Gas pipeline hydraulics

Contents Chapter 1 Gas Properties 1.1 Mass and Weight..............................................................................................1 1.2 Volume..............................................................................................................2 1.3 Density, Specific Weight, and Specific Volume ..............................................3 1.4 Specific Gravity................................................................................................3 1.5 Viscosity ...........................................................................................................4 1.6 Ideal Gases .......................................................................................................9 1.7 Real Gases......................................................................................................14 1.8 Natural Gas Mixtures.....................................................................................16 1.9 Pseudo-Critical Properties from Gas Gravity................................................19 1.10 Impact of Sour Gas and Non-Hydrocarbon Components.............................20 1.11 Compressibility Factor ...................................................................................21 1.11.1 Standing-Katz Method .....................................................................22 1.11.2 Dranchuk, Purvis, and Robinson Method .......................................23 1.11.3 American Gas Association (AGA) Method.....................................23 1.11.4 California Natural Gas Association (CNGA) Method ....................24 1.12 Heating Value .................................................................................................27 1.13 Summary ........................................................................................................27 Problems ..................................................................................................................28 References................................................................................................................29 Chapter 2 Pressure Drop Due to Friction 2.1 Bernoulli’s Equation ......................................................................................31 2.2 Flow Equations...............................................................................................32 2.3 General Flow Equation ..................................................................................33 2.4 Effect of Pipe Elevations ...............................................................................35 2.5 Average Pipe Segment Pressure ....................................................................37 2.6 Velocity of Gas in a Pipeline.........................................................................37 2.7 Erosional Velocity ..........................................................................................40 2.8 Reynolds Number of Flow.............................................................................43 2.9 Friction Factor................................................................................................45 2.10 Colebrook-White Equation ............................................................................47 2.11 Transmission Factor .......................................................................................50 2.12 Modified Colebrook-White Equation ............................................................54 2.13 American Gas Association (AGA) Equation.................................................57 2.14 Weymouth Equation.......................................................................................61 2.15 Panhandle A Equation....................................................................................64 2.16 Panhandle B Equation....................................................................................68 2.17 Institute of Gas Technology (IGT) Equation ................................................70 2.18 Spitzglass Equation ........................................................................................74 2.19 Mueller Equation............................................................................................76 2.20 Fritzsche Equation..........................................................................................77 2.21 Effect of Pipe Roughness ..............................................................................78 Copyright 2005 by Taylor & Francis Group, LLC 2.22 Comparison of Flow Equations .....................................................................80 2.23 Summary ........................................................................................................81 Problems ..................................................................................................................82 References................................................................................................................83 Chapter 3 Pressure Required to Transport 3.1 Total Pressure Drop Required........................................................................85 3.2 Frictional Effect .............................................................................................86 3.3 Effect of Pipeline Elevation ...........................................................................86 3.4 Effect of Changing Pipe Delivery Pressure...................................................90 3.5 Pipeline with Intermediate Injections and Deliveries ...................................93 3.6 Series Piping ................................................................................................104 3.7 Parallel Piping ..............................................................................................111 3.8 Locating Pipe Loop......................................................................................121 3.9 Hydraulic Pressure Gradient........................................................................123 3.10 Pressure Regulators and Relief Valves ........................................................126 3.11 Temperature Variation and Gas Pipeline Modeling ....................................129 3.12 Line Pack......................................................................................................132 3.13 Summary ......................................................................................................135 Problems ................................................................................................................136 References..............................................................................................................137 Chapter 4 Compressor Stations 4.1 Compressor Station Locations .....................................................................139 4.2 Hydraulic Balance........................................................................................146 4.3 Isothermal Compression ..............................................................................146 4.4 Adiabatic Compression ................................................................................148 4.5 Polytropic Compression...............................................................................151 4.6 Discharge Temperature of Compressed Gas ...............................................152 4.7 Horsepower Required...................................................................................153 4.8 Optimum Compressor Locations.................................................................157 4.9 Compressors in Series and Parallel .............................................................163 4.10 Types of Compressors—Centrifugal and Positive Displacement ..............166 4.11 Compressor Performance Curves ................................................................168 4.12 Compressor Station Piping Losses ..............................................................171 4.13 Compressor Station Schematic ....................................................................172 4.14 Summary ......................................................................................................173 Problems ................................................................................................................174 References..............................................................................................................175 Chapter 5 Pipe Loops versus Compression 5.1 Purpose of a Pipe Loop ...............................................................................177 5.2 Purpose of Compression ..............................................................................178 5.3 Increasing Pipeline Capacity .......................................................................179 5.4 Reducing Power Requirements....................................................................189 Copyright 2005 by Taylor & Francis Group, LLC 5.5 Looping in Distribution Piping....................................................................192 5.6 Summary ......................................................................................................198 Problems ................................................................................................................198 References..............................................................................................................199 Chapter 6 Pipe Analysis 6.1 Pipe Wall Thickness.....................................................................................201 6.2 Barlow’s Equation........................................................................................202 6.3 Thick-Walled Pipes ......................................................................................203 6.4 Derivation of Barlow’s Equation .................................................................205 6.5 Pipe Material and Grade ..............................................................................207 6.6 Internal Design Pressure Equation ..............................................................207 6.7 Class Location..............................................................................................209 6.8 Mainline Valves............................................................................................210 6.9 Hydrostatic Test Pressure ............................................................................211 6.10 Blowdown Calculations ...............................................................................242 6.11 Determining Pipe Tonnage ..........................................................................243 6.12 Summary ......................................................................................................246 Problems ................................................................................................................246 References..............................................................................................................247 Chapter 7 Thermal Hydraulics 7.1 Isothermal versus Thermal Hydraulics........................................................249 7.2 Temperature Variation and Gas Pipeline Modeling ....................................251 7.3 Review of Simulation Model Reports .........................................................253 7.4 Summary ......................................................................................................273 Problems ................................................................................................................274 References..............................................................................................................274 Chapter 8 Transient Analysis and Case Studies 8.1 Unsteady Flow .............................................................................................275 8.1.1 Transient Due to Mainline Valve Closure .......................................276 8.1.2 Transient Due to Compressor Shutdown.........................................277 8.2 Case Studies .................................................................................................279 8.2.1 Offshore Pipeline Case ....................................................................279 8.3 Summary ......................................................................................................296 Problems ................................................................................................................296 References..............................................................................................................297 Chapter 9 Valves and Flow Measurements 9.1 Purpose of Valves.........................................................................................299 9.2 Types of Valves ............................................................................................300 9.3 Material of Construction..............................................................................302 9.4 Codes for Design and Construction ............................................................302 9.5 Gate Valve ....................................................................................................303 Copyright 2005 by Taylor & Francis Group, LLC 9.6 Ball Valve .....................................................................................................305 9.7 Plug Valve ....................................................................................................305 9.8 Butterfly Valve .............................................................................................305 9.9 Globe Valve ..................................................................................................306 9.10 Check Valve..................................................................................................307 9.11 Pressure Control Valve.................................................................................308 9.12 Pressure Regulator .......................................................................................309 9.13 Pressure Relief Valve ...................................................................................309 9.14 Flow Measurement.......................................................................................310 9.15 Flow Meters .................................................................................................310 9.15.1 Orifice Meter ..................................................................................310 9.15.1.1 Meter Tube....................................................................313 9.15.1.2 Expansion Factor ..........................................................314 9.16 Venturi Meter ...............................................................................................321 9.17 Flow Nozzle .................................................................................................323 9.18 Summary ......................................................................................................325 Problems ................................................................................................................325 References..............................................................................................................325 Chapter 10 Pipeline Economics 10.1 Components of Cost.....................................................................................328 10.2 Capital Costs ................................................................................................330 10.2.1 Pipeline...........................................................................................330 10.2.2 Compressor Stations.......................................................................332 10.2.3 Mainline Valve Stations .................................................................333 10.2.4 Meter Stations and Regulators.......................................................333 10.2.5 SCADA and Telecommunication System......................................333 10.2.6 Environmental and Permitting .......................................................334 10.2.7 Right of Way Acquisitions.............................................................334 10.2.8 Engineering and Construction Management .................................335 10.2.9 Other Project Costs ........................................................................335 10.3 Operating Costs............................................................................................336 10.4 Determining Economic Pipe Size................................................................339 10.5 Summary ......................................................................................................353 Problems ................................................................................................................353 References..............................................................................................................354 Appendix A Units and Conversions ..................................................................355 Appendix B Physical Properties of Various Gases ...........................................359 Appendix C Pipe Properties—U.S. Customary System of Units.....................363 Appendix D GASMOD Output Report.............................................................373 Appendix E Summary of Formulas...................................................................379 Copyright 2005