Handbook of cathodic corrosion protection: theory and practice of electrochemical protection processes

Walter von Baeckmann, Wilhelm Schwenk, Werner Prinz9780884150565, 0-88415-056-9

This English translation of the third, revised edition of this textbook, published in 1989 by VCH Verlagsgesellschaft mbH, Weinheim, Germany, contains 24 contributions addressing both theoretical and practical aspects of cathodic protection. It updates economic considerations in light of more stringent regulations and standards and examines the latest developments in electrochemical protection technology. New to this edition are strategies for measuring potential and data evaluation by computer. New chapters address the problem of high voltage and the cathodic protection of steel reinforcement in concrete. Annotation c. by Book News, Inc., Portland, Or.

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Table of contents :
Contents……Page 6
Foreword to the Third Edition……Page 20
Foreword to the First Edition……Page 21
Preface……Page 23
Acknowledgments……Page 24
Index of Authors……Page 25
Commonly Used Quantities, Constants, and Symbols……Page 26
General Symbols……Page 31
American and European Electrical Cable Sizes……Page 33
1.1 Corrosion Protection for Buried Pipelines……Page 34
1.2 Corrosion Protection by Painting……Page 41
1.3 History of Cathodic Protection……Page 42
1.4 Development of Stray Current Protection……Page 53
1.5 Corrosion Protection by Information……Page 56
1.6 References……Page 58
2.1 Corrosion Processes, Corrosion Damage, and Protective Countermeasures……Page 60
2.2 Electrochemical Corrosion……Page 62
2.2.1 Metallic Materials……Page 63
2.2.2 Aqueous Electrolytes……Page 67
2.2.3 Electrochemical Phase Boundary Reactions……Page 69
2.2.4 Mixed Electrodes……Page 77
2.2.5 Observations of Current Distribution……Page 83
2.3 Potential Dependence of Corrosion Extent……Page 85
2.3.1 Almost Uniform Weight Loss Corrosion……Page 86
2.3.2 Pitting Corrosion……Page 95
2.3.3 Stress Corrosion……Page 96
2.3.4 Hydrogen-Induced Corrosion……Page 99
2.3.6 Limits of Applicability of Electrochemical Protection Processes……Page 103
2.4 Critical Protection Potentials and Ranges……Page 104
2.5 References……Page 109
3.1 The Electrical Parameters: Current, Voltage, and Resistance……Page 112
3.2 Reference Electrodes……Page 118
3.3.1 Bases of Potential Measurement of Electrodes with Flowing Current……Page 121
3.3.2 Application of Potential Measurement……Page 129
3.3.3 Application of Protection Criteria……Page 136
3.4.1 General Advice for Measurement of Current……Page 140
3.4.2 Pipe Current Measurement……Page 141
3.4.3 Measurement of Current Density and Coating Resistance……Page 143
3.5 Resistivity Measurement……Page 145
3.5.1 Resistivity Measuring Instruments……Page 146
3.5.2 Measurement of Specific Soil Resistivity……Page 147
3.5.3 Measurement of Grounding Resistance……Page 151
3.6 Location of Faults……Page 152
3.6.1 Measurement of Foreign Contacts……Page 153
3.6.2 Location of Heterogeneous Surface Areas by Measurements of Field Strength……Page 156
3.7 Intensive Measurement Technique……Page 164
3.7.1 Quantities to be Measured and Objectives of Intensive Measurement Technique……Page 165
3.7.2 Carrying Out an Intensive Measurement……Page 168
3.8 References……Page 170
4.1 Action of Corrosion Products and Types of Corrosion……Page 172
4.2 Determining the Corrosion Likelihood of Uncoated Metals……Page 175
4.2.1 Corrosion in Soils……Page 177
4.3 Enhancement of Anodic Corrosion by Cell Formation or Stray Currents from dc Installations……Page 181
4.4 Corrosion Due to ac Interference……Page 183
4.5 References……Page 185
5.1.1 Organic Coatings……Page 186
5.1.4 Metallic Coatings……Page 187
5.2.1 Electrical and Electrochemical Properties……Page 188
5.2.2 Physicochemical Properties……Page 202
5.2.3 Mechanical Properties……Page 203
5.2.4 Corrosion of the Steel under the Coating……Page 204
5.3.1 Corrosion of Mortar……Page 206
5.3.2 Corrosion of Steel in Mortar……Page 207
5.4 Properties of Enamel Coatings……Page 208
5.5 Properties of Metallic Coatings……Page 209
5.6 References……Page 210
6.1 General Information……Page 212
6.1.1 Current Capacity of Galvanic Anodes……Page 213
6.1.2 Current Discharge from Galvanic Anodes……Page 216
6.2.2 Zinc……Page 218
6.2.3 Aluminum……Page 221
6.2.4 Magnesium……Page 224
6.3 Backfill Materials……Page 229
6.4 Supports……Page 231
6.5 Forms of Anodes……Page 232
6.5.2 Plates and Compact Anodes……Page 233
6.5.3 Anodes for Tanks……Page 234
6.5.5 Special Forms……Page 235
6.6 Quality Control and Performance Testing……Page 236
6.7 Advantages and Disadvantages of Galvanic Anodes……Page 237
6.8 References……Page 239
7.1 General Comments……Page 240
7.2.1 Solid Anodes……Page 241
7.2.2 Noble Metals and Valve Metals Coated with Noble Metals……Page 246
7.2.3 Metal Oxide-Coated Valve Metals……Page 249
7.3 Insulating Materials……Page 250
7.4 Cables……Page 251
7.5.1 Anodes Suitable for Soil……Page 252
7.5.2 Anodes Suitable for Water……Page 254
7.5.3 Anodes for Internal Application……Page 255
7.6 References……Page 257
8 Impressed Current Equipment and Transformer- Rectifiers……Page 258
8.1 Site and Electrical Protection Measures……Page 259
8.2 Design and Circuitry of Impressed Current……Page 261
8.3 Rectifier Circuit……Page 262
8.4 Adjustable Transformer-Rectifiers……Page 263
8.5 Rectifiers Resistant to High Voltage……Page 265
8.6 Control Rectifiers……Page 266
8.8 Equipment and Control of Transformer-Rectifiers……Page 270
8.9 References……Page 275
9 Impressed Current Ground Beds and Interference Problems……Page 276
9.1.1 Continuous Horizontal Anode Beds……Page 277
9.1.2 Single Anode Installations……Page 281
9.1.3 Deep Anode Beds……Page 283
9.1.4 Design of Anodes……Page 287
9.2 Interference with Foreign Pipelines and Cables……Page 289
9.2.1 Interference from the Voltage Cone of Anodes……Page 290
9.2.2 Interference from the Cathodic Voltage Cone of the Protected Object……Page 292
9.2.3 Avoidance of Interference……Page 294
9.3 References……Page 297
10.1 Electrical Properties of Steel Pipelines……Page 298
10.2.2 Measures for Achieving a Low Leakage Load……Page 301
10.3.2 Test Points……Page 309
10.3.3 Determination of Current Demand……Page 310
10.3.4 Choice of Protection Method……Page 311
10.3.5 Pipelines for Electrolytically Conducting Liquids……Page 313
10.3.6 Distribution Networks……Page 316
10.4 Commissioning the Cathodic Protection Station……Page 318
10.5 Monitoring and Supervision……Page 320
10.6 References……Page 322
11.2 Preparatory Measures……Page 323
11.3.1 Determination of Current Demand, Evaluation, and Connections of the Protection Equipment……Page 325
11.3.2 Choice of Protection Method……Page 328
11.3.3 Examples of the Design of Protective Installations……Page 329
11.4 Tank Farms and Filling Stations……Page 332
11.5.1 General Comments……Page 333
11.5.2 Equipotential Bonding and Insulating Joints……Page 334
11.5.4 Lightning Protection……Page 335
11.5.5 Interference and Working in the Area of Railways……Page 336
11.7 Internal Protection of Fuel Tanks……Page 337
11.8 Consideration of Other Protection Measures……Page 339
11.9 Operation and Maintenance of Cathodic Protection Stations……Page 340
11.10 References……Page 341
12.1 Range of Applications……Page 342
12.2 Special Features of the Local Cathodic Protection……Page 343
12.3 Power Stations……Page 345
12.4 Oil Refineries……Page 348
12.5 Installations with Small Steel-Reinforced Concrete Foundations……Page 350
12.6 Tank Farms……Page 351
12.7 References……Page 355
13.1 Laying Cables……Page 356
13.2 Passive Corrosion Protection……Page 357
13.3 Cathodic Protection……Page 359
13.3.1 Stray Current Protection……Page 360
13.3.2 Cathodic Protection with Impressed Current Anodes……Page 362
13.4 References……Page 367
14.1 Properties of Buried Power Cables……Page 368
14.2 Cathodic Protection of the Steel Conduits for Power Cables……Page 369
14.2.1 Requirements for dc Decoupling Devices (between Casing and Ground)……Page 370
14.2.2 Types and Circuits of dc Decoupling Devices……Page 371
14.2.4 Control and Maintenance of Cathodic Protection……Page 376
14.3 Stray Current Protection……Page 377
14.4 References……Page 379
15.1.1 dc Equipment……Page 380
15.2.1 Regulations for dc Railways……Page 381
15.2.2 Tunnels for dc Railways……Page 385
15.3 Stray Currents from High-Voltage dc Power Lines……Page 386
15.4 Stray Currents Due to Telluric Currents……Page 388
15.5.1 Stray Current Protection for Individual Pipelines……Page 391
15.5.2 Combined Stray Current Protective Measures in Urban Areas……Page 395
15.6 Stray Current Protection in Harbor Areas……Page 397
15.7 References……Page 399
16.1 Cathodic Protection Measures……Page 400
16.1.1 Design Criteria……Page 401
16.1.2 Protection with Galvanic Anodes……Page 405
16.2.1 Steel Structures……Page 406
16.3 Harbor Structures……Page 409
16.3.1 Impressed Current Equipment……Page 410
16.3.2 Protection with Galvanic Anodes……Page 412
16.5 Piling Foundations……Page 413
16.6 Offshore Pipelines……Page 416
16.7.1 Production Platforms……Page 418
16.7.2 Harbor Structures……Page 420
16.7.3 Offshore Pipelines……Page 421
16.8 References……Page 423
17.1.1 Dissolved Salts and Solid Particles……Page 424
17.1.2 Aeration and Oxygen Content……Page 426
17.1.4 Variations in Temperature and Concentration……Page 427
17.2 Effect of Materials and Coating Parameters……Page 428
17.3 Cathodic Protection Below the Waterline……Page 430
17.3.1 Calculations of the Protection Current Requirement……Page 431
17.3.2 Protection by Galvanic Anodes……Page 432
17.3.3 Protection with Impressed Current……Page 436
17.4 Internal Cathodic Protection of Tanks and Containers……Page 443
17.6 Cathodic Protection of Bilges……Page 445
17.7 Cathodic Protection of Docks……Page 446
17.8 References……Page 447
18.2.1 Formation of Corrosion Cells……Page 448
18.2.4 Corrosion by Anodic Interference (Cell Formation, Stray Currents)……Page 450
18.3.1 Investigations for Corrosion Damage……Page 451
18.3.2 Measurement of ΔU Profiles……Page 0
18.3.3 Measurement of the Tafel Potential……Page 454
18.4 Design and Construction of Cathodic Protection Stations……Page 455
18.5 Commissioning, Maintenance and Control……Page 458
18.6 References……Page 459
19.1 The Corrosion System Steel-Concrete……Page 460
19.3 Electrolytic Properties of Concrete……Page 461
19.4 Criteria for Cathodic Protection……Page 462
19.5.1 Design and Installation……Page 464
19.5.2 Determination of the State of Corrosion of the Reinforcing Steel……Page 465
19.5.3 Reinforcement Continuity……Page 466
19.5.4 Installation and Types of Anode System……Page 467
19.5.5 Concrete Replacement Systems for Cathodic Protection……Page 468
19.5.6 Commissioning, Maintenance and Control……Page 469
19.6 Stray Current Effects and Protective Measures……Page 471
19.7 References……Page 472
20.1 Description and Function of Objects to be Protected……Page 474
20.1.1 Materials for Objects to be Protected and Installation Components……Page 475
20.1.3 Preconditions for Internal Cathodic Protection……Page 476
20.1.4 Measures to Prevent Anodic Interference……Page 477
20.1.5 Measures to Prevent Danger from Hydrogen Evolution……Page 479
20.2 Protection with Galvanic Anodes……Page 480
20.3.1 Equipment with Potential Control……Page 481
20.4.1 Boilers with Enamel Linings……Page 483
20.4.2 Boilers with Electrolytically Treated Water……Page 489
20.4.3 Water Storage Tanks……Page 491
20.4.4 Filter Tanks……Page 494
20.5 Requirements for Drinking Water……Page 495
20.6 References……Page 496
21.1 Special Features of Internal Protection……Page 497
21.2 Cathodic Protection with Galvanic Anodes……Page 499
21.3.1 Internal Cathodic Protection of Wet Oil Tanks……Page 500
21.3.2 Internal Cathodic Protection of a Wet Gasometer……Page 501
21.3.4 Internal Cathodic Protection of a Water Turbine……Page 502
21.4.1 Special Features of Anodic Protection……Page 507
21.4.2 Anodic Protection with Impressed Current……Page 509
21.4.3 Protective Effect of Local Cathodes due to Alloying……Page 516
21.4.4 Protective Action of Inhibitors……Page 517
21.5 Trends in the Application of Internal Electrochemical Protection……Page 518
21.6 References……Page 520
22.1.1 Statistics of Pipeline Failures……Page 522
22.1.2 Measures for Control and Maintenance……Page 523
22.2 General Comments on Economics……Page 524
22.3 Costs of Cathodic Protection of Buried Pipelines……Page 525
22.3.1 Galvanic Anodes……Page 526
22.3.2 Impressed Current Anodes……Page 528
22.3.3 Prolonging the Life of Pipelines……Page 529
22.4 Corrosion Protection of Well Casings……Page 532
22.5 Corrosion Protection in Seawater……Page 533
22.6.1 Internal Cathodic Protection……Page 534
22.6.2 Internal Anodic Protection……Page 535
22.7 References……Page 537
23 Interference Effects of High-Voltage Transmission Lines on Pipelines……Page 538
23.1 Capacitive Interference……Page 539
23.2.1 Contact with a Conductor under High Voltage……Page 540
23.2.2 Voltage Cone of a Pylon Grounding Electrode……Page 541
23.3.1 Causes and Factors Involved……Page 543
23.3.2 Calculation of Pipeline Potentials in the Case of Parallel Routing of a High-Voltage Transmission Line and a Pipeline……Page 544
23.3.3 Obliquely Routed Sections of the Lines……Page 549
23.3.4 Simplified Calculation Methods……Page 550
23.3.5 Representation of the Characteristics of a Pipeline……Page 554
23.4 Limiting Lengths and Limiting Distances……Page 557
23.4.1 Allowable Contact Voltages……Page 558
23.5.2 Long-Term Interference……Page 559
23.5.3 Protective Measures by Grounding……Page 560
23.5.4 Grounding Electrodes and Cathodic Protection……Page 561
23.6 Measurement of Pipeline Potentials……Page 563
23.6.1 Measurement of Short-Term Interference……Page 564
23.6.2 Measurement of Long-Term Interference……Page 565
23.6.3 Results of Pipeline Potential Measurement……Page 566
23.7 References……Page 567
24 Distribution of Current and Potential in a Stationary Electric Field……Page 568
24.1 Grounding Resistance of Anodes and Grounds……Page 569
24.2 Interference Factor with Several Anodes……Page 577
24.3.1 Soil Resistance Formulas……Page 578
24.3.2 Anodic Voltage Cone……Page 579
24.3.3 Cathodic Voltage Cone in a Cylindrical Field……Page 580
24.3.4 Interference from the Cathodic Voltage Cone……Page 581
24.4.1 General Relationships for a Two-Conductor Model……Page 582
24.4.2 Calculation of Ground Electrodes Having a Longitudinal Resistance……Page 583
24.4.3 Range of Cathodic Protection and Current Requirement……Page 585
24.4.4 Potential Distribution in the Case of Overprotection……Page 588
24.4.5 Cathodic Protection in Narrow Gaps……Page 589
24.4.6 Distribution of Current and Potential Inside a Pipe at Insulating Units……Page 590
24.5 General Comments on Current Distribution……Page 591
24.6 References……Page 593
C……Page 594
E……Page 595
I……Page 596
O……Page 597
P……Page 598
S……Page 599
W……Page 600