Rules of Thumb for Chemical Engineers (eBook)

Front cover 1
Title page 4
Copyright page 5
Table of contents 8
SECTION ONE: Equipment Design 14
1. Fluid Flow 15
Velocity Head 16
Full Plant Piping 17
Partially Full Horizontal Pipes 18
Equivalent Length 19
Recommended Velocities 20
Two-phase Flow 22
Compressible Flow—Short (Plant) Lines 25
Compressible Flow—Long Pipelines 31
Sonic Velocity 34
Metering 34
Control Valves 35
Safety Relief Valves 38
2. Heat Exchangers 42
TEMA 43
Selection Guides 47
Pressure Drop Shell and Tube 50
Temperature Difference 52
Shell Diameter 53
Shellside Velocity Maximum 53
Nozzle Velocity Maximum 54
Heat Transfer Coefficients 54
Fouling Resistances 61
Metal Resistances 63
Vacuum Condensers 65
Air-cooled Heat Exchangers: Forced vs Induced Draft 65
Air-cooled Heat Exchangers: Pressure Drop Air Side 66
Air-cooled Heat Exchangers: Rough Rating 67
Air-cooled Heat Exchangers: Temperature Control 69
Miscellaneous Rules of Thumb 71
3. Fractionators 72
Introduction 73
Relative Volatility 73
Minimum Reflux 74
Minimum Stages 75
Actual Reflux and Actual Theoretical Stages 75
Reflux-to-Feed Ratio 76
Actual Trays 77
Graphical Methods 77
Tray Efficiency 80
Diameter of Bubble Cap Trays 84
Diameter of Sieve/Valve Trays (F Factor) 85
Diameter of Sieve/Valve Trays (Smith) 86
Diameter of Sieve/Valve Trays (Lieberman) 88
Diameter of Ballast Trays 88
Diameter of Fractionators, General 90
Control Schemes 90
Optimization Techniques 94
Reboilers 97
Packed Columns 101
4. Absorbers 122
Introduction 123
Hydrocarbon Absorber Design 123
Hydrocarbon Absorbers, Optimization 125
Inorganic Type 126
5. Pumps 129
Affinity Laws 130
Horsepower 130
Efficiency 130
Minimum Flow 130
General Suction System 131
Suction System NPSH Available 132
Suction System NPSH for Studies 133
Suction System NPSH with Dissolved Gas 134
Larger Impeller 134
Construction Materials 134
6. Compressors 137
Ranges of Application 138
Generalized Z 138
Generalized K 139
Horsepower Calculation 140
Efficiency 144
Temperature Rise 146
Surge Controls 146
7. Drivers 147
Motors: Efficiency 148
Motors: Starter Sizes 149
Motors: Service Factor 149
Motors: Useful Equations 150
Motors: Relative Costs 150
Motors: Overloading 151
Steam Turbines: Steam Rate 151
Steam Turbines: Efficiency 151
Gas Turbines: Fuel Rates 152
Gas Engines: Fuel Rates 154
Gas Expanders: Available Energy 154
8. Separators/Accumulators 155
Liquid Residence Time 156
Vapor Residence Time 157
Vapor/Liquid Calculation Method 158
Estimating Equilibria 161
Liquid/Liquid Calculation Method 163
Pressure Drop 163
Vessel Thickness 164
Gas Scrubbers 164
Reflux Drums 164
General Vessel Design Tips 165
9. Boilers 166
Power Plants 167
Controls 167
Thermal Efficiency 168
Stack Gas Enthalpy 169
Stack Gas Quantity 170
Steam Drum Stability 171
Deaerator Venting 172
Water Alkalinity 173
Blowdown Control 173
Impurities in Water 173
Conductivity Versus Dissolved Solids 175
Silica in Steam 176
Caustic Embrittlement 176
Waste Heat 178
10. Cooling Towers 181
System Balances 182
Temperature Data 182
Performance 184
Performance Estimate: A Case History 186
Transfer Units 186
SECTION TWO: Process Design 188
11. Refrigeration 189
Types of Systems 190
Estimating Horsepower per Ton 190
Horsepower and Condenser Duty for Specific Refrigerants 191
Refrigerant Replacements 209
Ethylene/Propylene Cascaded System 210
Steam Jet Type Utilities Requirements 210
Ammonia Absorption Type Utilities Requirements 213
12. Gasification 214
What Is Gasification? 215
Gasification Theory 215
Feedstocks for Gasification 217
Features of Gasification Systems 218
Commercial Gasification Systems 220
Trace Components in Gasifier Syngas 223
13. Gas Treating 226
Introduction 227
Gas Treating Processes 227
Chemical Solvent Processes 229
Physical Solvent Processes 231
Physical/Chemical Solvent Processes 231
Biological Processes 232
Solid Bed Scavengers 232
Membranes 233
14. Vacuum Systems 234
Vacuum Jets 235
Typical Jet Systems 236
Steam Supply 237
Measuring Air Leakage 238
Time to Evacuate 238
Design Recommendations 239
Ejector Specification Sheet 240
15. Pneumatic Conveying 242
Types of Systems 243
Differential Pressures 244
Equipment Sizing 244
16. Blending 246
Single-Stage Mixers 247
Multistage Mixers 247
Gas/Liquid Contacting 248
Liquid/Liquid Mixing 248
Liquid/Solid Mixing 248
Mixer Applications 249
Shrouded Blending Nozzle 250
Vapor Formation Rate for Tank Filling 250
SECTION THREE: Plant Design 252
17. Process Evaluation 253
Introduction 254
Study Definition 254
Process Definition 256
Battery Limits Specifications 263
Offsite Specifications 267
Capital Investments 271
Operating Costs 278
Economics 281
Financing 285
18. Reliability 287
19. Metallurgy 290
Embrittlement 291
Stress-Corrosion Cracking 297
Hydrogen Attack 298
Pitting Corrosion 300
Creep and Creep-Rupture Life 301
Metal dusting 303
Naphthenic Acid Corrosion 305
Fuel Ash Corrosion 306
Thermal Fatigue 308
Abrasive Wear 310
Pipeline Toughness 311
Common Corrosion Mistakes 312
20. Safety 313
Estimating LEL and Flash 314
Tank Blanketing 314
Equipment Purging 316
Static Charge from Fluid Flow 317
Mixture Flammability 320
Relief Manifolds 323
Natural Ventilation 329
21. Controls 330
Introduction 331
Extra Capacity for Process Control 331
Controller Limitations 332
False Economy 333
Definitions of Control Modes 333
Control Mode Comparisons 333
Control Mode vs Application 333
Pneumatic vs Electronic Controls 334
Process Chromatographs 335
SECTION FOUR: Operations 336
22. Troubleshooting 337
Introduction 338
Fractionation: Initial Checklists 338
Fractionator: Troubleshooting Checklist 340
Fractionation: Operating Problems 342
Fractionation: Mechanical Problems 348
Fractionation: Getting Ready for Troubleshooting 354
Fractionation: “Normal” Parameters 354
Fluid Flow 355
Refrigeration 359
Firetube Heaters 360
Safety Relief Valves 361
Gas Treating 362
Compressors 366
Measurement 368
23. Startup 369
Introduction 370
Settings for Controls 370
Probable Causes of Trouble in Controls 371
Checklists 373
24. Energy Conservation 377
Target Excess Oxygen 378
Stack Heat Loss 379
Stack Gas Dew Point 379
Equivalent Fuel Values 381
Heat Recovery Systems 382
Process Efficiency 383
Steam Traps 384
Gas Expanders 386
Fractionation 387
Insulating Materials 387
25. Shortcut Methods for Decisions 388
Introduction 389
Study Problem 389
Conclusions 396
26. Process Modeling Using Linear Programming 397
Process Modeling Using Linear Programming 398
27. Properties 403
Introduction 404
Approximate Physical Properties 404
Liquid Viscosity 405
Relative Humidity 409
Surface Tension 410
Gas Diffusion Coefficients 410
Water and Hydrocarbons 412
Natural Gas Hydrate Temperature 416
Inorganic Gases in Petroleum 418
Foam Density 420
Equivalent Diameter 421
Autoignition Temperature 423
Gibbs Free Energy of Formation 428
New Refrigerants 438
28. Approximate Conversion Factors 439
Approximate Conversion Factors 440
Appendixes 442
Appendix 1: Shortcut Equipment Design Methods—Overview 443
Appendix 2: Geographic Information Systems 445
Appendix 3: Archimedes’ Method Goes Modern 447
Appendix 4: Process Safety Management 448
Appendix 5: Do-It-Yourself Shortcut Methods 450
Appendix 6: Overview for Engineering Students 457
Appendix 7: Guidelines for Equipment Decisions 460
Appendix 8: Process Specification Sheets 473
Vessel data sheet 474
Shell and tube exchanger data sheet 475
Double pipe (G-fin) exchanger data sheet 476
Air-cooled (fin-fan) exchanger data sheet 477
Direct fired heater data sheet 478
Centrifugal pump (horizontal or vertical) data sheet 479
Pump (vertical turbine—can or propellor) data sheet 480
Tank data sheet 481
Cooling tower data sheet 482
Index 486