Distillation Control An Engineering Perspective

by Smith, Cecil L.

• ISBN13: 9780470381946
• ISBN10: 0470381949
• Edition: 1st
• Format: Hardcover
• Copyright: 2012-05-29
• Publisher: Wiley

Summary

Today, distillation is by far the most common separation technique used in the chemical and petroleum industries. Distillation Control approaches this subject from a process engineering perspective to explain the use of steady-state simulations to develop, to analyze, and to troubleshoot all aspects of column controls, including their practical application and cost benefits. Practicing engineers and other professionals working in process facilities that use distillation to separate materials will find this book a reliable companion.

Author Biography

Cecil L. Smith, PhD, is president of Cecil L. Smith, Inc., a firm specializing in automation technology, founded after he left the faculty of Louisiana State University Dr. Smith has more that thirty-five years of experience in process control. With expertise spanning almost all control technology currently in use in industrial production facilities. Dr. Smith has been listed among InTech magazine's fifty most influential industry innovators.

Table of Contents

Preface	p. ix
Principles	p. 1
Separation Processes	p. 2
Total Material Balance	p. 9
Reflux and Boilup Ratios	p. 13
Total Material Balance around Condenser	p. 18
Total Material Balance around Reboiler	p. 21
Component Material Balances	p. 24
Energy and the Separation Factor	p. 28
Multicomponent Distillation	p. 35
Stage-by-Stage Separation Model	p. 38
Formulation of the Control Problem	p. 47
Tower Internals	p. 50
Flooding	p. 55
Tray Hydraulics	p. 59
Inverse Response in Bottoms Level	p. 62
Composition Dynamics	p. 65
References	p. 69
Composition Control	p. 70
Product Specifications	p. 71
Columns in Series	p. 75
Composition Analyzers	p. 78
Temperature	p. 83
Distillate Composition Control: Constant Boilup	p. 91
Distillate Composition Control: Constant Bottoms Flow	p. 96
Operating Lines	p. 100
Temperature Profiles	p. 106
Feed Composition Disturbances	p. 113
Bottoms Composition Control	p. 116
Propagation of Variance in Level Control Configurations	p. 122
Level Control in Direct Material Balance Configurations	p. 126
Pressure Control and Condensers	p. 136
Pressure Control	p. 137
Once-Through Heat Transfer Processes	p. 142
Water-Cooled Condensers	p. 147
Flooded Condensers	p. 151
Air-Cooled Condensers	p. 159
Partial Condensers	p. 162
Atmospheric Towers	p. 167
Vacuum Towers	p. 169
Floating Pressure/Pressure Minimization	p. 173
Reference	p. 179
Reboilers and Feed Preheaters	p. 180
Types of Reboilers	p. 181
Steam-Heated Reboilers	p. 185
Hot Oil	p. 195
Fired Heaters	p. 198
Feed Preheater	p. 200
Economizer	p. 204
References	p. 208
Applying Feedforward	p. 209
Feed Flow and Composition	p. 210
Internal Reflux Control	p. 220
Extreme Feedforward	p. 226
Feedforward for Bottoms Level	p. 229
Feedforward for Column Pressure	p. 234
Product Compositions	p. 238
Reference	p. 242
Unit Optimization	p. 243
Energy and Separation	p. 244
Optimization of a Column	p. 250
Constraints in Distillation Columns	p. 255
Control Configurations for Single Constraint	p. 258
Control Configurations for Multiple Constraints	p. 266
References	p. 277
Double-End Composition Control	p. 273
Defining the Problem	p. 273
Options for Composition Control	p. 275
Relative Gain	p. 283
Relative Gains from Open Loop Sensitivities	p. 290
Relative Gains for Other Configurations	p. 294
Ratios for Manipulated Variables	p. 296
Effect of Operating Objectives	p. 300
MPC	p. 303
Complex Towers	p. 306
Heat Integration	p. 307
Side Heater/Side Cooler	p. 311
Sidestreams	p. 316
Withdrawing a Liquid Sidestream	p. 319
Withdrawing a Vapor Sidestream	p. 322
Composition Control in Sidestream Towers	p. 324
Index	p. 329
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