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Introduction to Flowsheet Simulation

Introduction to Flowsheet Simulation. Objective: Introduce general flowsheet simulation concepts and Aspen Plus features. Flowsheet Simulation. What is flowsheet simulation? Use of a computer program to quantitatively model the characteristic equations of a chemical process

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Introduction to Flowsheet Simulation

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  1. Introduction to Flowsheet Simulation Objective: Introduce general flowsheet simulation concepts and Aspen Plus features

  2. Flowsheet Simulation • What is flowsheet simulation? Use of a computer program to quantitatively model the characteristic equations of a chemical process • Uses underlying physical relationships • Mass and energy balance • Equilibrium relationships • Rate correlations (reaction and mass/heat transfer) • Predicts • Stream flowrates, compositions, and properties • Operating conditions • Equipment sizes Introduction to Aspen Plus

  3. Advantages of Simulation • Reduces plant design time • Allows designer to quickly test various plant configurations • Helps improve current process • Answers “what if” questions • Determines optimal process conditions within given constraints • Assists in locating the constraining parts of a process (debottlenecking) Introduction to Aspen Plus

  4. RECYCLE REACTOR COOL FEED SEP REAC-OUT COOL-OUT PRODUCT General Simulation Problem • What is the composition of stream PRODUCT? • To solve this problem, we need: • Material balances • Energy balances Introduction to Aspen Plus

  5. Approaches to Flowsheet Simulation • Sequential Modular • Aspen Plus is a sequential modular simulation program. • Each unit operation block is solved in a certain sequence. • Equation Oriented • Aspen Custom Modeler (formerly SPEEDUP) is an equation oriented simulation program. • All equations are solved simultaneously. • Combination • Aspen Dynamics (formerly DynaPLUS) uses the Aspen Plus sequential modular approach to initialize the steady state simulation and the Aspen Custom Modeler (formerly SPEEDUP) equation oriented approach to solve the dynamic simulation. Introduction to Aspen Plus

  6. Good Flowsheeting Practice • Build large flowsheets a few blocks at a time. • This facilitates troubleshooting if errors occur. • Ensure flowsheet inputs are reasonable. • Check that results are consistent and realistic. Introduction to Aspen Plus

  7. Important Features of Aspen Plus • Rigorous Electrolyte Simulation • Solids Handling • Petroleum Handling • Data Regression • Data Fit • Optimization • User Routines Introduction to Aspen Plus

  8. The User Interface Objective: Become comfortable and familiar with the Aspen Plus graphical user interface Aspen Plus References: User Guide, Chapter 1, The User Interface User Guide, Chapter 2, Creating a Simulation Model User Guide, Chapter 4, Defining the Flowsheet

  9. The User Interface Title Bar Run ID Menu Bar Reference: Aspen Plus User Guide, Chapter 1, The User Interface Next Button Tool Bar Status Area Model Menu Select Mode Model Library Tabs button Process Flowsheet Window Introduction to Aspen Plus

  10. RECYCLE REACTOR COOL FEED SEP REAC-OUT COOL-OUT PRODUCT Cumene Flowsheet Definition Flash2 Model RStoic Heater Model Model Filename: CUMENE.BKP Introduction to Aspen Plus

  11. Using the Mouse • Left button click - Select object/field • Right button click - Bring up menu for selected object/field, or inlet/outlet - Cancel placement of streams or blocks on the flowsheet • Double left click - Open Data Browser object sheet Reference: Aspen Plus User Guide, Chapter 1, The User Interface Introduction to Aspen Plus

  12. Graphic Flowsheet Operations • To place a block on the flowsheet: 1. Click on a model category tab in the Model Library. 2. Select a unit operation model. Click the drop-down arrow to select an icon for the model. 3. Click on the model and then click on the flowsheet to place the block. You can also click on the model icon and drag it onto the flowsheet. 4. Click the right mouse button to stop placing blocks. Introduction to Aspen Plus

  13. Graphic Flowsheet Operations (Continued) • To place a stream on the flowsheet: 1. Click on the STREAMS icon in the Model Library. 2. If you want to select a different stream type (Material, Heat or Work), click the down arrow next to the icon and choose a different type. 3. Click a highlighted port to make the connection. 4. Repeat step 3 to connect the other end of the stream. 5. To place one end of the stream as either a process flowsheet feed or product, click a blank part of the Process Flowsheet window. 6. Click the right mouse button to stop creating streams. Introduction to Aspen Plus

  14. Graphic Flowsheet Operations (Continued) • To display an Input form for a Block or a Stream in the Data Browser: 1. Double click the left mouse button on the object of interest. • To Rename, Delete, Change the icon, provide input or view results for a block or stream: 1. Select object (Block or Stream) by clicking on it with the left mouse button. 2. Click the right mouse button while the pointer is over the selected object icon to bring up the menu for that object. 3. Choose appropriate menu item. Reference: Aspen Plus User Guide, Chapter 4, Defining the Flowsheet Introduction to Aspen Plus

  15. Automatic Naming of Streams and Blocks • Stream and block names can be automatically assigned by Aspen Plus or entered by the user when the object is created. • Stream and block names can be displayed or hidden. • To modify the naming options: • Select Options from the Tools menu. • Click the Flowsheet tab. • Check or uncheck the naming options desired. Introduction to Aspen Plus

  16. VAP1 COOL VAP2 Flash2 FEED COOL Model Heater FL2 Flash2 LIQ1 Model Model LIQ2 Benzene Flowsheet Definition Workshop • Objective - Create a graphical flowsheet • Start with the General with English Units Template. • Choose the appropriate icons for the blocks. • Rename the blocks and streams. FL1 When finished, save in backup format (Run-ID.BKP). filename: BENZENE.BKP Introduction to Aspen Plus

  17. Basic Input Objective: Introduce the basic input required to run an Aspen Plus simulation Aspen Plus References: User Guide, Chapter 3, Using Aspen Plus Help User Guide, Chapter 5, Global Information for Calculations User Guide, Chapter 6, Specifying Components User Guide, Chapter 7, Physical Property Methods User Guide, Chapter 9, Specifying Streams User Guide, Chapter 10, Unit Operation Models User Guide, Chapter 11, Running Your Simulation

  18. The User Interface • Menus • Used to specify program options and commands • Toolbar • Allows direct access to certain popular functions • Can be moved • Can be hidden or revealed using the Toolbars dialog box from the View menu • Data Browser • Can be moved, resized, minimized, maximized or closed • Used to navigate the folders, forms, and sheets Introduction to Aspen Plus

  19. The User Interface (Continued) • Folders • Refers to the root items in the Data Browser • Contain forms • Forms • Used to enter data and view results for the simulation • Can be comprised of a number of sheets • Are located in folders • Sheets • Make up forms • Are selected using tabs at the top of each sheet Introduction to Aspen Plus

  20. The User Interface (Continued) • Object Manager • Allows manipulation of discrete objects of information • Can be created, edited, renamed, deleted, hidden, and revealed • Next Button • Checks if the current form is complete and skips to the next form which requires input Introduction to Aspen Plus

  21. The Data Browser Next sheet Go forward Go back Comments Parent button Units Previous sheet Status Next Menu tree Status area Description area Introduction to Aspen Plus

  22. Help • Help Topics • Contents - Used to browse through the documentation. The User Guides and Reference Manuals are all included in the help. • All of the information in the User Guides is found under the “Using Aspen Plus” book. • Index - Used to search for help on a topic using the index entries • Find - Used to search for a help on a topic that includes any word or words • “What’s This?” Help • Select “What’s This?” from the Help menu and then click on any area to get help for that item. Introduction to Aspen Plus

  23. Functionality of Forms • When you select a field on a form (click left mouse button in the field), the prompt area at the bottom of the window gives you information about that field. • Click the drop-down arrow in a field to bring up a list of possible input values for that field. • Typing a letter will bring up the next selection on the list that begins with that letter. • The Tab key will take you to the next field on a form. Introduction to Aspen Plus

  24. Basic Input • The minimum required inputs (in addition to the graphical flowsheet) to run a simulation are: • Setup • Components • Properties • Streams • Blocks • Data can be entered on input forms in the above order by clicking the Next button. • These inputs are all found in folders within the Data Browser. • These input folders can be located quickly using the Data menu or the Data Browser buttons on the toolbar. Introduction to Aspen Plus

  25. Status Indicators Symbol Status Input for the form is incomplete Input for the form is complete No input for the form has been entered. It is optional. Results for the form exist. Results for the form exist, but there were calculation errors. Results for the form exist, but there were calculation warnings. Results for the form exist, but input has changed since the results were generated. Introduction to Aspen Plus

  26. RECYCLE REACTOR COOL FEED SEP REAC-OUT COOL-OUT Q = 0 Btu/hr Pdrop = 0 psi PRODUCT C6H6 + C3H6 = C9H12 Benzene Propylene Cumene (Isopropylbenzene) 90% Conversion of Propylene Cumene Production Conditions P = 1 atm T = 220 F Q = 0 Btu/hr P = 36 psia T = 130 F Benzene: 40 lbmol/hr Pdrop = 0.1 psi Propylene: 40 lbmol/hr Filename: CUMENE.BKP Use the RK-SOAVE Property Method Introduction to Aspen Plus

  27. Setup • Most of the commonly used Setup information is entered on the Setup Specifications Global sheet: • Flowsheet title to be used on reports • Run type • Input and output units • Valid phases (e.g. vapor-liquid or vapor-liquid-liquid) • Ambient pressure • Stream report options are located on the Setup Report Options Stream sheet. Introduction to Aspen Plus

  28. Setup Specifications Form Introduction to Aspen Plus

  29. Stream Report Options • Stream report options are located on the Setup Report Options Stream sheet. Introduction to Aspen Plus

  30. Setup Run Types Introduction to Aspen Plus

  31. Setup Units • Units in Aspen Plus can be defined at 3 different levels: 1. Global Level (“Input Data” & “Output Results” fields on the Setup Specifications Global sheet) 2. Object level (“Units” field in the top of any input form of an object such as a block or stream 3. Field Level • Users can create their own units sets using the Setup Units Sets Object Manager. Units can be copied from an existing set and then modified. Introduction to Aspen Plus

  32. Components • Use the Components Specifications form to specify all the components required for the simulation. • If available, physical property parameters for each component are retrieved from databanks. • Pure component databanks contain parameters such as molecular weight, critical properties, etc. The databank search order is specified on the Databanks sheet. • The Find button can be used to search for components. • The Electrolyte Wizard can be used to set up an electrolyte simulation. Introduction to Aspen Plus

  33. Components Specifications Form Introduction to Aspen Plus

  34. Entering Components • The Component ID is used to identify the component in simulation inputs and results. • Each Component ID can be associated with a databank component as either: • Formula: Chemical formula of component (e.g., C6H6)(Note that a suffix is added to formulas when there are isomers, e.g. C2H6O-2) • Component Name: Full name of component (e.g., BENZENE) • Databank components can be searched for using the Find button. • Search using component name, formula, component class, molecular weight, boiling point, or CAS number. • All components containing specified items will be listed. Introduction to Aspen Plus

  35. Find • Find performs an AND search when more than one criterion is specified. Introduction to Aspen Plus

  36. Databank Contents Use PURE10 Data from the Design Institute for Physical Primary component databank in Property Data (DIPPR) and AspenTech Aspen Plus AQUEOUS Pure component parameters for ionic and Simulations containing molecular species in aqueous solution electrolytes SOLIDS Pure component parameters for strong Simulations containing electrolytes, salts, and other solids electrolytes and solids INORGANIC Thermochemical properties for inorganic Solids, electrolytes, and components in vapor, liquid and solid states metallurgy applications PURE93 Data from the Design Institute for Physical For upward compatibility Property Data (DIPPR) and AspenTech delivered with Aspen Plus 9.3 PURE856 Data from the Design Institute for Physical For upward compatibility Property Data (DIPPR) and AspenTech delivered with Aspen Plus 8.5-6 ASPENPCD Databank delivered with Aspen Plus 8.5-6 For upward compatibility Pure Component Databanks • Parameters missing from the first selected databank will be searched for in subsequent selected databanks. Introduction to Aspen Plus

  37. Properties • Use the Properties Specifications form to specify the physical property methods to be used in the simulation. • Property methods are a collection of models and methods used to describe pure component and mixture behavior. • Choosing the right physical properties is critical for obtaining reliable simulation results. • Selecting a Process Type will narrow the number of methods available. Introduction to Aspen Plus

  38. Properties Specifications Form Introduction to Aspen Plus

  39. Streams • Use Stream Input forms to specify the feed stream conditions and composition. • To specify stream conditions enter two of the following: • Temperature • Pressure • Vapor Fraction • To specify stream composition enter either: • Total stream flow and component fractions • Individual component flows • Specifications for streams that are not feeds to the flowsheet are used as estimates. Introduction to Aspen Plus

  40. Streams Input Form Introduction to Aspen Plus

  41. Blocks • Each Block Input or Block Setup form specifies operating conditions and equipment specifications for the unit operation model. • Some unit operation models require additional specification forms • All unit operation models have optional information forms (e.g. BlockOptions form). Introduction to Aspen Plus

  42. Block Form Introduction to Aspen Plus

  43. Starting the Run • Select Control Panel from the View menu or press the Next button to be prompted. • The simulation can be executed when all required forms are complete. • The Next button will take you to any incomplete forms. Introduction to Aspen Plus

  44. Control Panel • The Control Panel consists of: • A message window showing the progress of the simulation by displaying the most recent messages from the calculations • A status area showing the hierarchy and order of simulation blocks and convergence loops executed • A toolbar which you can use to control the simulation Introduction to Aspen Plus

  45. Reviewing Results • History file or Control Panel Messages • Contains any generated errors or warnings • Select History or Control Panel on the View menu to display the History file or the Control Panel • Stream Results • Contains stream conditions and compositions • For all streams (/Data/Results Summary/Streams) • For individual streams (bring up the stream folder in the Data Browser and select the Results form) • Block Results • Contains calculated block operating conditions (bring up the block folder in the Data Browser and select the Results form) Introduction to Aspen Plus

  46. Benzene Flowsheet Conditions Workshop • Objective: Add the process and feed stream conditions to a flowsheet. • Starting with the flowsheet created in the Benzene Flowsheet Definition Workshop (saved as BENZENE.BKP), add the process and feed stream conditions as shown on the next page. • Questions: 1. What is the heat duty of the block “COOL”? _________ 2. What is the temperature in the second flash block “FL2”? _________ Note: Answers for all of the workshops are located in the very back of the course notes in Appendix C. Introduction to Aspen Plus

  47. VAP1 COOL VAP2 FL1 FEED COOL FL2 LIQ1 LIQ2 Benzene Flowsheet Conditions Workshop T = 100 F P = 500 psia Feed T = 200 F P = 1 atm T = 1000 F Pdrop = 0 Q = 0 P = 550 psia Hydrogen: 405 lbmol/hr Methane: 95 lbmol/hr Benzene: 95 lbmol/hr Toluene: 5 lbmol/hr When finished, save as filename: BENZENE.BKP Use the PENG-ROB Property Method Introduction to Aspen Plus

  48. Unit Operation Models Objective: Review major types of unit operation models Aspen Plus References: User Guide, Chapter 10, Unit Operation Models Unit Operation Models Reference Manual

  49. Unit Operation Model Types • Mixers/Splitters • Separators • Heat Exchangers • Columns • Reactors • Pressure Changers • Manipulators • Solids • User Models Reference: The use of specific models is best described by on-line help and the documentation. Aspen Plus Unit Operation Models Reference Manual Introduction to Aspen Plus

  50. Mixers/Splitters Introduction to Aspen Plus

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