Chemical Process Engineering Volume 1
Description
Written by two of the most prolific and respected chemical engineers in the world, this groundbreaking two-volume set is the 'new standard' in the industry, offering engineers and students alike the most up-do-date, comprehensive, and state-of-the-art coverage of processes and best practices in the field today.
This first new volume in a two-volume set explores and describes integrating new tools for engineering education and practice for better utilization of the existing knowledge on process design. Useful not only for students, professors, scientists and practitioners, especially process, chemical, mechanical and metallurgical engineers, it is also a valuable reference for other engineers, consultants, technicians and scientists concerned about various aspects of industrial design.
The text can be considered as a complementary text to process design for senior and graduate students as well as a hands-on reference work or refresher for engineers at entry level. The contents of the book can also be taught in intensive workshops in the oil, gas, petrochemical, biochemical and process industries.
The book provides a detailed description and hands-on experience on process design in chemical engineering, and it is an integrated text that focuses on practical design with new tools, such as Excel spreadsheets and UniSim simulation software.
Written by two industry and university's most trustworthy and well-known authors, this book is the new standard in chemical, biochemical, pharmaceutical, petrochemical and petroleum refining. Covering design, analysis, simulation, integration, and, perhaps most importantly, the practical application of Microsoft Excel-UniSim software, this is the most comprehensive and up-to-date coverage of all of the latest developments in the industry. It is a must-have for any engineer or student's library.
A. Kayode Coker, PhD, is an engineering consultant for AKC Technology, an honorary research fellow at the University of Wolverhampton, UK, a former engineering coordinator at Saudi Aramco Shell Refinery Company, and chairman of the Department of Chemical Engineering Technology at Jubail Industrial College, Saudi Arabia. He has been a chartered chemical engineer for more than 30 years. He is a fellow of the Institution of Chemical Engineers, UK, and a senior member of the American Institute of Chemical Engineers. He holds a BSc honors degree in chemical engineering, a master of science degree in process analysis and development and PhD in chemical engineering, all from Aston University, Birmingham, UK, and a Teacher's Certificate in Education at the University of London, UK. He has directed and conducted short courses extensively throughout the world and has been a lecturer at the university level. His articles have been published in several international journals. He is an author of seven books in chemical engineering, a contributor to the Encyclopedia of Chemical Processing and Design, Vol 61 and a certified train-the-mentor trainer. He is also a technical report assessor and interviewer for chartered chemical engineers (IChemE) in the U.K. He is a member of the International Biographical Centre in Cambridge, UK, is in 'Leading Engineers of the World for 2008.' He is also a member of 'International Who's Who of ProfessionalsTM' and 'Madison Who's Who in the U.S.'
Rahmat Sotudeh-Gharebaagh, PhD, is a full professor of chemical engineering at the University of Tehran. He teaches process modeling and simulation, transport phenomena, plant design and economics and soft skills. His research interests include computer-aided process design and simulation, fluidization, and engineering education. He holds a BEng degree in chemical engineering from Iran's Sharif University of Technology, plus a MSc and a PhD in fluidization engineering from Canada's Polytechnique. He has been an invited Professor at Qatar University and Polytechnique de Montréal. Professor Sotudeh has more than 300 publications in major international journals and conferences, plus four books and four book chapters. He is the co-founder and editor-in-chief of the journal, Chemical Product and Process Modeling, a member of the Iranian Elite Foundation, and an official expert (OE) on the oil industry with the Iranian Official Expert Organization.
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A. Kayode Coker, PhD, is an engineering consultant for AKC Technology, an honorary research fellow at the University of Wolverhampton, UK, a former engineering coordinator at Saudi Aramco Shell Refinery Company, and chairman of the Department of Chemical Engineering Technology at Jubail Industrial College, Saudi Arabia. He has been a chartered chemical engineer for more than 30 years. He is a fellow of the Institution of Chemical Engineers, UK, and a senior member of the American Institute of Chemical Engineers. He holds a BSc honors degree in chemical engineering, a master of science degree in process analysis and development and PhD in chemical engineering, all from Aston University, Birmingham, UK, and a Teacher's Certificate in Education at the University of London, UK. He has directed and conducted short courses extensively throughout the world and has been a lecturer at the university level. His articles have been published in several international journals. He is an author of seven books in chemical engineering, a contributor to the Encyclopedia of Chemical Processing and Design, Vol 61 and a certified train-the-mentor trainer. He is also a technical report assessor and interviewer for chartered chemical engineers (IChemE) in the U.K. He is a member of the International Biographical Centre in Cambridge, UK, is in "Leading Engineers of the World for 2008." He is also a member of "International Who's Who of ProfessionalsTM" and "Madison Who's Who in the U.S."
Rahmat Sotudeh-Gharebaagh, PhD, is a full professor of chemical engineering at the University of Tehran. He teaches process modeling and simulation, transport phenomena, plant design and economics and soft skills. His research interests include computer-aided process design and simulation, fluidization, and engineering education. He holds a BEng degree in chemical engineering from Iran's Sharif University of Technology, plus a MSc and a PhD in fluidization engineering from Canada's Polytechnique. He has been an invited Professor at Qatar University and Polytechnique de Montréal. Professor Sotudeh has more than 300 publications in major international journals and conferences, plus four books and four book chapters. He is the co-founder and editor-in-chief of the journal, Chemical Product and Process Modeling, a member of the Iranian Elite Foundation, and an official expert (OE) on the oil industry with the Iranian Official Expert Organization.
Content
Preface xvii
Acknowledgments xix
About the Authors xxi
1 Computations with Excel Spreadsheet-UniSim Design Simulation 1
Section I - Numerical Analysis 1
Introduction 1
Excel Spreadsheet 1
Functions 2
Trendline Coefficients 2
Goal Seek 5
Solver 6
Linear Regression 7
Measuring Regression Quality 9
Multiple Regression 9
Polynomial Regression 11
Simultaneous Linear Equations 11
Nonlinear Equations 12
Interpolations 13
Integrations 14
The Trapezoidal Rule 14
Simpson's 1/3 Rule 15
Simpson's 3/8 Rule 15
Differential Equations 15
Nth Order Ordinary Differential Equations 15
Solution of First-Order Ordinary Differential Equations 15
Runge-Kutta Methods 16
Examples and Solutions 17
Section II - Process Simulation 28
Introduction 28
Thermodynamics for Process Simulators 29
UNISIM Design Software 30
Examples and Solutions 31
References 78
2 Physical Property of Pure Components and Mixtures 81
Pure Components 81
Density of Liquid 82
Viscosity of Liquid 83
Heat Capacity of Liquid 85
Thermal Conductivity of Liquid 87
Volumetric Expansion Rate 90
Vapor Pressure 91
Viscosity of Gas 93
Thermal Conductivity of Gas 94
Heat Capacity of Gases 95
Mixtures 97
Surface Tensions 98
Viscosity of Gas Mixture 99
Enthalpy of Formation 101
Enthalpy of Vaporization 103
Gibbs Energy of Reaction 105
Henry's Law Constant for Gases in Water 107
Coefficient of Thermal Expansion of Liquid 108
Diffusion Coefficients 109
Gas-Phase Diffusion Coefficients 109
Liquid-Phase Diffusion Coefficients 110
Compressibility Z-factor 111
Solubility and Adsorption 116
Solubility of Hydrocarbons in Water 116
Solubility of Gases in Water 117
Solubility of Sulfur and Nitrogen Compounds in Water 118
Adsorption on Activated Carbon 119
References 119
3 Fluid Flow 121
Introduction 121
Flow of Fluids in Pipes 121
Equivalent Length of Various Fittings and Valves 123
Excess Head Loss 123
Pipe Reduction and Enlargement 124
Pressure Drop Calculations for Single-phase Incompressible Fluids 124
Friction Factor 127
Overall Pressure Drop 128
Nomenclature 130
Compressible Fluid Flow in Pipes 130
Maximum Flow and Pressure Drop 131
Critical or Sonic Flow and the Mach Number 131
Mach Number 132
Mathematical Model of Compressible Isothermal Flow 134
Flow Rate Through Pipeline 136
Pipeline Pressure Drop 138
Nomenclature 139
Subscripts 139
Two-phase Flow in Process Piping 139
Flow Patterns 140
Flow Regimes 142
Pressure Drop 142
Erosion-Corrosion 145
Nomenclature 145
Vapor-liquid Two-phase Vertical Downflow 146
The Equations 147
The Algorithm 147
Nomenclature 147
Line Sizes for Flashing Steam Condensate 148
The Equations 148
Nomenclature 149
Flow Through Packed Beds 150
The Equations 151
Nomenclature 152
Examples and Solutions 152
References 162
4 Equipment Sizing 165
Introduction 165
Sizing of Vertical and Horizontal Separators 166
Vertical Separators 166
Calculation Method for a Vertical Drum 168
Calculation Method for a Horizontal Drum 170
Liquid Holdup and Vapor Space Disengagement 171
Wire Mesh Pad 171
Standards for Horizontal Separators 172
Piping Requirements 172
Nomenclature 172
Sizing of Partly Filled Vessels and Tanks 173
The Equations 173
Nomenclature 175
Preliminary Vessel Design 176
Nomenclature 177
Cyclone Design 178
Introduction 178
Cyclone Design Procedure 178
The Equations 179
Saltation Velocity 180
Pressure Drop 181
Troubleshooting Cyclone Maloperations 182
Cyclone Collection Efficiency 182
Cyclone Design Factor 182
Cyclone Design Procedure 183
Nomenclature 183
Gas Dryer Design 184
The Equations 186
Pressure Drop 187
Desiccant Reactivation 188
Nomenclature 188
Examples and Solutions 189
References 194
5 Instrument Sizing 195
Introduction 195
Variable-Head Meters 195
Macroscopic Mechanical Energy Balance 196
Variable-Head Meters 196
Orifice Sizing for Liquid and Gas Flows 200
Orifice Sizing for Liquid Flows 201
Orifice Sizing for Gas Flows 202
Orifice Sizing for Liquid Flow 204
Orifice Sizing for Gas Flow 204
Types of Restriction Orifice Plates 205
Case Study 1 205
Nomenclature 212
Control Valve Sizing 221
Introduction 221
Control Valve Characteristics 223
Pressure Drop for Sizing 224
Choked Flow 224
Flashing and Cavitation 224
Control Valve Sizing for Liquid, Gas, Steam and Two-Phase Flows 225
Liquid Sizing 226
Gas Sizing 227
Critical Condition 227
Steam Sizing 227
Two-Phase Flow 228
Installation 229
Noise 229
Control Valve Sizing Criteria 230
Valve Sizing Criteria 230
Self-Acting Regulators 231
Types of Self-Acting Regulators 231
Case Study 2 233
Rules of Thumb 246
Nomenclature 246
References 247
6 Pumps and Compressors Sizing 249
Pumps 249
Introduction 249
Pumping of Liquids 249
Pump Design Standardization 252
Basic Parts of a Centrifugal Pump 253
Impellers 253
Casing 253
Shaft 254
Centrifugal Pump Selection 255
Single-Stage (Single Impeller) Pumps 256
Hydraulic Characteristics for Centrifugal Pumps 260
Friction Losses Due to Flow 269
Velocity Head 269
Friction 271
Net Positive Suction Head (npsh) and Pump Suction 271
General Suction System 277
Reductions in NPSHR 279
Corrections to NPSHR for Hot Liquid Hydrocarbons and Water 279
Charting NPSHR Values of Pumps 280
Net Positive Suction Head (NPSH) 280
Specific Speed 282
"Type Specific Speed" 285
Rotative Speed 286
Pumping Systems and Performance 286
System Head Using Two Different Pipe Sizes in Same Line 288
Power Requirements for Pumping Through Process Lines 291
Hydraulic Power 292
Relations Between Head, Horsepower, Capacity, Speed 293
Brake Horsepower (BHP) Input at Pump 293
Affinity Laws 296
Pump Parameters 298
Specific Speed, Flowrate and Power Required by a Pump 299
Pump Sizing of Gas-Oil 301
Debutanizer Unit 303
Centrifugal Pump Efficiency 306
Centrifugal Pump Specifications 311
Pump Specifications 311
Steps in Pump Sizing 312
Reciprocating Pumps 313
Significant Features in Reciprocating Pump Arrangements 314
Application 316
Performance 316
Discharge Flow Patterns 317
Horsepower 318
Pump Selection 318
Selection Rules-of-Thumb 318
A Case Study 321
Pump Simulation on a PFD 321
Variables Descriptions 322
Simulation Algorithm 322
Problem 323
Discussion 324
Pump Cavitation 332
Factors in Pump Selection 333
Compressors 334
Introduction 334
General Application Guide 334
Specification Guides 337
General Considerations for Any Type of Compressor Flow Conditions 337
Fluid Properties 338
Compressibility 338
Corrosive Nature 338
Moisture 339
Special Conditions 339
Specification Sheet 339
Performance Considerations 339
Cooling Water to Cylinder Jackets 339
Heat Rejected to Water 339
Drivers 340
Ideal Pressure - Volume Relationship 341
Actual Compressor Diagram 343
Deviations From Ideal Gas Laws: Compressibility 343
Adiabatic Calculations 346
Charles' Law at Constant Pressure 346
Amonton's Law at Constant Volume 346
Combined Boyle's and Charles' Laws 346
Entropy Balance Method 347
Isentropic Exponent Method 347
Compression Ratio 354
Horsepower 356
Single Stage 356
Theoretical Hp 356
Actual Brake Horsepower, Bhp 356
Actual Brake Horsepower, Bhp (Alternate Correction for Compressibility) 361
Temperature Rise - Adiabatic 363
Temperature Rise - Polytropic 365
A Case Study Using Unisim Design R460.1 Software for a Two-stage Compression 365
Case Study 2 365
Solution 365
1. Starting UniSim Design Software 366
2. Creating a New Simulation 366
Saving the Simulation 367
3. Adding Components to the Simulation 367
4. Selecting a Fluids Package 368
5. Select the Units for the Simulation 369
6. Enter Simulation Environment 369
Accidentally Closing the PFD 371
Object Palette 371
7. Adding Material Streams 371
8. Specifying Material Streams 372
9. Adding A Compressor 374
Specifications 381
Compression Process 385
Adiabatic 385
Isothermal 385
Polytropic 385
Efficiency 388
Head 390
Adiabatic Head Developed Per Single-stage Wheel 390
Polytropic Head 391
Polytropic 391
Brake Horsepower 393
Speed of Rotation 396
Temperature Rise During Compression 397
Sonic or Acoustic Velocity 399
Mach Number 402
Specific Speed 402
Compressor Equations in Si Units 403
Polytropic Compressor 405
Adiabatic Compressor 408
Efficiency 409
Mass Flow Rate, w 409
Mechanical Losses 410
Estimating Compressor Horsepower 411
Multistage Compressors 412
Multicomponent Gas Streams 414
Affinity Laws 422
Speed 423
Impeller Diameters (Similar) 423
Impeller Diameter (Changed) 424
Effect of Temperature 424
Affinity Law Performance 425
Troubleshooting of Centrifugal and Reciprocating Compressors 425
Nomenclature 429
Greek Symbols 431
Subscripts 432
Nomenclature 432
Subscripts 434
Greek Symbols 434
References 434
Pumps 434
Bibliography 435
References 435
Compressors 435
Bibliography 436
7 Mass Transfer 437
Introduction 437
Vapor Liquid Equilibrium 437
Bubble Point Calculation 441
Dew Point Calculation 442
Equilibrium Flash Composition 442
Fundamental 443
The Equations 444
The Algorithm 445
Nomenclature 446
Tower Sizing for Valve Trays 446
Introduction 446
The Equations 448
Nomenclature 452
Greek Letters 465
Packed Tower Design 466
Introduction 466
Pressure Drop 466
Flooding 466
Operating and Design Conditions 468
Design Equations 471
Packed Towers versus Trayed Towers 473
Economic Trade-Offs 473
Nomenclature 474
Greek Letters 474
Determination of Plates in Fractionating Columns By the Smoker Equations 474
Introduction 474
The Equations 474
Application to a Distillation Column 475
Rectifying Section: 475
Stripping Section: 476
Nomenclature 476
Multicomponent Distribution and Minimum Trays In Distillation Columns 477
Introduction 477
Key Components 477
Equations Surveyed 477
Fractionating Tray Stability Diagrams 479
Areas of Unacceptable Operation 479
Foaming 480
Flooding 480
Entrainment 480
Weeping/Dumping 480
Fractionation Problem Solving Considerations 481
Mathematical Modeling 481
The Fenske's Method for Total Reflux 483
The Gilliland Method for Number of Equilibrium Stages 484
The Underwood Method 485
Equations for Describing Gilliland's Graph 486
Kirkbride's Feed Plate Location 487
Nomenclature 487
Greek Letters 488
Examples and Solutions 488
References 499
Index 501
1
Computations with Excel Spreadsheet-UniSim Design Simulation
Engineers, technologists, and scientists have employed numerical techniques to solve a wide range of steady-state and transient problems, and energy and material balance equations. The fundamentals are essential in the basic operations of these techniques and the requirements are greater when new processes are designed. Engineers also need theoretical information and data from the literature to construct mathematical models with proper hypotheses. These mathematical models, which consist of a massive set of linear and non-linear equations, can be solved using established numerical analysis tools and process simulators. Furthermore, developing mathematical models sometimes involves experimental plans to obtain the required data for the models. Preparing an experimental plan is strongly dependent on the knowledge of the process with theory, where the whole modification can be produced by some form of mathematical models or regression analyses. This chapter deals with these important issues for chemical and process engineers in two sections:
Section I: This section covers the modeling and numerical analysis with the Excel spreadsheet program which deals with curve fitting, approximation, interpolation, numerical solutions of simultaneous linear and nonlinear equations, and numerical differentiation and integration.
Section II: This section covers process simulation using UniSim Design software which deals with the property estimation, equipment and process design, and case studies.
These two tools (the Excel spreadsheet and UniSim Design software) are introduced in this chapter and are used throughout the book to ease calculations related to process design and analysis. In this way, students and engineers can save time by using hands-on tools to ease the calculations and concentrate on the fundamental understanding of the phenomena occurring in the process design sequences.
SECTION I - NUMERICAL ANALYSIS
INTRODUCTION
Excel Spreadsheet
Microsoft Excel is part of the Microsoft Office. The Excel spreadsheet is today's leading software for problem solving which enables a chemical engineer to make computations and visualizations in the easiest way. Most people often use the Excel spreadsheet program for business or financial purposes, but it is also a powerful and versatile tool that can be used for a wide variety of chemical engineering applications and numerical analysis. One of its key benefits is bringing techno-economic information together. Process engineers can use the Excel spreadsheet for equipment and process design, modeling, simulation and optimization. Databases and pivot tables can be easily designed with the Excel spreadsheet to perform calculations, understand technical reports, and prepare charts and figures. These make an engineer's life easy in giving a presentation and trying to get a message across.
The Excel spreadsheet program has the following unique characteristics [1, 2]:
- 1,048,576 rows by 16,384 columns
- Maximum number of cell characters (32,767 characters)
- 1,026 horizontal and vertical page breaks
- Undo levels: 100 and Iterations: 32,767
- Largest allowed number via formula: 1.8×10308
- Number of available worksheet functions: 341
Designing graphs and charts helps engineers with analyzing and predicting trends. The Excel spreadsheet applications make the engineers' time usage more efficient and there is an enormous elimination of the time wasted on endless repetition of mathematical operations. The Excel spreadsheet program contains dozens of built-in functions, macros, add-ins and graphic modules that make it possible to develop powerful applications to solve process design problems. Students can also benefit from the Excel spreadsheet program to have a good adaption on its capabilities for their studies. It also makes mathematics very easy to understand in the rows and columns operations.
Martín and Martín de Juan [3] provided Excellent coverage of the Excel spreadsheet program for chemical engineering. In their chapter, after introductory text, they discussed basics, built-in functions, operations with cells (columns and rows), fitting, plotting and solving, building functions in VBA (Visual Basic for Applications) and have also provided some comprehensive examples. Ferreira et al. [4] also reviewed the application of spreadsheets in chemical engineering education in process design and process integration. In their paper, the Excel SOLVER feature was used for the optimization of several problems on pollution prevention and mass-exchange networks. They examined three non-linear problems: the (a) recovery of benzene from a gaseous emission; (b) design of a chemical reactor network; and (c) solution of material balances in the production of vinyl chloride from ethylene. Dephenolization of aqueous wastes was also presented as a linear example. They concluded that the formulating and solving linear and non-linear problems within the Excel spreadsheet program is instrumental in teaching optimization and design concepts.
In this chapter, we assumed that readers have basic knowledge of the Excel spreadsheet with hands-on experiences on cells (row and columns) and functions operations. This chapter covers selected basics and specific functions of Excel spreadsheet, calculation of trendline coefficients, Goal Seek and SOLVER add-in with some applied chemical engineering examples on numerical analysis. The key features of this chapter would be very useful for students and engineers at various levels and will be applied throughout the book whenever necessary.
Functions
There is a large number of built-in functions in Excel spreadsheet, but there is no need to learn them all, especially at once. For the application in this book, selected functions are presented in Table 1.1 and Table 1.2 with their proper syntaxes. Worksheet functions are predefined formulas in Excel spreadsheet to make calculations in the order specified by its parameters. The functions have two basic parts: equal sign (=) and syntax which include a function name and arguments, and the functions mostly return numerical values. A detailed list and explanations of the Excel spreadsheet functions are given by Techonthenet [5].
Trendline Coefficients
When one adds a trendline to a chart, the Excel spreadsheet program provides an option to display the trendline equation in the chart. The Excel spreadsheet functions can be also used to generate the trendline coefficients. This would allow calculating predicted y values for given values of x without a need to plot those data in the figure and read the coefficients from the Figures. Let's assume two named ranges as x and y to show input arguments to Excel spreadsheet functions. Table 1.3 shows syntaxes for finding trendline coefficients.
The combination of INDEX and LINEST functions can be also used to find the coefficients of the higher order polynomial. All functions shown in this table return the numeric values of the coefficients.
For linear trendline, slope (b) and intercept (a) of the trend line is obtained by two ways [8]:
- Using SLOPE and INTERCEPT functions
- Using LINEST functions
Table 1.1 Selected basic functions of Excel spreadsheet [2, 5].
Function Syntax AVERAGE AVERAGE (number1, [number2], ... [number_n])number 1,. : numbers, named ranges, arrays, or references to numbers.
EXP EXP (number)number: The power to raise e to.
IF IF(condition, value_if_true, [value_if_false])condition: value to test.
value_if_true: It is the value returned if condition is TRUE.
value_if_false: optional. It is the value returned if condition is FALSE.
INDEX INDEX (table, row_number, column_number)row_number: Row position in the table for lookup. This is the relative row position in the table and not the actual row number in the worksheet.
column_number: Column position in the table to lookup. This is the relative column position in the table and not the actual column number in the worksheet.
Returns: returns any data type such as a string, numeric, date, etc.
LN or LOG LN(number) or LOG(number)number: numeric value greater than 0.
MAX MIN MAX or MIN(number1, [number2, ... number_n])number1: It can be a number, named range, array, or reference to a number.
number2, ... number_n: optional. These are numeric values (numbers, named ranges, arrays, or references to numbers) and can be up to 30 values entered.
PI PI( ) with no arguments returns 3.14159265358979. ROW COLUMN ROW/COLUMN([reference])Reference: optional. reference to a cell or range of cells.
It returns row or column number of a cell reference.
SQRT SQRT(number)number: positive number; If the number is negative, the function gives an error.
STDEV STDEV(number1, [number2, ... number_n])number1: It can be a...
