Plantwide Control Recent Developments and Applications -- Contents -- Preface -- List of Contributors -- Part 1 Overview and Perspectives -- 1 Introduction -- 1.1 Background -- 1.2 Plantwide Control -- 1.3 Scope and Organization of the Book -- References -- 2 Industrial Perspective on Plantwide Control -- 2.1 Introduction -- 2.2 Design Environment -- 2.3 Disturbances and Measurement System Design -- 2.4 Academic Contributions -- 2.5 Conclusions -- References -- Part 2 Tools and Heuristics -- 3 Control Degrees of Freedom Analysis for Plantwide Control of Industrial Processes -- 3.1 Introduction -- 3.2 Control Degrees of Freedom (CDOF) -- 3.3 Computation Methods for Control Degrees of Freedom (CDOF): A Review -- 3.4 Computation of CDOF Using Flowsheet-Oriented Method -- 3.4.1 Computation of Restraining Number for Unit Operations -- 3.5 Application of the Flowsheet-Oriented Method to Distillation Columns and the Concept of Redundant Process Variables -- 3.6 Application of the Flowsheet-Oriented Method to Compute CDOF for Complex Integrated Processes -- 3.7 Conclusions -- References -- 4 Selection of Controlled Variables using Self-optimizing Control Method -- 4.1 Introduction -- 4.2 General Principle -- 4.3 Brute-Force Optimization Approach for CV Selection -- 4.4 Local Methods -- 4.4.1 Minimum Singular Value (MSV) Rule -- 4.4.2 Exact Local Method -- 4.4.3 Optimal Measurement Combination -- 4.4.3.1 Null Space Method -- 4.4.3.2 Explicit Solution -- 4.4.3.3 Toy Example -- 4.5 Branch and Bound Methods -- 4.6 Constraint Handling -- 4.6.1 Parametric Programming Approach -- 4.6.2 Cascade Control Approach -- 4.6.3 Explicit Constraint Handling Approach -- 4.7 Case Study: Forced Circulation Evaporator -- 4.7.1 Problem Description -- 4.7.2 DOF Analysis -- 4.7.3 Local Analysis -- 4.7.4 Selection of Measurement Subset as CVs.

4.7.5 Selection of Measurement Combinations as CVs -- 4.7.6 Comparison using Non-linear Analysis -- 4.7.7 CV Selection with Explicit Constraint Handling -- 4.8 Conclusions -- Acknowledgements -- References -- 5 Input-Output Pairing Selection for Design of Decentralized Controller -- 5.1 Introduction -- 5.1.1 State of the Art -- 5.2 Relative Gain Array and Variants -- 5.2.1 Steady-state RGA -- 5.2.3 The Dynamic RGA -- 5.2.4 The Effective RGA -- 5.2.5 The Block Relative Gain -- 5.2.6 Relative Disturbance Gain Array -- 5.3 μ-Interaction Measure -- 5.4 Pairing Analysis Based on the Controllability and Observability -- 5.4.1 The Participation Matrix -- 5.4.2 The Hankel Interaction Index Array -- 5.4.3 The Dynamic Input-Output Pairing Matrix -- 5.5 Input-Output Pairing for Uncertain Multivariable Plants -- 5.5.1 RGA in the Presence of Statistical Uncertainty -- 5.5.2 RGA in the Presence of Norm-Bounded Uncertainties -- 5.5.3 DIOPM and the Effect of Uncertainty -- 5.6 Input-Output Pairing for Non-linear Multivariable Plants -- 5.6.1 Relative Order Matrix -- 5.6.2 The Non-linear RGA -- 5.7 Conclusions -- References -- 6 Heuristics for Plantwide Control -- 6.1 Introduction -- 6.2 Basics of Heuristic Plantwide Control -- 6.2.1 Plumbing -- 6.2.2 Recycle -- 6.2.2.1 Effect of Recycle on Time Constants -- 6.2.2.2 Snowball Effects in Liquid Recycle Systems -- 6.2.2.3 Gas Recycle Systems -- 6.2.3 Fresh Feed Introduction -- 6.2.3.1 Ternary Example -- 6.2.3.2 Control Structures -- 6.2.3.3 Ternary Process with Altered Volatilities -- 6.2.4 Energy Management and Integration -- 6.2.5 Controller Tuning -- 6.2.5.1 Flow and Pressure Control -- 6.2.5.2 Level Control -- 6.2.5.3 Composition and Temperature Control -- 6.2.5.4 Interacting Control Loops -- 6.2.6 Throughput Handle -- 6.3 Application to HDA Process -- 6.3.1 Process Description.

6.3.2 Application of Plantwide Control Heuristics -- 6.3.2.1 Throughput Handle -- 6.3.2.2 Maximum Gas Recycle -- 6.3.2.3 Component Balances (Downs Drill) -- 6.3.2.4 Flow Control in Liquid Recycle Loop -- 6.3.2.5 Product Quality and Constraint Loops -- 6.4 Conclusions -- References -- 7 Throughput Manipulator Selection for Economic Plantwide Control -- 7.1 Introduction -- 7.2 Throughput Manipulation, Inventory Regulation and Plantwide Variability Propagation -- 7.3 Quantitative Case Studies -- 7.3.1 Case Study I: Recycle Process -- 7.3.1.1 Alternative Control Structures -- 7.3.1.2 Quantitative Back-off Results -- 7.3.1.3 Salient Observations -- 7.3.2 Case Study II: Recycle Process with Side Reaction -- 7.3.2.1 Economically Optimal Process Operation -- 7.3.2.2 Self-optimizing Variables for Unconstrained Degrees of Freedom -- 7.3.2.3 Plantwide Control System Design -- 7.3.2.4 Dynamic Simulation Results -- 7.4 Discussion -- 7.5 Conclusions -- Acknowledgements -- Supplementary Information -- References -- 8 Influence of Process Variability Propagation in Plantwide Control -- 8.1 Introduction -- 8.2 Theoretical Background -- 8.3 Local Unit Operation Control -- 8.3.1 Heat Exchanger -- 8.3.2 Extraction Process -- 8.4 Inventory Control -- 8.4.1 Pressure Control in Gas Headers -- 8.4.2 Parallel Unit Operations -- 8.4.3 Liquid Inventory Control -- 8.5 Plantwide Control Examples -- 8.5.1 Distillation Column Control -- 8.5.2 Esterification Process -- 8.6 Conclusions -- References -- Part 3 Methodologies -- 9 A Review of Plantwide Control Methodologies and Applications -- 9.1 Introduction -- 9.2 Review and Approach-based Classification of PWC Methodologies -- 9.2.1 Heuristics-based PWC Methods -- 9.2.2 Mathematical-based PWC Methods -- 9.2.3 Optimization-based PWC Methods -- 9.2.4 Mixed PWC Methods -- 9.3 Structure-based Classification of PWC Methodologies.

9.4 Processes Studied in PWC Applications -- 9.5 Comparative Studies on Different Methodologies -- 9.6 Concluding Remarks -- References -- 10 Integrated Framework of Simulation and Heuristics for Plantwide Control System Design -- 10.1 Introduction -- 10.2 HDA Process: Overview and Simulation -- 10.2.1 Process Description -- 10.2.2 Steady-state and Dynamic Simulation -- 10.3 Integrated Framework Procedure and Application to HDA Plant -- 10.3.1 Level 1.1: Define PWC Objectives -- 10.3.1.1 Application to HDA Process -- 10.3.2 Level 1.2: Determine CDOF -- 10.3.2.1 Application to HDA Process -- 10.3.3 Level 2.1: Identify and Analyze Plantwide Disturbances -- 10.3.3.1 Application to HDA Process -- 10.3.4 Level 2.2: Set Performance and Tuning Criteria -- 10.3.4.1 Application to HDA Process -- 10.3.5 Level 3.1: Production Rate Manipulator Selection -- 10.3.5.1 Application to HDA Process -- 10.3.6 Level 3.2: Product Quality Manipulator Selection -- 10.3.6.1 Application to HDA Process -- 10.3.7 Level 4.1: Selection of Manipulators for More Severe Controlled Variables -- 10.3.7.1 Application to HDA Process -- 10.3.8 Level 4.2: Selection of Manipulators for Less Severe Controlled Variables -- 10.3.8.1 Application to HDA Process -- 10.3.9 Level 5: Control of Unit Operations -- 10.3.9.1 Application to HDA Process -- 10.3.10 Level 6: Check Component Material Balances -- 10.3.10.1 Application to HDA Process -- 10.3.11 Level 7: Effects due to Integration -- 10.3.11.1 Application to HDA Process -- 10.3.12 Level 8: Enhance Control System Performance (if Possible) -- 10.3.12.1 Application to HDA Process -- 10.4 Evaluation of the Control System -- 10.5 Conclusions -- Appendix 10A -- References -- 11 Economic Plantwide Control -- 11.1 Introduction -- 11.2 Control Layers and Timescale Separation -- 11.3 Plantwide Control Procedure -- 11.4 Degrees of Freedom for Operation.

11.5 Steady-state DOFs -- 11.5.1 Valve Counting -- 11.5.2 Potential Steady-state DOFs -- 11.6 Skogestad's Plantwide Control Procedure: Top-down -- 11.6.1 Step S1: Define Operational Objectives (Cost J and Constraints) -- 11.6.2 Step S2: Determine the Steady-state Optimal Operation -- 11.6.2.1 Mode I: Given Throughput (Buyer's Market) -- 11.6.2.2 Mode II: Maximum Throughput (Seller's Market) -- 11.6.3 Step S3: Select Economic (Primary) Controlled Variables, CV1 (Decision 1) -- 11.6.3.1 CV1-rule 1 -- 11.6.3.2 CV1-rule 2 -- 11.6.3.3 Qualitative Approaches -- 11.6.3.4 Quantitative Approaches -- 11.6.3.5 Regions and Switching -- 11.6.4 Step S4: Select the Location of TPM (Decision 3) -- 11.6.4.1 Where should the TPM be Located? -- 11.6.4.2 Moving the TPM During Operation -- 11.7 Skogestad's Plantwide Control Procedure: Bottom-up -- 11.7.1 Step S5: Select the Structure of Regulatory (Stabilizing) Control Layer -- 11.7.1.1 Step S5(a): Select Stabilizing CV2 (Decision 2). -- 11.7.1.2 Step S5(b): Select Inputs (Valves) for Controlling CV2 (Decision 4) -- 11.7.2 Step 6: Select Structure of Supervisory Control Layer -- 11.7.3 Step 7: Structure of Optimization Layer (RTO) (Related to Decision 1) -- 11.8 Discussion -- 11.9 Conclusions -- References -- 12 Performance Assessment of Plantwide Control Systems -- 12.1 Introduction -- 12.2 Desirable Qualities of a Good Performance Measure -- 12.3 Performance Measure Based on Steady State: Steady-state Operating Cost/Profit -- 12.4 Performance Measures Based on Dynamics -- 12.4.1 Process Settling Time Based on Overall Absolute Component Accumulation -- 12.4.2 Process Settling Time Based on Plant Production -- 12.4.3 Dynamic Disturbance Sensitivity (DDS) -- 12.4.4 Deviation from the Production Target (DPT) -- 12.4.5 Total Variation (TV) in Manipulated Variables.

12.5 Application of the PerformanceMeasures to the HDA Plant Control Structure.