A Practical Guide to Compressor Technology

by Bloch, Heinz P.

• ISBN13: 9780471727934
• ISBN10: 0471727938
• Edition: 2nd
• Format: Hardcover
• Copyright: 2006-09-14
• Publisher: Wiley-Interscience

Summary

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.

Author Biography

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.

Table of Contents

Preface	p. xiii
Acknowledgments	p. xv
Positive Displacement Compressor Technology	p. 1
Theory	p. 3
Symbols	p. 3
How a Compressor Works	p. 4
First Law of Thermodynamics	p. 8
Second Law of Thermodynamics	p. 8
Ideal or Perfect Gas Laws	p. 9
Boyle's Law	p. 9
Charles' Law	p. 9
Amonton's Law	p. 9
Dalton's Law	p. 9
Amagat's Law	p. 10
Avogadro's Law	p. 10
Perfect Gas Formula	p. 10
Vapor Pressure	p. 11
Gas and Vapor	p. 11
Partial Pressures	p. 11
Critical Conditions	p. 13
Compressibility	p. 13
Generalized Compressibility Charts	p. 14
Gas Mixtures	p. 15
The Mole	p. 15
Specific Volume and Density	p. 16
Volume Percent of Constituents	p. 16
Molecular Weight of a Mixture	p. 16
Specific Gravity and Partial Pressure	p. 17
Ratio of Specific Heats	p. 17
Pseudo-critical Conditions and Compressibility	p. 18
Weight-Basis Items	p. 18
Compression Cycles	p. 19
Power Requirement	p. 20
Compressibility Correction	p. 21
Multiple Staging	p. 22
Volume References	p. 23
Cylinder Clearance and Volumetric Efficiency	p. 24
Cylinder Clearance and Compression Efficiency	p. 27
Reference	p. 27
Reciprocating Process Compressor Design Overview	p. 29
Crankshaft Design	p. 33
Bearings and Lubrication Systems	p. 37
Connecting Rods	p. 37
Crossheads	p. 38
Frames and Cylinders	p. 39
Cooling Provisions	p. 45
Pistons	p. 47
Piston and Rider Rings	p. 47
Valves	p. 48
Piston Rods	p. 51
Packings	p. 55
Cylinder Lubrication	p. 55
Distance Pieces	p. 56
Reciprocating Compressor Modernization	p. 57
Cylinder Upgrades	p. 59
Design for Easy Maintenance	p. 59
Crosshead Designs and Attention to Reliable Lubrication	p. 61
Materials	p. 62
Reciprocating Compressor Performance and Monitoring Considerations	p. 63
Capacity Control	p. 63
Recycle or Bypass	p. 64
Suction Throttling	p. 64
Suction Valve Unloading	p. 65
Clearance Pockets	p. 67
More About Cylinder Jacket Cooling and Heating Arrangements	p. 70
Methods of Cooling	p. 71
Comparing Lubricated and Nonlubricated Conventional Cylinder Construction	p. 73
Lubricated Cylinder Designs	p. 73
Nonlubricated Cylinder Design	p. 75
Compressor Vent and Buffer Systems	p. 76
Compressor Instrumentation	p. 77
Electric vs. Pneumatic Switches	p. 82
Switch Set Points	p. 82
Control Panels	p. 82
Valve-in-Piston Reciprocating Compressors	p. 83
Barrel-Frame Reciprocating Compressors	p. 84
Condition Monitoring of Reciprocating Compressors	p. 85
Maintenance Strategies	p. 86
Justification for Machine Monitoring	p. 86
What to Monitor and Why	p. 87
References	p. 97
Labyrinth Piston Compressors	p. 99
Main Design Features	p. 99
Energy Consumption	p. 101
Sealing Problems	p. 104
Hypercompressors	p. 109
Introduction	p. 109
Cylinders and Piston Seals	p. 111
Cylinder Heads and Valves	p. 115
Drive Mechanism	p. 117
Miscellaneous Problems	p. 119
Conclusions	p. 120
Metal Diaphragm Compressors	p. 121
Introduction	p. 121
Terminology	p. 121
Description	p. 122
Lobe and Sliding Vane Compressors	p. 129
Liquid Ring Compressors	p. 135
Rotary Screw Compressors and Filter Separators	p. 141
Twin-Screw Machines	p. 141
Working Phases	p. 141
Areas of Application	p. 145
Dry vs. Liquid-Injected Machines	p. 145
Operating Principles	p. 145
Flow Calculation	p. 147
Power Calculation	p. 147
Temperature Rise	p. 150
Capacity Control	p. 150
Mechanical Construction	p. 153
Industry Experience	p. 154
Maintenance History	p. 158
Performance Summary	p. 158
Oil-Flooded Single-Screw Compressors	p. 160
Selecting Modern Reverse-Flow Filter-Separator Technology	p. 163
Conventional Filter-Separators vs. SCCs	p. 164
Removal Efficiencies	p. 165
Filter Quality	p. 165
Selecting the Most Suitable Gas Filtration Equipment	p. 166
Evaluating the Proposed Configurations	p. 167
Life-Cycle-Cost Calculations	p. 168
Conclusions	p. 169
Reciprocating Compressor Performance and Sizing Fundamentals	p. 171
Theoretical Maximum Capacity	p. 172
Capacity Losses	p. 173
Valve Preload	p. 174
Valve and Gas Passage Throttling	p. 174
Piston Ring Leakage	p. 176
Packing Leakage	p. 177
Discharge Valve Leakage	p. 177
Suction Valve Leakage	p. 178
Heating Effects	p. 178
Pulsation Effects	p. 180
Horsepower	p. 181
Horsepower Adders	p. 181
Gas Properties	p. 182
Ideal Gas	p. 182
Real Gas	p. 182
Alternative Equations of State	p. 183
Condensation	p. 183
Frame Loads	p. 183
Compressor Displacement and Clearance	p. 184
Staging	p. 186
Fundamentals of Sizing	p. 187
Number of Stages	p. 187
Approximate Horsepower	p. 187
Cylinder Bore Requirements	p. 188
Frame Load	p. 188
Vendor Confirmation	p. 189
Sizing Examples	p. 189
Dynamic Compressor Technology	p. 197
Simplified Equations for Determining the Performance of Dynamic Compressors	p. 205
Nonoverloading Characteristics of Centrifugal Compressors	p. 205
Stability	p. 205
Speed Change	p. 207
Compressor Drive	p. 207
Calculations	p. 208
Design Considerations and Manufacturing Techniques	p. 215
Axially vs. Radially Split	p. 215
Tightness	p. 215
Material Stress	p. 215
Nozzle Location and Maintenance	p. 216
Design Overview	p. 217
Casings	p. 217
Flow Path	p. 230
Rotors	p. 234
Impellers	p. 234
Axial Blading	p. 242
Seals	p. 242
Bearing Configurations	p. 250
Radial Bearings	p. 250
Thrust Bearings	p. 251
Flexure Pivot Tilt Pad Bearings	p. 253
Casing Design Criteria	p. 257
Casing Manufacturing Techniques	p. 265
Stage Design Considerations	p. 273
Impeller Manufacturing Techniques	p. 282
Rotor Dynamic Considerations	p. 286
Fouling Considerations and Coatings	p. 292
Polymerization and Fouling	p. 292
Fouling and Its Effect on Compressor Operation	p. 293
Coating Case Study	p. 294
SermaLon Coating	p. 296
Results	p. 297
Advanced Sealing and Bearing Systems	p. 299
Background	p. 299
Dry Seals	p. 300
Operating Principles	p. 300
Operating Experience	p. 302
Problems and Solutions	p. 303
Dry Seal Upgrade Developments	p. 304
Dry Gas Seal Failures Avoided by Gas Conditioning	p. 304
Magnetic Bearings	p. 308
Operating Principles	p. 308
Operating Experience and Benefits	p. 310
Problems and Solutions	p. 311
Development Efforts	p. 311
Thrust-Reducing Seals	p. 312
Integrated Designs	p. 314
Fluid-Induced Instability and Externally Pressurized Bearings	p. 318
Instability Considerations	p. 318
Fluid-Induced Instability	p. 318
Eccentricity and Stiffness	p. 320
Externally Pressurized Bearings and Seals	p. 321
Practical Applications	p. 324
Rotor Model, Dynamic Stiffness, and Fluid Instability	p. 325
Root Locus Stability Analysis	p. 327
More About Externally Pressurized Bearings	p. 328
Field Data Collection	p. 331
Test Stand Data	p. 334
Conclusions	p. 336
References	p. 336
Suggested Reading	p. 336
Couplings, Torque Transmission, and Torque Sensing	p. 339
Coupling Overview	p. 339
Low Overhung Moment	p. 341
Low Residual Unbalance Desired	p. 343
Long Life and Maintainability	p. 344
Continuous Lubrication Not a Cure-All	p. 345
Contoured Diaphragm Coupling	p. 345
Coupling Retrofits and Upgrades	p. 347
Performance Optimization Through Torque Monitoring	p. 349
Lubrication, Sealing, and Control Oil Systems for Turbomachinery	p. 357
Considerations Common to All Systems	p. 357
Seal Oil Considerations	p. 359
Compressor Control	p. 363
Introduction	p. 363
Control System Objectives	p. 363
Compressor Maps	p. 364
Invariant Coordinates	p. 366
Performance Control	p. 368
PI and PID Control Algorithms	p. 370
Stability Considerations	p. 372
Integral or Reset Windup	p. 373
Performance Limitations	p. 373
Surge Limit	p. 374
Stonewall	p. 375
Preventing Surge	p. 376
Antisurge Control Variables	p. 376
Antisurge Control Algorithms	p. 378
Controlling Limiting Variables	p. 378
Loop Decoupling	p. 379
Conclusions	p. 380
Reference	p. 380
Head-Flow Curve Shape of Centrifugal Compressors	p. 381
Compressor Stage	p. 381
Elements of the Characteristic Shape	p. 382
Basic Slope	p. 382
Blade Angle	p. 384
Fan Law Effect	p. 385
Choke Effect	p. 386
Mach Number	p. 387
Significance of Gas Weight	p. 387
Inducer Impeller Effects on Head Output	p. 388
Surge	p. 389
Vaned Diffusers	p. 390
Vaneless Diffusers	p. 390
Equivalent Tip Speeds	p. 391
Conclusions	p. 393
Use of Multiple-Inlet Compressors	p. 395
Critical Selection Criteria	p. 395
Head Rise to Surge, Surge Margin, and Overload Margin	p. 396
Head per Section	p. 397
Compressor Parasitic Flows	p. 398
Excess Margins on Other Process Equipment	p. 399
Representing Compressor Performance	p. 399
Practical Levels of Critical Operating Parameters	p. 399
Design of a Sideload Compressor	p. 401
Mixing Area	p. 402
Aerodynamics	p. 403
Temperature Stratification	p. 405
Testing	p. 405
Test Setup	p. 406
Instrumentation	p. 406
Testing Procedure	p. 406
Accuracy of Test Results	p. 407
Evaluation of Results	p. 407
Compressor Performance Testing	p. 409
Performance Testing of New Compressors	p. 409
Re-rate Options	p. 410
General Guidelines	p. 410
Gas Sampling	p. 411
Instrumentation	p. 412
Sideload Compressors	p. 414
Calculation Procedures	p. 416
Shop Testing and Types of Tests	p. 418
Field Testing	p. 420
Predicting Compressor Performance at Other Than As-Designed Conditions	p. 432
How Performance Tests Are Documented	p. 434
Design Parameters: What Affects Performance	p. 434
What to Seek from Vendors' Documents	p. 435
Illustrations and Example	p. 436
References	p. 441
Procurement, Audit, and Asset Management Decisions	p. 443
Incentives to Buy from Knowledgeable and Cooperative Compressor Vendors	p. 443
Industry Standards and Their Purpose	p. 444
Typical Scope of Standards	p. 444
Disclaimers in Standards	p. 447
Going Beyond the Standards	p. 447
Disadvantages of Cheap Process Compressors	p. 448
Audits vs. Reviews	p. 449
Staffing and Timing of Audits and Reviews	p. 450
Use of Equipment Downtime Statistics	p. 450
Auditing and Reviewing Compressors	p. 451
Compressor Inspection: Extension of the Audit Effort	p. 465
Inspection of a Welded Impeller (Wheel) and the Entire Rotor	p. 466
Compressor Installation Specifications	p. 474
Field Erection and Installation Specifications for Special-Purpose Machinery	p. 475
References	p. 476
Reliability-Driven Asset Management Strategies	p. 477
Strategy for Reciprocating Compressors	p. 477
Process Operating Window	p. 478
Breakdown Maintenance	p. 478
Time-Based Maintenance	p. 478
Equipment Health Monitoring	p. 479
Reliability and Maintenance	p. 479
Asset Management Strategy	p. 479
Achieving Compressor Asset Optimization	p. 486
Input Obtained from Workshops	p. 486
Conclusions	p. 496
References	p. 497
Properties of Common Gases	p. 499
Shortcut Calculations and Graphical Compressor Selection Procedures	p. 507
Bibliography and List of Contributors	p. 551
Index	p. 557
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