Natural Gas Processing Principles and Technology - Part I

1 Printed: 26 April 2004 - [ Natural Gas Processing Principles and Technology - Part ] University of Calgary Natural Gas Processing Principles and Technology - Part I April 2004 Author: Dr. Younger, Revised and Prepared by: Dr Harald F. Thimm & Jason Sullivan Thimm Engineering Inc. 214, 3916 64th Avenue SE Calgary, Alberta T2C 2B4 Tel: (403) 265 - 0792 Web: Natural Gas Processing Principles and Technology - Part I University of Calgary April 2004: i (366) Printed: 26 April 2004 - [ Natural Gas Processing Principles and Technology - Part ] Table of Contents Table of Contents .. i List of vii List of Tables .. xii Purpose of this xiv Preface .. xiv Introduction ..1-1 Natural Gas ..1-1 Why Process Natural Gas? ..1-1 Chemical Composition of Natural Gas ..1-2 Further Discussions on Pipeline Gas Specifications ..1-6 Special specifications ..1-7 Calculations Involving Gas Composition ..1-9 By-Products from Natural General Processing Schemes.

2 1-12 References ..1-15 Reading Physical Properties of Light Hydrocarbons and Other Associated Compounds 2-1 Equations of State ..2-2 Compressibility Factors ..2-6 Liquid Densities ..2-18 Density of Cryogenic Liquids ..2-18 Thermodynamic Properties ..2-20 Outline of Correlation Methods ..2-27 Processes Using Enthalpy ..2-28 Process Using Entropy ..2-29 Heats of Combustion ..2-29 Viscosity ..2-33 Liquids ..2-33 Gases ..2-33 Thermal Conductivities ..2-36 Surface Tension ..2-36 Molecular Weights of Hydrocarbons (MW)..2-36 References ..2-39 Reading Natural Gas Processing Principles and Technology - Part I April 2004: ii (366) University of Calgary Printed: 26 April 2004 - [ Natural Gas Processing Principles and Technology - Part ] Phase Behaviour of Natural Gas 3-1 What is a Phase? .. 3-1 What are Some Phases and Their Features?.. 3-1 Why Study About Phases? .. 3-2 History .. 3-2 Single Component 3-2 Critical Points.

3 3-5 Vapour Pressure .. 3-6 Summary - Single Component .. 3-6 The Phase Rule .. 3-6 Systems of More Than One 3-7 Definitions .. 3-12 Multicomponent Systems .. 3-12 Retrograde 3-13 Typical 3-14 Oil Reservoir .. 3-14 Dry Gas 3-15 Wet Gas 3-15 Condensate Reservoir .. 3-16 Ideal 3-16 The Sulphur / H2S System .. 3-16 References .. 3-18 Reading List .. 3-18 Vapour Liquid Equilibrium Data and Computations .. 4-1 Introduction .. 4-1 Equilibrium Constants .. 4-1 Ideal Equilibrium Ratio .. 4-1 Raoult Law .. 4-2 Dalton's 4-2 Modifications of Ideal Equilibrium 4-2 Actual "K s"..4-3 Measurement of Actual "K s".. 4-4 Methods of Determining "K" .. 4-5 Convergence Pressure .. 4-5 How to Find The Convergence Pressures .. 4-7 Other "K" Data Using the Convergence Pressure Concept .. 4-10 K Data by Means of Analytic 4-10 A Comparison of the Methods of Determining "K" .. 4-16 Calculations Involving K Factors.

4 4-17 "K" Data for Special Compounds or Systems .. 4-21 References .. 4-25 Reading List .. 4-26 Water Hydrocarbon Systems .. 5-1 Natural Gas Processing Principles and Technology - Part I University of Calgary April 2004: iii (366) Printed: 26 April 2004 - [ Natural Gas Processing Principles and Technology - Part ] Why Do We Consider These Systems? ..5-1 Typical Water-Hydrocarbon Systems ..5-1 Water Content of Natural Gas ..5-3 Water Content of Liquid Hydrocarbons ..5-7 The Measuring of The Water Content ..5-7 Hydrocarbons in Hydrates ..5-7 Conditions for Hydrates to Calculation of the Possibility of Hydrates Forming ..5-10 The Prevention of More Example Problems ..5-17 References ..5-19 Reading Flow of Fluids ..6-1 What is a Fluid?..6-1 Classes of Fluids ..6-1 Other Comments ..6-2 Energy Equations ..6-4 The Drag Law ..6-4 Energy Equation ..6-4 Basic Equation for Incompressible Friction Factor.

5 6-7 Flow Pattern in Pipe ..6-9 Liquid Flow ..6-9 Gas Flow ..6-15 Adiabatic Flow ..6-16 Isothermal Flow ..6-18 Common Formula for Gas Flow ..6-20 Summary of Equations for Single Phase Gas Pipelines Using One-Step Calculation Procedure ..6-23 Line Sizing ..6-26 Gathering Pipelines ..6-26 Gas Transmission ..6-26 Steam ..6-27 Two Phase Flow ..6-27 Types of Flow ..6-28 Formulas for Various Types of Liquid Holdup ..6-41 Pressure Drop Due to Elevation Change ..6-41 Method of Flanigan5 for Two Phase ..6-41 Natural Gas Processing Principles and Technology - Part I April 2004: iv (366) University of Calgary Printed: 26 April 2004 - [ Natural Gas Processing Principles and Technology - Part ] The Flanigan 6-41 Method of Gregory, Mandhane and 6-41 Measurement of 6-47 Units of Measurement .. 6-47 Measuring 6-48 Two Phase Flow 6-50 MOVING OF 6-56 Specification of 6-56 Compressor Specifying.

6 6-58 Example Problems .. 6-58 References .. 6-62 Reading List .. 6-62 Mass 7-1 Introduction .. 7-1 What is a Mass Transfer? .. 7-1 Types of Processes Considered .. 7-1 Primary 7-1 Types of Diffusion .. 7-3 Molecular 7-3 Eddy Diffusion .. 7-4 Rate of 7-4 Mass Transfer Coefficients .. 7-9 Review of Processes Depending on Ideal Stages .. 7-13 Absorption .. 7-14 Stripping .. 7-14 Terms 7-14 Equipment .. 7-15 Tray Types .. 7-15 Tray Selection .. 7-16 Detailed Tray Diagrams .. 7-17 Packing .. 7-18 Tower Sizing - Trayed Towers .. 7-19 General .. 7-19 Diameter Determinations .. 7-19 Entrainment .. 7-19 7-19 Gas Loaded Towers .. 7-19 Liquid Loaded Towers .. 7-23 Tower Sizing Packed Columns .. 7-24 Tower Height - Distillation .. 7-25 General .. 7-25 Two Component Distillation .. 7-27 Natural Gas Processing Principles and Technology - Part I University of Calgary April 2004: v (366) Printed: 26 April 2004 - [ Natural Gas Processing Principles and Technology - Part ] McCabe Thiele7 Method of Finding Number of Ideal Stages for a Two Component System.

7 7-28 Ponchon8 Savarit9 Method for Number of Ideal Stages Use of H - X Diagram ..7-33 Analysis of a Fractionating Column ..7-38 Multicomponent Mixtures ..7-44 Efficiency ..7-50 Tower Height Absorption ..7-52 Absorption of a Single Multicomponent Absorption ..7-54 Simplified Method for Finding the Number of Trays for Absorption (Short Cut Method) 7-58 Kremser Brown Method of Finding the Number of Trays for More exact methods for finding absorption Horton & Franklin Edmister Encountered Problems ..7-59 Temperature Effects ..7-60 Changes Throughout the Tower ..7-60 Adsorption ..7-61 Physical Adsorption (van der Waal's Adsorption)..7-62 Chemical Adsorption ..7-62 Equilibrium Data ..7-62 Nature of Adsorbents ..7-63 How Adsorption Proceeds ..7-63 Sizing of Beds ..7-63 Example Problems ..7-64 References ..7-67 Reading Heat Transfer ..8-1 Conduction ..8-1 Convection ..8-2 Radiation.

8 8-2 Heat Exchange Other Liquid to Liquid Exchangers ..8-4 Air Exchangers ..8-5 Costs ..8-6 Furnaces ..8-7 Equipment Sizing ..8-7 Heat Exchangers ..8-7 Fouling Resistances ..8-14 Considerations in Fouling Resistance Typical Fouling Resistances ..8-14 Natural Gas Processing Principles and Technology - Part I April 2004: vi (366) University of Calgary Printed: 26 April 2004 - [ Natural Gas Processing Principles and Technology - Part ] 8-16 Reboilers .. 8-18 Air 8-20 Furnaces .. 8-21 Specifying 8-22 Physical Properties .. 8-23 Material of Construction .. 8-23 8-23 Mechanical Design 8-23 Performance 8-25 Process Conditions .. 8-25 Heat Transfer to Buried Pipelines .. 8-28 Example Problems .. 8-36 References .. 8-40 Reading List .. 8-40 Chemical Kinetics .. 9-1 Introduction .. 9-1 Chemical Reactions .. 9-1 Reaction 9-5 Classification of Reactions .. 9-6 The Order of a 9-6 Reactor Process Design.

9 9-9 Types of Reactors .. 9-9 Material Balance .. 9-11 Sulphur 9-13 Example Problems .. 9-15 Appendix Natural Gas Processing Principles and Technology - Part I .. 18 List of Key Terms .. 19 List of Example Problems .. 22 List of Equations .. 23 Reference of Key Equations .. 33 Natural Gas Processing Principles and Technology - Part I University of Calgary April 2004: vii (366) Printed: 26 April 2004 - [ Natural Gas Processing Principles and Technology - Part ] List of Figures Figure : Overall Gas Processing Scheme ..1-14 Figure : Actual and Pseudo Critical Points ..2-9 Figure : Pseudo Critical Temperature Correction Factor, , F ..2-14 Figure : Pseudo Critical Temperature Correction Factor, Normal Operating Range , , Figure : Generalized Compressibility Factor for Simple Fluid ..2-16 Figure : Generalized Compressibility Factor Correction for Deviation from Simple Fluid ..2-17 Figure : Density of Remainder of System Grams Per CC.

10 2-20 Figure : Enthalpy of Gases in Solution ..2-28 Figure : Natural Gas Expansion-Temp. Reduction Curve Based on .7 Sp. Gr. Gas ..2-32 Figure : Effect of Temp. on Viscosity of Molten Sulphur ..2-34 Figure : Thermal Conductivity of Normal Paraffinic Hydrocarbons ..2-35 Figure : Three Dimensional Diagram for a Single Figure : PT Diagram - Single Component ..3-4 Figure : PV Diagram - Single Component ..3-4 Figure : Schematic Representation of P-T-x Behavior of a Typical Binary System ..3-9 Figure : PT Diagram - Two Components (A & B), Different Composition ..3-10 Figure : PT Diagram - Two Components, Constant Composition ..3-10 Figure : Temperature Composition Diagram ..3-11 Figure : Vapour Liquid Composition Diagram ..3-11 Figure : Non-ideal Temperature Composition Figure : Retrograde Phenomena Figure : Retrograde Phenomena Figure : Oil Reservoir Phase Envelope ..3-14 Figure : Dry Gas Reservoir Phase Envelope.