbols 106 References 106 7 Piloting for Mass Transfer 109 Why Pilot for Mass Transfer 109 Methods for Determining kla 112 Sulfite Method 112 Dynamic Method; aka Dynamic Gassing/Degassing Method 112 Steady-State Method; aka Mass Balance Method 113 Combined Dynamic and Steady-State Method 114 Equipment Needed for Scalable Data 114 Data Gathering Needs 120 Experimental Protocol 121 Summary of Chapter 128 List of Symbols 128 References 129 8 Power and Gas Flow Design and Optimization 131 What This Chapter Is about 131 Where We Are in Terms of Design 131 Design with no Data 131 Design with Limited Pilot Data 133 Design with Full Data 135 Choose Minimum Combined Power 136 State of Design Completion 141 Additional Considerations 142 Summary of Chapter 142 List of Symbols 142 References 142 9 Optimizing Operation for Minimum Energy Consumption per Batch 145 Purpose of This Chapter 145 Prerequisite 145 Conceptual Overview 145 Detailed Procedure 146 Minimizing Total Energy Usage 150 Practical Design 150 Additional Considerations 150 Summary of Chapter 152 List of Symbols 152 References 153 10 Heat Transfer Surfaces and Calculations 155 Purpose of This Chapter 155 Design Philosophy 155 Overview of the Problem 156 Heat Sources 156 Cooling Sources 157 Heat Exchange Surface Overview 158 Principle of Heat Transfer Calculation 164 Calculations By Type of Surface 166 Vessel Jacket, Agitated Side 166 Simple Unbaffled Jacket, Jacket Side 167 Dimple Jacket, Jacket Side 167 Half-Pipe Coil, Jacket Side 169 Helical Coil, Inside 171 Helical Coil, Process Side 171 Vertical Tube Bundle, Inside 173 Vertical Tube Bundle, Process Side 174 Plate Coil, Inside 175 Plate Coil, Process Side 176 Example Problem: Vertical Tube Bundle 176 Problem Statement 176 Problem Solution 177 Additional Consideration: Effect on Power Draw 182 Additional Consideration: Forces on Heat Exchange Surfaces Used as Baffles 183 Additional Consideration: Wall Viscosity 184 Additional Consideration: Effect of Gas 185 External Heat Exchange Loops 186 Summary of Chapter 187 List of Symbols 187 References 189 Further Readings 189 11 Gasses Other Than Air and Liquids Other Than Water 191 General Principle 191 Comments on Some Specific Gasses 191 Ammonia 191 Carbon Dioxide 192 Carbon Monoxide 192 Hydrogen 192 Methane 192 Oxygen 192 Economic Factors 192 Disposal Factors 193 Effects of Different Gasses on kla 193 Effects of Different Gasses on Driving Force 195 Operating Condition Effects 195 Constraints on Outlet Concentration 196 Safety 196 Liquids Other Than Water 198 Summary of Chapter 198 List of Symbols 198 References 199 12 Viscous Fermentation 201 General Background 201 Sources of Viscosity 201 Viscosity Models for Broths 202 Effect of Viscosity on Power Draw 203 Example Problem 204 Example Problem Answer 204 Effect of Viscosity on kla 205 Effect of Viscosity on Holdup 207 Effect of Viscosity on Blend Time 207 Effect of Viscosity on Flooding 209 Caverns 209 Estimating Cavern Size 211 Xanthan and Gellan Gums 212 Viscosity Models for Gums 213 Installation Survey 214 Effect of D/T and No. and Type of Impellers on Results in Xanthan Gum 217 Production Curve 218 Heat Transfer 218 All-Axial Impeller Design 218 Invisible Draft Tube vs. Axial/Radial Combination 222 Mycelial Broths 223 Typical Viscosity Model 224 Morphology Effects 224 Recommendations 225 Summary of Chapter 227 List of Symbols 227 References 228 13 Three Phase Fermentation 231 General Problem 231 Effect on Mass Transfer 231 Effect on Foam 233 Emulsion vs. Suspension 233 Complexity: How to Optimize Operation 233 Summary of Chapter 234 List of Symbols 234 References 234 14 Use of CFD in Fermenter Design 237 Purpose of This Chapter 237 Basic Theory 237 Methods of Presenting Data 239 Velocity Distribution 240 Cavern Formation 240 Blending Progress 242 Flow Around Coils 245 Bubble Size, kla, Holdup 247 DO Distribution 248 Summary of Chapter 250 List of Symbols 250 References 250 15 Agitator Seal Design Considerations 251 Introduction 251 Terminology 251 Main Functions of Fermenter Shaft Seals 252 Common Types of Shaft Seals 254 Material Considerations 265 Methods of Lubricating Seals 267 Seal Environmental Control and Seal Support System 267 Seal Life Expectations 272 Special Process Considerations 272 Summary of Chapter 275 Reference 275 16 Fermenter Agitator Mounting Methods 277 Introduction 277 Top Entering Methods 277 Direct Nozzle Mount 278 Beam Gear Drive Mount with Auxiliary Packing or Lip Seal; Beams Tied into Vessel Sidewall 281 Beam Gear Drive Mount with Auxiliary Mechanical Seal; Beams Tied into Vessel Sidewall 283 Beam Gear Drive Mount with Auxiliary Mechanical Seal; Beams Tied into Building Structure 284 Complete Drive and Seal Mount to Beams Tied into Vessel Sidewall, with Bellows Connector 285 Complete Drive and Seal Mount to Beams Tied into Building Structure, with Bellows Connector 287 Bottom Entering Methods 287 Direct Nozzle Mount 288 Floor Gear Drive Mount with Auxiliary Packing or Lip Seal 288 Floor Gear Drive Mount with Auxiliary Mechanical Seal 289 Floor Integrated Drive and Seal Mount with Bellows Connector 291 Summary of Chapter 292 References 292 17 Mechanical Design of Fermenter Agitators 293 Introduction 293 Impeller Design Philosophy 294 Discussion on Hydraulic Force 295 Shaft Design Philosophy 297 Shaft Design Based on Stress 298 Simple Example Problem 302 Sample Problem with Steady Bearing 304 Shaft Design Based On Critical Speed 304 Cantilevered Designs 306 Example Problem 308 Units with Steady Bearings 311 Solid Shaft vs. Hollow Shaft 315 Role of FEA in Overall Shaft Design-Simplified Discussion 319 Agitator Gear Drive Selection Concepts 319 Early History 320 Loads Imposed 320 Handle or Isolate Loads? 323 Handle Loads Option 1: Oversized Commercial Gear Drive 323 Handle Loads Option 2: Purpose-Built Agitator Drive 324 Isolate Loads Option 1: Hollow Quill Integrated Drive with Flexibly Coupled Extension Shaft 325 Isolate Loads Option 2: Outboard Support Bearing Module 328 Bearing Life Considerations 329 Noise Considerations 330 Torsional Natural Frequency 332 Important or Useful Mechanical Design Features 332 Summary of Chapter 333 List of Symbols 333 Greek Letters 334 References 334 18 Sanitary Design 335 Introduction 335 Definitions 336 Construction Principles 336 Wetted Parts Construction Methods 336 Welded Construction 336 In-Tank Couplings 338 Mounting Flange Area 341 Axial Impellers 344 Radial Impellers 345 Bolts and Nuts 347 Steady Bearings 348 Use of Castings, 3-D Printing 349 Polishing Methods and Measures1: Polishing vs. Burnishing 350 Polishing Methods and Measures2: Lay 351 Polishing Methods and Measures3: Roughness Average 353 Electropolish 355 Passivating 357 Effect on Mechanical Design 357 Summary of Chapter 357 Additional Sources of Information 358 List of Symbols 358 References 358 19 Aspect Ratio 359 Acknowledgment 359 Definition and Illustration of Aspect Ratio 359 What Is the Optimum Aspect Ratio? 360 Effects of Z/T on Cost and Performance at a Given Working Volume 361 Vessel Cost 361 Agitator Shaft Design Difficulty 361 Power Required for Mass Transfer 361 Agitator Cost 362 Airflow Requirements 362 Compressor Power 362 DO Uniformity 362 Heat Transfer Capability 363 Real Estate/Land Usage Issues 363 Building Codes; Noise 363 Illustrative Problem Number 1 363 Vessel Dimensions 364 Airflow and Power 366 Heat Transfer Data and Assumptions 367 Heat Transfer Results 369 Blend Time, DO Uniformity 371 Capital Cost (Agitator Plus Vessel Only) 372 Other Operating Costs 372 So What Is the Optimum Aspect Ratio for This Problem? 373 Illustrative Problem Number 2 373 Illustrative Problem Number 3 376 Summary of Chapter 380 List of Symbols 381 References 381 20 Vendor Evaluation 383 Product Considerations 383 Gear Drive Ruggedness 384 Design Technology 384 Impeller Selection 384 Shaft Design 385 Company Considerations 385 Reputation with Customers 385 Company Size 386 Years in Business 386 Years Under New Ownership 386 Employee Turnover 387 Vertical Integration 387 R&D Program and Publications 388 Depth of Application Engineering 389 Testing Laboratory 389 ISO Certification (Necessary vs Sufficient) 391 Quality Control Program (Not Lot Sample; 100%) 391 Rep vs Direct Sales (a Good Rep Annoys the Manufacturer) 392 Service Capability 393 Typical Delivery Times and Performance 393 Parts Availability 394 Price (Least Important) 395 Willingness to Work with Consultants 395 Vendor Audit Checklist 396 Use of an Outside Consultant 397 Summary of Chapter 399 List of Symbols 399 References 400 A. Appendix to Chapter 20 400 21 International Practices 401 Introduction 401 North America 401 Vendors 401 Design Practices 402 Selling/Buying Practices 402 Degree of Vertical Integration 403 Role of Design Firms 403 R&D 404 Culture 404 EU 405 Vendors 405 Design Practices 405 Selling/Buying Practices 405 Degree of Vertical Integration 406 Role of Design Firms 406 R&D 406 Culture 407 Japan 407 Vendors 407 Design Practices 407 Selling/Buying Practices 407 Degree of Vertical Integration 408 Role of Design Firms 408 R&D 408 Culture 408 China 409 Vendors 409 Design Practices 409 Selling/Buying Practices 411 Degree of Vertical Integration 412 Role of Design Firms 412 R&D 412 Culture 413 Summary of Chapter 413 Cultural Resources 413 Afterword 415 Index 417

Autorenportrait

Gregory T. Benz, P.E., is the President of Benz Technology International, an engineering consulting firm and Chinese business development corporation. He has authored numerous articles, conducted more than 50 seminars, and holds a patent on a nonrotating, nonseal method of mechanically agitating tanks.

Back cover copy

Explore the basic principles and concepts of the design of agitation systems for fermenters and bioreactorsAgitator Design for Gas-Liquid Fermenters and Bioreactors delivers a concise treatment and explanation of how to design mechanically sound agitation systems that will perform the agitation process function efficiently and economically. The book covers agitator fundamentals, impeller systems, optimum power and air flow at peak mass transfer calculations, optimizing operation for minimum energy per batch, heat transfer surfaces and calculations, shaft seal considerations, mounting methods, mechanical design, and vendor evaluation.The accomplished author has created a practical and hands-on tool that discusses the subject of agitation systems from first principles all the way to implementation in the real world. Step-by-step processes are included throughout the book to assist engineers, chemists, and other scientists in the design, construction, installation, and maintenance of these systems.Readers will also benefit from the inclusion of:<li><bl>A thorough introduction to the design of gas-liquid fermenters and bioreactors</bl></li><li><bl>An exploration of agitator fundamentals, impeller systems, optimum power, and air flow at peak mass transfer calculations</bl></li><li><bl>A discussion of how to optimize operation for minimum energy per batch</bl></li><li><bl>Step-by-step processes to assist engineers, chemists, and scientists</bl></li><li><bl>An examination of heat transfer surfaces and calculations, shaft seal considerations, mounting methods, and mechanical design</bl></li>Perfect for chemical engineers, mechanical engineers, process engineers, chemists, and materials scientists, Agitator Design for Gas-Liquid Fermenters and Bioreactors will also earn a place in the libraries of pharmaceutical scientists seeking a one-stop resource for designing mechanically sound agitation systems.