ADVANCED PROCESS ANALYSIS SYSTEM VOL. I A Thesis Submitted to the Graduate Faculty of the Louisiana State University and Agriculture and Mechanical College in partial fulfillment of the requirements for the degree of Master of Science in Chemical Engineering in The Department of Chemical Engineering by Kedar Shivanand Telang B.S., Indian Institute of Technology, Bombay, 1996 December 1998 ACKNOWLEDGMENTS The author wishes to express his appreciation and gratitude to Professor Ralph W. Pike for giving him the opportunity to participate in this research work. His guidance and assistance are deeply appreciated. The examining committee members, Professor F. Carl Knopf and Professor Karsten Thompson are recognized for their efforts in reviewing and evaluating this research. The cooperation of engineers and managers of the IMC Agrico Company was invaluable in this research. The assistance of Mr. Thomas A. Hertwig of IMC Agrico is especially acknowledged for providing the detailed information and data for the sulfuric acid process. In addition, the assistance of Ms. Gayathri Srinivasan and Mr. Tai Lee in Visual Basic programming was invaluable. The financial support for this research by the Environment Protection Agency is gratefully acknowledged. Also, the Department of Chemical Engineering at Louisiana State University is recognized for its assistance and support. Finally, the author would like to acknowledge the support and encouragement of friends and family during his post graduate study. ii TABLE OF CONTENTS VOLUME I ACKNOWLEDGEMENTS..........................................................................................ii LIST OF TABLES .......................................................................................................vi LIST OF FIGURES......................................................................................................x ABSTRACT .................................................................................................................xvii CHAPTER 1 INTRODUCTION...................................................................................1 A. An Overview of the Advanced Process Analysis System ...............1 B. The Component Programs ...............................................................1 B-1. Flowsheeting.....................................................................1 B-2. Chemical Reactor Design Program ..................................3 B-3. Heat Exchanger Network Design .....................................4 B-4. Online Optimization .........................................................6 B-5. Pollution Assessment Module ..........................................7 C. Summary..........................................................................................8 2 LITERATURE REVIEW........................................................................9 A. Advanced Process Analysis System................................................9 B. Energy Conservation........................................................................10 B-1. Heuristic Approaches .......................................................11 B-2. Pinch Analysis..................................................................11 C. Concepts...........................................................................................11 C-1. Temperature Intervals.......................................................11 C-2. Heat Cascade Diagram .....................................................13 C-3. Grand Composite Curve...................................................13 C-4. Heat Recovery Pinch ........................................................13 C-5. Stream Grid Diagram .......................................................14 D. Targeting..........................................................................................14 D-1. Utility...............................................................................14 D-2. Number of Units...............................................................15 D-3. Heat Exchanger Area .......................................................16 D-4. Cost Target .......................................................................20 E. Design ..............................................................................................21 F. Mathematical Programming Methods..............................................24 F-1. Simultaneous Optimization and Heat Integration.............31 G. New Methods...................................................................................32 H. Pollution Prevention .......................................................................32 H-1. The Environmental Impact Theory ..................................33 I. Summary ...........................................................................................38 iii 3 THE METHODOLOGY.........................................................................39 A. The Flowsheeting Program..............................................................40 A-1. Formulation of Constraints for Process Units..................40 A-2. Classification of Variables and Determination of Parameters .......................................................................41 A-3. Flowsim............................................................................41 B. The Online Optimization Program ..................................................43 B-1. Combined Gross Error Detection And Data Reconciliation..................................................................44 B-2. Simultaneous Data Reconciliation and Parameter Estimation........................................................................45 B-3. Plant Economic Optimization...........................................46 C. The Chemical Reactor Analysis Program........................................47 D. The Heat Exchanger Network Program...........................................48 E. The Pollution Index Program...........................................................51 F. Summary ..........................................................................................53 4 PROCESS MODELS..............................................................................55 A. D-Train Contact Sulfuric Acid Process Description .......................55 B. E-Train Contact Sulfuric Acid Process Description........................60 C. Process Model for D-Train Sulfuric Acid Process ..........................64 C-1. Heat Exchanger Network .................................................65 C-2. Reactor Section.................................................................71 C-3. Absorption Tower Section................................................80 C-4. Overall Material Balance..................................................82 D. Process Model Validation................................................................83 5 RESULTS................................................................................................89 A. The D-train Sulfuric Acid Process...................................................89 A-1. Flowsim............................................................................89 A-1-1. Measured Variables ..........................................90 A-1-2. Unmeasured Variables......................................92 A-1-3. Parameters.........................................................92 A-1-4. Equality Constraints..........................................93 A-1-5. Inquality Constraints.........................................94 A-1-6. Constants...........................................................94 A-1-7. Tables................................................................95 A-1-8. Enthalpies..........................................................95 A-2. On-line Optimization........................................................96 A-3. Heat Exchanger Network Optimization ...........................101 A-4. Pollution Index Program ..................................................107 B. The E-train Sulfuric Acid process ...................................................110 B-1. Heat Exchanger Network Optimization ...........................110 B-2. Pollution Index Calculations ............................................115 iv C. Comparison of D-Train and E-Train Processes...............................115 D. Summary..........................................................................................118 6 CONCLUSIONS AND RECOMMENDATIONS..................................119 A. Conclusions .....................................................................................119 B. Recommendations............................................................................120 REFERENCES .............................................................................................................122 APPENDICES A. PHYSICAL PROPERTIES OF PROCESS STREAMS ...................126 B. KINETIC MODEL FOR CATALYTIC OXIDATION OF SO2 TO SO3 ...............................................................................134 VOLUME II C. ADVANCED PROCESS ANALYSIS SYSTEM USER’S MANUAL AND TUTORIAL ............................................141 VITA.............................................................................................................................459 v LIST OF TABLES Table 4.1 Process Units in the D-Train Sulfuric Acid Process Model .........67 Table 4.2 Process Streams in the D-Train Sulfuric Acid Process Model .....68 Table 4.3 The Constraint Equations for Hot Inter-Pass Heat Exchanger .....70 Table 4.4 The Process Constraint Equations