Natural Gas Processing Technology and Engineering Design Alireza Bahadori, Ph.D. School of Environment, Science and Engineering, Southern Cross University, Lismore, NSW, Australia AMSTERDAM BOSTON HEIDELBERG LONDON NEW YORK OXFORD PARIS SAN DIEGO SAN FRANCISCO SINGAPORE SYDNEY TOKYO ELSEVIER Gulf Professional Publishing is an imprini of Elsevier
Contents About the Author Preface xvii X1X CHAPTER 1 Overview of Natural Gas Resources i 1.1 The formation of natural gas 2 1.2 Conventional natural gas resources 3 1.3 Gas reservoir fluids 5 1.4 Unconventional natural gas resources 5 1.5 Hydraulic fracturing 15 Further reading 20 CHAPTER 2 Natural Gas Properties 23 CHAPTER 3 2.1 Fluid distribution in reservoir 23 2.2 Phase behavior of hydrocarbon systems 25 2.3 Pressure-volume-temperalure properties of hydrocarbon fluids 28 2.4 Gas compressibility factor 31 2.5 Equation of state 39 2.6 Gas specific gravity 43 2.7 Gas density 44 2.8 Specific volume 44 2.9 Isothermal compressibility of gases 44 2.10 Gas formation volume factor 45 2.11 Standard volume 47 2.12 Acentric factor 47 2.13 Viscosity 48 2.14 Thermal conductivity 50 2.15 Gross heating value of natural gases 53 References 56 Further reading 57 Single-phase and Multiphase Flow in Natural Gas Production Systems 59 3.1 Basic fluid flow theory 60 3.2 Process pipe sizing for plants located onshore single phase 64 3.3 Process pipe sizing for plants located offshore 79 3.4 Transmission pipelines ^4 3.5 Two-phase mixture properties 3.6 Two-phase flow pressure drop 3.7 General aspects in design of piping systems in oil, gas, and petrochemical plants 100 vii
viii Contents _, 3.8 Isometric drawings.. 105 3.9 Line identification list 3.10 Pipe supports 3.11 Pressure testing diagram 3.12 Tie-in diagram J^7 3.13 Above-ground piping systems 107 3.14 Valves 109 3.15 Flanges 3.16 Instrument piping 3.17 Sample systems 3.18 Vents and drains 118 3.19 Blow-down 119 3.20 Utility piping 119 3.21 Piping adjacent to equipment 128 3.22 Piping flexibility 136 3.23 Piping supports I37 3.24 Insulation 145 3.25 Piping connections to existing plant 146 3.26 Underground piping systems 146 References Further reading '47 ^ 112 11^ 117 '4V CHAPTER 4 Gas-Liquid Separators 151 4.1 Gravity settling 151 4.2 Gas-liquid separators in oil and gas processing 155 4.3 Conventional gas-liquid separators 157 4.4 Design criteria of separators 164 4.5 Gas-liquid separator sizing 166 4.6 Specification sheet 177 4.7 Mist eliminator type and installation point 179 4.8 Centrifugal gas-liquid separators 181 4.9 Flare knock-out drums 184 4.10 Gas-liquid filler separators 188 4.11 Process requirements of vessels, reactors, and separators 193 4.12 Nature of the feed 4.13 Solid-liquid separators 202 4.14 Typical equations, which can be used for terminal velocity calculation 208 4.15 Vessels Reference 193 213 220 Further reading 220 CHAPTER 5 Gas Compressors 223 5.1 Type selection criteria 5.2 Centrifugal compressors 226 225
Contents ix 5.3 Design criteria 231 5.4 Reciprocating compressors 235 5.5 Axial compressors 246 5.6 Screw compressors 247 5.7 Rotary compressors 248 5.8 Compressor cooling water jacket 249 5.9 Atmospheric pressure 249 5.10 Specification sheets 249 5.11 Material for axial and centrifugal compressors and expander-compressors 252 5.12 Centrifugal and axial compressors 264 5.13 Integrally geared compressors 267 5.14 Expander-compressors 269 Reference 271 Further reading 272 CHAPTER 6 Blow-Down and Flare Systems 275 6.1 Blow-down system for vapor relief stream 275 6.2 Blow-down system for liquid relief stream 276 6.3 Design of disposal system components 277 6.4 Sizing a knock-out drum 284 6.5 Quench drum 288 6.6 Flares 290 6.7 Burning pits 299 6.8 Determination of liquid level in a horizontal vessel 301 6.9 Sample calculation for sizing a flare stack 301 6.10 Process design of emergency measures 304 References 310 Further reading 310 CHAPTER 7 Safety Relive Valves Design 313 7.1 Provisions of pressure safety relief valves 313 7.2 Provisions of temperature safety valves 316 7.3 Provisions of vacuum safety valves 317 7.4 Provisions of rupture disks 317 7.5 Spare safety valves 318 7.6 Selection of type 319 7.7 Closed spring type valves 323 7.8 Safety valves with lifting devices 323 7.9 Temperature safety relief valves 323 7.10 Safety valve caps 7.11 Safely valve drains 324 7.12 Rupture disc types 324 7.13 Safety valve bonnet 324 324
x Contents 7.14 Set pressure 7.15 Pressure safety or relief valve set pressure 7.16 Temperature safety valve set pressure 7.17 Rupture disc set pressure 7.18 Vacuum relief valve set pressure 328 7.19 Sizing 329 7.20 Vacuum relief valve sizing QTQ JJO 7.21 Temperature safety valve sizing. 7.22 Rupture disc sizing 7.23 Emergency vapor depressuring systems 7.24 Arrangement of safety relief valves 340 7.25 Location on vessels 3^0 7.26 Location of safety valve nozzles to minimize turbulence 341 7.27 Location of safety valve nozzles to minimize pulsation 341 7.28 Inlet piping of safety relief valves 341 7.29 Discharge piping of safety relief valves 341 7.30 Block valves 343 7.31 Discharge piping support 7.32 Position 344 7.33 Discharge piping of temperature safety ii:> 327 3 338 Jjy 339 344 valves 344 7.34 Venting and draining philosophy 345 7.35 Vapor venting 345 7.36 Liquid venting 346 7.37 Safety valve bonnet venting 346 7.38 Safety valve draining 347 7.39 Sizing for gas or vapor relief 347 7.40 Sizing for liquid relief 352 7.41 Material and engineering for pressure and vacuum relief devices 354 7.42 Design of rupture disks 356 7.43 Material 357 7.44 Inspection and shop tests 359 7.45 Marking, documentation, and preparation for shipment 360 7.46 General specification for springs of pressure relief valves 362 7.47 Testing and dimensional checks 364 References 369 Further reading 369 CHAPTER 8 Sizing of Valve and Control Valve 371 8.1 Manual valves 371 8.2 Check valves 380 8.3 Control valves 382 8.4 Control valve sizing 383 8.5 Calculating Cv for liquids 388
Contents xi 8.6 Liquid sizing examples 396 8.7 Calculating Cv for gases 400 8.8 Calculating Cv for two phase flow 409 8.9 Engineering and material for control valves 411 8.10 Control valve body size and flange rating 424 8.11 Control valve characteristics 425 8.12 Control valve manifold design 427 8.13 Control valve block and bypass valves 428 8.14 Control valve packing and sealing 428 8.15 Control valve noise and vibration caused by sonic flow 429 8.16 Control valve actuators 431 8.17 Actuator construction materials 437 Further reading 438 CHAPTER 9 Natural Gas Dehydration 441 9.1 Phase behavior of dehydrated natural gas 442 9.2 Water content of natural gases 443 9.3 Gas water content prediction using generalized charts 444 9.4 Gas water content prediction using empirical methods 447 9.5 Methods based on EOS 452 9.6 Hydrates in natural gas systems 453 9.7 Thermodynamic model for the hydrate phase 456 9.8 Hydrate predictions for high C02/H2S content gases 458 9.9 Hydrate inhibition 460 9.10 Natural gas dehydration methods 465 9.11 Adsorption of water by a solid 474 References 477 Further reading 478 CHAPTER 10 Natural Gas Sweetening 483 10.1 Chemical solvent processes 483 10.2 Process selection 483 10.3 Chemical reaction processes 486 10.4 Simplified design calculations 495 10.5 General considerations 498 10.6 Corrosion in gas sweetening plants 503 10.7 Flash tank 504 10.8 Combined physical/chemical purification processes 504 10.9 Carbonate process 505 10.10 Physical absorption methods 507 10.11 Solid bed sweetening methods (batch Processes) 510 10.12 Process design 512 Reference 516 Further reading 516
xii Contents CHAPTER 11 Sulfur Recovery ^19 11.1 The Claus process 11.2 Technology overview 11.3 Acid gas enrichment 11.4 Oxygen enrichment 11.5 Reheat methods 11.6 Combustion operation 11.7 Sulfur condenser operation 11.8 Waste heat recovery operation 526 COQ C90 J- S9Q 11.9 Catalyst converter operation 530 11.10 Claus tail gas treating process selection 531 11.11 Contact condenser (two-stage quench) 538 11.12 Solvent selection criteria in the tail gas unit 541 11.13 Ammonia destruction in a TGU (RACTM) 544 11.14 BSRSelectox 545 Reference 545 Further reading 545 CHAPTER 12 Liquefied Petroleum Gas (LPG) Recovery 547 12.1 Properties 548 12.2 Natural gas liquids processing 548 12.3 Fractionation 553 12.4 Packed columns 558 12.5 Basic design requirements 560 12.6 Fractionation and system configuration 564 12.7 Absorption/stripping 566 12.8 Control and optimization 566 12.9 Storing and handling of liquefied petroleum gases (LPGs) 566 12.10 Design considerations 570 12.11 Transfer of LPG within the off-site facilities of oil and gas processing (OGP) plants 576 12.12 Pressure storage spheres for LPG 577 12.13 Material selection 578 12.14 General information 579 12.15 Design of pressure storage spheres 580 12.16 Nozzles and connections 585 12.17 Mountings 587 12.18 Access facilities 588 12.19 Fabrication 589 12.20 Insulation 589 Reference 590 Further reading 590
Contents xiii CHAPTER 13 Liquefied Natural Gas (LNG) 591 13.1 The LNG chain 593 13.2 The LNG liquefaction facility 593 13.3 Liquefaction process 593 13.4 LNG storage 594 13.5 In-tank pump process objectives 594 13.6 LNG shipping 595 13.7 Liquefaction and refrigeration 595 13.8 Basic single flow LNG process 605 13.9 Multistage MR process 605 13.10 Mixed fluid cascade process 606 13.11 Classification of natural gas liquefaction processes 606 13.12 Type of LNG plants 616 13.13 Liquefaction cycle for LNG FPSO 617 13.14 Proposed LNG liquefaction processes for FPSO 622 13.15 Storage and transfer facilities of LNG 627 References 631 Further reading 631 : CHAPTER 14 Basic Engineering Design for Natural Gas Processing Projects 633 14.1 Contents of BEDP 634 14.2 Items common for all units 634 14.3 Manuals 639 14.4 Individual items for each unit 641 14.5 Specifications and data sheets 642 14.6 Drawings 648 14.7 Recommended practice for feasibility studies 648 14.8 Prefeasibility studies 652 14.9 Outline of prefeasibility study 653 14.10 Feasibility studies 656 14.11 Production program and plant capacity 667 14.12 Technology choice 668 14.13 Selection of machinery and equipment 670 14.14 Civil engineering works 670 14.15 Estimates of overall investment costs (capital cost estimates) 671 14.16 Organization and overhead costs 676 14.17 Human resources 678 14.18 Implementation, planning, and budgeting 680 14.19 Financial analysis and investment appraisal 681 14.20 Method of investment appraisal 687 14.21 Break-even analysis 694 14.22 Preparation of basic engineering design data 696
xiv Contents 14.23 Data preparation of utilities (utility summary tables) 710 14.24 Data preparation of effluents 716 14.25 Data preparation of catalysts and chemicals 7)7 Further reading CHAPTER 15 Detailed Engineering and Design for Natural Gas Processing Projects 723 15.1 Detailed implementation plan 723 15.2 Project schedule and control services 724 15.3 Quality assurance and control 7^0 15.4 Detailed design and engineering 731 15.5 Procurements services 15.6 Supply of materials 749 15.7 Detail design & engineering documents "750 15.8 Supply of spare parts, miscellaneous equipment and materials, chemicals and catalysts 15.9 Reimbursable items 755 15.10 Process flow diagram (PFD) and piping and instrumentation diagrams 756 15.11 Identification and numbering of equipment 760 15.12 Description of equipment 761 15.13 Description of instrumentation 763 15.14 Material balance table "767 15.15 Piping and equipment symbols 769 15.16 Piping & instrumentation diagrams (P&IDs) 769 15.17 Minimum information to be shown on P&IDs 775 15.18 Equipment indication 775 15.19 Instrumentation 781 15.20 Piping 782 15.21 Special requirements 782 15.22 General notes 784 15.23 Design criteria for preparation of P&IDs 786 15.24 Bypass for safety/relief valve 787 15.25 Criteria lor utility flow diagrams 789 15.26 Preparation of P&IDs 15.27 Handling of licensed process 797 15.28 Revisions of P&1D 15.29 Block and bypass valves for control valve 799 15.30 Philosophy of instrumentation installation 800 Further reading 801 1A~\ 7^3 790 798 CHAPTER 16 Start-up Sequence and Commissioning Procedures 803 16.1 Preparation prior to initial start-up 804 16.2 Final inspection of vessels 8] ]
Contents xv 16.3 Flushing of lines 812 16.4 Instruments 814 16.5 Acid cleaning of compressor lines 814 16.6 Breaking-in pumps 8' 5 16.7 Breaking-in compressors 816 16.8 Dry-out and boil-out 817 16.9 Catalyst loading 820 16.10 Tightness test 820 16.11 Normal start-up procedures 821 16.12 Catalytic units reactor section air purging and gas blanketing 823 16.13 Heat exchanger activation 824 16.14 Vacuum test 824 16.15 Establish flow in the unit 824 16.16 Inhibitor/chemical injections 824 16.17 Typical acid cleaning procedure for compressor lines 824 16.18 The acid-cleaning operation 825 16.19 Typical healer dry-out procedure 826 16.20 Typical chemical boil-out sequence 828 16.21 Basic considerations in preparing operating manuals 829 16.22 Safety manual/quality manual 830 16.23 Non-licensed processes 831 16.24 Noteworthy points 831 16.25 Design basis 832 16.26 Plant technical and equipment manuals 837 Further reading 83^ Glossary of Terms 841 Index 853