question stringlengths 19 6.88k | answer stringlengths 38 33.3k |
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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, mo... |
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 calcula... |
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 Framewor... |
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.BO... | 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 f... |
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 followin... |
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 Geom... |
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 (*)
A... |
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 Met... |
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 engi... |
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 Exc... | 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 templa... |
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 fl... |
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 add... |
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... | 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... |
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 con... |
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... |
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 ... |
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 ... |
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 h... | 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 > Tube... |
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 ... |
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 follo... | 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... |
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... |
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 Summar... |
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 brou... |
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 driv... |
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 d... |
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 i... |
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... |
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 layo... | 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... |
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 domai... | 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\... |
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 thresh... | 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_X... |
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 ... |
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... |
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 the... |
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 o... | 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 c... |
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... |
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 fol... | 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 thi... |
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) t... |
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 ... |
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... |
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 CO... | 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 cann... |
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 ... | 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 dielec... |
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 Specifica... |
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: support@aspentech.com. Or you can send Email to product specific email boxes, for example, for Aspen Retail: aspenretail.support@aspentech.com. For a list ... |
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... |
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), i... |
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 ... |
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... |
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 ins... |
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.
C... |
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 Nu... |
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 o... | 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 = Per... |
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 calculati... |
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 sectio... |
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 corresp... | 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 t... |
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 D... |
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 Requ... |
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 p... |
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 docu... |
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 ... |
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... |
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 the... |
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... |
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 versi... |
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... |
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 'Def... |
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 shee... |
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 3... |
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 ... |
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 f... |
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 ... |
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 ... |
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 ... |
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... |
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... |
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 the... |
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 ... | 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 tim... |
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 t... |
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 tempe... | 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... |
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 repor... |
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).... |
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 th... |
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 conn... | 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... |
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 va... |
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 open... |
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 conc... |
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 ... | 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 on... |
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 av... |
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 subjec... |
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... |
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