Hysys Unit Operations v10 Reference Guide

Aspen HYSYS Unit Operations

Reference Guide

Version Number: V10 June 2017 Copyright (c) 1981-2017 by Aspen Technology, Inc. All rights reserved. Aspen Plus®, Aspen Air Cooled Exchanger™, AirCooled™, Aspen Rate-Based Distillation™, Aspen Custom Modeler®, Aspen HTFS Research Network™, Aspen HYSYS®, Aspen HYSYS Petroleum Refining®, Aspen Process Economic Analyzer, Aspen In-Plant Cost Estimator, Aspen Capital Cost Estimator, Aspen OnLine®, Aspen PIMS™, Aspen Plus Optimizer™, Aspen Process Manual™, Aspen Properties®, Aspen Shell & Tube Exchanger™, Shell&Tube™, SLM™, and the Aspen leaf logo are trademarks or registered trademarks of Aspen Technology, Inc., Burlington, MA. All other brand and product names are trademarks or registered trademarks of their respective companies. This document is intended as a guide to using AspenTech's software. This documentation contains AspenTech proprietary and confidential information and may not be disclosed, used, or copied without the prior consent of AspenTech or as set forth in the applicable license agreement. Users are solely responsible for the proper use of the software and the application of the results obtained. Although AspenTech has tested the software and reviewed the documentation, the sole warranty for the software may be found in the applicable license agreement between AspenTech and the user. ASPENTECH MAKES NO WARRANTY OR REPRESENTATION, EITHER EXPRESSED OR IMPLIED, WITH RESPECT TO THIS DOCUMENTATION, ITS QUALITY, PERFORMANCE, MERCHANTABILITY, OR FITNESS FOR A PARTICULAR PURPOSE. Aspen Technology, Inc. 20 Crosby Drive Bedford, MA 01730 USA Phone: (1) (781) 221-6400 Toll Free: (1) (888) 996-7100 URL: http://www.aspentech.com

Contents

Contents 1 Unit Operations Overview About this Guide Integrated Steady State and Dynamics Simulation Multi-Flowsheet Architecture Extensibility and Customization Model Categories Degrees of Freedom Adding Unit Operations Basic Unit Operation Property View Object Inspect Menu Logical Connections For... Property View 2 Unit Operation Common Property Views Graph Control Property View Heat Exchanger Page Duty Radio Button Options Heater Type Group Duty Source/Source Group Tube Bundle Radio Button Holdup Page Holdup Property View Nozzles Page Notes Pages or Tabs Notes Manager Holdup Model Assumptions of Holdup Model Accumulation Non-Equilibrium Flash Heat Loss Model Chemical Reactions Related Calculations Advanced Holdup Properties Stripchart Page Adding a Strip Chart from the Navigation Pane or Ribbon

Contents

iii 1 1 2 2 3 3 4 5 11 12 12 15 15 16 16 16 17 18 21 22 22 23 23 24 24 25 25 28 31 31 32 34 34

iii

Adding a Strip Chart from a Unit Operation Using the Data Logger Property View Controls in the Displayed Strip Chart User Variables Page Adding a User Variable Variable Navigator (Multi-Select) Variable Navigator (Single-Select) Select Type Dialog Box Using the Select Type Dialog Box Changing the Fluid Package for Multiple Unit Operations Worksheet Tab Stream Conditions Stream Properties Stream Compositions PF Specs 3 Column Input Experts Column Reboiler Pre-configurations Reboiler Once-Through Reboiler Circulation Without Baffle Reboiler Circulation With Baffle Reboiler Circulation with Auxiliary Baffle Absorber Distillation Column Liquid-Liquid Extractor Reboiled Absorber Refluxed Absorber Three Phase Distillation 4 Side Operations Input Expert Reboiled Side Stripper Steam Stripped Side Stripper Side Rectifier Pump-Around Vapor Bypass 5 Column Operations Using Column Subflowsheets Isolation of the Column Solver Independent Fluid Package Ability to Construct Custom Column Configurations Use of Simultaneous Solution Algorithm Dynamic Mode Column Property View Main Flowsheet and Column Subflowsheet Relationship Main Flowsheet / Subflowsheet Concept HYSYS Column Theory Three Phase Theory

iv

34 35 35 37 38 39 40 41 42 42 42 43 43 43 43 45 45 46 47 48 48 50 52 55 57 59 62 65 66 68 70 72 74 77 77 78 78 79 79 79 80 81 81 82 86

Contents

Basic Column Parameters Pressure Flow Condensers and Reboilers Column Installation Input Experts Templates Column Specification Types Cold Property Specifications Component Flow Rate Component Fractions Component Ratio Component Recovery Cut Point Draw Rate Delta T (Heater/Cooler) Delta T (Streams) Duty Duty Ratio Feed Ratio Gap Cut Point Liquid Flow Physical Property Specifications Pump Around Specifications Reboil Ratio Recovery Reflux Feed Ratio Reflux Fraction Ratio Reflux Ratio Stream Property Tee Split Fraction Tray Temperature Transport Property Specifications User Property Vapor Flow Vapor Fraction Vapor Pressure Specifications Column Stream Specifications Column-Specific Operations Condenser Unit Operation Reboiler Unit Operation Column Tower Tee Running the Column Run Reset Column Troubleshooting Heat and Spec Errors Fail to Converge Equilibrium Error Fails to Converge Equilibrium Error Oscillates

Contents

88 89 93 95 96 97 103 103 103 104 104 105 105 106 106 106 107 107 107 108 109 109 109 110 110 111 111 111 112 113 113 114 114 114 115 115 115 116 117 130 139 151 152 152 153 154 154 157 157

v

References 6 Column Property View Column Runner Column Convergence Sequence Design Tab Connections Page (Main Flowsheet) Tower Details Property View Connections Page (Column Runner) Monitor Page Specs Page Specification Property View Advanced Solving Options Specs Summary Page Subcooling Page Notes Page Parameters Tab Profiles Page Estimates Page Efficiencies Page Solver Page Col Dynamic Estimates Property View 2/3 Phase Page Fluid Pkgs Page Amines Page Side Ops Tab Side Strippers Page Side Rectifiers Page Pump Arounds Page Vap Bypasses Page Side Draws Page Internals Tab Rating Tab Towers Page Vessels Page Equipment Page Pressure Drop Page Worksheet Tab Performance Tab Summary Page Column Profiles Page Feeds/Products Page Plots Page Properties View for Plots and Tables Data Control Property View Condenser/Reboiler Page Flowsheet Tab Setup Page Flowsheet Variables Page (Main)

vi

158 159 159 160 160 160 162 163 163 167 168 169 172 172 172 172 173 174 175 178 186 188 190 190 192 193 194 194 194 195 195 196 197 198 198 198 199 199 200 200 200 201 215 216 218 218 218 220

Contents

Internal Streams Page Mapping Page Lock Page Reactions Tab Stages Page Column Reaction Property View Results Page Dynamics Tab Vessels Page Equipment Page Holdup Page Perturb Tab Column Internals Tab Adding a New Internals Option Creating Column Sections Duplicating Column Sections Using Auto Sectioning Selecting an Active Option Adding a New Geometry Option Updating Pressure Drops Calculating the Pressure Drop Across a Sump Including Static Vapor Head Correction Viewing Internals Summary Results Initializing from the Rating Tab Sending to the Rating Tab Importing and Exporting Column Section Templates Viewing Internals Results 7 Column Analysis Overview Column Analysis Workflow Column Internals Manager Column Design Ribbon Column Analysis Flowsheet Icons Removing Column Analysis Flowsheet Icons Creating a Column Internals Configuration Creating Column Sections Duplicating Column Sections Using Auto Sectioning Updating Pressure Drops Calculating the Pressure Drop Across a Sump Including Static Vapor Head Correction Viewing Internals Summary Results Initializing from the Rating Tab Sending to the Rating Tab Importing Column Section Templates Exporting Column Section Templates Geometry Details Tray Geometry Workflow Packing Geometry Workflow

Contents

221 222 222 222 224 224 226 227 228 228 228 228 229 230 230 233 234 234 234 234 235 235 236 236 236 237 238 241 241 242 243 243 246 246 247 250 251 252 252 253 253 253 254 254 255 255 255 256

vii

Specifying Tray Geometry Specifying Picket Fence Weirs or Swept Back Weirs Viewing the Tray Geometry Summary Specifying Tray Geometry Design Parameters Viewing Tray Summary Results Viewing Tray Geometry Results By Tray Specifying Packing Geometry Specifying Packing Geometry Design Parameters Specifying Packing Constants Viewing Packing Summary Results Viewing Packing Results By Stage Geometry Messages Hydraulic Plots Accessing Hydraulic Plots Trayed Hydraulic Plots Packing Hydraulic Plots Hydraulic Plots Ribbon Tab Importing Column Analysis Variables into a Spreadsheet Exporting Column Results to Vendor Packages Using Column Analysis Report Builder Methods Used in Column Analysis Swept-Back Weir Calculations Chan and Prince Dump Point Correlation Liquid Entrainment Correlations Discharge Coefficient Downcomer Relative Froth Density Tray and Downcomer Area Calculations Downcomer Backup Calculations Maximum Capacity Calculations for Packing Liquid Holdup Calculations for Packing Foaming Calculations Packing Types and Packing Factors Downcomer Choke Flooding Flooding Calculations for Trays Kister & Haas Jet Flood Correlation Fair and Fair72 Jet Flood Correlations Smith, Dresser, and Ohlswager Jet Flood Correlation Pressure Drop Calculations for Packing in Column Analysis Sherwood/Leva/Eckert GPDC Pressure Drop Correlation for Packing Aspen GPDC85 Pressure Drop Correlation for Packing Wallis Pressure Drop Correlation for Packing Billet-99 Correlation for Packing Pressure Drop Calculations for Trays 8 Electrolyte Operations Introduction Electrolyte Operations

viii

256 281 284 284 288 290 293 294 297 298 298 300 300 300 301 304 306 308 308 310 312 312 312 313 315 316 318 325 326 328 328 331 331 332 333 334 336 337 338 341 343 347 348 351 351 351

Contents

9 Crystallizer Operation Theory Boundary Condition Equations Design Tab Connections Page Parameters Page Solver Page User Variables Page Notes Page Rating Tab Worksheet Tab Dynamics Tab 10 Neutralizer Operation Theory Boundary Condition Solving Options Equations Design Tab Connections Page Parameters Page Solver Page Rating Tab Dynamic Tab 11 Precipitator Operation Theory Boundary Condition Solving Options Equations Design Tab Connections Page Parameters Page Solver Page User Variables Page Notes Page Rating Tab Worksheet Tab Dynamic Tab

353 353 354 354 354 355 355 356 356 356 357 357 357 359 359 360 360 360 361 361 361 362 362 363 365 365 366 366 366 367 367 367 368 368 368 369 369 369

12 Heat Transfer Operations

371

13 Air Cooler

373

Theory Steady State Rigorous Air Cooler Functionality Dynamics

Contents

373 373 374 374

ix

Heat Transfer Dynamic Specifications Pressure Drop Air Cooler Property View Design Tab Connections Page Parameters Page Specs Page User Variables Page Notes Page Rating Tab Sizing Page (Simple Design) Sizing Page Rigorous Air Cooler Nozzles Page Worksheet Tab Performance Tab Performance Results Page Performance Profiles Page Performance Plots Page Performance Tables Page Performance Setup Page Dynamics Tab Model Page Specs Page Holdup Page Stripchart Page Rigorous Air Cooler Tab Simulation Calculation Options Exchanger Page Process Data Page Property Range Page Results Summary Page Setting Plan Page Tube Layout Page Profiles Page 14 Cooler/Heater Theory Steady State Operation Dynamic Operation Pressure Drop Dynamic Specifications Heater or Cooler Property View Design Tab Connections Page Parameters Page User Variables Page Notes Page Rating Tab

x

374 375 375 376 376 377 377 378 378 378 378 378 379 380 380 380 380 381 381 381 382 382 382 383 384 385 385 385 386 386 387 388 389 389 389 391 391 391 391 392 392 393 393 393 393 394 394 394

Contents

Nozzles Page Heat Loss Page Worksheet Tab Performance Tab Profiles Page Plots Page Tables Page Setup Page Dynamics Tab Specs Page Duty Fluid Page Holdup Page Stripchart Page

394 394 395 395 396 396 396 397 397 398 400 401 401

15 Fired Heater (Furnace)

403

Fired Heater Steady State Operation Fired Heater Dynamic Operation Switching Modes Fired Heater Theory Combustion Reaction Heat Transfer Radiant Heat Transfer Convective Heat Transfer Conductive Heat Transfer Pressure Drop Minimum Specifications Fired Heater Property View Design Tab Connections Page Parameters Page User Variables Page Notes Page Rating Tab Sizing Page Nozzles Page Heat Loss Page Worksheet Tab Performance Tab Performance Details Page Performance Plots Page Performance Tables Page Performance Setup Page Dynamics Tab Tube Side PF Page Flue Gas PF Page Holdup Page EDR Fired Heater Tab Summary Page Streams Page

Contents

404 405 405 405 405 406 409 409 410 410 411 411 411 412 412 413 413 413 413 417 417 417 417 417 417 418 418 418 418 419 420 420 420 421

xi

Fuel Page Flue Gas Page Tube Banks Page Operation Page Property Table Page 16 Heat Exchanger Heat Exchanger Theory Steady State Dynamic Pressure Drop Dynamic Specifications Heat Exchanger Property View Design Tab Connections Page Parameters Page Specs Page Specification Property View User Variables Page Notes Page Worksheet Tab Heat Exchanger Rating Tab Sizing Page Parameters Page Detailed Heat Model Properties Property View Nozzles Page Heat Loss Page Performance Tab Details Page Plots Page Tables Page Setup Page Error Msg Page Dynamics Tab Model Page Specs Page Holdup Page Stripchart Page Rigorous Shell&Tube Tab Specifying Application Information for Rigorous Shell&Tube Specifying Exchanger Information for Rigorous Shell&Tube Specifying Process Information for Rigorous Shell&Tube Specifying Property Ranges for Rigorous Shell&Tube Viewing Results Summary for Rigorous Shell&Tube Viewing a Setting Plan for Rigorous Shell&Tube Viewing Tube Layout Information for Rigorous Shell&Tube Viewing Rigorous Shell&Tube Profiles Information Specifying Find Fouling Calculation Options for Rigorous Shell&Tube

xii

421 421 421 421 421 423 424 424 425 425 426 426 427 427 427 432 433 436 436 437 437 437 441 445 448 448 448 449 451 451 451 452 452 452 455 458 459 459 460 462 468 469 470 470 471 472 472

Contents

17 Liquefied Natural Gas (LNG) Exchanger Theory Heat Transfer Pressure Drop Convective (U) & Overall (UA) Heat Transfer Coefficients Dynamic Specifications LNG Property View Design Tab Connections Page Parameters Page Specs Page Specification Property Views User Variables Page Notes Page Rating Tab Sizing (dynamics) Page Layers (dynamic) Page Heat Transfer (dynamics) Page Worksheet Tab Performance Tab Results Page Plots Page Tables Page Setup Page Summary Page Layers Page Dynamics Tab Model Page Specs Page Holdup Page Estimates Page Stripchart Page About the LNG Wound Coil Heat Exchanger Wound Coil Heat Exchanger (WCHE) Reference Page Wound Coil Heat Exchanger - Plate Fin Equivalents Reference LNG EDR PlateFin Overview EDR PlateFin Tab Exchanger Design Ribbon Options EDR PlateFin Process Page EDR PlateFin Property Ranges Page EDR PlateFin Results Summary Page EDR PlateFin Results Geometry LNG EDR CoilWound Overview EDR CoilWound Tab Exchanger Design Ribbon Options Specifying LNG EDR CoilWound Process Information Specifying LNG EDR CoilWound Property Ranges Viewing LNG EDR CoilWound Results Summary Viewing LNG EDR CoilWound Results Geometry

Contents

475 476 476 477 477 478 479 479 479 479 481 482 484 484 484 485 486 487 489 489 489 491 491 492 492 493 493 493 495 496 497 497 497 498 500 507 508 508 509 511 512 513 515 516 516 517 519 520 522

xiii

Modifying LNG EDR CoilWound Convergence Parameters References

523 524

18 Plate Exchanger

525

Theory

525 525 526 526 526 527 527 528 528 529 530 531 532 532

Heat Transfer Plate Exchanger Design Tab Specifying Plate Exchanger Connections Specifying Plate Exchanger Parameters Plate Exchanger Specifications Rigorous Plate Overview EDR Rigorous Plate Tab Exchanger Design Ribbon Options Specifying Rigorous Plate Process Information Specifying Rigorous Plate Property Ranges Viewing Rigorous Plate Results Summary Viewing Rigorous Plate Setting Plan Viewing Rigorous Plate Profiles 19 Logical Operations Common Options ATV Tuning Technique Controller Face Plate 20 Adjust Operation Connections Tab Connections Page Notes Page Parameters Tab Parameters Page Simultaneous Adjust Manager Options Page Monitor Tab Tables Page Plots Page User Variables Tab Starting the Adjust Individual Adjust Multiple Adjust 21 Balance Balance Property View Connections Page Parameters Tab Worksheet Tab Stripchart Tab User Variables Tab

xiv

533 533 533 534 537 537 538 538 539 539 540 542 543 543 543 543 544 544 545 547 548 548 548 552 552 552

Contents

22 Boolean Operations Boolean Logic Blocks Property View Logical Operation Face Plate Property View Boolean Connections Tab Adding/Editing Process Variable (PV) Source Adding/Editing Output Target Boolean Monitor Tab Not Gate Xor Gate On Delay Gate Off Delay Gate Latch Gate Counter Up Gate Counter Down Gate Boolean And Gate Specifying Boolean And Gate Connections Monitoring Boolean And Gate Input and Output Values Boolean Or Gate Specifying Boolean Or Gate Connections Monitoring Boolean Or Gate Input and Output Values Cause and Effect Matrix Configuring a Cause and Effect Matrix Connecting the Inputs Connecting the Outputs Changing the Order of the Inputs or Outputs Viewing the Inputs and Outputs Specifications Viewing Status Messages Viewing Trace Messages

553 554 554 555 555 555 556 556 556 557 557 558 559 559 560 560 561 561 562 562 563 564 565 567 568 568 569 570

23 Control Ops

571

24 Split Range Controller

573

Connections Tab Parameters Tab Operation Page Configuration Page Advanced Page Autotuning Page IMC Design Page Scheduling Page Alarms Page Signal Processing Page Initialization Page Split Range Setup Tab Stripchart Tab User Variables Tab

Contents

574 574 575 576 577 581 582 583 583 584 585 585 586 586

xv

25 Ratio Controller Connections Tab Parameters Tab Configuration Page Range Page Advanced Page Autotuning Page IMC Design Page Scheduling Page Alarms Page Signal Processing Page Initialization Page Stripchart Tab User Variables Tab 26 PID Controller Connections Tab Process Variable Source Remote Setpoint Source Output Target Object Parameters Tab Configuration Page Advanced Page Autotuner Page IMC Design Page Scheduling Page Alarms Page PV Conditioning Page Signal Processing Page FeedForward Page Model Testing Page Initialization Page Monitor Tab Stripchart Tab User Variables Tab Algorithm References HYSYS PID Controller Algorithms Foxboro PID Controller Algorithms Discrete Time Domain Implementation of the Foxboro Algorithms Honeywell PID Controller Algorithms Discrete Time Domain Implementation of the Honeywell Algorithms Yokogawa PID Controller Algorithms 27 MPC Controller Connections Tab Process Variable Source Remote Setpoint Output Target Object

xvi

587 588 588 589 591 592 595 596 597 597 598 599 599 600 601 602 602 602 603 603 603 608 611 614 614 615 616 618 619 619 620 620 621 621 621 621 623 624 626 627 629 631 632 632 632 633

Contents

Parameters Tab Operation Page Configuration Page Advanced Page Alarms Page Signal Processing Page MPC Setup Tab Basic Page Advanced Page Process Models Tab Basic Page Advanced Page Stripchart Tab User Variables Tab 28 DMCplus Controller Connections Tab Controlled Variable (CV) Manipulated Variable (MV) Feed Forward (FF) Model Test Tab Performing DMCplus Model Testing Operation Tab Operation Page FF Variable Page Stripchart Tab User Variables Tab Control Valve Window Control OP Port 29 Digital Point Connections Tab Parameters Tab Off Mode Manual Mode Auto Mode Stripchart Tab User Variables Tab Alarm Levels Tab 30 External Data Linker Connections Page Configuration Page Properties Page Revision History Tab 31 Recycle Recycle Property View

Contents

633 633 634 635 637 639 639 640 641 643 643 644 644 644 645 647 647 647 648 648 650 652 652 653 654 654 654 656 657 657 658 658 658 659 661 662 662 663 663 663 664 664 665 666

xvii

Connections Tab Connections Page Notes Page Parameters Tab Variables Page Numerical Page Convergence Page Worksheet Tab Monitor Tab User Variables Tab Calculations Reducing Convergence Time Recycle Advisor Using the Recycle Advisor Recycle Setup Tab 32 Selector Block Connections Tab Parameters Tab Selection Mode Page Scaling Factors Page Monitor Tab Stripchart Tab User Variables Tab 33 Set

677 677 678 678 680 680 681 681 683

Set Property View Connections Tab Parameters Tab User Variables Tab 34 Spreadsheet Spreadsheet Functions General Math Functions Calculation Hierarchy Logarithmic Functions Trigonometric Functions Logical Operators IF/THEN/ELSE Statements Spreadsheet Interface Importing and Exporting Variables by drag and drop Enumeration in Spreadsheet Importing Variables by Browsing Exporting Formula Results View Associated Object Spreadsheet Tabs Connections Tab Parameters Tab

xviii

666 666 666 666 667 668 672 672 672 673 673 673 674 674 675

683 683 684 684 685 686 686 687 688 688 689 689 690 690 690 691 691 692 692 692 693

Contents

Formulas Tab Spreadsheet Tab Calculation Order Tab User Variables Tab Function Help and Spreadsheet Only Buttons 35 Stream Cutter Stream Cutter Property View Changing the Fluid Package Changing the Fluid Package in the Unit Operation Property View Changing the Fluid Package Using the Object Inspect Menu Changing the Fluid Package from the Fluid Package Manager Design Tab Connections Page Specifying Stream Cutter Transition Information Fluid Package Transitions True to Apparent Transition 36 Black Oil Translator Connections Tab Transitions Tab Simple Method Three Phase Method Infochem Multiflash Transition Types 37 Transfer Function Transfer Function Property View Connections Tab Parameters Tab Configuration Page Integrator Page Delay Page Lag Page Lead Page 2nd Order Page Ramp Page Rate Limiter Page Stripchart Tab User Variables Tab 38 Piping Operations Piping References 39 Compressible Gas Pipe Model for a Single Phase Compressible Flow Governing Equations

Contents

695 695 696 696 696 699 699 699 700 703 704 704 704 705 706 708 709 709 709 710 711 711 712 713 714 714 714 715 716 716 717 718 719 720 721 721 721 723 723 725 725 725

xix

Algorithm Compressible Gas Pipe Property View Design Tab Connections Page Parameters Page User Variables Page Notes Page Rating Tab Sizing Page Heat Transfer Page Worksheet Tab Performance Tab Profiles Page Properties Tab Dynamics Tab Specs Page Stripchart Page 40 Liquid-liquid Hydrocyclone Theory Oil Droplet Distribution Hydrocyclone Liner Dimensions Hydrocyclone Hydraulics Oil Droplet Migration Probability Hydrocyclone Separation Efficiency Liquid-liquid Hydrocyclone Property View Design Tab Connections Page Parameters Page Liner Details Page Droplet Distribution Page User Variables Page Notes Page Performance Tab General Page Geometric Page Overflow Page Underflow Page Tables Page Plots Page Worksheet Tab Dynamics Tab Nomenclature 41 Mixer Mixer Property View Design Tab Connections Page

xx

726 726 726 727 727 727 727 728 728 729 729 729 729 730 730 731 731 733 733 734 734 735 737 738 738 739 739 739 741 742 743 743 743 743 743 743 744 744 744 744 744 744 747 748 748 748

Contents

Parameters Page User Variables Page Notes Page Rating Tab Nozzles Page Worksheet Tab Dynamics Tab Specs Page Holdup Page Stripchart Page 42 Pipe Segment Calculation Modes Pressure Drop Mode Length Mode Diameter Mode Flow Mode Incremental Material and Energy Balances Mode Pipe Segment Property View Design Tab Connections Page Parameters Page Summary of Methods Emulsions Page User Variables Page Notes Page Pipe Segment Rating Tab Sizing Page Pipe Fittings Property View Dynamics Tab Parameters Page Holdup Page Stripchart Page Rating Tab Heat Transfer Page Pipe Segment Heat Model Page Pipe Segment Performance Tab Profiles Page Pipe Profile View Property View Insulation Page Pipe Segment Performance Tab (Dynamics Mode) Viewing Segments Performance Results Viewing Holdups Performance Results HYSYS Piping Flow Assurance Pipe Flow Assurance - CO2 Corrosion Pipe Flow Assurance - Erosion Pipe Flow Assurance - Hydrates Specifying P/T Options: Hydrate Formation Profile Pipe Flow Assurance - Slug Analysis

Contents

748 749 749 749 749 749 749 750 750 751 753 753 754 755 756 756 757 758 758 758 759 760 787 787 787 787 788 798 801 801 802 802 803 803 809 816 816 816 818 819 819 820 820 821 823 823 824 825

xxi

Pipe Flow Assurance - Wax Deposition Profes Wax Property View References CO2 Corrosion Rate Correlations Reference Pipe Flow Correlations Fitting Pressure Loss Pipe Emulsion Viscosity Methods 43 Relief Valve Design Tab Connections Page Parameters Page User Variables Page Notes Page Rating Tab Sizing Page Nozzles Page Worksheet Tab Dynamics Tab Specs Page Holdup Page Advanced Page Stripchart Page 44 Tee Tee Property View Design Tab Connections Page Parameters Page User Variables Page Notes Page Rating Tab Nozzles Page Dynamics Tab Specs Page Holdup Page Stripchart Page 45 Valve Operation Valve Property View Design Tab Connections Page Parameters Page User Variables Page Notes Page Rating Tab Sizing Page Characteristic Curve Property View

xxii

828 831 838 838 843 844 846 851 851 851 852 852 852 852 853 856 856 856 856 857 858 858 859 859 859 859 860 861 861 861 861 861 861 862 863 865 866 866 866 866 867 867 867 867 873

Contents

Control Valve Calculation Theory Nozzles Page Options Page Flow Limits Page Worksheet Tab Dynamics Tab Specs Page Pipe Page Holdup Page Actuator Page Flow Limits Page Stripchart Page

874 890 890 890 890 891 891 893 894 895 897 899

46 Reactor Operations

901

47 Reactor Operations: CSTR and General Reactors

903

General Reactors Property Views Design Tab Connections Page Parameters Page Conversion Reactor Reactions Tab Details Page Results Page CSTR Reactions Tab Details Page Results Page Equilibrium Reactor Reactions Tab Details Page Results Page Gibbs Reactor Reactions Tab Overall Page Details Page Rating Tab Sizing Page Nozzles Page Heat Loss Page Worksheet Tab Dynamics Tab Specs Page Holdup Page Stripchart Page Heat Exchanger Page 49 Yield Shift Reactor Theory Product Stream Mass Fractions Yield Shift Reactor Property View Design Tab Connections Page

Contents

905 905 905 906 908 908 909 911 911 912 913 914 915 916 917 917 918 918 921 921 921 921 922 923 924 924 925 925 925 927 927 927

xxiii

Parameters Page Model Config Tab Design Parameters Page Design Variables Page Heat of Reaction Page Composition Shift Tab Design Data Page Design Data: Base Page Design Data: Datasets Page Base Yields Page Base Shifts Page Efficiencies Page Results Page Property Shift Tab Properties Page Design Data Page Design Data: Base Page Design Data: Datasets Page Base Shifts Page Efficiencies Page Results Page Worksheet Tab Dynamics Tab Specs Page 50 Plug Flow Reactor Newton’s Method Plug Flow Reactor (PFR) Property View PFR Design Tab Connections Page Parameters Page Heat Transfer Page User Variables Page Notes Page Reactions Tab Overall Page Details Page Results Page Rating Tab Sizing Page Nozzles Page Worksheet Tab Performance Tab Conditions Page Flows Page Reaction Rates Page Transport Page Compositions Page Dynamics Tab

xxiv

928 928 929 929 930 930 931 931 933 935 936 937 937 937 938 939 939 939 940 940 940 941 941 941 943 943 945 945 946 946 948 950 951 951 951 953 954 955 955 956 957 957 957 958 958 958 959 959

Contents

Specs Page Holdup Page Duty Page Stripchart Page

959 961 961 961

51 Rotating Equipment

963

References

963

52 Centrifugal Compressor or Expander Unit Operations Typical Solution Methods Compressor - Expander Theory Steady State Dynamics Equations Used Compressor Efficiencies Expander Efficiencies Compressor Heads Expander Heads Using Momentum Equations References Methods Used Compressor Performance Curves: Off Design Corrections Compressor Curve Interpolation Details Huntington Method Multiple IGV Curves Multiple MW Curves Quasi-Dimensionless and Non-Dimensional Curves Schultz Method Reference Compressor - Reference Method Single Curve Compressor Options Compressor or Expander Design Tab Connections Page Parameters Page Surge Analysis Links Page User Variables Page Notes Page Compressor or Expander Rating Tab Curves Page Flow Limits Page Nozzles Page Inertia Page Electric Motor Page Compressor or Expander Performance Tab Results Page Power Page Compressor or Expander Dynamics Tab Specs Page

Contents

965 966 967 967 968 969 969 970 971 971 972 973 973 973 976 977 978 980 981 984 985 985 986 986 987 988 988 989 990 990 990 997 998 999 999 1002 1003 1003 1003 1004

xxv

Surge Controller Holdup Page Stripchart Page

1006 1009 1009

53 Reciprocating Compressor Unit Operation

1011

Reciprocating Compressor Theory Rod Loading Maximum Pressure Flow Reciprocating Compressor Design Tab Connections Page Parameters Page Links Page Settings Page User Variables Page Notes Page Reciprocating Compressor Rating Tab Nozzles Page Inertia Page Reciprocating Compressor Performance Tab Results Page Power Page Reciprocating Compressor Dynamics Tab

1012 1014 1015 1015 1015 1016 1016 1016 1016 1017 1017 1018 1018 1018 1018 1018 1019 1019

54 Screw Compressor Workflow Screw Compressor Theory Volumetric Efficiency and Leakage Flow Calculation Performance Curve Calculation References Screw Compressor: Design Tab Connections Page Parameters Page Links Page Settings Page Screw Compressor: Rating Tab Curves Page Nozzles Page Inertia Page Screw Compressor: Performance Tab Results Page Power Page Screw Compressor: Dynamics Tab Specs Page Holdup Page Stripchart Page

xxvi

1021 1021 1021 1022 1023 1023 1024 1024 1024 1026 1027 1029 1030 1032 1032 1032 1032 1033 1034 1034 1036 1036

Contents

55 Pump Unit Operation Pump Theory Pump Design Tab Connections Page Parameters Page Curves Page Links Page User Variables Page Notes Page Pump Rating Tab Curves Page Curve Property View Curves Profiles Property View Generate Curve Options Property View NPSH Page Nozzles Page Inertia Page Electric Motor Page Design Page Pump Performance Tab Results Page Power Page Pump Dynamics Tab Specs Page Holdup Page Stripchart Page References 56 Separation Operations

1037 1037 1038 1039 1039 1039 1041 1042 1042 1042 1043 1045 1046 1047 1048 1050 1051 1051 1054 1054 1055 1055 1055 1055 1058 1058 1058 1059

References

1059

57 Component Splitter

1061

Theory Component Splitter Property View Design Tab Connections Page Parameters Page Splits Page TBP Cut Point Page User Variables Page Notes Page Rating Tab Nozzles Page Worksheet Tab Dynamics Tab Specs Page

Contents

1061 1062 1062 1062 1062 1063 1064 1065 1065 1065 1066 1066 1066 1066

xxvii

58 Separator, 3-Phase Separator, and Tank Theory Energy Balance Physical Parameters Separator Ops General Property Views Design Tab Connections Page Parameters Page User Variables Page Notes Page Reactions Tab Results Page Rating Tab Sizing Page Nozzles Page Heat Loss Page Level Taps Page Option Page C.Over Setup Page C. Over Results Page Worksheet Tab Dynamics Tab Specs Page Holdup Page Stripchart Page Heat Exchanger Page 59 Shortcut Column Shortcut Column Property View Design Tab Connections Page Parameters Page Rating Tab Worksheet Tab Performance Tab Dynamics Tab

1067 1068 1069 1069 1071 1071 1071 1071 1072 1072 1072 1072 1073 1073 1075 1076 1082 1084 1084 1090 1090 1090 1091 1093 1093 1093 1095 1095 1095 1095 1096 1096 1096 1096 1097

60 Solid Separation Operations

1099

61 Baghouse Filter

1101

Design Tab Connections Page Parameters Page Notes Page Rating Tab Sizing Page Worksheet Tab Performance Tab

xxviii

1101 1101 1101 1102 1102 1102 1102 1102

Contents

Results Page Dynamics Tab 62 Cyclone Design Tab Connections Page Parameters Page Solids Page User Variables Page Rating Tab Sizing Page Constraints Page Worksheet Tab Performance Tab Results Page Dynamics Tab 63 Hydrocyclone Design Tab Connections Page Parameters Page Solids Page User Variables Page Notes Page Rating Tab Sizing Page Constraints Page Worksheet Tab Performance Tab Results Page Dynamics Tab 64 Rotary Vacuum Filter Design Tab Connections Page Parameters Page User Variables Page Notes Page Rating Tab Sizing Page Cake Page Worksheet Tab Dynamics Tab 65 Simple Solid Separator Design Tab Connections Page Parameters Page

Contents

1103 1103 1105 1105 1105 1105 1106 1107 1107 1107 1108 1108 1108 1108 1109 1111 1111 1111 1111 1112 1112 1112 1112 1112 1113 1113 1113 1114 1114 1115 1115 1115 1115 1116 1116 1116 1116 1116 1117 1117 1119 1119 1119 1119

xxix

Splits Page User Variables Page Notes Page Rating Tab Worksheet Tab Dynamics Tab 66 Material Streams The "Spec Stream As..." Property View Worksheet Tab Conditions Page Properties Page Composition Page Input Composition Property View Oil & Gas Feed Page Petroleum Assay Page K Value Page User Variables Page Notes Page Cost Parameters Page Normalized Yields Page Acid Gas Page PSD Properties Page Sulfur Recovery Page Attachments Tab Unit Ops Page Analysis Page Dynamics Tab Specs Page Stripchart Page 67 Energy Streams Stream Tab Unit Ops Tab Dynamics Tab Stripchart Tab User Variables Tab 68 Subflowsheet Operations Introduction Subflowsheet Property View Adding a Subflowsheet Connections Tab Parameters Tab Transfer Basis Tab Variables Tab Notes Tab Lock Tab

xxx

1119 1120 1120 1120 1120 1120 1121 1122 1122 1123 1125 1130 1131 1132 1134 1136 1137 1137 1137 1137 1138 1138 1139 1139 1140 1140 1141 1141 1142 1143 1143 1144 1144 1144 1144 1145 1145 1146 1146 1147 1148 1148 1151 1151 1151

Contents

Index

Contents

1153

xxxi

xxxii

Contents

1 Unit Operations Overview

About this Guide The Aspen HYSYS Unit Operations Guide provides detailed information regarding: l

Common Property Views

l

Input Experts

l

Column Operations

l

Columns

l

Column Analysis

l

Electrolyte Operations

l

Heat Transfer Operations

l

Logical Operations

l

Piping Operations

l

Reactor Operations

l

Rotating Equipment

l

Separation Operations

l

Solid Separation Operations

l

Streams

l

Subflowsheet Operations

For information related to other aspects of HYSYS: l

l

l

For information regarding HYSYS Petroleum Refining operations, please refer to the Aspen HYSYS Petroleum Refining Unit Operations & Reactor Models Reference Guide or the HYSYS Help. For information on using Assay Management in HYSYS, please refer to the Assay Management in Aspen HYSYS Petroleum Refining Reference Guide or the HYSYS Help. For information regarding the Properties Environment, HYSYS Upstream operations, Sulsim (Sulfur Recovery) operations, Acid Gas Cleaning, Simulation and Analysis Tools, Safety Analysis, BLOWDOWN Technology,


1

HYSYS Dynamics, and HYSYS Equation Oriented (EO) Solving, please refer to the HYSYS Help.

Integrated Steady State and Dynamics Simulation HYSYS uses an integrated steady state and dynamic modeling capability in which the same model can be evaluated from either perspective with full sharing of process information. The components that comprise HYSYS provide a powerful approach to steady state process modeling. The comprehensive selection of operations and property methods lets you model a wide range of processes with confidence. Perhaps even more important is how the HYSYS approach to modeling maximizes your return on simulation time through increased process understanding. The key to this is the Event Driven operation. By using a ‘degrees of freedom’ approach, calculations in HYSYS are performed automatically. HYSYS performs calculations as soon as unit operations and property packages have enough required information. Any results, including passing partial information when a complete calculation cannot be performed, is propagated bi-directionally throughout the flowsheet. What this means is that you can start your simulation in any location using the available information to its greatest advantage. Since results are available immediately - as calculations are performed - you gain the greatest understanding of each individual aspect of your process.

Multi-Flowsheet Architecture The multi-flowsheet architecture of HYSYS is vital to this overall modeling approach. Although HYSYS is designed to allow the use of multiple property packages and the creation of pre-built templates, the greatest advantage of using multiple flowsheets is that they provide an extremely effective way to organize large processes. By breaking flowsheets into smaller components, you can easily isolate any aspect for detailed analysis. Each of these sub-processes is part of the overall simulation, automatically calculating like any other operation. The design of the HYSYS interface is consistent, if not integral, with this approach to modeling. Access to information is the most important aspect of successful modeling, with accuracy and capabilities accepted as fundamental requirements. Not only can you access whatever information you need when you need it, but the same information can be displayed simultaneously in a variety of locations. Just as there is no standardized way to build a model, there is no unique way to look at results. HYSYS uses a variety of methods to display

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process information - individual property views, the PFD, Workbook, graphical Performance Profiles, and Tabular Summaries. Not only are all of these display types simultaneously available, but through the object-oriented design, every piece of displayed information is automatically updated whenever conditions change.

Extensibility and Customization The inherent flexibility of HYSYS allows for the use of third party design options and custom-built unit operations. These can be linked to HYSYS through OLE Extensibility. This section covers the various unit operations, template and column subflowsheet models, optimization, and dynamics. Since HYSYS is an integrated steady state and dynamic modeling package, the steady state and dynamic modeling capabilities of each unit operation are described successively, illustrating how the information is shared between the two approaches. In addition to the physical operations there is a chapter for logical operations, which do not physically perform heat and material balance calculations, but that impart logical relationships between the elements that make up your process.

Model Categories The following is a brief definition of categories used in this volume: Term

Definition

Physical Operations

Governed by thermodynamics and mass/energy balances, as well as operation-specific relations.

Logical Operations

The Logical Operations presented in this volume are primarily used in Steady State mode to establish numerical relationships between variables. Examples include the Adjust and Recycle. There are, however, several operations such as the Spreadsheet and Set operation which can be used in Steady State and Dynamic mode.

Subflowsheets

You can define processes in a subflowsheet, which can then be inserted as a “unit operation” into any other flowsheet. You have full access to the operations normally available in the main flowsheet.

Columns

Unlike the other unit operations, the HYSYS Column is contained within a separate subflowsheet, which appears as a single operation in the main flowsheet.

Integrated into the steady state modeling is multi-variable optimization. Once you have reached a converged solution, you can construct virtually any objective function with the Optimizer. There are five available solution algorithms for both unconstrained and constrained optimization problems, with an automatic


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backup mechanism when the flowsheet moves into a region of non-convergence. HYSYS offers an assortment of analysis tools which can be attached to process streams and unit operations. These tools interact with the process model and provide additional information. In this guide, each operation is explained in its respective chapters for steady state and dynamic modeling. A separate guide has been devoted to the principles behind dynamic modeling. HYSYS is the first simulation package to offer dynamic flowsheet modeling backed up by rigorous property package calculations. Note: The HYSYS Dynamics license is required to use the features in the HYSYS dynamics mode.

HYSYS has a number of unit operations, which can be used to assemble flowsheets. By connecting the proper unit operations and streams, you can model a wide variety of oil, gas, petrochemical, and chemical processes. Included in the available operations are those which are governed by thermodynamics and mass/energy balances, such as Heat Exchangers, Separators, and Compressors, and the logical operations like the Adjust, Set, and Recycle. A number of operations are also included specifically for dynamic modeling, such as the Controller, Transfer Function Block, and Selector. The Spreadsheet is a powerful tool, which provides a link to nearly any flowsheet variable, allowing you to model “special” effects not otherwise available in HYSYS.

Degrees of Freedom In modeling operations, HYSYS uses a Degrees of Freedom approach, which increases the flexibility with which solutions are obtained. For most operations, you are not constrained to provide information in a specific order, or even to provide a specific set of information. As you provide information to the operation, HYSYS calculates any unknowns that can be determined based on what you have entered. For example, consider the Pump operation. If you provide a fully-defined inlet stream to the pump, HYSYS immediately passes the composition and flow to the outlet. If you then provide a percent efficiency and pressure rise, the outlet and energy streams is fully defined. If, on the other hand, the flowrate of the inlet stream is undefined, HYSYS cannot calculate any outlet conditions until you provide three parameters, such as the efficiency, pressure rise, and work. In the case of the Pump operation, there are three degrees of freedom, thus, three parameters are required to fully define the outlet stream.

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All information concerning a unit operation can be found on the tabs and pages of its property view. Each tab in the property view contains pages which pertain to the unit operation, such as its stream connections, physical parameters (for example, pressure drop and energy input), or dynamic parameters such as vessel rating and valve information.

Adding Unit Operations You can use the Model Palette to add HYSYS unit operations, streams, and subflowsheets to the main flowsheet or a sub-flowsheet. Operations can also be installed and set up from the Workbook, which is a spreadsheet style view of the simulation environment. Note: The standard Model Palette is available for the main flowsheet and the Standard Sub-Flowsheet. However, Column Sub-Flowsheets, EO Sub-Flowsheets, Aspen Hydraulics Sub-Flowsheets, and Sulfur Recovery Unit (SRU) Sub-Flowsheets feature different model palettes. These palettes feature different unit operations depending on the sub-flowsheet type.

To access the Model Palette: l

Press F4.

l

Press F12. -or-

l

From the View ribbon tab | Show group, click the Model Palette

button. To add a stream: l

On the Model Palette, in the upper-right corner, click the desired stream type. Name

Icon

Material Stream Energy Stream

The upper-right corner of the model palette also allows you to add a Standard Sub-Flowsheet or an EO Sub-Flowsheet.


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Name

Icon

Standard Sub-Flowsheet

EO Sub-Flowsheet

To add other unit operations or sub-flowsheets: 1. On the Model Palette, select one of the following Views: o

Text View : Display the icon, name, and description for each unit operation.

o

Grid View : Displays only the icon for each unit operation. You can hover over a unit operation to view the associated tooltip.

2. You can either: o

Type a search term in the search bar, and then click . Searches are filtered based on the name and description. -or-

o

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Select one of the categories on the left-hand side. Category

Associated Unit Operations/Sub-Flowsheets

All

Shows all available unit operations and sub-flowsheets.


Category Dynamics & Control

External Model


Associated Unit Operations/Sub-Flowsheets o

Split-Range Controller

o

Ratio Controller

o

PID Controller

o

MPC Controller

o

DMCPlus Controller

o

Selector

o

Digital Control Point

o

Transfer Function Block

o

Boolean Not Gate

o

Boolean And Gate

o

Boolean Or Gate

o

Boolean XOr Gate

o

Boolean Off Delay Gate

o

Boolean On Delay Gate

o

Boolean Latch Gate

o

Boolean Count Up Gate

o

Boolean Count Down Gate

o

Cause-and-Effect Matrix

o

CAPE-OPEN 1.0 Unit

o

CAPE-OPEN 1.1 Unit

o

Equilibrium Unit

o

External Data Linker

o

ACM Operation

o

User Unit Op

o

Mach Number Unit

o

Virtual Stream

o

Wellhead PQ Unit Operation

o

SULSIM Extension

7

Category Heat Transfer

Manipulator

Piping & Hydraulics

8


Heater

o

Cooler

o

Heat Exchanger

o

Fired Heater

o

Air Cooler

o

LNG Exchanger

o

Plate Exchanger

o

Adjust

o

Spreadsheet

o

Recycle

o

Set

o

Stream Saturator

o

Balance

o

Stream Cutter

o

Petroleum Feeder

o

Assay Manipulator

o

Product Blender

o

Black Oil Translator

o

Lumper

o

Delumper

o

Mixer

o

Tee

o

Pipe Segment

o

Gas Pipe

o

Aspen Hydraulics Sub-Flowsheet

o

OLGA Link

o

Petroleum Experts GAP

o

PIPESIM

o

PipeSim Link Unit

o

PipeSim Net Unit


Category Pressure Changer

Reactor



Pump

o

Control Valve

o

Relief Valve

o

Compressor

o

Expander

o

Continuously Stirred Tank

o

Plug Flow Reactor

o

Conversion Reactor

o

Equilibrium Reactor

o

Gibbs Reactor

o

Yield Shift Reactor

o

Neutralizer

o

HF Alkylation

o

H2SO4 Alkylation

o

Isomerization

o

Naphtha Hydrotreater

o

Catalytic Reformer

o

Hydrocracker

o

Hydroprocessing Bed

o

Fluidized Catalytic Cracking (FCC)

o

CatGas Hydrotreater SHU

o

CatGas Hydrotreater HDS

o

Delayed Coker

o

Visbreaker

o

Sulfur Recovery Unit (SRU) Sub-Flowsheet

o

Petroleum Shift Reactor

o

HYPlan Model

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Category Separator


Separator

o

3 Phase Separator

o

Tank

o

Distillation Column

o

Blank Column

o

Component Splitter

o

Absorber

o

Refluxed Absorber

o

Reboiled Absorber

o

Three Phase Distillation

o

Shortcut Column

o

Refining Short-Cut Column

o

Liquid-Liquid Extractor

o

3 Stripper Crude

o

4 Stripper Crude

o

Vacuum Resid Tower

o

FCCU Main Frac

o

Simple Solid Separator

o

Cyclone

o

Hydrocyclone

o

Liquid-liquid Hydrocyclone

o

Baghouse Filter

o

Rotary Vacuum Filter

o

Precipitator

o

Crystallizer

Note: The electrolyte operations are only available if your case is an electrolyte system; the selected fluid package must support electrolytes.

3. Select the desired unit operation or sub-flowsheet. To add it to the PFD: o

Drag and drop the icon onto the PFD. -or-

o

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Double-click the icon.


Basic Unit Operation Property View Although each unit operation differs in functionality and operation, in general, the unit operation property view remains consistent in its overall appearance. Most operation property views contain the following common objects: l

l

l

Delete button. This button lets you delete the unit operation from the current simulation case. Only the unit operation is deleted, any streams attached to the unit operation is left in the simulation case. Status bar. This bar displays messages associated to the calculation status of the unit operation. The messages also indicate the missing or incorrect data in the operation. Ignore check box. This check box lets you toggle between including and excluding the unit operation in the simulation process calculation. o

To ignore the operation during calculations, select the check box. HYSYS completely disregards the operation until you restore the operation to an active state by clearing the check box. Note: You can also right-click and select the Ignore/Restore Unit Operation command to ignore or restore multiple selected flowsheet operations.

The Operation property view also contain several different tabs which are operation specific, however the Design, Rating, Worksheet, and Dynamics tabs can usually be found in each unit operation property view and have similar functionality. Tab

Description

Design

Connects the feed and outlet streams to the unit operation. Other parameters such as pressure drop, heat flow, and solving method are also specified on the various pages of this tab.

Rating

Rates and Sizes the unit operation vessel. Specification of the tab is not always necessary in Steady State mode, however it can be used to calculate vessel hold up.

Worksheet

Displays the Conditions, Properties, Composition, and Pressure Flow values of the streams entering and exiting the unit operation.

Dynamics

Sets the dynamic parameters associated with the unit operation such as valve sizing and pressure flow relations. Not relevant to steady state modelling. For information on dynamic modeling implications of this tab, refer to the HYSYS Dynamics section.

Note: If negative pressure drop occurs in a vessel, the operation will not solve and a warning message appears in the status bar.


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Object Inspect Menu To access the Object Inspect menu of a unit operation property view, right-click on any empty area of the property view. The unit operation property view all have the following common commands in the Object Inspect menu: Command

Description

Print Datasheet

Lets you access the Select DataBlocks to Print property view.

Open Page

Lets you open the active page into a new property view.

Find in PFD

Lets you locate and display the object icon in the PFD property view. This command is useful if you already have access to an object's property view and want to see where the object is located in the PFD. This command is only available in the Object Inspect menu of the HYSYS stream & operation property views.

Connections

Lets you access the Logical Connections For... Property View.

Logical Connections For... Property View The Logical Connections for... property view lets you determine simulation dependencies between objects which are not otherwise shown via connecting lines on the PFD. Certain HYSYS operations can write to any other object and if the user is looking at the object being written to, they have no way of telling this, other than that the value might be changing. For example, one can determine if one spreadsheet is writing to another. Note: The Logical Connections for... property view is different if accessed from a Spreadsheet property view since there is an additional column (This Name) in the table. The This Name column displays the spreadsheet cell that contains the information/variable connected to the spreadsheet.

The table in the Logical Connections for... property view contains the following columns: l

Remote Name column displays the name of the operation or stream being written to or read from the active object. o

l

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Double-click on a particular entry of the Remote Name column to open the property view of the operation or stream.

Remote Type column displays the operation type (pump, valve, stream, and so forth) of the remote object from the current/active property view.


The Show All check box lets you toggle between displaying or hiding all the other operations and streams that the selected object knows about. Duplicate connectivity information may be shown otherwise (either via a line on the PFD or elsewhere in a Logical operations property view, for example). Usually, you do not need to select this check box. Note: There is only one Show All check box for your HYSYS session. When the check box is changed, the current setting is effective for all Logical Connections For... property view.

To access the Logical Connections for… view of a HYSYS PFD object: 1. Open the object's property view. 2. Right-click in an empty area of the object's property view. The Object Inspect menu associated to the object appears. 3. Select Connections command from the Object Inspect menu. Note: The information displayed in the Logical Connections for... property view is primarily use for the Spreadsheet, Cause and Effect Matrix operation, Event Scheduler operation, and any other operations that read/write from/to these property views.


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2 Unit Operation Common Property Views

Each unit operation in HYSYS contains some common information and options grouped into common property views, tabs, and pages. The following sections describe the common objects in HYSYS operation property view.

Graph Control Property View The Graph Control property view and its options are available for all plots in HYSYS. The options are grouped into five tabs: l

l

l

l

l

Data - Modify the variable characteristics (type, name, color, symbol, line style, and line thickness) of the plot. Axes - Modify the axes characteristics (label name, display format, and axes value range) of the plot. Title - Modify the title characteristics (label, font style, font color, borders, and background color) of the plot. Legend - Modify the legend characteristics (border, background color, font style, font color, and alignment) of the plot. Plot Area - Modify the plot characteristics (background color, grid color, frame color, and cross hair color) of the plot.

To access the Graph Control property view, do one of the following: l

l

Right-click any spot on an active plot and select the Graph Control command from the Object Inspect menu. Click in the plot area to make the plot the active object. Then, either double-click on the plot Title or Legend to access the respective tab of the Graph Control property view.


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Heat Exchanger Page The Heat Exchanger page on the Dynamics tab for most vessel unit operations in HYSYS contains the options use to configure heat transfer method within the unit operation. There are three options to choose from: l

l

l

None radio button option indicates that there is no energy stream or heat exchanger in the vessel. The Heat Exchanger page is blank and you do not have to specify an energy stream for the unit operation to solve. Duty radio button option indicates that there is an energy stream in the vessel. The Heat Exchanger page contains the HYSYS standard heater or cooler parameters and you have to specify an energy stream for the unit operation to solve. Tube Bundle radio button option indicates that there is heat exchanger in the vessel and lets you simulate a kettle reboiler or chiller. The Heat Exchanger page contains the parameters used to configure a heat exchanger and you have to specify material streams of the heat exchanger for the unit operation to solve.

Note: The Tube Bundle option is only available in Dynamics mode. Note: The Tube Bundle option is only available for the following unit operations: Separator, Three Phase Separator, Condenser, and Reboiler.

Duty Radio Button Options When you select the Duty radio button the following options are available.

Heater Type Group In the Heater Type group, there are two heating methods available to the general vessel operation: l

Vessel Heater

l

Liquid Heater

If you select the Vessel Heater radio button, 100% of the duty specified or calculated in the SP field is applied to the vessel’s holdup. (1) where: Q = total heat applied to the holdup QTotal = duty calculated from the duty source

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If you select the Liquid Heater radio button, the duty applied to the vessel depends on the liquid level in the tank. You must specify the heater height in the Top of Heater and Bottom of Heater cells that appear with Heater Height as % Vessel Volume group. The heater height is expressed as a percentage of the liquid level in the vessel operation. The default values are 5% for the Top of the Heater and 0% for the Bottom of the Heater. These values are used to scale the amount of duty that is applied to the vessel contents. (2)

where: L = liquid percent level (%) T = top of heater (%) B = bottom of heater (%) The Percent Heat Applied can be calculated as follows: (3) It is shown that the percent of heat applied to the vessel’s holdup directly varies with the surface area of liquid contacting the heater.

Duty Source/Source Group In the Duty Source/Source group, you can choose whether HYSYS calculates the duty applied to the vessel from a direct energy source or from a utility source. l

If you select the Direct Q radio button, the Direct Q group appears, and you can directly specify the duty applied to the holdup in the SP field.


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The following table describes the purpose of each object in the Direct Q group.

l

Object

Description

SP

The heat flow value in this cell is the same value specified in the Duty field of the Parameters page on the Design tab. Any changes made in this cell are reflected on the Duty field of the Parameters page on the Design tab.

Min. Available

Lets you specify the minimum amount of heat flow.

Max. Available

Lets you specify the maximum amount of heat flow.

If you select the Utility radio button, the Utility Properties group appears, and you can specify the flow of the utility fluid. o

The duty is then calculated using the local overall heat transfer coefficient, the inlet fluid conditions, and the process conditions. The calculated duty is then displayed in the SP field or the Heat Flow field.

o

If you select the Heating radio button, the duty shown in the SP field or Heat Flow field is added to the holdup. If you select the Cooling radio button, the duty shown in the SP field or Heat Flow field is subtracted from the holdup.

o

For more information regarding how the utility option calculates duty, refer to the Logical Operations.

Tube Bundle Radio Button When you select the Tube Bundle radio button, the Tube Bundle options are available. Note: The Tube Bundle option is only available in Dynamics mode. Note: If you had an energy stream attached to the unit operation, HYSYS automatically disconnects the energy stream when you switch to the Tube Bundle option.

The Tube Bundle option lets you configure a shell tube heat exchanger (for example, kettle reboiler or kettle chiller). l

l

18

In the kettle reboiler, the process fluid is typically on the shell side and the process fluid is fed into a liquid "pool" which is heated by a number of tubes. A weir limits the amount of liquid in the pool. The liquid overflow is placed under level control and provides the main liquid product. The vapor is circulated back to the vessel. In the kettle chiller, the process fluid is typically on the tube side with a refrigerant on the shell side. The refrigerant if typically pure and cools by evaporation. The setup is similar to the reboiler except that there is no weir or level control.


The unit operation icon in the PFD also changes to indicate that a heat exchanger has been attached to the unit operation.

The following table lists and describes the options available to configure the heat exchanger: Object

Description

Parameters group Tube Volume cell

Lets you specify the volume of the tubes in the heat exchanger.

Vessel Liquid U cell

Lets you specify the heat transfer rate of the liquid in the shell.

Vessel Vapor U cell

Lets you specify the heat transfer rate of the vapor in the shell.

Tube Liquid U cell

Lets you specify the heat transfer rate of the liquid in the tube.

Tube Vapor U cell

Lets you specify the heat transfer rate of the vapor in the tube.

Heat Transfer Area cell

Lets you specify the total heat transfer area between the fluid in the shell and the fluid in the tube.

Bundle Top Height cell

Lets you specify the location of the top tube/bundle based on the height from the bottom of the shell.

Bundle Bottom Height cell

Lets you specify the location of the bottom tube/bundle based on the height from the bottom of the shell.

Specs group Tube Dp cell

Lets you specify the pressure drop within the tubes. You have to select the associate check box in order to specify the pressure drop.

Tube K cell

Lets you specify the pressure flow relationship value within the tubes. You have to select the associate check box in order to specify the pressure flow relationship value.


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Object

Description

Tube UA Reference Flow cell

Lets you set a reference point that uses HYSYS to calculate a more realistic UA value. If no reference point is set then UA is fixed. UA is the product of overall heat transfer multiply with overall heat transfer area, and depends on the flow rate. If a value is specified for the Reference Flow, the heat transfer coefficient is proportional to the (mass flow ratio)0.8. The equation below is used to determine the actual UA:

Reference flows generally help to stabilize the system when you do shut downs and startups as well. Minimum Flow Scale Factor cell

The ratio of mass flow at time t to reference mass flow is also known as flow scaled factor. The minimum flow scaled factor is the lowest value which the ratio is anticipated at low flow regions. This value can be expressed in a positive value or negative value. l

A positive value ensures that some heat transfer still takes place at very low flows.

l

A negative value ignores heat transfer at very low flows.

A negative minimum flow scale factor is often used in shut downs if you are not interested in the results or run into problems shutting down the heat exchanger. If the Minimum Flow Scale Factor is specified, the actual UA is calculated using the ratio if the ratio is greater

than the Min Flow Scale Factor. Otherwise the Min Flow Scale Factor is used. Calculate K button

Lets you calculate the K value based on the heat exchanger specifications.

Shell Dp cell

Lets you specify the pressure drop within the shell.

Summary group

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Actual UA cell

Displays the calculated UA in Dynamics mode.

Shell Liq. Percent Level cell

Displays the calculated liquid level in the shell at percentage value.

Tube Liq. Volume Percent cell

Lets you specify in percentage value the volume of liquid in the tube.

Shell Duty cell

Displays the calculated duty value in the shell.


Object

Description

Use Tube Trivial Level and Fraction Calc. radio button

Lets you select the volume percent level variable for the vessel fraction calculation.

Use Tube Normal Level and Fraction Calc. radio button

Lets you select the liquid percent level variable for the vessel fraction calculation.

View Tube HoldUp button

Lets you access the tube HoldUp Property View.

This option uses a variable that is independent of the vessel shape or orientation.

This option uses a variable that is dependent of the vessel shape and orientation.

Holdup Page Each unit operation in HYSYS has the capacity to store material and energy. The Holdup page contains information regarding the properties, composition, and amount of the holdup. Most Holdup pages contains the following common objects/options: Objects

Description

Phase column

Displays the phase of the fluid available in the unit operation’s holdup volume. Each available phase occupies a volume space within the unit operation.

Accumulation column

Displays the rate of change of material in the holdup for each phase.

Moles column

Displays the amount of material in the holdup for each phase.

Volume column

Displays the holdup volume of each phase.

Total row

Displays the sum of the holdup accumulation rate, mole value, and volume value.

Advanced but- Lets you access the unit operation’s HoldUp Property View that ton provides more detailed information about the holdup of that unit operation.


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Holdup Property View The Holdup property view displays the detailed calculated results of the holdup data in the following tabs: l

l

l

l

l

General tab. Displays the phase, accumulation, moles, volume, duty and holdup pressure of the heat exchanger. o

Select the Active Phase Flip Check check box to enable HYSYS to check if there is a phase flip between Liquid 1 (light liquid) and Liquid 2 (heavy liquid) during simulation and generate a warning message whenever the phase flip occur. If the check box is clear, HYSYS generates a warning only on the first time the phase flip occur.

o

Refer to Advanced Holdup Properties in the HYSYS Dynamic Modeling section for more information.

Nozzles tab. Lets you modify nozzle configuration attached to the heat exchanger. Efficiencies tab. Lets you modify the efficiency of the recycle, feed nozzle, and product nozzle of the heat exchanger. Properties tab. Displays the temperature, pressure, enthalpy, density, and molecular weight of the holdup in the heat exchanger. Compositions tab. Displays the composition of the holdup in the heat exchanger.

For detailed technical information on the Holdup Model is, refer to Holdup Model.

Nozzles Page The Nozzles page (from the Rating Tab) in most of the operations property view lets you specify the elevation and diameter of the nozzles connected to the operation. Note: The Nozzles page is only available if the HYSYS Dynamics license is activated.

Depending on the type of operation, the options in the Nozzles page varies. The following table lists and describes the common options available in the page:

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Object

Description

Base Elevation Relative to Ground Level field

Lets you specify the height/elevation between the bottom of the operation and the ground.

Diameter row

Lets you specify the diameter of the nozzle for each material stream flowing into and out of the operation.


Object

Description

Elevation (Base) row

Lets you specify the height/elevation between the nozzle and the base of the operation.

Elevation (Ground) row

Lets you specify the height/elevation between the nozzle and the ground.

Notes Pages or Tabs Use the Notes tab or any Notes page to enter or revise notes. Notes can be useful for informing other people working with your case about changes and assumptions you have made. You can: l l

l

Enter notes in the Notes window. Make use of all common formatting options, bold, italic, indents, fonts, etc. Use the Notes Manager to search across multiple notes locations.

To enter notes: 1. Click anywhere in the Notes window to make it active. 2. Type in any relevant notes you have regarding such things as fluid packages, assays, user properties, operations, and so on.

Notes Manager The Notes Manager lets you survey and edit notes associated all objects on the Flowsheet from a central location. 1. From the View ribbon tab > Show group, select Notes Manager. 2. In the list of available objects select the object that contains the note you want to view. Click the Plus icon to expand the tree browser revealing more selections. 3. If a valid note is present in the object the note appears in the Note group. From here you can view and modify the note. Tip: You can also access the Notes Manager by pressing the CTRL G hot key. l

Select the View Objects with Notes Only check box to display only objects that contain a valid note.

l

Click Clear to delete the entire note from the selected object.

l

Click View to open the property view of the selected object.

l

l

Select the Search notes containing the string check box and enter a string in the corresponding field to filter the list of available objects to objects that contain the specified string. Select the Search notes modified since check box and enter month,


23

day and year to filter the list of available objects to objects whose notes modified since the specified date.

Holdup Model Dynamic behavior arises from the fact that many pieces of plant equipment have some sort of material inventory or holdup. A holdup model is necessary because changes in the composition, temperature, pressure or flow in an inlet stream to a vessel with volume (holdup) are not immediately seen in the exit stream. The model predicts how the holdup and exit streams of a piece of equipment respond to input changes to the holdup over time. In some cases, the holdup model corresponds directly with a single piece of equipment in Aspen HYSYS. For example, a separator is considered a single holdup. In other cases, there are numerous holdups within a single piece of equipment. In the case of a distillation column, each tray can be considered a single holdup. Heat exchangers can also be split up into zones with each zone being a set of holdups. Calculations included in the holdup model are: l

Material and energy accumulation

l

Thermodynamic equilibrium

l

Heat transfer

l

Chemical reaction

The new holdup model offers certain advantages over the previous HYSYS dynamic model: l

l

l

An adiabatic PH flash calculation replaces the bubble point algorithm used in the previous holdup model. Adiabatic flashes also allow for more accurate calculations of vapor composition and pressure effects in the vapor holdup. Flash efficiencies can be specified allowing for the modeling of non-equilibrium behavior between the feed phases of the holdup. The placement of feed and product nozzles on the equipment has physical meaning in relation to the holdup. For example, if the vapor product nozzle is placed below the liquid level in a separator, only liquid exits from the nozzle.

Assumptions of Holdup Model There are several underlying assumptions that are considered in the calculations of the holdup model:

24

l

Each phase is assumed to be well mixed.

l

Mass and heat transfer occur between feeds to the holdup and material


already in the holdup. l

Mass and heat transfer occur between phases in the holdup.

Accumulation The lagged response that is observed in any unit operation is the result of the accumulation of material, energy, or composition in the holdup. To predict how the holdup conditions change over time, a recycle stream is added alongside the feed streams. For example, the material accumulation in a holdup can be calculated from: (1)

The recycle stream is not a physical stream in the unit operation. Rather, it is used to introduce a lagged response in the output. Essentially, the recycle stream represents the material already existing in the piece of equipment. It becomes apparent that a greater amount of material in the holdup means a larger recycle stream and thus, a greater lagged response in the output.

The holdup model is used to calculate material, energy, and composition accumulation. Material accumulation is defaulted to calculate at every integration time step. The energy of the holdup is defaulted to calculate at every second time step. The composition of the holdup is defaulted to calculate at every tenth time step.

Non-Equilibrium Flash As material enters a holdup, the liquid and vapor feeds can associate in different proportions with the existing material already in the holdup. For instance, a separator’s vapor and liquid feeds can enter the column differently. It is very likely that the liquid feed mixes well with the liquid already in the holdup. The vapor feed is not mixed as well with the existing material in the vessel since the residence time of the vapor holdup is much smaller than that of the liquid. If the feed nozzle is situated close to the vapor product nozzle, it is possible that even less mixing occurs. In the physical world, the extent of mixing the feeds with a holdup depends on the placement of the feed nozzles, the amount of holdup, and the geometry of the piece of equipment.


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Efficiencies In HYSYS, you can indirectly specify the amount of mixing that occurs between the feed phases and the existing holdup using feed, recycle, and product efficiencies. These feed efficiency parameters can be specified on the Efficiencies tab of the unit operation’s Advance property view. Click the Advance button on the Holdup page under the Dynamics tab to open the Advance property view. Essentially, the efficiencies determine how rapidly the system reached equilibrium. If all efficiencies are 1, then all feeds reach equilibrium instantaneously. If the values are lower, it takes longer and the phases cannot be in equilibrium and can have different temperatures. A flash efficiency can be specified for each phase of any stream entering the holdup. A conceptual diagram of the non-equilibrium flash is shown for a two phase system in the figure below:

As shown, the flash efficiency, η, is the fraction of feed stream that participates in the rigorous flash. If the efficiency is specified as 1, the entire stream participates in the flash; if the efficiency is 0, the entire stream bypasses the flash and is mixed with the product stream. The recycle stream (and any streams entering the holdup) participates in the flash. You can specify the flash efficiency for each phase of the recycle stream and any feed entering the holdup. The flash efficiency can also be specified for each phase of any product streams leaving the holdup. Note: Product flash efficiencies are only used by the holdup model when reverse flow occurs in the product flow nozzles. In such cases, the product nozzle effectively becomes a feed nozzle and uses the product flash efficiencies that you provided.

The default efficiencies for the feed, product, and recycle streams is 1, and this value is sufficient in the vast majority of cases. The flash efficiencies can be changed to model non-equilibrium conditions. For example, the efficiency of vapor flowing through a vessel containing liquid can be reduced if the residence time of the vapor is very small and there is little time for it to reach thermodynamic equilibrium with the liquid. Also, in some narrow boiling systems,

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lower efficiencies can be used to reduce the rate at which material can condense or evaporate. This can help to stabilize the pressure in certain difficult cases such as narrow boiling systems like steam. For example, a water system is heated by pure steam (no inerts) can encounter problems if the stream efficiency is specified as 1. If the holdup material is significantly larger than the stream flow, all the steam condenses and the holdup temperature increases accordingly. No vapor is present which can complicate pressure control of the system. In the physical world, typically not all of the steam condenses in the water and there are also some inerts (e.g., nitrogen or air) present in the system. Using lower efficiencies can help to model this system better.

Nozzles In HYSYS, you can specify the feed and product nozzle locations and diameters. These nozzle placement parameters can be specified in the unit operation’s Nozzles page under the Rating tab.

The placement of feed and product nozzles on the equipment has physical meaning in relation to the holdup. The exit stream’s composition depends partially on the exit stream nozzle’s location in relation to the physical holdup level in the vessel. If the product nozzle is located below the liquid level in the vessel, the exit stream draws material from the liquid holdup. If the product nozzle is located above the liquid level, the exit stream draws material from the vapor holdup. If the liquid level sits across a nozzle, the mole fraction of liquid in the product stream varies linearly with how far up the nozzle the liquid is.

Static Head Contributions When the Static Head Contributions check box is selected on the Options tab of the Integrator property view, Aspen HYSYS calculates static head using the following contributions: l

Levels inside separators, Towers, and so forth

l

Elevation differences between connected equipment

Note: Including static head contributions in the modeling of pressure-flow dynamics is an option in Aspen HYSYS.


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For unit operations with negligible holdup, such as the valve operation, Aspen HYSYS incorporates only the concept of nozzles. There is no static head contributions for levels, unless the feed and product nozzles are specified at different elevations. You can specify the elevation of both the feed and product nozzles. If there is a difference in elevation between the feed and product nozzles, Aspen HYSYS uses this value to calculate the static head contributions. It is recommended that static head contributions not be modeled in these unit operations in this way since this is not a realistic situation. Static head can be better modeled in these unit operations by relocating the entire piece of equipment. Static head is important in vessels with levels. For example, consider a vertical separator unit operation that has a current liquid level of 50%. The static head contribution of the liquid holdup makes the pressure at the liquid outlet nozzle higher than that at the vapor outlet nozzle. Nozzle location also becomes a factor. The pressure-flow relationship for the separator is different for a feed nozzle which is below the current liquid holdup level as opposed to a feed which is entering in the vapor region of the unit. It is important to notice that exit stream pressures from a unit operation are calculated at the exit nozzle locations on the piece of equipment and not the inlet nozzle locations of the next piece of equipment.

Heat Loss Model The heat loss experienced by any piece of plant equipment is taken into consideration in Aspen HYSYS. The heat loss influences the boundaries and holdups inside the equipment by contributing extra terms to the energy balance equations. There are two heat loss models available: Simple and Detailed. These models can be specified for most unit operations under the Rating tab | Heat Loss page. You can choose to neglect the heat loss calculation in the energy balance by selecting the None radio button.

Simple Model The Simple model allows you to have the heat loss calculated from specified values: Overall U value and Ambient temperature. The heat transfer area A and the fluid temperature Tf are calculated or available to HYSYS. The resulting heat loss is then: (1)

Detailed Model: Cartesian one-dimensional version Heat is lost (or gained) from the holdup fluid through the wall and insulation to the surroundings. There are several underlying assumptions that are considered during a heat loss calculation:

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l

l

l

l

l

l

There is heat capacity associated with the wall (metal) and with insulation housing the fluid There is thermal conductivity associated with the wall and with insulation housing the fluid The temperature across the wall and the temperature across the insulation are assumed to be constant (lumped parameter analysis) You can have different heat transfer coefficients on the inside of a vessel for the vapor and the liquid: the heat transfer coefficients between the holdup and the wall are not the same for the vapor and liquid The calculation assumes natural convection heat transfer on the inside and outside of the vessel The calculations do not take into account that temperatures vary along the height of the vessel depending on the phase they are in contact with at the corresponding height: this is what is meant by a one-dimensional model

In the figure above, we show the heat flow through the different material layers. A first balance can be performed across the wall: (2) and the balance across the insulation: (3) with: (4) (5) (6) (7) (8) where:


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A

heat transfer area

Δx

thickness

ρ cp

mass density heat capacity

k

thermal conductivity

h

convective heat transfer coefficient

r

thermal resistance for conductive h. transfer

q

rate of heat transfer

T

temperature

t

time

The temperature at the wall/insulation interface is calculated using a pseudo steady state assumption for viewing purposes

Detailed Model: radial one-dimensional version Since HYSYS V7.3.1, HYSYS has used a radial model for pipe segments which yields considerably different predictions from those of the Cartesian model when the insulation thickness is comparable to the wall thickness. The radial model is active by default in all newly created pipe segments in dynamics mode, in the pipe segment property view, Rating tab | Heat Model page, as shown below.

In the analysis below, the Cartesian one-dimensional version figure is still useful if representing a small angular section of a long pipe. A balance across the wall would be: (9) and the balance across the insulation: (10) with: (11) (12)

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(13) (14)

where: pipe length

L

pipe inner radius

ri

pipe outer radius

ro rins ρ

insulation outer radius mass density

cp

heat capacity

k

thermal conductivity

h

convective heat transfer coefficient

R

thermal resistance for conductive h. transfer

q

rate of heat transfer

T

temperature

t

time

Chemical Reactions Chemical reactions that occur in plant equipment are considered by the holdup model in HYSYS. Reaction sets can be specified in the Results page of the Reactions tab. The holdup model is able to calculate the chemical equilibria and reactions that occur in the holdup. In a holdup, chemical reactions are modeled by one of four mechanisms: l

Reactions handled inside thermophysical property packages

l

Extent of reaction model

l

Kinetic model

l

Equilibrium model

Related Calculations There are calculations which are not handled by the holdup model itself, but can impact the holdup calculations. The following calculations require information


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and are solved in conjunction with the holdup model as described in the following table: Calculations

Description

Vessel Level Calculations

The vessel level can be calculated from the vessel geometry, the molar holdup and the density for each liquid phase.

Vessel Pressure

The vessel pressure is a function of the vessel volume and the stream conditions of the feed, product, and the holdup. The pressure in the holdup is calculated using a volume balance equation. Holdup pressures are calculated simultaneously across the flowsheet.

Tray Hydraulics

Tray Hydraulics determines the rate from which liquid leaves the tray, and hence, the holdup and the pressure drop across the tray. The Francis Weir equation is used to determine the liquid flow based on the liquid level in the tray and the tray geometry.

Advanced Holdup Properties Each Dynamics tab | Holdup page on the unit operation property view contains an Advanced button. This button accesses the Holdup property view that provides more detailed information about the holdup of that unit operation. Right-click anywhere in the property view to bring up the object inspect menu. Selecting the Open Page command displays the information on the Holdup page in a separate property view.

General Tab This tab provides the same information as shown in the Holdup page of the Dynamics tab. The accumulation, moles, and volume of the holdup appear on this tab. The holdup pressure also appears on this tab. Select the Active Phase Flip Check check box to enable Aspen HYSYS to check if there is a phase flip between Liquid 1 (light liquid) and Liquid 2 (heavy liquid) during simulation and generate a warning message whenever the phase flip occur. If the check box is clear, Aspen HYSYS generates a warning only on the first time the phase flip occur.

Nozzles Tab Note: The Nozzles tab requires HYSYS Dynamics license.

The Nozzles tab displays the same information as shown in the Nozzles page of the Ratings tab. The nozzle diameters and elevations for each stream attached to the holdup appear on this tab. This section also displays the holdup elevation which is essentially equal to the base elevation of the piece of equipment relative to the ground. Changes to nozzle parameters can either be made in this tab or in the Nozzles page of the Ratings tab.

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Efficiencies Tab Note: The Efficiencies tab requires HYSYS Dynamics license.

The nozzle efficiencies can be specified in this tab. In Aspen HYSYS, you can indirectly specify the amount of mixing that occurs between the feed phases and existing holdup using feed, recycle and product efficiencies. A flash efficiency, η, is the fraction of feed stream that participates in the rigorous flash. If the efficiency is specified as 100, the entire stream participates in the flash; if the efficiency is 0, the entire stream bypasses the flash and is mixed with the product stream. Nozzle Efficiency

Description

Feed Nozzle Efficiency

The efficiencies of each phase for each feed stream into the holdup can be specified in these cells. These efficiencies are not used by the holdup model if there is flow reversal in the feed streams.

Product Nozzle Efficiency

Product nozzle efficiencies are used only when there is flow reversal in the product streams. In this situation, the product nozzles act as effective feed nozzles.

Recycle Efficiency

Essentially, the recycle stream represents the material already existing in the holdup. Recycle efficiencies represent how much of the material in the holdup participates in the flash.

Properties Tab The following fluid properties for each phase in the holdup appear on the Properties tab: l

Temperature

l

Pressure

l

Flow

l

Molar Fraction of the specific phase in the holdup

l

Enthalpy

l

Density

l

Molecular Weight

Compositions Tab The compositional molar fractions of each phase in the holdup appears on the Compositions tab.


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Stripchart Page Strip charts let you monitor the behavior of process variables in a graphical format during dynamics calculations. Current and historical values for each strip chart are also tabulated for further examination. You can create strip charts directly from a unit operation property view, or in the Strip Charts folder on the navigation pane. You can have multiple strip charts, each having an unlimited number of variables charted. The same variable can be used in more than one Strip Chart. Tips: l

To delete a variable from a strip chart, select the variable you want delete from the list of available variables and press DELETE. To replace the variable deleted, reselect the variable set from the Variable Set drop-down list.

l

Right-click anywhere within the plot area to access the plot’s object inspection menu.

Adding a Strip Chart from the Navigation Pane or Ribbon This method lets you select objects and variables from the Variable Navigator: 1. Click Strip Charts in the Simulation navigation pane, or in the Dynamics ribbon tab | Tools | Strip Charts. 2. Click the Add button. A new strip chart is added to the list of available strip charts. 3. In the Sample Int. field, specify the amount of time in between taking data samples. The HYSYS default value is 20 seconds 4. Select the new strip chart and click Edit. 5. Use the Add button and the Variable Navigator to set up each variable that you want to appear in this strip chart.

Adding a Strip Chart from a Unit Operation Depending on the object property view, the strip chart sets contain variables appropriate for the object. For example, the strip chart set ToolTip Properties for a mixer will contain the following variables: Product Temperature, Product Pressure, and Product Molar Flow. The strip chart set ToolTip Properties for a separator will contain the following variables: Vessel Temperature, Vessel Pressure, and Liquid Volume Percent, as shown below. 1. Open the object’s property view, and access the Stripchart page or tab. 2. From the Variable Set drop-down list, select the desired strip chart. 3. Click the Create Stripchart button. The new strip chart property view

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appears. By default, the new stripchart is named

Hysys Unit Operations v10 Reference Guide

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