Turboexpanders and Process Applications

Contents......Page 1
Dedication......Page 3
Preface......Page 4
1 Why and How Turboexpanders Are Applied......Page 9
TURBOEXPANDERS FOR ENERGY CONVERSION*......Page 10
TURBOEXPANDER APPLICATIONS......Page 11
POWER RECOVERY TURBOEXPANDERS......Page 12
2 Turboexpander Fundamentals......Page 27
SPECIFIC CRYOGENIC APPLICATIONS......Page 38
STATISTICAL ASPECTS OF TURBOEXPANDER REQUIREMENTS......Page 41
RADIAL REACTION VERSUS IMPULSE DESIGN......Page 43
EFFICIENCY AND SIZING CALCULATIONS......Page 44
OPTIMIZING EFFICIENCY IN METHANE LIQUEFACTION......Page 50
Thermodynamics......Page 51
EXAMPLE PROCESS......Page 52
Temperature Differences......Page 54
Work Inputs......Page 55
Efficiencies......Page 57
Process Refinement......Page 59
COMPARISON OF EXPANDER AND CASCADE CYCLES FOR LNG......Page 60
Cascade Cycles......Page 64
ETHYLENE PLANT EXPANDERS......Page 66
Expander Efficiency......Page 68
MECHANICAL RELIABILITY......Page 70
High Efficiency Boosters......Page 71
Automatic Thrust Balance System......Page 72
Turboexpanders Equipped with Magnetic Bearings......Page 74
Shaft and Bearing Design......Page 75
ECONOMICS OF TURBOEXPANDERS IN CLEAN APPLICATIONS......Page 76
GAS TREATING METHODS......Page 77
THERMODYNAMIC BEHAVIOR OF HYDROGEN/ NATURAL GAS MIXTURES......Page 81
Ethylene and Propylene Plants......Page 84
Hydrogen Purification......Page 85
ROTOR SYSTEMS FOR TURBOEXPANDERS IN LNG PLANTS......Page 86
MAGNETIC BEARING ROTOR SYSTEMS......Page 87
TURBOEXPANDER AVAILABILITY......Page 88
NITRIC ACID PRODUCTION1......Page 93
Oxidation......Page 96
Absorption......Page 97
Acid Concentrations......Page 98
Plant Pressure Level Considerations......Page 99
Centrifugal Compressors......Page 107
Axial Compressors......Page 110
SELECTION AND DESIGN OF TAIL GAS EXPANDERS......Page 114
Uncooled Expanders......Page 120
SELECTING A PRIME MOVER FOR TURBOTRAINS IN NITRIC ACID PLANTS......Page 122
Design Considerations......Page 126
Turbotrain Safety Systems......Page 132
Startup Procedures......Page 134
INTEGRALLY GEARED PROCESS GAS RADIAL TURBINES2......Page 137
TURBOEXPANDERS IN GEOTHERMAL APPLICATIONS*......Page 144
THE BEN HOLT PROCESS DESIGN......Page 145
Unique Design Features for Geothermal Energy Recovery Applications......Page 146
PROCESS OVERVIEW......Page 149
REACTOR DESCRIPTION......Page 150
Catalyst Separation......Page 153
Stripping Section......Page 155
REGENERATOR DESCRIPTION......Page 156
Standpipe and Slide Valve......Page 158
Catalyst Separation......Page 159
Flue Gas Heat Recovery Schemes......Page 160
Catalyst Types......Page 161
DESIGN ISSUES RELATING TO FCC TURBOEXPANDERS......Page 163
Low and High Pressures......Page 166
Design Guides......Page 168
Regenerator Pressure......Page 171
Carbon Dioxide and Monoxide Ratios......Page 175
Power Failure......Page 176
Operator Response......Page 177
Power System Stability......Page 178
Application Concerns......Page 181
POWER GENERATION FOR THE FCC PROCESS......Page 183
String Arrangements......Page 184
Generator Type......Page 185
Valve Systems......Page 188
Startup......Page 189
Overspeed Protection......Page 191
FCC DYNAMIC COMPUTER SIMULATIONS......Page 193
Power Recovery Strings ( PRS)......Page 195
Generator Load Drop......Page 198
Control Valve Malfunction......Page 199
Coupling Break......Page 201
Generator Load Drop......Page 202
Valve Closure Study......Page 203
MICROPROCESSOR- BASED TURBOMACHINERY MANAGEMENT SYSTEMS......Page 204
EDS Hardware......Page 205
MACS PACK......Page 207
Expansion Packages......Page 210
LASER SENTRY......Page 211
General Description......Page 212
POWER RECOVERY EXPANDER REPAIR......Page 213
ECONOMIC EVALUATION OF FCC TURBOMACHINERY ALTERNATIVES......Page 218
Basis and Assumptions for Example......Page 220
Aerodynamic Design......Page 230
Velocity Ratio......Page 231
Stage Reaction......Page 234
Leakage and Secondary Losses......Page 235
Gas Conditions......Page 237
MATERIAL SELECTION FOR POWER RECOVERY TURBINES......Page 241
HOT CORROSION OF WASPALOY MATERIAL IN GAS EXPANDER ROTATING COMPONENTS......Page 244
Fracture Mechanism......Page 246
Determining Susceptibility of Ni3S2 Formation Using a Hot Gas Expander Analysis Mechanism of SOx Attack on Waspaloy......Page 247
Determining Susceptibility of Ni3S2 Formation Using a Stability Diagram......Page 248
Preventive Measures to Eliminate Ni3S2 Formation......Page 249
Sulfidation- Resistant Nickel- Base Superalloy for FCC Flue Gas Expanders......Page 250
TURBOEXPANDER TESTING......Page 251
SOLID PARTICLE EROSION......Page 254
POWER RECOVERY AND THE EDDY CURRENT BRAKE......Page 268
MODES OF OPERATION......Page 277
DESIGN CONSIDERATIONS Off- Design Performance......Page 281
Sealing Systems......Page 282
Compressor Diffuser......Page 283
Vibration Monitoring Probes......Page 284
Lube Oil Coolers......Page 285
Lube Oil Reservoir Heater......Page 286
Documentation and Testing Set Points for Alarms and Shutdowns......Page 287
Compressor Performance Test......Page 288
EXPANDER UPGRADE AND REDESIGN EXPERIENCE......Page 289
Leakage of Oil into the Process......Page 292
Loss of Expander Control Due to Abrasion of Nozzle Against Pins......Page 294
Loss of Expander Control Due To Nozzle Segment/ Adjusting Ring Galling......Page 295
Transient or Chronic Rotor Imbalance Due to Cylindrical or Splined Wheel- to- Shaft Attachments......Page 296
TYPICAL EXPANDER- COMPRESSOR STARTUP......Page 299
Startup Tips to Minimize Expander Problems......Page 301
1.0 General Information 1.1 Scope......Page 305
1.3 Definition of Terms......Page 307
2.0 Expander 2.1 General......Page 308
2.2 Vibration and Balance......Page 311
2.3 Rotor Assembly......Page 312
2.4 Inlet Casing......Page 315
2.5 Exhaust Casing......Page 319
2.6 Bearing Housing......Page 321
2.7 Expander Construction Materials......Page 323
2.8 Testing and Checks......Page 324
3.0 Welding......Page 326
5.0 Alarms and Shutdown Provisions......Page 327
7.0 Spare Parts......Page 328
8.0 Drawings and Documents......Page 329
GUIDELINES FOR FIELD- TESTING HOT GAS TURBOEXPANDERS......Page 330
1. General......Page 331
2. Performance Test......Page 332
3. Instrumentation......Page 333
BASIC PRINCIPLES OF ACTIVE MAGNETIC BEARINGS......Page 341
Operating Principles and Design Features Radial Bearings......Page 343
Turboexpander Applications for Active Magnetic Bearings......Page 344
CASE STUDIES ON ACTIVE MAGNETIC BEARINGS ( AMB) AND DRY GAS SEALS ( DGS)......Page 345
Magnetic Bearing Housing Sealing and Cooling Loop Control......Page 346
Pressurized Bearing Housing ( Offshore Application)......Page 347
Dry Face Seal Application, Atmospheric Bearing Housing ( Onshore Application)......Page 348
Magnetic Bearing Winding Loss......Page 349
Bearing Housing Temperature Control......Page 350
Thrust Balancing Control......Page 352
Automatic Clamping System Control......Page 354
Turboexpanders with Dry Gas Seals.......Page 356
Turboexpanders with Active Magnetic Bearings Revisited.......Page 360
Turboexpanders with AMB and DGS.......Page 364
SQUEEZE FILM DAMPERS4......Page 367
Squeeze Film Dampers without a Centering Spring......Page 368
Elastomeric O- Ring Supported Dampers......Page 370
Squirrel Cage Supported Dampers......Page 371
Integral Damper- Centering Spring......Page 372
Optimization for Improved Stability......Page 373
Control of Critical Speeds......Page 377
RADIAL FIT BOLTS5......Page 378
HYDRAULIC BOLT......Page 379
ALIGNMENT TOOL......Page 380
Full Main Air Blower Train Valve Arrangements......Page 381
Two Valve Arrangement......Page 382
Four Valve Arrangement......Page 383
Total Power Generation Train......Page 385
Three Valve TPG Arrangement......Page 386
FCC EXPANDER LOAD SHEDDING CONTROL7......Page 388
Regenerator Pressure Control......Page 390
Dynamic Simulation......Page 392
The Turbolog DSP System......Page 393
Controller Structure......Page 395
Switching Between Control Characteristics......Page 396
Commissioning of the Power Recovery Train......Page 397
Understanding Surge......Page 398
Closed- Loop Surge Protection......Page 400
Limit Line and Surge Control Line.......Page 401
Open- Loop Control......Page 402
Minimizing Process Upsets......Page 405
Complex Antisurge Protection......Page 406
Antisurge Valve Requirements......Page 407
Capacity Control......Page 408
MAINTENANCE STRATEGIES......Page 409
PREDICTIVE STRATEGY......Page 410
PRT LOAD SHEDDING CONCERNS......Page 411
What Is Needed......Page 412
Expander Operation and Control......Page 413
Expander Characteristics......Page 414
Breaker Trip Triggers Open- loop Control......Page 415
Closing the Inlet Valve and Opening the Bypass Valve......Page 417
Method Simplification......Page 426
Guide Basis......Page 427
Warning:......Page 429
TURBOEXPANDER DESIGN AND PERFORMANCE......Page 436
Constant Speed Turboexpander......Page 439
Hydrocarbon Extraction......Page 441
Turboexpander Redesign Concepts......Page 443
Break- even Analysis......Page 444
NOMENCLATURE......Page 445
Definitions:......Page 446
CASE 1: CRYOGENIC TECHNOLOGY HELPS OPTIMIZE PRODUCTIVITY1......Page 448
CASE 2: TURBOEXPANDERS INSTALLED AT AN OLDER METHANOL PRODUCING PLANT PROVIDE MAJOR ENERGY SAVINGS......Page 450
CASE 3: MANUFACTURE OF COPPER AND MOLYBDENUM......Page 452
HOW THE PROCESS WORKS......Page 453
BACKGROUND DATA......Page 455
CASE 5: LNG PARALLEL EXPANDERS......Page 456
CASE 6: NEW GAS RESERVOIR PRODUCTION WITH OFFSHORE OIL SITE......Page 458
CASE 7: NATURAL GAS Ï STRADDLEÓ PIPELINE APPLICATION......Page 0
REDUCING THE PRESSURE WITH EXPANSION TURBINES......Page 462
CASE 8: A NEW H2O2 PLANT DESIGN......Page 463
CASE 9: USE OF MAGNETIC BEARINGS BY NORSKE SHELL IN AN ONSHORE APPLICATION......Page 464
CASE 11: ETHYLENE PLANT IN KUWAIT......Page 468
CASE 12: MTBE PLANT IN TEXAS......Page 470
CASE 13: MORE ENERGY FOR A PHENOL PLANT......Page 471
CASE 14: IMPROVING FCC EXPANDER RELIABILITY UNDER OFF- DESIGN CONDITIONS2......Page 472
CASE 15: GENERATING ELECTRICITY FROM EXCESS ENERGY WITH A LETDOWN GAS COMPRESSOR......Page 479
OPERATING AND MAINTENANCE HISTORY......Page 484
ECONOMIC ANALYSIS......Page 486
CASE 16: THE USE OF MAGNETIC BEARINGS FOR OFFSHORE APPLICATIONS......Page 489
Conversion Tables......Page 493
Turboexpander Specifications......Page 494
Turboexpander Contacts and Addresses......Page 497
Index......Page 506