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TitleProcess Analysis and Simulation in Chemical Engineering
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LanguageEnglish
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Table of Contents
                            Preface
Contents
About the Authors
Chapter 1: Process Simulation in Chemical Engineering
	1.1 Introduction
	1.2 Chemical Process Simulators
	1.3 Types of Process Simulators
		1.3.1 Sequential Modular Simulators
		1.3.2 Simultaneous or Equation Oriented Simulators
		1.3.3 Hybrid Simulators
		1.3.4 Aspen Plus and Aspen Hysys
	1.4 Applications of Process Simulation
		1.4.1 Computer-Aided Design
		1.4.2 Process Optimization
		1.4.3 Solution of Operating Problems
		1.4.4 Other Applications
	1.5 Convergence Analysis
		1.5.1 Convergence Methods (Babu 2004 ; Dimian 2003; Seider et al. 2004)
			1.5.1.1 Newton-Type Methods
				Bounded Functions and Derivatives
				Closeness to Solution
				Methods That Do not Require Derivatives
			1.5.1.2 First Order Methods
				Direct Substitution Methods
				Relaxation Methods
		1.5.2 Problems with Simple Recycles
		1.5.3 Partitioning and Topological Analysis
		1.5.4 Nested Recycles
	1.6 Introductory Example
		1.6.1 Problem Description
		1.6.2 Simulation Using Aspen HYSYS
		1.6.3 Simulation Using Aspen Plus
	1.7 Sensitivity Analysis
		1.7.1 Sensitivity Analysis in Aspen Plus
		1.7.2 Sensitivity Analysis in Aspen HYSYS
	1.8 Design Specifications
	1.9 Summary
	1.10 Problems
	References
Chapter 2: Thermodynamic and Property Models
	2.1 Introduction
	2.2 Ideal Model
	2.3 Equations of State
		2.3.1 Redlich-Kwong
		2.3.2 Soave-Redlich-Kwong
		2.3.3 Peng-Robinson
	2.4 Activity Coefficient Models
		2.4.1 Van Laar Model
		2.4.2 Wilson Model
		2.4.3 NRTL (Nonrandom Two Liquids)
		2.4.4 UNIQUAC
		2.4.5 UNIFAC
	2.5 Special Models
		2.5.1 Polymeric Systems
			2.5.1.1 Property Methods
			2.5.1.2 Activity Coefficient Models
			2.5.1.3 Equations of State
		2.5.2 Electrolytic System
			2.5.2.1 Property Methods
			2.5.2.2 Activity Coefficient Models
			2.5.2.3 Electrolytic NRTL Model
			2.5.2.4 Pitzer Model
			2.5.2.5 Bromley-Pitzer Model
	2.6 Integration of the Activity Models with Equations of the State
	2.7 Selection of Thermodynamic Model
		2.7.1 Selection of the Property Model
		2.7.2 Selection of the Properties Model
		2.7.3 Validate the Physical Properties
		2.7.4 Describe Additional Components to the Database
		2.7.5 Obtain and Use Experimental Data
	2.8 Example of Property Model Selection
	2.9 Example of Phase Diagram
		2.9.1 Simulation in Aspen HYSYS
		2.9.2 Simulation in Aspen Plus
		2.9.3 Results Comparison
	2.10 Example of Parameter Adjustment
		2.10.1 Example Using an Activity Coefficient Model
		2.10.2 Example Using an Equation of State
		2.10.3 Comparison and Results Analysis
	2.11 Hypothetical Components
		2.11.1 Usage in Aspen HYSYS
		2.11.2 Usage in Aspen Plus
	2.12 Summary
	2.13 Problems
	References
Chapter 3: Fluid Handling Equipment
	3.1 Introduction
	3.2 General Aspects
		3.2.1 Background
		3.2.2 Piping
			3.2.2.1 Aziz, Govier and Fogarasi (Aziz and Govier 1972)
			3.2.2.2 Baxendell and Thomas (Baxendell 1961)
			3.2.2.3 Beggs and Brill (1973)
			3.2.2.4 Duns and Ros (1963)
			3.2.2.5 Gregory Aziz Mandhane Pressure Gradient (Gregory and Mandhane 1975)
			3.2.2.6 Hagedorn and Brown (Hagedorn 1965)
			3.2.2.7 HTFS Models (Aspen Technology Inc. 2009)
			3.2.2.8 OLGAS 2000 (Aspen Technology Inc. 2005b, Operation Guide)
			3.2.2.9 Orkisewski (1967)
			3.2.2.10 Poettman and Carpenter (Poettmann 1952)
			3.2.2.11 Tacite Hydrodynamic Mode (Aspen Technology Inc 2005b, Operation Guide)
			3.2.2.12 Tulsa (Aspen Technology Inc 2005b, Operation Guide)
		3.2.3 Pumps
		3.2.4 Compressors and Expanders
	3.3 Modules Available in Aspen Plus
	3.4 Modules Available in Aspen HYSYS
	3.5 Gas Handling Introductory Example
		3.5.1 Problem Description
		3.5.2 Simulation in Aspen HYSYS
		3.5.3 Results Analysis
	3.6 Liquid Handling Introductory Example
		3.6.1 Problem Description
		3.6.2 Process Simulation
		3.6.3 Results Analysis
	3.7 Summary
	3.8 Problems
	References
Chapter 4: Heat Exchange Equipment and Heat Integration
	4.1 Introduction
	4.2 Types of Programs Available
	4.3 General Aspects
		4.3.1 Shortcut Calculation (Holman 1999)
		4.3.2 Rigorous Calculation (Holman 1999)
			4.3.2.1 Geometry
				Tubes
				Shell
				Baffles
		4.3.3 Calculation Models
			4.3.3.1 Simple End Point Model
			4.3.3.2 Simple Weighted Model
			4.3.3.3 Simple Steady State Rating Model
			4.3.3.4 Dynamic Rating
			4.3.3.5 Rigorous Shell and Tube
	4.4 Modules Available in Aspen Plus
	4.5 Modules Available in Aspen HYSYS
		4.5.1 Thermodynamic Heat Exchangers
	4.6 Introductory Example
		4.6.1 Problem Description
			4.6.1.1 Calculate a n-Propanol Horizontal Condenser
		4.6.2 Simulation in Aspen Plus
		4.6.3 Simulation in Aspen HYSYS
			4.6.3.1 Geometric Data Entry
		4.6.4 Simulation in Aspen Exchanger Design and Rating
		4.6.5 Results Analysis
			4.6.5.1 Top Pressure Change
			4.6.5.2 Propanol Flow Change
	4.7 Process Heat Integration
		4.7.1 Introduction
		4.7.2 Theoretical principles
			4.7.2.1 Targeting, Composite Curves, and Grand Composite Curves
			4.7.2.2 General Rules for the Pinch Design Method
		4.7.3 Aspen Energy Analyzer
			4.7.3.1 Example: Manual Input Network
			4.7.3.2 Software Proposed Network and Optimized Network
	4.8 Summary
	4.9 Problems
	References
Chapter 5: Chemical Reactors
	5.1 Introduction
	5.2 General Aspects
		5.2.1 Chemical Reaction
		5.2.2 Stoichiometry
		5.2.3 Conversion (Fogler 2008)
		5.2.4 Selectivity
		5.2.5 Reaction Kinetics
		5.2.6 Kinetic of Heterogeneous Reactions
	5.3 Equations for Reactor Design
		5.3.1 Continuous Stirred Tank Reactor
		5.3.2 Plug Flow Reactor (PFR)
		5.3.3 Batch Reactor (Batch)
	5.4 Modules Available in Aspen Plus
	5.5 Available Modules in ASPEN HYSYS
	5.6 Introductory Example of Reactors
		5.6.1 Problem Description
			5.6.1.1 Aspen Plus Simulation
			5.6.1.2 Stoichiometric Reactor (RSTOIC)
			5.6.1.3 Gibbs Reactor (RGIBBS)
			5.6.1.4 Kinetic Reactors
			5.6.1.5 Plug Reactor (RPLUG)
			5.6.1.6 Stirred Tank Reactor (RCSTR)
		5.6.2 Simulation in Aspen Hysys
			5.6.2.1 Reaction Specifications and Reaction Sets
			5.6.2.2 Conversion Reactor Configuration
			5.6.2.3 Kinetic Reactor Configuration
			5.6.2.4 CSTR reactor
		5.6.3 Results Analysis
	5.7 Propylene Glycol Reactor Example
		5.7.1 General Aspects
		5.7.2 Process Simulation in Aspen Plus
		5.7.3 Results Analysis
	5.8 Methanol Reforming Reactor
		5.8.1 Problem Description
		5.8.2 Simulation in Aspen Plus
		5.8.3 Simulation in Aspen Hysys
		5.8.4 Analysis and Results Comparison
	5.9 Summary
	5.10 Problems
	References
Chapter 6: Gas-Liquid Separation Operations
	6.1 Introduction
	6.2 Available Modules in Aspen Plus
		6.2.1 Shortcut Methods
			6.2.1.1 Fenske Method
			6.2.1.2 Underwood Method (Eckert and Vanek 2001; Thomas 1991)
			6.2.1.3 Gilliland Method (Glasser et al. 2000)
		6.2.2 Rigorous Methods
			6.2.2.1 Stage by Stage Methods (Henley and Seader 1998)
			6.2.2.2 Bubble Point Methods
			6.2.2.3 Sum Rates Method
			6.2.2.4 2N Newton Methods
			6.2.2.5 Simultaneous Correction Methods
			6.2.2.6 Double Iteration Methods (Inside-Out Methods)
			6.2.2.7 Relaxation Methods
			6.2.2.8 Homotopy-Continuation Methods
			6.2.2.9 Radfrac
	6.3 Modules Available in Aspen Hysys
		6.3.1 Predefined Columns
		6.3.2 Shortcut Calculation Model
		6.3.3 Column Interface
	6.4 Distillation Introductory Example
		6.4.1 Problem Description
		6.4.2 Simulation in Aspen Plus
		6.4.3 Simulation in Aspen Hysys
		6.4.4 Results Analysis and Comparison
	6.5 Absorption Introductory Example
		6.5.1 Problem Description
		6.5.2 Process Simulation
	6.6 Enhanced Distillation
		6.6.1 Residue Curves Map
			6.6.1.1 Residue Curve Maps for Ternary Mixtures
			6.6.1.2 Residue Curve Map Construction
			6.6.1.3 Properties of Residue Curve Maps
			6.6.1.4 Selecting the Separation Agent
			6.6.1.5 Residue Curve Map Applications
		6.6.2 Extractive Distillation
			6.6.2.1 Problem Description
			6.6.2.2 Simulation in Aspen Plus
			6.6.2.3 Glycerol Recirculation
	6.7 Nonequilibrium Models
		6.7.1 Nonequilibrium Model Example
	6.8 Columns Thermal and Hydraulic Analysis
		6.8.1 Thermal Analysis
		6.8.2 Hydraulic Analysis
		6.8.3 Application Exercise
			6.8.3.1 Feeding Stage
			6.8.3.2 Feeding Temperature
			6.8.3.3 Packing Type
			6.8.3.4 Additional Remarks
	6.9 Summary
	6.10 Problems
	References
Chapter 7: Process Optimization in Chemical Engineering
	7.1 Introduction
	7.2 Formulation of Optimization Problem
		7.2.1 Degrees of Freedom
		7.2.2 Objective Function
		7.2.3 Classification of Optimization Problems
			7.2.3.1 Linear Programming Problems
			7.2.3.2 Nonlinear Problems and Sequential Quadratic Programming
			7.2.3.3 Mixed Integer Nonlinear Programming
	7.3 Optimization in Sequential Simulators
		7.3.1 General Aspects
	7.4 Introductory Example
		7.4.1 Aspen Plus Simulation
			7.4.1.1 Raw Material Cost
			7.4.1.2 Utilities Cost
			7.4.1.3 Pumps
			7.4.1.4 Heat Exchangers
			7.4.1.5 Distillation Columns
		7.4.2 Sensitivity Analysis
			7.4.2.1 Process Variables
		7.4.3 Results
			7.4.3.1 Objective Function
	7.5 Summary
	7.6 Problems
	References
Chapter 8: Dynamic Process Analysis
	8.1 Introduction
	8.2 General Aspects
		8.2.1 Process Control
		8.2.2 Controllers
	8.3 Introductory Example
		8.3.1 Dynamic State Simulation
	8.4 Gasoline Blending
		8.4.1 Steady State Simulation
		8.4.2 Dynamic State Simulation
		8.4.3 Disturbances
		8.4.4 Recommendations
	8.5 Pressure Relief Valves
		8.5.1 General Aspects
		8.5.2 Application Example
		8.5.3 Dynamic State Simulation
	8.6 Control of the Propylene Glycol Reactor
	8.7 Control of Distillation Columns
		8.7.1 General Aspects
		8.7.2 Distillation Column Example
	8.8 Summary
	8.9 Problems
	References
Chapter 9: Solids Operations in Process Simulators
	9.1 Introduction
	9.2 General Aspects
		9.2.1 Separation or Classification
			9.2.1.1 Hydrocyclones
			9.2.1.2 Cyclones(Infar 2011)
			9.2.1.3 Centrifuges(Infar 2011)
			9.2.1.4 Screens(Infar 2011)
			9.2.1.5 Hydraulic Classifiers
			9.2.1.6 Spiral Classifiers
		9.2.2 Comminution
		9.2.3 Filtration
		9.2.4 Crystallization
		9.2.5 Particle Size Distribution Meshes
	9.3 Modules in Aspen Plus
	9.4 Modules in Aspen HYSYS
	9.5 Crusher Introductory Example
		9.5.1 General Aspects
		9.5.2 Simulation in Aspen Plus
		9.5.3 Results Analysis
	9.6 Solids Handling Example
		9.6.1 General Aspects
		9.6.2 Simulation in Aspen Plus
		9.6.3 Results Analysis
	9.7 Summary
	References
Chapter 10: Case Studies
	10.1 Introduction
	10.2 Simulation of Nylon 6,6 Resin Reactor
		10.2.1 Problem Description
		10.2.2 Polymerization Reaction Kinetics
		10.2.3 Continuous Production
		10.2.4 Batch Production
		10.2.5 Results Comparison
	10.3 Azeotropic Distillation of Water-Ethanol Mixture Using Cyclohexane as Entrainer
		10.3.1 General Aspects
		10.3.2 Process Simulation
			10.3.2.1 Process Equipment
			10.3.2.2 Convergence and Specifications for Recycles
		10.3.3 Convergence Recommendations
	10.4 Ethylene Oxide Production
		10.4.1 Process Description
		10.4.2 Aspen HYSYS Simulation
			10.4.2.1 Gas Compression
			10.4.2.2 Chemical Reaction
			10.4.2.3 Separation
	10.5 Economic Evaluation Using Aspen Icarus (Guevara 2010)
		10.5.1 General Aspects
			10.5.1.1 Income Tax Percentage
			10.5.1.2 Inflation
			10.5.1.3 Product Price Increase
			10.5.1.4 Raw Material Price Increase
			10.5.1.5 Minimum Wage Increase
			10.5.1.6 Wages
			10.5.1.7 Utilities Prices
		10.5.2 Simplifications
		10.5.3 Aspen Icarus Simulation
			10.5.3.1 Property Sets
			10.5.3.2 Utilities Definition
			10.5.3.3 Transition to Aspen Icarus
			10.5.3.4 Equipment Sizing
			10.5.3.5 Economic Evaluation
		10.5.4 Results Analysis
			10.5.4.1 Equipment Cost
			10.5.4.2 Cash Flow
			10.5.4.3 Economic Indexes
	References
Index
                        
Document Text Contents
Page 1

Iván Darío Gil Chaves
Javier Ricardo Guevara López
José Luis García Zapata
Alexander Leguizamón Robayo
Gerardo Rodríguez Niño

Process Analysis
and Simulation
in Chemical
Engineering

Page 2

Process Analysis and Simulation in Chemical
Engineering

Page 268

shortcut method to estimate them. However, contrary to Aspen Plus
®
, Aspen

HYSYS
®

has an additional internal flowsheet especially for designing specific

columns with their respective accessories.

6.3.1 Predefined Columns

Aspen HYSYS
®
has different predefined columns that correspond to several of the

most frequent configurations for separating operations (Table 6.3).

All of these columns start from the same models which have the inner interface

for columns; however, they are adjusted according to the application required by

the column along with its accessories and convergence models.

6.3.2 Shortcut Calculation Model

Aspen HYSYS
®
also has a shortcut method for distillation columns that use the

Fenske–Underwood method to calculate simple columns with reflux. In this mode,

the minimum reflux of Underwood is established, and the minimum stage number

of Fenske. Through a specified reflux rate it is possible to calculate vapor and liquid

flow in enrichment and splitting sections, the condenser and reboiler duty, the

number of ideal stages required and the optimal feeding stage (Fig. 6.4).

Table 6.3 Predefined modules available in Aspen HYSYS
®
for gas–liquid separating equipment

Icon Type of column

Column with reboiler and condenser (partial or total)

Absorber with condenser (partial or total)

Absorber

Absorber with reboiler

Three-phase distillation

Liquid–liquid extractor

Fig. 6.4 Shortcut method
module in Aspen HYSYS

®

252 6 Gas–Liquid Separation Operations

Page 269

The shortcut method is only an estimate of the column performance, and for this

case, is only limited to columns with simple reflux. In order to obtain more actual

results a rigorous model of column shall be used; however, the shortcut method

calculates very well previous estimates to use rigorous models.

6.3.3 Column Interface

As mentioned above, Aspen HYSYS
®
has a special internal interface to calculate

and design columns. There, all the equipment sets that could eventually involve the

designing of one of these separating units are introduced. This interface is accessed

through the button shown in Fig. 6.5.

This interface can also be accessed through the column information diagram

using the button of Fig. 6.6.

Column environment corresponds to a flowsheet where only relevant modules
are provided for the column designing. Below is an example of the use of this

interface:

As shown in Fig. 6.7, the object palette in this environment only has equipment

relevant for the column designing, as well as balance operations and Dynamics

options. There are displayed several known equipment sets such as pumps, separa-

tors, exchangers, valves, and mixers, among others. However, new models are

added for the reboiler, the condenser, and column sections (Table 6.4).

In this manner, a column can be designed with additional equipment of a freer

manner, inclusive allowing the use of logical operations and control equipment.

6.4 Distillation Introductory Example

6.4.1 Problem Description

In order to illustrate the use of the corresponding modules both in Aspen Plus
®
and

Aspen HYSYS
®
, distillation of styrene and ethylbenzene is studied. This separation

Fig. 6.5 Icon blank column sub-flowsheet interface in Aspen HYSYS
®

Fig. 6.6 Icon access to column environment from a column already designed in Aspen HYSYS
®

6.4 Distillation Introductory Example 253

Page 536

Straight lines balance, steps, 290

Strategy

hybrid, 6

sequential, 6, 7

simultaneous, 3

SQP, 349

Streams

arrangements / combinations, 20, 148, 181

in Aspen HTFS+®, 191
ethanol and gasoline, 391

feed, 3, 21, 23, 117, 156, 157, 211, 220,

245, 264, 278, 310, 313, 323, 331,

334, 339, 380, 381, 391, 392, 438,

439, 441, 442, 444, 466, 468

hot gas, 38

initialization, 16

liquid and vapor, 282, 301

product, 3, 25, 43, 117, 197, 202, 217, 263,

295, 296, 301, 319, 503

recirculation, 4

recycle, 5, 14, 16, 17, 463, 466, 470,

473–475

reflux, 466, 470, 473, 475

side, 244, 304, 308

tear, 1, 2, 5, 10, 11, 14, 16–20, 37, 38, 47,

475, 477

value, 1, 18, 33, 473

Study

cases, 43, 44, 459, 478

revamping, 10

simulation, 8

Subroutine

design mode, 3, 140

rating mode, 3

Substances, 64

Sullivan, S.L., 247, 302

Surface

geometric configuration, 210

area, valves set point, 1

System, 64, 65

algebraic equation, 5

binary, 57–60

chemical, 373

complete, 27

control, 2, 290, 379, 414

distillation, 281

electrolytic, 64–68

thermodynamic properties, 64, 65

equations, 1, 6, 406

gas compression, 103

heterogeneous, 277

mechanic, 372

methanol, 69

nodes, 130

pentane–hexane–heptane, 285

pipes, 130

polymeric, 62–63

in the simulation, 191

ternary, 288

thermal/electric, 226

transport, 114

T
Tao, L., 277

Tarquin, A.J., 346

Task(s)

describe the components adequately, 82

estimating any parameter, 141

obtain and use the data, 188

select polar components, 60

validate the physical properties, 72, 73

Taylor, R., 12, 14, 247, 248, 256, 290, 303,

306, 307

Temperature(s)

adjustment, 337

bubble, 246

changes, 114

feed, 42, 227, 334, 337, 339, 363

interface, 307

liquid, 308

profile, 246, 260, 262, 268, 270, 271, 274,

295, 322, 331, 416–419, 482

stream, 190, 275

vapor, 309

variation, 334, 419

Theory

atomic, 196

Debye-Hückel, 67

transfer, 139

Thermodynamic, 21, 37, 45, 139, 141,

151–154, 167, 200, 202, 204, 205,

209, 213, 220, 244, 247, 301, 302,

306, 326, 327

electrolytic, 65

Thiele, E.W., 245

Thomas, M., 243, 302

Timonen, J.A.M., 175

Tolsma, J., 282, 289

Tool(s)

informatics, 2

primary design, 241

simulator, 383

Topological Analysis, 17–18

Towler, G., 10, 288

Treybal, R., 246, 301

522 Index

Page 537

Tube, 143, 145

calculation, 105

shape

fixed, 143, 145

U, 143, 145

specifications, 130, 146

Type

available programs, 139–140

exchangers, 146, 151, 154, 355

packaging, 306, 307

Tyreus, B.D., 419

U
Umbach, J.S., 177, 180

UNIFAC, 60–62, 95, 96, 391

Urdaneta, R., 272

Uses

applications, 7–10, 62, 70, 98, 144,

146–148, 152, 195, 290–291,

434, 487

in Aspen HYSYS®, 93–96
in Aspen Plus®, 97–98
process simulation, 8–10

Utilities

calculator, 352, 359–361

envelope utility, 82, 85, 87

Uyazan, A.M., 365

V
Valle del Cauca, 487, 490, 511

Values

binary, 347

optimal, 243

Valves

control, 222, 223, 374, 376, 379, 380, 385,

391, 392, 399, 402, 403, 406, 408,

409, 415

fast opening, 376

relief, 114, 400, 401, 403, 406

safety, 400

Vane, k, T., 243, 301, 302

Van Krevelen, D., 60, 457

Vapor phase, 53, 55, 68, 69, 73, 74, 78, 220,

226, 238, 244, 277, 278, 284, 290,

301, 303–307, 309, 321, 478

Vapor–liquid equilibrium (VLE), 75–76, 88

Vapor-liquid- liquid equilibrium (VLLE), 74

Variable(s)

binary/integer, 347, 348

composition, 1

continuous, 347, 348

controlled, 374, 375, 377, 378, 381, 385,

395, 418

dependent, 9, 43, 44

design, 345, 359

discrete, 347, 348

disturbance, 374

flows, 1, 132

independent, 9, 33, 43, 44, 354, 363

input, 3, 373–375

iteration, 5, 245, 246

manipulated, 40, 46, 320, 374, 375,

381, 418, 419

measured, 375

MESH/column state, 245, 247

operation, 2, 343, 345, 346, 356

optimization, 187, 346, 350, 364, 365

output, 3, 6, 373, 375

pressure, 1

problem, 344

process, 6, 9, 120, 125, 325, 345, 347,

363, 364, 371, 373, 378, 383

relaxed, 348

temperature, 1, 43

type, 18, 40, 43, 347

Vectors, 3, 10, 12, 14, 284

Velocities

fluids, 104, 105, 107, 148

gas, 107, 108

Volatility, relative, 243, 244, 287, 290, 462

W
Wahnschafft , O., 285, 288

Wang, J., 246

Wilson, 58, 59, 61, 100, 101

Z
Zone(s)

feasibility, 346

instability, 225, 376

Index 523

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