Petroleum Refining Design and Applications Handbook, Volume 3: Mechanical Separations, Distillation, Packed Towers, Liquid-Liquid Extraction, Process Safety Incidents

Cover
Half-Title Page
Series Page
Title Page
Copyright Page
Companion Web Page
Dedication
Contents
Preface
Acknowledgments
18. Mechanical Separations
18.1 Particle Size
18.2 Preliminary Separator Selection
Guide to Dust Separator Applications
Guide to Liquid–Solid Particle Separators
18.3 Gravity Settlers
18.4 Terminal Velocity
18.5 Alternate Terminal Velocity Calculation
Pressure Drop
18.6 American Petroleum Institute’s Oil Field Separators
18.7 Liquid/Liquid, Liquid/Solid Gravity Separations, Decanters, and Sedimentation Equipment
Thickeners and Settlers
18.8 Horizontal Gravity Settlers or Decanters, Liquid/Liquid
Height of Aqueous Layer to the Interface
Optimum Vessel Diameter
18.9 Modified Method of Happel and Jordan
18.10 Decanter
Guidelines for Successful Decanters
18.11 Impingement Separators
Knitted Wire Mesh
Mesh Patterns
Capacity Determination
Fiber Bed/Pad Impingement Eliminators
18.12 Centrifugal Separators
Stationary Vane
Efficiency
Two-Phase Separators
Vessel Internals
Residence Times
Selection of Separators
Troubleshooting Gas–Liquid Separators
Gas–Liquid Separators
Horizontal Versus Vertical Separators
Sizing of Vertical and Horizontal Separators
Calculation Method for a Vertical Drum
Calculation Method for a Horizontal Drum
Liquid–Liquid Separation
Liquid Holdup and Vapor Space Disengagement
Wire Mesh Pad
Standards for Horizontal Separators
Sizing Horizontal Separators
Gas Capacity Constraint
Liquid Capacity Constraint
Seam-to-Seam Length
Slenderness Ratio
Procedure for Sizing Horizontal Separators—Half Full
Horizontal Separators Sizing Other Than Half Full
Liquid Capacity Constraint
Sizing Vertical Separators
Gas Capacity Constant
Liquid Capacity Constraint
Seam-to Seam Length
Slenderness Ratio
Procedure for Sizing Vertical Separators
A Case Study
Three-Phase Separators
Separator Selection
Sizing Parameters and Guidelines
Separation Setup
High, Very High and Low, Very Low Levels for Instrumentation and Control
Sizing Three-Phase Oil–Gas Separator
Procedure for Vertical Separator
Gas Capacity Constraint
Settling
Settling Oil From Water Phase
Retention Time Constraint
Seam-to-Seam Length
Slenderness Ratio
Procedure for Sizing Three-Phase Vertical Separators
Horizontal Separator Sizing—Half Full
Gas Capacity Constraint
Gas Capacity
Retention Time
Settling Water Droplets From Oil Phase
Separating Oil Droplets from Water Phase
Seam-to-Seam Length
Slenderness Ratio
Procedure for Sizing Three-Phase Horizontal Separators—Half-Full
Horizontal Separators Sizing Other Than Half-Full
Gas Capacity Constraint
Retention Time Constraint
Settling Equation Constraint
A Case Study (UniSim Design)
Spherical Separators
Operating Problems
Foamy Crude
Paraffin
Sand
Liquid Carryover
Gas Blowby
Emulsion
Piping Requirements
Cyclone Separators
Solid Particle Cyclone Design
Cyclone Design Procedure
The Equations
Saltation Velocity
Pressure Drop (ΔP)
Critical Particle Diameter
Cyclone Design Factors
Troubleshooting Cyclone Maloperations
Cyclone Collection Efficiency
Friction Loss ➀ to ➁
Friction Loss ➁ to ➂
Friction Loss ➂ to ➃
Friction Loss ➃ to ➄
Liquid Cyclone-Type Separator
Liquid Cyclone Design (Based on Air–Water at Atmospheric Pressure)
Liquid–Solid Cyclone (Hydrocyclones) Separators
Solid Particles in Gas/Vapor or Liquid Streams
Inertial Centrifugal Separators
Scrubbers
Cloth or Fabric Bag Separators or Filters
Specifications
Electrical/Electrostatic Precipitators
Electrostatic Precipitator Explosion: A Case Study of an Explosion in the ExxonMobil Torrance, California Refinery’s Electrostatic Precipitator (ESP) Control Air Pollution due to a Lacked Safety Instrumentation, Equipment Failure, Safe Operating Limits and Improper Safeguard as Sufficient Hazard Analysis
Process Description
Key Factors That Contributed to a Flammable Mixture Accumulating Inside of the Electrostatic Precipitator (ESP)
Key Findings Identified in the CSB Investigation
The US Chemical Safety and Hazard Investigation Board (CSB) Board Key Lessons
Conclusions
The CSB Recommendations
Nomenclature
Subscripts
Greek Symbols
References
19. Distillation
19.30 Simulation of a Fractionating Column
19. Distillation
19.1 Distillation Process Performance
19.2 Equilibrium Basic Considerations
19.3 Vapor–Liquid Equilibria
19.4 Activity Coefficients
19.5 Excess Gibbs Energy—GE
19.6 K-Value
19.7 Ideal Systems
19.8 Henry’s Law
19.8.1 Strict Henry’s Law
19.8.2 Simple Henry’s Law
19.9 K-Factor Hydrocarbon Equilibrium Charts
19.10 Non-Ideal Systems
19.11 Thermodynamic Simulation Software Programs
19.12 Vapor Pressure
Vapor Pressure Determination Using the Clausius–Clapeyron and the Antoine Equations
19.13 Azeotropic Mixtures
19.14 Bubble Point of Liquid Mixture
19.14.1 Dew Point Calculations
The Algorithm
Dew Point Calculation
19.15 Equilibrium Flash Computations
19.15.1 Fundamentals
19.15.2 Calculation of Bubble Point and Dew Point
The Algorithm
The Program
19.16 Degrees of Freedom
19.17 UniSim (Honeywell) Software
19.18 Binary System Material Balance: Constant Molal Overflow Tray to Tray
19.18.1 Conditions of Operation (Usually Fixed)
19.18.2 Flash Vaporization
19.19 Determination of Distillation Operating Pressures
19.20 Condenser Types From a Distillation Column
19.20.1 Total Condenser
19.20.2 Partial Condenser
19.21 Effect of Thermal Condition of Feed
19.22 Effect of Total Reflux, Minimum Number of Plates in a Distillation Column
19.22.1 Fenske Equation: Short-Cut Prediction of Overall Minimum Total Trays in a Column With Total Condenser
19.23 Relative Volatility α Separating Factor in a Vapor–Liquid System
19.24 Rapid Estimation of Relative Volatility
19.25 Estimation of Relative Volatilities Under 1.25 (α < 125) by Ryan
19.26 Estimation of Minimum Reflux Ratio: Infinite Plates
19.27 Calculation of Number of Theoretical Trays at Actual Reflux
19.28 Identification of “Pinch Conditions” on an x-y Diagram at High Pressure
19.29 Distillation Column Design
19.29.1 Design Method for a Plate Column
19.29.2 Continuous Fractionating Column
19.30 Simulation of a Fractionating Column
Rectifying Section
Stripping Section
Actual Operating Line
Rectifying Section Equation for Operating Line
19.31 Determination of Number of Theoretical Plates in Fractionating Columns by the Smoker Equations at Constant Relative Volatility (α = constant)
The Equations
19.31.1 Application of Smoker’s Method to a Binary Distillation Column
19.32 The Jafarey, Douglas, and McAvoy Equation: Design and Control
Summary
Overhead
Bottoms
Relative Volatility: Overhead Conditions
Thermal Condition of the Feed at 158°F
Minimum Number Tray at Total Reflux
Summary
Minimum Reflux Ratio
19.33 Number of Theoretical Trays at Actual Reflux
Tray Efficiency
Actual Trays at Actual Reflux
Types of Tray
19.34 Estimating Tray Efficiency in a Distillation Column
19.35 Steam Distillation
19.35.1 Steam Distillation-Continuous Flash, Multicomponent, or Binary Mixture
19.35.2 Steam Distillation-Continuous Differential, Multicomponent, or Binary Mixture
19.35.3 Steam Distillation-Continuous Flash, Two Liquid Phases, Multicomponent, and Binary Mixture
19.35.4 Open Live Steam Distillation—With Fractionation Trays, Binary Mixture
19.36 Distillation with Heat Balance of Component Mixture
19.36.1 Unequal Molal Overflow
19.36.2 Ponchon–Savarit Method-Binary Mixtures
19.37 Multicomponent Distillation
Key Components
19.37.1 Minimum Reflux Ratio-Infinite Plates
19.37.2 The Fenske’s Method for Total Reflux [142]
19.37.3 The Gilliland Method for Number of Equilibrium Stages [90]
19.37.4 Underwood’s Method [88, 144]
19.36.5 Equations for Describing Gilliland’s Graph
19.37.6 Operating Reflux Ratio, R
19.37.7 Feed Tray Location
19.37.8 Kirkbride’s Feed Plate Location [153]
19.37.9 Algebraic Plate-to-Plate Method
19.37.10 Erbar–Maddox Method [158]
19.37.11 Underwood Algebraic Method: Adjacent Key Systems [144]
19.37.12 Underwood Algebraic Method: Adjacent Key Systems; Variable α
19.37.13 Underwood Algebraic Method: Split Key Systems: Constant Volatility [144]
19.37.14 Minimum Reflux Colburn Method: Pinch Temperatures [161]
19.38 Scheibel–Montross Empirical: Adjacent Key Systems: Constant or Variable Volatility [162]
19.39 Minimum Number of Trays: Total Reflux−Constant Volatility
19.39.1 Theoretical Number of Trays at Operating Reflux of a Multicomponent Mixture
19.39.2 Actual Number of Trays
19.39.3 Estimation of Multicomponent Recoveries
19.39.4 Component Recovery Nomograph
19.39.5 Shortcut Methods: Reflux Ratio and Stages
19.40 Smith–Brinkley (SB) Method
Application
Minimum Reflux Ratio and Minimum Number of Stages by Simulation
Optimization of the Feed Stage by Simulation
19.41 Retrofit Design of Distillation Columns
19.42 Tray-by-Tray for Multicomponent Mixtures
Procedure
A. Rectifying Section
B. Stripping Section
19.43 Tray-by-Tray Calculation of a Multicomponent Mixture Using a Digital Computer
Determine Overhead Temperature
Determine Bottoms Temperature (Bubble Point)
19.44 Thermal Condition of Feed
19.45 Minimum Reflux-Underwood Method, Determination of αAvg for Multicomponent Mixture
Operating Reflux and Theoretical Trays—Gilliland Plot
Tray-by-Tray Calculation—Ackers and Wade Method
Stripping Section
Tray Efficiency
19.46 Heat Balance-Adjacent Key Systems with Sharp Separations, Constant Molal Overflow
Total Condenser Duty
Reboiler Duty
19.47 Stripping Volatile Organic Chemicals (VOC) from Water with Air
19.48 Rigorous Plate-to-Plate Calculation (Sorel Method)
19.49 Multiple Feeds and Side Streams for a Binary Mixture
Side Stream Columns
19.50 Chou and Yaws Method
19.51 Optimum Reflux Ratio and Optimum Number of Trays Calculations
Correlations
Procedure
Input Data
Flow Regime in Trays
19.52 Tower Sizing for Valve Trays
The Equations
19.52.1 Diameter of Sieve/Valve Trays (F Factor)
19.52.2 Diameter of Sieve/Valve Trays (Lieberman)
Tray Geometry Sizing
19.53 Troubleshooting, Predictive Maintenance, and Controls for Distillation Columns
Fractionating Tray Stability Diagrams
Areas of Unacceptable Operation
Spray Entrainment Flooding
Froth Entrainment Flooding
Downcomer Backup Flooding
Downcomer Choke Flooding
Foaming
Flooding
Entrainment
Weeping/Dumping
Fractionation Problem Solving Considerations
19.53.1 Common Problems in Distillation Columns [225]
Typical Pressure Drops (Approximate)
Trays
Pressure Survey
Verify the Column’s Operations
A Case Study
19.54 Distillation Sequencing with Columns Having More than Two Products
19.54.1 Th ermally Coupled Distillation Sequence
Advantages and Disadvantages to Divided Wall Columns
19.54.2 Practical Constraints in Sequencing Options
19.54.3 Choice of Sequence for Distillation Columns
19.55 Heat Integration of Distillation Columns
Heat Integration in a Crude Distillation Unit
Column Overhead Heat Integration
Integrated Atmospheric and Vacuum Distillation Units
19.56 Capital Cost Considerations for Distillation Columns
19.57 The Pinch Design Approach to Inventing a Network
19.58 Appropriate Placement and Integration of Distillation Columns
19.59 Heat Integration of Distillation Columns: Summary
Maximization of Crude Preheat
19.60 Common Installation Errors in Distillation Columns
Calculation of Nozzle Size [225]
Crude Column Simulation and Design
Tray Efficiencies and System Factors to be Considered for Design
Advanced Distillation Technologies
Case Study 1
Case Study 2
Case Study 3
Nomenclature: Distillation Process Performance
Greek Symbols
Subscripts
References
Bibliography
20. Packed Towers and Liquid–Liquid Extraction
Packed Towers
20.1 Shell
20.2 Random Packing
20.3 Packing Supports
20.4 Liquid Distribution
20.5 Packing Installation
Dumped
20.5.1 Packing Selection and Performance
20.6 Contacting Efficiency, Expressed as Kga, HTU, HETP
20.7 Packing Size
20.8 Pressure Drop
20.9 Materials of Construction
20.10 Particle versus Compact Preformed Structured Packings
20.10.1 Fouling of Packing
20.11 Minimum Liquid Wetting Rates
20.12 Loading Point−Loading Region
20.13 Flooding Point
20.14 Foaming Liquid Systems
20.15 Surface Tension Effects
20.16 Packing Factors
20.17 Recommended Design Capacity and Pressure Drop
20.18 Pressure Drop Design Criteria and Guide: Random Packings Only
20.19 Effects of Physical Properties
20.20 Performance Comparisons
20.20.1 Prediction of Maximum Operating Capacity (MOC)
20.21 Capacity Basis for Design
20.21.1 Flooding
20.21.2 Operating and Design Conditions
20.22 Proprietary Random Packing Design Guides
Norton Intalox® Metal Tower Packing (IMTP®)
Capacity Correlation
20.22.1 Packing Efficiency/Performance for IMTP Packing
Minimum Reflux
Theoretical Plates vs. Reflux
Nutter Ring
Capacity Correlation
20.22.2 Dumped Packing: Gas–Liquid System Below Loading
20.22.3 Dumped Packing: Loading and Flooding Regions, General Design Correlations
20.22.4 Dumped Packing: Pressure Drop at Flooding
20.25.5 Dumped Packing: Pressure Drop Below and at Flood Point, Liquid Continuous Range
20.22.6 Pressure Drop Across Packing Supports and Redistribution Plates
20.23 Liquid Hold-Up
20.23.1 Correction Factors for Liquids Other Than Water
20.24 Packing Wetted Area
20.25 Effective Interfacial Area
20.26 Entrainment from Packing Surface
Entrainment
Weights
20.27 Structured Packing
Preliminary Sizing for ACS Industries Series Woven X/S Knitted Wire Mesh Structured Packing
HETP for ACS Series X-200 Structured Packing
Pressure Drop (Estimated)
Koch Kulzer Structured Packing [66]
Column Sizing for Koch Sulzer Packing
Top Section
Nomenclature
Koch Flexipac® Structured Packing
Intalox High-Performance Metal Structural Packing
Gempack® Structured Packing; Glitsch, Inc
Grid Packing: Nutter Engineering
Koch Flexigrid® Packing: Koch Engineering Co.
Flexigrid® Style 2 High Capacity
Glitsch-GridTM [122]
20.28 Structured Packing: Technical Performance Features
Flooding
Pressure Drop
20.28.1 Guidelines for Structured Packings
20.28.2 Structured Packing Scale-Up
20.29 New Generalized Pressure Drop Correlation Charts
20.30 Mass and Heat Transfer in Packed Tower
20.31 Number of Transfer Units, NOG, NOL
For Concentrated Solutions and More General Application
20.32 Gas and Liquid-Phase Coefficients, kG and kL
20.33 Height of a Transfer Unit, HOG, HOL, HTU
Height of Overall Transfer Unit
Height of Individual Transfer Unit
Estimation of Height of Liquid Film Transfer Units
Estimation of Height of Gas Film Transfer Units
Estimation of Diffusion Coefficients to Gases
20.34 Distillation in Packed Towers
20.34.1 Height Equivalent to a Theoretical Plate (HETP)
20.34.2 HETP Guide Lines
20.34.3 Transfer Unit
20.35 Liquid–Liquid Extraction
20.35.1 BTX Recovery by Solvent Extraction
20.36 Process Parameters
20.36.1 Procedure
20.37 Solvents Selection for the Extraction Unit
Viscosity Index Improvement
20.38 Phenol Extraction Process of Lubes
20.38.1 Process Description
20.39 Furfural Extraction Process
20.40 Dispersed-Phase Droplet Size
Viscosity
20.40.1 Surface Wetting
20.40.2 Axial Mixing
Extractor Flow Patterns
20.40.3 Flooding
20.41 Theory
20.42 Nernst’s Distribution Law
20.43 Tie Lines
20.44 Phase Diagrams
20.45 Countercurrent Extractors
20.45.1 Kremser Equation
20.46 Extraction Equipment
Mixer-Settler
Advantages
Disadvantages
Columns
Rotating Disc Contactor
Advantages
Disadvantages
Case Study 2
Solution
References
Glossary of Petroleum and Petrochemical Technical Terminologies
Appendix D
Appendix F: Equilibrium K-Values
About the Author
Index
Also of Interest