Fluid Separation
0 INTRODUCTION/PURPOSE
1 SCOPE
2 FIELD OF APPLICATION
3 DEFINITIONS
4 A SEPARATION LOGIC TREE
5 METHODS OF DISTILLATION
5.1 Fractional Distillation
5.2 Azeotropic Distillation
5.3 Extractive Distillation
6 LIQUID-LIQUID EXTRACTION
7 OTHER COMMERCIAL METHODS OF SEPARATION
7.1 Adsorption
7.2 Fractional Crystallization
7.3 Ion Exchange
7.4 Membrane Processes
7.4.1 Ultrafiltration
7.4.2 Reverse Osmosis
7.4.3 Pervaporation
7.4.4 Liquid Membranes
7.4.5 Gas Permeation
7.4.6 Dialysis
7.4.7 Electrodialysis
7.5 Supercritical Fluid Extraction
7.6 Dissociation Extraction
7.7 Foam Fractionation
7.8 Clathration
7.9 Chromatography
8. OTHER METHODS OF SEPARATION
8.1 Precipitation
8.2 Paper Chromatography
8.3 Ligand Specific Chromatography
8.4 Electrophoresis
8.5 Isoelectric Focusing
8.6 Thermal Diffusion
8.7 Sedimentation Ultracentrifugation
8.8 Isopycnic Ultracentrifugation
8.9 Molecular Distillation
8.10 Gel Filtration
APPENDICES
A AT A GLANCE CHART BASED ON FENSKE, UNDERWOOD
B A GENERALIZED y - x DIAGRAM
C TEMPERATURE - COMPOSITION DIAGRAMS FOR
AZEOTROPIC MIXTURES
D A TYPICAL y - x DIAGRAM FOR EXTRACTIVE DISTILLATION (SOLVENT FREE BASIS)
E RAPID ESTIMATION OF LIQUID-LIQUID EXTRACTION REQUIREMENTS
F LIQUID - LIQUID EXTRACTION - THE USE OF EXTRACT REFLUX
G SELECTIVITIES REQUIRED FOR EQUAL PLANT COSTS
FIGURE
1 SEPARATION LOGIC TREE
1) GBHE has extensive experience designing and evaluating methane steam reformer tubes and can perform detailed simulations and modeling to optimize reformer performance during retube evaluations.
2) The methodology involves understanding current operations, simulating the existing reformer, selecting improved tube materials and catalysts, and modeling stress levels and temperatures to determine maximum operating conditions.
3) Case studies demonstrate how optimizing tubes and catalyst can increase production by 3-15% while reducing pressure drop, temperatures, and methane slip.
Catalytic Reforming Process is one of the most important processes in the petroleum and petrochemical industries which produce high octane number gasoline.
Estimation of Pressure Drop in Pipe Systems
0 INTRODUCTION/PURPOSE
1 SCOPE
2 FIELD OF APPLICATION
3 DEFINITIONS
3.1 units
4 SOURCES OF DATA
5 BASIC CONCEPTS
5.1 Equation for Pressure Change in a Flowing
Fluid
5.2 Static and Stagnation Pressures
5.3 Sonic Flow
6 INCOMPRESSIBLE FLOW IN PIPES OF CONSTANT
CROSS-SECTION
6.1 Straight Circular Pipes
6.2 Ducts of Non-circular Cross-section
6.3 Coils
6.4 General Equation for Incompressible Flow
in Pipes of Constant Cross-section
7 COMPRESSIBLE FLOW IN PIPES OF CONSTANT
CROSS-SECTION
7.1 Isothermal Flow
7.2 Adiabatic Flow
7.3 Estimation of Pressure Drop for Adiabatic
Flow in Pipes of Constant Cross-section
7.4 Ratio of Isothermal to Adiabatic Pressure Drop
8 FLOW IN PIPE FITTINGS
8.1 Incompressible Flow
8.2 Compressible Flow
9 FLOW IN BENDS
9.1 Incompressible Flow in Bends
9.2 Compressible Flow in Bends
10 CHANGES IN CROSS-SECTIONAL AREA
9.1 Incompressible Flow
9.2 Compressible Flow
11 ORIFICES, NOZZLES AND VENTURIS
11.1 Incompressible Flow through an Orifice
11.2 Compressible Flow through an Orifice or Nozzle
11.3 Venturi Choke Tubes
12 VALVES
12.1 General
12.2 Incompressible Flow in Valves
12.2 Compressible Flow in Valves
13 COMBINING AND DIVIDING FLOW
9.1 Incompressible Flow
9.2 Compressible Flow
14 COMPUTER PROGRAMS FOR FLUID FLOW
15 NOMENCLATURE
16 REFERENCES
APPENDICES
A BASIC THERMODYNAMICS
B COMPRESSIBLE FLOW THROUGH ORIFICES
C THE ‘TWO-K’ METHOD FOR FITTING PRESSURE LOSS
Thermal conversion processes include thermal cracking, visbreaking, coking, and coke calcination. Thermal cracking involves cracking large hydrocarbon molecules into smaller ones at high temperatures. Visbreaking is a mild thermal cracking process used to reduce the viscosity of residues and produce fuel oil, naphtha, and gas oil. Coking involves heating residues to very high temperatures to produce coke and lighter hydrocarbon products.
This document discusses crude oil processing and the production of hydrocarbon intermediates. It describes how crude oil is distilled through atmospheric and vacuum distillation to produce simple fractions like naphtha, gas oil, and catalytic cracker gases. These refinery products undergo further processing through thermal cracking, catalytic cracking, and steam reforming to produce olefins, diolefins, and aromatics. Key processes mentioned include thermal cracking (steam cracking) to produce ethylene and catalytic reforming to produce BTX aromatics. Delayed coking is also summarized as a thermal cracking process used to upgrade heavy residues into lighter fractions.
This document discusses catalytic reforming and hydrocracking processes. It provides details on:
- Catalytic reforming converts low octane naphtha into high octane reformates through reactions like dehydrogenation and dehydrocyclization.
- Hydrocracking breaks down heavier hydrocarbon molecules into simpler molecules like gasoline and kerosene using hydrogen and catalysts at high pressures.
- Both processes upgrade petroleum fractions through chemical reactions like cracking, isomerization and hydrogenation to produce more valuable products like gasoline and jet fuel.
1) GBHE has extensive experience designing and evaluating methane steam reformer tubes and can perform detailed simulations and modeling to optimize reformer performance during retube evaluations.
2) The methodology involves understanding current operations, simulating the existing reformer, selecting improved tube materials and catalysts, and modeling stress levels and temperatures to determine maximum operating conditions.
3) Case studies demonstrate how optimizing tubes and catalyst can increase production by 3-15% while reducing pressure drop, temperatures, and methane slip.
Catalytic Reforming Process is one of the most important processes in the petroleum and petrochemical industries which produce high octane number gasoline.
Estimation of Pressure Drop in Pipe Systems
0 INTRODUCTION/PURPOSE
1 SCOPE
2 FIELD OF APPLICATION
3 DEFINITIONS
3.1 units
4 SOURCES OF DATA
5 BASIC CONCEPTS
5.1 Equation for Pressure Change in a Flowing
Fluid
5.2 Static and Stagnation Pressures
5.3 Sonic Flow
6 INCOMPRESSIBLE FLOW IN PIPES OF CONSTANT
CROSS-SECTION
6.1 Straight Circular Pipes
6.2 Ducts of Non-circular Cross-section
6.3 Coils
6.4 General Equation for Incompressible Flow
in Pipes of Constant Cross-section
7 COMPRESSIBLE FLOW IN PIPES OF CONSTANT
CROSS-SECTION
7.1 Isothermal Flow
7.2 Adiabatic Flow
7.3 Estimation of Pressure Drop for Adiabatic
Flow in Pipes of Constant Cross-section
7.4 Ratio of Isothermal to Adiabatic Pressure Drop
8 FLOW IN PIPE FITTINGS
8.1 Incompressible Flow
8.2 Compressible Flow
9 FLOW IN BENDS
9.1 Incompressible Flow in Bends
9.2 Compressible Flow in Bends
10 CHANGES IN CROSS-SECTIONAL AREA
9.1 Incompressible Flow
9.2 Compressible Flow
11 ORIFICES, NOZZLES AND VENTURIS
11.1 Incompressible Flow through an Orifice
11.2 Compressible Flow through an Orifice or Nozzle
11.3 Venturi Choke Tubes
12 VALVES
12.1 General
12.2 Incompressible Flow in Valves
12.2 Compressible Flow in Valves
13 COMBINING AND DIVIDING FLOW
9.1 Incompressible Flow
9.2 Compressible Flow
14 COMPUTER PROGRAMS FOR FLUID FLOW
15 NOMENCLATURE
16 REFERENCES
APPENDICES
A BASIC THERMODYNAMICS
B COMPRESSIBLE FLOW THROUGH ORIFICES
C THE ‘TWO-K’ METHOD FOR FITTING PRESSURE LOSS
Thermal conversion processes include thermal cracking, visbreaking, coking, and coke calcination. Thermal cracking involves cracking large hydrocarbon molecules into smaller ones at high temperatures. Visbreaking is a mild thermal cracking process used to reduce the viscosity of residues and produce fuel oil, naphtha, and gas oil. Coking involves heating residues to very high temperatures to produce coke and lighter hydrocarbon products.
This document discusses crude oil processing and the production of hydrocarbon intermediates. It describes how crude oil is distilled through atmospheric and vacuum distillation to produce simple fractions like naphtha, gas oil, and catalytic cracker gases. These refinery products undergo further processing through thermal cracking, catalytic cracking, and steam reforming to produce olefins, diolefins, and aromatics. Key processes mentioned include thermal cracking (steam cracking) to produce ethylene and catalytic reforming to produce BTX aromatics. Delayed coking is also summarized as a thermal cracking process used to upgrade heavy residues into lighter fractions.
This document discusses catalytic reforming and hydrocracking processes. It provides details on:
- Catalytic reforming converts low octane naphtha into high octane reformates through reactions like dehydrogenation and dehydrocyclization.
- Hydrocracking breaks down heavier hydrocarbon molecules into simpler molecules like gasoline and kerosene using hydrogen and catalysts at high pressures.
- Both processes upgrade petroleum fractions through chemical reactions like cracking, isomerization and hydrogenation to produce more valuable products like gasoline and jet fuel.
This document provides an overview of distillation as a separation process. It defines distillation and describes its applications. The key principles of distillation discussed include how separation depends on differences in boiling points. Concepts such as relative volatility and vapor-liquid equilibrium diagrams are introduced to explain how distillation utilizes differences in vapor pressure and boiling points. The document also discusses how pressure and temperature can impact equilibrium diagrams and the distillation process.
An Overview to the most common Industrial Mass Transfer Operations & Process Separation Technologies
Course Description
In this course we will cover the most basic processes involved in Mass Transfer Operations. This is an overview of what type of processes, methods and units are used in the industry. This is mostly an introductory course which will allow you to learn, understand and know the approach towards separation processes involving mass transfer phenomena.
It is an excellent course before any Mass Transfer Process or Unit Operation Course such as Distillations, Extractions, Leaching, Membranes, Absorption, etc...
This course is extremely recommended if you will continue with the following:
Flash Distillation, Simple Distillation, Batch Distillation
Gas Absorption, Desorption & Stripping
Binary Distillation, Fractional Distillation
Scrubbers, Gas Treating
Sprayers / Spray Towers
Bubble Columns / Sparged Vessels
Agitation Vessels
Packed Towers, Tray Towers
Membranes
Liquid Extraction
Dryers / Humidifiers
Adsorbers
Evaporators/Sublimators
Crystallizers
Centrifugations
And many other Separation Technology!
At the end of the Course:
You will be able to understand the mass transfer operations concepts. You will be able to identify Mass Transfer Unit Operations. You will be also able to ensure the type of method of separation technology used.
You will be able to apply this theory in further Unit Operations.
Theory-Based Course
This is a very theoretical course, some calculations and exercises are present, but overall, expect mostly theoretical concepts.
Processing of petroleum types of refluxKarnav Rana
PROCESSING OF PETROLEUM :TYPES OF REFLUX
arrangements of distillation towers
Pump back reflux and pump around reflux
Side stripping columns
process refining & petrochemicals
Reactor and Catalyst Design
0 INTRODUCTION/PURPOSE
1 SCOPE
2 FIELD OF APPLICATION
3 DEFINITIONS
4 CATALYST DESIGN
4.1 Equivalent Pellet Diameter
4.2 Voidage
4.3 Pellet Density
5 REACTOR DESIGN
6 CATALYST SUPPORT
6.1 Choice of Support
TABLES
1 CATALYST SUPPORT SHAPES
2 SECONDARY REFORMER SPREADSHEET
FIGURES
1 GRAPH OF EFFECTIVENESS v THIELE MODULUS
2 VARIATION OF COSTS WITH CATALYST SIZE
3 VARIATION OF COSTS WITH CATALYST BED VOIDAGE
4 VARIATION OF COSTS WITH VESSEL DIAMETER
1. Distillation is the first step in refining crude oil, where it is heated and separated into fractions based on boiling points in a fractionation column.
2. Before distillation, crude oil undergoes desalting to remove water and salts, and preheating through heat exchangers. It is then sent to a furnace and pre-flash vessel to further vaporize components.
3. Fractions are drawn off from different parts of the fractionation column for further processing. Lighter fractions condense higher in the column, while heavier fractions condense lower down.
Design and Simulation of Continuous Distillation ColumnsGerard B. Hawkins
Design and Simulation of Continuous Distillation Columns
0 INTRODUCTION/PURPOSE
1 SCOPE
2 FIELD OF APPLICATION
3 DEFINITIONS
4 FRACTIONAL DISTILLATION
5 ROUGH METHOD OF COLUMN DESIGN
5.1 Sharp Separations
5.2 Sloppy Separations
6 DETAIL DESIGN USING THE CHEMCAD DISTILLATION PROGRAM
6.1 Sharp Separations
6.2 Sloppy Separations
7 COMPLEX COLUMNS
7.1 Multiple Feeds
7.2 Sidestream Take-Offs
8 DESIGN USING A LABORATORY COLUMN
SIMULATION
9 DESIGN USING ACTUAL PLANT DATA
9.1 Uprating or Debottlenecking Exercises
10 REFERENCES
APPENDICES
A WORKED EXAMPLE
B SLOPPY SEPARATIONS
C SIMULATION USING PLANT DATA : CASE HISTORIES
TABLES
Absorption & indusrial absorber,Gas Absorption,Equipments,Absorption in chemical Reaction,Absorption in Packed Tower,Absorption for counter current,Choice of Solvent,Continuous Contact Equipment,Height Equivalent to Theoretical Plate,HETP
This document discusses secondary reforming in ammonia and hydrogen/syngas production. It explains that ammonia plants commonly use a secondary reformer fired with air, as the nitrogen from air is useful for ammonia synthesis. However, hydrogen/syngas plants less commonly use secondary reforming because nitrogen cannot be tolerated in the process and an air separation unit may not be available or affordable to provide oxygen. The document outlines the key components of secondary reformers - the burner design, mixing volume, and catalyst - which must all be optimized to improve performance.
This document contains a FAQ on chemical reaction engineering. It provides answers to 19 questions covering topics such as the rate of reaction, types of reactors, orders of reaction, catalysts, feasibility of reactions based on Gibbs free energy, and models used to represent flow in reactors. Key differences between CSTR and PFR reactors are also summarized.
Distillation is a process that separates liquid mixtures into individual fractions based on differences in boiling points. It works by heating the mixture to vaporize components with lower boiling points. There are two main types of distillation columns - batch columns which process feed intermittently, and continuous columns which process a steady stream of feed. Distillation columns contain internals like trays or packings to enhance separation, a reboiler for vaporization, a condenser to cool vapors, and a reflux drum to collect condensed liquids and provide reflux. Separation occurs due to differences in vapor pressure and relative volatility between components in the mixture.
Use and Applications of Membranes
0 INTRODUCTION/PURPOSE
1 SCOPE
2 FIELD OF APPLICATION
3 DEFINITIONS
4 GENERAL
4.1 What is a Membrane Process?
4.2 What does a Membrane look like?
4.3 Why use Membranes?
4.4 Membrane Types and Polymers Used
5 REVERSE OSMOSIS
5.1 Principles of Reverse Osmosis
5.2 Limitations
5.3 Performance
5.4 Costs
5.5 Worked Example
5.6 Applications
6 MICROFILTRATION AND ULTRAFILTRATION
6.1 Microfiltration
6.2 Ultrafiltration
7 PERVAPORATION
7.1 Classes of Application
7.2 Characteristics
7.3 Costs
7.4 Example - Lurgi Design
7.5 Application - Stripping Organics from Water
8 GAS SEPARATION AND VAPOR PERMEATION
8.1 Gas Separation
8.2 Vapor Permeation
9 LESS COMMON MEMBRANE PROCESSES
9.1 Dialysis
9.2 Electrodialysis
9.3 Electrolysis
9.4 Salt Splitting
10 BIBLIOGRAPHY
TABLES
1 UTILITY CONSUMPTION AND COST COMPARISON
COURSE LINK:
https://www.chemicalengineeringguy.com/courses/gas-absorption-stripping/
Introduction:
Gas Absorption is one of the very first Mass Transfer Unit Operations studied in early process engineering. It is very important in several Separation Processes, as it is used extensively in the Chemical industry.
Understanding the concept behind Gas-Gas and Gas-Liquid mass transfer interaction will allow you to understand and model Absorbers, Strippers, Scrubbers, Washers, Bubblers, etc…
We will cover:
- REVIEW: Of Mass Transfer Basics required
- GAS-LIQUID interaction in the molecular level, the two-film theory
- ABSORPTION Theory
- Application of Absorption in the Industry
- Counter-current & Co-current Operation
- Several equipment to carry Gas-Liquid Operations
- Bubble, Spray, Packed and Tray Column equipments
- Solvent Selection
- Design & Operation of Packed Towers
- Pressure drop due to packings
- Solvent Selection
- Design & Operation of Tray Columns
- Single Component Absorption
- Single Component Stripping/Desorption
- Diluted and Concentrated Absorption
- Basics: Multicomponent Absorption
- Software Simulation for Absorption/Stripping Operations (ASPEN PLUS/HYSYS)
----
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More likes, sharings, suscribers: MORE VIDEOS!
-----
CONTACT ME
Chemical.Engineering.Guy@Gmail.com
www.ChemicalEngineeringGuy.com
http://facebook.com/Chemical.Engineering.Guy
You speak spanish? Visit my spanish channel -www.youtube.com/ChemEngIQA
The document provides an overview of inplant training at MRPL, including:
- MRPL is a subsidiary of ONGC located in Mangalore, Karnataka.
- The refinery's units include a crude distillation unit, vacuum distillation unit, hydrocracker unit, hydrogen unit, and gas oil hydrodesulfurization unit.
- Each unit is described briefly, outlining its key processes and products. The presentation aims to educate trainees on MRPL's refinery operations and configuration.
After crude oil is desalted and dehydrated, it is separated into fractions through distillation. However, the distilled fractions cannot be used directly and require further processing due to differences between crude oil properties and market needs. The complexity of refining processes is also due to environmental regulations that require cleaner products. Distillation involves heating crude oil to separate it based on boiling points, but the distilled fractions need additional conversion processes before they can be used or sold.
This document discusses the classification and selection of chemical reactors. It outlines the basic types of reactors including batch, continuous stirred-tank (CSTR), and plug flow reactors (PFR). Selection of reactors depends on factors such as the process type (batch, continuous, catalytic), phase (gas, liquid, solid), and required mass and heat transfer rates. For example, batch reactors are used for small batch production while CSTRs are common for liquid reactions requiring mixing. PFRs provide higher efficiency and are used when significant heat transfer is needed. Selection also considers whether the reaction involves single or multiple steps.
Interpretation and Correlation of Viscometric Data
0 INTRODUCTION/PURPOSE
1 SCOPE
2 FIELD OF APPLICATION
3 DEFINITIONS
4 NON-NEWTONIAN FLUID BEHAVIOR
4.1 Introduction
4.2 Classification of Non-Newtonian Fluids
4.3 Caution
5 VISCOMETER MEASUREMENTS FOR
TIME-INDEPENDENT FLUIDS
5.1 Concentric Cylinder Viscometers
5.2 Cone and Plate Viscometers
5.3 Parallel Plate Viscometer
5.4 Tube or Capillary Viscometer
5.5 Checks for Consistency of Data and Interpretation
5.6 Estimate of Process Shear Rate
6 MODEL FITTING TO FLOW CURVES
6.1 Power Law
6.2 Bingham Plastic
6.3 Direct use of Numerical Data
6.4 Rheological Models Involving Temperature Dependence
7 CHARACTERIZATION OF TIME-DEPENDENT LIQUIDS
7.1 Sample Loading
7.2 Tests at Constant Shear Rate
7.3 Dynamic Response Measurement
7.4 Changes in Shear Rate
7.4 Concluding Remarks
8 TECHNIQUES FOR CHARACTERIZATION OF
VISCOELASTIC LIQUIDS
8.1 Stress Relaxation
8.2 Oscillatory Shear Measurements
8.3 Normal Force Measurement
8.4 Elongational Viscosity Measurement
9 NOMENCLATURE
10 BIBLIOGRAPHY
APPENDICES
A EQUATIONS FOR VISCOMETERS
A.1 EQUATIONS FOR CONCENTRIC CYLINDER
VISCOMETERS
A.2 EQUATIONS FOR CONE AND PLATE VISCOMETERS
A.3 EQUATIONS FOR PARALLEL PLATE VISCOMETER
A.4 EQUATIONS FOR TUBE OR CAPILLARY VISCOMETER
Gas Solid Mixing
0 INTRODUCTION/PURPOSE
1 SCOPE
2 FIELD OF APPLICATION
3 DEFINITIONS
4 GAS-SOLID FLUIDIZED BED
5 MIXING IN FLUIDIZED BEDS
5.1 Group A Powders
5.2 Group B Powders
5.3 Group C Powders
5.4 Group D Powders
6 MECHANISMS OF MIXING AND SEGREGATION
6.1 Particle Segregation
6.2 Rate of Mixing
6.3 Solids Circulation
7 GRID DESIGN
7.1 Choice of Configuration
8 PLENUM CHAMBER DESIGN
9 SPOUTED BED
10 NOMENCLATURE
11 BIBLIOGRAPHY
FIGURES
1 POWDER CLASSIFICATION DIAGRAM FOR
FLUIDIZATION BY AIR
2 DIAGRAMMATIC REPRESENTATION OF MIXING BY A SINGLE RISING BUBBLE IN A BED OF SMALL
PARTICLES
3 SEGREGATION PATTERNS WITH 'PRACTICAL'
MATERIALS
4 SPOUTED BED – DIAGRAMMATIC
This document provides an overview of distillation as a separation process. It defines distillation and describes its applications. The key principles of distillation discussed include how separation depends on differences in boiling points. Concepts such as relative volatility and vapor-liquid equilibrium diagrams are introduced to explain how distillation utilizes differences in vapor pressure and boiling points. The document also discusses how pressure and temperature can impact equilibrium diagrams and the distillation process.
An Overview to the most common Industrial Mass Transfer Operations & Process Separation Technologies
Course Description
In this course we will cover the most basic processes involved in Mass Transfer Operations. This is an overview of what type of processes, methods and units are used in the industry. This is mostly an introductory course which will allow you to learn, understand and know the approach towards separation processes involving mass transfer phenomena.
It is an excellent course before any Mass Transfer Process or Unit Operation Course such as Distillations, Extractions, Leaching, Membranes, Absorption, etc...
This course is extremely recommended if you will continue with the following:
Flash Distillation, Simple Distillation, Batch Distillation
Gas Absorption, Desorption & Stripping
Binary Distillation, Fractional Distillation
Scrubbers, Gas Treating
Sprayers / Spray Towers
Bubble Columns / Sparged Vessels
Agitation Vessels
Packed Towers, Tray Towers
Membranes
Liquid Extraction
Dryers / Humidifiers
Adsorbers
Evaporators/Sublimators
Crystallizers
Centrifugations
And many other Separation Technology!
At the end of the Course:
You will be able to understand the mass transfer operations concepts. You will be able to identify Mass Transfer Unit Operations. You will be also able to ensure the type of method of separation technology used.
You will be able to apply this theory in further Unit Operations.
Theory-Based Course
This is a very theoretical course, some calculations and exercises are present, but overall, expect mostly theoretical concepts.
Processing of petroleum types of refluxKarnav Rana
PROCESSING OF PETROLEUM :TYPES OF REFLUX
arrangements of distillation towers
Pump back reflux and pump around reflux
Side stripping columns
process refining & petrochemicals
Reactor and Catalyst Design
0 INTRODUCTION/PURPOSE
1 SCOPE
2 FIELD OF APPLICATION
3 DEFINITIONS
4 CATALYST DESIGN
4.1 Equivalent Pellet Diameter
4.2 Voidage
4.3 Pellet Density
5 REACTOR DESIGN
6 CATALYST SUPPORT
6.1 Choice of Support
TABLES
1 CATALYST SUPPORT SHAPES
2 SECONDARY REFORMER SPREADSHEET
FIGURES
1 GRAPH OF EFFECTIVENESS v THIELE MODULUS
2 VARIATION OF COSTS WITH CATALYST SIZE
3 VARIATION OF COSTS WITH CATALYST BED VOIDAGE
4 VARIATION OF COSTS WITH VESSEL DIAMETER
1. Distillation is the first step in refining crude oil, where it is heated and separated into fractions based on boiling points in a fractionation column.
2. Before distillation, crude oil undergoes desalting to remove water and salts, and preheating through heat exchangers. It is then sent to a furnace and pre-flash vessel to further vaporize components.
3. Fractions are drawn off from different parts of the fractionation column for further processing. Lighter fractions condense higher in the column, while heavier fractions condense lower down.
Design and Simulation of Continuous Distillation ColumnsGerard B. Hawkins
Design and Simulation of Continuous Distillation Columns
0 INTRODUCTION/PURPOSE
1 SCOPE
2 FIELD OF APPLICATION
3 DEFINITIONS
4 FRACTIONAL DISTILLATION
5 ROUGH METHOD OF COLUMN DESIGN
5.1 Sharp Separations
5.2 Sloppy Separations
6 DETAIL DESIGN USING THE CHEMCAD DISTILLATION PROGRAM
6.1 Sharp Separations
6.2 Sloppy Separations
7 COMPLEX COLUMNS
7.1 Multiple Feeds
7.2 Sidestream Take-Offs
8 DESIGN USING A LABORATORY COLUMN
SIMULATION
9 DESIGN USING ACTUAL PLANT DATA
9.1 Uprating or Debottlenecking Exercises
10 REFERENCES
APPENDICES
A WORKED EXAMPLE
B SLOPPY SEPARATIONS
C SIMULATION USING PLANT DATA : CASE HISTORIES
TABLES
Absorption & indusrial absorber,Gas Absorption,Equipments,Absorption in chemical Reaction,Absorption in Packed Tower,Absorption for counter current,Choice of Solvent,Continuous Contact Equipment,Height Equivalent to Theoretical Plate,HETP
This document discusses secondary reforming in ammonia and hydrogen/syngas production. It explains that ammonia plants commonly use a secondary reformer fired with air, as the nitrogen from air is useful for ammonia synthesis. However, hydrogen/syngas plants less commonly use secondary reforming because nitrogen cannot be tolerated in the process and an air separation unit may not be available or affordable to provide oxygen. The document outlines the key components of secondary reformers - the burner design, mixing volume, and catalyst - which must all be optimized to improve performance.
This document contains a FAQ on chemical reaction engineering. It provides answers to 19 questions covering topics such as the rate of reaction, types of reactors, orders of reaction, catalysts, feasibility of reactions based on Gibbs free energy, and models used to represent flow in reactors. Key differences between CSTR and PFR reactors are also summarized.
Distillation is a process that separates liquid mixtures into individual fractions based on differences in boiling points. It works by heating the mixture to vaporize components with lower boiling points. There are two main types of distillation columns - batch columns which process feed intermittently, and continuous columns which process a steady stream of feed. Distillation columns contain internals like trays or packings to enhance separation, a reboiler for vaporization, a condenser to cool vapors, and a reflux drum to collect condensed liquids and provide reflux. Separation occurs due to differences in vapor pressure and relative volatility between components in the mixture.
Use and Applications of Membranes
0 INTRODUCTION/PURPOSE
1 SCOPE
2 FIELD OF APPLICATION
3 DEFINITIONS
4 GENERAL
4.1 What is a Membrane Process?
4.2 What does a Membrane look like?
4.3 Why use Membranes?
4.4 Membrane Types and Polymers Used
5 REVERSE OSMOSIS
5.1 Principles of Reverse Osmosis
5.2 Limitations
5.3 Performance
5.4 Costs
5.5 Worked Example
5.6 Applications
6 MICROFILTRATION AND ULTRAFILTRATION
6.1 Microfiltration
6.2 Ultrafiltration
7 PERVAPORATION
7.1 Classes of Application
7.2 Characteristics
7.3 Costs
7.4 Example - Lurgi Design
7.5 Application - Stripping Organics from Water
8 GAS SEPARATION AND VAPOR PERMEATION
8.1 Gas Separation
8.2 Vapor Permeation
9 LESS COMMON MEMBRANE PROCESSES
9.1 Dialysis
9.2 Electrodialysis
9.3 Electrolysis
9.4 Salt Splitting
10 BIBLIOGRAPHY
TABLES
1 UTILITY CONSUMPTION AND COST COMPARISON
COURSE LINK:
https://www.chemicalengineeringguy.com/courses/gas-absorption-stripping/
Introduction:
Gas Absorption is one of the very first Mass Transfer Unit Operations studied in early process engineering. It is very important in several Separation Processes, as it is used extensively in the Chemical industry.
Understanding the concept behind Gas-Gas and Gas-Liquid mass transfer interaction will allow you to understand and model Absorbers, Strippers, Scrubbers, Washers, Bubblers, etc…
We will cover:
- REVIEW: Of Mass Transfer Basics required
- GAS-LIQUID interaction in the molecular level, the two-film theory
- ABSORPTION Theory
- Application of Absorption in the Industry
- Counter-current & Co-current Operation
- Several equipment to carry Gas-Liquid Operations
- Bubble, Spray, Packed and Tray Column equipments
- Solvent Selection
- Design & Operation of Packed Towers
- Pressure drop due to packings
- Solvent Selection
- Design & Operation of Tray Columns
- Single Component Absorption
- Single Component Stripping/Desorption
- Diluted and Concentrated Absorption
- Basics: Multicomponent Absorption
- Software Simulation for Absorption/Stripping Operations (ASPEN PLUS/HYSYS)
----
Please show the love! LIKE, SHARE and SUBSCRIBE!
More likes, sharings, suscribers: MORE VIDEOS!
-----
CONTACT ME
Chemical.Engineering.Guy@Gmail.com
www.ChemicalEngineeringGuy.com
http://facebook.com/Chemical.Engineering.Guy
You speak spanish? Visit my spanish channel -www.youtube.com/ChemEngIQA
The document provides an overview of inplant training at MRPL, including:
- MRPL is a subsidiary of ONGC located in Mangalore, Karnataka.
- The refinery's units include a crude distillation unit, vacuum distillation unit, hydrocracker unit, hydrogen unit, and gas oil hydrodesulfurization unit.
- Each unit is described briefly, outlining its key processes and products. The presentation aims to educate trainees on MRPL's refinery operations and configuration.
After crude oil is desalted and dehydrated, it is separated into fractions through distillation. However, the distilled fractions cannot be used directly and require further processing due to differences between crude oil properties and market needs. The complexity of refining processes is also due to environmental regulations that require cleaner products. Distillation involves heating crude oil to separate it based on boiling points, but the distilled fractions need additional conversion processes before they can be used or sold.
This document discusses the classification and selection of chemical reactors. It outlines the basic types of reactors including batch, continuous stirred-tank (CSTR), and plug flow reactors (PFR). Selection of reactors depends on factors such as the process type (batch, continuous, catalytic), phase (gas, liquid, solid), and required mass and heat transfer rates. For example, batch reactors are used for small batch production while CSTRs are common for liquid reactions requiring mixing. PFRs provide higher efficiency and are used when significant heat transfer is needed. Selection also considers whether the reaction involves single or multiple steps.
Interpretation and Correlation of Viscometric Data
0 INTRODUCTION/PURPOSE
1 SCOPE
2 FIELD OF APPLICATION
3 DEFINITIONS
4 NON-NEWTONIAN FLUID BEHAVIOR
4.1 Introduction
4.2 Classification of Non-Newtonian Fluids
4.3 Caution
5 VISCOMETER MEASUREMENTS FOR
TIME-INDEPENDENT FLUIDS
5.1 Concentric Cylinder Viscometers
5.2 Cone and Plate Viscometers
5.3 Parallel Plate Viscometer
5.4 Tube or Capillary Viscometer
5.5 Checks for Consistency of Data and Interpretation
5.6 Estimate of Process Shear Rate
6 MODEL FITTING TO FLOW CURVES
6.1 Power Law
6.2 Bingham Plastic
6.3 Direct use of Numerical Data
6.4 Rheological Models Involving Temperature Dependence
7 CHARACTERIZATION OF TIME-DEPENDENT LIQUIDS
7.1 Sample Loading
7.2 Tests at Constant Shear Rate
7.3 Dynamic Response Measurement
7.4 Changes in Shear Rate
7.4 Concluding Remarks
8 TECHNIQUES FOR CHARACTERIZATION OF
VISCOELASTIC LIQUIDS
8.1 Stress Relaxation
8.2 Oscillatory Shear Measurements
8.3 Normal Force Measurement
8.4 Elongational Viscosity Measurement
9 NOMENCLATURE
10 BIBLIOGRAPHY
APPENDICES
A EQUATIONS FOR VISCOMETERS
A.1 EQUATIONS FOR CONCENTRIC CYLINDER
VISCOMETERS
A.2 EQUATIONS FOR CONE AND PLATE VISCOMETERS
A.3 EQUATIONS FOR PARALLEL PLATE VISCOMETER
A.4 EQUATIONS FOR TUBE OR CAPILLARY VISCOMETER
Gas Solid Mixing
0 INTRODUCTION/PURPOSE
1 SCOPE
2 FIELD OF APPLICATION
3 DEFINITIONS
4 GAS-SOLID FLUIDIZED BED
5 MIXING IN FLUIDIZED BEDS
5.1 Group A Powders
5.2 Group B Powders
5.3 Group C Powders
5.4 Group D Powders
6 MECHANISMS OF MIXING AND SEGREGATION
6.1 Particle Segregation
6.2 Rate of Mixing
6.3 Solids Circulation
7 GRID DESIGN
7.1 Choice of Configuration
8 PLENUM CHAMBER DESIGN
9 SPOUTED BED
10 NOMENCLATURE
11 BIBLIOGRAPHY
FIGURES
1 POWDER CLASSIFICATION DIAGRAM FOR
FLUIDIZATION BY AIR
2 DIAGRAMMATIC REPRESENTATION OF MIXING BY A SINGLE RISING BUBBLE IN A BED OF SMALL
PARTICLES
3 SEGREGATION PATTERNS WITH 'PRACTICAL'
MATERIALS
4 SPOUTED BED – DIAGRAMMATIC
This document provides guidance on mixing dry particulate solids. It discusses key differences between mixing solids versus liquids and gases. Namely, solids have no diffusion, particle properties can cause non-random movement, and particles are much larger than molecules. The document also covers qualitative and quantitative ways to assess mixture quality, such as scale of segregation and variance. It provides equations to calculate the theoretical best mixture quality based on formulation and scale of scrutiny. Selection of an appropriate mixer depends on whether the solids are free-flowing or cohesive. Sampling methods are important to properly assess mixture quality.
Gas-Solid-Liquid Mixing Systems
0 INTRODUCTION/PURPOSE
1 SCOPE
2 FIELD OF APPLICATION
3 DEFINITIONS
4 SELECTION OF EQUIPMENT
5 THREE-PHASE MASS TRANSFER WITH CHEMICAL REACTION
6 STIRRED VESSEL DESIGN
6.1 Agitator Design
6.2 Design for Solids Suspension
6.3 Vessel Design
6.4 Gas-Liquid Mass Transfer Coefficient and Surface Area
7 THREE-PHASE FLUIDIZED BEDS
7.1 Gas and Liquid Hold-Up
7.2 Calculation Procedure
7.3 Bubble Size
7.4 Mass Transfer
7.5 Heat Transfer
7.6 Elutriation
8 SLURRY REACTORS
8.1 Gas Rate
8.2 Mass Transfer
9 NOMENCLATURE
10 BIBLIOGRAPHY
Hydrogen Compressors
Engineering Design Guide
1 SCOPE
2 PHYSICAL ROPERTIES
2.1 Data for Pure Hydrogen
2.2 Influence of Impurities
3 MATERIALS OF CONSTRUCTION
3.1 Hydrogen from Electrolytic Cells
3.2 Pure Hydrogen
4 DESIGN
4.1 Pulsation
4.2 Bypass
5 TESTING OR COMMISSIONING RECIPROCATING COMPRESSORS
6 LUBRICATION
7 LAYOUT
8 REFERENCES
FIGURES
1 MOLLIER CHART - HYDROGEN
2 COMPRESSIBILITY CHART
3 NELSON DIAGRAM
4 WATER CONTENT IN HYDROGEN FOR OIL-LUBRICATED COMPRESSORS AS GRAMM/M2 SWEPT CYLINDER AREA
Mixing of Immiscible Liquids
0 INTRODUCTION/PURPOSE
1 SCOPE
2 FIELD OF APPLICATION
3 DEFINITIONS
4 EQUIPMENT
4.1 Agitated Tanks
4.2 Flow Mixers
4.3 'High Shear' Mixers
5 SYSTEM PHYSICAL PROPERTIES
5.1 Density
5.2 Viscosity
5.3 Interfacial Tension
6 STIRRED VESSELS
6.1 Design for Complete Dispersion
6.2 Prediction of Phase Inversion
6.3 Design for Mass Transfer
6.4 Design for Dispersed Phase Mixing
6.5 Hold-Up in Continuous Vessels
7 FLOW MIXERS
7.1 Design for Turbulent Conditions
7.2 Design for Laminar Conditions
TABLES
1 REYNOLDS NUMBER RANGES
FIGURES
1 STANDARD TANK CONFIGURATION
2 EXPERIMENTAL RELATIONSHIP BETWEEN MASS
TRANSFER COEFFICIENT AND POWER DENSITY
Gas Mixing
0 INTRODUCTION/PURPOSE
1 SCOPE
2 FIELD OF APPLICATION
3 DEFINITIONS
4 RECOMMENDATIONS FOR GAS MIXING:
PLUG FLOW
5 RECOMMENDATIONS FOR GAS MIXING:
BACKMIXED INITIAL ZONE
6 BIBLIOGRAPHY
Distillation Sequences, Complex Columns and Heat IntegrationGerard B. Hawkins
Distillation Sequences, Complex Columns and Heat Integration
0 INTRODUCTION/PURPOSE
1 SCOPE
2 FIELD OF APPLICATION
3 DEFINITIONS
4 SEQUENCING OF SIMPLE COLUMNS
4.1 Sidestream Columns
4.2 Multi-Feed Columns
5 SIMPLE COLUMN SEQUENCING AND HEAT
INTEGRATION INTERACTIONS
5.1 Energy Quantity and Quality
5.2 Heat Integration within the Total Flowsheet
6 COMPLEX COLUMN ARRANGEMENTS
6.1 Indirect Sequence with Vapor Link
6.2 Sidestream Systems
6.3 Pre-Fractionator Systems
7 COMPLEX COLUMNS AND HEAT INTEGRATION
INTERACTIONS
FIGURES
1 DIRECT AND INDIRECT SEQUENCES
2 A SINGLE SIDESTREAM COLUMN REPLACING 2
SIMPLE COLUMNS
3 A TYPICAL MULTI-FEED COLUMN
4 TYPICAL GRAND COMPOSITION CURVE
5 TYPICAL INDIRECT SEQUENCE WITH VAPOUR LINK
6 SIDESTREAM STRIPPER AND SIDESTREAM
RECTIFIER
7 SIMPLEST PRE-FRACTIONATOR SYSTEM
8 SIMPLEST PRE-FRACTIONATOR SYSTEM
9 PETLYUK COLUMN
Control of Continuous Distillation Columns
0 INTRODUCTION/PURPOSE
1 SCOPE
2 FIELD OF APPLICATION
3 DEFINITIONS
4 GENERAL DESCRIPTION OF A DISTILLATION COLUMN
5 REGULATORY CONTROL
5.1 Composition Control
5.2 Mass Balance Control
5.3 Design of Feedback Control Systems
5.4 Pressure and Condensation Control
5.5 Reboiler Control
6 DISTURBANCE COMPENSATION
6.1 Feed-forward Control
6.2 Cascade Control
6.3 Internal Reflux Control
7 CONSTRAINT CONTROL
7.1 Override Controls
7.2 Flooding
7.3 Limiting Control
8 MORE ADVANCED TOPICS
8.1 Temperature Position Control
8.2 Inferential Measurement
8.1 Floating Pressure Control
8.2 Model Based Predictive Control
8.1 Control of Side-streams
8.2 Extractive/Azeotropic Systems
9 REFERENCES
TABLES
1 SYMPTOMS OF IMBALANCE AND THE REGULATORY VARIABLES
2 PRACTICAL LINKAGES BETWEEN CONTROL
(P, R, B, C) AND REGULATION VARIABLES
(h, r, d, b, c, v)
3 COMPOSITION REGULATION
4 COMPOSITION REGULATION - VERY SMALL FLOWS
Mixing of Solid-Liquid Systems
0 INTRODUCTION/PURPOSE
1 SCOPE
2 FIELD OF APPLICATION
3 DEFINITIONS
4 TYPICAL APPLICATIONS
5 AGITATED VESSELS
5.1 Suspension of Heavier-than-Liquid Solids
5.1.1 Dispersion
5.1.2 Agitator Speed Correlation
5.2 Floating Solids
5.3 Mass Transfer
6 JET MIXING FOR SOLID LIQUID AGITATION
6.1 Flat Bottomed Vessel
6.2 Changes in the Shape of the Vessel Base
7 NOMENCLATURE
8 BIBLIOGRAPHY
APPENDICES
A WORKED EXAMPLE
TABLES
1 VALUES OF Po AND ZWIETERING CONSTANT "S"
FOR USE IN EQUATION 1
FIGURES
1 RECOMMENDED CONFIGURATION
2 RECOMMENDED CONFIGURATION FOR DRAW-DOWN OF FLOATING SOLIDS IN AGITATED VESSEL
3 ALTERNATIVE RECOMMENDED CONFIGURATION
FOR DRAW-DOWN OF FLOATING SOLIDS IN FOR
AGITATED VESSEL
4 JET MIXING FOR SOLIDS SUSPENSION
5 ESTIMATION OF S FROM KNOWN DATA
Selection of Heat Exchanger Types
0 INTRODUCTION/PURPOSE
1 SCOPE
2 FIELD OF APPLICATION
3 DEFINITIONS
4 BACKGROUND
5 FACTORS INFLUENCING SELECTION
5.1 Type of Duty
5.2 Temperatures and Pressures
5.3 Materials of Construction 5.4 Fouling
5.5 Safety and Reliability
5.6 Repairs
5.7 Design Methods
5.8 Dimensions and Weight
5.9 Cost
5.10 GBHE Experience
6 TYPES OF EXCHANGER
6.1 Shell and Tube Exchangers
6.2 Cylindrical Graphite Block Heat Exchangers
6.3 Cubic Graphite Block Heat Exchangers
6.4 Air Cooled Heat Exchangers
6.5 Gasketed Plate and Frame
6.6 Spiral Plate
6.7 Tube in Duct
6.8 Plate-fin
6.9 Printed Circuit Heat Exchanger (PCHE)
6.10 Scraped Surface/Wiped Film Exchangers
6.11 Welded or Brazed Plate
6.12 Double Pipe
6.13 Electric Heaters
6.14 Fired Process Heaters
TABLE
(1) ADVANTAGES AND DISADVANTAGES OF DIFFERENT SHELL AND TUBE DESIGNS
FIGURES
1 ESTIMATED MAIN PLANT ITEM COSTS
2 ESTIMATED INSTALLED COSTS
3 TEMA HEAT EXCHANGER NOMENCLATURE
4 F ‘CORRECTION FACTORS' : TEMA E SHELL WITH EVEN NUMBER OF PASSE
5 SHELL AND TUBE HEAT EXCHANGER HEAD TYPES
6 GENERAL ARRANGEMENT OF A CYLINDRICAL GRAPHITE BLOCK HEAT EXCHANGER
7 EXPLODED VIEW OF A CUBIC GRAPHITE BLOCK
HEAT EXCHANGER
8 TYPICAL AIR COOLED HEAT EXCHANGER
9 GENERAL VIEW OF ONE END OF A 3-STREAM
PLATE-FIN HEAT EXCHANGER
10 TYPICAL PCHE PLATE
11 VICARB ‘COMPABLOC' EXCHANGER
12 ‘BROWN FINTUBE' MULTITUBE HEAT EXCHANGER
13 FIRED HEATER : SCHEMATICS AND NOMENCLATURE
Selection and Design of Condensers
0 INTRODUCTION/PURPOSE
1 SCOPE
2 FIELD OF APPLICATION
3 DEFINITIONS
4 CHOICE OF COOLANT
5 LAYOUT CONSIDERATIONS
5.1 Distillation Column Condensers
5.2 Other Process Condensers
6 CONTROL
6.1 Distillation Columns
6.2 Water Cooled Condensers
6.3 Refrigerant Condensers
7 GENERAL DESIGN CONSIDERATIONS
7.1 Heat Transfer Resistances
7.2 Pressure Drop
7.3 Handling of Inerts
7.4 Vapor Inlet Design
7.5 Drainage of Condensate
8 SUMMARY OF TYPES AVAILABLE
8.1 Direct Contact Condensers
8.2 Shell and Tube Exchangers
8.3 Air Cooled Heat Exchangers
8.4 Spiral Plate Heat Exchangers
8.5 Internal Condensers
8.6 Plate Heat Exchangers
8.7 Plate-Fin Heat Exchangers
8.8 Other Compact Designs
9 BIBLIOGRAPHY
FIGURES
1 DIRECT CONTACT CONDENSER WITH INDIRECT COOLER FOR RECYCLED CONDENSATE
2 SPRAY CONDENSER
3 TRAY TYPE CONDENSER
4 THREE PASS TUBE SIDE CONDENSER WITH INTERPASS LUTING FOR CONDENSATE DRAINAGE
5 CROSS FLOW CONDENSER WITH SINGLE PASS COOLANT
This document provides an overview and agenda for a two-day course on industrial mixing technology and equipment. The course objectives are to share knowledge and experience on industrial mixing, discuss best practices, and address challenges in the industry. The course will cover fundamentals of mixing liquids, solids, and high viscosity materials. It will discuss mixing theory, equipment selection and design, advances in technology, and solving mixing problems. Case studies will examine challenges in polymer, food, pharmaceutical, and other industries and how customized mixing solutions improved product quality and profits. The document outlines the course contents which include modules on mixing concepts, fluid mixing, solid mixing, scale-up considerations, and mechanical design of mixers. Key mixing concepts like batch vs continuous
Filtration
0 INTRODUCTION
1 The Theory Underlying Filtration Processes
1.1 The Mechanism of Simple Filtration Systems
1.1.2 Cake Filtration
1.1.3 Complete Blocking
1.1.4 Standard Blocking
1.1.5 Intermediate Blocking
1.2 Cake Filtration – Models and Mechanisms
1.2.1 Classical Theory for the Permeability of Porous Cakes and Beds
1.2.2 The Rate of Filtration through a Compressible Cake – The Standard Filtration Equation
1.2.3 The Compression or Consolidation of Filter Cakes – Ultimate degree of dewatering
1.2.4 The Rate of Consolidation
1.2.5 Useful Semi-Empirical Relations for Constant Pressure and Constant Rate Cake Filtration
1.2.6 Constant Pressure Filtration
1.2.7 Constant Rate Filtration
1.2.8 Multiphase Theory of Filtration
1.3 Crossflow Filtration
2 The Range and Selection of Filtration Equipment Technology
2.1 Scale
2.2 Solids Recovery, Liquids Clarification or Feed stream Concentration
2.3 Rate of Sedimentation
2.4 Rate of Cake Formation and Drainage
2.5 Batch vs Continuous Operation
2.6 Solids Loading
2.7 Further Processing
2.8 Aseptic or “Hygienic” Operation
2.9 Miscellaneous
2.10 Shear versus Compressional Deformation
2.11 Pressure versus Vacuum
3 Suspension Conditioning Prior to Filtration
3.1 Simple Filtration Aids
3.2 Mechanical Treatments
4 Post-Filtration Treatments and Further Downstream Processing
4.1 Washing
4.1.1 Air-Blowing
4.1.2 Drying
5 Testing and Characterization of Suspensions
5.1 Introduction – Suspension
5.2 Properties relevant to Filtration Performance
5.2.1 Pre-Filtration Properties of Suspension
5.2.2 Properties of Filter Cake
5.2.3 Laboratory Scale Filtration Rigs
5.3 Means of Monitoring Flocculant Dosage
5.4 Filter Cake Testing
5.4.1 Strength Testing (See also piston press described earlier)
5.4.2 Cake Permeability or Resistance
5.4.3 Rate of Cake Formation
6 Examples of the Application of the Forgoing Principles
6.1 Dewatering of Calcium Carbonate Slurries
6.2 Dewatering of Organic Products – Procion Dyestuffs
6.3 Filtration of Biological Systems – Harvesting a Filamentous Organism
References
Tables
Figures
SYNOPSIS
The principles underlying centrifugal separation of particulate species are briefly considered, and the main types of separator available are noted. The procedures available for scale-up from laboratory or semi-technical data are then discussed in detail with particular reference to perhaps the most important class of machine for fine particle processing: the disc-nozzle centrifuge.
Starting with the basic concepts behind their design, discussion follows to explain the factors which may limit centrifuge performance. It is shown how a few simple; laboratory scale tests can give a valuable insight into the design and operation of full-scale industrial machines.
Batch Distillation
1 SCOPE
2 FIELD OF APPLICATION
3 DEFINITIONS
4 BACKGROUND TO THE DESIGN
4.1 General
4.2 Choice of batch/continuous operation
4.3 Boiling point curve and cut policy
4.4 Method of design
4.5 Scope of calculations required for design
5 SIMPLE BATCH DISTILLATION
6 FRACTIONAL BATCH DISTILLATION
6.1 General
6.2 Approximate methods
6.3 Rigorous design - use of a computer model
6.4 Other factors influencing the design
6.4.1 Occupation
6.4.2 Choice of Batch Rectification or Stripping
6.4.3 Batch size
6.4.4 Initial estimate of cut policy
6.4.5 Liquid Holdup
6.4.6 Total reflux operation and heating-up time
6.4.7 Column operating pressure
6.5 Optimum Design of the Batch Still
6.6 Special design problems
7 GENERAL ASPECTS OF EQUIPMENT DESIGN
7.1 Kettle reboilers
7.2 Column Internals
7.3 Condensers and reflux split boxes
8 PROCESS CONTROL AND INSTRUMENTATION IN
BATCH DISTILLATION
9 MECHANICAL DESIGN FEATURES
10 BIBLIOGRAPHY
APPENDICES
A McCABE - THIELE METHOD - TYPICAL EXAMPLE
How to Use the GBHE Mixing Guides
0 INTRODUCTION/PURPOSE
1 SCOPE
2 FIELD OF APPLICATION
3 DEFINITIONS
4 THE MIXING GUIDES
4.1 Mixing Guides
4.2 GBHE Mixing and Agitation Manual
5 DEVICE SELECTION
6 MIXING QUESTIONNAIRE
6.1 What is being mixed?
6.2 Why is it being mixed?
6.3 How is it to be mixed?
6.4 Is Heat Transfer Important?
6.5 Is Mixing Time Important?
6.6 Is Inventory Important?
6.7 Is Subsequent Phase Separation Important?
6.8 What Quantities?
6.9 What are the Selection Criteria?
6.10 What Data are required?
7 BASICS
7.1 Bulk Movement
7.2 Shear and Elongation
7.3 Turbulent Diffusion
7.4 Molecular Diffusion
7.5 Mixing Mechanisms
APPENDICES
A ROTATING MIXING DEVICES
B MIXING DEVICES WITHOUT MOVING PARTS
This document provides guidance on implementing procedures for managing critical pressure systems as outlined in PEG 4. It covers the design, manufacture, repair, modification and periodic examination of pressure vessels, piping systems, and pressure relief streams. Key requirements include using recognized standards, qualified personnel, design verification, registration of equipment, and periodic inspections to ensure safety. The document is intended to support the development of detailed local engineering procedures for managing pressure equipment over its lifecycle.
The Preliminary Choice of Fan or Compressor
0 INTRODUCTION/PURPOSE
1 SCOPE
2 FIELD OF APPLICATION
3 DEFINITIONS
4 METHOD FOR PRELIMINARY SELECTION
OF COMPRESSOR
5 PROCESS DATA SHEET
5.1 Essential Data for the Completion of a
Process Data Sheet
5.2 Gas Properties
5.3 Discharge Requirements
6 PRELIMINARY CHOICE OF FAN AND
COMPRESSOR TYPE
6.1 Essential Data for Preliminary Selection
7 FAN AND COMPRESSOR APPLICATIONS
7.1 Fans
7.2 Centrifugal Compressors
7.3 Axial Compressors
7.4 Reciprocating Compressors
7.5 Screw Compressors
7.6 Positive Displacement Blowers
7.7 Sliding Vane Compressors
7.8 Liquid Ring Compressors
8 PROVISION OF INSTALLED SPARES
9 PRELIMINARY ESTIMATE OF COSTS
Process Synthesis
INTRODUCTION
1 A SUGGESTED GENERAL APPROACH
2 EXAMPLES OF PROCESS SELECTION
2.1 Harvesting and Thickening of Single Cell Protein
2.2 Dewatering of a Specialty Latex
3 REFERENCES
TABLES
1 THE ADVANTAGES AND DISADVANTAGES OF DIFFERENT RANGE OF PH FOR “PROTEIN” ORGANISM FLOCCULATION
2 THE ADVANTAGES AND DISADVANTAGES OF VARYING EXTENTS OF CELL BREAKAGES
3 PREDICTED AND OBSERVED FILTER CAKE SOLIDS CONTENTS FOR THE VARIOUS LATICES AFTER COAGULATION
FIGURES
1 THE “PROTEIN” BACTERIAL HARVESTING SYSTEM
2 PROCESS FOR MANUFACTURE OF CALCIUM CARBONATE FILTERS
3 H-ACID ISOLATION
4 A SUGGESTED APPROACH TO DETERMINING FEASIBLE PROCESS OPTIONS, AND OPERATING CONDITIONS FOR SEPARATION OF FINE SOLIDS FROM SUSPENSION
5 MODULI VERSUS SOLIDS CONTENT FORTYPICAL FORWARD FLOCCULATED “PROTEIN” SUSPENSIONS
6 DECISION TREE FOR SELECTION OF AS1 HARVESTING CONDITIONS WHEN PRINCIPAL CONSTRAINT CONCERNS THE DEGREE OF THICKENING REQUIRED IN THE CONCENTRATE
7 DECISION TREE FOR SELECTION OF AS1 HARVESTING CONDITIONS WHEN PRINCIPAL CONSTRAINT CONCERNS THE USE OF FLOTATION AS A UNIT OPERATION FOR THICKENING
8 DECISION TREE FOR SELECTION OF AS1 HARVESTING CONDITIONS WHEN PRINCIPAL CONSTRAINT CONCERNS THE QUALITY OF THE RECYCLED LIQUOR
9 MODULUS SOLIDS CONTENT CURVES FOR THEVARIOUS COAGULATED LATICES
DESIGN OF VENT GAS COLLECTION AND DESTRUCTION SYSTEMS Gerard B. Hawkins
DESIGN OF VENT GAS COLLECTION AND DESTRUCTION SYSTEMS
CONTENTS
1 INTRODUCTION
1.1 Purpose
1.2 Scope of this Guide
1.3 Use of the Guide
2 ENVIRONMENTAL ISSUES
2.1 Principal Concerns
2.2 Mechanisms for Ozone Formation
2.3 Photochemical Ozone Creation Potential
2.4 Health and Environmental Effects
2.5 Air Quality Standards for Ground Level Concentrations of Ozone, Targets for Reduction of VOC Discharges and Statutory Discharge Limits
3 VENTS REDUCTION PHILOSOPHY
3.1 Reduction at Source
3.2 End-of-pipe Treatment
4 METHODOLOGY FOR COLLECTION & ASSESSMENT OF PROCESS FLOW DATA
4.1 General
4.2 Identification of Vent Sources
4.3 Characterization of Vents
4.4 Quantification of Process Vent Flows
4.5 Component Flammability Data Collection
4.6 Identification of Operating Scenarios
4.7 Quantification of Flammability Characteristics for Combined Vents
4.8 Identification, Quantification and Assessment of Possibility of Air Ingress Routes
4.9 Tabulation of Data
4.10 Hazard Study and Risk Assessment
4.11 Note on Aqueous / Organic Wastes
4.12 Complexity of Systems
4.13 Summary
5 SAFE DESIGN OF VENT COLLECTION HEADER SYSTEMS
5.1 General
5.2 Process Design of Vent Headers
5.3 Liquid in Vent Headers
5.4 Materials of Construction
5.5 Static Electricity Hazard
5.6 Diversion Systems
5.7 Snuffing Systems
6 SAFE DESIGN OF THERMAL OXIDISERS
6.1 Introduction
6.2 Design Basis
6.3 Types of High Temperature Thermal Oxidizer
6.4 Refractories
6.5 Flue Gas Treatment
6.6 Control and Safety Systems
6.7 Project Program
6.8 Commissioning
6.9 Operational and Maintenance Management
APPENDICES
A GLOSSARY
B FLAMMABILITY
C EXAMPLE PROFORMA
D REFERENCES
DOCUMENTS REFERRED TO IN THIS PROCESS GUIDE
TABLE
1 PHOTOCHEMICAL OZONE CREATION POTENTIAL REFERENCED
TO ETHYLENE AS UNITY
FIGURES
1 SCHEMATIC OF TYPICAL VENT COLLECTION AND THERMAL OXIDIZER SYSTEM
2 TYPICAL KNOCK-OUT POT WITH LUTED DRAIN
3 SCHEMATIC OF DIVERSION SYSTEM
4 CONVENTIONAL VERTICAL THERMAL OXIDIZER
5 CONVENTIONAL OXIDIZER WITH INTEGRAL WATER SPARGER
6 THERMAL OXIDIZER WITH STAGED AIR INJECTION
7 DOWN-FIRED UNIT WITH WATER BATH QUENCH
8 FLAMELESS THERMAL OXIDATION UNIT
9 THERMAL OXIDIZER WITH REGENERATIVE HEAT RECOVERY
10 TYPICAL PROJECT PROGRAM
11 TYPICAL FLAMMABILITY DIAGRAM
12 EFFECT OF DILUTION WITH AIR
13 EFFECT OF DILUTION WITH AIR ON 100 Rm³ OF FLAMMABLE GAS
Fixed Bed Reactor Scale-up Checklist
The purpose of this checklist is to identify the stages and potential problems associated with the scale up of fixed bed reactors from the drawing board to the full scale plant, and to determine how they should be checked.
The checking can be done using various methods. These are:
• Literature data.
• Lab testing.
• Calculation.
• Modeling.
• Semi-tech testing.
• Piloting or Sidestream testing.
Identifying the stages that need to be addressed for a particular catalyst/reactor development will help in estimating the time needed for the development of the reactor
Data Sources For Calculating Chemical Reaction EquilibriaGerard B. Hawkins
Data Sources For Calculating Chemical Reaction Equilibria
0 INTRODUCTION/PURPOSE
1 SCOPE
2 FIELD OF APPLICATION
3 DEFINITIONS
4 BACKGROUND TO THEORY
5 BIBLIOGRAPHY
Troubleshooting in Distillation Columns
0 INTRODUCTION/PURPOSE
1 SCOPE
2 FIELD OF APPLICATION
3 DEFINITIONS
4 FLOW DIAGRAM FOR TROUBLESHOOTING
5 GENERAL APPRAISAL OF PROBLEM
5.1 Is the Problem Real?
5.2 What Is the Magnitude of the Problem?
5.3 Is it the Column or the Associated Equipment which is Causing the Problem?
6 PROBLEMS IN THE COLUMN
6.1 Capacity Problems
6.2 Efficiency Problems
7 PROBLEMS OUTSIDE THE COLUMN
7.1 Effect of Other Units on Column Performance
7.2 Column Control System
7.3 Improper Operating Conditions
7.4 Auxiliary Equipment
8 USEFUL BACKGROUND READING
9 BIBLIOGRAPHY
FIGURES
1 FLOW DIAGRAM FOR TROUBLESHOOTING
2 DETERMINATION OF COLUMN CAPACITY
"SEDIMENTATION"
INTRODUCTION - THE PHENOMENON OF SEDIMENTATION
Sedimentation is the physical process whereby solid particles, of greater density than their suspending medium, will tend to separate into regions of higher concentration under the influence of gravity. As a solids/liquids separation technique it therefore possesses the great advantage of utilizing a natural, and therefore costless, driving force. This section of the suspension processing Guide is Intended to provide an Introduction to the science of the subject, and the means to judge where and how best to exploit sedimentation as a separation (or other processing) technique.
As a scientific discipline the subject of sedimentation is vast with perspectives ranging from the field of chemical engineering through to theoretical physics being covered In the literature [1-11]. Good reviews of the subject, with a bias towards the engineering aspects, have been written by Fitch and Koz [12, 13]. A short summary of some of the more relevant contributions from the literature is also provided in GBHE-SPG-PEG-302 “Basic Principles & Test Methods”, of the Suspensions Processing Guides.
.
The sedimentation process is traditionally divided into ..."
Chemical Process Conception
0 INTRODUCTION / PURPOSE
1 SCOPE
2 FIELD OF APPLICATION
3 DEFINITIONS
4 PRODUCT STRATEGY
4.1 General
4.2 Market for the Product
4.3 Production Costs
4.4 Process Technology
5 PRELIMINARY PROCESS INFORMATION
6 REACTION AND REACTOR
6.1 Batch vs Continuous
6.2 Multiple Reactors
7 RECYCLE
7.1 Recycle Structure
7.2 Classification of Chemicals
7.3 Effect of Recycle
7.4 Preliminary Estimation of Conversion
8 REACTOR TYPE AND PERFORMANCE
8.1 Conversion-Yield Effects
8.2 Heat Effects
8.3 Equilibrium Effects
8.4 Kinetic Effects
8.5 More Help with Reactor Design
9 SEPARATION SYSTEM
10 REVIEW
11 BIBLIOGRAPHY AND REFERENCES
11.1 Preliminary Flowsheeting
11.2 Physical Properties
11.3 Reactors
11.4 Separation
11.5 Costing
APPENDICES
A BASIC REACTOR SYSTEM DESIGN
B DISCUSSION BETWEEN A CHEMIST AND A
CHEMICAL ENGINEER
C BASIC SEPARATION STRATEGY
TABLES
1 CLASSIFICATION OF MATERIALS
FIGURES
1 FLOWCHART OF THE ITERATIVE PROCEDURE REQUIRED IN PROCESS AND PRODUCT SELECTION AND DEVELOPMENT
VLE Data - Selection and Use
0 INTRODUCTION/PURPOSE
1 SCOPE
2 FIELD OF APPLICATION
3 DEFINITIONS
4 DIAGRAMMATIC REPRESENTATION OF IDEAL
AND NON-IDEAL SYSTEMS
4.1 Ideal Mixtures
4.2 Non-Ideal Mixtures
5 REVIEW OF VLE MODELS
5.1 Ideal Behavior in Both Phases
5.2 Liquid Phase Non-Idealities
5.3 High Pressure Systems
5.4 Special Models
6 SETTING UP A VLE MODEL
6.1 Define Problem
6.2 Select Data
6.3 Select Correlation(s)
6.4 Produce Model
7 AVOIDING PITFALLS
7.1 Experimental Data is Better than Estimates
7.2 Check Validity of Fitted Model
7.3 Check Limitations of Estimation Methods
7.4 Know Your System
7.5 Appreciate Errors and Effects
7.6 If in Doubt – Ask
8 A CASE STUDY
8.1 The Problem
8.2 The System
8.3 Data Available
8.4 Selected Correlation
8.5 Simulation
8.6 Selection of Model
9 RECOMMENDED READING
10 VLE EXPERTS IN GBHE
APPENDICES
A USE OF EXTENDED ANTOINE EQUATION
B USE OF WILSON EQUATION
C USEFUL METHODS OF ESTIMATING
D EQUATIONS OF STATE FOR VLE CALCULATIONS
TABLES
1 SUMMARY OF VLE METHODS
2 LIST OF USEFUL REFERENCES
FIGURES
1 VAPOR-LIQUID EQUILIBRIUM - IDEAL SOLUTION
BEHAVIOR
2 VAPOR-LIQUID EQUILIBRIUM - A GENERALISED
Y-X DIAGRAM
3 VAPOR-LIQUID EQUILIBRIUM - MINIMUM BOILING
AZEOTROPE
4 VAPOR-LIQUID EQUILIBRIUM - MAXIMUM BOILING
AZEOTROPE
5 VAPOR-LIQUID EQUILIBRIUM - MINIMUM BOILING
AZEOTROPE -TWO LIQUID PHASES
6 SENSITIVITY TO ERROR IN VLE DATA (BASED ON FENSKE EQUATION)
7(a) FITTING WILSON 'A' VALUES TO VLE DATA - CASE A
7(b) FITTING WILSON 'A' VALUES TO VLE DATA - CASE B
7(c) FITTING WILSON 'A' VALUES TO VLE DATA - CASE C
The Selection of Flocculants and other Solid-Liquid Separation AidsGerard B. Hawkins
The use of chemical additives, such as flocculants, is a common step in solid-liquid separation operations. The correct selection of agent is an essential part of the design of such processes. Many excellent reviews and guides deal with this topic, and the interested reader is referred to works such as [l-4]. In particular the Harwell-Warren Spring Report “The Use and Selection of Flocculants" provides a good overview on the application of coagulants and flocculants. This section does not attempt to reproduce a detailed treatment of that kind; instead it is our intention to state a few general rules and principles concerning methods of choosing an additive, and to illustrate briefly their application in practice.
The types of agents employed in solid-liquid separation fall into three principal classes:
Biological Systems: A Special Case
Up till now we have discussed various aspects of the separation and processing of fine solids without too much reference (except in the examples) to the specifics of the properties of the materials concerned. Though the material properties are the dominant influence on efficient process design and operation, it has been postulated that the necessary characteristics for process selection and optimization can be found fairly readily using easily-applicable rheological and other techniques. This underlying assumption also seems to hold good for biological suspensions; however, certain aspects of the behavior of these systems are sufficiently specialized for them to merit a separate discussion viz:
1 TYPES OF BIOLOGICAL SEPARATION
1.1 Whole-Organism Case
1.2 Part-Cell Separations
1.3 Isolation of Individual Molecular Species
2 SETTING ABOUT DEVISING AN EFFECTIVE
PROCESS FOR SEPARATION OF A BIOLOGICAL MATERIAL
2.1 Whole-Organism Case
2.1.1 Characterization of Biopolymers in the Liquor
2.1.2 Release of Internal Water
2.2 Part -Cell Separations
2.2.1 Selectivity
2.2.2 Cost
2.3 Isolation of Individual Molecular Species
3 Examples
3.1 Effective Design and Operation of a Process for Harvesting of Single Cell Protein
3.2 Harvesting of Mycoprotein for Human Consumption
3.3 Thickening of a Filamentous Organism Suspension
3.4 Separation of Poly-3-hydroxybutyrate Polymer (PHB) from Alcaligenes Eutrophus Biomass
3.5 Isolation of Organic Acid Produced by an Enzymatic Process
4 REFERENCES
Table
Figures
Air Cooled Heat Exchanger Design
0 INTRODUCTION/PURPOSE
1 SCOPE
2 FIELD OF APPLICATION
3 DEFINITIONS
4 SUITABILITY FOR AIR COOLING
4.1 Options Available For Cooling
4.2 Choice of Cooling System
5 SPECIFICATION OF AN AIR COOLED HEAT
EXCHANGER
5.1 Description and Terminology
5.2 General
5.3 Thermal Duty and Design Margins
5.4 Process Pressure Drop
5.5 Design Ambient Conditions
5.6 Process Physical Properties
5.7 Mechanical Design Constraints
5.8 Arrangement
5.9 Air Side Fouling
5.10 Economic Factors in Design
6 CONTROL
7 PRESSURE RELIEF
8 ASSESSMENT OF OFFERS
8.1 General
8.2 Manual Checking Of Designs
8.3 Computer Assessment
8.4 Bid Comparison
9 FOULING AND CORROSION
9.1 Fouling
9.2 Corrosion
10 OPERATION AND MAINTENANCE
10.1 Performance Testing
10.2 Air-Side Cleaning
10.3 Mechanical Maintenance
10.4 Tube side Access
11 REFERENCES
Centrifugal Compressors
SECTION ONE - ANTI-SURGE PROTECTION AND THROUGHPUT REGULATION
0 INTRODUCTION
1 SCOPE
2 MACHINE CHARACTERISTICS
2.1 Characteristics of a Single Compressor Stage
2.2 Characteristic of a Multiple Stage Having More
Than One Impeller
2.3 Use of Compressor Characteristics in Throughput
Regulation Schemes
3 MECHANISM AND EFFECTS OF SURGE
3.1 Basic Flow Instabilities
3.2 Occurrence of Surge
3.3 Intensity of Surge
3.4 Effects of Surge
3.5 Avoidance of Surge
3.6 Recovery from Surge
4 CONTROL SCHEMES INCLUDING SURGE PROTECTION
4.1 Output Control
4.2 Surge Protection
4.3 Surge Detection and Recovery
5 DYNAMIC CONSIDERATIONS
5.1 Interaction
5.2 Speed of Response of Antisurge Control System
6 SYSTEM EQUIPMENT SPECIFICATIONS
6.1 The Antisurge Control Valve
6.2 Non-return Valve
6.3 Pressure and flow measurement
6.4 Signal transmission
6.5 Controllers
7 TESTING
7.1 Determination of the Surge Line
7.2 Records
8 INLET GUIDE VANE UNITS
8.1 Application
8.2 Effect on Power Consumption of the Compressor
8.3 Effect of Gas Conditions, Properties and Contaminants
8.4 Aerodynamic Considerations
8.5 Control System Linearity
8.6 Actuator Specification
8.7 Avoidance of Surge
8.8 Features of Link Mechanisms
8.9 Limit Stops and Shear Links
APPENDICES
A LIST OF SYMBOLS AND PREFERRED UNITS
B WORKED EXAMPLE 1 COMPRESSOR WITH VARIABLE INLET PRESSURE AND VARIABLE GAS COMPOSITION
C WORKED EXAMPLE 2 A CONSTANT SPEED ~ STAGE COMPRESSOR WITH INTER-COOLING
D WORKED EXAMPLE 3 DYNAMIC RESPONSE OF THE ANTISURGE PROTECTION SYSTEM FOR A SERVICE AIR COMPRESSOR RUNNING AT CONSTANT SPEED
E EXAMPLE OF INLET GUIDE VANE REGULATION
FIGURES
2.1 TYPICAL COMPRESSOR STAGE CHARACTERISTIC PLOTTED WITH FLOW AT DISCHARGE CONDITIONS
2.2 TYPICAL COMPRESSOR STAGE CHARACTERISTIC PLOTTED WITH FLOW AT INLET CONDITIONS
2.3 PERFORMANCE CHARACTERISTICS OF A COMPRESSOR STAGE AT VARYING SPEEDS
2.4 SYSTEM WORKING POINT DEFINED BY INTERSECTION OF PROCESS AND COMPRESSOR CHARACTERISTICS
2.5 DISCHARGE THROTTLE REGULATION
2.6 BYPASS REGULATION
2.7 INLET THROTTLE REGULATION
2.8 INLET GUIDE VANE REGULATION
2.9 VARIABLE SPEED REGULATION
3.1 GAS PULSATION LEVELS FOR A CENTRIFUGAL COMPRESSOR
3.2 REPRESENTATION OF CYCLIC FLOW DURING SURGE OF LONG PERIOD
3.3 TYPICAL WAVEFORM OF DISCHARGE PRESSURE DURING SURGE
3.4 MULTIPLE SURGE LINE FOR A MULTISTAGE CENTRIFUGAL COMPRESSOR
3.5 TYPICAL MULTIPLE SURGE LINES FOR SINGLE STAGE AXIAL-FLOW COMPRESSOR
4.1 GENERAL SCHEMATIC FOR COMPRESSORS OPERATING IN PARALLEL TO FEED MULTIPLE USER PLANTS
4.2 ILLUSTRATION OF SAFETY MARGIN BETWEEN SURGE POINT AND SURGE PROTECTION POINT AT WHICH ANTISURGE SYSTEM IS ACTIVATED
4.3 ANTISURGE SYSTEM FOR COMPRESSOR WITH FLAT PERFO ..........
Overflows and Gravity Drainage Systems
0 INTRODUCTION/PURPOSE
1 SCOPE
2 FIELD OF APPLICATION
3 DEFINITIONS
4 OUTLINE OF THE PROBLEM
5 DESIGNING FOR FLOODED FLOW
6 DESIGNING NON-FLOODED PIPELINES
6.1 Vertical Pipework
6.2 From the Side of a Vessel
6.3 Established (uniform) Flow in Near-horizontal Pipes
6.4 Non-uniform Flow
7 NON-FLOODED FLOW IN COMPLEX SYSTEMS
8 ENTRAINING FLOW
9 SIMPLE TANK OVERFLOWS
9.1 Venting of the Tank
10 BIBLIOGRAPHY
11 NOMENCLATURE
TABLE
1 GEOMETRICAL FUNCTIONS OF PART-FULL PIPES
FIGURES
1 TYPICAL SEQUENCE OF SURGING FLOW
2 DESIGNING FOR FLOODED FLOW
3 CAPACITY OF SLOPING PIPELINES
4 OVERFLOW FROM SIDE OF VESSEL
5 METHODS OF AVOIDING LARGE CIRCULAR SIDE
OVERFLOWS
6 CAPACITY OF A GENTLY SLOPING PIPE AS A FUNCTION OF LIQUID DEPTH
7 COMPLEX PIPE SYSTEMS
8 REMOVAL OF ENTRAINED GASES
Pressure Relief Systems Vol 2
Causes of Relief Situations
This Volume 2 is a guide to the qualitative identification of common causes of overpressure in process equipment. It cannot be exhaustive; the process engineer and relief systems team should look for any credible situation in addition to those given in this Part which could lead to a need for pressure relief (a relief situation).
This document provides guidelines for engineering design of pressure relief systems. It discusses key principles such as identifying potential overpressure and underpressure causes, sizing relief systems to prevent hazards, and safely disposing of relieved materials. The guidelines cover statutory requirements, recommended design procedures, and documentation standards. The overall goal is to preserve equipment integrity and prevent failure from over or under pressure during all process phases.
GAS DISPERSION - A Definitive Guide to Accidental Releases of Heavy GasesGerard B. Hawkins
GAS DISPERSION - A Definitive Guide to Accidental Releases of Heavy Gases
This Process Safety Guide has been written with the aim of assisting process engineers, hazard analysts and environmental advisers in carrying out gas dispersion calculations. The Guide aims to provide assistance by:
• Improving awareness of the range of dispersion models available within GBHE, and providing guidance in choosing the most appropriate model for a particular application.
• Providing guidance to ensure that source terms and other model inputs are correctly specified, and the models are used within their range of applicability.
• Providing guidance to deal with particular topics in gas dispersion such as dense gas dispersion, complex terrain, and modeling the chemistry of oxides of nitrogen.
• Providing general background on air quality and dispersion modeling issues such as meteorology and air quality standards.
• Providing example calculations for real practical problems.
SCOPE
The gas dispersion guide contains the following Parts:
1 Fundamentals of meteorology.
2 Overview of air quality standards.
3 Comparison between different air quality models.
4 Designing a stack.
5 Dense gas dispersion.
6 Calculation of source terms.
7 Building wake effects.
8 Overview of the chemistry of the oxides of nitrogen.
9 Overview of the ADMS complex terrain module.
10 Overview of the ADMS deposition module.
11 ADMS examples.
12 Modeling odorous releases.
13 Bibliography of useful gas dispersion books and reports.
14 Glossary of gas dispersion modeling terms.
Appendix A : Modeling Wind Generation of Particulates.
APPENDIX B TABLE OF PROPERTY VALUES FOR SPECIFIC CHEMICALS
101 Things That Can Go Wrong on a Primary Reformer - Best Practices GuideGerard B. Hawkins
This document discusses common problems that can occur in primary reformers and associated equipment. It identifies issues that can lead to plant shutdowns or efficiency losses, grouping them under catalysts, tubes, furnace boxes, burners, flue gas ducts, headers, and refractories. Some examples discussed include carbon formation, tube overheating, flame impingement, leaks in air preheaters, combustion air maldistribution, and damage to coffins. The document provides an overview of these issues to improve plant reliability over its lifespan.
El impacto en el rendimiento del catalizador por envenenamiento y ensuciamien...Gerard B. Hawkins
El documento describe los procesos de refinería y catalizadores, así como los efectos del envenenamiento y ensuciamiento en el rendimiento de los catalizadores. El envenenamiento reduce la actividad de los catalizadores al bloquear los sitios activos o modificar la química de la superficie, lo que afecta la actividad y selectividad. Los niveles bajos de contaminantes tienen un mayor impacto en catalizadores con menor área de superficie. El envenenamiento también puede causar cambios estructurales en el catalizador y permitir
Theory of Carbon Formation in Steam Reforming
Contents
1 Introduction
2 Underpinning Theory
2.1 Conceptualization
2.2 Reforming Reactions
2.3 Carbon Formation Chemistry
2.3.1 Natural Gas
2.3.2 Carbon Formation for Naphtha Feeds
2.3.3 Carbon Gasification
2.4 Heat Transfer
3 Causes
3.1 Effects of Carbon Formation
3.2 Types of Carbon
4 What are the Effects of Carbon Formation?
4.1 Why does Carbon Formation Get Worse?
4.1.1 So what is the Next Step?
4.2 Consequences of Carbon Formation
4.3 Why does Carbon Form where it does?
4.3.1 Effect on Process Gas Temperature
4.4 Why does Carbon Formation Propagate Down the Tube?
4.4.1 Effect on Radiation on the Fluegas Side
4.5 Why does Carbon Formation propagate Up the Tube?
5 How do we Prevent Carbon Formation
5.1 The Role of Potash
5.2 Inclusion of Pre-reformer
5.3 Primary Reformer Catalyst Parameters
5.3.1 Activity
5.3.2 Heat Transfer
5.3.3 Increased Steam to Carbon Ratio
6 Steam Out
6.1 Why does increasing the Steam to Carbon Ratio Not Work?
6.2 Why does reducing the Feed Rate not help?
6.3 Fundamental Principles of Steam Outs
TABLES
1 Heat Transfer Coefficients in a Typical Reformer
2 Typical Catalyst Loading Options
FIGURES
1 Hot Bands
2 Conceptual Pellet
3 Naphtha Carbon Formation
4 Heat Transfer within an Reformer
5 Types of Carbon Formation
6 Effect of Carbon on Nickel Crystallites
7 Absorption of Heat
8 Comparison of "Base Case" v Carbon Forming Tube
9 Carbon Formation Vicious Circle
10 Temperature Profiles
11 Carbon Pinch Point
12 Carbon Formation
13 Effect on Process Gas Temperature
14 How does Carbon Propagate into an Unaffected Zone?
15 Movement of the Carbon Forming Region
16 Effect of Hot Bands on Radiative Heat Transfer
17 Effect of Potash on Carbon Formation
18 Application of a Pre-reformer
19 Effect of Activity on Carbon Formation
Adiabatic Reactor Analysis for Methanol Synthesis Plant Note Book Series: P...Gerard B. Hawkins
The document discusses adiabatic reactor analysis for methanol synthesis from syngas. It provides the reaction kinetics and calculates conversion, temperature, and reactor volume needed at different conversions. Energy and mass balances are used to derive relationships between conversion, temperature and reaction rate. Data is generated to plot conversion versus volumetric flow rate for reactor sizing. The plot indicates a continuous stirred tank reactor (CSTR) could achieve 85% conversion before switching to a plug flow reactor (PFR) for higher conversion with less volume.
STEAMING PROCEDURE FOR VULCAN STEAM REFORMING CATALYSTSGerard B. Hawkins
The document discusses procedures for steaming Vulcan steam reforming catalysts to recover from sulfur poisoning and carbon formation incidents. It describes maintaining steam flow at 30-40% of design levels and an outlet temperature above 780°C. Gas samples should be taken hourly to monitor CO2, CH4, H2S and SO2. Steaming is complete when CO2 levels stabilize over 2-3 samples after increasing the temperature. The process typically takes 12-24 hours to complete and closely monitors pressure drop and tube conditions. After steaming, the catalyst requires reduction before restarting hydrocarbon feed.
Calculation of an Ammonia Plant Energy Consumption: Gerard B. Hawkins
Calculation of an Ammonia Plant Energy Consumption:
Case Study: #06023300
Plant Note Book Series: PNBS-0602
CONTENTS
0 SCOPE
1 CALCULATION OF NATURAL GAS PROCESS FEED CONSUMPTION
2 CALCULATION OF NATURAL GAS PROCESS FUEL CONSUMPTION
3 CALCULATION OF NATURAL GAS CONSUMPTION FOR PILOT BURNERS OF FLARES
4 CALCULATION OF DEMIN. WATER FROM DEMIN. UNIT
5 CALCULATION OF DEMIN. WATER TO PACKAGE BOILERS
6 CALCULATION OF MP STEAM EXPORT
7 CALCULATION OF LP STEAM IMPORT
8 DETERMINATION OF ELECTRIC POWER CONSUMPTION
9 DETERMINATION OF THE TOTAL ENERGY CONSUMPTION OF THE AMMONIA PLANT ISBL
10 ADJUSTMENT OF ELECTRIC POWER CONSUMPTION FOR TEST RUN CONDITIONS
11 CALCULATION OF AMMONIA SHARE IN MP STEAM CONSUMPTION IN UTILITIES
12 CALCULATION OF AMMONIA SHARE IN ELECTRIC POWER CONSUMPTION IN UTILITIES
13 DETERMINATION OF THE TOTAL ENERGY CONSUMPTION OF THE AMMONIA PLANT OSBL
14 DETERMINATION OF THE TOTAL ENERGY CONSUMPTION OF THE AMMONIA PLANT
Ammonia Plant Technology
Pre-Commissioning Best Practices
GBHE-APT-0102
PICKLING & PASSIVATION
CONTENTS
1 PURPOSE OF THE WORK
2 CHEMICAL CONCEPT
3 TECHNICAL CONCEPT
4 WASTES & SAFETY CONCEPT
5 TARGET RESULTS
6 THE GENERAL CLEANING SEQUENCE MANAGEMENT
6.6.1 Pre-cleaning or “Physical Cleaning
6.6.2 Pre-rinsing
6.6.3 Chemical Cleaning
6.6.4 Critical Factors in Cleaning Success
6.6.5 Rinsing
6.6.6 Inspection and Re-Cleaning, if Necessary
7 Systems to be treated by Pickling/Passivation
Ammonia Plant Technology
Pre-Commissioning Best Practices
Piping and Vessels Flushing and Cleaning Procedure
CONTENTS
1 Scope
2 Aim/purpose
3 Responsibilities
4 Procedure
4.1 Main cleaning methods
4.1.1 Mechanical cleaning
4.1.2 Cleaning with air
4.1.3 Cleaning with steam (for steam networks only)
4.1.4 Cleaning with water
4.2 Choice of the cleaning method
4.3 Cleaning preparation
4.4 Protection of the devices included in the network
4.5 Protection of devices in the vicinity of the network
4.6 Water flushing procedure
4.6.1 Specific problems of water flushing
4.6.2 Preparation for water flushing
4.6.3 Performing a water flush
4.6.4 Cleanliness criteria
4.7 Air blowing procedure
4.7.1 Specific problems of air blowing
4.7.2 Preparation for air blowing
4.7.3 Performing air blowing
4.7.4 Cleanliness checks
4.8 Steam blowing procedure
4.8.1 Specific problems of steam blowing
4.8.2 Preparation for steam blowing
4.8.3 Performing steam blowing
4.8.4 Cleanliness checks
4.9 Chemical cleaning procedure
4.9.1 Specific problems of cleaning with a chemical solution
4.9.2 Preparation for chemical cleaning
4.9.3 Performing a chemical cleaning
4.9.4 Cleanliness criteria
4.10 Re-assembly - general guideline
4.11 Preservation of flushed piping
PRACTICAL GUIDE ON THE SELECTION OF PROCESS TECHNOLOGY FOR THE TREATMENT OF A...Gerard B. Hawkins
PRACTICAL GUIDE ON THE SELECTION OF PROCESS TECHNOLOGY FOR THE TREATMENT OF AQUEOUS ORGANIC EFFLUENT STREAMS
CONTENTS
0 INTRODUCTION/PURPOSE
1 SCOPE
2 FIELD OF APPLICATION
3 DEFINITIONS
3.1 IPU
3.2 AOS
3.3 BODs
3.4 COD
3.5 TOC
3.6 Toxicity
3.7 Refractory Organics/Hard COD
3.8 Heavy Metals
3.9 EA
3.10 Biological Treatment Terms
3.11 BATNEEC
3.12 BPEO
3.13 EQS/LV
3.14 IPC
3.15 VOC
3.16 F/M Ratio
3.17 MLSS
3.18 MLVSS
4 DESIGN/ECONOMIC GUIDELINES
5 EUROPEAN LEGISLATION
5.1 General
5.2 Integrated Pollution Control (IPC)
5.3 Best Available Techniques Not Entailing Excessive Costs (BATNEEC)
5.4 Best Practicable Environmental Option (BPEO)
5.5 Environmental Quality Standards(EQS)
6 IPU EXIT CONCENTRATION
7 SITE/LOCAL REQUIREMENTS
8 PROCESS SELECTION PROCEDURE
8.1 Waste Minimization Techniques (WMT)
8.2 AOS Stream Definition
8.3 Technical Check List
8.4 Preliminary Selection of Suitable Technologies
8.5 Process Sequences
8.6 Economic Evaluation
8.7 Process Selection
APPENDICES
A DIRECTIVE 76/464/EEC - LIST 1
B DIRECTIVE 76/464/EEC - LIST 2
C THE EUROPEAN COMMISSION PRIORITY CANDIDATE LIST
D THE UK RED LIST
E CURRENT VALUES FOR EUROPEAN COMMUNITY ENVIRONMENTAL QUALITY STANDARDS AND CORRESPONDING LIMIT VALUES
F ESTABLISHED TECHNOLOGIES
G EMERGING TECHNOLOGY
H PROPRIETARY/LESS COMMON TECHNOLOGIES
J COMPARATIVE COST DATA
PRACTICAL GUIDE ON THE REDUCTION OF DISCHARGES TO ATMOSPHERE OF VOLATILE ORGA...Gerard B. Hawkins
PRACTICAL GUIDE ON THE REDUCTION OF DISCHARGES TO ATMOSPHERE OF VOLATILE ORGANIC COMPOUNDS (VOCs)
FOREWORD
CONTENTS
1 INTRODUCTION
2 THE NEED FOR VOC CONTROL
3 CONTROL AT SOURCE
3.1 Choice or Solvent
3.2 Venting Arrangements
3.3 Nitrogen Blanketing
3.4 Pump Versus Pneumatic Transfer
3.5 Batch Charging
3.6 Reduction of Volumetric Flow
3.7 Stock Tank Design
4 DISCHARGE MEASUREMENT
4.1 By Inference or Calculation
4.2 Flow Monitoring Equipment
4.3 Analytical Instruments
4.4 Vent Emissions Database
5 ABATEMENT TECHNOLOGY
5.1 Available Options
5.2 Selection of Preferred Option
5.3 Condensation
5.4 Adsorption
5.5 Absorption
5.6 Thermal Incineration
5.7 Catalytic Oxidation
5.8 Biological Filtration
5.9 Combinations of Process technologies
5.10 Processes Under Development
6 GLOSSARY OF TERMS
7 REFERENCES
Appendix 1. Photochemical Ozone Creation Potentials
Appendix 2. Examples of Adsorption Preliminary Calculations
Appendix 3. Example of Thermal Incineration Heat and Mass Balance
Appendix 4. Cost Correlations
Getting the Most Out of Your Refinery Hydrogen PlantGerard B. Hawkins
Getting the Most Out of Your Refinery Hydrogen Plant
Contents
Summary
1 Introduction
2 "On-purpose" Hydrogen Production
3 Operational Aspects
4 Uprating Options on the Steam Reformer
4.1 Steam Reforming Catalysts and Tube Metallurgy
4.2 Oxygen-blown Secondary Reformer
4.3 Pre-reforming
4.4 Post-reforming
5 Downstream Units
6 Summary of Uprating Options
7 Conclusions
EMERGENCY ISOLATION OF CHEMICAL PLANTS
CONTENTS
1 Introduction
2 When should Emergency Isolation Valves be Installed
3 Emergency Isolation Valves and Associated Equipment
3.1 Installations on existing plant
3.2 Actuators
3.3 Power to close or power to open
3.4 The need for testing
3.5 Hand operated Emergency Valves
3.6 The need to stop pumps in an emergency
3.7 Location of Operating Buttons
3.8 Use of control valves for Isolation
4 Detection of Leaks and Fires
5 Precautions during Maintenance
6 Training Operators to use Emergency Isolation Valves
7 Emergency Isolation when no remotely operated valve is available
References
Glossary
Appendix I Some Fires or Serious Escapes of Flammable Gases or Liquids that could have been controlled by Emergency Isolation Valves
Appendix II Some typical Installations
Amine Gas Treating Unit - Best Practices - Troubleshooting Guide Gerard B. Hawkins
Amine Gas Treating Unit Best Practices - Troubleshooting Guide for H2S/CO2 Amine Systems
Contents
Process Capabilities for gas treating process
Typical Amine Treating
Typical Amine System Improvements
Primary Equipment Overview
Inlet Gas Knockout
Absorber
Three Phase Flash Tank
Lean/Rich Heat Exchanger
Regenerator
Filtration
Amine Reclaimer
Operating Difficulties Overview
Foaming
Failure to Meet Gas Specification
Solvent Losses
Corrosion
Typical Amine System Improvements
Degradation of Amines and Alkanolamines during Sour Gas Treating
APPENDIX
Best Practices - Troubleshooting Guide
Investigation of the Potential Use of (IILs) Immobilized Ionic Liquids in Sha...Gerard B. Hawkins
The document discusses using immobilized ionic liquids (IILs) in shale gas sweetening reactions. It proposes immobilizing a cobalt catalyst in the surface ionic liquid layer of a solid supported ionic liquid catalyst. This would create a "homogeneous catalyst" dissolved within the fixed IIL layer. Competing reactions like oxidation of sulfides to sulfones would need to be considered. Related work on using similar approaches for hydroformylation reactions is referenced. The concept aims to develop a solid IIL catalyst for sweetening reactions involving oxidation using techniques from other areas like hydroformylation.
Ivanti’s Patch Tuesday breakdown goes beyond patching your applications and brings you the intelligence and guidance needed to prioritize where to focus your attention first. Catch early analysis on our Ivanti blog, then join industry expert Chris Goettl for the Patch Tuesday Webinar Event. There we’ll do a deep dive into each of the bulletins and give guidance on the risks associated with the newly-identified vulnerabilities.
For the full video of this presentation, please visit: https://www.edge-ai-vision.com/2024/06/how-axelera-ai-uses-digital-compute-in-memory-to-deliver-fast-and-energy-efficient-computer-vision-a-presentation-from-axelera-ai/
Bram Verhoef, Head of Machine Learning at Axelera AI, presents the “How Axelera AI Uses Digital Compute-in-memory to Deliver Fast and Energy-efficient Computer Vision” tutorial at the May 2024 Embedded Vision Summit.
As artificial intelligence inference transitions from cloud environments to edge locations, computer vision applications achieve heightened responsiveness, reliability and privacy. This migration, however, introduces the challenge of operating within the stringent confines of resource constraints typical at the edge, including small form factors, low energy budgets and diminished memory and computational capacities. Axelera AI addresses these challenges through an innovative approach of performing digital computations within memory itself. This technique facilitates the realization of high-performance, energy-efficient and cost-effective computer vision capabilities at the thin and thick edge, extending the frontier of what is achievable with current technologies.
In this presentation, Verhoef unveils his company’s pioneering chip technology and demonstrates its capacity to deliver exceptional frames-per-second performance across a range of standard computer vision networks typical of applications in security, surveillance and the industrial sector. This shows that advanced computer vision can be accessible and efficient, even at the very edge of our technological ecosystem.
How to Interpret Trends in the Kalyan Rajdhani Mix Chart.pdfChart Kalyan
A Mix Chart displays historical data of numbers in a graphical or tabular form. The Kalyan Rajdhani Mix Chart specifically shows the results of a sequence of numbers over different periods.
Fueling AI with Great Data with Airbyte WebinarZilliz
This talk will focus on how to collect data from a variety of sources, leveraging this data for RAG and other GenAI use cases, and finally charting your course to productionalization.
Driving Business Innovation: Latest Generative AI Advancements & Success StorySafe Software
Are you ready to revolutionize how you handle data? Join us for a webinar where we’ll bring you up to speed with the latest advancements in Generative AI technology and discover how leveraging FME with tools from giants like Google Gemini, Amazon, and Microsoft OpenAI can supercharge your workflow efficiency.
During the hour, we’ll take you through:
Guest Speaker Segment with Hannah Barrington: Dive into the world of dynamic real estate marketing with Hannah, the Marketing Manager at Workspace Group. Hear firsthand how their team generates engaging descriptions for thousands of office units by integrating diverse data sources—from PDF floorplans to web pages—using FME transformers, like OpenAIVisionConnector and AnthropicVisionConnector. This use case will show you how GenAI can streamline content creation for marketing across the board.
Ollama Use Case: Learn how Scenario Specialist Dmitri Bagh has utilized Ollama within FME to input data, create custom models, and enhance security protocols. This segment will include demos to illustrate the full capabilities of FME in AI-driven processes.
Custom AI Models: Discover how to leverage FME to build personalized AI models using your data. Whether it’s populating a model with local data for added security or integrating public AI tools, find out how FME facilitates a versatile and secure approach to AI.
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Conversational agents, or chatbots, are increasingly used to access all sorts of services using natural language. While open-domain chatbots - like ChatGPT - can converse on any topic, task-oriented chatbots - the focus of this paper - are designed for specific tasks, like booking a flight, obtaining customer support, or setting an appointment. Like any other software, task-oriented chatbots need to be properly tested, usually by defining and executing test scenarios (i.e., sequences of user-chatbot interactions). However, there is currently a lack of methods to quantify the completeness and strength of such test scenarios, which can lead to low-quality tests, and hence to buggy chatbots.
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"Frontline Battles with DDoS: Best practices and Lessons Learned", Igor Ivaniuk
Fluid Separation
1. GBH Enterprises, Ltd.
Process Engineering Guide:
GBHE-PEG-MAS-600
Fluid Separation
Information contained in this publication or as otherwise supplied to Users is
believed to be accurate and correct at time of going to press, and is given in
good faith, but it is for the User to satisfy itself of the suitability of the information
for its own particular purpose. GBHE gives no warranty as to the fitness of this
information for any particular purpose and any implied warranty or condition
(statutory or otherwise) is excluded except to the extent that exclusion is
prevented by law. GBHE will accept no liability resulting from reliance on this
information. Freedom under Patent, Copyright and Designs cannot be assumed.
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2. Process Engineering Guide:
Fluid Separation
CONTENTS Page
0
1
2
3
4
5
INTRODUCTION/PURPOSE
SCOPE
FIELD OF APPLICATION
DEFINITIONS
A SEPARATION LOGIC TREE
METHODS OF DISTILLATION
5.1 Fractional Distillation
5.2 Azeotropic Distillation
5.3 Extractive Distillation
3
3
3
3
3
4
4
7
8
6
LIQUID-LIQUID EXTRACTION
9
7
OTHER COMMERCIAL METHODS OF SEPARATION
11
7.1 Adsorption
7.2 Fractional Crystallization
7.3 Ion Exchange
7.4 Membrane Processes
7.4.1 Ultrafiltration
7.4.2 Reverse Osmosis
7.4.3 Pervaporation
7.4.4 Liquid Membranes
7.4.5 Gas Permeation
7.4.6 Dialysis
7.4.7 Electrodialysis
11
12
12
13
13
13
14
15
15
16
16
7.5 Supercritical Fluid Extraction
7.6 Dissociation Extraction
7.7 Foam Fractionation
7.8 Clathration
7.9 Chromatography
16
17
18
18
19
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3. 8
OTHER METHODS OF SEPARATION
8.1 Precipitation
8.2 Paper Chromatography
8.3 Ligand Specific Chromatography
8.4 Electrophoresis
8.5 Isoelectric Focusing
8.6 Thermal Diffusion
8.7 Sedimentation Ultracentrifugation
8.8 Isopycnic Ultracentrifugation
8.9 Molecular Distillation
8.10 Gel Filtration
19
19
19
19
19
20
20
20
20
20
20
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4. APPENDICES
A
AT A GLANCE CHART BASED ON FENSKE, UNDERWOOD
21
B
A GENERALIZED y - x DIAGRAM
22
C
TEMPERATURE - COMPOSITION DIAGRAMS FOR
AZEOTROPIC MIXTURES
23
A TYPICAL y - x DIAGRAM FOR EXTRACTIVE DISTILLATION
(SOLVENT FREE BASIS)
24
RAPID ESTIMATION OF LIQUID-LIQUID EXTRACTION
REQUIREMENTS
25
D
E
F
LIQUID - LIQUID EXTRACTION - THE USE OF EXTRACT
REFLUX
26
G
SELECTIVITIES REQUIRED FOR EQUAL PLANT COSTS
27
FIGURE
1
SEPARATION LOGIC TREE
DOCUMENTS REFERRED TO IN THIS PROCESS
ENGINEERING GUIDE
4
28
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5. 0 INTRODUCTION / PURPOSE
A beginner in the field of fluid separation can be overwhelmed by the apparent
wealth of choice available. In reality that choice is limited. This Engineering
Guide presents the options available with the intention of giving an overview of
methods of separation. Knowledge of the basic concepts is assumed.
1 SCOPE
This Engineering Guide describes each method of separation and outlines the
basic theory involved. For distillation and solvent extraction (the most widely
used fluid separation techniques) a short cut method of design is given. One or
two commercial processes for gas separation are arbitrarily included.
A conscious effort is made, however unapparent to the casual reader, to call on
experience to highlight important points and areas where caution should be
exercised. Where appropriate, the implication of the separation technique on the
total flowsheet is discussed.
A bibliography of further useful reading material is given at the end of each
Clause for the serious advocate.
This Engineering Guide does not cover the process engineering design of fluid
separation equipment.
2 FIELD OF APPLICATION
This Guide applies to the process engineering community in GBH Enterprises
worldwide.
3 DEFINITIONS
For the purposes of this Guide no specific definitions apply.
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6. 4 A SEPARATION LOGIC TREE
Based on an appreciation that simple is best and what is best understood usually
prevails, a separation logic tree can be proposed. This presents a stepwise
procedure for selecting the separation method most likely to be accepted and is
shown in Figure 1.
Realistically, if distillation can be used then this is the preferred technique; the
simpler the type of distillation the better. After distillation think of liquid-liquid
extraction. Any other method is specialized and should be considered with an
GBHE expert or the company offering the system.
The purist will maintain that the separation method chosen will depend on
feasibility and cost. However, a large monetary carrot is required to change from
a conventional, totally satisfactory, established technique to any other method.
Fractional distillation is favored because it is tried and trusted. It can be applied
over a wide range of conditions (i.e. where vapor and liquid co-exist) provided
that there is a difference in volatilities.
Azeotropic distillation, extractive distillation and liquid-liquid extraction are more
complex: another component is added to enhance the non-ideality of the mixture
to be separated. These methods are usually employed when classes of
components (e.g. paraffins from aromatics) have to be separated, or the system
is heat sensitive, or maybe the operating pressure for fractional distillation would
be very high or very low.
The other commercial methods of separation have often been developed for a
specific application. This has necessarily involved a large expenditure in
development time and money. Not unreasonably their propagators try to widen
their scope and applicability.
In line with the aforementioned, this document concerns itself mainly with
distillation in terms of how to reach the most appropriate system, with attention
also being given to liquid-liquid extraction. An outline of other methods of
separation, together with their general areas of applicability, is also given.
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7. 5 METHODS OF DISTILLATION
5.1.1 Fractional Distillation
Distillation involves the separation of the components of a liquid mixture by
partial vaporization of the mixture and separate recovery of vapor and residue.
To refresh memories relative volatility (a) is a direct measure of the ease of
separation by a distillation procedure. Using normal nomenclature for a binary
mixture A-B:
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8. where K = vapor-liquid equilibrium constant
x = liquid mole fraction
y = vapor mole fraction
and for ideal solutions:
where P° = vapor pressure of pure components
The closer the value of a is to unity the more difficult the separation. In a simple
system a knowledge of the boiling points shows whether the mixture would be
easily separable.
Boiling Point Difference
°C
2
5
10
20
30
50
100
Approximate
Relative Volatility
1.05
1.11
1.25
1.6
2.0
3.1
8.7
Knowing α, a feel for still requirements can be readily obtained using Fenske,
Underwood, Gilliland or for α = 1.2 to 2.0 by use of Appendix A. For the operating
optimum, remember to take Nmin x 2 (and Rmin x 1.3).
This approach can be adopted for mixtures containing more than two
components by using the key components concept.
These only apply strictly to ideal systems (i.e. relative volatility does not change
with composition, constant molal overflow). In practice many systems are nonideal. To allow for deviations from ideality in the liquid phase the concept of
activity coefficients was introduced, thus:
, where = ﻻactivity coefficient
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9. The majority of non-ideal systems (greater than 90%) exhibit positive deviations
from Raoult’s Law. Systems in which the components are strongly associated,
e.g. mixtures containing basic and acidic components, may exhibit negative
deviations. Qualitatively the differences displayed between ideal systems and
those exhibiting positive and negative deviations are apparent on
considering a generalized y-x diagram, see Appendix B.
The curves in Appendix B show that in non-ideal mixtures the greatest deviations
from ideal behavior occur at high dilution. In practice it will, for example, be more
difficult to obtain pure A, (the more volatile component) and easier to obtain pure
B (the less volatile component), for a system exhibiting positive deviations than
would be the case if the system behaved ideally. As on most occasions the
concern is to produce a pure tops product, care should be taken with the
design of columns embracing non-ideal systems. The Nmin requirement can often
be 1.5 to 2 times that calculated assuming ideal behavior, and on occasions very
much higher.
Vapor phase non-idealities can usually be neglected at atmospheric and subatmospheric pressures.
The aforementioned considers a single fractionation column, in real life multicomponent systems and separation trains have to be considered. In general
terms the distillation train should be designed to give the lowest total vapor boilup rate. Two rules of thumb are of help in sequencing columns to arrive at this
desired state of affairs, viz:
(a) Favor the scheme in which 25 to 50% of the feed is removed as distillate;
and, less importantly:
(b) Do difficult separations last.
In practice, another possibility which should be considered when addressing
multi-component systems is the suitability of including side-stream operation.
This is a very useful way of minimizing the total vapor rate required, and hence
saving capital and energy, providing a pure product is not required. Normally, if it
is more important to minimize heavy-ends content in the side stream product a
liquid side stream would be removed above the feed. If it is more desirable to
minimize light-ends in the side stream product a vapor (or liquid) side stream
would be removed below the feed.
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10. Another choice that has to be made is whether to use batch or continuous
fractionation columns. Separation by batch distillation is widely used, especially
in the Fine Chemicals area. Continuous distillation is the accepted operation in
the petrochemicals and other large tonnage areas. Batch operation is usually
confined to low rates of production (say, 3000 te/annum), where adjacent
processing stages are batch operation and where there is the need for
operational flexibility in a multi product unit.
Attention may have to be given to components undergoing chemical reaction
during the distillation operation. This can be allowed for if the reaction is an
intention of the process. Difficulties can occur if reaction occurs at fractionation
conditions and this likelihood was not recognized at the design stage. Other
system properties which may detract from the performance of distillation
columns are the deposition of solids or the tendency to foam. The addition of an
anti-foam agent may offer a solution to the latter problem, though it is usually
possible to design for a foaming system so that anti-foam is not needed.
Behavior such as foaming is often not evident or is difficult to recognize in a
laboratory or semi-technical simulation of the system.
Although not strictly within the scope of this Engineering Guide, absorption is a
technique widely used in separation trains. It is akin to distillation in that the
absorption column is similar to that used in distillation, although not usually
including a condenser or reboiler.
Absorption is the removal of one or more selected components from a mixture of
gases by absorption into a suitable liquid. The process is dependent on the
differential solubility of the gas phase components in the liquid. It is usually
necessary to remove the gas from the solvent by stripping in another column,
either by pressure swing and/or increasing temperature.
The following documentation may prove to be of further value:
(1) GBHE-PEG-MAS-607
(2) GBHE-PEG-MAS-601
(3) GBHE-PEG-MAS-603
(4) Distillation systems design procedure, GBHE Engineering Group.
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11. 5.1.2 Azeotropic Distillation
An azeotrope is a mixture of two or more liquid components which boils at
constant temperature and distils over completely without change of composition.
The ease of formation of a binary azeotrope is determined by:
(a) the magnitude of the deviations from Raoult’s Law;
and
(b) the difference in boiling points of the two components.
The smaller the difference in boiling points the smaller the deviations from
Raoult’s Law (i.e. from ideality) required for azeotrope formation.
Positive deviations from Raoult’s Law ( ,)1 > ﻻby far the most common, can give
rise to minimum boiling azeotropes. Negative deviations ( )1< ﻻcan result in the
formation of maximum boiling azeotropes. Azeotropes can be classified as
homogeneous (those which exist in one liquid phase and include minimum and
maximum boiling azeotropes) and heterogeneous (those which exist as
two liquid phases in equilibrium and are always minimum boiling).
Heterogeneous azeotropes are characterized by large positive deviations from
Raoult’s Law. Most azeotropic systems are of the minimum boiling type.
Typical temperature-composition diagrams are given in Appendix C. By
definition, Azeotropic systems are non-ideal and should from a design viewpoint
be treated with care. However, there is nothing mystical about these systems and
the azeotrope can in the most simple interpretation be considered as a pseudocomponent. For example, there may be a requirement to separate a
complex mixture, two of the components of which form an azeotrope. The
azeotrope may be a key component in the system. Considering the azeotrope as
a pseudo-component would allow Fenske-Underwood-Gilliland to be used. This
would at least be a safe approach giving an over design (although sometimes a
grossly over designed system). This approach can be significantly refined if
account is taken of the azeotrope composition (see reference asterisked!*).
The principal applications of azeotropic distillation, ie where an azeotropic agent
is added to the system, are:
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12. (1)
In the separation of close boiling components, where the azeotropic
agent forms a minimum boiling azeotrope with only one component,
or if it forms binary azeotropes with two of the components in the
system, one of the binary azeotropes boils sufficiently lower than
the other;
(2)
To facilitate separation of the two components in an already
existing binary azeotrope by formation of a ternary azeotrope. The
ternary azeotrope should boil sufficiently below any binary
azeotrope, and the ratio of the original components in the ternary
azeotrope should be different from their ratio before the azeotropic
agent was added.
The introduction of an azeotropic agent to facilitate separation often necessitates
additional equipment and as a result a more complex separation train. Thus, if an
ester is added to make the separation of water from acetic acid easier the
condensed overheads will split into two phases. The ester-rich phase will be
returned to the column as reflux. The water phase will contain solvent
ester which should be recovered in an additional distillation column.
Remember the composition of an azeotrope can be changed with increase or
decrease in pressure.
In general, the added azeotroping agent is best returned as reflux to the top of
the column, usually in about 30 to 50% excess over that required to form the
azeotrope.
The following documentation may prove to be of further value:
Swietoslawski, Azeotropy and Polyazeotropy, Pergamon Press, 1963.
Kirk-Othmer, Encyclopedia of Chemical Technology, Wiley-Interscience, 3rd
Edition, Vol 3, 352 (1978).
Horsley, For azeotropic data, see: Azeotropic Data -III, Amer Chem. Soc.,
Advances in Chemistry Series 116 (1973).
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13. 5.1.3 Extractive Distillation
Extractive distillation is based upon the addition of an extractive agent to a
mixture preferably containing two components of different chemical structure.
The added agent enhances the deviation from ideality or activity coefficient of
one component relative to the other, ie. it enhances the relative volatility. The
resulting difference in volatility permits fractionation which may not have
been economically attractive using fractional distillation. In some cases extractive
distillation is used where classes of components are to be separated (eg
paraffins from aromatics) where the boiling point spread could be such that
fractional distillation in one column would be impossible.
The extractive agent is chosen such that its volatility is low relative to those of the
feed components. The solvent is always introduced above the fresh feed stage in
order to maintain a high solvent concentration, which can be assumed to be
constant throughout most of the column. Usually in extractive distillation, 40 to 90
mole % solvent is required in the liquid phase to maximize the difference in
volatilities between the feed components. A typical y-x diagram, on a
solvent free basis, is given in Appendix D. Vapor-liquid equilibria data are
essential for design of an extractive distillation column.
Solvent is not fed to the top stage because a few plates should be provided
above the solvent entry point to reduce the concentration of solvent in the
overheads to an acceptable level. Feed is usually introduced to the column in
vapor form as liquid feed dilutes the descending solvent and reduces the solvent
concentration in the bottom section. Reflux at the top of the column also
dilutes the solvent, and increased reflux is not always synonymous with
increased separation.
In addition to being easily separable from the feed components the solvent
should be:
(a) Completely miscible with the top product under top plate conditions, ie the
solvent should not be too selective. The appearance of a second liquid
phase gives an unwanted decrease in relative volatility.
(b) Incapable of forming azeotropes with the feed components in the
extractive distillation zone.
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14. The extractive distillation system requires at least two columns - the main
extractive column and a second column to separate the extracted components
from the solvent. The overall separation train may be even more complex if
solvent has to be recovered from the overheads leaving the extractive column.
This may require a further distillation column or a water wash system.
Plate efficiency is often low in extractive distillation columns (25 to 35%).
The following documentation may prove to be of further value:
Perry, Chemical Engineers Handbook, 6th Edition, McGraw-Hill Book Company,
13-53 (1984).
6 LIQUID-LIQUID EXTRACTION
Liquid-liquid (or solvent) extraction involves the addition of an extractive solvent
to the mixture to be separated, the solvent being partially miscible with at least
one component, or class of components, in the mixture. The solvent is such that
it is selective toward one component, that is it enhances the deviation from
ideality or the activity coefficient of one component relative to another.
In general the solvent is required to have a selectivity factor β, greater than 2 and
a capacity or solubility for the component(s) to be extracted of not less than 10%.
Where
ﻻA, xA = mole fraction of component A in co-existing equilibrium
phases.
ﻻB, xB = mole fraction of component B in co-existing equilibrium
phases.
As β decreases, the number of extraction stages required for a given separation
increases; as capacity decreases, the amount of solvent required increases. In
practice, the choice of solvent is always a compromise, as β increases capacity
normally decreases. Solvent selection is a critical design step that depends on
the properties of the solutes to be recovered; there is no universally
applicable solvent. A common approach in solvent selection is to carry out a
literature survey of solvents used in similar applications. More erudite
approaches may be based on hydrogen bonding tendencies or the determination
of activity coefficients at infinite dilution by gas-liquid chromatography.
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15. In liquid-liquid extraction, the partition (or distribution) coefficient gives an
indication of the ease of separation. The partition coefficient is defined as:
where C is the concentration of solute in phase I and phase II, respectively.
Ideally, K is independent of the concentration of solute and of the ratio of the two
immiscible phases.
If the required separation cannot be achieved using one extraction stage the
generally favored mode of operation is in a counter-current system, where the
solvent and feed travel in opposite directions. For such a system Appendix E
allows a rapid means of estimating the number of theoretical extraction stages at
a given solvent to feed ratio to achieve a required separation.
However, even with an infinite number of stages the richest extract layer is that in
equilibrium with feed. As a rule the richer the feed in extractable components the
richer will be the equilibrium extract layer in these substances and the sharper
the separation. The shortcomings of liquid-liquid extraction without reflux are
therefore obvious, this applies particularly to a feed lean in extractable
components.
What cannot be achieved by increasing the number of stages can be
accomplished by means of reflux. In a feed lean in extractable components the
use of extract reflux would give a sharper separation. Extract reflux involves
returning part of the extract phase from which the solvent has been completely
removed (the solute) or partly removed. The concentration of solute in the extract
layer is then greater than that in equilibrium with the feed. For example, Appendix
F illustrates a solvent extraction process using a high boiling solvent for the
separation of aromatics from non-aromatics. Part of the aromatic extract phase is
returned to the extractor as reflux.
In extractors operating with reflux the feed enters an intermediate point in the
system. Reflux return should not give a completely miscible system. The use of
reflux results in an increased energy requirement.
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16. Three basic types of unit are available.
(a)
Mixer-settlers:
This is the name given to a type of extractor made up of a number of
mixing and settling chambers connected alternately in series. These are
normally only used when a few extraction stages are required. Scale up is
good and they have a good turn down ratio.
(b)
Packed and plate columns:
Probably the most widely used for simple systems requiring a small
number of stages and at low throughput. The system is good in that there
are no moving parts. Some caution should be exercised in the scale up
process.
(c)
Mechanically agitated columns:
As throughput and a larger number of stages becomes important,
mechanically agitated equipment should be used. A variety of proprietary
devices are available, including rotating disc contactors (RDC’s), the
Kuhni extractor etc. These systems offer a lower height per theoretical
extraction stage and also flexibility in terms of throughput and phase ratio.
In practice, liquid-liquid extraction is often used in conjunction with extractive
distillation; for example in the recovery of aromatics from hydrocarbon mixtures.
In this system the overheads from the extractive distillation column, consisting
mainly of light paraffins and naphthenes, are returned as reflux to the solvent
extraction column. They act as a backwash to remove heavier non-aromatics,
which would be more difficult to remove in the extractive distillation stage.
As in azeotropic and extractive distillation, the use of liquid-liquid extraction leads
to a more complex separation train. A distillation column is required to remove
the extracted components from the solvent. The raffinate may require water
washing to recover small amounts of solvent present. Quite often a further small
distillation column is required for clean up of a solvent purge.
Ideally, the system would use as solvent a component already present in the
process.
The presence of minor contaminants, in particular surfactants, can have a major
influence on the process. Before establishing final design a laboratory or semitechnical scale simulation should be carried out using the selected equipment,
actual process streams and at the proposed operating conditions.
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17. The following documentation may prove to be of further value:
Treybal, Liquid Extraction, McGraw-Hill, New York, 1963.
Reissinger, Schroeter, Modern Liquid-Liquid Extractors: Review and Selection
Criteria, I Chem E Symposium Series No 54.
The following Separation Processes Service reports (Harwell, Warren Spring):
SAR1 Liquid-liquid extraction, June 1974.
DR6 Selection of solvents for liquid-liquid extraction processes. Part 1 Organic
systems, October 1978.
An interesting paper of general applicability compares the selectivities in
fractional distillation, extractive distillation and solvent extraction which are
required to give equal plant cost. (Souders, Mott, Chem Eng Prog, 60, No 2, 75
(1964)).
Although published in 1964 the findings presented in Appendix G are still of
interest. The comparison assumes 67% solvent concentration and four times as
much liquid in extractive distillation and in solvent extraction as in fractional
distillation. Thus, for example, for the cost of separation to be the same the
relative volatility in fractional distillation would be 1.5, that in extractive distillation
2.0 and the selectivity factor for liquid-liquid extraction would be 6.0.
7 OTHER COMMERCIAL METHODS OF SEPARATION
The following sub clauses 7.1 to 7.9 (inclusive) outline other methods of
separation that have been used, or have obvious potential to be used,
commercially. They may be worth considering for specialized purposes. The
methods are not listed in any order of merit.
7.1 Adsorption
Adsorption is a physical phenomenon which occurs when gas or liquid molecules
are brought into contact with a solid surface. There are two main categories of
adsorption. The first type, and generally of primary interest, is known as physical
or van der Waals adsorption where the interaction between the solid and the
condensed molecule is relatively weak.
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18. In this process the equilibrium between solid and condensed molecule is
reversible and is rapidly attained when the temperature and pressure are
changed. The second type is called activated adsorption or chemisorption where
interaction is strong, the bonds formed being almost as strong as those in
chemical compounds. This type of adsorption is often irreversible.
Important adsorbents include activated carbon, aluminium oxide, silica gel and
molecular sieves. The latter are widely used in commercial applications.
Molecular sieves function as physical adsorbents, they are highly efficient, easily
regenerable, crystalline silica-aluminas. They can facilitate separation by two
mechanisms :
(a) conventional adsorption where the sieve shows a strong preference for
polar compounds, particularly water;
and
(b) separation by size where only those molecules able to migrate through the
sieve’s pore or window opening are retained. The pore size of a particular
molecular sieve can be controlled accurately within a small range of
molecular dimensions.
The adsorption process requires cyclic operation, adsorption being followed by
desorption to recover the adsorbed species. The length of operating cycle
determines the number of beds which should be used to allow continuous
operation. Desorption is usually the most inefficient step in the cycle and can be
accomplished by means of thermal swing, pressure swing, purge gas stripping or
displacement cycles.
Adsorption is a technique widely used to remove impurities from various process
streams, for example in drying, sweetening and color removing operations.
However, in the last quarter of a century, largely due to the availability of
synthetic molecular sieves, adsorption has become established for specific bulk
separations difficult to achieve by other means. In particular the separation of
normal paraffins from admixture with other hydrocarbons (the vapor phase IsoSiv
process and the liquid phase Molex process), the separation of p-xylene from
other C8 aromatics (the Parex process) and the recovery of hydrogen from
process gas streams.
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19. The following documentation may prove to be of further value:
Kirk-Othmer, Encyclopedia of Chemical Technology, Wiley-Interscience, 3rd
Edition, Vol 1, 531, 563 (1978).
Perry, Chemical Engineers Handbook, 6th Edition, McGraw-Hill Book Company,
16-5 (1984).
7.1.1 Fractional Crystallization
Crystallization processes make use of solid-liquid equilibria to effect a separation.
A liquid mixture cooled past its freezing point produces a solid phase, different in
composition from the mother liquor. Separating the two phases and remelting the
solid phase gives a purified product. Numerous types of solid-liquid equilibria are
known, the eutectic type is the most important industrially.
In a eutectic system, if the solid could be perfectly separated from the liquid
phase, 100% pure product could be produced in one stage. This is not achieved
in practice because of mother liquor adhering to the crystal surface, or held in the
crystal mass by surface tension and capillary forces, or being occluded in crystal
imperfections.
A conventional crystallization process would involve three stages:
(a) A crystallization stage where crystals are formed either in cooling tanks
with agitation for long periods or in scraped surface chillers.
(b) A separation stage, usually effected by centrifuges or filters.
(c) A purification stage.
Purification is usually carried out by using a wash liquor (chosen to be easily
separable from the required component) or by continuous countercurrent
treatment of the impure crystal mass with some of the melted crystal product (eg
the Phillips pulsed column).
Various continuous fractional crystallization devices have been proposed which
claim to produce high purity product in a single piece of equipment. Although
apparently proven on the laboratory and pilot plant scale they have not been
used on large tonnage commercial plant.
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20. Although heats of fusion are much lower than heats of vaporization,
crystallization is an expensive technique and its use is consequently limited. It is
applied where components having very close boiling points and similar chemical
structure (usually isomers) are to be separated.
The following documentation may prove to be of further value:
Kirk-Othmer, Encyclopedia of Chemical Technology, Wiley-Interscience, 3rd
Edition, Vol 7, 243 (1978).
Separation Processes Service report (Harwell, Warren Spring), SAR2
(Reviewed), Industrial crystallization, March 1986.
7.1.2 Ion Exchange
Ion exchange is exactly what the name implies, an exchange of one ion for
another. Ion exchange resins are insoluble electrolytes, consisting of a high
concentration of polar or functional groups incorporated in a synthetic, resinous
polymer. The polar groups may be acidic (cation exchange resins) or basic
(anion exchange resins).
The strongly acidic cation exchange resins contain, for example, the sulphonic
group -S03H; the weakly acidic resins contain the carboxyl group -COOH. The
latter only has a useful capacity in neutral or alkaline solutions. The strongly
basic anion exchange resins contain the quaternary ammonium group - NR+30H; the weakly basic resins contain amino (NH2), mono – and di-substituted amino
groups. The latter can only usefully be used in neutral or acid solutions.
Important factors which influence the rate and extent of an ion exchange process
are the nature of the resin and the molecular size, valency, and concentration of
the ions to be absorbed. Reduction in the particle size of the resin results in an
increased rate of exchange, consistent with a diffusion controlled process.
Ion exchange allows the removal of one or more ionic species from a liquid
phase by means of an exchange, or transfer, for another ion. This transfer may
be required to purify or modify the liquid phase, to concentrate, isolate and/or
purify one or more of the ionic components, or to separate mixed ionic species
into two or more fractions. The use of ion exchange resins for water treatment
is widely recognized. Provided ions are present ion exchange processes can be
carried out in aqueous-organic systems and in non-aqueous solvents.
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21. The following documentation may prove to be of further value:
Schweitzer, Handbook of Separation Techniques for Chemical Engineers,
McGraw-Hill Book Company, 1979.
Li (Editor), Recent Advances in Separation Techniques -II, A.I.Ch.E Symposium
Series, Vol 76, No 192, 60 (1980).
7.4
Membrane Processes
The use of membrane separation processes has been mooted for some
considerable time. Advances have been made in some areas (noticeably gas
separation) but wider application still awaits the development of membranes
capable of giving high throughputs at high selectivities, whilst maintaining good
chemical and physical stability.
7.4.1 Ultrafiltration
Molecular filtration or ultrafiltration involves a sieving mechanism. The solvent
permeates the membrane by Poiseuille type flow down microcapillaries within the
membrane, and solute molecules are rejected because they are larger than the
pores through which the solvent molecules can pass.
Ultrafiltration can reject materials of molecular weight down to about 500. A
range of membranes is available with molecular weight retentions from 500 to
300,000. Because of the high molecular weights osmotic pressures are low and
operating pressures of only 5 to 60 psi g are required.
In general, this technique is excellent for concentration and may also be used to
separate two solutes (one able to pass through, the other held back by the
appropriate membrane). The major problem with ultrafiltration is membrane
fouling.
Ultrafiltration is widely used commercially. For example, in biological applications,
in the food industry (dewatering), the dairy product industry (cheese whey
treatment), the pharmaceutical industry (concentration and separation on
molecular weight basis) and in the purification and recovery of electrophoretic
paints.
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22. 7.4.2 Reverse Osmosis
Osmosis occurs whenever a solution is separated from its solvent, or from a
more dilute solution, by a membrane and is the phenomenon of spontaneous
flow of solvent through the membrane and into the more concentrated solution. In
osmosis the membrane is normally considered to be semipermeable, that is it
allows the passage of solvent but not the solute. The osmotic pressure of a
solution is that pressure which has to be applied to the solution to stop the
osmotic flow of solvent.
Application of a hydrostatic pressure in excess of the osmotic pressure results in
flow of solvent from the solution into the pure solvent. This process is called
reverse osmosis (and on occasions hyperfiltration).
Transport of material through membranes under reverse osmosis conditions is
via a sorption diffusion process. The criterion for solubility is that like dissolves
like. Rejection of solute occurs largely because of its low solubility in the
membrane. Thus, it is the chemical similarity between diffusing species and
membrane that determine the direction of separation. The rate of permeation
is inversely proportional to the membrane thickness and is directly proportional to
the difference between applied and osmotic pressure. As pressure has little
effect on the solute rate, selectivity appears to improve as the applied pressure is
increased. The process is usually operated at 400 to 600 psi (25 to 40 bar)
pressure.
Reverse osmosis is used commercially for desalination and for brackish water
treatment (75% to 85% treated water recovery is normal in the latter). Salt
rejection is high at 95 to 99% in water treatment. However, selectivity factors for,
say, isopropanol-water separation using a cellulose acetate membrane under
reverse osmosis conditions tumble to less than 2. In practice, there is
still not a suitable membrane for the separation of low molecular weight organic
mixtures. The technique is used by Organics Division for the concentration of
Procion T-dyes.
In the long term this technique may be developed such that it will find application
in:
(a) Removing the bulk of a material away from trace impurities which may
have unwanted effects, eg odor, color.
(b) Removing solvent from a homogeneous catalyst stream to allow catalyst
recycle.
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23. (c) Processing industrial aqueous effluents to renovate the water.
7.4.3 Pervaporation
In the pervaporation process a liquid mixture is brought into contact with one side
of a polymeric film, the downstream side being maintained at a low pressure.
Separation is affected if one component permeates through the membrane at a
relatively faster rate. The temperature at which the process can be operated is
limited by the nature of the membrane material. It is preferred to heat the liquid
feed mixture to increase the vapor pressure and thus the rate of permeation. The
permeate is removed as a vapor.
A variation on this technique is Perstraction in which the permeate is dissolved
and carried away in a fluid diluent which does not interact with the membrane.
Like reverse osmosis the transport mechanism in pervaporation is a sorptiondiffusion process.
Very simply it proceeds via:
(a) Solution of the permeating molecules in the membrane;
(b) Diffusion through the membrane;
(c) Evaporation from the downstream surface of the membrane.
Selectivity is, therefore, due principally to preferential sorption. The rate of
permeation is inversely proportional to membrane thickness and is also
dependent on temperature. Pervaporation can be considered complementary to
reverse osmosis in that it is best suited to permeation of the component present
at low levels in a mixture rather than the major component, as in reverse
osmosis.
The use of pervaporation has been proposed for more than a quarter of a century
and small, 6m3/day, commercial units are now in operation. The main reported
usages of pervaporation are in the dehydration of alcohols, ketones and ethers.
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24. 7.4.4 Liquid Membranes
A liquid membrane, or more accurately a liquid surfactant membrane, is a film
formed at an oil-water interface by a surfactant solution. Such films are formed by
dispersing the solution to be separated in the form of very small droplets in a
surfactant solution. The droplets covered with liquid membrane are then
contacted with an organic solvent. One of the components of the mixture
permeates through the liquid membrane at a faster rate than the other. The
solvent therefore becomes richer in this component whilst the droplets become
richer in the less permeable component. To increase drop stability and
permeation rate the drop diameter is normally reduced by emulsifying the feed in
the surfactant solution. The emulsion is then mixed with the solvent which is the
continuous phase.
Separation is achieved by selective diffusion of one component through the liquid
membrane into the liquid of lower concentration. Once separation is effected, the
three phases can be separated by first settling the emulsion and continuous
phase and then breaking the emulsion.
Liquid membranes are purported to have several advantages over solid
polymeric membranes. They do not have pin holes, do not have to be replaced or
repaired and require no mechanical support. However, as yet, there is no
commercial exploitation of this technique. This is also true for the proposed
supported liquid membrane configuration. In this system the liquid membrane is
incorporated within an inert microporous support. Possible applications may be
found in:
(a) Separation of species which are chemically different;
(b) Recovery of products from low conversion processes by permeation of
components present in least amount;
(c) Removal of trace impurities, especially in waste water treatment.
7.4.5 Gas Permeation
One area in which membrane processes are competitive at the present time is in
the separation of gases. The most widely reported use is that of the Monsanto
Prism separator for hydrogen purification. High pressure feed gas is supplied to
one side of the membrane. Permeate accumulates on the membrane low
pressure side.
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25. Again mechanisms describing gas transport generally involve solubilization and
diffusion. The diffusion rate depends on the size of the gas molecule and the gas
solubility in the polymer, with gas partial pressure as the mass transfer driving
force.
For the Monsanto system where the active membrane is a polysulfone, the
following is a list of 'fast’ and ’slow’ permeating gases:
Fast gas
Hydrogen
Helium
Hydrogen sulfide
Carbon dioxide
Water vapor
Slow gas
Oxygen
Methane, ethane etc
Carbon monoxide
Nitrogen
Ethylene, propylene etc
In general, gas separation processes are good for enriching; say from 50% to
90%. The feed pressure should be greater than 150 psi (10 bar) and temperature
in the range 10 to 50°C. They are not so good for obtaining a high purity product,
say 99%, or at feed pressures below 150 psi (10 bar) and temperatures greater
than 100°C. The polysulfone membrane is susceptible to certain aggressive
gases, eg, methanol, ammonia, acid gases and aromatics.
Gas permeation for hydrogen purification applications has successfully competed
with established processes - cryogenics, pressure swing adsorption. The latter
still has the edge where pure hydrogen is required. With industry gaining
confidence from the commercial ventures, gas permeation technology could
develop rapidly and other separations may become a reality on the large scale.
7.4.6 Dialysis
Dialysis involves the use of a membrane which selectively separates the solutes
in a solution by allowing the low molecular weight solutes to permeate through
the membrane into the pure solvent. The membrane restricts the passage of high
molecular weight solutes. At the same time, solvent will diffuse by osmosis in the
opposite direction. By periodically replacing the fresh solvent, complete
extraction of the diffusing solute can be achieved.
Concentration gradients provide the driving force and the nature of the
membrane establishes the selectivity in this diffusion process. The type of
membrane determines whether dialysis, a two way flow, or osmosis, flow of
solvent only into the concentrated solution, occurs.
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26. The most widely known use of dialysis is in artificial kidney machines. The
relative slowness of the dialysis process gives it little scope for industrial usage.
7.4.7 Electrodialysis
Electrodialysis involves the transport of ionic species across a permselective
membrane under the driving force of an electric gradient. Normally alternating
anion and cation selective membranes are used. This allows the separation of
ionic substances present in the feed stream.
The largest commercial application for electrodialysis is in the treatment of
brackish water to produce a potable water and in desalination generally. It is
more economic than reverse osmosis at high salt concentrations. It is also used
in the dairy and pharmaceutical industries.
The following documentation may prove to be of further value:
Torrey, Membrane and Ultrafiltration Technology, Noyes Data Corporation, 1984.
Hwang, Kammermeyer, Membranes in Separation, Vol VII, Techniques of
Chemistry, Wiley and Sons, 1984.
7.5
Supercritical Fluid Extraction
Supercritical fluid extraction refers to the use of fluids which are gases at ambient
temperature and pressure, but which become good solvents when compressed
to supercritical fluids (at pressures above the critical pressure). The supercritical
fluid region is loosely defined as being in the range of reduced temperatures
(actual temperature divided by critical temperature) of 0.9<Tr<1.4, and
reduced pressures of 1.0<Pr<5.0.
The properties of a supercritical fluid are between those of a liquid and a gas.
Fluids possess high solubilities similar to liquid solvents because of high
densities (specific gravities of 0.2 to 0.9). Viscosities and diffusivities of fluids are
intermediate to those properties for liquids and gases, this enables highly
efficient penetration and rapid mass transfer compared to liquid solvents. In the
supercritical fluid region relatively small changes in temperature and pressure
produce large changes in density and hence in solvent power.
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27. Carbon dioxide has been widely used as a supercritical fluid extractant as it is
non-toxic, nonflammable, inexpensive and has a conveniently low critical
temperature of 31°C. Other gases, or combination of gases, can be used
depending on the extraction requirement.
Supercritical fluid extraction is similar to liquid-liquid extraction and can be carried
out using a countercurrent extraction system. The highly volatile solvent can be
recovered by letting down the pressure and/or by distillation before
recompressing and returning to the extraction system. The process requires
capital-intensive, high pressure equipment which should be evaluated against
any potential energy savings.
Probably the two most quoted commercial applications of supercritical fluid
extraction are:
(a) The Residual Oil Supercritical Extraction (ROSE) process used for
deasphalting oil residues with pentane in the 1950’s;
And
(b) The decaffeination of green coffee beans using carbon dioxide introduced
in the late seventies.
Other uses have been claimed including the separation of organic chemicals
from water, oils from natural products and in polymer processing.
The following documentation may prove to be of further value:
Separation Processes Service report (Harwell, Warren Spring), SAR48,
Supercritical extraction and other high pressure extraction processes, September
1983.
Paulaitis et al, MIT Industrial Liaison Program, Report 9-33-82, Supercritical Fluid
Extraction, April 1982.
7.6
Dissociation Extraction
Dissociation extraction exploits the differences in the dissociation constants of
the components of a mixture in order to effect a separation.
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28. Typically, if a mixture of two weak organic bases (differing in their dissociation
constants) in an organic solvent is contacted with an aqueous phase containing a
stoichiometric deficiency of a strong acid, relative to the bases, then the bases
will compete for the available acid. The stronger base, ie that with the higher
dissociation constant, will react preferentially with the strong acid forming a salt in
the aqueous phase. The weaker base will be consequently enriched in the
organic phase. Products of high purity can be obtained if a multi-stage countercurrent process is adopted, as in liquid-liquid extraction. A mixture of weak acids
can be separated in similar fashion using a strong base.
This separation technique has been used to separate isomeric mixtures which
could not be practically achieved using distillation or crystallization methods.
Such isomers often exhibit considerable differences in their dissociation
constants, eg 3- and 4-picoline and meta- and paracresol.
The following documentation may prove to be of further value:
Hanson (Editor), Recent Advances in Liquid-Liquid Extraction, Pergamon, New
York, Chapter 4 (1971).
7.7
Foam Fractionation
Foam fractionation is dependent on the preferential concentration at the liquidgas interface of a naturally surface-active molecule. This species can be
separated from the bulk simply by providing sufficient interface and collecting the
resultant foam. A surface-inactive material can be removed by complex formation
with a suitable surfactant.
Separation at the normal air-water foam interface is affected by numerous factors
including:
(a) Concentration of the surfactant.
(b) pH.
(c) Temperature.
(d) Viscosity.
(e) Flow rates.
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29. (f) Bubble size etc.
Foam fractionation is particularly useful when the concentration of the material to
be removed is low. The technique has been considered for the removal/recovery
of detergents, alcohols and phenol from waste water streams.
The following documentation may prove to be of further value:
Schweitzer, Handbook of Separation Techniques for Chemical Engineers,
McGraw-Hill Book Company, 1979.
7.8
Clathration
Clathrates (or adducts) are inclusion or cage-like compounds which can be
considered as organic molecular sieves. Organic clathrates can trap other
molecules in the cavities of their regular geometric structure. The resultant
crystalline molecular complex is stable although normal chemical bonding is not
present. The formation and dissociation of the complex can therefore be
achieved with small changes in temperature and pressure.
Different types of clathration agents have been identified. They exist in several
forms ranging from spherical cavities, layer complexes, crystals with
interconnecting chambers and tubular structures.
The ability of clathrates to separate molecules on the basis of their shape has
been used commercially. Urea adducts were used to separate normal from
branched-chain paraffins. This separation is now carried out using synthetic
zeolites (inorganic molecular sieves) which afford a cleaner, simpler to operate
total system.
The following documentation may prove to be of further value:
Bhatnagar, Clathrate Compounds, Chand and Company (1968).
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30. 7.9
Chromatography
Separations by chromatographic methods depend upon the different attraction
which two alternative phases have for the components in a feed mixture. The two
phases can be gas-solid, liquid-solid, liquid-liquid or gas-liquid. The latter is the
system commonly used in analytical applications.
In gas-liquid chromatography the mixture to be separated is vaporized and
passed together with a continuous stream of nitrogen or other inert gas through
the column. The column is packed with a solid impregnated with a non-volatile
liquid. The stronger the attraction between this stationary liquid phase and the
feed components, the more slowly is a given component swept through the
column by the inert gas (or carrier gas). The mixture therefore separates into
pure components as discrete bands within the column. These bands are eluted
from the column by the carrier gas.
Although widely used in the laboratory for analytical and preparative purposes,
chromatography has found limited commercial application. This is largely due to
the difficulty of obtaining good resolution in large diameter columns. The use of
chromatographic techniques on an industrial scale has been proposed for the
separation of close boiling mixtures (particularly isomers), the fractionation of
natural products and the purification of pharmaceutical intermediates and
products.
The following documentation may prove to be of further value:
Schupp, Gas Chromatography, Technique of Organic Chemistry, Vol XIII,
Interscience Publishers (1968).
8 OTHER METHODS OF SEPARATION
The details contained in sub clauses 8.1 to 8.10 (inclusive) are included more for
completeness than practical usefulness. Some of the methods mentioned are,
and are likely to remain, laboratory oddities. Others have extremely limited usage
and are not strictly within the scope of this Engineering Guide.
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31. 8.1.1 Precipitation
A chemical reactant is added to a liquid mixture and reacts with one of the
components to form an insoluble precipitate.
8.1.2 Paper Chromatography
A liquid mixture is separated by differences in solubilities and adsorption
potentials on paper (or gel phase).
8.1.3 Ligand Specific Chromatography
A liquid mixture is contacted with an immobilized ligand which forms a reversible
chemical interaction with one of the components.
8.4
Electrophoresis
An electrical potential applied to colloidal systems dispersed in buffered solutions
in a cell causes the colloidal particles to migrate toward the electrodes according
to their charge.
8.5
Isoelectric Focusing
Carrier ampholyte mixtures are electrophoresed to establish a stable pH
gradient. The amphoteric macromolecules eg proteins, to be separated migrate
until they reach their isoelectric point; the pH at which the positive and negative
charges balance. The separation is therefore on the basis of composition rather
than size.
8.6
Thermal Diffusion
Components of a homogeneous solution (gas or liquid) are separated by means
of a temperature gradient. In a gas mixture the heavier molecules concentrate in
the cold region, in liquids molecular shape determines the separation.
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32. 8.7
Sedimentation Ultracentrifugation
The use of centrifuges rotated at high speeds that cause the rapid sedimentation
of macromolecules and allow, for example, the separation of large polymeric
substances according to molecular weight.
8.8
Isopycnic Ultracentrifugation
Biological substances are separated in high rotation centrifuges in which a
density gradient has been established. Use of the proper gradient material allows
particulates to be banded together isopycnically in the density gradient.
8.9
Molecular Distillation
In molecular distillation, the distance between evaporating and condensing
surfaces is less than the mean free path of the molecules involved at the
pressure used, normally high vacuum.
8.10 Gel Filtration
The separation of components is effected by the difference in their molecular size
and hence their ability to penetrate a swollen gel matrix.
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33. Refinery Process Stream Purification Refinery Process Catalysts Troubleshooting Refinery Process Catalyst Start-Up / Shutdown
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34. Refinery Process Stream Purification Refinery Process Catalysts Troubleshooting Refinery Process Catalyst Start-Up / Shutdown
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35. Refinery Process Stream Purification Refinery Process Catalysts Troubleshooting Refinery Process Catalyst Start-Up / Shutdown
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36. Refinery Process Stream Purification Refinery Process Catalysts Troubleshooting Refinery Process Catalyst Start-Up / Shutdown
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37. Refinery Process Stream Purification Refinery Process Catalysts Troubleshooting Refinery Process Catalyst Start-Up / Shutdown
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38. Refinery Process Stream Purification Refinery Process Catalysts Troubleshooting Refinery Process Catalyst Start-Up / Shutdown
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39. Refinery Process Stream Purification Refinery Process Catalysts Troubleshooting Refinery Process Catalyst Start-Up / Shutdown
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40. DOCUMENTS REFERRED TO IN THIS PROCESS ENGINEERING GUIDE
This Process Engineering Guide makes reference to the following documents:
ENGINEERING GUIDES
GBHE-PEG-MAS-601 VLE Data : Selection and Use (referred to in 5.1)
GBHE-PEG-MAS-603 Shortcut Methods of Distillation Design (referred to in 5.1)
GBHE-PEG-MAS-607 Batch Distillation (referred to in 5.1)
.
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