Emphasis on improved quality and performance of distilled products and the demand for reduced operating costs place a heavy burden on both the personnel responsible for profitability and the manufacturing department charged with operating the processing equipment. There have been dramatic improvements in the computer software and hardware used to simulate and model the distillation process and potential response to experimentation, but mastering the art of distillation process and control still requires solid understanding of a large body of information.
With a focus on achieving product purity at low cost, Distillation Control, Optimization, and Tuning: Fundamentals and Strategies highlights core concepts. These include process variables for continuous binary distillation columns and the four basic control strategies, the distillate and bottoms product quality performance objectives, and the tuning of process control loops. Without dwelling on complex mathematical descriptions, the book presents the fundamentals of process control of a distillation column as a separation and purification unit operation. It covers the concepts and functional criteria that are critical to successful implementation of process control, as well as measurement and improvement of product quality performance. It describes how process control loops for distillation columns can be tuned for stable operation, with a balance between minimum variability from setpoint changes and excellent response to load disturbances.
Designed for students, engineers, technicians, and plant operators alike, this book emphasizes the prevailing need to strike a balance between the details of hypotheses and good engineering judgment. The author outlines learning objectives at the beginning of each chapter and includes chapter-end summaries, exercises, and references to help readers acquire essential knowledge and understanding. The result is a resource that will inform future decisions for the design, operation, and troubleshooting of distillation process control systems.
Lanny Robbins (Larco Technologies LLC Midland Michigan USA)
Country of Publication:
29 March 2017
Unit 1: Introduction and Overview Course Coverage Purpose Audience and Prerequisites Study Materials Organization and Sequence Course Objectives Course Length Unit 2: Distillation Control Variables Distillation Column Inlet Streams Distillation System Outlet Streams Controlled Variables Unit 3: Separation Power Relative Volatility in One Theoretical Stage Separation Power with Multiple Stages Separation Power and Energy Consumption Unit 4: Distillate/Feed Material Balance Split Material Balances Temperature Gradient per Theoretical Stage Temperature Change from D/F Shift Unit 5: Distillation Control Strategies Column Pressure Control Temperature Control with Distillate Flow Rate Temperature Control with Reflux Flow Rate Temperature Control with Boilup(Steam Rate) Temperature Control with Bottoms Flow Rate Side Draw Flow Rate Distillate Vapor Flow Rate Unit 6: Constraints Mechanical and Hydraulic Constraints Heat Transfer Constraints Stripping Mass Transfer Constraint Rectification (Absorption) Mass Transfer Constraint Unit 7: Optimizing Product Quality Performance Quality Performance Measurement Frequency of Failure Optimize MRT Between Distillate and Bottoms Quality Avoid Excessive Use of Steam Reduce Variability Optimize with Expert System Advisor Unit 8: PID Feedback Control Loop The Feedback Control Loop Proportional Integral Derivative Parallel and Series Algorithms Unit 9: Closed Loop Tuning of Controllers Trial and Error Tuning of Control Loops Ultimate Gain Tuning of Control Loops Troubleshooting an Oscillating Control Loop Quarter Decay Ratio tuning of Control Loops Pattern Recognition Tuning of Self Regulating Control Loops Effect of Proportional Gain Effect of Integral (Reset) Action Pattern Recognition Tuning of Integrating Control Loops Unit 10: Open Loop Testing of Process Response Self Regulating Process Response Ziegler-Nichols (Z-N) Open Loop Tuning Rules Two Point Characterization of FOPDT Process Response Quarter Decay Ratio (QDR) Tuning Rules Internal Model Control (IMC) Tuning Rules Integrating Process Response Appendix
Dr. Lanny Robbins is the president of Larco Technologies. He retired as a Research Fellow after 37 years at The Dow Chemical Company in Midland, Michigan. He received the Marston Medal, the top honor awarded by the Engineering Department at Iowa State University. His expertise is in fundamental chemical engineering research and pilot plant process development, especially for separation and purification processes.