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Problem Statement: What does the high performance pigging model do? | Solution: In the hydraulics block / pigging options, there are four type of models. One of them is called High performance pigging model.
When the high performance pigging model is selected, the pig velocity is calculated as the volume average of the liquid and vapour velocities.
Keywords: pigging, high performance, model
References: None |
Problem Statement: How do I specify the cut and orientation for support baffles in a X shell? Why is this not available in Aspen Shell & Tube Exchanger? | Solution: The X Shell is defined by the TEMA standard as a pure shell-side cross flow without cross baffles, so the only baffles that should be available for this design are support plates.
Support baffles in a X Shell (parallel flow orientation) are not going to affect significantly heat transfer/pressure drop calculations, so this is the reason why further configuration details, such as the cut, are not available in Aspen Shell & Tube Exchanger.
However, you can specify those details in Aspen Shell&Tube Mechanical. To do this you can go to the Tubes/Baffles input form, and specify the baffles as single segmental with the desired cut:
Keywords: EDR, X shell, baffles cut.
References: None |
Problem Statement: This knowledge base article outlines different operations that are required to be completed within the Aspen Reporting Framework GUI when a new set of data is published from any specific application. | Solution: If a new set of data is published from any specific application with the topic name similar to the one that was listed under the 'EIF subscription list' in the Configure Operations tab within Aspen Reporting Framework GUI, Aspen Reporting Framework identifies it as a new message. Once Aspen Reporting Framework determines that it has received a new message to be processed an informational message will be written to the log files that says ?New input message received in queue?.
Aspen Reporting Framework does not process these new messages that were in the queue automatically unless the user has configured a schedule for the three operations (Sync Data Now, Process Data Now and, Process Cube Now) under the Schedule Operations tab in Aspen Reporting Framework GUI. If there are no schedules attached to each of these operations user have to execute each step manually one after the other in the same order as arranged in Aspen Reporting Framework GUI.
In order to see more detail on how to schedule these operations please refer to knowledge base article 127812.
The different processes that occur in the background behind each of the operations are:
Sync Data Now:
Clicking on this makes the Aspen Reporting Framework to synchronize the unprocessed data that was received with the Master data entities in Aspen Operation Domain Model (ODM). The documents are processed to extract the data and then data gets loaded into the Data Warehouse.
Process Data Now:
This operation allows the Aspen Reporting Framework to retrieve unprocessed records from the Data Warehouse. The records are processed and the data is transformed. Data from the records are loaded into the Data Mart.
Process Cube Now:
Unprocessed records are retrieved from the Data Marts. The records are processed and the data is transformed into a required format. Data from the records are loaded into the Cube and ready to be visualized from the cube within BIDS.
In order to successfully update the new data that was received/Published into Aspen Reporting Framework database and to view in OLAP cube the above three operations have to be completed successfully without any errors.
Important: After each and every operation was executed make sure to check for any of the errors that are encountered while these processes are running under the Server Logs tab within Aspen Reporting Framework GUI (Make sure to hit the Refresh button to view the most recent messages).
Keywords: Publish
Schedule Operations
Aspen Reporting Framework
References: None |
Problem Statement: When I run an EO optimization run with a Custom EO Optimization objective function, I get errors similar to the following:
->Starting EO Synchronization ...
!! A+ EO parse error while processing the following line:
SYMBOLIC OBJECTIVE PROF2 = C2S.BLK.DISTILLATE_MASS * 0.4 {$/KG} * 0.0 + C2S.B L
K.BOTTOMS_MASS * 0.1 {$/KG} * 1.0 + C2S.BLK.BOTTOMS_MASS * 0.1 {$/KG} * 1.0 + C
2S.QHOT.STR.HEAT * -450 {$/MMKCAL} * 1.0 + CIN.BLK.MASS * -0.05 {$/KG} * 1.0
!! Trying to continue with remaining lines...
All measurements are correctly specified.
All connections are active.
->Finished EO Synchronization ... | Solution: The syntax for the custom objective function text is free format in that it can contain any number of spaces and new lines to make the text more readable.
However, the variable names must not cross over from one line to another. The name has to be continuous. Also note that there is a limit of 64 characters for each line of the custom objective function.
There is no continuation marker as in Visual Basic, Fortran etc. You only need to enter a return at the end of the line.
For example the following is incorrect:
C2S.BLK.DISTILLATE_MASS * 0.4 {$/kg} * 0.0 + C2S.B
LK.BOTTOMS_MASS * 0.1 {$/kg} * 1.0 + C2S.BLK.BO
TTOMS_MASS * 0.1 {$/kg} * 1.0 +C2S.QHOT.STR.HEA
T * -450 {$/mmkcal} * 1.0 + CIN.BLK.MASS * -0.05 {$/kg
} * 1.0
This expression could be written as follows:
C2S.BLK.DISTILLATE_MASS * 0.4 {$/kg} * 0.0 +
C2S.BLK.BOTTOMS_MASS * 0.1 {$/kg} * 1.0 +
C2S.BLK.BOTTOMS_MASS * 0.1 {$/kg} * 1.0 +
C2S.QHOT.STR.HEAT * -450 {$/mmkcal} * 1.0 +
CIN.BLK.MASS * -0.05 {$/kg} * 1.0
Keywords: equation oriented
optimisation
References: None |
Problem Statement: How to achieve the required tube layout using Aspen Shell & Tube Exchanger? | Solution: Aspen Shell&Tube provides a range of inputs to let you get the tube layout you want. It will provide defaults for all the inputs, but if the layout generated with defaults does not meet your requirements, then you can modify the various inputs as required.
Inputs affecting the tube layout include the following:
Number of passes
Pass Layout: Single banded, H-banded, or Double banded (quadrant)
Pass Layout orientation: Standard (horizontal) or Vertical ? determines primary PP lane orientation
Tube Pitch and Tube Pattern ? determine spacing of tube rows and columns
Pass partition (PP) lane widths ? horizontal and/or vertical
U-bend orientation ? horizontal or vertical
U-bend minimum diameter ? affects PP lane width
Cleaning lane or tube alignment ? affects PP lane widths
Remove tubes below nozzle ? none, normal, in nozzle projection (for each nozzle)
Tube Layout Design ? Full or normal bundle ? determines default for tubes removed under nozzles
Shell bundle clearance / Outer tube limit diameter : one or the other
Open distances on top / bottom / left / right of bundle: If specified exactly, these will override specification of tube removed under nozzles.
Tube Layout Symmetry ? Standard, Full, or not enforced ? sets odd or even number of rows or columns, to adjust open distances at sides, and ensure a central row/column of tubes when appropriate.
Replace tubes by Tie rods (if necessary): can make small changes to number of tubes.
The above apply to the New Layout option in performance modes. They are mostly also available in Design mode, exceptions being number of passes and explicit specification of clearances and open distances, which depend on exchanger size.
When using Specify Pass Details, the above inputs for clearances, open distances, and PP lane widths are used directly. Other items above are used to set default values for these inputs.
You do not have to get a layout exactly right before doing calculations on an exchanger. You can explicitly specify the number of tubes to be used in the thermal and hydraulic calculations. Differences in detail between your exchanger and the layout the program generates often have only a small effect on calculated performance. Whenever the layout predicts a different number of tubes from what you specify, a warning is produced.
Keywords: tube layout, customize, required layout, matching
References: None |
Problem Statement: How do I add tube supports to deresonating baffles? | Solution: Deresonating baffles are parallel to tubes (perpendicular to the baffles) in a heat exchanger. However, they are narrow (or not wide enough) to block the shell side flow.
Tube support option is available for NTIW or cross flow type shell. The fields for specifying the number of supports under Exchanger Geometry || Baffles/Supports || Tube Supports tab will be active only when suitable configuration or shell is chosen.
Keywords: Tube support, baffles, deresonating
References: None |
Problem Statement: What are the Solver Control options in the Aspen Hydraulics Dynamics for? | Solution: Options Common to All Dynamic Solvers
Maximum Auto Recovery Attempts
Solver internal snapshot control (*)
Auto Recovery Decrease Factor
Solver internal snapshot control (*)
Auto Recovery Increase Factor
Solver internal snapshot control (*)
Auto Recovery Snapshot Interval
Solver internal snapshot control (*)
Automatic Recovery Increase Period
Solver internal snapshot control (*)
Outer Loop Tolerance
Determines outer iteration convergence tolerance
Max Outer Loop Iterations
Determines maximum number attempts at convergence
Interfacial/Vapour Friction Factor Ratio
This option allows you to specify a two-phase friction factor in order to model pressure drop data.
Phase Change Relaxation Factor
This term limits the rate of a transient phase change. This method allows the simulation of blow down.
Maximum Liquid Holdup
Limits maximum liquid holdup predicted during phase change
Heat Transfer
Selects the amount of energy balance equations in use.
OFF: Turns Energy balance off, the Temperature profile will depend on the initialization technique (either SS profile or flat temperature)
No interfacial: Two energy balances (for the Gas and Liquid phases) with no heat flow between the two phases
Discrete Phase: As before but with a high heat transfer rate between the gas and liquid phase
Combined phase: one Energy balance for both phases.
Dissipation During Heat Transfer
Enables the dissipation term of the energy balance
Cool Down
Switches off momentum balance and just performs energy balance
Choke Flow
Off: No Choke flow prediction is performed
Homogeneous Frozen: Assumed the flow is homogeneous at the choke plane and the gas flow is equal to liquid flow (no Slip Velocity).
Homogeneous Frozen Split: same as above but it allows a slip velocity between the phases while the mass flux approaches the critical one.
Homogeneous Equilibrium: The composition on the choke plane is assumed to be in equilibrium and with zero Slip velocity.
Phase Change
Convective: Interface mass transfer due to Change in pressure and temperature along the pipe
Transient: Mass transfer due to change of temperature and pressure respect to time.
Convective And Transient: Includes both Convective and Transient terms
Inhibited: Turns off mass transfer calculations
Wall Friction
It includes several options depending on the scenario you are modelling.
Refer to the Aspen Hydraulics Dynamics
Keywords: Relaxation Factor, Choke Flow, Auto Recovery, Aspen Hydraulics
References: Guide for more details ( |
Problem Statement: How do I save an Exchanger Design and Rating plot as an image file? | Solution: The Plots are available under Analysis along Shell (or Tubes) under Results | Calculation details. Then you need to go to the Plots Tab and click on the Tools button.
Then you need to clock on the option to Save plot to file.
The default is XML. However if you save the file as a Metafile or as an Enhanced Metafile you should be able to open the plot.
Keywords: Plot, save, image, open
References: None |
Problem Statement: CLP failed to turn ON with the message Storage allocation failure in clpmain: program exiting in the CLP error log file. | Solution: This issue is typically caused if the value of IZCDEN (Model Density) is too large (closer to 100). IZCDEN refers to the density of the models that make up the final CLP problem. A value of 100 for this parameter indicates the presence of a fully dense model matrix, in other words it indicates to the CLP engine that there would be a model curve between each Independent (IZCLPD) and Dependent (IZCLPI) pair in the final merged CLP model. The CLP engine uses the information in IZCDEN to estimate the amount of memory/storage to be allocated to handle the problem.
Larger the value of IZCDEN, larger is the amount of storage necessary. If the size of the individual controllers participating in the CLPSolution is large and the IZCDEN is set to 100, the final storage that CLP requires to allocate for the problem exceed the maximum limit built in the program, thus leading to the storage allocation error.
A typical CLP problem would not have a highly dense model matrix. The value of IZCDEN for such typical CLP problems is around 30 (model density = 30%). An appropriate value for IZCDEN should be estimated based on the mappings involved from the individual controllers to the CLP.
Keywords: Storage allocation failure
Composite
IZCDEN
References: None |
Problem Statement: Exchanger Design and Rating (EDR) has a number of supplied templates that can be used to transfer data from the programs to Excel, where there are TEMA or API datasheets supplied for example.
Users can use “Blank” templates to create their own customized templates to transfer data between EDR and Excel. Sample templates are normally located in the folder “C:\Program Files(x86)\AspenTech\Aspen Exchanger Design and Rating Vx.x\Excel Templates” where the path can vary depending on the installation folder and program version. | Solution: Steps to create an Excel template with EDR are given in the attached pdf, that shows how to use a “blank” template to drag and drop input/results data between programs.Solution #126476 “How to change the default Excel template when exporting the EDR results to an Excel template?” explains how a default template location can be set inside the programs and then how to export results to the Excel file.
In addition, Aspen Simulation Workbook (ASW) http://www.aspentech.com/products/aspen-simulation-workbook.aspx may be used to run EDR from Excel. From the AspenTech Support website there are Product Video Tutorials available explaining how to use ASW, such asSolution #130667 “Exploring multiple operating scenarios using Aspen Simulation Workbook and Aspen Shell & Tube Exchanger”.
Keywords: Customizing templates, linking Excel, creating templates
References: None |
Problem Statement: Two-phase flows can be susceptible to instabilities which is often an important parameter in the design of thermosiphons. | Solution: Excursive instability occurs when a slight perturbation causes a dramatic and permanent change in flow and might also induce a temperature excursion. This type of instability is often referred to as “Ledinegg” instability and can result from improper matching of the pump to system characteristics. When a fluid is boiled in a single tube with constant heat input, the pressure drop may be measured as a function of flow rate as shown in the Figure a below.
At high flow rates, little boiling occurs and the pressure drop is characteristic of single phase (CD). As the flow rate is reduced, boiling occurs and as the increase in the two-phase fictional pressure drop is much greater than the decrease of the single phase liquid, the pressure drop increases (CB). Eventually at low flow, the tube is full of superheated vapour and the pressure drop is once again that of single phase (AB). Superimposing a pump characteristic curve (EFG) it can be seen that operating at point F, the system may be unstable as any changes in pressure drop may result in a shift to the new operating points E or G. Pressure drop characteristics of this type will always exhibit instability and must be accounted for in the plant design. The addition of an inlet restriction, before the tube, is shown in Figure b, for line B, where the flow will be single phase so increases with flow rate. Line C shows the inlet restriction and heated channel pressure drops added together, where now there is only one intersection of the pump curve so the flowrate will be stable. However, it is necessary to ensure that there is a reasonable relative slope between the two curves to ensure a pressure oscillation leads to a small oscillation in flow rate.
To minimize excursive instabilities, then often the pressure loss at the inlet to the boiling section, is increased by the introduction of a throttle valve for example.
Keywords: Ledinegg, Flow Instability, Excursive
References: None |
Problem Statement: Two-phase flows can be susceptible to instabilities which is often an important parameter in the design. Probably, the most important is oscillatory instability. | Solution: Oscillatory (or Density wave ) instability can be important because of feed-back effects due to time lags in the system. If it is assumed that the inlet flow is oscillated at a low frequency, then the components of the pressure drop (friction, gravity and momentum) are in phase so the pressure drops are additive. However, as the frequency increases lags can occur between the various pressure drop components, so there is no variation in the pressure drop.
The following steps can be taken to minimize oscillatory instability;
· Introduce a flow restriction in the single phase inlet piping region ( B above)
· Minimize outlet restrictions after the heated channel. Reductions in the cross-sectional area at outlet, valves and other forms of outlet restrictions (e.g., sharp bends) should be avoided (reduce C above).
Keywords: Oscillatory, density wave, flow instability
References: None |
Problem Statement: For weighted feedstock blend in Olefins regression calculator, what signifies a stronger weighting or a lesser weighting? | Solution: For the weightings, a higher value indicates a stronger weighting whereas a lower value indicates lesser weightings. This is not explicitly specified in Help documentation but can be used in Olefins Regression calculator.
Keywords: Olefins regression calculator
Feedstock blend weightings
References: None |
Problem Statement: After successfully running an Aspen EDR (Exchanger Design and Rating) case, users can go to the top menu of the program File | Print tab, where they can set which section(s) of the results will be printed and corresponding ''Print Settings'', including page number, file name, date, time, headings etc. However, these do not include Company Logo. How could Company Logo be set for printing? | Solution: To set your own company logo, please follow the below steps.
1. To set the Company Logo, from the top of the program menu, go to Tools | Program Settings | Headings/Drawing tab, where you will see Company Logo section.
2. Click the ''Browser'' button, and navigate to the directory where your logo picture file is located and point to the file. Please be aware that it must be a Windows metafile (*.WMF) file.
3. Click ''OK''.
Now when printing the results, you should see your Company Logo on the top (page head) of the paper.
Keywords: Company Logo, Print setting, Page head, *.WMF file.
References: None |
Problem Statement: I have an inhouse databank that I can use in EDR V7.3.2 but when I upgraded to EDR V8.4 + Aspen Plus V8.6, I can see the custom databank in the database manager, in Aspen Properties/Plus, but cannot see the custom databank in EDR. | Solution: APED always delivers six sample files that can be used to create custom database. These files were tested and no changes have been made since APED started. The below is listed of these files delivered with APED V7.3:
These files cover pure parameters, binary parameters, pair parameters and equilibrium constants. Specifically, the parameters covered are as follows:
1. dfms_pure1.inp and dfms_pure2.inp contains pure parameters.
2. dfms_binary.inp contains Henry’s constants.
3. mmtbs_sample.dat contains NRTL parameter.
4. elec-sample.dat contains electrolyte pair parameters.
5. reactns-simple.dat contains equilibrium constants.
Users can create a custom database (called as USERDB1) using the Database Manager by importing these sample files:
The databanks from the custom database can be used directly in Aspen Plus as shown below:
Follow the above general procedure to use the custom database in Aspen Plus and EDR.
Keywords: None
References: None |
Problem Statement: I've added a new crude from the Aspen Assay Manager (AAM) library in the weight sample model but the yields don't add up to 100%. | Solution: AAM imported some historic data about cut points from PIMS Assays table which were incorrect and thus caused wrong calculations. FVT data in the weight sample model had no use before advent of Aspen Assay Manager and carried on some incorrect figures for years.
The AAM set-up automatically finds and reads FVT data from the PIMS Assays tables during initial set-up and it is critical to verify that these are indeed correct or reasonable as they will later play a critical role in calculations.
The screenshot below highlights the incorrect data visible during set-up process:
The temperature needs to be continuous for material balance. AR1 should be 670-FVT instead of 1050-1832 and VR1 should be 1050 - FVT instead of 1832 - FVT.
Keywords: Weight balance
Crude
Assay
Library
References: None |
Problem Statement: Why does Exchanger Design and Rating (EDR) calculate an overallEffective MTD that is greater than the LMTD? | Solution: The Effective MTD is one type of mean temperature difference of all temperatures points that have been rigorously calculated in the EDR based on point-by-point integration. On the other hand, LMTD is only based on the end-point temperatures, and is the way to report the effective temperature difference in an exchanger with constant heat transfer coefficient, constant gradient of enthalpy versus temperature, and a pure counter flow (single pass), as seen below.
The effective MTD correction factor is the ratio of the effective MTD and the LMTD, and we report it since it can be useful for comparing a design with pure counter-current flow. This factor is only valid for comparison of linear heat curves. If the heat curves are not linear, as illustrated in the figure below, then the effective MTD correction factor is not valid, and should be ignored.
Keywords: Effective MTD, LMTD, Correction Factor
References: None |
Problem Statement: Why doesn't the vapour fraction in Exchanger Design & Rating (EDR) property slates correspond to Aspen HYSYS? | Solution: EDR can be linked with exchangers in the process simulation using Aspen HYSYS for rigorous heat transfer calculations. The property slates in EDR are generated from the properties in the simulation with fixed pressures and temperatures. EDR interpolates the properties from the property slates when performing the thermal calculations.
Users should note that the vapour fraction in EDR is based on mass fraction. Aspen HYSYS reports vapour fraction in the condition page as mole fraction.
In Aspen HYSYS the vapour mass fraction is reported in the Properties page as shown below.
To compare the vapour fraction between EDR and HYSYS, the user should refer this properties page where the vapour fraction is reported on mass basis.
Keywords: Property Slates, Vapour Fraction
References: None |
Problem Statement: For many medium pressure compressor intercooler applications, radial fins are being applied on the shell side of shell & tube exchangers. It is now possible in Aspen Shell and Tube Exchanger, since V8.0 to model X-shells with special finned tube bundles including tube in plate and a range of other high fin types. | Solution: The shell type for the heat exchanger must first be set to an X shell that can be set from Input > Exchanger Geometry > Geometry Summary > Geometry tab
Alternatively it can be set from Input > Exchanger Geometry > Shell/Head/Flanges/Tubesheets > Shell/Heads tab
Now from the Input > Exchanger Geometry > Tubes > Tubes tab, for the Tube type, “Other (radial fins) can be selected.
From the Fins tab, the type of radial fin and geometry can be entered.
If the above form has all the input items ”greyed out”, then the shell type has not been set to an X shell and also from the Input > Exchanger Geometry > Tubes > Tubes tab the Tube type input will have a red background indicating that the input select is not acceptable. If the case is run an Input Error 1124 is given that “The data input for Tube type is unacceptable”.
Keywords: Radial fins, input error 1124
References: None |
Problem Statement: What is the approach used in Assay Management to characterize a contaminant? | Solution: For contaminants like Mercury, Nickel, Iron, Vanadium, etc., they are treated as metal contaminants. The distribution is a probability curve. Even if the user provides input data for these metal contaminants, they are overwritten and estimated using a probability curve like below.
Currently there is no other correlation to estimate mercury distribution in Assay Management. However, if a user has experimental data for mercury distribution, then Assay Management can spline fit them as a user-defined property. Note that there should be a minimum of 3 non-overlapping cuts' input defined by the user for mercury contaminants.
1. In Library | Property library, add a new property for Mercury contaminant, select “User-defined” in the Group, and select “Calculated using curve fit to user input data”
2. User provides at least 3 inputs for mercury contaminants (HG%)
3. Characterize the assay and you will get mercury distribution estimated based on the input data (instead of a probability curve)
Keywords: Contaminant
Mercury
Characterization
Probability curve
Spline fit (polynomial interpolation)
References: None |
Problem Statement: Apache Tomcat Manager service fails to start on the aspenONE Process Explorer server with the following errors in the Windows Event logs
The apache tomcat service terminated with service-specific error incorrect function
Simultaneously, the Tomcat logs located in <Tomcat>\Logs folder report the following error:
Failed creating java jvm.dll
This article provides a | Solution: on how to address this errorSolution
This error occurs when 64 bit version of Java is configured to be used by the default 32 bit installation of Apache Tomcat Manager.
In order to fix this error, Apache Tomcat Manager Service needs to be configured to use the 32 bit version of Java.
1. Open Tomcat7w.exe located in C:\Program Files (X86)\CommonFiles\AspenTech Shared\Tomcat7.0.57\bin
2. Click on JAVA
3. Change the “Java Virtual Machine” to use the 32 bit version of jvm.dll located in “C:\Program Files(X86)\Java\Jdk1.7.0_51\bin\client\jvm.dll”
4. Next change the JAVA_HOME environment variable to use the 32 bit version as well.
Set this to “C:\Program Files(X86)\Java\Jdk1.7.0_51”
Now try restarting the Apache Tomcat Manager Service
Note: The 32 bit version needs to be available on the system. The 32 bit version of Java Development Kit (JDK) and Java Runtime Environment (JRE) can be downloaded from the Oracle website.
Keywords: Tomcat
JVM
A1PE
References: None |
Problem Statement: How can I copy a feed composition from Aspen Olefins Regression Calculator (AORC) to Aspen Olefins Scheduler (AOS)? | Solution: New feedstock composition to AOS can be obtained from AORC for those that do not have lab analysis data. ThisSolution is demonstrated using the demo Olefins database
1. Open the demo Olefins database
2. Login as ADMIN (no password).
3. Switch to any events screen and select Model | Feedstock from the main menu.
4. Click New button to add a new feedstock, if there is no lab analysis data available for this feedstock, then click Add Analysis to import from AORC. After clicking Add Analysis button, enter a time within the model horizon
5. Select OK when finished
6. Select the Import button
7. Select Yes to import data; a dialog containing Feedstocks defined in the AORC will be displayed.
8. Select a feedstock, for example, Australia75 and press OK
Data will be populated into the grids.
Keywords: Aspen Olefins Regression Calculator
AORC
Copy feed composition
References: None |
Problem Statement: How do I include hydrostatic head (gravity) for a vertical exchanger? | Solution: Select friction+gravity for the pressure change parameter n the Input\Program options\Thermal Analysis. See in the screenshot given below.
The exchanger orientation can be selected from Input/Exchanger Geometry/Geometry Summary as highlighted below.
The calculated results can be found in Results\Result Summary/Overall Summary as shown below.
Keywords: Hydrostatic Head, vertical shell & tube exchanger
References: None |
Problem Statement: When I use the “add new case� window in Aspen Olefins Scheduler, enter the details for the case, and click OK, I get this error message (“Failure in executing SQL INSERT INTO AtOrionMaterialPriceDetails ….� | Solution: When a new case is created, the case specific tables in the database are duplicated as new entries, under this new case name. One such table that is case specific is ATOrionMaterialPriceDetails. Also, one of the fields in the ATOrionMaterialPriceDetails table is “START� and the error message above is brought about by invalid dates in this field. As by the current design, dates earlier than 01/01/1970 are invalid. The customer should check for whether this table has any ‘invalid’ dates before this period, while adding a new case.
Keywords: ATOrionMaterialPriceDetails, Add New Case, Aspen Olefins Scheduler
References: None |
Problem Statement: How to resolve “Access Denied” error while using Edit in Excel option for an event in Aspen Olefins Scheduler? | Solution: This error is received when there is an access issue with the folder where the file dsn is stored,
In this case, the file dsn is stored in C: Drive in a folder where the user does not have proper access.
To resolve this issue, please follow below steps:
1. Copy the file dsn to My Documents or a different drive than C: drive to which user has proper access.
2. Close the model and reopen the model with dsn present in this new path (here -i.e. My Documents).
3. Now, in the model, select the event and Right click >Edit in Excel
It should now successfully work without a pop up message being displayed.
The same can also be tested and confirmed using Multiple Event Editor.
Keywords: Olefins Scheduler, Access denied, Edit in Excel
References: None |
Problem Statement: If BJAC database is modified then what files are modified and where is their location? | Solution: If you save a User databank, the following files:
D_FXPRIV.PDA
D_IDPRIV.PDA
D_VAPRIV.PDA
are written to the following folder:
C:\ProgramData\AspenTech\Aspen Exchanger Design and Rating
(note that you may have to change the folder option setting in Windows, to view the hidden files)
And if you save the B-JAC databank the following files:
D_FXBJAC.PDA
D_VABJAC.PDA
are written to the EDR installation in:
D:\Program Files (x86)\AspenTech (x86)\Aspen Exchanger Design and Rating V8.0\Dat\PDA.
Keywords: BJAC, databank files, save
References: None |
Problem Statement: How can I change the Aspen Exchanger Design & Rating (EDR) calculated Heat Transfer Coefficients and provide my own values? | Solution: EDR calculates the HTC from different correlations. However, there may be cases where you want to force the program to use a specific coefficient. Or you may want to use a multiplier for the heat transfer coefficient calculated by the program. To do this, go to Input | Program Options | Thermal Analysis and input the values in this form:
If you specify a value for the coefficient, this value will be used for the calculations.
If you specify a multiplier, the calculated coefficient will be multiplied by this value and this value will be used for the calculations.
Keywords: factor, htc, heat transfer coefficient, EDR
References: None |
Problem Statement: Aspen Shell & Tube Exchanger (Shell&Tube) Warnings & Messages | Solution: Aspen Shell & Tube Exchanger provides an extensive system of errors, warnings and other messages to help you use the program. They are for the most part self explanatory, and contain information on the values of parameters which have led to the reported condition. There are several hundred messages built into the program, and these can be divided into number of types.
Range Checking Warning.
These relate to input values which are outside the range of what is normally expected. You should check that the input value referred to is correct. If so the message can usually be ignored, though for unusual exchanger geometries, or unusual fluid properties, it is likely that the uncertainty in the results is exacerbated.
Input Omission Error
These identify input parameters which are necessary for the program to run. Whether a particular parameter is necessary can depend on the values of other parameters. Required input is normally identified in the User interface, though there are occasionally instances where a required item is not highlighted in the Interface, or where an item is shown as required by the interface, does not lead to an error when the program is run.
Range Checking Error
These identify input values which are beyond the range of what is permitted. They cause program execution to cease.
Results Warning
The run has completed, but problems have been identified with some part of the calculation, which indicate that some aspect of the results may be subject to more uncertainty than normal.
Results Error
The run has either failed to generate a significant part of the results, or failed to complete in some way that many of the results given should not be relied on.
Operation Warning
The run has completed, but is predicting operation which does not meet normal practice, or is in some other way inadvisable, or in extreme cases impracticable.
Advisory
There is some feature of the exchanger, or its operation which is unusual, and for which better alternatives may exist.
Notes
Any other information which may be useful.
Keywords: warning, error, message
References: None |
Problem Statement: In Aspen Shell & Tube Exchanger (Tasc+), users have three options to select, determining which tube layout information the thermal calculations will be based on. These options are: 'Use existing layout' with tube layout data as basis; 'New (optimum) layout' based on tube layout input items; 'New layout to match tubecount' sticking to the input number of tubes. The usages of them are described in | Solution: 125797.
In some circumstances the above options may cause inconsistencies between the tube layout and the main input values, when the case is subsequently run. This especially may occur when you make substantial modifications to the tube layout, for example by changing the relative locations of various passes. You can determine if the program will use data from the main inputs or tube layout in terms of thermal calculations with a relevant warning generated, or treat the inconsistency as a fatal error.Solution
On Input | Exchanger Geometry | Bundle layout | layout Parameters tab, users can decide how the program will treat 'Main input / Tube layout inconsistencies'. See the screen shot below.
This item indicates how Shell & Tube Exchanger (Tasc+) should treat any conflicts that arise between items in the Main Input and the Tube Bundle Layout. It is needed when some inconsistency has been introduced between the Layout and Main Input, generally by editing one or the other.
In case of having main input / tube layout inconsistencies, you need to indicate whether, if the inconsistency cannot be reconciled, the value from the Main Input, or the Tube Layout should be used in subsequent Thermal calculations. There are three options you can select under this item:
1) Treat as Fatal Error
Any discrepancy between the Tube Layout data and Main Input generates a fatal error, so that Shell & Tube Exchanger (Tasc+) will not run to completion until you have addressed the issue. For special circumstances, however, there are facilities that let you treat them as Warnings.
Your Tube Layout and Main Inputs are unchanged until you modify one or both. Deleting the main input, to pick up the value from the Layout, is the simplest way to do this, provided the Layout value is acceptable. You will see the value from the Tube Layout, and can check that it is acceptable
Use Layout value (warning)
This option will cause Shell & Tube Exchanger (Tasc+) to use the value(s) from the Layout, and ignore any inconsistent value in the Main input. Warning messages will be produced.
2) Use main input value (warning)
This option will cause Shell & Tube Exchanger (Tasc+) to use the value(s) from the Main Input, if possible, to update the Layout, so that the two are consistent. Sometimes it is not possible to update the Layout based on the main input values, then a warning message will be generated, but the value from the Main input will still be used in the thermal calculation.
It is important to remember that this item only deals with inconsistencies between the Main Input and the Tube Layout Diagram. It does not deal with inconsistencies or physical impossibilities within the diagram itself. The diagram does a certain amount of checking, but does not, for example, do complete cross checking to ensure that no items clash, i.e. seal strips over a tube, impingement plates over a tie rod, etc. You need to look at the diagram after editing to check that it is physically sensible.
Keywords: Inconsistency, Tube Layout, Layout Value, Main Input, Existing Layout, Fatal Error
References: None |
Problem Statement: Can I create an Ad-Hoc SPC plot for an Aspen Production Record Manager characteristic in aspenONE Process Explorer? | Solution: While you can create an Ad-Hoc SPC plot for any tag stored in Aspen InfoPlus.21, you cannot create Ad-Hoc SPC plots for Aspen Production Record Manager characteristics.
Keywords: APRM characteristics
Ad-Hoc SPC
References: None |
Problem Statement: When using the search boxes while adding tags to plots in aspenONE Process Explorer, you may receive the message
Search error: make sure search server is properly configured in AtWebPlotsConfig.xml and search server (tomcat 7) is running. Also, make sure the login user is in the solr security domain.
The article describes how to correct this error so that search boxes work correctly. | Solution: If the Aspen InfoPlus.21 / aspenONE Process Explorer system is running in a workgroup, Tomcat security (SOLR Domain Security), which is enabled by default, is not needed and must be turned off.
Navigate to this file and modify it using Windows Notepad:
C:\Program Files (x86)\Common Files\AspenTech Shared\Tomcat7.0.57\appdata\solr\conf\solrconfig.xml
There is a section which has the following:
<!-- The SECURITY COMPONENT! -->
<searchComponent name=security class=com.aspentech.solr.security.AddSolrSecurity>
<str name=enabled>true</str>
<lst name=domainInfo>
<str name=domain>MYDOMAIN1</str>
In that section there is a value of true - see highlighted line above. Change that value to false so it looks like this:
<!-- The SECURITY COMPONENT! -->
<searchComponent name=security class=com.aspentech.solr.security.AddSolrSecurity>
<str name=enabled>false</str>
<lst name=domainInfo>
<str name=domain>MYDOMAIN1</str>
Then save the file and restart the 'Apache Tomcat 7.0 Tomcat7' service. Close any web browsers and try the aspenONE Process Explorer search again.
Keywords:
References: None |
Problem Statement: In some applications such as environmental or nuclear applications, very small amounts of a component are relevant and important. The flash Aspen Plus ignores components with a flow of less than 1e-15. The flow of these components is then set to zero. Do we have control over the value of trace threshold within a simulation? It cannot be found in the Setup\Simulation Options form.
Is it possible to allow calculations for components with mole fractions less than 1e-16? | Solution: The trace threshhold values for a component are stored in the DMS_RGLOB common as RGLOB_RMIN (mole flow minimum) and RGLOB_XMIN (mole fraction minimum). In version 2006.5, these variables are accessible on the Setup | Simulation Options | Limits sheet as Minimum Flow (RGLOB_RMIN) and Minimum Fraction (RGLOB_XMIN). In version 2006 and earlier, the values need to be accessed and modified using Fortran in a Calculator block.
A component is included in the calculation if
1. The mole fraction of that component is at least RGLOB_XMIN (default of 1D-15) in a stream with a mole flow at least RGLOB_RMIN (default of 1D-15).
2. The component can be created due to reaction.
An example file is attached where RGLOB_RMIN and RGLOB_XMIN are set to lower values in a Calculator block using the following code:
CALCULATOR TRACE
F #include dms_rglob.cmn
c If the quotes are omitted in the statement above,
c the file will appear to run, but the modified values
c for RMIN and XMIN will not be used.
DEFINE IN MOLE-FLOW STREAM=FEED SUBSTREAM=MIXED &
COMPONENT=TRACE
DEFINE OUT2 MOLE-FLOW STREAM=TOP2 SUBSTREAM=MIXED &
COMPONENT=TRACE
DEFINE OUTBOT MOLE-FLOW STREAM=BOTTOM2 SUBSTREAM=MIXED &
COMPONENT=TRACE
F RGLOB_XMIN=1e-30
F RGLOB_RMIN=1e-30
EXECUTE FIRST
Note: A Fortran compiler is needed to run this example.
Keywords: None
References: None |
Problem Statement: What is the Aspen Properties Enterprise Databank (APED) and how do I get it? | Solution: The Aspen Properties Enterprise Database is the new relational properties database used with Aspen Plus and Aspen Properties 2006. This database is an option in 2006, but will become the default in V7. For 2006 and 2006.5, it was thought that it was better to keep the legacy databanks as the default to avoid potential installation issues.
To switch to the Aspen Properties Enterprise Database, go to the Windows Start menu and select Programs | AspenTech | Aspen Engineering Suite | <product> | Aspen Properties Database Selection Application. Select Aspen Properties Enterprise Database and click OK. You can re-run this tool to switch back to the traditional databank system if needed.
Some of the advantages of the Aspen Properties Enterprise Database:
It is a relational database.
The Aspen Properties Enterprise Database used in Aspen Plus and Aspen Properties 2006 is a relational database. This database architecture is a major upgrade from the architecture used in previous versions of these products. The 2006 database was developed using the Microsoft SQL Server and .NET technology.
In 2006, by default, the Aspen Properties Enterprise Database is delivered and set up to run with MSDE (Microsoft SQL Server Desktop Engine). Optionally, you can install the database on a Microsoft SQL Server 2000, which may be a central database server that can be shared by many users within the company. In aspenONE 2006, the Aspen Properties Enterprise Database does not support the Oracle database. In 2006.5, the database switched to use SQL Express by default. This improved robustness and troubleshooting capabilities.
Additional information such as citations, uncertainty and notes were added to the existing databanks.
Aspen Plus and Aspen Properties 2006 are installed with a default property database called AP06. This database contains 30 databanks, including PURE20, PURE13, AQUEOUS, SOLIDS, INORGANIC, and VLE-LIT, and other databanks from previous versions. Users are NOT allowed to modify this database. However, you can create your own database(s) and use them in the simulation.
The NIST databank with 15,000 components is available.
The Enterprise Database comes with the NIST06 database containing the NIST-TRC databank. This database contains properties for many thousands more compounds than the traditional databank system could handle, so it is only available in the Enterprise Database.
It is much easier to add a custom databank.
When creating a user database, it is not necessary to customize the Aspen Plus and Aspen Properties simulation engine and GUI as was required in previous releases. With the new database architecture, any user database created using the Aspen Properties Database Manager will be automatically available for use in Aspen Plus and Aspen Properties.
Keywords: aped
References: None |
Problem Statement: There is no unit of measure given in Aspen Plus for the Bond Work Index used in the Crusher model. Are you using exactly the same units as in Perry's Handbook? An example file uses a Bond Work Index of 61270, which is way above the listed ones in Perry, that go from 1 to 150. Is this reasonable? | Solution: Bond work index is the work required to reduce a unit weight from a theoretical infinite size to 80% passing a diameter of 100 micrometers. Bond Work Index and Hardgrove Grindability Index do have units. The units are: J/kg for SI, kWhr/ton for ENG and MET, and an additional KJ/kg. The conversion between J/kg and KWhr/ton is 3.968321d3. That is 1 KWhr/ton = 3968.321 J/kg.
The values in table 8-1and in Perry's Chemical Engineers' Handbook, 6th edition are in KWhr/ton.
If the example is using SI units, then 61270 J/kg is about 15.4 KWhr/ton, which is reasonable.
Fixed in Version
2006 will have the units noted in the GUI.
Keywords: crusher
solids handling
mill
References: : CQ00197460 |
Problem Statement: After uninstalling the default release, file associations are lost. How can this be fixed? | Solution: If a user un-installs the default release, file associations are lost. So, if a user installs and then un-installs a release, when they double-click on (for example) a bkp file, the previous release of Aspen Plus will not start up. They can, however still start Aspen Plus from the start menu or an icon on their desktop. This problem cannot be fixed with the current architecture.
However,
1. If the user starts Aspen Plus (say from the start menu), Aspen Plus will fix the file associations. So, after the first time they run Aspen Plus, the file associations are fixed. The user needs to be an administrator for this to work.
2. For Aspen Plus 12.1 and higher, a small utility will be supplied which will fix the file associations. It will allow the user to pick which release will be the default (based on all the releases installed on the user's computer). It will also fix all other registry entries, just in case the un-install does not work completely. It will be similar to apwnsetup, but should be easier to run and will not give the user the option of breaking their Data Browser forms database.
3. To access the post-12.1 utility, go to Start Menu / All Programs / AspenTech / Aspen Engineering Suite / Aspen Plus 200x.x / Aspen Plus Registry Fix Utility. Choose the installed version you wish do associate files with.
Keywords:
References: None |
Problem Statement: Multiple application (Tasc+ now Aspen Shell& Tube, Acol+ now Aspen Aircooler, Hetran, Aerotran, Teams now Aspen Shell & Tube Mechanical, Plate+ and all HTFS+ suite of products) files can be saved under same file name with an extension *.EDR. If you have to send it to someone without license for one of the products or you do not want show another application, then How does one remove an application from that *.EDR file. | Solution: Open the *.EDR file that has multiple applications and then go to File | Remove Application. Then Select the application to be removed and click OK. Then save the file with a different name.
In versions 2006.5 and later, HTFS+ offers a dialog to select what application to be opened while opening a file that contains multiple applications saved in it.
Keywords: Remove application, Tasc+, Acol+, Teams, Hetran, Aerotran, Plate+
References: None |
Problem Statement: How do I get the new binary interaction parameters available in 11.1 SP1 for the SRK property method? | Solution: The binary interaction parameters for the SRK property method for
34 systems (listed below) involving hydrogen sulfide, carbon
dioxide, nitrogen, and hydrocarbons have been regressed from
available experimental VLE data obtained from the Dortmund
Data Bank (DDB). The updated parameters are delivered as a user
databank. In Aspen Properties 12.1, these parameters will be
available in the built-in databank.
The user databank can be found in the
APrSystem 11.1/Users/Userdatabank folder. This is a pp2a type
databank.
To use the databank:
1 Add USRPP2A to the list of Selected databanks on the
Components | Specifications | Databanks tab.
Select Settings from the Run menu in Aspen Plus (Select Settings from the Calculate menu in Aspen Properties) The Run Settings dialog box appears.
On the Engine Files tab, enter the complete path of the user databank file in the pp2a field of the User property databanks section. For example: C:\Program Files\AspenTech\APRSYSTEM 11.1\Users\UserDatabank\usrpp2a.dat
Select Retrieve Parameter Results from the Tools menu and then go to the Properties \ Results \ Binary Interaction to see the results.
New SRK Binary Interaction Parameter Pairs
H2S - 2-METHYLBUTANE
PROPANE - TOLUENE
CO2 - P-XYLENE
H2S - N-HEXANE
N-BUTANE - N-HEPTANE
CO2 - M-XYLENE
H2S - BENZENE
N-BUTANE - BENZENE
CO2 - O-XYLENE
H2S - N-HEPTANE
N-BUTANE - AMMONIA
CO2 - 1,3-BUTADIENE
H2S - TOLUENE
BENZENE - AMMONIA
CO2 - BENZENE
H2S - N-OCTANE
BENZENE - TOLUENE
CO2 - CO
H2S - N-NONANE
CO - N-OCTANE
N2 - PROPYLENE
H2S - N-BUTANE
N-HEXANE - N-OCTANE
N2 - ISO-BUTYLENE
H2S - ISO-PENTANE
CO2 - PROPYLENE
N2 - M-XYLENE
H2S - M-XYLENE
CO2 - 1-PENTENE
N2 - 1,3-BUTADIENE
ETHANE - TOLUENE
CO2 - ETHYLBENZENE
N2 - TOLUENE
PROPANE - AMMONIA
Keywords: SRKIJ
References: None |
Problem Statement: When running the Process Cube component from the Aspen Reporting Framework user interface Schedule Operations tab for the first time to view the master data in the cube within Microsoft SQL Server Business Intelligence Development Studio (BIDS) may return an error and processing may fail with the following message in the Server Logs
The dimension '[Today]' was not found in the cube when the string, [Today], was parsed | Solution: The aforementioned error may be seen in the Server logs when processing the cube for the first time to view the master data on some machines because of the conflict between the time format within the local machine where Aspen Reporting Framework is installed and the ASCII time format used in the code. For this reason the time string was not parsed correctly during the process of retrieving master data to the cube and thus giving an error. You can work around the issue by changing the time format which is hard coded in the cube within Microsoft SQL Server Business Intelligence Development Studio (BIDS).
1. First go to Settings | Control Panel | Regional and Language Options to determine the time format on the local machine.
2. After this go to Microsoft SQL Server Business Intelligence Development Studio (BIDS) ,
Open the Analysis Services Database that was created to communicate with the Aspen Reporting Framework database
Expand the Cubes from theSolution Explorer and double-click on Supply Chain cube which opens up a new tab called SupplyChain with several other tabs within.
Go to Calculations tab and then to a command [Today], change the time format under the Expression field in the Right hand pane from yyyy-MM-dd (ASCII Format) to the format that was used locally on the machine say M/d/yyyy. After this hit the save button to save the changes.
Once this is complete rerun the Process Cube component and this time it should complete without any errors. The data should then begin to flow into the cube.
Keywords: Dimension
Today
Parsed
References: None |
Problem Statement: How can I change the exchanger geometry going from design to rating?
Updating a file with the exchanger designed and changing to rating mode impedes the user to change the geometry. | Solution: To change the exchanger geometry the Tube layout option in Input /Exchanger Geometry must be changed from Use existing layout to New (optimum) layout or to New layout to match tubecount.
Key Words
echanger, geometry, calculation mode
Keywords: None
References: None |
Problem Statement: How to convert a Shell & Tube Exchanger (Aspen Tasc+) file to a Shell & Tube Mechanical (Aspen TEAMS) file and vise versa | Solution: 1. Aspen Shell & Tube Exchanger (Aspen Tasc+) to Aspen Shell & Tube Mechanical (Aspen TEAMS):
Once the Aspen Shell & Tube Exchanger file (Aspen Tasc+ file) is run it can be exported to Aspen Shell &Tube Mechanical (Aspen TEAMS). To convert or transfer the Aspen Shell & Tube Exchanger file (Aspen Tasc+ file) to Aspen Shell &Tube Mechanical (Aspen TEAMS), on the main menu go to Run | Transfer and select the Aspen Shell & Tube Mechanical (Aspen TEAMS) and click OK. Now the geometry information will be transferred to Aspen Shell &Tube Mechanical (Aspen TEAMS).
To view the transferred geometry data click the Aspen Shell & Tube Mechanical (Aspen TEAMS) icon on the tool bar.
2. Aspen Shell & Tube Mechanical (Aspen TEAMS) to Aspen Shell & Tube Thermal (Aspen Tasc+).
Once the Aspen Shell & Tube Mechanical (Aspen TEAMS) file is run, the geometry of the exchanger can be exported or transferred into Aspen Shell & Tube Exchanger (Tasc+). To do this, on the main menu go to Run | Transfer and select the Aspen Shell & Tube (Aspen Tasc+) and click OK. Now the geometry information will be transferred to Aspen Shell & Tube Exchanger (Tasc+) and it can be viewed by clicking the Aspen Shell &Tube Exchanger (Aspen Tasc+) icon on the tool bar.
Note: In either case, both Aspen Shell &Tube Exchanger (Aspen Tasc+) and Aspen Shell &Tube Mechanical (Aspen TEAMS) file will be retained in the same file.
Keywords: Convert, Transfer, Shell&Tube Thermal, Shell&Tube Mechanical.
References: None |
Problem Statement: Why are the results missing for some of my streams and blocks even after selecting Load Results from the Run menu to load all of the results? | Solution: This usually happens because the streams and/or blocks have been excluded from the report. For streams, click on the Include Streams button on the Setup\Report Options\Streams form to see if any streams are available, but not included in the report. Similarly for blocks, click on the Include Blocks button on the Setup\Report Options\Blocks form to see if any blocks are not included. If you want all streams or blocks included and all new streams or blocks included, move all of the object to the Available list and make sure that there are no items in the Selected list. This is the default and all current and new blocks or streams will be reported.
The Include Streams or Blocks dialog box is used to select which streams or block to include in the report. By default, all streams or blocks will be included if you do not use this dialog box. If you select any or all streams or blocks on this form, and then add new streams to your flowsheet, the new streams or blocks will not be included automatically. Do not use this dialog box if you want all streams or blocks to always be included in the stream or blocks report.
Keywords:
References: None |
Problem Statement: When using SRK with STMNBS2, the results are different from earlier versions. | Solution: A number of changes to STEAMNBS and STMNBS2 calculations were made in the past several releases. SRK uses the steam tables to calculate the properties of water in a stream mixture. Difficulties arise when the stream is a temperature and pressure where pure water would not be in that state. For example a vapor stream that is below 100 C and 1 atm. Then, the steam table properties need to be extrapolated.
Rather than use the steam tables for water, the equation of state can be used to calculate the properties for all components. This is more consistent and will not lead to some of the issues of extrapolation. RKS-BM and RK-SOAVE both use the equation of state for all components.
These changes were all documented in the compatibility notes:
2006
Steam tables property methods STEAMNBS and STMNBS2 use improved routines for all analytical derivatives. Expect some minor differences in CP and CV, especially near the critical point.
For STMNBS2, for temperatures below 273.15 K, properties are now extrapolated linearly using the slope at 273.15 K. In previous versions the properties were calculated directly by the correlation.
For STEAMNBS, molar volume is now extrapolated below 273.15 K to fix a problem where the volume root may not be found (other properties have always been extrapolated).
V7.1
STMNBS2 Corrections
Some errors were corrected in the property calculations of the STMNBS2 steam table method. The changes include:
Correct formulation of Helmholtz energy (used to calculate Gibbs energy and entropy)
Rigorous fugacity coefficient calculation from Gibbs energy. This property used to be ideal in past versions.
The changes affect calculation of fugacity coefficient (PHI, PHIMX), enthalpy (H, HMX), entropy (S, SMX), and Gibbs energy (G, GMX) and their derivatives. Different values of these properties should be expected:
In simulation models using the STMNBS2 method
In simulation models with STMNBS2 as free-water method, in these cases:
If free-water phase is present
When water solubility option 0 or 5 is selected (in which case the free-water method is used to calculate fugacity coefficients of water, even if free-water is not selected in Valid Phases)
This may lead to different phase equilibrium and compressor/turbine results in these simulations. Enthalpy values calculated by the old version were valid. Every effort was made to keep the enthalpy values unchanged.
Entropy results may differ by 1-10% in some simulations. Compressor power output (due to the entropy change) may be affected up to 10%. K-values of water (due to the fugacity change) may be affected 2-3%.
A second option code has been added to the ESSTEAM and ESSTEAM0 models, with default value = 1, which includes all of the above corrections when these models are used by STMNBS2. With this option code set to 0, only the Helmholtz energy is corrected; this means that, with this option code, the entropy and Gibbs energy will be different but the enthalpy and fugacity coefficient from STMNBS2 will be the same as in previous versions. Setting this 2nd option code to 0 will allow you to reproduce old simulation results in most cases, except entropy of the streams will be different. Compressor/turbine results may be different than in past versions even with this option, due to the changed entropy.
V7.2
STMNBS2 vapor fugacity
The change to STMNBS2 in V7.1 which allowed the fugacity of water to be calculated from Gibbs energy caused some poor extrapolations in calculations where the vapor phase fugacity is required while the condition is liquid in reality. This was changed in V7.1 CP2 and in V7.2 so that the vapor fugacity is calculated at the saturated vapor pressure at the system temperature in these cases. This should give more reasonable results in these cases.
V7.3
Steam table method STMNBS2 was modified in two ways which may lead to different results. The results of the previous version can be reproduced by setting the value of option code 2 of STMNBS2 to 1 when it is called directly, and to 0 when it is used as the free-water method in conjunction with an equation of state, such as SRK.
A new option for option code 2 (value = 2) was added, which performs the same rigorous fugacity calculations from Gibbs energy and corrected enthalpy departure as value 1, but uses the Aspen Plus root search method instead of the STMNBS2 root search method. This is more robust and less likely to lead to flash failures where a real root cannot be found.
A bug was fixed in the handling of option codes when STMNBS2 is used as the free-water method for equations of state such as SRK. Previously, option code 2 was ignored in this case and the original fugacity and enthalpy calculations of STMNBS2 were always used (equivalent to value 0).
Keywords: None
References: None |
Problem Statement: When using the PIPE or PIPELINE unit operation block to model a steam system (or any one component system) that has the potential to form some condensate, the following warning is written:
WARNING THERMAL OPTION IS REQUIRED FOR SINGLE COMPONENT MODEL UNLESS NPHASE=1 IS SPECIFIED. CALCULATIONS WILL CONTINUE WITH NPHASE=1, PHASE=LIQUID
Is this a serious problem? | Solution: Yes, to obtain reasonable results for the PIPE and PIPELINE blocks, the underlying causes for this warning must be remedied. By default, the PIPE and PIPELINE models use a constant temperature profile. This option is only reasonable for single component systems when the valid phase is vapor-only since it cannot handle phase change.
To remedy the problem in the PIPE block, go to the Setup form's THERMAL SPECIFICATION sheet and toggle the thermal specification type from constant temperature to ADIABATIC.
To remedy the problem in the PIPELINE, go to the Setup form's CONNECTIVITY sheet. Select a pipe segment and click on the edit button. Unlike the PIPE unit, the PIPELINE unit does not have a pre-specified adiabatic option, but you can create adiabatic conditions by doing the following:
Enter a guess for the inlet and outlet Ambient temperatures. The values are not important.
Go to the U-Value field and enter 0
Keywords: Pipe
Pipeline
References: None |
Problem Statement: How do I address the error message Unable to load dynamic link library zehetran.dll that appears when running the Aspen TASC 2004 interface with Aspen Plus 2004.1? | Solution: Install Aspen B-Jac 2004.1 from the AspenONE 2004 Update 1 DVD.
Keywords: heat exchanger
heatx
References: None |
Problem Statement: Are Chemistry calculations executed when the dielectric constant is very low? Chemistry calculations seem to be dropped if the average dielectric constant (CPDIEC) for the liquid phase is below a certain value. What is this value? Is it possible to have the chemistry calculations even if the average dielectric constant is below it? | Solution: In the apparent approach, electrolyte chemistry calculations are skipped if the mixture dielectric constant is less than 4. For the true approach, there is no such a check, and thus chemistry calculations are not skipped. This means that the results for the true and apparent approach will differ if the dielectric constant is less than 4.
If the dielectric constant of the mixture is less than 4 and the chemistry calculations are desired, either use the true approach or change the dielectric constant of the solvents in the liquid phase to a value slightly greater than 4. This will change the activity coefficient calculations a little bit, due to the Born term.
Keywords: electrolytes
References: None |
Problem Statement: Conversion of RateFrac to Aspen RateSep. | Solution: The attached document describes the commercial path if and how to migrate from RateFrac to Aspen RateSep.
Keywords:
References: None |
Problem Statement: What are the definitions of net duty and heat duty? | Solution: The heat duty QCALC in all blocks is calculated from the difference of enthalpies of inlet and outlet material streams.
The net heat duty is the sum of the inlet heat streams minus the actual (calculated) heat duty.
In general if you give only one specification (temperature or pressure) on the Input Specifications Sheet, the block uses the sum of the inlet heat streams as a duty specification. Otherwise, the block uses the inlet heat stream only to calculate the net heat duty. You can use an optional outlet heat stream for the net heat duty.
Keywords: NET-DUTY
QCALC
References: None |
Problem Statement: What are the recommended best ways to contact Technical Support? In other words, how do I reach AspenTech customer support when I have questions and issues regarding the AspenTech software we have licensed? | Solution: COMMUNICATION CHANNELS:
There are three ways to obtain assistance from AspenTech regarding the Aspen Retail family of products:
1. Send an Email to: [email protected]. Or you can send Email to product specific email boxes, for example, for Aspen Retail: [email protected]. For a list of specific email addresses, go to list of email addresses
2. Go to Web: http://support.aspentech.com/webteamasp/NewIssue.asp (you can go to http://support.aspentech.com and then click on submit issues)
3. Call technical support hotline telephone: 281-584-4357 or 888-996-7100 (Toll Free) for North America and Mexico, and +44 (0) 1189226555 (UK number) for Europe, Middle East, and Africa.
Customers in the Asia Pacific region can call their regional support centers. All our telephone numbers for the support centers around the world are listed support center telephone numbers.
Please always use any of the above to contact us, either on an existing issue or to submit a new one. Our support staff will create an incident number (a tracking number) for each issue (which we refer to as incident). Please reference the incident number in all your communications regarding that issue. You can also view the status and progress of your incidents from our support website using the Inciden Tracking (You can go to http://support.aspentech.com and then click on track issues)
NAVIGATION OF PHONE MENU:
When you call our technical support hotline, our phone menu will direct you:
- first select the product family by pressing a number on your phone (1 for Plant Operation products, 2 for Engineering Products, 3 for Supply Chain product)
- then select the specific product by pressing number. For example, under Supply Chain product, you can press 3 for Aspen Retail.
Note: You can shortcut the menu by pressing the numbers without listening through the instructions. For example, you can press 3, and 3 to reach the Aspen Retail support without having to wait for the instruction to complete.
When you are being assisted by our staff, please indicate the criticality (if the issue is time critical) to allow our staff to triage quickly and, if necessary, escalate it further to the appropriate expert(s) and/or management.
VOICE MAIL:
When all our staff members are on the phone assisting other customers, our hotline system will prompt you to leave either a regular voice mail or an emergency voice mail. Please leave an emergency voice mail if you have a critical issue. The emergency voice mail will trigger our paging system to alert the consultant on duty who will respond immediately, while a regular voice mail may take a couple of hours to respond.
OTHER SUPPORT TOOLS:
As we often use WebEx to view your system, your ability to get on WebEx is important. It is also important that you help us differentiate AspenTech product problems from those IT related such as network, third party software, hardware or business practice type of problems.
For a Critical issue, such as Production system down, unable to generate or collect critical data, or critical project at stand still, that requires an immediate attention, calling our hotline is the quickest way to get help.
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Other details about our service can be found in our Customer Service User Guide.
Keywords:
References: None |
Problem Statement: How does one enter standard volumetric flows for streams? What is standard volume flow and how is it differ from volume flow? | Solution: StdVol always refers to Standard Liquid Volume and should not be used for gases. The VOLUME basis in the Stream Input form can be used for both gases and liquids. VOLUME basis uses the state specifications (temp, pressure, Vfrac or duty) to calculate the actual stream volumetric flow. STDVOL is a liquid basis only, and should not be used for gases.
Stdvol as a basis for stream flow means standard liquid volume, which is defined at 1 atmosphere and defaults to 60?F. Click the Ref Temperature button to set a different reference temperature for standard liquid volume flow, mass concentration, or mole concentration specifications. To enter flows in standard vapor volume, choose Mole basis and select units such as scfm (standard cubic feet per minute) or scmh (standard cubic meters per hour). The standard conditions for standard vapor volume depend on the units selected. For standard cubic feet, they are 14.696 psia and 60?F. For standard cubic meters, they are 1 atm and 0?C. In both cases the standard flow assumes ideal gas.
There are a few ways to specify standard gas flow rates.
1. Use the Mole basis and choose MMSCFH or MMSCMH as the units.
2. Use the VOLUME basis but set T=60 F and P=1 ATM for stream. Then run the stream through a HEATER block to set the actual stream temperature and pressure.
3. Convert from standard cubic feet to lbmoles by multiplying 379.5 ft3/lbmole for an ideal gas.
The Stream Result form displays the total of the component flows, fractions, or concentrations entered for the stream. Use this value to check your input.
Note that the standard liquid volume flow (STDVOL-FLOW) can be very different from the volumetric flow rate (VOLUME-FLOW) of a stream. The standard liquid volume is defined at 60 F and 1 atm. The difference increases as the conditions diverge from 60 F and 1 atm. The volumetric flow rate of a stream may be very different from the standard liquid volume flow if the stream is vapor or has a significant amount of vapor. Standard vapor volume flows (MMSCFD) can be entered as mole flow (MOLE-FLOW) and selecting the appropriate units (SCFM or SCFD).
The standard liquid volume of a component at 60 F (VLSTD) is required if you use a standard liquid volume basis for:
Any unit operation model specification
The specification of any flowsheeting tool (for example, Design-Spec or Sensitivity)
The values for VLSTD parameter in the PURECOMP databank come from the API databook. It should be noted that the standard volume is not used to calculate densities in ASPEN PLUS. You can enter the parameter VLSTD on the Properties.Parameters.Unary.Scalar form.
[The prediction of the molar volume at 60 F can be used as an approximation of VLSTD for light gases when VLSTD is not in the databank. For some light gas components like H2, VLSTD is approximately the value predicted by the molar volume parameters (.0535 cum/kmol vs .068); however, for other components like CH4 the predicted value does not agree with VLSTD (.0535 vs .0993). This number is not very meaningful for light gases because these components are not liquids at this temperature and pressure.]
Keywords: None
References: None |
Problem Statement: Can you explain which parameter DHFORM (Ideal gas enthalpy of formation) or DHAQFM (Aqueous infinite dilution enthalpy of formation) is used for the calculation of the enthalpy for electrolyte systems? | Solution: DHFORM is used for all solvent components. For ElecNRTL, where mixed solvent can be used, DHFORM will be used for all the solvents.
DHAQFM is used for all ions (together with CPAQ0, the Aqueous phase heat capacity at infinite dilution).
For molecular solutes (e.g. components declared as Henry's components), if CPAP0 and DHAQFM are both provided, they will be used. If CPAQ0 is missing, then DHFORM is used together with Henry's constants to compute infinite dilution enthalpy for the solutes.
Keywords: electrolytes
heat of formation
aqueous
References: None |
Problem Statement: What can be done if a Broyden convergence block fails to converge? | Solution: If Broyden is converging only design specifications, providing a limit for Maximum step size on the Design Spec \ Vary sheet may improve convergence. Maximum step size is not used if the Broyden block is converging any Tear streams.
If the problem is highly nonlinear, the Step size on the Design Spec \ Vary sheet for numerical derivatives may need to be adjusted. As a rule of thumb, Step size should be approximately equal to the square root of the block tolerance.
Consider separating Design-Spec convergence from Tear stream convergence. Default Design spec nesting sequencing options are on the Convergence \ Conv Options \ Defaults \ Sequencing sheet. Alternatively, a convergence order can be defined on the Convergence \ Conv Order form using user defined Convergence blocks created using the Convergence \ Convergence Object Manager.
Initialize by converging tears to tolerance relative to tear tolerance. A good initial tolerance is 100 times final tolerance. This option can be found on the Convergence \ Conv Options \ Methods \ Broyden sheet by clicking on the Advanced Parameters button.
Switch from Sequential Modular (SM) mode to Equation-Oriented (EO) mode and replace the design spec with an EO spec group. In Aspen Plus 12.1, design specifications are automatically converted when swiching to EO if Use perturbation layer around closed model is selected on the Design Spec \ Input \ EO Options sheet. For the steps on how to move a Design Specification from SM mode to EO mode in Aspen Plus 11.1, seeSolution 105706.
Keywords: MAX-STEP-SIZE
design-spec
STEP-SIZE
References: None |
Problem Statement: During input translation of a flowsheet, the following message appears:
ERROR DURING FLOWSHEET ANALYSIS
CONVERGENCE BLOCK CONV1 CONTAINS THE FOLLOWING
DESIGN SPECS FROM ANOTHER MAXIMAL CYCLIC SUBSYSTEM.
SPEC2
THEREFORE IT CANNOT BE USED. IT WILL BE IGNORED.
What is a Maximal Cyclic Subsystem? | Solution: The sequencing algorithm considers the material (stream) and information (Calculator, design spec, etc) connections in the flowsheet and partitions the flowsheet into an ordered set of maximal cyclic subsystems (MCS). The flowsheet is solved by solving subsystems one at a time. The subsystems contain a set of objects such as unit operation blocks, design specs, tears, etc. The sequence algorithm does not allow a convergence block to include tear streams and/or design specs from different MCS' because it would require that several MCS' (including intermediate ones) be solved together. In the case above, the design specification SPEC2 should be removed from the convergence block CONV1. The user can specify a separate convergence block for SPEC2 or let Aspen Plus generate a convergence block automatically.
The method used to partition the flowsheet is that of Tarjan (SIAM J. Computing 1, 146-160, 1972). A description of the method may be found in the report by Duff and Reid (Harwell Report CSS29, 1976).
Keywords: convergence
References: None |
Problem Statement: How is it possible to delete an Aspen Plus file using VBA code? | Solution: The first step is to know the name and location of the file to be deleted. To delete a file in Visual Basic or VBA, it is extremely easy:
kill(filename)
where filename is the full path of the file (e.g. C:\My Simulation\ReactorModel.bkp).
If you want to delete all files in a directory, use the . wild card instead of a specific file name:
kill (C:\My Simulations\*.*)
If you would like to have the user choose what to delete, here is one way:
a=inputbox(Type in the filepath of what you want to delete)
'
kill(a)
end Sub
You can add other attributes to the inputbox if you wish (title, default text)
NOTE1: Unfortunately, no Confirm Delete dialog box will appear - the user must be very careful not to accidentally delete something important.
NOTE2: You might want to add ON ERROR checking in case the Kill command tries to delete a file that does not exist.
Keywords: activex, visual basic, VBA, Excel, delete, kill
References: None |
Problem Statement: Does the Aspen Plus/FactSage/ChemApp interface run with ChemApp Light? | Solution: ChemApp Light is the free version of ChemApp available from the GTT-Technologies website (www.gtt-technologies.de). The functionality of ChemApp Light is similar to the regular version of ChemApp, except for the following limitations:
ChemApp Light can only handle systems with up to three chemical elements.
ChemApp Light can only handle systems with up to 30 constituents (phase specific components)
ChemApp Light does not do target calculations.
ChemApp Light is only licensed for private, non-commercial purposes.
The Aspen Plus/FactSage/Chemapp interface calls whichever version of ChemApp can be found on the PC. As long as the simulation problem does not violate the first three restrictions, it may be feasible to use ChemApp Light with the Aspen Plus/FactSage/ChemApp interface.
The attached chemapplightV14.zip file contains an example problem that is able to run successfully with ChemApp Light. To run unzip all of the files in a clean directory. The pbzn-LS-chemsagedat.bkp is an example file that uses the Aspen/Chemapp Light interface. If the Fortran compiler is present, the name of the Chemsage .dat file can be specified with the CHEMSAGE Calculator block. The No-Fortran.bkp is a copy of file without the Chemsage Calculator block and uses a file with the name chemsage.dat by default. This example will run in V14.
Given that most Aspen Plus flowsheets contain target calculations in the form of PQ flashes (e.g. MIXER blocks), and that ChemApp Light is only licensed for non-commercial use, AspenTech does not officially support the use of ChemApp Light with the Aspen Plus/FactSage/ChemApp interface.
The following message is written to the Control Panel when the Aspen Plus/FactSage/ChemApp interface finds ChemApp Light:
INFORMATION WHILE PERFORMING INITIAL ENTHALPY CALCULATIONS FOR STREAM:
PBZN-LS
THE ASPEN PLUS/F*A*C*T/CHEMAPP INTERFACE
IS RUNNING WITH THE LIGHT VERSION OF CHEMAPP(ID=CALI)
CHEMAPP VERSION 816 IS PROVIDED BY GTT-TECHNOLOGIES
USE OF CHEMAPP LIGHT IS COVERED BY A LICENSE
AGREEMENT BETWEEN THE END USER AND GTT-TECHNOLOGIES
FOR DETAILS, SEE www.gtt-technologies.de
INFORMATION WHILE PERFORMING INITIAL ENTHALPY CALCULATIONS FOR STREAM:
PBZN-LS
NOTE THAT USE OF CHEMAPP LIGHT WITH THE
ASPEN PLUS/F*A*C*T/CHEMAPP INTERFACE IS NOT OFFICIALLY
SUPPORTED BY ASPENTECH. CHEMAPP LIGHT IS NOT
ABLE TO DO TARGET CALCULATIONS, INCLUDING PQ FLASHES.
SUBSEQUENT CALCULATIONS MAY NOT BE SUCCESSFULL.
The following two error messages are examples of error messages generated by the Aspen Plus/FactSage/ChemApp interface when the simulation problem exceeds the capabilities of ChemApp Light. These error messages were produced when trying to run PBZN-LS.BKP with ChemApp Light.
Block: CHEM-1 Model: USER2
ERROR
Target calculations are not permitted with ChemApp light
The error appeared after a call of TQCE
Target calculations are not permitted with ChemApp light
The error appeared after a call of TQCE
Block: MIX-2 Model: MIXER
*** SEVERE ERROR
Unknown ChemApp error in step 1 of equilibrium calculations. F*A*C*T/Aspen interface terminates. 515
Target calculations are not permitted with ChemApp light
The error appeared after a call of TQCE
Target calculations are not permitted with ChemApp light
The error appeared after a call of TQCE
Keywords: None
References: None |
Problem Statement: The default value for the number of RPlug nodes (nrange) is 10 in Aspen Plus. How can I change it? | Solution: Using the RPlug Report form, you can specify the spacing of the profile points in 2 ways:
Specify the number of profile intervals in the reactor. In this case, the profile points will be uniformly spaced along the length of the reactor. To use this option select Uniformly spaced profile points and give the Number of intervals.
Specify multiple profile sections. In this case, you can divide the reactor into several sections with varying lengths and number of intervals. By appropriately specifying the length and the number of intervals in each section, you can ensure that there are more profile points in regions with sharp gradients in temperature or concentration. To us this option, select Multiple sections with uniformly spaced profile points within each section on the Profiles sheet. Then, specify the section boundaries and number of intervals on the Sections sheet.
For each profile point, RPlug can optionally report these sets of data:
Temperature, pressure, and vapor fraction
Molar composition and attributes
Integer and real parameters from user subroutines
Profiles suitable for initialization of EO/Dynamic runs
By default, all of these except the integer and real parameters are reported.
Keywords: rplug
References: None |
Problem Statement: In the User Guide section of the Aspen documentation for Calculator Blocks it states:
In Fortran WRITE statements, you can use the following predefined variables for the unit number:
Unit
Destination
NTERM
Control Panel (if running from the user interface)
Terminal (if running interactively outside of the user interface), or
Log file (if running batch)
NRPT
Aspen Plus report
NHSTRY
Simulation history
I thought there was a list of other predefined variables that could be accessed/used inside a Calculator block? | Solution: There are a few other variables passed into Calculator blocks that can be used.
VARIABLE
I/O
TYPE-SPEC
DESCRIPTION AND RANGE
ICONVG
I/O
I
Convergence Flag for Looping
Only to be set if in a loop
(=2 continue, =0 stop)
IMISS
I
I
Integer Missing
RMISS
I
R
Real Missing
IPASS
I
I
Calculation control flag:
1 = Perform simulation calculations only
2 = Perform results calculations only
3 = Perform simulation and results calculations
4 = Write report
LMSG
I
I
Local Diagnostic Flag
KOUNT
I/O
I
Total Number of Lines Written
JPASS
I
I
Status check type
1 = final
2 = sensitivity
NBOPST
I
I
Physical Property Option Set Array
Keywords: Fortran
Common
References: None |
Problem Statement: The pressure-drop calculated by the PIPE/PIPELINE model appears to be wrong, if solids are present in the feed stream. What is the reason for this? What can be done to correct this? | Solution: The built-in pressure-drop correlations are suitable for either one-, two-, or three-phase vapor and liquid flows only. In other words, do not expect reliable results, if your inlet flow contains more or other phases (such as solids).
When solids are present in the feed to a PIPE/PIPELINE block, the calculations are inconsistent. This is caused by the way that Velocity is calculated. The basic model equation is:
Velocity = Mass Flowrate / (Density * Area)
The problem is that Density is the gas/liquid density and does NOT include solid substreams, whereas Mass Flowrate DOES include the solid substreams.
A workaround is to remove the solids in an SSPLIT block before the stream enters the pipeline block.
Finally, to model pressure-drop in a system which includes solids, the only consistentSolution is to write a user-defined pressure-drop correlation. Aspen Plus provides a Fortran template (USRPIP.f) in \Program Files\AspenTech\Aspen Plus 11.1\Engine\user as a starting point for this work.
Keywords: PIPE
PIPELINE
pressure
drop
solids
References: None |
Problem Statement: The inclustion of a statement similar to:
#include ppexec_user.cmn ! Your comment
causes this error:
f90: Severe: The input stream is empty | Solution: You must not put an comment in the Input-Line.
For example this:
#include ppexec_user.cmn ! Your comment
should be replaced by
! Your comment
#include ppexec_user.cmn
Keywords: Fortran
error message
input stream empty
References: None |
Problem Statement: Are Polymers Plus features supported in equation oriented | Solution: mode in Aspen Plus?
Solution
Generally speaking, Polymers Plus does not support Equation Oriented (EO)Solution method because polymer attributes are not supported in EO calculations. This means that the EO method can not be used if a polymer component exists.
However, in many cases, polymer plants have sections with polymer components (e.g. reactors and separation units right after reactors) and sections without polymer components (e.g. downstream separation/recovery units). The Mixed Mode (Sequential Modular + Equation Oriented) can be used in such way that Sequential Modular (SM) is used for the polymer sections and Equation Oriented (EO) is used for the non-polymer sections.
Keywords: COMP-ATTR
Component Attributes
References: None |
Problem Statement: When creating a plot using Sensitivity Analysis, there are several curves which appear in a particular order; however, the legend for each curve does not show the same order, even though the colors and patterns are correctly displayed. This looks confusing as one would expect the top curve to correspond to the top curve described in the legend. How can the plot be drawn in a way that makes the curves and the legend consistent? | Solution: The user cannot reorder the legend. However, the user does get to pick the order in which curves are added to the plot in the first place. The order that the curves are added are the order that they appear in the legend. To get the legend to look as desired, the plot will have to be created adding one curve to the Y-axis at a time, selecting the curves in the order the legend should have. Steps to do this are described below.
Steps
1. Create the plot as usual, but only for one of the variables wanted in the Y-axis. This will be the first variable that should appear at the top of the legend (so the top most curve).
2. Leaving the plot open the second data column should be selected from the table and chosen again as the Y-axis Variable in the Plot menu.
3. Then go to the Plot menu again and choose Add New Curve.... A list with currently open plots will appear. Select the desired plot and the new curve will be added to the plot with its legend just below the first one.
4. Repeat procedure as many times as the number of curves required to be added.
The alternative would be to transfer the table with results to Excel and create the plot there making use of Excel plot features.
Keywords: plot order
sensitivity
References: None |
Problem Statement: How is it best to deploy Aspen Plus/Properties across an organization most effectively when you have standardized in-house property subroutines? | Solution: If you use the %APRSYS%\Inhouse directory to store common customizations that include dynamically linked user routines (for Properties or Unit Operation models), you can store your custom DLLs in this directory and have them linked automatically without having to ensure all users point to the DLLs, DLOPT or DEF files in all their simulations. To do this, copy the relevant files to %APRSYS%\Inhouse directory, along with a DLOPT file (e.g., InhouseDLL.dlopt) that points to files in this directory and modify the aprsysfiles.def in %APRSYS%\Engine\Xeq to reference the new DLOPT file by adding the following line at the bottom of aprsysfiles.def: DLOPT: ${APRSYS}\INHOUSE\InhouseDLL.dlopt
Here is an example of the contents of the DLOPT file (InhouseDLL.dlopt): ! Search the system-level Inhouse directory structure
%APRSYS%\Inhouse\UserRoutines\*.dll
! You can even use a UNC path to reference routines to be dynamically linked
! \\MyComputer\MyShare\Plug\*.dll
If you have a local version of one of the routines that you are using (for testing, etc), it can still be used in preference to the default system version referenced in the aprsysfiles.def.
Keywords:
References: None |
Problem Statement: Incorrect results are returned when using a property package exported from Aspen Plus or Aspen Properties to perform molefraction derivative calculations (typically, the derivatives are returned equal to zero). | Solution: You must configure Aspen Plus or Aspen Properties to perform molefraction derivative calculations if you want to use them in a CAPE-OPEN package exported from Aspen Plus or Aspen Properties.
To enable this option, go to the Setup folder in the data browser, select Simulation Options, and check the option Require calculations of molar fraction derivatives
Note that for existing .COTA files, after selecting the checkbox, you have to manually remove the existing.appdf file. Otherwise, even if you re-run the calculations, these molfraction properties will still not be calculated.
Aspen Plus screen capture:
Aspen Properties screen capture:
Keywords:
References: None |
Problem Statement: What is CMAX displayed on the SQP history form? | Solution: CMAX is the maximum constraint violation for active constraints. Constraint values are scaled using the constraint tolerance. Note that CMAX can differ from the violations observed in tabulated constraint values because CMAX is calculated after each optimization step, while the SQP algorithm makes one final pass through the flowsheet to re-evaluate the constraints and objective function. Tightening convergence tolerances will reduce the amount of this difference.
Keywords: SQP
References: None |
Problem Statement: What should be done if physical property parameter data are unavailable in the Aspen Plus databanks? | Solution: Property data should be used to regress the property parameters used in the property models. The recommended path in the search for data is as follows:
Critically evaluated data sources
Non-evaluated sources
Experimental measurements
Estimation techniques to fill the gaps
Items [1] and [2] are covered in document 3063. Item [3] is discussed in document 3340. Item [4] is the topic of document 3339.
Keywords: pces
data
drs
References: None |
Problem Statement: This knowledge base article describes the Aspen Reporting Framework product. | Solution: Aspen Reporting Framework (ARF) is a new application that emerged with an idea to integrate the data from different applications under one single structure so that it can be used extensively for reporting purposes instead of relying on application specific tools to generate reports. The underlying technology within Aspen Reporting Framework uses the capability of Microsoft SQL Server Analysis Services and OLAP (Online Analytical Processing) which helps accelerate the execution time to quickly provide data from the multi-dimensional analytical queries to Aspen Operations Domain Model (ODM).
Along with this, Aspen Reporting Framework uses a publisher-subscriber model in which Aspen Reporting Framework subscribes to all the plans and schedules published from various AspenTech applications such as Aspen Advisor, Aspen PIMS and Aspen Orion. The data from these varied applications that are in ODM is stored in data warehouse and then data is converted to several business data blocks that focus on inventory, production, consumption, supply and demand by Aspen Reporting Framework. In turn these data blocks are generated into an OLAP cube that can be viewed from Microsoft SQL Server Business Intelligence Development Studio (BIDS) in which material and equipment dimensions are hierarchically arranged to improve the data analysis and observation.
The following image shows the Aspen Reporting Framework GUI with different tabs that needs to be configured to start subscribing for the data from different publisher applications.
After configuring Aspen Reporting Framework to get the data flow into the OLAP cube the following image from BIDS shows a glimpse on how hierarchical data can be viewed by specific equipment and material.
Keywords: Aspen Reporting Framework
Plan vs Actual
References: None |
Problem Statement: There is no unit of measure given in Aspen Plus for the Bond Work Index used in the Crusher model. Are you using exactly the same units as in Perry's Handbook? An example file uses a Bond Work Index of 61270, which is way above the listed ones in Perry, that go from 1 to 150. Is this reasonable? | Solution: Bond work index is the work required to reduce a unit weight from a theoretical infinite size to 80% passing a diameter of 100 micrometers. Bond Work Index and Hardgrove Grindability Index do have units. The units are: J/kg for SI, kWhr/ton for ENG and MET, and an additional KJ/kg. The conversion between J/kg and KWhr/ton is 3.968321d3. That is 1 KWhr/ton = 3968.321 J/kg.
The values in table 8-1and in Perry's Chemical Engineers' Handbook, 6th edition are in KWhr/ton.
If the example is using SI units, then 61270 J/kg is about 15.4 KWhr/ton, which is reasonable.
Fixed in Version
2006 will have the units noted in the GUI.
Keywords: crusher
solids handling
mill
References: : CQ00197460 |
Problem Statement: After uninstalling the default release, file associations are lost. How can this be fixed? | Solution: If a user un-installs the default release, file associations are lost. So, if a user installs and then un-installs a release, when they double-click on (for example) a bkp file, the previous release of Aspen Plus will not start up. They can, however still start Aspen Plus from the start menu or an icon on their desktop. This problem cannot be fixed with the current architecture.
However,
1. If the user starts Aspen Plus (say from the start menu), Aspen Plus will fix the file associations. So, after the first time they run Aspen Plus, the file associations are fixed. The user needs to be an administrator for this to work.
2. For Aspen Plus 12.1 and higher, a small utility will be supplied which will fix the file associations. It will allow the user to pick which release will be the default (based on all the releases installed on the user's computer). It will also fix all other registry entries, just in case the un-install does not work completely. It will be similar to apwnsetup, but should be easier to run and will not give the user the option of breaking their Data Browser forms database.
3. To access the post-12.1 utility, go to Start Menu / All Programs / AspenTech / Aspen Engineering Suite / Aspen Plus 200x.x / Aspen Plus Registry Fix Utility. Choose the installed version you wish do associate files with.
Keywords:
References: None |
Problem Statement: In the attached file cumene-d.bkp, synchronize the simulation in Equation-Oriented (EO) | Solution: mode, and the Sequential Modular (SM) design specification DS-1 is converted to EO variables. In the Data\Flowsheeting Options\Design Spec\DS-1\EO variables, the variables created and their corresponding EO specification are as follows:
Variables
Spec
BLK.PRODUCT_CUMENE_MOLEFRAC
CALC
VARY.COOL_PARAM_TEMP
CALC
BLK.SPECLH
CALC
BLK.SPECRH
CALC
All of these variables have a specification of CALC (calculated). Where is the target variable which is CONST (constant) that I can set a new value for?
How do I change the target of the design specification in EO mode?
Solution
In order to accomplish this in EO, a local parameter variable needs to be defined and specified as the Target, instead of as a constant value. Set the initial value of this variable to the value used for SM, then modify the value of this variable to adjust the target of the Design-Spec in EO.
This technique has been demonstrated in the attached file EO target.bkp. On the Data\Flowsheeting Options\Design Spec\DS-1 form, a variable called LOCAL is created with variable type LOCAL-PARAMETER and the initial value set to 0.98 (SM value). Then, on the Data\Flowsheeting Options\Design Spec\DS-1\Input\Spec sheet, the Target field is set as LOCAL i.e. PURITY = LOCAL.
The EO variables created and their specification are now as follows:
BLK.PRODUCT_CUMENE_MOLEFRAC
CALC
BLK_LOCAL_PARAM_LOCAL
CONST
VARY.COOL_PARAM_TEMP
CALC
BLK.SPECLH
CALC
BLK.SPECRH
CALC
The design specification target is variable LOCAL, which has a constant specification which means that the value can be changed by the user. To now change the value of the design specification target (from the SMSolution value), specify the value of variable LOCAL on the Data\Flowsheeting Options\Design Spec\DS-1\EO Input sheet.
Keywords:
References: None |
Problem Statement: Is VB or VBA source code case sensitive? | Solution: The Aspen Plus Path-to-Node names used in VB/VBA soure ARE case sensitive. In the Aspen Plus Variable explorer, you will notice that nearly all path-to-node names are MIXED case. For this reason, we recommend that users copy/paste the Path-To-Node names directly from the Aspen Plus Variable explorer. In version 11.1.x and earlier, the text in the the Variable Explorer's path-to-node name field can be copied only by highlighting the text and then clicking the right mouse button. In version 12.1 and later, Cntrl-C, and the menu bar's copy tool, and the EDIT pull-down menu's copy feature can also be used.
The Visual Basic editor automatically changes the case on any VB command, regardless of what case the user originally typed. Unfortunately, there are some sequence of events that also cause the VB editor to change the case of the Aspen Plus path-to-node name. A good way to check this is to copy/paste the path-to-node name as a comment (') immediately above the executable statement.
Keywords:
References: None |
Problem Statement: Can a user Pressure drop routine be used for a Pipeline block? | Solution: Attached is a simple example of a user pressure drop subroutine for a Pipeline block.
User subroutines are only used for 2-phase flow. User Pressure drop routine is not used for 1-phase flow. When the composition is all liquid, Darcy''s Law is used.
Keywords: user fortran
pipe pipeline
References: None |
Problem Statement: Can the total massflow of a stream, including both the mixed and solid substreams, be accessed? | Solution: Yes, The Property Set MASSFLMX can be used with the ALL qualifier for substreams. The flow will include Mixed, CISOLID and NC substreams.
Some other properties that can be tabulated for ALL substreams are as follows:
PROPNAME
Description
GMX
Free energy of mixture
HMX
Enthalpy of mixture
LFRAC
Liquid fraction
MASSCONC
Mass concentration
MASSFLMX
Mass flow rate of mixture
MASSFLOW
Mass flow rate of components in mixture
MASSFRAC
Mass fraction
MASSSFRAC
Mass solid fraction
MASSVFRAC
Mass vapor fraction
MOLECONC
Molar concentration
MOLEFLMX
Mole flow rate of mixture
MOLEFLOW
Mole flow rate of components in mixture
MOLEFRAC
Mole fraction
MWMX
Molecular weight of mixture
RHOMX
Density of mixture
SFRAC
Solid fraction
SMX
Entropy of mixture
VFRAC
Mole vapor fraction
VMX
Volume of mixture
VOLFLMX
Volume flow rate of mixture
These properties can be printed in the stream summary or report file (seeSolution 3005) or used in Design Specifications, Sensitivity, Analysis, Calculator blocks, etc.
Keywords: prop-set
substreams
References: None |
Problem Statement: It is not possible to access the cost related to utility usage within a single block directly. How can this cost be obtained? | Solution: In the attached example file, Fortran Calculator block has been added to calculate the individual unit operation cooling cost.
Two variables, B3REQ and B6REQ, have been created to access the utility cost for block B3 and B6. Calculated values can be seen after running the simulation in the Results form's 'Define variable' tab under \Flowsheeting Options\Calculator\C-1\Results.
Keywords: cost
utility
References: None |
Problem Statement: What version of OLI's ESP is supported in AES 2004 and 2004.1? | Solution: The Aspen OLI Interface readme file states that the version of OLI software required for AES 2004 is 6.7.
Keywords: None
References: None |
Problem Statement: Is there a way to do a Sensitivity Analysis that checks for choked flow in a valve? | Solution: Attached is an example file.
The variable CHOK-STAT is the flag for the choking status. It changes from 3 to 2 when the flow is choked. In addition, there will be errors for the sensitivity cases when the flow is choked. Check for choked flow should be specified on the Valve \ Input \ Calculation Options sheet.
If the minimum outlet pressure (P-OUT-R) is set equal to choked outlet pressure (CHOKE-POUT), they will match in the sensitivity analysis when the flow is choked.
Keywords: valve
CH-SET-PMIN=YES
References: None |
Problem Statement: Does Aspen Plus have built-in binary interaction parameters for vapor-liquid (VLE) and vapor-liquid-liquid equilibrium? | Solution: Aspen Plus 9.1-3 and higher have databanks with binary interaction parameters for both activity coefficient based and equation of state based property methods. After selecting the components and the property method, Aspen Plus shows the available binary parameters on the forms.
There are parameters for over 3600 component pairs for the following activity coefficient based property methods:
NRTL
UNIQUAC
WILSON
NRTL-RK
UNIQ-RK
WILS-RK
NRTL-HOC
UNIQ-HOC
WILS-HOC
In addition, there are 700 component pairs from LLE data for teh NRTL and UNIQUAC property methods, and 3500 component pairs for VLE parameters reported in DECHEMA.
In addition, Aspen Plus has built-in binary interaction parameters for the following equation of state based property methods:
RK-SOAVE (Redlich-Kwong-Soave)
PENG-ROB (Peng-Robinson)
BWR-LS (BWR-Lee-Starling)
LK-PLOCK (Lee-Kesler-Plocker)
The built-in databanks available are listed below:
Databank
Description
Property Methods
ASPEN-BM
Modified PR and RKS equations of state
(Boston-Mathias modifications).
PR-BM and RKS-BM
EOS-LIT
Standard RKS, standard PR, Lee-Kesler-Plocker,
BWR-Lee-Starling, and Hayden-O'Connell
equation-of-state models.
Obtained from the literature.
RK-SOAVE, PENG-ROB,
LK-PLOCK, BWR-LS and
*-HOC
BINARY
Henry's constants of about 60 solutes in water.
All property methods that allow Henry's law
ENRTL-RK
Binary and pair parameters for the
electrolyte NRTL model
ELECNRTL
HENRY
Henry's law constants for about 1600 sets
of solute-solvent pairs.
The solvents are water and other organic components.
Developed by AspenTech using Dortmund Data Bank.
All property methods
that allow Henry's law
LLE-ASPEN
NRTL and UNIQUAC models.
Developed by AspenTech for LLE applications
using Dortmund Data Bank.
All methods based on
NRTL and UNIQUAC models
LLE-LIT
UNIQUAC model obtained from the literature.
For LLE applications.
All methods based on
UNIQUAC model
SRK-ASPEN
SRK and modified SRK equations of state.
SRK and SRK-*
VLE-HOC
Wilson, NRTL and UNIQUAC models
with Hayden-O'Connell vapor EOS.
Developed by AspenTech for VLE applications
using Dortmund Data Bank.
WILS-HOC, NRTL-HOC,
UNIQ-HOC
VLE-IG
Wilson, NRTL and UNIQUAC models
with ideal gas vapor EOS.
Developed by AspenTech for VLE applications
using Dortmund Data Bank.
WILSON, NRTL, UNIQUAC
VLE-LIT
Wilson, NRTL and UNIQUAC models
with ideal gas vapor EOS,
obtained from the literature.
For VLE applications using Dortmund Data Bank.
WILSON, NRTL, UNIQUAC
VLE-RK
Wilson, NRTL and UNIQUAC models
with Redlich-Kwong EOS.
Developed by AspenTech for VLE applications
using Dortmund Data Bank.
WILS-RK, NRTL-RK, UNIQ-RK
For more information about built-in binary interaction parameters see the Aspen Property System help.
Key Words
opset
option set
option-set
Keywords: None
References: None |
Problem Statement: The Henry's constants for HCl/Water stored in the HENRY databank give poor results when modeling an electrolyte system. | Solution: The Henry's constants for HCl/Water stored in the HENRY databank should not be used. This set of parameters is not appropriate for use in modeling this electrolyte system. The values of HCL/WATER from the HENRY databank were kept for upward compatibility.
Use ELECNRTL with chemistry to model the dissociation of HCl in water, and use the binary parameters from the ENRTL-RK databank for the HENRY parameter for HCl in water.
Please note that the Henry's constants for this pair of components in the ENRTL-RK databank will not be changed and are recommended for use with the ElecNRTL property method when modeling HCl/Water system.
For upward compatibility reasons, if you need to use the Henry's constants that have been removed, you will need to go into the Properties/Parameters/Binary Interaction/Henry-1 form and enter the following values (in SI units):
Component i = HCL
Component j = H2O
Aij = -36.022701
Bij = 1215.0, 8.3707
Cij = -0.009593
Tlower = 253.15
Tupper = 293.15
Eij = 0
The screen should look as follows:
Input language parameters:
PROP-DATA HENRY-1
IN-UNITS SI
PROP-LIST HENRY
BPVAL HCL H2O -36.02270100 1215.000000 8.370700000 & -9.5930000E-3 &
253.1500000 293.1500000
Keywords: HENRY
HCL
ELECNRTL
ENRTL-RK
solubility
supercritical
solvent
solute
regression
CQ00123229
References: None |
Problem Statement: Is it possible to fit the U value of a heat exchanger from online data? | Solution: Here is an example of using Data-Fit to determine the U value of a condenser.
Data Fit was one of the new features in Aspen Plus 9. Users can use this feature to fit Aspen Plus models to plant and/or laboratory data.
A few points about Data-Fit:
It uses the maximum likelihood approach.
It permits users to fit any input variables accessible within Aspen Plus.
It allows users to reconcile measurements while fitting Aspen Plus variables.
How to define Data-Fit with Aspen Plus:
1. Define the measured data.
2. Define the data to be fitted.
3. Define the parameter(s) to be fitted.
Please see the Aspen Plus Help under Using Aspen Plus, Flowsheeting Options and Model Analysis Tools, Fitting a Simulation Model to Data for more details.
Keywords: datafit, heatx
References: None |
Problem Statement: Is it possible to install AspenTech Cumulative Hot Fixes Silently? | Solution: Download the .msp file or .exe file for the Cumulative Hot Fix from the Cumulative Hot Fix
document. For a .exe file use an extraction tool such as WinZip to extract the .msp file
from the self extracting executable.
Open a Command Prompt and type the following command line:
msiexec.exe /q /p {Full Path to newly extracted HotFix.msp\HotFix.msp filename} REINSTALL=ALL REINSTALL=omus e.g.
msiexec.exe /q /p C:\HotFixFolder\ACMHotFix12.1.1.msp REINSTALL=ALL REINSTALLMODE=omus
Should you wish to create a BAT file to perform this for you, provided the .msp file is in the same location as the BAT file, you may use the filename only,
e.g.
msiexec.exe /q /p ACMHotFix12.1.1.msp REINSTALL=ALL REINSTALLMODE=omus
A log file can be generated to monitor the success of the HotFix, to do this, append the following switch to the end of the command line.
/l {Desired Location\Desired filename}
e.g.
msiexec.exe /q /p C:\HotFixFolder\ACMHotFix12.1.1.msp REINSTALL=ALL REINSTALLMODE=omus /l %TEMP%\ACMHotFix12.1.1.log
At the bottom of the log file there will be a message stating either
Configuration failed. or
Configuration completed successfully.
Keywords:
References: None |
Problem Statement: When adjusting the volume translation parameter (RKCU0) in the SR-POLAR model, the observed change in the molar volume (or density) does not match the input value is some times. Why? | Solution: It is true that the parameter RKCU0 can be used to adjust the calculated molar volume of a component by translating the EOS results at a fixed temperature. However, for the SR-POLAR method the minimum volume is (b-c) as per the equation. When user specified c is larger than b the volume could be negative. To avoid this, Aspen Plus makes a check if (b-c) is less than zero and if so, set c=0.9b.
Keywords: Equations of state, mass density volume, CQ00557096
References: None |
Problem Statement: What are the techniques for the estimation of physical property parameters? | Solution: The basic estimation technique is as follows:
A. Component Substitution
If some or all the physical properties for a component are not available, the
use of the properties of chemically similar species may prove useful.
1. The component physical properties are not available
Find a chemically similar species in the Aspen Databank.
Assign the second component alias to the component ID
of the missing one.
Substitute the correct molecular weight via a Properties Parameters
entry.
2. Some of the component parameters are not available
Find a chemically similar species in the Aspen Databank.
Print the parameter values missing for the component of
interest using Retrieve Parameter Results from the Tools menu.
Enter the missing parameter values using a Properties Parameters
entry.
B. Homologous Series
This method is based on the extrapolation of a property on the basis of the number of
carbon atoms (usually). For example: to estimate the critical temperature of a
saturated hydrocarbon with 20 carbons, we extrapolate it from the critical
temperature dependency on the number of carbons for the smaller members of the
series. This is preferable than extrapolating with group contribution methods
(Joback, Ambrose, etc.) since their correlations do not have the structrure to
consider atom numbers.
C. Estimation Techniques based on Group Contribution Methods
1.
Keywords: None
References: s
Danner, R.P., and T.E. Daubert, Manual for Predicting Chemical Process
Design Data}, DIPPR (AIChE), New York, 1983 extant
Reid, R.C., J.M. Prausnitz, and B.E. Poling, The Properties of Gases and
Liquids}, 4th ed. McGraw-Hill, New York (1987)
2. Pure Component Property Prediction Methods
Boiling Point
Critical Properties
Vapor Pressure and Acentric Factor
Heats of Vapoeization
Heat, Entropy, and Free Energy of Formation
Ideal Gas, Liquid, and Solid Heat Capacities
Vapor and Liquid Densities
Transport Properties
van der Waals Volume and Area
3. Binary Equilibrium Prediction Methods
UNIFAC: Method for the prediciton of activity coefficients (there are
several flavors: UNIFAC, UNIFAC-Larsen, and UNIFAC-Dortmund)
ASOG: another group contribution technique for the prediction of activities
now supplanted by the UNIFAC family of methods |
Problem Statement: Do you require a separate RateSep license for RadFrac to be able to run rate-based calculations? | Solution: AspenTech is no longer selling any new RateFrac or BatchFrac licenses. Existing customers will still be allowed to use these products until they expire. These two products are replaced by RateSep and BatchSep which also require separate licenses. RateSep will be available in the Spring of 2005 in version 2004.1. BatchSep is already accessible in version 2004.
RateFrac files are easily converted to RateSep files through the Convert to utility available from the right mouse button when clicking on a RateFrac block.
RateSep is now a part of RadFrac Unit Operation. You can switch from equilibrium-based to rate-based calclulations with the RadFrac block.
To specify a rate-based column inside RadFrac, you must:
On the Setup | Configuration sheet, select Rate-Based for Calculation Type
Specify Tray Rating or Pack Rating sections for all stages that are rate-based
On the RateSep | Rate Based sheet of each rate-based section, select the Rate-based calculations checkbox.
You may also need to specify additional parameters on the RateSep forms of Tray Rating and Pack Rating sections or on the RateSep Setup form.
BatchSep is not a part of Aspen Plus, but is its own simulation tool with dynamic solvers using AspenTech's custom modeling technology. For more information on BatchSep, please visit our corporate website.
Keywords: None
References: None |
Problem Statement: When estimating the NRTL binary interaction parameters from infinite activity dilution data, how can one set the value of ALPHA (also known as Cij and NRTL/3)? | Solution: You need to enter the infinite activity coefficient data as GAMINF, select in the estimation (Properties, Estimation, Binary that you require the estimation of NRTL for all components (or selected binaries). Alternatively you can select the UNIFAC method for the estimation.
The value of Cij to be used for the estimation can be specified in the Properties, Parameters, Binary parameters, NRTL-1. It is possible to create a new column for the binary to be estimated and enter the appropriate value for CIJ (leave the other values to 0). Unless specified, the estimation uses a value of 0.3 for Cij.
Recommended Values for Different Types of Mixtures
Value
Type of Mixture
0.30
Nonpolar substances; nonpolar with polar non-associated liquids; small deviations from ideality
0.20
Saturated hydrocarbons with polar non-associated liquids and systems that exhibit liquid-liquid immiscibility
0.47
Strongly self-associated substances with nonpolar substances
If the data is at a single temperature, the property estimation system estimates only the second element of the parameter, such as NRTL/2. If the data cover a temperature range, PCES estimates both elements of the parameter, such as NRTL/1 and NRTL/2.
See for example the attached file, where the structures for water (A1) and benzene (A2) have been specified. The value of NRTL/3 has been specified to 0.123 (arbitrary value for illustration purposes only). Ficticious data for the infinite dilution activity coefficients have been entered as an example.
When Cij is set to 0.3, Bij = 413.6849770
When Cij is set ot 0.2, Bij = 387.6366520
Aspen Plus does not try to determine the polarity of the components or other ruls, it just uses the default value unless a value is found on the parameters form. The default value of 0.3 is coded directly in the code, so you can not alter the default value.
Help Text
The following text has been extracted from the on-line help and gives a bit of background information.
The property estimation system estimates binary parameters for the WILSON, NRTL, and UNIQUAC models, using infinite-dilution activity coefficients. Infinite-dilution activity coefficients can be supplied by:
Laboratory data entered on the Properties Data Mixture form, with data type=GAMINF
Estimation, using the UNIFAC, UNIF-LL, UNIF-DMD or UNIF-LBY method
For best results, use experimental infinite-dilution activity coefficient data. Of the four UNIFAC methods, the Dortmund method (UNIF-DMD) gives the most accurate estimate of infinite-dilution activity coefficients. This method is recommended. See UNIFAC, UNIFAC (Dortmund modified), and UNIFAC (Lyngby modified) for detailed descriptions of these methods. If the data is at a single temperature, PCES estimates only the second element of the parameter, such as WILSON/2. If the data cover a temperature range, PCES estimates both elements of the parameter, such as WILSON/1 and WILSON/2.
We will add the following information in version 2004.1 of Aspen Plus, to document the procedure explained above.
For NRTL, the parameter Cij (alpha) is set by default to 0.3, but it is possible to change this value. In some cases, it may be necessary to deviate from the 0.3 default. The reason is that the procedure estimates NRTL coefficients from limiting activity coefficients, and does not necessarily represent the concentration area (i.e. non-zero molefractions), on which the alpha parameter has a marked influence, especially in liquid-liquid equilibria. You can set Cij for the binary system to the required value before running the estimation.
Keywords: CQ00200699
PCES
References: None |
Problem Statement: How is the capacity factor used in packing sizing/rating calculations? | Solution: When doing a sizing calculation for packing, you supply the flooding approach and Aspen Plus calculates the diameter.
The flooding approach is defined as:
capacity factor at design conditions
% flooding =
Keywords: None
References: None |
Problem Statement: What is the easiest way copy and paste the Aspen Plus stream results into Microsoft Excel? | Solution: The easiest way to copy the stream results is to find the blank rectangle in the top left corner of the stream results table (circled in red). In one step, this highlights the data, and copies it to the clipboard. After the data is in the clipboard, open an Excel spreadsheet, click in a cell (i.e. A1) and then paste the data (type CTRL-V, or use the left mouse button to click on EDIT | PASTE, or click the right mouse button & then click on PASTE).
You can also selectively copy one or more columns by doing the following:
1) Click on the label above the column you wish to copy. If you want to copy more than one column, hold the control (Ctrl) key down and then left click on the additional columns of data
2) Copy the data to the clipboard (you can click on the Ctrl-C keys simultaneously, or click on the EDIT pull down menu and then COPY).
3) Paste the data into Excel (i.e. click on CTRL-V or click on the EDIT pull-down menu in Excel and click on PASTE).
Keywords: copy paste
References: None |
Problem Statement: Zoom In or Zoom Out on the flowsheet does not work. The flowsheet just stays the same. | Solution: Select Options from the Tools menu and go to the Grid/Scale sheet.
Check that the Zoom scale factor is not 1. This means that the view will not change when zooming. A value of 2 is the default.
Keywords:
References: None |
Problem Statement: In certain cases users may want to modify property parameters by using a Calculator block. For example if you have a non-conventional solid and want to calculate its properties as a function of the solid experimental analysis. The Calculator block is very useful for this purpose, but it is important to bear in mind that it will be exectued in a particular converrgence sequence and the parameters modified by it will affect the property calculations downstream in the sequence. That will cause a discontinuity, which may result in a convergence failure.
How can we ensure that the calculations are still consistent and smooth in order to avoid the convergece failure? | Solution: The problem may arise, in particular, if the Calculator block is also modifying the values of other variables, such as stream variables. Normally the variables in the Define sheet of the Calculator block are read in the order they appear. Aspen Plus then puts the variables back into the flowsheet one at a time and, when it is done with variables for the stream, it will flash it for the current property parameters entered. If, however, the next variable in the Define sheet is actually a property parameter that is also calculated and sent to the simulation, and this property parameter affects the enthalpy calculations, then the stream properties resulting from the flash are no longer in sync with this new value(s) because they were calculated for the old value(s). The result could be a failure to converge in the next block to be calculated.
The procedure is very much similar to what happens when you use more than one Property method in the flowsheet and you have a discontinuity at the point of switch between one block using a property method and the next block in the convergence sequence that uses a different property method. This particular case is described in more detail in document Overcoming discontinuous physical properties between flowsheet sections. The sameSolution can be applied here, i.e. placing a heater between the stream that needs to be reflashed once more after the property parameter has been modified by the Calculator.
AnotherSolution will be to ensure that the property parameter(s) to be modified by the Calculator are defined first on the DEFINE list, i.e. before the stream variables are modified. That means the new value for parameter(s) is put in place first, then the stream variables are modified, which will then result in the stream being flashed now with all the new values for the property parameters.
Keywords:
References: None |
Problem Statement: The value of PH25 and PH are not the same for a stream at 25 C at very low water concentration? Actually, both values look incorrect. | Solution: At very low water concentration, the concentration of the hydrogen (H+) or hydronium (H3O+) ion can be below the default cutoff of 1e-15. The trace threshold needs to be lower for the calculations to be accurate. The trace value can be changed in a Calculator block. For more information on how to change the trace value seeSolution 113089.
An example file is attached.
Notes on the example:
A Fortran compiler is required to run since RMIN and XMIN are changed in a common area.
The parameters for the MDEA system are not necessarily valid for concentrations over 50% MDEA. They are used for illustration purposes only.
Keywords: ASPEN PLUS, PROP-SET, PH, PH25, Electrolytes, ELECNRTL, PITZER, Property Set
References: None |
Problem Statement: How do you add help or message prompts to user defined Visual Basic input forms such as those described in the Getting Started Customizing Unit Operation Models manual? For example, is is possible to show the message Enter stream temperature when there is a click in an input cell for entering a temperature of a stream? | Solution: Make a call for each individual control using GotFocus(), as shown below. The example shows the code for the prompt that would appear when you click in the box MMTextBox1.
Eg.
Private Sub MMTextBox1_GotFocus()
RaiseEvent MMPrompt(Your prompt)
End Sub
Note individual input box / cell names can be determined by clicking on the box in the form you are creating (while you are in Visual Basic), and pressing the F4 key.
Keywords: user routine
user input form
Visual Basic
user2
vba
References: None |
Problem Statement: I have defined my own stream table format file (.tff). In it I included properties and specified phases. However, when I come to use it in my simulation I do not see the properties reported as expected. | Solution: By default properties are calculated for the total phase. Also the .tff used will only report results that are available for the stream as calculated by the engine. This includes all properties in Property Sets reported for the stream. The .tff does not calculate anything itself; it is just a format for reporting in the user interface.
Once you have defined your tff file and placed it the GUI\Xeq folder of your Aspen Plus installation or in your working directory, you wil be able to use it in the stream report of your simulation. You can then report the properties and and specific phases by creating a Property Set and including it in the stream report.
Attached is an example, which includes massflmx.tff. This tff is used to report the mixture mass flow and density (properties MASSFLMX and RHOMX) for each phase in the stream. Place it in your installation under:
Program Files\Aspentech\Aspen Plus 12.1\GUI\Xeq
The file massflmx-nopropset.bkp has no property set specified in the stream report. Running the simulation and looking at the stream results will show the FULL format. You can switch to MASSFLMX by clicking the Format field in the stream results sheet and scrolling down to find MASSFLMX. You will note that nothing is reported in this case.
Now you can specify a Property set and use it in the stream report.
Go to Properties \ Prop-Sets, click New and type in a name or accept PS-1.
Select Physical Properties MASSFLMX and RHOMX from the pull down menu in the Properties tab.
Select Vapor and Liquid phases n the Qualifiers tab to have both properties reported for each of these phases.
Now under Setup \ Report Options, select the Stream tab and click the Property Sets button.
Move the previously defined Property Set, e.g. PS-1, to the right hand side.
This has been completed in file massflmx-propset.bkp.
Now Run and view the stream report as above. When you select MASSFLMX stream format you will see both properties reported for both phases.
Keywords: tff
table file format
References: None |
Problem Statement: I have created a simulation in version 12.1 with H2O/HNO3 electrolyte system. I was getting fairly good results. I have loaded my simulation in version 2004, and I find that the densities of my liquid streams are far off the mark. For a 70%wt HNO3 | Solution: at 20C in water, I would expect a density of about 1400 kg/m3, but I get a value close to 2000 kg/m3! Why?
Solution
The parameters for H2O/HNO3 have been updated in version 2004. The previous parameters for the ELECNRTL activity coefficient model were giving incorrect results (seeSolution 112794 for details). As a consequence of the update of the activity coefficient parameters, the true composition of the mixture is now different. We have updated the Clarke density parameters to obtain a correct density.
When you create the simulation from scratch in version 2004 or above, the new parameters are used automatically, so you don't have to worry. The problem is specific to the case where the simulation has been created in version 12.1 or older and loaded in version 2004 or higher.
In fact, we have specified new values for NRTL parameter for the binary H2O/HNO3, and GMELCN parameters for H2O (H3O+ NO3-) and HNO3 (H3O+ NO3-). These parameters are not loaded automatically, thus leading to an inconsistent set of parameters.
To fix the problem and have a consistent set of parameters in your existing simulation, you need to:
- go to Parameters, Binary, NRTL-1
- select H2O as component i
- select HNO3 as component j
--> the new parameters for NRTL will be loaded from ENRTL-RK
- go to Electrolyte Pair, GMLECN-1
- select H2O for molecule i
- select H3O+ and NO3- for electrolyte j
--> the new parameter for GMELCN will be loaded (should be 0.45)
- select HNO3 for molecule i
- select H3O+ and NO3- for electrolyte j
--> the new parameter for GMELCN will be loaded (should be 0.45)
In order to keep the VLE results correct, the values for PLXANT also need to be changed.
Keywords: hno3
elecnrtl
electrolyte
References: None |
Problem Statement: Some times during flowsheet model execution you may want to stop the calculations if a specific condition is reached. How do you terminate the calculation without having to wait until the model runs to completion? | Solution: You can easily stop flowsheet calculations by using a CALCULATOR block and a Stop Point after a SEVERE ERROR calculation in the flowsheet. For example, create a CALCULATOR block to access the necessary variables to test the stop condition and make sure that the block is executed at the appropriate point in the calculation sequence. Test for the condition in the CALCULATOR block and if true, execute a FORTRAN divide by zero statement. Then under the Run | Stop Points menu in Aspen Plus select Stop on Severe error. You model must normally run without severe errors or the model execution may stop prematurely.
Note: If you save the simulation in BKP format, the Stop Point will not be saved in the file and will have to be re-selected when you re-open the file. If you save the simulation in APW format, the Stop Point will be saved in the file.
The attached sample file of the Cyclohexane Production Flowsheet tutorial stops flowsheet execution when the reactor block B2 calculated duty exceeds -9 MMBtu/hr. This method of stopping a simulation does not require a FORTRAN compiler.
Keywords: Calculator
Flowsheet execution
Stop Points
References: None |
Problem Statement: When I select reinitialize all blocks (or streams) in a Sensitivity block, what does Aspen Plus do exactly? Does it reinitialize every blocks on the flowsheet, or only the blocks that are in the sensitivity calculation loop? How about streams? All the streams of the flowsheet or only the streams connected to the blocks on the simulation? | Solution: Aspen Plus only re-initializes external feed streams to blocks inside the loop, and all outlet streams from blocks (whether connected or not to other blocks) inside the loop.
In some special cases, this logic cannot tell if there is a Calculator block which sets stream variables. Ideally, the Calculator block needs to also be inside to loop, so it can re-set after the re-init on the stream is done but we have found cases where the automatic sequence did not identify this issue. In this case, it may be necessary to specify execute after/before to force the calculator block inside the loop, or simply not use the Reinitialize stream option.
Keywords: reinit
sens
References: None |
Problem Statement: Where is the Aspen Plus Schema to interface to Aspen Plus XML? | Solution: Aspen Plus has the option to export summary file results in an XML format. These results are generated by traversing the summary file data structures and populating an XML DOM tree. Since the summary file data structure itself is driven by external data, the exact schema for the resultant XML results files vary from release to release and with user customizations. ThisSolution provides a utility application for generating an XMLSchema file(s) from the external data configuration for Aspen Plus.
The structure for the XML results file export is supplied at run-time by a number of XML (.xml) dictionary files delivered in the calculation engine dat directories: Aspen Plus xxxx\Engine\dat and APRSYSTEM xxxx\Engine\dat. The XML files are automatically generated from the Aspen Plus Variable Access definition files and contain the all the expected variables names and structures for each Aspen Plus record type in the summary file. Each record type is contained in a separate XML dictionary file; for example, BlockFlash2.xml contains the definitions for a Flash2 Block record. The dictionary XML files conform to the XMLSchema file, metadefn.xsd. Metadefn.xsd requires a few supporting XMLSchema files.
The command line utility application GenSummarySchema.exe reads one or more of these XML dictionary files and creates the XMLSchema that the XML results files that are exported against those dictionary files will follow. The usage is: GenSummarySchema [list of dictionary files] [/o output schema file] All dictionary files must be in the working directory. Wild cards may be used for the dictionary file names. For example, > GenSummarySchema StreamMaterial.xml /o f:\ap11bin\aplus\dat\summaryfile.xsd GenSummarySchema.exe requires that msxml4.dll is installed and registered.
The recommended usage is to only generate those records needed for a specific transformation or only those records present in a flowsheet. The second can be done by copying the referenced xml dictionary files to a temporary directory and executing GenSummarySchema *.xml from that directory. Generating a complete XMLSchema for all records will create a fairly large file and may cause performance problems when used by an application.
The XMLSchema-Instance namespace declaration is included the XML results file but not a schema location; noNamespaceSchemaLocation should be used to specify the schema.
Note: there are a few variables in the summary file structure and XML results files which are created dynamically at run-time and so are not specified in the dictionary files. These will not be present in the generated XMLSchema files, so do not attempt validate the XML result files on parse against the XMLSchema unless the dictionaries are manually edited to include the extra variable definitions.
There is no plan to document what is in the XML file. The variables in the Output section of the Variable Explorer are the same ones as in the XML file, although in some cases they are organized a little differently. To go from a field on a form to what the variable name is in the Variable Explorer, you Copy when you have highlighted the field, then in the left pane of the Variable Explorer, click on Go to node from the right mouse button. This will get you to that variable, which is the same name as the one in the XML file.
Keywords: xml
schema
References: None |
Problem Statement: Will multiple versions of Aspen Plus run on the same computer? | Solution: Yes, all major version of Aspen Plus will run concurrently if the system supports all of them. For example, it is possible to run 11.1, 12.1, 2004, and 2004.1 on XP or 2000. Backup files for these versions are only upwardly compatible (i.e. they can only be opened in that version and higher and cannot be opened in any lower version.)
Keywords: None
References: None |
Problem Statement: How do you access the composition profile over time for an RBATCH in a Calculator block? | Solution: You can access the RBATCH composition vector using the following input language:
As a vector:
VECTOR-DEF VEC2 PROFILE BLOCK=B1 &
SENTENCE=CONCPROF VARIABLE=VALUE
-OR-
As an individual element:
DEFINE V22 BLOCK-VAR BLOCK=B1 &
SENTENCE=CONCPROF VARIABLE=VALUE &
ID1=22
Where ID1 is the element number in the concentration profile vector.
The only issue is that you cannot specify the component explicitly. The vector is a list of mole-flows of each component in the order on the component list at each time point. For example,
Element
1
Component 1, Time 1
2
Component 2, Time 1
3
Component 3, Time 1
4
Component 4, Time 1
5
Component 5, Time 1
6
Component 6, Time 1
7
Component 1, Time 2
8
Component 2, Time 2
9
Component 3, Time 2
10
Component 4, Time 2
11
Component 5, Time 2
12
etc.
Component 6, Time 2
Keywords:
References: None |
Problem Statement: Aspen Plus/Aspen Properties has several different property methods (also called option sets) that all appear to be based on the Soave-Redlich-Kwong Equation of State. What is the difference between SRK, RK-SOAVE, RKS-BM, SRKKD (new for 12.1), and SRK-ML (new for 12.1)? Which one should be used? What are the option codes associated with each of these option sets? | Solution: All Soave-Redlich-Kwong based options sets call the same subroutines. However the physical property parameter names and the option codes that are used in the initialization and calling procedures are different. These define the data available for the calculations and how the calculations should proceed. If one is careful to set all of the physical property parameters and option codes to the same values, all of the option sets will calculate identical results.
New capabilities have been added to version 12.1 in the SRK, SRKKD and SRK-ML option sets:
SRK: SRK mixing rules have been extended with an asymmetric term based on the work by Mathias, Klotz and Prausnitz. This new Lij term enables SRK to better handle polar components.
SRKKD: SRKKD replaces the standard quadratic mixing rules with the Kabadi-Danner mixing rules between water and hydrocarbons. This method is recommend by API for water-hydrocarbon three phase applications. The special interaction parameters between water and hydrocarbons are automatically estimated using group contribution methods.
SRK-ML: The Gibbons-Laughton alpha function is used to enable better representation of pure component vapor pressures. Kij is not required to be symmetric. When Kij is not symmetric, the Lij for the extended mixing rules is calculated as Kji - Kij. SRK-ML is equivalent to SRK except for the unsymmetric Kij and the Gibbons-Laughton alpha function.
ALL: The Kij in all Soave-Redlich-Kwong based option sets has added functionality in making the Kij temperature dependent (see below).
Therefore, AspenTech recommends that SRK, SRKKD or SRK-ML be used for new simulations using the Soave-Redlich-Kwong equation of state. RK-SOAVE and RKS-BM are only included for upward compatibility of existing simulation files.
The form of the Soave-Redlich-Kwong equation of state is:
p = RT/(Vm + c - b) - a/((Vm + c) (Vm + c + b))
Where:
a = a0 + a1
a0 is the standard quadratic mixing term.
a0 = sumi ( sumj ( xi xj sqrt(ai aj) (1-kij) ))
a1 is an additional, asymmetric (polar) term introduced in version 12.1.
a1 = sumi xi ( sumj xj (ai aj)^1/6 lji )^3
b = sumi xi bi
c = sumi xi ci
ci = 0.40768 (R Tci / Pci) (0.29441 - zRAi)
First, each option set is assigned a particular list of pure component parameters and binary mixing rule parameters according to the following table.
Property
TC
PC
Accentric
Zrai
Kij
Lij
Method
Name
Name
Name
Name
Name
Name
SRK
SRKTC
SRKPC
SRKOMG
SRKZRA
See notes 1-3
SRKLIJ
RK-SOAVE
TCRKSS
PCRKSS
OMGRKSS
See note 8
See notes 4-6
RKSLBV
RKS-BM
TCRKS
PCRKS
OMGRKS
See note 8
See notes 4-6
RKSLBV
SRKKD
SRKTC
SRKPC
SRKOMG
SRKZRA
See notes 1-3
none
SRK-ML
SMLTC
SMLPC
SMLOMG
See note 8
SMLKIJ
See note 7
Notes:
1. In version 12.1 the SRK option set uses parameters named SRKKIJ and SRKLIJ.
SRKKIJ = SRKKIJ/1 + SRKKIJ/2 * Temp + SRKKIJ/3 / Temp
SRKKIJ/4 and SRKKIJ/5 provide an indication of the valid temperature range, however the temperature range is not limited to between SRKKIJ/4 and SRKKIJ/5.
SRKLIJ = SRKLIJ/1 + SRKLIJ/2 * Temp + SRKLIJ/3 / Temp
SRKLIJ/4 and SRKLIJ/5 provide an indication of the valid temperature range, however the temperature range is not limited to between SRKLIJ/4 and SRKLIJ/5.
2. In version 11.1 the SRK option set uses parameters SRKAIJ and SRKBIJ.
The overall Kij = SRKAIJ + SRKBIJ * Temp
3. When 11.1 files containing SRKAIJ and SRKBIJ are opened in 12.1:
SRKAIJ parameters are converted to SRKKIJ/1 parameters. SRKBIJ parameters are converted to SRKKIJ/2 parameters.
4. In version 12.1 the RK-SOAVE and RKS-BM option sets use parameters named RKSKBV and RKSLBV.
RKSKBV = RKSKBV/1 + RKSKBV/2 * Temp + RKSKBV/3 / Temp
RKSKBV/4 and RKSKBV/5 provide an indication of the valid temperature range, however the temperature range is not limited to between RKSKBV/4 and RKSKBV/5.
RKSLBV = RKSLBV/1 + RKSLBV/2 * Temp + RKSLBV/3 / Temp
RKSLBV/4 and RKSLBV/5 provide an indication of the valid temperature range, however the temperature range is not limited to between RKSLBV/4 and RKSLBV/5.
5. In version 11.1 the RK-SOAVE and RKS-BM option sets use parameter RKSKIJ.
RKSKIJ is a constant.
6. When 11.1 files containing RKSKIJ are opened in 12.1:
RKSKIJ parameters are converted to RKSKBV/1
7. In version 12.1 the SRK-ML option set uses parameters named SMLKIJ
SMLKIJ = SMLKIJ/1 + SMLKIJ/2 * Temp + SMLKIJ/3 / Temp
SMLKIJ/4 and SMLKIJ/5 provide an indication of the valid temperature range, however the temperature range is not limited to between SMLKIJ/4 and SMLKIJ/5.
Note that elements 1, 2 and 3 are not symmetric (Kij is not equal to Kji).
Internally, Lij is computed as Kji - Kij.
8. ci is only calculated if the Peneloux volume translation is enabled (see below). Peneloux volume translations can greatly increase the accuracy of liquid density calculations. If the option code for these option sets is switched to use volume translation, RKTZRA will be used.
Option Code Definitions for Soave-Redlich-Kwong based option sets:
Option Code 1 defines which Alpha function is used:
0 - Standard Alpha function for Tr < 1, Boston-Mathias alpha function for Tr>1 (Note - Standard Alpha function is always used for Helium, even if Tr > 1)
1 - Standard Alpha function for all components at all temperatures
2 - Graboski-Daubert Alpha function for H2, Standard Alpha function for all other components
3 - If SRKGLP parameters are present, Gibbons-Laughton Alpha function for all components, If SRKGLP parameters are missing, Standard Alpha function for Tr < 1, Boston-Mathias alpha function for Tr>1 (new in 12.1)
4 - Mathias Alpha function when Tr < 1, Modified Aspen Plus Alpha function when Tr > 1 (new in 12.1)
5 - Twu generalized alpha function (new in 12.2)
The Twu generalized alpha function behaves better at high omega since it does not have a minimum.
This is important for high molecular weight pseudo components. (Twu, C.H., Sim, W. D., and Tassone, V., Getting a Handle on Advanced Cubic Equations of State, Chemical Engineering Progress, 98(11): 58-65, November 2002.)
Option Code 2 defines the mixing rules:
0 - Standard Mixing Rules (includes new Lij term in 12.1)
1 - Kabadi-Danner Mixing Rules
2 - Standard Mixing Rules with unsymmetric Kij and Lij = Kij - Kji (new in 12.1)
Option Code 3 defines whether or not water is explicity identified and treated differently:
0 - Water is not explicity identified. It is treated as any other component.
1 - Water is explicitly identified. Water properties are calculated from the steam tables.
Option Code 4 defines whether or not the Peneloux liquid volume correction is used:
0 - Do not use the Peneloux liquid volume correction
1 - Use the Peneloux liquid volume correction
Option Code 5 defines how the cubic equation is solved:
0 - AnalyticalSolution according to Perry's 5th Edition, page 2-9
1 - Edmister and Lee NumericalSolution
(Applied Hydrocarbon Thermodynamics, Vol 1, 2nd Edition) (not recommended)
2 - Newton-Raphson NumericalSolution in VPROOT/LQROOT
(traditional method for AspenTech Equations of State)
Option Code 6 defines the logarithm used in calculating properties (New for 2006).
0 - Use true logarithm in calculating properties (default for Redlich-Kwong-Soave models)
1 - Use smoothed logarithm in calculating properties (default for SRK models)
Default Option Codes for Soave-Redlich-Kwong-Soave based property methods:
Propert Method
Models
Option_Code_Defaults
SRK
ESSRK/ESSRK0
2
0
1
1
0
RK-SOAVE
ESRKSTD/ESRKSTD0
1
0
0
0
2
RKS-BM
ESRKS/ESRKS0
0
0
0
0
2
SRKKD
ESSRK/ESSRK0
2
1
1
1
0
SRK-ML
ESRKSML/ESRKSML0
3
2
0
0
0
Note on the use of option codes:
Option codes are intended to give the user more control over the calculations in a single option set (e.g. how water is handled, or the choice of alpha function). AspenTech does not recommend the use of option codes to convert one option set to another. While this is likely to be OK if only a single Soave-Redlich-Kwong option set is used in a simulation, the potential for mistakes is high if multiple Soave-Redlich-Kwong option sets are used in a single simulation.
Keywords: None
References: None |
Problem Statement: Is it possible to access and display variables from Calculator, Design-Spec, or Sensitivity blocks via the Aspen Plus VB automation interface? | Solution: It is possible to access and display any variable from a Calculator, Design-Spec, or Sensitivity block via the Aspen Plus automation interface, as long as the variable is a DEFINE'd variable. For intermediate variables that are calculated within in-line Fortran, you must make the a PARAMETER for them to be available via the automation interface. Any Aspen Plus variable (including defined Calculator, Design Specification or Sensitivity block variables) could be displayed or specified using VB. For more information on defining and accessing Aspen Plus variables using the variable explorer tool in Aspen Plus please refer toSolutions 106094.
The syntax is as follows. An example with Excel is included that allows you to set the Design-Spec target and displays the final converged target value as well as a Calculator intermediate (Parameter).
Calculator:
Read-Var (before calcs) - Application.Tree.Data.Elements(Flowsheeting Options).Calculator.Elements(CALC-ID).Output.READ_VAL.Elements(n)
Write-Var (after calcs) - Application.Tree.Data.Elements(Flowsheeting Options).Calculator.Elements(CALC-ID).Output.WRITE_VAL.Elements(n)
Variable Name (FVN) - Application.Tree.Data.Elements(Flowsheeting Options).Calculator.Elements(CALC-ID).Output.VARID.Elements(n)
Variable Units - Application.Tree.Data.Elements(Flowsheeting Options).Calculator.Elements(CALC-ID).Output.VAR_UNIT.Elements(n)
DesignSpec:
Spec - Application.Tree.Data.Elements(Flowsheeting
Options).Elements(Design-Spec).Elements(DSPEC-ID).Input.EXPR1
Target - Application.Tree.Data.Elements(Flowsheeting
Options).Elements(Design-Spec).Elements(DSPEC-ID).Input.EXPR2
Calc SpecValue - Application.Tree.Data.Elements(Flowsheeting Options).Elements(Design-Spec).Elements(DSPEC-ID).Output.FINAL_VAL.1
Calc VaryValue - Application.Tree.Data.Convergence.Convergence.Elements (CVBLK-ID).Output.VAR_VAL.1
Error/Tol History - Application.Tree.Data.Convergence.Convergence.Elements (CVBLK-ID).Output.VAR_VAL2.Elements(iter#).Elements(var#)
Notes: If any portion of the variable path or ID has special characters (numbers only, embedded spaces, hypens, etc), you must use the abc.Elements(xyz) notation rather than just abc.xyz
Keywords: VB
VBA
Excel
References: None |
Problem Statement: What is HXFlux used for and why would it be used instead of HeatX? | Solution: The HXFlux block calculates heat transfer between a referenced heat sink and a heat source. It does not connect to any physical material or heat streams on the PFD. There are two default heat transfer modes in HXFLUX, convective heat transfer (default) and radiant heat transfer.
Convective heat, is the subject of thisSolution document. The driving force for the convective heat transfer is calculated as a function of the log-mean temperature difference (LMTD), rigorous or approximate.
The most common use of the HXFlux block is in conjunction with two simple Heater blocks connected by a heat stream. Often in large flowsheets, a HeatX block is replaced with two simple Heater blocks and heat stream, to reduce the complexity of the flowsheet and avoid the tear stream associated with the HeatX block. The disadvantage of this simplification is that the heat exchanger area and heat transfer coefficient cannot be incorporated into the simple Heater model calculations. When used in tandem with a HXFlux block, the Heater block can include the area and heat transfer coefficient in its calculations.
The HXFlux block can reference any material and/or heat stream on the flowsheet, i.e. the simple Heater block streams, and the heat exchanger area or heat transfer coefficient can either be specified or calculated according to the convective heat transfer equation:
Q = U*A*LMTD (where LMTD is a funtion of inlet and outlet, hold and cold temperatures)
Therefore, in the HXFlux block, you need to specify any 6 of the available 7 variables in the above equation:
Q - Duty specification or a heat stream (on PFD)
U - Heat transfer coefficient
A - Heat transfer area
Inlet hot stream - Temperature specification, material stream (on PFD) or EO variable name
Inlet cold stream - Temperature specification, material stream (on PFD) or EO variable name
Outlet hot stream - Temperature specification, material stream (on PFD) or EO variable name
Outlet cold stream - Temperature specification, material stream (on PFD) or EO variable name
The HXFlux block used with two simple heaters connected by a heat stream effectively does the same calculation as a short-cut HeatX design calculation (see example in attachment). However, the HXFlux configuration has these benefits over the shortcut HeatX model:
Avoids tearing the material stream of the HeatX block (simplifies flowsheet convergence and improves solver efficiency).
Allows direct reference of Equation Orientated (EO) variables for use in EO heat integration problems.
Heat transfer area for immersed bundles can be modeled.
For rigorous heat transfer calculations, use HeatX with the bundle geometry specified, or the Hetran or Aerotran (B-JAC) unit operations.
Keywords: HXFlux
HeatX
shortcut
heat integration
EO heat integration
References: None |
Problem Statement: Most property methods do not have routes for solid properties defined; however solid properties are indeed calculated if solids exist. How are properties for solids calculated when no property methods exist? What property method is used? | Solution: These properties are calculated by the routes defined in the IDEAL (SYSOP0) property method. These will be explicitly listed in all property methods for 2006.
Keywords: solids
References: None |
Problem Statement: How do you use Aspen Plus physical properties inside TASC and TASC heat exchanger models inside Aspen Plus? | Solution: Using Aspen Plus physical properties inside TASC
Recommended Method
This first method works with Aspen Plus v2004 and Aspen TASC v2004 with Cumulative Patch1. Both Aspen Plus and Aspen TASC must be installed on the PC.
If you are running Aspen TASC v2004 you should also download & install Cumulative Patch 1 from the support website http://support.aspentech.com Click on the Patches option on the left hand side and then choose Aspen TASC. The patch is called ?Aspen TASC 2004 Cumulative Patch 1 (CP1) - March 2005 (115477)? - it is an 8 MB download file and so takes a little while. If you don't have the patch you can still use this method but see step 8 below.
1. Either start a new Aspen Plus run and select components, and property methods, or open an existing Aspen Plus simulation.
2. Either add a new heater exchanger (HEATX) block along with feed and product streams, or use an existing HEATX block.
3. For a new exchanger, use the default Shortcut mode in the HEATX block and specify conditions for one of the outlet streams e.g. exit temperature, degrees sub-cooling etc. Ensure the overall performance is satisfactory and there is sufficient flow to avoid temperature crossover.
4.
Change the calculation mode in the HEATX block from Shortcut to Tasc-Rigorous, and change the calculation type to Simulation.
The ?Hetran/Aerotran/TASC Options? folder changes to a red & white colour. Click on the Next button (Na) to move to this folder.
5.
When running a TASC model inside Aspen Plus, you would normally enter the name of a TASC file that you have already made in this field. However, in this case you should enter the name of a new TASC file that does not yet exist. You should also include the path name. The file extension should be .TAI
If you forgot to change the calculation type from the default of Design then you will get this warning:
If so, select Yes to override the problem, and then go back to the previous form and change the calculation type to Simulation.
6. Next you should run the Aspen Plus simulation i.e. click on the Next button (Na). This TASC file named above does not yet exist but Aspen Plus will write the physical property data into it, and then stop because the TASC file has no heat exchanger details. You will get an error message similar to this:
Block: B1 Model: HEATX
** ERROR
ERROR WHILE READING INPUT FOR PROGRAM TASC
INSUFFICIENT GEOMETRY DATA IN TASC INPUT FILE
BLOCK WILL BE BYPASSED
However, you can then leave Aspen Plus and open that same TASC file in the TASC program and the properties part will have been filled in with the relevant Aspen Plus property data based upon the Aspen Plus feed stream compositions, temperatures and pressures.
7. By default, the properties will be generated at a single pressure in the TASC file. If you want properties at multiple pressures (3 pressures) do the following:
a. In the ?Hetran/Aerotran/TASC Options? for the HEATX block, switch to the Tab called Property Curves. For either or both of Hot stream & Cold stream change the pressure option from Isobaric to Multiple Isobaric.
b. Then switch to the Tab called Hetran/Aerotran/TASC Parameters and enter a maximum delta-P value for the Hot/Cold stream where you selected the Multiple Isobaric option.
8. If you have not installed Aspen Tasc 2004 Cumulative Patch 1, you can still use this approach for getting Aspen Plus properties into TASC. However, there is a bug, the first time Aspen Plus runs, when it gets to the heat exchanger block you get this message:
Block: B1 Model: HEATX
** ERROR
ERROR WHILE READING INPUT FOR PROGRAM TASC
TASC INPUT FILE NOT FOUND
BLOCK WILL BE BYPASSED
If you subsequently look at the TASC file it has zero size. Simply, re-initialize and re-run the Aspen Plus simulation this time you get the following error message
Block: B1 Model: HEATX
** ERROR
ERROR WHILE READING INPUT FOR PROGRAM TASC
INSUFFICIENT GEOMETRY DATA IN TASC INPUT FILE
BLOCK WILL BE BYPASSED
The second time, Aspen Plus will correctly write the property data into the TASC file - however, this bug is fixed in Cumulative Patch 1.
Alternative Method
This alternative method of getting Aspen Plus properties into TASC will also work with earlier versions of TASC and Aspen Plus. It uses the HTXINT utility program but is more complicated than the method outlined above.
1. First, inside Aspen Plus, you need to create heating/cooling curves that use the property set HXDESIGN as the set of properties to be reported.
The HXDESIGN Prop-set is present in most Aspen Plus templates, so if you started your simulation by using one of the templates (e.g. General with Metric Units) you will already have this property set. Look in the Properties > Prop-Sets folder in the Aspen Plus data browser to check this. The HXDESIGN property set contains all of the properties needed for heat exchanger design e.g. viscosity, thermal conductivity, heat duty and so on.
If you have not started your simulation with one of the standard templates and do not have the HXDESIGN property set, you can use File > Import, change the file type to Template and import, say, the General with Metric Units template. This will normally be located in directory:
C:\Program Files\AspenTech\Aspen Plus 2004\Gui\Templates\Simulations
2. Next either create a new heat exchanger (HEATX) block or use an existing one in your Aspen Plus simulation. The heat exchanger block will probably be using the default Shortcut calculation mode which is ok.
3.
Within the HEATX block, change to the Hot Hcurves folder and click on New to create a Hot stream curve.
Accept the default ID of 1.
4.
The property curves are generated across a range of 10 conditions. The default independent variable is Heat Duty i.e. it generates properties across a range of equal duty intervals. This is usually the best option to use. The curves always include the starting & end temperatures, and also the dew & bubble temperatures if these fall within the temperature range. Switch to the Tab called Additional Properties.
Move the HXDESIGN property set from the left pane into the right pane called Selected property sets.
5. Click on the Next button (Na) to run the simulation. Then return to this Hot Hcurves folder and go to the Tab called Results to see the Hot stream property curves.
6. If you also want the Cold side properties to be used in TASC repeat the above process but set up the property curves in the Cold HCurve folder.
7. You can set up these property curves in multiple HEATX blocks (also in Column Condensers & Reboilers, and in HEATER blocks).
8. Finally, exit from Aspen Plus and save your simulation as a backup (*.bkp) file.
(Use File > Save As and change the file type to Backup file, or use File > Export ).
9. You then run the HTXINT utility program which generates a property file (*.psf) for TASC. To run the interface program HTXINT, you need to open an Aspen command window (DOS...) with Start> Programs> AspenTech> Aspen Engineering Suite> Aspen Plus 12.1> Aspen Plus Simulation Engine. In the command window, use the DOS command (cd) to move to the folder where the bkp file has been saved
e.g. cd C:\Aspen.
At the DOS prompt, type:
HTXINT name of the bkp file without the extension
Then follow the prompts. You will be asked to select from a list of blocks which have property curves. - this is an example of a run:
D:\New Folder>htxint heatx-water-nc10
+
+ + +
+ + +
+ + + + +
+ + + + + + + + +
+ + + + + + + + + + +
+ + + + + + + + + + + + + + +
+ + + + + + + + + + + + + + +
+ + + + + + + + + + + + + + + + +
+ + + + + + + + + + + + + + + + + + + + +
+ + + + + + + + + + + + + + + + + + + + +
+ + + + + + + + + + + + + + + + + + + + +
+ + + + + + + + + + + + + + + + + + + + +
+ + + + + + + + + + + + + + + + +
+ + + + + + + + + + + + + + +
+ + + + + + +
+ + +
+ + + ASPEN PLUS Release 10.0
+ + + HTXINT Heat Exchanger Program Interface
+ + + Copyright (c) 1996 Aspen Technology, Inc.
+ + + All rights reserved.
+
Enter ? at any prompt for help.
Please enter the required interface. (B-JAC, HTFS, M-HTFS or HTRI) > M-HTFS
Please select the units to display the data. (SI, ENG or MET) > SI
Please enter the output file name. (Default is heatx-water-nc10.psf)
> test
File D:\New Folder\test.psf opened for output.
The following blocks have Hcurves.
+
Keywords: None
References: None |
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