LNG Risk Based Safety: Modeling and Consequence Analysis

LNG RISK BASED SAFETY......Page 3
CONTENTS......Page 9
Preface......Page 17
1 LNG Properties and Overview of Hazards......Page 19
1.1 LNG Properties......Page 20
1.2 Hazards of LNG with Respect to Public Risk......Page 22
1.2.1 Flash Fire, Pool Fire, or Jet Fire......Page 25
1.2.2 Outdoor Vapor Cloud Explosions......Page 26
1.2.5 Freeze Burns......Page 27
1.3 Risk Analysis Requires Adequate Modeling......Page 28
1.4 Flammability......Page 29
1.5.1 U.S. Marine LNG Risk and Security Regulation......Page 31
1.5.2 U.S. Land-Based LNG Risk and Security Regulation......Page 32
1.5.3 European and International Regulations......Page 33
1.7 Controversial Claims of LNG Opponents......Page 34
2.1 LNG Ship Design History......Page 38
2.1.4 Tank Design......Page 39
2.2 Designs and Issues—First Commercial LNG Ships......Page 40
2.2.1 Membrane Technology......Page 41
2.2.2 Gaztransport Solution......Page 42
2.2.3 Spheres......Page 43
2.2.4 LNG Carriers for the Asian Trade......Page 44
2.3.1 European Trade......Page 45
2.3.4 Revival of LNG with Worldwide Supply–Demand Pinch of Petroleum......Page 46
2.3.5 Supply History......Page 47
2.3.6 Some Economic Factors......Page 48
2.4 LNG Accident History......Page 50
2.5 Summary of LNG History and Relevant Technical Developments......Page 53
3 Current LNG Carriers......Page 55
3.2.1 Tank Design and Insulation......Page 57
3.2.2 Dimensions and Capacity......Page 59
3.2.3 Tank Materials and Insulation......Page 60
3.2.5 Design Issues......Page 62
3.3 Moss Spheres......Page 64
3.3.1 Typical Dimensions and Capacity......Page 65
3.3.4 Design Issues......Page 66
4 Risk Analysis and Risk Reduction......Page 68
4.1 Background......Page 69
4.2 Risk Analysis Process......Page 70
4.2.1 Hazard Identification......Page 72
4.3.1 Generic Data Approach......Page 75
4.4 Frequency: Predictive Methods......Page 76
4.4.1 FTA......Page 77
4.4.2 Event Tree Analysis......Page 78
4.6 Ignition Probability......Page 82
4.7.1 Risk Presentation......Page 86
4.8 Special Issues—Terrorism......Page 88
4.9 Risk Reduction and Mitigation Measures for LNG......Page 89
5 LNG Discharge on Water......Page 92
5.1.1 Ship-to-Ship Collisions......Page 94
5.1.2 Weapons Attack......Page 98
5.2.2 Explosive-Laden Boat Attack......Page 99
5.3 Type 3—Below Waterline Breaches at Sea......Page 102
5.4 Discharges from Ship’s Pipework......Page 103
5.5.1 Sloshing Forces......Page 104
5.5.4 Cryogenic Temperature Stresses on Decks and Hull......Page 105
5.6 Initial Discharge Rate......Page 106
5.7.1 Blowdown for Type 2 Breach (at Waterline)......Page 108
5.7.2 Blowdown for Type 1 Breach (above Waterline)......Page 110
5.7.3 Blowdown of Type 3 Breach (Underwater Level)......Page 112
5.8 Vacuum Breaking and Glug-Glug Effects......Page 121
6.1 Typical Basis for LNG Receiving Terminal......Page 122
6.2 Features of LNG Receiving Terminals......Page 123
6.3 Standards for Receiving Terminal Design......Page 128
6.4 U.S. Guidelines and Regulations for Receiving Terminals......Page 130
6.4.2 LNG Terminal Permitting by Federal Energy Regulatory Commission (FERC)......Page 131
6.4.3 Pool Fire Radiation Exclusion Zone......Page 132
6.4.4 Vapor Dispersion Exclusion Zone......Page 134
6.5.1 Features of EN 1473......Page 137
6.5.2 Comparison of Prescriptive and Risk-Based Approaches......Page 138
6.6 Empirical Formula for Required Land Area of Terminal......Page 139
6.7 Leak in Loading Arm or in Storage Tank......Page 141
6.7.1 Modeling Effects of Substrate on Evaporation Rate......Page 142
6.7.2 Vapor Hold-Up Effect on Dispersion Zone Calculation......Page 144
6.8 Rollover......Page 147
6.10 Offshore LNG Terminals......Page 150
7 LNG Pool Modeling......Page 152
7.1 Flashing and Droplet Evaporation in Jet Flow......Page 153
7.2 Pool Spread and Evaporation Modeling......Page 154
7.2.1 Spread Rate on Smooth Surface......Page 156
7.2.3 Pool Evaporation on Smooth Water Surface, Test Data......Page 162
7.2.4 Pool Evaporation, Heat Transfer Regimes......Page 163
7.2.5 Heat Conduction on Shallow Water with Ice Formation......Page 168
7.2.6 Composition Changes with Evaporation......Page 169
7.2.7 Type 1 Breach—LNG Penetration into Water, Turbulent Heat Transfer......Page 171
7.2.8 Time-Dependent Pool Spread......Page 174
7.3 Rapid Phase Transition Explosions......Page 177
7.3.1 Historical Experience with LNG RPTs......Page 178
7.3.2 Similar Phenomena More Thoroughly Investigated......Page 179
7.3.4 Models of RPT Explosions......Page 180
7.3.5 Superheat Limits......Page 183
7.4 Aerosol Drop Size......Page 184
7.4.1 Drop Size Distribution......Page 185
7.4.2 Droplet Breakup Mechanisms......Page 186
7.5.1 Heat Conduction from Solid Substrate......Page 187
7.5.3 Radiation to/from Pool......Page 188
7.5.5 Bubble Flow in Vaporizing LNG......Page 189
7.6 Nomenclature......Page 190
8.1 Atmospheric Transport Processes......Page 193
8.1.1 Wind Speed, Stability, and Surface Roughness......Page 194
8.2 Model Types......Page 199
8.2.1 Gaussian Models......Page 200
8.2.2 Integral or Similarity Models......Page 201
8.2.3 CFD......Page 203
8.3 LNG Dispersion Test Series......Page 206
8.4.1 Heavy Gas Properties Increase Hazard Area......Page 211
8.4.2 Models Predict Average Conditions of Fluctuating Plume......Page 215
8.4.3 Wind Speed for Longest Plume......Page 219
8.4.5 Scooping of Confined Vapors......Page 220
8.5 Effect of Wind, Currents, and Waves on LNG Plume......Page 222
8.6 Comparison of Dispersion Model Predictions......Page 223
8.7.2 Shell Jettison Tests......Page 227
8.7.4 Maplin Sands Test Series......Page 228
8.7.5 Falcon Test Series......Page 229
8.8.1 Basic Response for Indoor Concentration Buildup......Page 230
8.8.3 Concentration Reduction by Plume Impinging on Buildings......Page 232
8.8.4 Models of Infiltration into Buildings......Page 233
8.9 Theoretical Basis for Suppression of Turbulence......Page 238
9.1 Types of Fires from LNG Facilities......Page 240
9.3.1 Fires Are Low-Momentum Phenomena......Page 241
9.3.2 Fire Structure......Page 243
9.3.3 Simplifying Pool Fire Structure......Page 246
9.5 Burning Rate Data and Correlations From Fire Tests......Page 248
9.5.2 Stopping Point for Pool Fire......Page 254
9.6 Point Source Fire Model......Page 255
9.7 Solid Flame Models: Flame Length Correlations......Page 257
9.7.1 Small-Scale Pool Fire Tests and Flame Length Correlations......Page 258
9.7.2 Medium-Scale Pool Fire Tests and Flame Length Correlations......Page 263
9.7.3 Large-Scale Pool Fire Tests and Flame Length Correlations......Page 266
9.8 Flame Tilt Correlations......Page 267
9.9 Flame Drag Near Pools......Page 270
9.10.1 SEP from Tests......Page 271
9.10.2 Smoke Shielding and Theoretical SEP Values......Page 272
9.11 Atmospheric Transmissivity......Page 277
9.12 Trench Fires......Page 280
9.13 View Factors......Page 282
9.14 CFD Modeling......Page 284
9.15 Comparison of Model Predictions......Page 286
9.16 Fire Engulfment of LNG Carrier......Page 289
10.1 Fire and Explosion Scenarios......Page 293
10.2 Jet Fires......Page 294
10.3 Flash Fires......Page 304
10.4 BLEVEs, Fireballs......Page 309
10.4.1 BLEVEs and Applicability to LNG......Page 310
10.4.2 Applicability of BLEVEs to LNG Marine Vessels......Page 312
10.4.3 Fireballs from Released Vapor......Page 315
10.5 LNG Vapor Cloud Explosions......Page 320
10.5.1 Characteristics of Detonations and Deflagrations......Page 321
10.5.2 Fuel Reactivity Effects......Page 324
10.5.3 Modeling VCEs......Page 326
10.5.4 CFD Modeling of VCEs......Page 329
10.6 Asphyxiation and Cryogenic Hazard from LNG Spills......Page 331
11.1.1 Injuries to People—Definition of Burn Degrees......Page 336
11.1.2 Measured Effect Levels from Radiation Exposure......Page 337
11.1.3 Thresholds of Injury on Thermal Dose Basis......Page 340
11.2.1 Equipment Degradation by Thermal Radiation......Page 342
11.2.2 Thermal Weakening of Steel and Concrete......Page 343
11.2.3 Bursting Pressure Vessels, Rail Tank Cars......Page 345
12.1 Uncertainties......Page 347
12.2 Recommendations of GAO Survey......Page 348
12.3 LNG Model Evaluation Protocols (MEPs)......Page 351
12.4.1 LNG Pool Spill and Fire Tests......Page 353
12.4.3 LNG Plumes Not Modeled Well for Calm Winds......Page 355
12.4.4 The Use of ½ LFL as an End Point......Page 356
12.5 Conclusions......Page 357
References......Page 359
Index......Page 387