A Guide to Using The Aspen OLI Interface An Overview of the Aspen OLI Interface 1-1 Chapter 1 An Overview of the Aspen OLI Interface History • Dupont 25 year history using OLI electrolytes program. • 1995 switched to Aspen as their process simulator. • Wanted the capability to use OLI electrolytes from ASPEN. • In 1996 Aspen V-8.2 was interfaced (no Model Manager) • In 1997 Aspen V-9.x with Model Manager. • Currently interfacing with Aspen PLUS V7 (2008) Advantages of Aspen OLI • User Interface • Learn one flowsheeting system • Multiple Property Options in same flowsheet • Well established Non-electrolyte capability • Sizing • Costing • Two Software Venders
Transcript
A Guide to Using The Aspen OLI Interface An Overview of the Aspen OLI Interface 1-1
Chapter 1 An Overview of the Aspen OLI Interface
History • Dupont 25 year history using OLI electrolytes program.
• 1995 switched to Aspen as their process simulator.
• Wanted the capability to use OLI electrolytes from ASPEN.
• In 1996 Aspen V-8.2 was interfaced (no Model Manager)
• In 1997 Aspen V-9.x with Model Manager.
• Currently interfacing with Aspen PLUS V7 (2008)
Advantages of Aspen OLI • User Interface
• Learn one flowsheeting system
• Multiple Property Options in same flowsheet
• Well established Non-electrolyte capability
• Sizing
• Costing
• Two Software Venders
1-2 An Overview of the Aspen OLI Interface A Guide to Using The Aspen OLI Interface
Disadvantages of Aspen OLI
• No Corrosion
• No Bio-reactors
• No Ion-exchange
• No Surface Complexation
• No Scaling Tendencies
• Two Software Venders
Aspen OLI Interface Layout
Figure 1-1 The layout of the Aspen OLI Interface
A Guide to Using The Aspen OLI Interface An Overview of the Aspen OLI Interface 1-3
Aspen OLI Unit Operations
•MIXERS
•FSPLIT
•SEP
•SEP2
•HEATER
•FLASH2
•FLASH3
•HEATX
•MHEATX
•RADFRAC
•RSTOIC
•RYIELD
•RCSTR
•RPLUG
•PUMP
•COMPR
1-4 An Overview of the Aspen OLI Interface A Guide to Using The Aspen OLI Interface
Aspen Property Set
Figure 1-2 OLI Property Set, the circled areas show that OLI is enabled
A Guide to Using The Aspen OLI Interface An Overview of the Aspen OLI Interface 1-5
A Guide to Using The Aspen OLI Interface An Overview of the Aspen OLI Interface 1-7
Using the Aspen OLI Interface • New property option in ASPEN named OLI:
PROPERTIES OLI CHEMISTRY=xxxxx TRUE-COMPS=YES
• The following ASPEN paragraphs are created when the chemistry model is generated:
DATABANKS PROP-DATA
COMPONENTS PROPERTIES
CHEMISTRY PROP-SET pH
• ASPEN user is then required to add the additional paragraphs to run the simulation
such as:
FLOWSHEET
STREAMS
BLOCKS
ESP-NAME DB 8-CHAR ASP-ALIAS ASP-NAME ================ = ====== ========= =========================== AR P AR AR ARGON BCL3 V BCL3 BCL3 BORON-TRICHLORIDE BF3 V BF3 BF3 BORON-TRIFLUORIDE BR2 V BR2 BR2 BROMINE CLNO V CLNO CLNO NITROSYL-CHLORIDE CL2 P CL2 CL2 CHLORINE PCL3 V PCL3 CL3P PHOSPHORUS-TRICHLORIDE SICL4 V SICL4 CL4SI SILICON-TETRACHLORIDE D2 V D2 D2 DEUTERIUM D2O V D2O D2O DEUTERIUM-OXIDE
F2 V F2 F2 FLUORINE NF3 V NF3 F3N NITROGEN-TRIFLUORIDE SIF4 V SIF4 F4SI SILICON-TETRAFLUORIDE SF6 V SF6 F6S SULFUR-HEXAFLUORIDE HBR V HBR HBR HYDROGEN-BROMIDE HCL P HCL HCL HYDROGEN-CHLORIDE HF P HF HF HYDROGEN-FLUORIDE AGION P AG+ AG+ AG+ AGCL2ION P AGCL2- AGCL2-2 AGCL2-- AGSO4ION P AGSO4- AGSO4- AGSO4- ALION P AL+3 AL+3 AL+++ ALFION P ALF+2 ALF+2 ALF++ ALF2ION P ALF2+ ALF2+ ALF2+
1-8 An Overview of the Aspen OLI Interface A Guide to Using The Aspen OLI Interface
Potential Problems •Mixing property options in the same flowsheet The user can mix property options in the same flowsheet, using OLI in one block and an Aspen sysopt such as SYSOP3 in another block. However, the user must be aware of the potential problem of enthalpy mis-matches in switching property options. Even though the base enthalpy for both Aspen and OLI is the heat of formation of the pure component at 25 C, a mis-match will occur due to differences in heat capacity and excess enthalpy calculations. If an isothermal calculation is made at the point of property option change, the effect will be to have an artificial duty on the block. An adiabatic calculation could cause major problems in convergence and result in erroneous results.
• Chemistry model location (xxxx.DBS file) By default ASPEN looks for the .DBS file in the directory where the BKP file has been created.
• 8 Character Component Names at chemistry model generation, an 8 character name will be created for each species and cross referenced to both OLI component names and Aspen component names. This cross referencing is made based on a table (OLIASP.XRF) supplied with the installation. Do Not change the names after the chemistry model is created. It is okay to add additional names to the components paragraph providing these components will have zero flow rates for any block using the OLI property option.
• Chemistry ParagraphThe chemistry paragraph created and placed in the Aspen input file is only used by the RADFRAC block. All other blocks chemistry is define by the information in the xxx.DBS file
Added Unit Blocks (OLI)
•Four phase flash block (EFLASH)
•OLI Distillation program (EFRACH)
•Can only be used through command line (No Model Manager)
•New run command (RUNASP)
Reads xxxx.ASP file and converts keyword input to positional input and outputs xxxx.INP.
A Guide to Using The Aspen OLI Interface An Overview of the Aspen OLI Interface 1-9
Executes the standard Aspen run command to run the simulation.
Figure 1-3 EFLASH unit operation
Figure 1-4 EFRACH Block
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Chapter 2 ASPEN Neutralization Flowsheet
A Tour of the OLI-ASPEN Interface
The following example is flowsheet simulation of an acid-base neutralization process. An acid stream and a base stream are mixed together and then caustic is added to raise the pH to 9. Solid NACL is added to precipitate out Na2SO4. The resulting stream is split, removing 75% and recycling 25%.
A Guide to Using The Aspen OLI Interface ASPEN Neutralization Flowsheet 2-11
Generating Chemistry Model
There are two methods to create an OLI chemistry model to be used with Aspen PLUS. These are the Chemistry Wizard and the OLI Engine1. We will concentrate on the OLI Chemistry Wizard. Use the Start Button and locate the OLI Chemistry Wizard. Typical installation paths will put the program here: Start > Programs > AspenTech > Aspen Engineering Suite> Aspen OLI 2006.5
Figure 2-1 The Aspen OLI Splash Screen
This screen will close on its own in a few seconds or you can click to clear the image.
1 The OLI Engine chemistry generator is supplied with the OLI Alliance Suite for Aspen PLUS and is very similar to the chemistry generator used for ESP. This will be shown in Chapter 6.
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The Chemistry Wizard information dialog is now displayed. You can enter the name of the model and change the location where the model files will be located. Here we will enter the name Neutral1for the model name and change the location of the files.
Figure 2-2 Specifying the model name and location
Click the Next> button to continue
Figure 2-3 Chemistry Model name specified
A Guide to Using The Aspen OLI Interface ASPEN Neutralization Flowsheet 2-13
Here we can select the thermodynamic framework. There are two offered by OLI. The traditional aqueous model and the mixed-solvent electrolyte framework. This latter framework is also known as the H3O+ (hydronium ion) framework.2 We can also select databases in addition to the PUBLIC database. These databases listed contain data that limited to a more specific region of thermodynamic space than the PUBLIC database or contains data that is missing from the public database. For this example we will only use the PUBLIC database. Click the Next> button to continue
2 We will discuss the MSE framework in Chapter 7
Figure 2-4 Selecting thermodynamic framework and databases
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Figure 2-5 Adding components
We are now ready to add the components for this example. Click the Add button.
A Guide to Using The Aspen OLI Interface ASPEN Neutralization Flowsheet 2-15
Figure 2-6 Select Components
We now need to add our components of ammonia (NH3), carbon dioxide (CO2), sulfur dioxide (SO2), hydrochloric acid (HCL), sulfuric acid (H2SO4) and sodium hydroxide (NAOH). We can scroll through the list or enter the component ID and let the software find the component. We will try the latter technique, enter the component ID NH3
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Figure 2-7 Adding NH3, ammonia
You can see that the screen automatically scrolled as you entered letters. The current component NH3 is highlighted. Click the Add button. Repeat this action for the remaining components. Click the Close button when done.
A Guide to Using The Aspen OLI Interface ASPEN Neutralization Flowsheet 2-17
Figure 2-8 the added components
Click the Next> button.
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Figure 2-9 adding redox
On this screen we can add oxidation and reduction to the chemistry. We will not do so for this example. Click the Next> button.
A Guide to Using The Aspen OLI Interface ASPEN Neutralization Flowsheet 2-19
Figure 2-10 Selecting phases, including solids
On this screen we can enable vapor and second liquid (non-aqueous) phases. By default the vapor phase is enabled and the second liquid phase is disabled. We can also turn off all potential solid phases or select individual solids to exclude. Occasionally the user will have prior knowledge of which solid phases will be present. Eliminating solids that are not possible can dramatically increase the execution speed of the program. Click Next> to continue.
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Figure 2-11 Aspen Alias names
Many times OLI will have a component that Aspen PLUS will not. For those cases an alias name has to be provided to allow the two programs to properly communicate. As you can see in this example, there is no AspenPLUS alias for NAOH. We must provide one. Enter the alias NAOH.
Figure 2-12 Alias Entered
A Guide to Using The Aspen OLI Interface ASPEN Neutralization Flowsheet 2-21
Click the Next> button.
Figure 2-13 BKP file options
OLI initially communicates to Aspen PLUS via the BKP file. We will shortly create a flowsheet without any unit operations. The BKP file will initially have the same name as the chemistry model but you may change the name if you wish. A second option is to allow the solid salts to precipitate. This is the default option. Alternatively you can dramatically increase the speed of execution by setting the salts to be dissociated. It is recommended for OLI models that you accept the default choices. Click the Next> button.
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Figure 2-14 Almost done
We are almost done with the chemistry model generation. This is the summary screen of what we have selected. Please review it to make sure you have made the choices you require. Click the Generate Files Now button. If the model was successfully generated you will receive this message:
Figure 2-15 completed
Click the OK button.
A Guide to Using The Aspen OLI Interface ASPEN Neutralization Flowsheet 2-23
Figure 2-16 Done
We are now done with the chemistry model generation. Notice that the Generate Files Now button and the Next> button are gray. Click the Finish button. We create a BKP file and an ASP file. We will use the BKP file in a moment. The ASP file is the old Aspen INP file. We have renamed the file from INP to ASP since OLI also uses a file with extension INP.3 Here is the contents of the file. It can be renamed to INP to be used with the Aspen PLUS Simulation Engine.
File NEUTRAL.ASP TITLE " " ; DESCRIPTION " " ; RUN-CONTROL MAX-TIME=36000 ; HISTORY MSG-LEVEL SIM-LEVEL=4 STREAM-LEVEL=4 ; IN-UNITS ENG OUT-UNITS ENG ; DATABANKS ASPENPCD /SOLIDS /AQUEOUS /PURECOMP /INORGANIC ; COMPONENTS H2O H2O / CO2 CO2 / H2SO4 H2SO4 / HCL HCL / NH3 H3N /
3 The INP file is used with OLI’s ProChem software.
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2-28 ASPEN Neutralization Flowsheet A Guide to Using The Aspen OLI Interface
; FLOWSHEET ;
A Guide to Using The Aspen OLI Interface ASPEN Neutralization Flowsheet 2-29
Creating the Aspen Flowsheet
It is beyond the scope of this manual to instruct the user in how to run Aspen PLUS. We will just concentrate on the issues unique to OLI. Start Aspen PLUS in the normal manner. We first need to load the BKP file we just created.
Figure 2-17 Locating the BKP file
Select More Files… and then click the OK button.
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Figure 2-18 standard windows open dialog
Locate the folder where you stored the OLI Chemistry Wizard files and the BKP file. Select the file and click Open. Accept whatever local or network setting you must to activate the Aspen PLUS program. You may see the following warning:
Figure 2-19 Compatibility warning
A Guide to Using The Aspen OLI Interface ASPEN Neutralization Flowsheet 2-31
The BKP file generated by OLI is a very simple format file without any of the features available in Aspen PLUS 2006 or later. It is safe to select Maintain complete upward compatibility but you may use any new features that are available. Click the OK button.
Figure 2-20 A blank flowsheet
We are now presented with a blank flowsheet. We will create the following process:
2-32 ASPEN Neutralization Flowsheet A Guide to Using The Aspen OLI Interface
Figure 2-21 Neutral 1 Process
This process mixes a basic stream (1) with an acidic stream (2) adiabatically in block B1. The resultant vapor stream (3) is drawn off and the mixed liquid (4) is neutralized with a sodium hydroxide stream (5) adiabatically in block B2. A design specification is that stream 7 is to be held to a pH of 9.0 within 0.01 pH units. The following tables contain the Stream conditions: Stream 1 2 5 Temperature (oC) 40 25 30 Pressure (atm) 1 1 1 Total flow (lbmole/hr) 200 150 100 H2O (lbmole/hr) 55.5 55.5 55.5 NH3 1 0 0 CO2 0.1 0 0 SO2 0.1 0 0 HCL 0 0.1 0 H2SO4 0 1.0 0 NAOH 0 0 1 Block B1 B2 Duty (Btu/hr) 0 0 Pressure (atm) 1 1 Design Specification DS-1 Variable Name PH Target 9.0 Tolerance 0.01
A Guide to Using The Aspen OLI Interface ASPEN Neutralization Flowsheet 2-33
A Tour of the OLI-ASPEN Interface (RADFRAC example) The following example is a simulation of a Chlorine scrubber. Caustic is used to remove chlorine from a gas stream. The caustic feed rate to the column is adjusted to reduce the chlorine in the column overhead gas to .5 moles/hr.
Generating Chemistry Model
Using the OLI Chemistry Wizard, create a chemistry model with the following components. We recommend the name of the model to be CHLORINE H2O, CO2, CL2, N2, NAOH
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Creating the Aspen Flowsheet
Start Aspen normally and open the Chlroine.BKP file just created.
Create the following flowsheet using the Model Manager
A Guide to Using The Aspen OLI Interface ASPEN Emergency Chlorine Scrubber Flowsheet 3-39
Caustic Feed Stream (Stream 1)
Feed Stream (Stream 2)
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RADFRAC (Block B1) configuration (5 stages)
A Guide to Using The Aspen OLI Interface ASPEN Emergency Chlorine Scrubber Flowsheet 3-41
RADFRAC (Block B1) streams
RADFRAC (Block B1) pressure
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RADFRAC (Block B1) estimates
A Guide to Using The Aspen OLI Interface ASPEN Emergency Chlorine Scrubber Flowsheet 3-43
Design Specs for BLOCK B2
Enter a value of 0.5 for the target. Now click on the Component tab.
3-44 ASPEN Emergency Chlorine Scrubber Flowsheet A Guide to Using The Aspen OLI Interface
Vary flow rate of feed stream 1 to meet spec.
A Guide to Using The Aspen OLI Interface ASPEN Emergency Chlorine Scrubber Flowsheet 3-45
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Chapter 4 ASPEN Amine Gas Cleanup Flowsheet
A Tour of the OLI-ASPEN Interface
The following example is a flowsheet simulation to remove H2S and CO2 from a hydrocarbon stream using DEA. The H2S and CO2 are absorbed in a column by the DEA at a pressure of 20 atmospheres. The pressure is let down to 1.5 atmospheres in a flash drum. The H2S and CO2 are then stripped from the DEA in a column by heating. The clean DEA is then recycled back to the absorber. Both water and DEA are added as make-up streams
A Guide to Using The Aspen OLI Interface ASPEN Amine Gas Cleanup Flowsheet 4-47
Generating Chemistry Model
Create a chemistry model using the OLI Chemistry Wizard for Aspen PLUS. We recommend that the name of the model be called DEA. Enter the component names: H2O, CO2, H2S, CH4, C2H6, C3H8, C4H10, and DEXH5 When done entering the component names, click the Next button to continue. You may be required to fill in some blank names on the AspenPlus Component ID & Alias dialog. If so, use the same name as the AspenPlus ID
Figure 4-1 Missing Aspen Alias
Figure 4-2 Filled in Alias
5 This the OLI name for diethanolamine.
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Click the Next button until the model is complete. Click the Finish button when it presents itself. The Aspen backup format file will be created and will be named DEA.BKP. This file can be opened in ASPEN Model Manager.
Creating the Aspen Flowsheet
Start up the ASPEN PLUS by double clicking on the ASPEN icon: Select “more files” and locate the file dea.bkp and open this file. Select Data on the action bar, then Components should show the species created from ESP.
Create the following flowsheet using the Model Manager
A Guide to Using The Aspen OLI Interface ASPEN Amine Gas Cleanup Flowsheet 4-49
Gas Feed Stream (Stream 1)
Water Maker-up Stream (Stream 11)
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Dea Make-up Stream (Stream 12)
Tear Stream Guess (Stream 6)
A Guide to Using The Aspen OLI Interface ASPEN Amine Gas Cleanup Flowsheet 4-51
Dea Absorber – RADFRAC (Block B1) configuration
Dea Absorber – RADFRAC (Block B1) streams
The Feed and Product stages may appear in a different order depending on how you created the flowsheet.
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Dea Absorber – RADFRAC (Block B1) pressure
Dea Absorber – RADFRAC (Block B1) estimates
A Guide to Using The Aspen OLI Interface ASPEN Amine Gas Cleanup Flowsheet 4-53
Dea Absorber – RADFRAC (Block B1) convergence
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Flash Tank – FLASH2 (Block B3)
A Guide to Using The Aspen OLI Interface ASPEN Amine Gas Cleanup Flowsheet 4-55
Dea Stripper – RADFRAC (Block B2) configuration
Dea Stripper – RADFRAC (Block B2) streams
The Feed and Product stages may appear in a different order depending on how you created the flowsheet.
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Dea Stripper – RADFRAC (Block B2) pressure
A Guide to Using The Aspen OLI Interface ASPEN Amine Gas Cleanup Flowsheet 4-57
Dea Stripper – RADFRAC (Block B2) estimates
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Dea Stripper – RADFRAC (Block B2) convergence
A Guide to Using The Aspen OLI Interface ASPEN Amine Gas Cleanup Flowsheet 4-59
Add Make up Water MIXER (Block B4)
Add Make up DEA – HEATER (Block B6)
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We will now add a design specification to control the amount of water in the process. Open the Data Browser and find the Flowsheeting options. Open the Flowsheeting options to Design Spec
Click the New… button and enter the ID of DS-1
Enter the name for the water flow rate as WATFL.
A Guide to Using The Aspen OLI Interface ASPEN Amine Gas Cleanup Flowsheet 4-61
Click off the variable name and then reselect it. Then click the Edit button. Make the changes as indicated:
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Click the close button.
A Guide to Using The Aspen OLI Interface ASPEN Amine Gas Cleanup Flowsheet 4-63
Design_Spec DS-1 spec
4-64 ASPEN Amine Gas Cleanup Flowsheet A Guide to Using The Aspen OLI Interface
Design_Spec DS-1 vary
We will now create a second design specification to control the amount of diethanolamine (DEXH) in the recycle loop. Click on the Design Spec category in the tree view.
A Guide to Using The Aspen OLI Interface ASPEN Amine Gas Cleanup Flowsheet 4-65
Click the New…button. Accept the default name for the design specification and then click the OK button. We will now define three variables for diethanolamine. These variables represent the three forms of diethanolamine in the process. The first is the variable DEXFL which is defined to be the neutral form of diethanolamine (DEXH). The second variable is DEXCO which is the amine which has absorbed a carbon dioxide molecule (DEXCO2-). The final variable is DEXH2 which is the protonated form of the amine (DEXH2+). We will then control via the design specification on the sum of these three amine forms.
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Click on the New button to add the first variable DEXFL
Click OK
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Click Close and repeat the steps to add the variable DEXCO
4-68 ASPEN Amine Gas Cleanup Flowsheet A Guide to Using The Aspen OLI Interface
Finally repeat for the final variable DEXH2
When complete, your define screen should look similar to the following:
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Design-Spec DS-2 define
Click on the Spec tab
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Design-Spec DS-2 spec
Click on the Vary tab.
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Design-Spec DS-2 vary
We are now ready to run the simulation. Execute the process as you would normally.
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A Guide to Using The Aspen OLI Interface EFLASH and EFRACH 5-75
Chapter 5 EFLASH and EFRACH
Overview Two OLI Electrolyte blocks have been added to enable the use of OLI’s 4 phase flash (EFLASH) and OLI’s distillation tower (FraChem). These two blocks were added through ASPEN user added blocks capability and are available via the Library>Reference feature of Aspen PLUS.
The ability to separate a 4 phase system into 4 streams does not exist in Aspen PLUS. This operation allows you to make complete phase separation.
EFLASH (Electrolyte Flash)
EFLASH
Four Outlet MaterialStreams
FEEDS
HEAT
VAPOR (1)
AQUEOUS (2)
ORGANIC (3)
SOLID (4)
HEAT
.
.
.
Figure 5-1 EFLASH diagram
Three Outlet Material Streams
(1) - VAPOR (2) - AQUEOUS & ORGANIC (3) - SOLID
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Two Outlet Material Streams
(1) - VAPOR (2) - AQUEOUS & ORGANIC & SOLID
One Outlet Material Stream
(1) - ALL PHASES
Example In this case we will create a chemistry model as described in early sections. This model will contain H2O, NaCl, C10H22 and N2. When prompted, select the second organic liquid phase as well as the aqueous, vapor and solid phases.
Start Aspen PLUS as you would normally and open the BKP file you just created using either the OLI Chemistry Wizard or OLI Chemistry Generator.
Select the Library menu item.
Select References…
A Guide to Using The Aspen OLI Interface EFLASH and EFRACH 5-77
If the OLI option has been purchased and the OLI Alliance Suite for Aspen PLUS has been installed then the OLI option will appear in this dialog. Check the OLI box and then click OK.
The library has not been added to the library tool bar at the bottom of the Aspen PLUS user interface.
Use the scroll buttons to find the OLI Library (it will be at the end of this list)
The icons for the library appear at the left hand side.
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The EFLASH and EFRACH (a/k/a FraChem) appear on this library pallete. Like any other icon, we can drag the icon to the work sheet. Create the following worksheet:
B1: Eflash4 B2: Flash3 Enter the following composition for STREAM 1 Temperature 25 C Pressure 1 ATM H2O 100 kmol/hr C10H22 10 kmol/hr N2 1 kmol/hr NaCl 20 kmol/hr
A Guide to Using The Aspen OLI Interface EFLASH and EFRACH 5-79
Double-click the block B1
Add the indicated temperature and pressure in the correct units.
Click on the Stream Definitions tab.
Fill out the four streams.
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Close the block and open Block B2
Change the default Temperature value to Heat Duty and set a value of 0.0. Change the Pressure to 1 ATM. Close the block. Run the simulation. We have separated the solid phase into STREAM 4, the vapor into STREAM 2 and a mixed stream into STREAM 3. The Mixed Stream is then further separated by phase.
A Guide to Using The Aspen OLI Interface EFLASH and EFRACH 5-81
Density lbmol/cuft 0.307609 2.55E‐03 2.078688 2.311291 0.3239216 3.741882
Density lb/cuft 9.572315 0.0714104 60.90083 135.0787 46.00545 75.01889
Average MW 31.11845 27.9803 29.29772 58.44297 142.0265 20.04844
Liq Vol 60F cuft/hr 1.882868 11.88138 0 68.63595
*** LIQUID PHASE ***
PH 6.945542 6.945544 6.9455
Input Language
5-82 EFLASH and EFRACH A Guide to Using The Aspen OLI Interface
BLOCK blockid EFLASH PARAM keyword=value Optional keywords: TEMP PRES DUTY VFRAC PH MOLEC PHASE PARAM Default flash is adiabatic at inlet pressure. The user must specify two of the state
variables. The valid combinations are: TEMP, PRES - Constant TP flash DUTY, PRES - Adiabatic flash to calculate TEMP DUTY, TEMP - Adiabatic flash to calculate PRES VFRAC, PRES - Fixed vapor fraction, calculate TEMP VFRAC, TEMP - Fixed vapor fraction, calculate PRES PH, PRES - Fixed pH, calculate TEMP PH, TEMP - Fixed pH, calculate PRES TEMP - Temperature PRES - Pressure, zero or negative indicates pressure drop VFRAC - Molar vapor fraction DUTY - Heat duty PH - pH of the outlet MOLEC - Default outlet streams are in the true ionic form provided all
species names have been defined in the COMPONENTS paragraph. If MOLEC is specified in the PARAM sentence, stream output will be in molecular form (all ions combined to molecular components)
PHASE - No equilibrium calculation, evaluate enthalpy at T,P and Specified
phase conditions (V,L,S) PHASE=V - ALL VAPOR PRODUCT PHASE=L - ALL LIQUID PRODUCT PHASE=S - ALL SOLID PRODUCT
A Guide to Using The Aspen OLI Interface EFLASH and EFRACH 5-83
EFLASH Examples _______________________________________________________________________ Example 1 Flash at a temperature=100 and pressure=14.7. Put vapor product in stream S1, aqueous product in stream S2, organic liquid phase in stream S3 and solid phase in stream S4.. FLOWSHEET BLOCK FLSH IN=FEED1 FEED2 OUT=S1 S2 S3 S4 BLOCK FLSH EFLASH PARAM TEMP=100 PRES=1 _______________________________________________________________________ Example 2 Adiabatic flash to calculate temperature. All phases put in stream S1. FLOWSHEET BLOCK FLSH IN=FEED1 FEED2 OUT=S1 BLOCK FLSH EFLASH PARAM DUTY=0. PRES=0 . . Example 3 Flash to a vapor fraction=.2 at the inlet pressure. Put vapor phase in steam S1, aqueous and organic in stream S2 and solid in S3. FLOWSHEET BLOCK FLSH IN=FEED1 FEED2 OUT=S1 S2 S3 BLOCK FLSH EFLASH PARAM VFRAC=.2 PRES=0. _______________________________________________________________________
5-84 EFLASH and EFRACH A Guide to Using The Aspen OLI Interface
EFLASH Examples (Continued) _______________________________________________________________________ Example 4 All vapor stream at 300 F and 14.7 psia FLOWSHEET BLOCK FLSH IN=FEED1 OUT=S1 BLOCK FLSH EFLASH PARAM TEMP=300 PRES=14.7 PHASE=V NOTE: There is no equilibrium calculation in this block. The outlet is assumed to be vapor at this condition and the
enthalpy is evaluated at the specified temp and pres. ________________________________________________________________________
A Guide to Using The Aspen OLI Interface EFLASH and EFRACH 5-85
EFRACH (Electrolyte Distillation)
2
3
1
N
DECANTOR
FEEDS
PRODUCTS
VAPOR OR LIQUID
HEAT HEAT
HEATHEAT
HEAT HEAT
Figure 5-2 EFRACH diagram
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Input Language
BLOCK blockid EFRACH PARAM keyword=value keyword: NSTAGE optional keyword: MAXIT NPRINT NCOLTY NINIF FEEDS sid stage [phase] /... PRODUCTS sid stage [phase] keyword=value /... optional keyword: MOLE-FLOW P-SPEC stage pres /... SC-REFLUX keyword=value keyword: MOLE-D MOLE-LN RR TEMP HEATERS stage duty /... STAGE-EFF stage eff /... DECANTER T-EST stage temp /... V-EST stage mole-flow /... L-EST stage mole-flow /... VARY varyno vartype keyword=value varytype: DUTY Q1 QN FEED-FLOW MOLE-LPROD MOLE-VPROD keyword: STAGE SPEC specno spectype value keyword=value spectype: TEMP MOLE-FLOW MASS-FLOW MOLE-FRAC MASS-FRAC keyword: STAGE PHASE COMPS PUMP-AROUNDS FROM=stage TO=stage MOLE-FLOW=value EFRACH (Continued) _______________________________________________________________________ PARAM NSTAGE is required, all other parameters are optional. NSTAGE - Number of stages in the column, including condenser and reboiler; must be greater than 1. and less then 100. NPRINT - Controls the amount of print to the history file. 1 - print input and final profiles
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2 - same as 1 with intermediate column profiles (default) 3 - same as 2 with full intermediate stage compositions NCOLTY - Indicates the type of column 0 - electrolyte column with two or three phase (default) (number of phases is controlled by chemistry model) 2 - electrolyte extraction column MAXIT - Maximum number of iterations before stopping. (default=30) NINIF - Tower initialization flag 0 - Use previous results except for first time (default) 1 - Re-initialize tower each time in recycle loops 2 - Use previous results all the time _______________________________________________________________________ FEEDS Used to enter inlet material and heat stream locations. Liquid feeds are introduced onto the specified stage, vapor feeds go to the stage above the specified stage. A mixed phase feed will have the liquid portion to the specified stage and the vapor portion to the stage above. A vapor stream to the bottom stage is specified with as STAGE= (NSTAGE+1). A maximum of ten feed streams can be specified. (Heat streams must be specified last) sid - Stream ID stage - Stage number from the top phase - option entry to specify phase condition of feed. (default is to calculate based on temp and pres)
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EFRACH (Continued) _______________________________________________________________________ PRODUCTS Two product streams are required, a distillate and a bottoms. In addition, vapor side draws and liquid side draws may be specified for a maximum of ten product streams. (Heat streams must be specified last) sid - Stream ID stage - Stage number from the top phase - Indicates phase condition of product stream (V or L). phase=L .... all liquid product phase=V .... all vapor product MOLE-FLOW - Mole flow rate of product stream, required for all side stream draw-offs. The distillate and bottoms rate should not be specified.
P-SPEC Used to set the column pressure profile. At least on pressure is required. Only the top two stages and the bottom stage are used. The remaining stage are calculated by interpolation. stage - Stage number from the top pres - Pressure
SC-REFLUX Used to specify a subcooled condenser, both the distillate and reflux are subcooled. The default is a partial condenser with a vapor distillate and liquid reflux. One of the following is required (MOLE-D, MOLE-LN,or RR). The temperature is calculated from the specified heat duty or it may also be specified. TEMP - Condenser temperature MOLE-D - Distillate rate out top of column MOLE-LN - Reflux rate from condenser to top stage of the column RR - Reflux ratio (Distillate rate/Reflux rate) EFRACH (Continued) _______________________________________________________________________ HEATERS May be used to enter the heater stage location and duty. Inlet heat streams may be used in place of heater duty. Any inlet heat streams will be added to the duty. A HEATER record is required if the column has a condenser or reboiler. stage - Stage number from the top
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duty - Heat duty _______________________________________________________________________ STAGE-EFF May be used to enter Murphree stage efficiencies. These efficiencies are applied to each component on the stage. Any missing stages will be linear interpolated; therefore, the top and bottom stages must be supplied. stage - Stage number from the top eff - Efficiency (default=1.0) _______________________________________________________________________ DECANTER A decanter may be specified for the condenser. The organic phase is drawn off as distillate and the aqueous phase is refluxed back to the column. When using this option, a temperature spec needs to be entered to set the temperature of the condenser - varying the condenser heat duty to achieve the temperature. A total condenser is assumed. _______________________________________________________________________ T-EST Temperature estimates must be entered for the top two stages and the bottom stage (At least one temperature estimate is required). stage - Stage number from the top temp - Estimated stage temperature
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EFRACH (Continued) _______________________________________________________________________ V-EST A vapor flow rate estimate is required for the distillate rate stage - Stage number from the top mole-flow - Estimated vapor rate from the stage
L-EST A liquid flow rate estimate may be entered for the reflux rate stage - Stage number from the top mole-flow - Estimated liquid rate from the stage
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EFRACH (Continued) _______________________________________________________________________ VARY Vary may be used in conjunction with the SPEC record to achieve some design specification. By default, all exchanger duties, feed rates, and side draw rates are fixed at the user specified values. varyno - Manipulated variable number vartype - Manipulated variable type DUTY - External heat duty on a stage (requires STAGE) Q1 - Condenser duty QN - Reboiler duty FEED-FLOW - Feed rate to the column (requires STAGE) MOLE-LPROD - Flow rate of a liquid product (req STAGE) MOLE-VPROD - Flow rate of a vapor product (req STAGE) STAGE - Stage number of duty, feed-flow, or product stream _______________________________________________________________________ SPEC May be used to enter design specification. One SPEC sentence is required for each VARY sentence. specno - Spec number TEMP - Temperature on a given stage (Req STAGE) MOLE-FLOW - Total flow rate or flow rate of a group of components MASS-FLOW from a stage (Req STAGE and PHASE, COMPS requied for a group of components) MOLE-FRAC - Composition of a group of components from a stage MASS-FRAC (Req STAGE, PHASE, and COMPS) only molecular species may be selected. STAGE - Stage number from top for spec PHASE - Phase for spec V - for vapor, L - for liquid COMPS - List of molecular component IDs value - Desired value for the design specification ________________________________________________________________________ EFRACH (Continued) _______________________________________________________________________ PUMP-AROUNDS May be used to specify liquid pump-arounds in the column. Pump-arounds must be from a lower stage to a higher stage in the column. Multiple pump-arounds can not cross one another. FROM - Specifies the stage to pump from. TO - Specifies the stage to pump to.
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stage - Stage number from top MOLE-FLOW - Molar flow rate of the pump-around.
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EFRACH Example _______________________________________________________________________ Example 1 A 35 stage steam stripper with condenser. Steam feed to the bottom stage and an organic stream to stage 26.
Set stage efficiency to .5 on all stages except condenser. Spec the methanol in the bottoms product to 1 ppm by varying the steam feed flow rate.
Example 2 A 10 stage distillation column with condenser and reboiler. Feed to stage 5. Condenser is sub-cooled to 100
F and has a reflux ratio=2 (reflux rate/distillate rate). Column has a 100 mole/hr pump-around from stage 8 to stage 2. A liquid side-draw is taken from stage 3. Both
