Guide Compressor Tech 2e

ISBN-13: 9780471727934 / Angielski / Twarda / 2006 / 590 str.

Heinz P. Bloch

Opis

A Complete overview of theory, selection, design, operation, and maintenance This text offers a thorough overview of the operating characteristics, efficiencies, design features, troubleshooting, and maintenance of dynamic and positive displacement process gas compressors. The author examines a wide spectrum of compressors used in heavy process industries, with an emphasis on improving reliability and avoiding failure. Readers learn both the theory underlying compressors as well as the myriad day-to-day practical issues and challenges that chemical engineers and plant operation personnel must address. The text features:

• Latest design and manufacturing details of dynamic and positive displacement process gas compressors
• Examination of the full range of machines available for the heavy process industries
• Thorough presentation of the arrangements, material composition, and basic laws governing the design of all important process gas compressors
• Guidance on selecting optimum compressor configurations, controls, components, and auxiliaries to maximize reliability
• Monitoring and performance analysis for optimal machinery condition
• Systematic methods to avoid failure through the application of field-tested reliability enhancement concepts
• Fluid instability and externally pressurized bearings
• Reliability-driven asset management strategies for compressors
• Upstream separator and filter issues

The text's structure is carefully designed to build knowledge and skills by starting with key principles and then moving to more advanced material. Hundreds of photos depicting various types of compressors, components, and processes are provided throughout. Compressors often represent a multi-million dollar investment for such applications as petrochemical processing and refining, refrigeration, pipeline transport, and turbochargers and superchargers for internal combustion engines. This text enables the broad range of engineers and plant managers who work with these compressors to make the most of the investment by leading them to the best decisions for selecting, operating, upgrading, maintaining, and troubleshooting.

Spis treści

PREFACE xiii

ACKNOWLEDGMENTS xv

PART I POSITIVE DISPLACEMENT COMPRESSOR TECHNOLOGY 1

1 Theory 3

1.1 Symbols 3

1.2 How a Compressor Works 4

1.3 First Law of Thermodynamics 8

1.4 Second Law of Thermodynamics 8

1.5 Ideal or Perfect Gas Laws 9

1.5.1 Boyle s Law 9

1.5.2 Charles Law 9

1.5.3 Amonton s Law 9

1.5.4 Dalton s Law 9

1.5.5 Amagat s Law 10

1.5.6 Avogadro s Law 10

1.5.7 Perfect Gas Formula 10

1.6 Vapor Pressure 11

1.7 Gas and Vapor 11

1.8 Partial Pressures 11

1.9 Critical Conditions 13

1.10 Compressibility 13

1.11 Generalized Compressibility Charts 14

1.12 Gas Mixtures 15

1.13 The Mole 15

1.14 Specific Volume and Density 16

1.15 Volume Percent of Constituents 16

1.16 Molecular Weight of a Mixture 16

1.17 Specific Gravity and Partial Pressure 17

1.18 Ratio of Specific Heats 17

1.19 Pseudo–critical Conditions and Compressibility 18

1.20 Weight–Basis Items 18

1.21 Compression Cycles 19

1.22 Power Requirement 20

1.23 Compressibility Correction 21

1.24 Multiple Staging 22

1.25 Volume References 23

1.26 Cylinder Clearance and Volumetric Efficiency 24

1.27 Cylinder Clearance and Compression Efficiency 27

Reference 27

2 Reciprocating Process Compressor Design Overview 29

2.1 Crankshaft Design 33

2.2 Bearings and Lubrication Systems 37

2.3 Connecting Rods 37

2.4 Crossheads 38

2.5 Frames and Cylinders 39

2.6 Cooling Provisions 45

2.7 Pistons 47

2.8 Piston and Rider Rings 47

2.9 Valves 48

2.10 Piston Rods 51

2.11 Packings 55

2.12 Cylinder Lubrication 55

2.13 Distance Pieces 56

2.14 Reciprocating Compressor Modernization 57

2.14.1 Cylinder Upgrades 59

2.14.2 Design for Easy Maintenance 59

2.14.3 Crosshead Designs and Attention to Reliable Lubrication 61

2.14.4 Materials 62

3 Reciprocating Compressor Performance and Monitoring Considerations 63

3.1 Capacity Control 63

3.1.1 Recycle or Bypass 64

3.1.2 Suction Throttling 64

3.1.3 Suction Valve Unloading 65

3.1.4 Clearance Pockets 67

3.2 More About Cylinder Jacket Cooling and Heating Arrangements 70

3.2.1 Methods of Cooling 71

3.3 Comparing Lubricated and Nonlubricated Conventional Cylinder Construction 73

3.3.1 Lubricated Cylinder Designs 73

3.3.2 Nonlubricated Cylinder Design 75

3.4 Compressor Vent and Buffer Systems 76

3.5 Compressor Instrumentation 77

3.5.1 Electric vs. Pneumatic Switches 82

3.5.2 Switch Set Points 82

3.5.3 Control Panels 82

3.5.4 Valve–in–Piston Reciprocating Compressors 83

3.5.5 Barrel–Frame Reciprocating Compressors 84

3.6 Condition Monitoring of Reciprocating Compressors 85

3.6.1 Maintenance Strategies 86

3.6.2 Justification for Machine Monitoring 86

3.6.3 What to Monitor and Why 87

References 97

4 Labyrinth Piston Compressors 99

4.1 Main Design Features 99

4.2 Energy Consumption 101

4.3 Sealing Problems 104

5 Hypercompressors 109

5.1 Introduction 109

5.2 Cylinders and Piston Seals 111

5.3 Cylinder Heads and Valves 115

5.4 Drive Mechanism 117

5.5 Miscellaneous Problems 119

5.6 Conclusions 120

6 Metal Diaphragm Compressors 121

6.1 Introduction 121

6.2 Terminology 121

6.3 Description 122

7 Lobe and Sliding Vane Compressors 129

8 Liquid Ring Compressors 135

9 Rotary Screw Compressors and Filter Separators 141

9.1 Twin–Screw Machines 141

9.1.1 Working Phases 141

9.1.2 Areas of Application 145

9.1.3 Dry vs. Liquid–Injected Machines 145

9.1.4 Operating Principles 145

9.1.5 Flow Calculation 147

9.1.6 Power Calculation 147

9.1.7 Temperature Rise 150

9.1.8 Capacity Control 150

9.1.9 Mechanical Construction 153

9.1.10 Industry Experience 154

9.1.11 Maintenance History 158

9.1.12 Performance Summary 158

9.2 Oil–Flooded Single–Screw Compressors 160

9.3 Selecting Modern Reverse–Flow Filter–Separator Technology 163

9.3.1 Conventional Filter–Separators vs. SCCs 164

9.3.2 Removal Efficiencies 165

9.3.3 Filter Quality 165

9.3.4 Selecting the Most Suitable Gas Filtration Equipment 166

9.3.5 Evaluating the Proposed Configurations 167

9.3.6 Life–Cycle–Cost Calculations 168

9.3.7 Conclusions 169

10 Reciprocating Compressor Performance and Sizing Fundamentals 171

10.1 Theoretical Maximum Capacity 172

10.2 Capacity Losses 173

10.3 Valve Preload 174

10.4 Valve and Gas Passage Throttling 174

10.5 Piston Ring Leakage 176

10.6 Packing Leakage 177

10.7 Discharge Valve Leakage 177

10.8 Suction Valve Leakage 178

10.9 Heating Effects 178

10.10 Pulsation Effects 180

10.11 Horsepower 181

10.12 Horsepower Adders 181

10.13 Gas Properties 182

10.13.1 Ideal Gas 182

10.13.2 Real Gas 182

10.14 Alternative Equations of State 183

10.15 Condensation 183

10.16 Frame Loads 183

10.17 Compressor Displacement and Clearance 184

10.18 Staging 186

10.19 Fundamentals of Sizing 187

10.19.1 Number of Stages 187

10.19.2 Approximate Horsepower 187

10.19.3 Cylinder Bore Requirements 188

10.19.4 Frame Load 188

10.19.5 Vendor Confirmation 189

10.20 Sizing Examples 189

PART II DYNAMIC COMPRESSOR TECHNOLOGY 197

11 Simplified Equations for Determining the Performance of Dynamic Compressors 205

11.1 Nonoverloading Characteristics of Centrifugal Compressors 205

11.2 Stability 205

11.3 Speed Change 207

11.4 Compressor Drive 207

11.5 Calculations 208

12 Design Considerations and Manufacturing Techniques 215

12.1 Axially vs. Radially Split 215

12.2 Tightness 215

12.3 Material Stress 215

12.4 Nozzle Location and Maintenance 216

12.5 Design Overview 217

12.5.1 Casings 217

12.5.2 Flow Path 230

12.5.3 Rotors 234

12.5.4 Impellers 234

12.5.5 Axial Blading 242

12.5.6 Seals 242

12.6 Bearing Configurations 250

12.6.1 Radial Bearings 250

12.6.2 Thrust Bearings 251

12.6.3 Flexure Pivot Tilt Pad Bearings 253

12.7 Casing Design Criteria 257

12.8 Casing Manufacturing Techniques 265

12.9 Stage Design Considerations 273

12.10 Impeller Manufacturing Techniques 282

12.11 Rotor Dynamic Considerations 286

12.12 Fouling Considerations and Coatings 292

12.12.1 Polymerization and Fouling 292

12.12.2 Fouling and Its Effect on Compressor Operation 293

12.12.3 Coating Case Study 294

12.12.4 SermaLon Coating 296

12.12.5 Results 297

13 Advanced Sealing and Bearing Systems 299

13.1 Background 299

13.2 Dry Seals 300

13.2.1 Operating Principles 300

13.2.2 Operating Experience 302

13.2.3 Problems and Solutions 303

13.2.4 Dry Seal Upgrade Developments 304

13.2.5 Dry Gas Seal Failures Avoided by Gas Conditioning 304

13.3 Magnetic Bearings 308

13.3.1 Operating Principles 308

13.3.2 Operating Experience and Benefits 310

13.3.3 Problems and Solutions 311

13.4 Development Efforts 311

13.4.1 Thrust–Reducing Seals 312

13.5 Integrated Designs 314

13.6 Fluid–Induced Instability and Externally Pressurized Bearings 318

13.6.1 Instability Considerations 318

13.6.2 Fluid–Induced Instability 318

13.6.3 Eccentricity and Stiffness 320

13.6.4 Externally Pressurized Bearings and Seals 321

13.6.5 Practical Applications 324

13.6.6 Rotor Model, Dynamic Stiffness, and Fluid Instability 325

13.6.7 Root Locus Stability Analysis 327

13.6.8 More About Externally Pressurized Bearings 328

13.6.9 Field Data Collection 331

13.6.10 Test Stand Data 334

13.6.11 Conclusions 336

References 336

Suggested Reading 336

14 Couplings, Torque Transmission, and Torque Sensing 339

14.1 Coupling Overview 339

14.1.1 Low Overhung Moment 341

14.1.2 Low Residual Unbalance Desired 343

14.1.3 Long Life and Maintainability 344

14.1.4 Continuous Lubrication Not a Cure–All 345

14.1.5 Contoured Diaphragm Coupling 345

14.2 Coupling Retrofits and Upgrades 347

14.3 Performance Optimization Through Torque Monitoring 349

15 Lubrication, Sealing, and Control Oil Systems for Turbomachinery 357

15.1 Considerations Common to All Systems 357

15.2 Seal Oil Considerations 359

16 Compressor Control 363

16.1 Introduction 363

16.2 Control System Objectives 363

16.3 Compressor Maps 364

16.3.1 Invariant Coordinates 366

16.4 Performance Control 368

16.4.1 PI and PID Control Algorithms 370

16.4.2 Stability Considerations 372

16.4.3 Integral or Reset Windup 373

16.5 Performance Limitations 373

16.5.1 Surge Limit 374

16.5.2 Stonewall 375

16.6 Preventing Surge 376

16.6.1 Antisurge Control Variables 376

16.6.2 Antisurge Control Algorithms 378

16.6.3 Controlling Limiting Variables 378

16.7 Loop Decoupling 379

16.8 Conclusions 380

Reference 380

17 Head–Flow Curve Shape of Centrifugal Compressors 381

17.1 Compressor Stage 381

17.2 Elements of the Characteristic Shape 382

17.2.1 Basic Slope 382

17.2.2 Blade Angle 384

17.2.3 Fan Law Effect 385

17.2.4 Choke Effect 386

17.2.5 Mach Number 387

17.2.6 Significance of Gas Weight 387

17.2.7 Inducer Impeller Effects on Head Output 388

17.2.8 Surge 389

17.2.9 Vaned Diffusers 390

17.2.10 Vaneless Diffusers 390

17.2.11 Equivalent Tip Speeds 391

17.3 Conclusions 393

18 Use of Multiple–Inlet Compressors 395

18.1 Critical Selection Criteria 395

18.1.1 Head Rise to Surge, Surge Margin, and Overload Margin 396

18.1.2 Head per Section 397

18.1.3 Compressor Parasitic Flows 398

18.1.4 Excess Margins on Other Process Equipment 399

18.1.5 Representing Compressor Performance 399

18.1.6 Practical Levels of Critical Operating Parameters 399

18.2 Design of a Sideload Compressor 401

18.2.1 Mixing Area 402

18.2.2 Aerodynamics 403

18.2.3 Temperature Stratification 405

18.3 Testing 405

18.3.1 Test Setup 406

18.3.2 Instrumentation 406

18.3.3 Testing Procedure 406

18.3.4 Accuracy of Test Results 407

18.3.5 Evaluation of Results 407

19 Compressor Performance Testing 409

19.1 Performance Testing of New Compressors 409

19.1.1 Re–rate Options 410

19.1.2 General Guidelines 410

19.1.3 Gas Sampling 411

19.1.4 Instrumentation 412

19.1.5 Sideload Compressors 414

19.1.6 Calculation Procedures 416

19.2 Shop Testing and Types of Tests 418

19.3 Field Testing 420

19.4 Predicting Compressor Performance at Other Than As–Designed Conditions 432

19.4.1 How Performance Tests Are Documented 434

19.4.2 Design Parameters: What Affects Performance 434

19.4.3 What to Seek from Vendors Documents 435

19.4.4 Illustrations and Example 436

References 441

20 Procurement, Audit, and Asset Management Decisions 443

20.1 Incentives to Buy from Knowledgeable and Cooperative Compressor Vendors 443

20.2 Industry Standards and Their Purpose 444

20.2.1 Typical Scope of Standards 444

20.2.2 Disclaimers in Standards 447

20.2.3 Going Beyond the Standards 447

20.3 Disadvantages of Cheap Process Compressors 448

20.4 Audits vs. Reviews 449

20.4.1 Staffing and Timing of Audits and Reviews 450

20.4.2 Use of Equipment Downtime Statistics 450

20.5 Auditing and Reviewing Compressors 451

20.6 Compressor Inspection: Extension of the Audit Effort 465

20.6.1 Inspection of a Welded Impeller (Wheel) and the Entire Rotor 466

20.7 Compressor Installation Specifications 474

20.7.1 Field Erection and Installation Specifications for Special–Purpose Machinery 475

References 476

21 Reliability–Driven Asset Management Strategies 477

21.1 Strategy for Reciprocating Compressors 477

21.1.1 Process Operating Window 478

21.1.2 Breakdown Maintenance 478

21.1.3 Time–Based Maintenance 478

21.1.4 Equipment Health Monitoring 479

21.1.5 Reliability and Maintenance 479

21.1.6 Asset Management Strategy 479

21.2 Achieving Compressor Asset Optimization 486

21.2.1 Input Obtained from Workshops 486

21.2.2 Conclusions 496

References 497

APPENDIX A PROPERTIES OF COMMON GASES 499

APPENDIX B SHORTCUT CALCULATIONS AND GRAPHICAL 507

COMPRESSOR SELECTION PROCEDURES

APPENDIX C BIBLIOGRAPHY AND LIST OF CONTRIBUTORS 551

INDEX 557

O autorze

HEINZ P. BLOCH, MS, is a Consulting Engineer. Previously, Mr. Bloch held the position of regional machinery specialist for the United States at Exxon Chemical. He has authored seventeen books and more than 330 papers and articles and conducted more than 500 technical courses on such issues as practical machinery management, failure analysis and avoidance, turbomachinery, oil mist lubrication, and practical lubrication for industrial facilities.