1 Basic concepts of Integrity Management................................................................. 1
1.1 Integrity and Integrity Assurance......................................................................... 1
1.2 Awareness and knowledge of threats to integrity................................................. 1
1.3 Barriers against threats to integrity.................................................................... 3
1.4 Manmade risks.................................................................................................... 4
1.5 Audits.................................................................................................................... 4
1.6 Risk and RBI.......................................................................................................... 4
1.7 Maturity of the HF Alkylation process.................................................................. 5
1.8 References............................................................................................................. 6
2 The HF Alkylation process and its use..................................................................... 7
2.1 History of the gasoline alkylation process............................................................ 7
2.2 Alkylation chemical reactions and catalyst........................................................... 8
2.3 UOP and Phillips designed HF Alkylation units.................................................... 9
2.4 Typical mass balance of a HF Alkylation unit........................................................ 21
2.5 Global operating HF Alkylation capacity............................................................. 22
2.6 Typical upgrading margin of Alkylation units...................................................... 23
2.7 API Recommended Practice 751.......................................................................... 24
2.8 Properties of anhydrous hydrofluoric acid......................................................... 25
2.9 World production and use of HF acid................................................................. 26
2.10 References........................................................................................................ 29
3 Corrosion Mechanisms in HF-environment.................................................... 31
3.1 Properties of anhydrous HF acid......................................................................... 31
3.2 Properties of trace acid streams......................................................................... 31
3.3 Fluoride scale on steel....................................................................................... 32
3.4 Measured corrosion rates of C-steel in HF/H2O mixtures..................................... 35
3.5 The effect of temperature.................................................................................. 37
3.6 Residual elements and corrosion........................................................................ 38
3.7 Occluded corrosion cells.................................................................................. 41
3.8 Corrosion due to mechanical failure of the fluoride scale.................................... 43
3.9 Formation of dilute acid in the process............................................................... 43
3.10 Corrosion of austenitic and nickel rich alloys..................................................... 46
3.11 Hydrogen embrittlement and cracking of steel.................................................... 47
3.12 Corrosion of copper alloys and Alloy 400........................................................... 51
3.13 Stress corrosion cracking of Alloy 400 and Ni-alloys.......................................... 52
3.14 Effect of mercury on Alloy 400.......................................................................... 53
3.15 Galvanic attack................................................................................................ 53
3.16 Caustic embrittlement....................................................................................... 54
3.17 External corrosion........................................................................................... 54
3.18 Cases................................................................................................................ 54
3.19 Main fractionator feed heat exchanger bundles.................................................. 61
3.20 Summary and evaluation................................................................................... 65
3.21 References........................................................................................................... 65
4 Process design aspects affecting integrity............................................................. 67
4.1 Feedstock treating................................................................................................ 67
4.2 Segregation of the HF section from non-HF sections......................................... 69
4.3 Process design issues affecting integrity............................................................. 72
4.4 Process safeguarding issues affecting integrity................................................... 82
4.5 Management of change......................................................................................... 83
4.6 Miscellaneous design issues affecting integrity.................................................... 83
4.7 References.............................................................................................................. 84
5 Materials selection and equipment design............................................................. 85
5.1 Carbon steel and ferrous materials...................................................................... 85
5.2 Nickel-copper alloys............................................................................................. 87
5.3 Other metals......................................................................................................... 90
5.4 Non-metals in HF-alkylation service................................................................... 91
5.5 Pressure vessels................................................................................................... 94
5.6 Piping systems...................................................................................................... 96
5.7 Flexible piping and hoses................................................................................... 100
5.8 Bolting................................................................................................................. 101
5.9 Heat exchange systems..................................................................................... 103
5.10 Pumps................................................................................................................. 115
5.11 Instruments......................................................................................................... 120
5.12 Pressure relief valves and bursting disks........................................................... 121
5.13 Storage facilities.................................................................................................. 121
5.14 References.......................................................................................................... 122
6 Operations and Integrity Management.................................................................. 125
6.1 Feedstocks and feedstock contaminants............................................................ 125
6.2 Acid management................................................................................................ 129
6.3 Products and product treatment........................................................................ 142
6.4 ASO disposal........................................................................................................ 146
6.5 Operating procedures......................................................................................... 146
6.6 Monitoring of the HFA unit operation................................................................. 159
6.7 Performance health check of HFA unit.............................................................. 162
6.8 Integrity Operating Windows.............................................................................. 162
6.9 Typical equipment fouling problems.................................................................. 164
6.10 Miscellaneous aspects......................................................................................... 168
6.11 References........................................................................................................... 172
7 Monitoring and Inspection...................................................................................... 173
7.1 General inspection strategy.................................................................................. 173
7.2 Specific inspection strategy for HF alkylation.................................................... 173
7.3 Corrosion loops..................................................................................................... 174
7.4 Monitoring.............................................................................................................. 175
7.5 Non-intrusive inspection programs (NII)............................................................ 175
7.6 Non-intrusive inspection techniques................................................................. 176
7.7 Internal visual inspection (IVI).............................................................................. 177
7.8 Waiving periodic internal visual inspection........................................................ 178
7.9 References.............................................................................................................. 179
8 Mitigation of Consequences.................................................................................... 181
8.1 HF release and dispersion tests......................................................................... 181
8.2 Leak detection in an HFA unit............................................................................ 183
8.3 Active mitigation measures................................................................................ 187
8.4 Passive mitigation measures............................................................................. 194
8.5 HF release emergency preparedness................................................................... 196
8.6 Eliminating HF.................................................................................................... 198
8.7 Conclusion on eliminating HF........................................................................... 199
8.8 References...................................................................................................... 199
9 Assessment of residual risk and cost effectiveness of risk mitigation measures.. 201
9.1 Assessment of the residual risk of the HFA unit.................................................. 201
9.2 Results from comparative QRA studies of HFA units........................................... 204
9.3 Measures to reduce the residual HF risk...............................................................204
9.4 Summary................................................................................................................ 207
9.5 References..............................................................................................................207
10 HF release incidents.............................................................................................. 209
10.1 Causes of HF release incidents in refinery HF Alkylation units.............................. 209
10.2 HF release incidents in the refining HF Alkylation units....................................... 210
10.3 Incidents during transport of HF............................................................................ 224
10.4 HF-release incidents outside the oil industry...................................................... 224
11 Overview of worldwide operating HF Alkylation units........................................ 229
11.1 Operating HFA unit capacity per global region................................................... 229
11.2 Company HFA unit capacity................................................................................. 229
11.3 References............................................................................................................. 230
12 World operating hf alkylation units – Status Year 2013....................................... 231
13 Nomenclature....................................................................................................... 234