Corrosion and Materials Selection

Preface xxiii

Acknowledgements xxv

1. Fundamentals of Corrosion in the Oil, Gas, and Chemical Industries 1

1.1 Uniform Corrosion 2

1.2 Localized Corrosion 3

1.2.1 Galvanic Corrosion 3

1.2.2 Pitting Corrosion 3

1.2.3 Selective Attack 3

1.2.4 Stray Current Corrosion 4

1.2.5 Microbial Corrosion 4

1.2.6 Intergranular Corrosion 4

1.2.7 Concentration Cell Corrosion (Crevice) 4

1.2.8 Thermogalvanic Corrosion 4

1.2.9 Corrosion Caused By Combined Action 5

1.2.10 Corrosion Fatigue 5

1.2.11 Fretting Corrosion 5

1.2.12 Stress Corrosion Cracking 5

1.2.13 Hydrogen Damage 5

1.3 Low-Temperature Corrosion 6

1.3.1 Low-Temperature Corrosion by Feed-Stock Contaminants 6

1.3.2 Low-Temperature Corrosion by Process Chemicals 8

1.4 High-Temperature Corrosion 12

1.4.1 Sulfidic Corrosion 13

1.4.2 Sulfidic Corrosion without Hydrogen Present 13

1.4.3 Sulfidic Corrosion with Hydrogen Present 13

1.4.4 Naphthenic Acids 14

1.4.5 Fuel Ash 16

1.4.6 Oxidation 16

2. Corrosion Problems in the Petroleum and Chemical Industries 17

2.1 Stress Corrosion Cracking and Embrittlement 17

2.1.1 Chloride Cracking 18

2.1.2 Caustic Cracking 21

2.1.3 Ammonia Cracking 23

2.1.4 Amine Cracking 25

2.1.5 Polythionic Acid Cracking 25

2.1.6 Hydrogen Damage 26

2.2 Hydrogen Attack 30

2.2.1 Forms of Hydrogen Attack 31

2.2.2 Prevention of Hydrogen Attack 32

2.3 Corrosion Fatigue 33

2.3.1 Prevention of Corrosion Fatigue 33

2.4 Liquid-Metal Embrittlement 33

2.4.1 Prevention of Zinc Embrittlement 34

2.5 Basic Definition of Erosion-Corrosion 35

2.5.1 Cavitation 35

2.6 Mixed-Phase Flow 35

2.7 Entrained Catalyst Particles 36

2.8 Systematic Analysis of Project 36

2.8.1 Organization of Work 38

2.8.2 Teamwork 38

2.8.3 Sources of Information 40

2.8.4 Environmental Conditions 41

2.8.5 Case Histories and Technical Data Records 42

2.8.6 Analysis 43

2.9 Forms of Corrosion and Preventive Measures 43

2.9.1 Uniform or General Corrosion 44

2.9.2 Galvanic or Two-Metal Corrosion 45

2.9.3 Crevice Corrosion 46

2.9.4 Pitting 47

2.10 Selective Leaching or De-Alloying Corrosion 49

2.10.1 Dezincification: Characteristics 49

2.10.2 Graphitization 49

2.11 Erosion-Corrosion 50

2.11.1 Surface Films 51

2.11.2 Effect of Velocity 51

2.11.3 Effect of Turbulent Flow 51

2.11.4 Effect of Impingement 52

2.11.5 Galvanic Effect 52

2.11.6 Nature of Metal or Alloy 52

2.11.7 Combating Erosion-Corrosion 52

2.12 Stress Corrosion Cracking 52

2.12.1 Crack Morphology 53

2.12.2 Stress Effects 53

2.12.3 Corrosion Fatigue 53

2.12.4 Methods of Prevention 53

2.13 Types of Hydrogen Damage 54

2.13.1 Causes of Hydrogen Damage 54

2.13.2 Preventive Measures 55

2.14 Concentration Cell Corrosion 55

2.14.1 Metal Ion Concentration Cells 55

2.14.2 Oxygen Concentration Cells 55

2.14.3 Active-Passive Cells 55

2.15 Filiform Corrosion 56

2.16 Types of Intergranular Corrosion 56

2.17 Microbiologically Influenced Corrosion 57

2.18 Corrosion in Concrete 58

3. Corrosion Considerations in Material Selection 61

3.1 Corrosion in Oil and Gas Products 61

3.1.1 Effect of CO2 62

3.1.2 Effect of Temperature 62

3.1.3 Effect of Pressure 62

3.1.4 Prediction of CO2 Corrosion Rate 62

3.1.5 Effect of H2S 68

3.2 Corrosives and Corrosion Problems in Refineries and Petrochemical Plants 74

3.2.1 Sulfur Content 74

3.2.2 Erosion 75

3.2.3 Naphthenic Acid 75

3.2.4 Hydrogen 75

3.2.5 Polythionic Stress Cracking 75

3.2.6 Caustic Embrittlement by Amine Solution 75

3.2.7 Salts 75

3.2.8 Condensate 75

3.2.9 High Temperature 75

3.2.10 CO2 Corrosion 76

3.2.11 Amine Solution 76

3.2.12 H2S 76

3.2.13 H2SO4 76

3.2.14 Hydrogen Fluoride 76

3.2.15 Acetic Acid 76

3.2.16 Ammonia 77

3.2.17 Fuel Ash 77

3.2.18 Micro-organisms 77

3.2.19 Special Material Requirements for Refinery Equipment 77

3.2.20 Special Equipment Requirements for Pressure Vessels (Including Exchanger Shells, Channels, etc.) 78

3.2.21 Storage Tanks 79

3.2.22 Heat Exchanger Tube Bundles 79

3.2.23 Furnaces 80

3.2.24 Piping 80

3.2.25 Low-Temperature Piping 80

3.2.26 Corrosion-Resistant Piping 81

3.2.27 Corrosion-Resistant Valves 81

3.2.28 Flare Systems 82

3.2.29 Rotating Machinery 82

3.2.30 Special Material Requirements in Petrochemical Plants 82

3.2.31 Supplemental Requirements for Equipment in Sour Service 82

3.2.32 Carbon Steel 86

3.2.33 Fabrication Requirements 88

4. Engineering Materials 89

4.1 The Range of Materials 89

4.2 Properties of Engineering Materials 89

4.3 Corrosion Prevention Measures 91

4.3.1 Cathodic Protection 91

4.3.2 Coating, Painting, and Lining Materials 92

4.3.3 Inhibitors 92

4.4 Material Selection Procedure 93

4.5 Guidelines on Material Selection 93

4.6 Procedure for Material Selection 96

4.7 Process Parameters 97

4.8 Corrosion Rate and Corrosion Allowances 97

4.8.1 Calculation 98

4.8.2 Corrosion Study by Literature Survey 98

4.8.3 Corrosion Tests 98

4.9 Corrosion Allowance 100

4.10 Selection of Corrosion-Resistance Alloys 100

4.11 Economics in Material Selection 102

4.11.1 Cost-Effective Selection 102

4.11.2 Economic Evaluation Techniques 102

4.12 Materials Appreciation and Optimization 103

4.13 Corrosion in Oil and Gas Products 104

4.14 Engineering Materials 105

4.14.1 Ferrous Alloys 105

4.14.2 Carbon Steels 105

4.14.3 Surface Hardening 106

4.14.4 Alloy Steels 106

4.15 Cast Iron 112

4.15.1 Malleable Irons 112

4.15.2 Alloy Cast Irons 112

4.16 Non-Ferrous Metals 113

4.16.1 Aluminum 113

4.16.2 Copper 113

4.16.3 Lead and its Alloys 116

4.16.4 Nickel 116

4.16.5 Titanium 116

4.17 Polymers 116

4.17.1 Thermoplastics 116

4.17.2 Elastomers 120

4.17.3 Thermosetting Materials 120

4.18 Ceramics and Glasses 120

4.19 Composite Materials 123

4.19.1 Timber and Plywood 123

4.19.2 Fiber-Reinforced Materials 123

4.19.3 Sandwich Structures 123

5. Chemical Control of Corrosive Environments 125

5.1 General Requirements and Rules for Corrosion Control 125

5.1.1 Corrosion Inhibitors 126

5.1.2 Types of Inhibitor 126

5.2 Basic Types of Inhibitors and How They Work 127

5.2.1 Polarization Diagrams 127

5.2.2 Types of Inhibitor 128

5.3 Corrosive Environments 137

5.3.1 Aqueous Systems 137

5.3.2 Strong Acids 138

5.3.3 Non-Aqueous Systems 138

5.3.4 Gaseous Environments 138

5.3.5 Effect of Elevated Temperatures 138

5.4 Techniques for the Application of Inhibitors 139

5.4.1 Continuous Injection 139

5.4.2 Batch Treatment 139

5.4.3 Squeeze Treatment 139

5.4.4 Volatilization 139

5.4.5 Coatings 140

5.5 Inhibitor Mechanisms 140

5.5.1 Neutralizing Inhibitors 140

5.5.2 Filming Inhibitors 140

5.5.3 Scavengers 140

5.5.4 Miscellaneous Inhibitors 141

5.6 Criteria for Corrosion Control by Inhibitors 141

5.7 System Condition 141

5.8 Selection of Inhibitors 143

5.8.1 Procedure for Selection 143

5.9 Economics of Inhibition 150

5.10 Environmental Factors for Corrosion Inhibitor Applications 151

5.10.1 Aqueous Systems 151

5.10.2 Effects of Various Dissolved Species 151

5.10.3 Gaseous Environments 155

6. Requirements for Corrosion Control in the Petroleum and Petrochemical Industries 159

6.1 Exploration 159

6.1.1 Factors Important in Corrosion Attack During Drilling and Their Control 160

6.1.2 Some Problems Related to Water-Based Fluids and Their Control 161

6.1.3 Techniques to Control Corrosion in Drilling Operations 163

6.2 Production 167

6.2.1 Characteristics of Oil and Gas Wells 167

6.2.2 Oil Wells 167

6.2.3 Gas Wells 168

6.2.4 Offshore Production 169

6.3 System Requirements for Corrosion Control of Oil Fields by Inhibitors 169

6.3.1 Pipelines and Flow Lines 169

6.3.2 Production Systems 169

6.3.3 Other Factors Affecting Corrosion Inhibitor Requirements 171

6.4 Types of Inhibitor 172

6.5 Selection of Inhibitor 173

6.6 Measurement 174

6.7 Factors Governing Oil Well Corrosion 175

6.8 Application of Inhibitor 177

6.8.1 Gas Condensate and Flowing Oil Wells 177

6.8.2 Gas Lift Wells 179

6.8.3 Pumping Wells 179

6.8.4 Gas Pipelines 180

6.9 Water Flooding and Water Disposal 181

6.10 Transportation and Storage 181

6.10.1 Corrosion Control by Inhibitor 181

6.11 Biological Control in Oil and Gas Systems 183

6.11.1 Culture and Identification 183

6.11.2 Scales and Deposits 184

6.11.3 Chemical Control 184

6.12 Scale Control in Oil Systems 185

6.12.1 The Formation of Scale 185

6.12.2 Oilfield Scales 186

6.12.3 Preventing Scale Formation 188

6.12.4 Relative Effectiveness of Scale Control Chemicals 190

6.12.5 Types of Scale Inhibitor 191

6.12.6 Identification of Scale 191

6.12.7 Predicting Scale Formation by Calculation 192

7. Corrosion Inhibitors in Refineries and Petrochemical Plants 205

7.1 Nature of Corrosive Fluids 205

7.1.1 Gas Phase 206

7.1.2 Liquid Hydrocarbon Phase 206

7.1.3 Liquid Aqueous Phase 206

7.2 Corrosion of Steel 206

7.3 Corrosion of Copper Alloys 207

7.4 Neutralizing Corrosion Inhibitors 207

7.5 Filming Inhibitors 208

7.6 Special Concepts in the Use of Corrosion Inhibitors in Refineries 209

7.6.1 Temperature Limitations 209

7.6.2 Insufficient Concentration 209

7.6.3 Surfactant Properties of Inhibitors 209

7.7 Economic Aspects of Chemical Inhibition and Other Measures for Corrosion Prevention 210

7.7.1 Altering the Metal 210

7.7.2 Corrosion Prevention Barriers 210

7.7.3 Altering the Corrosive Environment 211

7.8 Special Refinery Processes Amenable to Corrosion Inhibitors 211

7.8.1 Hydrogen Blistering Problems 211

7.9 Corrosion in Gas Processing Units 212

7.10 Miscellaneous Refinery Corrosion Problems 213

7.11 Selection of Inhibitor 214

7.11.1 Test Methods 214

7.12 Control of Fouling 214

7.12.1 Inorganic Fouling Deposits 215

7.12.2 Organic Fouling Deposits 215

7.12.3 Use of Anti-Foulants 216

7.12.4 Evaluation of Anti-Foulants 216

7.13 Utility (Cooling Water and Boiler Systems) 218

7.13.1 Corrosion Control in Cooling Water Systems 218

7.13.2 Corrosion Control in Boiler Systems 220

7.14 Boiler Corrosion Problems 221

7.14.1 Deposits in Boilers 221

7.14.2 Problems from Carryover 221

7.14.3 Corrosion Problems 223

7.14.4 High-temperature hot water systems 234

7.15 Treatment of Acid Systems 235

7.15.1 Industrial Exposures of Metals to Acids 235

7.15.2 Cleaning of Oil Refinery Equipment 235

7.15.3 Heat Exchangers 236

7.15.4 Oil-Well Acidizing 236

7.15.5 Manufacturing Processes 236

7.15.6 Vapor-Liquid Systems: Condensing Vapors 237

7.16 Chemical Cleaning of Process Equipment 237

7.16.1 Fouling of Equipment 237

7.17 Critical Equipment Areas 239

7.17.1 Columns 239

7.17.2 Glass-Lined Vessels 239

7.17.3 Oxygen, Chlorine, and Fluorine Piping Systems 239

7.18 Identification of Deposits 239

7.18.1 Preoperational Cleaning 241

7.18.2 Boilers 241

7.18.3 Columns 241

7.18.4 Shell and Tube Heat Exchangers 241

7.18.5 Cleaning of Boilers 241

7.18.6 Cleaning of Furnaces 242

7.18.7 Cleaning of Pumps and Compressors 242

7.18.8 Cleaning of Piping 242

7.19 Chemical Cleaning 242

7.19.1 Chemical Cleaning Methods 243

7.19.2 Chemical Cleaning Solutions 244

8. Corrosion Inhibitor Evaluations 247

8.1 On-Line Monitoring of Corrosion 247

8.2 Corrosion Monitoring Techniques 248

8.3 Selecting a Technique for Corrosion Monitoring 248

8.3.1 Where the Primary Objective is Diagnosis in a New Situation 248

8.3.2 Where the Primary Objective is to Monitor the Behavior of a Known System 251

8.3.3 Criteria for Selection of Technique 251

8.4 Corrosion Monitoring Strategy 254

8.4.1 Equipment 255

8.4.2 Weight Loss Coupons 255

8.4.3 Spool Pieces 256

8.4.4 Field Signature Method (Electric Fingerprint) 256

8.4.5 Electrical Resistance Probes 257

8.4.6 Electrochemical Probes 258

8.4.7 Electrochemical Noise 258

8.4.8 Solid Particle Impingement Probes 259

8.4.9 Hydrogen Probes and Patch Monitors 259

8.4.10 Galvanic Probes 260

8.4.11 Electrical Potential Monitoring 260

8.4.12 pH Probes 261

8.4.13 Measurement of Dissolved Gases 262

8.4.14 Pipeline Inspection Tools 263

8.4.15 Ultrasonic Thickness Measurement 264

8.4.16 Radiography 264

8.4.17 Side Stream Monitoring 265

8.4.18 Visual Inspection 265

8.4.19 Failure Analysis 265

8.4.20 Bacterial Methods 265

8.5 Measurement of Dissolved Solids 267

8.6 Measurement of Suspended Solids 267

8.7 Corrosion Product Analysis 267

8.8 Design Requirements 268

8.8.1 Access Fitting Location 268

8.8.2 Access Fitting Design 268

8.8.3 Materials Selection 269

8.9 Automated Systems 270

8.9.1 Manual Methods 270

8.9.2 Data Loggers/Collection Units 270

8.9.3 Transmitter Units 270

8.9.4 Computers 270

8.9.5 Data Analysis and Reporting 271

8.9.6 Guidelines for Safe On-Line Installation and Retrieval of Corrosion Monitoring Devices 271

8.10 Evaluation of Corrosion Inhibitors 273

8.10.1 Reasons for Inhibitor Testing 273

8.10.2 Inhibitor Properties 274

8.10.3 Test Conditions 274

8.11 Detection of Corrosion 275

8.11.1 Methods Involving Loss of metal 275

8.11.2 Indirect Measurements for Corrosion Detection 276

8.11.3 Utilization of Film Measurements 277

8.12 Miscellaneous Corrosion Tests 278

8.13 Results of the Test Method 278

8.14 Field Testing of Inhibitors 279

8.14.1 Illustrations of Complex Testing Procedures Necessary to Simulate Field Conditions 279

8.15 Inhibitor Properties Other Than Effectiveness in Mitigating Corrosion 283

8.15.1 Influence of Density 284

8.15.2 Influence of Solubility 284

8.15.3 Surface-Active Characteristics 285

8.15.4 Testing for Solubility, Dispersibility, Emulsion, and Foaming 285

8.15.5 Formation of Sludges or Precipitates 285

8.15.6 Ecological Effects 286

8.15.7 Effects of Temperature 286

8.16 Monitoring of Corrosion Inhibitors 286

8.16.1 Water Samples 286

8.16.2 Corrosion Coupons 287

8.16.3 Inhibitor Residuals 287

8.16.4 Electric Resistance Probes and Corrosion Monitoring Probes 287

8.17 Corrosion Behavior of High-Alloy Tubular Materials in Inhibited Acidizing Conditions 288

8.17.1 Experimental Procedure 288

8.17.2 Weight Loss 292

8.17.3 Low-Alloy Steel 292

8.17.4 Crevice Corrosion 292

8.17.5 Conclusions and Recommendations 292

9. Compatibility in Material Selection 295

9.1 Requirements for Compatibility 296

9.2 Structures and Equipment 300

9.3 Piping Systems 302

9.4 Fasteners 304

9.5 Encapsulation, Sealing, and Enveloping 306

9.6 Electrical and Electronic Equipment 306

9.6.1 Grounding and Bonding of Electrical Equipment 307

9.7 Coatings, Films, and Treatments 308

9.8 Chemical Compatibility 310

9.9 Environment 311

9.10 Stray Currents 311

9.11 Beneficial Results 313

9.12 Shape or Geometry 313

9.12.1 Requirements 314

9.13 Structures 315

9.13.1 Piping Systems 317

9.13.2 Tanks and Vessels 321

9.14 Mechanics 322

9.14.1 Requirements 323

9.14.2 Structures 327

9.14.3 Equipment 329

9.14.4 Piping Systems 331

9.14.5 Vibration Transfer 332

9.14.6 Surface Treatment (from a Mechanical Point of View) 333

9.14.7 Electrical and Electronic Equipment (from a Mechanical Point of View) 334

10. Surface Preparation, Protection and Maintenance 337

10.1 Surface 337

10.1.1 Requirements 337

10.1.2 Structures 342

10.1.3 Equipment 345

10.1.4 Piping Systems (from a Surface Point of View) 346

10.1.5 Surface Preparation 347

10.1.6 Electrical and Electronic Equipment 350

10.2 Protection 350

10.2.1 Requirements 352

10.2.2 Protection by Separation of Materials from the Environment 352

10.2.3 Electrochemical Cathodic and Anodic Protection 360

10.2.4 Protection by Adjustment of Environment 362

10.2.5 Protection of Structures 363

10.2.6 Protection of Equipment 367

10.2.7 Protection of Pipe Systems 368

10.2.8 Protection of Electrical and Electronic Equipment 370

10.3 Maintenance 373

10.3.1 Requirements 374

10.3.2 Structures and Equipment 375

10.4 Economics 376

10.4.1 Requirements 377

10.4.2 Methods of Appraisal 380

10.4.3 Economics Applied to Structures 381

10.4.4 Economics Applied to Equipment and Pipe Systems 382

11. Fabrication and Choice of Material to Minimize Corrosion Damage 385

11.1 Design 385

11.2 Materials 387

11.2.1 Specific Material Considerations: Metals 388

11.2.2 Material Considerations: Non-metals 389

11.3 Fabrication 389

11.3.1 Welding 390

11.4 Welding Procedure 408

11.4.1 Welding of Stainless Steels 408

11.4.2 Cleaning Procedures 409

11.4.3 Weld Design and Procedure 409

11.4.4 Weld Defects 409

11.4.5 Carbon and Low-Alloy Steels 409

11.4.6 Stainless steels 411

11.4.7 Nickel Alloys 412

11.4.8 Aluminum Alloys 412

11.4.9 Other Materials for Welding 413

11.5 Welding and Joining 413

11.5.1 Mechanical Fasteners 414

11.5.2 Joining, Brazing, and Soldering 414

11.5.3 Protection of welded joints 414

11.5.4 Pressure Pipe Brazing and Soldering 415

11.6 Soldered Joints 416

11.7 Brazed Joints 417

11.8 Pipe Bending and Forming 418

11.8.1 Bending 418

11.8.2 Forming 421

12. Heat Treatment 423

12.1 General Heat Treatment Requirements 423

12.1.1 Governing Thickness 424

12.1.2 Heating and Cooling 424

12.1.3 Temperature Verification 425

12.1.4 Hardness Tests 425

12.1.5 Specific Requirements of Heat Treatment 425

12.1.6 Alternative Heat Treatment 426

12.1.7 Exceptions to Basic Requirements 426

12.1.8 Dissimilar Materials 426

12.1.9 Delayed Heat Treatment 426

12.1.10 Partial Heat Treatment 426

12.1.11 Local Heat Treatment 426

12.1.12 Heat Treatment of Casing and Tubing 427

12.2 Heat Treatment Process 427

12.2.1 Heat Treatment of Stainless Steel 428

12.3 Preheating of Metals 429

12.3.1 Requirements and Recommendations 430

12.3.2 Heat Treatment Specific Requirements 430

12.4 Surface Treatment of Stainless Steel 432

12.4.1 Surface Condition 432

12.4.2 Passivation Techniques 432

12.4.3 Cleaning 432

12.4.4 Passivating 433

12.4.5 Testing 433

12.5 Handling, Transport, Storage, and Erection of Coated Metalwork 434

12.5.1 Selection of Coating Systems 434

12.5.2 Methods of Preventing Damage 434

12.5.3 Storage of Coated Steelwork 434

12.5.4 Responsibilities for Preventing Damage 435

12.5.5 Transportation, Handling, and Storage of Coated Pipes 435

12.5.6 Handling and Storage of Aluminium 436

12.6 Inspection 437

12.6.1 Importance of Inspection 437

12.6.2 Results of a Lack of Good Inspection 437

12.7 Corrosion of Carbon Steel Weldments 438

12.7.1 SCC in Oil Refineries 438

12.7.2 Leaking Carbon Steel Weldments in a Sulfur Recovery Unit 438

12.7.3 Corrosion of Welds in Carbon Steel Deaerator Tanks 440

12.7.4 Weld Cracking in Oil-Refinery Deaerator Vessels 440

Discussion 442

Conclusions 443

12.8 Corrosion of Austenitic Stainless Steel Weldments 444

12.8.1 Effects of GTA Weld Shielding Gas Composition 444

12.8.2 Effects of Heat-Tint Oxides on the Corrosion Resistance Of Austenitic Stainless Steels 444

12.8.3 Unmixed Zones 446

12.8.4 Chloride SCC 446

12.8.5 Caustic Embrittlement (Caustic SCC) 447

12.8.6 Microbiologically Induced Corrosion (MIC) 448

12.9 Corrosion of Ferritic Stainless Steel Weldments 448

12.9.1 Leaking Welds in a Ferritic Stainless Steel Wastewater Vaporizer 448

12.10 Corrosion of Duplex Stainless Steel Weldments 451

12.10.1 Intergranular Corrosion 451

12.10.2 Pitting Tests 451

12.11 Stress-Corrosion Cracking 456

12.12 Use of High-Alloy Filler Metals 456

12.13 Corrosion of Nickel-Bases Alloys 456

12.13.1 The Nickel-Molybdenum Alloys 456

12.13.2 The Nickel-Chromium-Molybdenum Alloys 457

Glossary of Terms 461

Bibliography 523

Index 535