Practical process control design with industrial applications / Alan M. Kugelman.

Includes bibliographical references and index.

Table of Contents
Preface xiii

1 Process Dynamics and Process Control Overview 1

1.1 Introduction 2

1.2 The Role of Process Control 3

1.3 Tag Naming Conventions 4

1.4 Control Loop Essentials 7

1.5 Process Dynamics and Dynamic Responses 14

1.6 Plant Testing 25

1.7 Classification of Process Control Strategies 28

1.8 Benefits of Control Applications 41

2 Feedback Control Essentials 44

2.1 Introduction 45

2.2 Single Loop Control, Simple, and Complex Cascades 46

2.3 Digital Control System (DCS)Work Environment 50

2.4 PID Control Algorithm Basics 57

2.5 Noise, Filters, Plant Testing, and Closed-Loop Control 93

2.6 Ratio Control 97

2.7 Single Input-Single Output Model-Based Control (MBC) 104

2.8 Cascade Wind-up 112

3 Feedforward Control Essentials 120

3.1 The Role of Feedforward Control 120

3.2 Ratio Control and Steady-State Feedforward Control 124

3.3 Dynamic Compensation via the Lead-Lag Algorithm 126

3.4 Ratio Control and Dynamic Feedforward Control 130

3.5 Incremental Steady-State Feedforward Control 133

3.6 Incremental Dynamic Feedforward Control 137

3.7 Engineering Relationships That Provide Feedforward Corrections 141

4 Process Analysis and Understanding 155

4.1 Business Drivers, Operating Plans, and Operational Objectives 156

4.2 Obtaining Useful Information 156

4.3 Use of Process Analysis 158

5 Split Range Control 178

5.1 Split Range Control Overview 178

5.2 Split Range Control Applications 181

6 Override Control 195

6.1 Override Control Overview 195

6.2 Override Control Applications 198

6.3 From Override Control to Conventional Constraint Control 205

7 Conventional Constraint Control 208

7.1 DMC’s Role in Multivariable Constraint Control 209

7.2 Introduction to Conventional Constraint Control 210

7.3 Natural Draft Heater Combustion Control via Conventional Constraint Control 210

7.4 Maximizing Heat Recovery 218

7.5 Conventional Constraint Control Cascade Structure 226

7.6 Alternate Signal Selector Locations in Constraint Control Designs 228

7.7 Active Constraint Variable Switches 231

7.8 Constraint Control Design Issues 233

8 Design Considerations 236

8.1 First Steps: Process Understanding and Operating Objectives 237

8.2 Basic Control Attributes, Control Options 238

8.3 Standard DCS Functionality 243

8.4 Corporate and Site Standards 244

8.5 Sample Time, Control Frequency and Controller Scheduling 246

8.6 Calculated Control Variables 246

8.7 Inferential Variables 247

8.8 Input Validation 252

8.9 Flow Compensation 258

8.10 Cascade Initialization and Wind-up Protection 259

8.11 Alarming and Operator Messaging 260

8.12 Interactions with Other Control Strategies 261

8.13 Testing to Judge Control Strategy Acceptability 263

9 Level Control 265

9.1 Introduction 265

9.2 Single Loop Level Control 266

9.3 Light-ends Tower Inventory Control 268

9.4 Level Controllers that Manipulate Multiple Flows 273

9.5 More Complex Level Control Applications 277

9.6 Averaging and Tight Level Controller Tuning 286

10 Heat Input/Heat Removal Controls 291

10.1 Introduction 291

10.2 Feed Preheat Controls 295

10.3 Control Strategies in Heat Integrated Units 311

10.4 Fired Heater Firing Controls 323

11 Energy Conservation Controls 339

11.1 Heat Recovery Maximization 340

11.2 Lowering Fired Heater Stack Excess O2 Targets 357

11.3 Reducing Tower Reboiler Duty and Reflux Flow 370

11.4 Reducing Stripping Steam Utilization 383

11.6 Reducing Reactor Treat Gas, Recycle Gas Flows 397

12 Tower Product Quality Controls 410

12.1 Tower Basics 412

12.2 Two-product Towers - Process Variable Summary 412

12.3 Two-product Towers - Common Product Quality Control CV-MV Pairs 419

12.4 Towers with Sidestream - Process Variable Summary 427

12.5 Towers with Sidestream - Common Product Quality Control CV-MV Pairs 432

12.6 Cutpoint, Fractionation, and Their Impact on Tower Operations 435

12.7 Two-product Towers - Overview of Conventional Advanced Control Applications 443

12.8 Towers with Sidestream - Overview of Conventional Advanced Control Applications 453

12.9 Two-product Towers - Conventional Advanced Control Application Examples 463

12.10 Towers with Sidestream - Conventional Advanced Control Application Examples 485

13 Fractionator Product Quality Control 497

13.1 Fractionator Unit Characteristics 499

13.2 Feed True Boiling Point (TBP) Distillation Curve, Cutpoint, and Fractionation 505

13.3 Crude Distillation Unit, CDU - The Most Important Primary Fractionator 515

13.4 Reactor Effluent Product Separation Section Main Fractionators 541

14 Reactor Conversion Control 554

14.1 Reactor Control Fundamentals 555

14.2 Reactor System Unit Configurations 564

14.3 Reactor System Control Objectives, CVs, MVs, and DVs 581

14.4 Conventional Reactor Advanced Control Applications 584

Control, Inlet Temperature Maximization 608

References 613

Index 615

"Process design is based on steady state conditions -- process variables, and physical and chemical parameters, are assumed known, fixed and time invariant. However, refinery and chemical plant operations are never at steady state, and it is the transient nature of real-world operations that makes process control an essential requirement for achieving safe and acceptable plant performance. The primary roles of the process control strategies implemented in an operating plant are to (i) hold plant operations at a desired operating point despite process upsets, (ii) provide smooth, fast and safe transitions from one operating point to another, and (iii) keep plant operations on the safe side of limiting process constraints. The control strategy design fundamentals described and discussed are applied to develop numerous specific control strategies in a wide variety of realistic process configurations."-- Provided by publisher.

About the Author
Alan M. Kugelman, PhD, has more than 40 years’ experience in process control application design and implementation in capital projects, DCS migration projects and DCS modernization projects. Working for ExxonMobil Research and Engineering Company (Florham Park, NJ, later in Fairfax, Va.), he developed his process control applications design and implementation expertise during three onsite assignments at ExxonMobil sites in Europe and Japan. He then supported ExxonMobil control applications activities, in both refineries and chemical plants worldwide, from central engineering offices in Brussels, Florham Park, and Fairfax. He developed, and taught company-administered control application training courses to site control engineers worldwide.