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Problem Statement: Is there a Property Set (Prop-Set) to calculate Octane Number (Motor and Research)? | Solution: If you have entered data for Assay Data Analysis (ADA) as a Property Curve on the Assay/Blend | Property Curve| Petro Properties sheet, you have four options for reporting Octane Number (as determined from a fit of the curve). They are:
Parameter
Description
MOC-NO
Motor octane number
MOCNCRV
Motor octane num... |
Problem Statement: What is the reference temperature To in the power law expression for reaction kinetics? How should it be used? | Solution: A reference temperature (To) was added to the standard power law expression in Aspen Plus 10.0. In Aspen Plus 9, only the standard power law expression was available.
If To is entered in the power-law kinetic rate expression, the form of the equation is
rate of reaction = k (T/To)^n exp[ (-E/R) (1/T - 1/To) p... |
Problem Statement: The online-help of Aspen Custom Modeler provides an example for the use of the Results.CopyValues method.
The command shown in the example has the same function as the Advanced Copy dialog available from the Snapshot Management dialog box. That means it requires the specification of a flowsheet objec... | Solution: The required syntax to copy all variable values from a snapshot is:
Simulation.Results.CopyValues aResult, False, True, True, False, True, True, , ~
Keywords: Automation
Results
Snapshot
Copy
References: None |
Problem Statement: How do you select the Unit Of Measure and how do you add a new PhysicalQuantity? | Solution: For more information see the online documentation.
1 How do you select the Unit Of Measure (UOM)?
The user can change the UOM by selecting it using Tools\Units of Measurement and choosing the UOM from the built in list which consists of:
Metric
US
ENG
MET
SI
METCBAR
SI-CBAR
2 How do you add a new PhysicalQuan... |
Problem Statement: While running a data regression, what do the messages about constraints not satisfied mean?
There are two possible messages:
1. *** CANNOT SATISFY CONSTRAINTS ***
2. *** DRS CONVERGED IN X ITERATIONS, BUT CONSTRAINTS ARE NOT TIGHTLY CONVERGED ***
What is the difference? | Solution: The two messages about Constraints meet different conditions. The Britt-Lueke algorithm calculates a penalty function which is proportional to the sum of constraints.
If the penalty is greater that 0.0001 times the sum of square errors (the objective function) then the message is
*** CANNOT SATISFY CONSTRAINT... |
Problem Statement: Simple RadFrac column with free-water fails to converge. The organic phase is not even present on most stages. Why does this occur? | Solution: The free-water approach requires that you always have an organic phase. This is not a bug, but rather a limitation of the theory behind the free water calculations. TheSolution under these circumstances is to do rigorous 3-phase vapor-liquid-liquid (VLL) equilibrium calculations. In 2004 and higher, using dir... |
Problem Statement: How can stream results be copied to input forms to be used as tear estimates? | Solution: Simulation results for a stream can be copied onto the its input form in Aspen Plus 10.1 and later to provide tear stream estimates. This process is called Reconcile a stream.
Stream reconciliation can be very strategic in flowsheets with recycle loops. Once the flowsheet has converged, the results for the te... |
Problem Statement: How do I create a customized application template in Aspen Plus 10? | Solution: Aspen Plus provides a number of application types designed for various industries. Sometimes, this application type cannot be applied to your simulation. You can develop your own, defining default sets for a class of simulation not included in the Aspen Plus list provided. .
Template files are used to set you... |
Problem Statement: How to debug an Aspen Plus user subroutine with the Compaq Visual Fortran 6.x (6.1 or higher) debugger ? | Solution: It is assumed that Aspen Plus and the Compaq Visual Fortran 6.x have been installed on the same machine.
1. Compile the Fortran code with the ASPCOMP command and the dbg option: aspcomp filename dbg
2. Save the simulation as an input File
3. Modify the input file to include the following Stat... |
Problem Statement: The electrolyte wizard allows dissociated acids to represent the free hydrogen ion as either H3O+ or H+. How should I choose? | Solution: For almost all purposes the hydronium (H3O+) ion is a better choice.
It is a better physical model:
Vapor-liquid equilibrium data is better represented when the hydronium ion is selected. In aqueousSolution there are very few free hydrogen ions (bare protons). Hydrogen ions are solvated by water (hydrated). T... |
Problem Statement: I found that when I use NRTL, WILSON or UNIQUAC, the heat of mixing is not predicted accurately when I use the built-in parameters for NRTL, UNIQ, and WILSON. How do I fix this? | Solution: This is to be expected because the binary parameters in the databanks were regressed using VLE or LLE data only. Heat of mixing data was not used.
The heat of mixing for electrolyte systems is better predicted as many electrolyte parameters were regressed with VLE and Heat of mixing data.
To improve heat of m... |
Problem Statement: How is packing height measured in a column with respect to stages? Where does the top of sections begin? What is the Tray and Packing sizing/rating measuring convention? | Solution: The convention is to measure packing from the top of the column. In other words, stage 1 is at the top of the packing or height equal to 0. The same convention applies to any section of the column. The figure below illustrates a column with 6 ft of packing with 2 ft HETP (height equivalent to theoretical plat... |
Problem Statement: There are problems related to using Excel 2000 with a Calculator block.
These problems include:
The Excel template not loading and/or running
Problem loading CalcExcelAddin.xla.
Wordaround:
Apply the Aspen Engineering Suite 10.2 Service Pack 1 for Aspen Plus. Click this link to go to the Aspen Engin... | Solution: Display_view.cgi?key=104681
Alternatively install Aspen Engineering Suite 10.2 Update1 for Aspen Plus. Update1 is available on CD from the end of February 2001.
Fixed in Version:
Aspen Plus 10.2 Service Pack 1
Keywords: Calculator Block, Excel, Addin, Add-Ins,
References: None |
Problem Statement: What correlations are employed in Aspen Plus for the BK-10 method? | Solution: The Correlations for BK-10 were developed by AspenTech from the BK-10 charts published in the following references:
Prediction of Equilibrium Ratios from Monograms of Improved Accuracy. by B.C. Cajander, H.G. Hipkin and J.M. Lenoir, Journal of Chemical & Engineering Data, 5(3), 251, July, 1960
Predict K Valu... |
Problem Statement: During the installation of AES Core Component, after coping the files, the following error box appears:
C:\winnt\system32\ssiregi.exe
Then a second dialog box pops up stating:
System Process is Unable to load device: \systemroot\system32\drivers
device driver couldn''t be loaded Error status was 0xc0... | Solution: Clean up the device driver by running ssiregi.exe.
Run this program in one of two ways:
1 - From the Windows Start menu select Run, then type \winnt\system32 ssiregi.exe remove
2 - Open a DOS window and issuing the following commands.
cd \winnt\system32
run ssiregi.exe remove
Keywords: Activator Driver SSIPDD... |
Problem Statement: How do I change the default working directory in Aspen Plus? | Solution: There are two ways to set this.
1. The working directory can be set in the User Interface.
In V7.3 and earlier version, The working directory, can be set by selecting Tools, and then Options. Then select the Startup tab. Change the value in the text box labeled Default Working Directory.
Screenshot for V7.3 ... |
Problem Statement: Is it possible to calculate viscosity of a petroleum mixture's stream from Kinematic Viscosity data? | Solution: Aspen Plus does not have a feature to calculate viscosity from user specified kinematic viscosity curves.
Please see below on how viscosity and kinematic viscosity are calculated in Aspen Plus:
MUMX (Viscosity of a mixture) : calculated using a selected model. User can choose to use API, Andrade/DIPPR or User... |
Problem Statement: What are the different flooding factors reported for tray rating? | Solution: There are three measurements of flooding in trayed columns:
1. Flooding factor/approach
This is the jet flooding. If the vapor velocity is very high, it will start carrying a lot of liquid. It is reported as a ratio of the actual velocity to the velocity at flooding (calculated from a suitable correlati... |
Problem Statement: Is there a way to have VBA code determine the Aspen Plus version number of the currently open session? | Solution: There is not a version number property VBA code can probe directly. However, the VBA code can ask for the NAME of the simulation session. This will return a string containing the version number which can be parsed from the string. For example, asking VBA to store the name of the simulation in a variable calle... |
Problem Statement: How does one obtain the value of the reaction equilibrium constant Keq calculated by Aspen Plus in an RGibbs block? | Solution: To get the Keq (equilibrium constant of a reaction), one can use a Calculator block (called a Fortran block in Aspen Plus 10.1 and earlier) to calculate it.
Assuming that one has the following reaction: A + B <--> C + D, the definition of Keq is as follows:
Keq = a(C)*a(D)/[a(A)*a(B)]
where a(i) is the ... |
Problem Statement: Issuing asplmadm command with -s or -l options returns nothing, but user can check out a license from the server.
asplmadm -s command should provide a listing of all license manager servers on the network. asplmadm -l command should provide a listing of all available licenses on any server found on t... | Solution: asplmadm with -s or -l options will not work when the License manager and clients are in different subnets of the network.
To solve the problem, define the environment parameter ASP_LMhost to point to the IP address or full name of the License Server. Reboot the system afterwards.
Example Set ASP_LMhost = 10.... |
Problem Statement: Does a 3 Phase Radfrac use EO | Solution: Radfrac will work with 3 phase and EO but there are some limitations. By default it assumes that the three phase trays don't change when you go from SM to EO. A check is made for trivialSolutions in all cases by using Gibbs free energy minimization to see if some trays which were not trying to detect three ph... |
Problem Statement: Is it possible to access compressor type for a Compr block via a Define statement? | Solution: It is not possible to access this information from the Define form in the Graphical User Interface; however, it is possible to add it in input language. Attached is an example of accessing ITYPE.
The variable name for the compressor type is ITYPE. To access this variable, go to the EO Option sheet of a Calcul... |
Problem Statement: The following error occurs during AES 10.2 or AES 11.0 Core Component installation.
Failed to set special folder location 25 during Aspen Tech License Manager core component installation | Solution: IMPORTANT: This article contains information about editing the registry. Before you edit the registry, make sure you understand how to restore it if a problem occurs. For information about how to do this, view the Restoring the Registry Help topic in Regedit.exe or the Restoring a Registry Key Help topic in R... |
Problem Statement: On Windows 2000 when you run an Aspen Plus file where the linker is required, there is a failure with the error message:
LINK : fatal error LNK1181: cannot open input file dfordll.lib Link failure, status = 1181
asplink return code = 5 | Solution: There are two possible causes of this problem:
Compaq Visual Fortran (CVF) 6.1 or 6.5 has not been installed with command line option enabled.
You can check if this is the problem by trying to compile a sample Fortran program within a CMD prompt.
To fix this problem, you need to re-install the compiler paying... |
Problem Statement: Where is the PERFORATED PASS PLATES option in Aspen Acol+? In previous ACOL versions, the Perf.Pass Plates option was in the NOZZLE/HEADER Screen. | Solution: The PERFORATED PASS PLATES option in Aspen Acol+ is in the Input | Program Options | Methods/Correlations | Tube Side tab, where you can enter the Velocity heads for perforated pass plate pressure drop
In this input item you need to enter the number of velocity heads to be used for calculating the pressure dr... |
Problem Statement: Can the dew point for an electrolyte mixture such as sulfuric acid be predicted at high temperatures (T) and pressures (P)? | Solution: There are two problems with trying to predict dew points with electrolyte systems. One is the question of whether the physical property correlations are good at the high temperatures in question. The other problem is with flash convergence.
The physical properties in the ElecNRTL model are fit to aqueous syst... |
Problem Statement: Why is the saturated vapor heat capacity given by CPMX(V=1) different from CSATMX? | Solution: There are three heat capacities in common use: , and .
. represents the change in enthalpy with temperature at constant pressure.
. represents the change in enthalpy of a saturated liquid with temperature.
. represents the energy required to effect a temperature change while maintai... |
Problem Statement: How do I protect a bridge so the end user cannot change the Read From field in the links? | Solution: To protect a bridge so the end user can not change the Read From field, you should Disable Bridge Definer privileges for end user by going to Administrator tool as shown in screenshot below.
Keywords:
References: None |
Problem Statement: When attempting to run Aspen Plus the following error message occurs:
Form controls mmgeneric failed to load
gui\xeq\mmcontrolsvc.ocx could not register
gui\xeq\mmscrollarea.ocx could not register
gui\xeq\mmscrollareachild.ocx could not register | Solution: The problem is that when installing Aspen Plus, the above mentioned OCX''s were not registered correctly.
The steps to fix this problem are as follows:
Run RegFix.bat from \Program files\Aspentech\Aspen Plus xxxx\GUI\XEQ If this does not fix the problem, then go to step 2
Uninstall Aspen Plus, then run the R... |
Problem Statement: After adding a Hetran or Aerotran block to flowsheet, only the Block Options shows up under the Hetran block in the Data Browser. | Solution: Aspen Plus was installed without Aspen Hetran or Aspen Aerotran selected. To fix the problem, reinstall Aspen Plus over current installed copy. During the installation, select Custom Install and make sure to select all applicable products including Aspen Hetran or Aspen Aerotran. After the install is complete... |
Problem Statement: How is the Simpson''s shortcut method used in pressure relief calculations for nozzle flow? Can nozzle flow calculation time be reduced? | Solution: The equation for nozzle flow, which is used to model the valve and to convert from stagnation to flowing pressure and back, requires an integration with pressure as the independent variable. At each pressure value, the molar volume must be calculated. The rigorous way to do this is to perform a constant entro... |
Problem Statement: There are multiple warnings and repeated Out of environment space errors when using aspcomp to compile a Fortran routine in a Simulation Engine DOS window. | Solution: Modify the config.sys file located in your c:\ drive root directory to add the following line:
shell=c:\win95\command.com/p/e:1280
You may increase the allocation. Typically this is done in multiples of two to 4096, 8192, 16384, etc.
Then restart your PC and launch the Aspen Plus Simulation Engine window.
Key... |
Problem Statement: If you adjust a Property Method (formerly Option-Sets) using the Property Method's Models sheet, and then make changes on the Routes sheet, you will lose the changes you made on the Models sheet.
For example, if you want to use the WILS-HF Property Method with the NRTL activity coefficient (by changi... | Solution: By limiting how you can adjust Property Methods on a form, Aspen Plus prevents inconsistent specifications on a series of forms. This feature may be adjusted in future releases to allow you to modify the form measurements as you wish. However, there are two ways you can adjust specifications for the present r... |
Problem Statement: Is it possible to get fortran code to return integers? | Solution: There are several Fortran functions that can be used to convert a Real number to an Integer number. This type of conversion is often needed in distillation simulations where the number of stages is varied in a Sensitivity or Calculator blocks, and the feed stage depends on the number of stages. The feed stage... |
Problem Statement: When performing flash calculations, the Chemistry fails to converge, giving a message similar to the following error message:
*** SEVERE ERROR WHILE PERFORMING INITIAL ENTHALPY CALCULATIONS FOR STREAM:
1 (SINIT.6)
CHEMISTRY (chemid) N... | Solution: There are a number of reasons that might cause Chemistry not to converge. Generally, it is important to simplify the Chemistry and to make sure that all parameters are reasonable.
Check that the Chemistry is properly specified.
Try to simplify the problem by removing unnecessary reactions in the Chemistry pa... |
Problem Statement: Why does the stream result of API gravity differ from the input for a petroleum assay?
On the Assay/Blend input form, user entered a API bulk gravity of 40.8 for a particular assay. In the simulation stream input, user entered this assay component as the only component. However, when using prop-set t... | Solution: The descrepancy could be caused by the pseudocomponent cut temperature increment. Petroleum stream properties is a function of pseudocomponent composition, which is related to the number of cuts generated during assay data analysis. If the number of cuts is too few, or the cut interval is too large, then the ... |
Problem Statement: Double clicking on an APW file starts Aspen Plus; however, it disappears before the model is displayed. | Solution: This happens when the customer has updated to a higher version of Aspen Plus, but is using an APW file which was created with an earlier version. Aspen Plus Document (.apw) files are binary files and are not compatible across different versions or Service Pack levels of Aspen Plus. You must open the APW file ... |
Problem Statement: When using a HEATX block configured to use film coefficients calculated via a user specified power law, the values do not match the equivalent hand calculations. The hand calculations return U values that are an order of magnitude larger than the Aspen Plus results.
The equations were obtained the si... | Solution: The documentation is misleading about film coefficient calculations. The equation in the help file does not include the tubewall resistance and area correction for tube outside diameter (OD) and inside diameter (ID). The correct overall coefficient based on film coefficient should be:
UOT = USCAL/(FS + 1.0D0/... |
Problem Statement: Binary property analysis available from the Tools menu can display PXY, TXY or XY curve. Using them, we can know approximate azeotropic point; however, they do not show the exact composition of the point. | Solution: The best way to know the azeotropic point is to use Aspen Split. Alternatively, it is possible to calculate it by modeling McCabe-Thiele procedure using only Aspen Plus.
You can use the McCabe-Thiele procedure by following steps:
1. Put a flash block and a stream multiplier onto the flowsheet.
2. ... |
Problem Statement: How do you configure AES 11.1 applications to use the standalone FlexLM Licenses? | Solution: Save your standalone license key file onto C:\Program Files\Common Files\AspenTech\ALM (or any other suitable location).
Launch FlexLM License Management Selector from Start Menu\Programs\AspenTech\Common Utilities.
Click on Select Aspen License File to get a license.
Click on the Browse button to select t... |
Problem Statement: Customer is unable to use the asplmadm command to poll the License Manager Server and use Broadcast Mode in the License Management Selector program to access the License Manager.
The customer can access a License Manager if the name of the License Manager is entered in the License Management selector... | Solution: The network is not properly setup to allow network broadcasts.
The License Manager uses TCP Port 6142, registered to AspenTech. By default, network routers will block all broadcast traffic, to reduce network congestion. If the customer wants to use the asplmadm command, they must enable broadcasts for TCP por... |
Problem Statement: What is the relationship among SINGT1, SINGT2 and SPDROP (i.e., how do their relative values affect things, if at all) in the LSSQP solver? | Solution: LSSQP (Large-scale Sparse Successive Quadratic Programming algorithm) implements a variant of a class of successive quadratic programming (SQP) algorithms, for large scale optimization. It performs the optimization by solving a sequence of quadratic programming subproblems. For more information about the LSSQ... |
Problem Statement: If Henry's law is used to predict the solubility of a supercritical or light gas in a liquid, Aspen Properties has to solve the following phase equilibrium equation for each Henry's component:
x * GAMUS * H = y * PHIVMX * P
x, y : mole fractions in liquid and gas
GAMUS : unsymme... | Solution: Solubility for gases in liquid mixtures are rare and it is therefore useful to consider how thermodynamic relations may be used to estimate such solubilities from solubility data in single solvents. If we know at some temperature the solubility of gaseous solute s in solvent i, and in solvent j, and in solven... |
Problem Statement: Model Library is not visible anymore in the Aspen Plus Graphical User Interface. | Solution: First go through the points 1 to 4. If this does not help, proceed with points 5 to 14. The second part should only be done with the help of IS and after having made a backup of the current registry settings.
Load a simulation in Aspen Plus, go to View/Model Library, and UN-CHECK the Model Library.
Go back t... |
Problem Statement: When does it help to have multiple sets of generated pseudo components? | Solution: By default, Aspen Plus generates only one set of pseudocomponents to represent all of the streams. Sometimes, when the assays are VERY DIFFERENT (i.e. one is very paraffinic and another is very aromatic), even increasing the number of cut points won''t improve the curve fit to adequately handle the very diffe... |
Problem Statement: There are some important issues in raising a variable to a power, like for example in power law kinetics. For example, let's assume that we have a reaction:
A --> B
where the reaction rate is given by:
r = k0*CA^alpha
k0 is the reaction constant, CA the concentration of A, and alpha the reaction orde... | Solution: The following expression should give very accurate results, and prevent the problem at low concentrations:
r = k0*CA*(CA+epsilon)^(alpha -1)
where epsilon is a real parameter, set to a small value. This means that if CA becomes smaller than epsilon, the reaction rate will be quasi-linear, thus giving better p... |
Problem Statement: None of the pseudocomponents generated are shown on the SEP2 block input form. How do you access these components in a block or in a design specification or in a reaction? | Solution: Pseudocomponents generated automatically from an assay in Aspen Plus using the default naming convention (such as PC125) will not shown on the SEP2 block input forms. In fact they don't show in any block input form, including SEP and all reactors. This is by design, not a bug.
To generate the list of pseudoco... |
Problem Statement: How do I enter the tube bundle layout using the input forms or the graphical interface in Aspen Air Cooled Exchanger (Acol+)? | Solution: Aspen Air Cooled Exchanger (Acol+) permits symmetrical and non-symmetrical bundles to be entered, depending upon the data items that have been specified on the Input | Exchanger Geometry | Geometry Summary | Geometry tab.
Symmetrical bundles will have the same number of rows per pass, whereas non-symmetrical ... |
Problem Statement: How do I display cumulative heat load specification instead of specific enthalpy in properties? | Solution: The new cumulative heat load option will allow users to specify a cumulative heat load versus temperature profile for a stream rather than use specific enthalpy data. This option can be selected from the pull down list for the physical property package as shown below. When selected an additional input field w... |
Problem Statement: Which variable values are used for the dead_time block during the initialization by the solver? Dead_Time block uses the DELAY operator. | Solution: For initialization and steady state runs:
Delay does not apply, i.e. the equation y = DELAY x BY dt; is solved as if it was written y = x.
For dynamic runs:
The delay leaves the output (y) equal to the value of the converged initialization run at time 0 (x(0)) until the time is equal to the specified dead tim... |
Problem Statement: I am going to customise an Aspen Dynamics problem but I see unmatched variables when loading the Aspen Dynamics file in Aspen Custom Modeler. I have not made any changes to the file but I do not see this message when loading the same file in Aspen Dynamics.
Why does this happen and what does it mean?... | Solution: The results of the unchanged file will be exactly the same.
Slip is used in pressure relief calculations so in pipe, RCSTR, and the pressure relief models. It will only be something other than 1.0 if two phase, non-homogeneous flow is being modelled i.e. the vapour and liquid velocities are different.
It is a... |
Problem Statement: How do you embed a double quote in a string in Visual Basic/VBscript? | Solution: To embed in a string, you need to use double double quotes, e.g. Fmc(H2O) instead of Fmc(H2O).
Keywords:
References: None |
Problem Statement: Results for the condenser temperature differ between PetroFrac and RadFrac if the condenser is subcooled. | Solution: The results are correct, the difference in condenser temperature is due to a reporting convention.
In the attached example file, both the PetroFrac and the RadFrac blocks are set up in the same way, including the option both reflux and liquid distillate are subcooled.
The reported results for the column are t... |
Problem Statement: In the Decanter block, how is the specified separation efficiency of each compoent used? | Solution: In the decanter block, the specified component separation efficiency (Ei) is used as follows
x2i = Ei Ki x1i
Where E = specified component separation efficiency
K = equilibrium constant
x1 = liquid 1 mole fraction
x2 = liquid 2 mole fraction
i = component i
Ei is a fudge factor. It allows a user to manipulat... |
Problem Statement: For processes involving many unit operations it is sometimes desirable to specify different property methods for use in individual sections of the flowsheet. However, calculating the physical properties of the very same system by means of different property methods can lead to different results. This... | Solution: The reason for the discontinuity is that different property methods define different models and routes for a given property such as the enthalpy of the liquid phase. An activity coefficient model for example, typically calculates the liquid phase enthalpy (HL) in the following way
HL = HIG + DHV + DHVL
where
... |
Problem Statement: See the attached file for an example in Aspen Plus V7.3. The feed stream is made of water, NH3, HNO3 at 1 bar and 165C. This stream goes into a Flash2 block specified with a pressure drop of 0 and a heat duty of 0.
The simulation fails for both the feed stream enthalpy calculations and the block. W... | Solution: This is a known problem. If you have a vapor phase stream and try to solve as a vapor-liquid (V-L) problem using apparent components, the chemical equilibrium calculation code does not behave well. This is somewhat true for true-component approach also. For the feed stream, we suggest to change the valid phas... |
Problem Statement: Customer is unable to start the License manager on the PC. The NT Event Log will display an error stating Unable to find Host Lock. No error will be displayed on Windows 95/98. This typically happens after the License Manager has been configured and running properly for some period of time. | Solution: The SuperPro dongles has failed and will not allow the License Manager software to start properly. There were a faulty series of SuperPro dongles shipped to AspenTech last year, which may fail with no notice.
In order to minimize down time, perform the steps below:
Verify that the dongle is attached to the pa... |
Problem Statement: Is it possible to use a Design-Spec from Sequential Modular (SM) mode in Equation Orientated (EO) mode?
The Design Specification is executed in SM mode, and the result is used to initialize the problem in EO mode, but the target value is not kept when changes are made in the EO problem. Is it possibl... | Solution: Flowsheet design specifications are not supported in EO mode. Instead, a Spec Group must be used to make the equivalent variable specification changes in EO. Design specifications internal to a RadFrac block are supported and are carried over to EO; Spec Groups do not need to be created for them.
In EO mode,... |
Problem Statement: I am installing AES 10.2 Update 1. Do I need to install new license key codes for these products? | Solution: Any keys that worked for any of the AES 10.2 products will work for the AES 10.2 Update 1 products. This also means that Batch Plus 2.1 keys will work for Batch Plus 2.2, and Aspen B-JAC 10.2 keys will work for Aspen B-JAC 10.3 (this includes Aspen Hetran, Aspen Aerotran, and Aspen Teams).
Keywords: keycodes ... |
Problem Statement: The current AZ Vessel Tray datasheet template is not configured for the overspill function. | Solution: You can download from thisSolution document a similar version of this template which can be overspilled.
1. Copy the attached xls file in the Datasheets directory of the Workspace library (e.g. C:\AspenZyqadServer\Basic Engineering16.2\WorkspaceLibraries\Datasheets).
2. Copy the attached ztf and ztx in the Te... |
Problem Statement: How to use Microsoft Visual Studio debugger to debug user procedures or SAX function when these are called by ACM? | Solution: Note: The instructions are for Visual Studio 6.0 sp4. You need to install the service pack 4 (or above) of Visual Studio to fix a defect (see Microsoft Knowledge Base Article - 235434 FIX: Attach to Process List Is Empty, http://support.microsoft.com/default.aspx?scid=kb;en-us;235434).
The steps are:
build th... |
Problem Statement: When a SM (sequential modular) simulation is synchronised in Equation Orientated (EO) mode, there is no EO variable assigned for the component mole flow in a stream or block. What if you need to use this variable? | Solution: If you need to access a component mole flow to use in a Spec Group for example, then the component mole flow must first be calculated in a Calculator block, so that an EO variable is created for it. This example shows how to calculate a component mole flow in Equation Orientated (EO) mode.
For example in the ... |
Problem Statement: What property method is used for a pure water stream? Will the free water property method be used?
In PML, a block (or stream) with the single component of water would use the free water method to calculate water properties, regardless of the primary property method. This behavior is not the case for... | Solution: The primary property method is used for the stream properties unless free water is selected. If free water is selected, then the free water property method is used. See the attached simu1.bkp. Enthalpy balance and values remain identical either for water as the only non-zero component in three-component mixtu... |
Problem Statement: When using Aspen Air Cooled Exchanger, users are given freedom to define fouling inputs for both tubeside (process side) and outside (X-side), especially for tubeside where there are multiple options. | Solution: The default method to input fouling factors is to type in a constant value directly, on Input | problem Definition | Process Data | Tube Side Stream tab for tubeside, and Input | problem Definition | Process Data | Outside Stream tab for X-side.
Besides this method, tubeside fouling can also be defined by g... |
Problem Statement: How to get rid of Run time error 429: ActiveX component can't create object? | Solution: This error occurs if there is a problem with registry. Cleaning up the registry and re-register HTFS+ should solve the problem.
You will need administrative privileges for this.
Clean up the registry:
Find BjactRegClean.exe file. It is under XEQ folder inside HTFS+ folder. The default path is
C:\Program Files... |
Problem Statement: How do I change the workspace name? | Solution: Lets say if you want to rename a AZ162 workspace to AZTest.
- Open Workspace folder and change the folder name from AZ162 to AZTest.
- Open Workspace.lst file under workspace folder and also change the name here from AZ162 to AZTest
- Restart the broker.
Keywords: Rename workspace, change name
References: Non... |
Problem Statement: How to write to journal file from KB script | Solution: The following code can be used to write to the journal file called journal.log. This file is located in the workspace directory on the ABE server (e.g C:\AspenZyqadServer\Basic Engineering16.2\Workspaces\AZ162).
server.logInformation (strMessage)
server.logWarning (strMessage)
server.logError (strMessage)
Key... |
Problem Statement: Sometime, a user created in-house library to use with ACM, and does not want to see the default libraries. How can one remove the default libraries from the ACM Explorer? | Solution: One can remove the default libraries for the ACM Explorer (for example, Modeler.acml) using the command line option /Nodefaultlibraries in Command Prompt. For example, you use command line:
C:>C:\Program Files\AspenTech\Aspen Custom Modeler V7.1\acm.exe /Nodefaultlibraries
This option is first available i... |
Problem Statement: A simulation uses procedures calling external Fortran code. The external code is reading data from file(s). The dll is created successfully and all the procedures are correctly defined. The code has also been tested separately and is running properly.
When running the simulation the following error c... | Solution: Below is an identified cause. If it does not apply to your specific case, please contact Customer Support and include the files, if possible, to help us troubleshoot the new problem..
If the OPEN FORTRAN statement that is defined in the external code does not have the full path to where the file(s) containing... |
Problem Statement: What components of an air-cooled exchanger are included in a reported 'weight of exchanger' in Aspen Air Cooled Exchanger? | Solution: The weight parts such as support structure and fans are not included as the data on these are not available in Aspen Air Cooled Exchanger. The results of the calculations are in the form of two weights: Total weight of an empty tube bundle(s) and weight for tube bundle(S) filled with water.
The following de... |
Problem Statement: I get an error AirCooled (Input Error 524) the total outside stream mass flow must be input. What to do about this error? | Solution: The error message indicates that the air flow rate is missing. HYSYS displays the error after importing AirCooled / Aspen Air Cooled Exchanger / Acol+ file into HYSYS air cooler.
Double click on the air cooler. Go to Ratings tab and input the flow rate of air. If you don't know it and you have it in the AirCo... |
Problem Statement: What is the user privilege needed when importing a Simulation | Solution: The privilege Modify_Process_Data or TrespassDiscipline is needed when importing a simulation. The reason is that the Process discipline is assigned to attributes used by the simulator interface. If the user doesn't have one of these privileges, the simulator interface will not be able to import the simulatio... |
Problem Statement: How do I access simulation time in the model? | Solution: The model shown below illstrates the syntax.
Model TimeModel
TimeValue as time_;
x as realvariable;
TimeValue = time;
IF TimeValue < 0.01
THEN x = 1;
ELSE x = 2;
ENDIF
End
Keywords:
References: None |
Problem Statement: Why does CDI issue the error message The Index of your model is >1, for example if I try a CDI after a steady state run of an Aspen Dynamics simulation? | Solution: The CDI test for index>1 is different from what the Analyse tool does. So they can sometimes come to a different conclusion.
If your simulation has an index>1, this is detected in version 11.1 when you use the View, Specification Status. There is a button Check Legality/Index. This is not available in previou... |
Problem Statement: In Shell & Tube Exchanger, users can model a re-flux condenser by selecting 'Knockback reflux' as the Condenser type on Input | Problem Definition | Application Options | Application Options tab. In Air Cooled Exchanger (Acol+), there is no such option. Is it possible to model a reflux condenser with... | Solution: If you have an Air Cooled Exchanger case with tubeside condensing, and you want to model a re-flux air cooled condenser, you need to
? go to Input Exchanger Geometry | Unit Geometry | Unit Geometry tab
? Set 'Angle of outside flow' as an angle other than either 0 or 180 degrees ( 0 means t... |
Problem Statement: Sometimes reloading a saved simulation fails to converge, while it was working properly before. Why? | Solution: This is because Aspen Custom Modeler and Aspen Dynamics do not automatically preserve the value of the variables (unless you have manually assigned values). Typically this results in free variables not being preset to a value close to theSolution, hence causing convergence failure.
The robust way to prevent t... |
Problem Statement: What is the difference between Aspen Air Cooled Exchanger program calculation modes? | Solution: Design with fixed outside flow
In design mode, you specify the performance requirements in terms of inlet and outlet process conditions. The program searches for a satisfactory heat exchanger configuration by varying the tubes per bundle, the tube rows deep, the tube length, the tube passes, the bundles per b... |
Problem Statement: How does CDI scale the elements of the matrices? | Solution: The value of the elements of the matrices are scaled using the units of measurement selected in the User InterfaceI.
Example:
x as flow_mol (initial);
y as temperature (free);
u as flow_mol (fixed);
$x = -x + u;
y = x;
gives C(1,1) = 1 if y is in degree C and x in kmol/hr, C(1,1) is 1.8 if y is in ... |
Problem Statement: When PFD is submitted, all the symbols and connections turn gray and line width is not retained. Is there an option to turn this feature off? | Solution: If you will turn off the emphasize flag from view menu, it will turn off the rea-donly flag on display. When you will submit/check/issue PFD, the PFD will retain the color and line width
Keywords: None
References: None |
Problem Statement: How do I create a Restricted Case? | Solution: It can only be created from Explorer for particular object.
Restricted cases are created against a particular object.
You can create it from explorer by following steps below:
Select object for which you want to create a restricted case in explorer
On toolbar click on Case | Create | Restricted
It will ask yo... |
Problem Statement: Running a dynamic estimation - the simulation is very slow to run. | Solution: First of all make sure you review the advice outlined in this document:
Hints on using Optimization in Aspen Custom Modeler and Aspen Dynamics
You can improve performance further by choosing a communication interval with a value higher than the final dynamic simulation time for your experiments. This may spee... |
Problem Statement: In administrator tool, Drawing editor and Bridge privileges are missing and as a result existing drawing cannot be opened and new diagrams cannot be created. What is workaround? | Solution: This seems to be because of windows bug. A program was written as a diagnostic tool to understand the problem, that doesnt make any system changes. It does not update the registry but simply reads and prints. The process of printing out the contents of the category manager solves the problem on the machine. ... |
Problem Statement: Why is the setting plan for the air cooler missing in some cases? | Solution: In some cases, the setting plan will be unavailable as the Aspen Air Cooler provides a setting plan only for standard exchanger frame type air cooler. If an A or V frame air cooler is modelled, the setting plan for such type of exchanger will be missing.
Â
Keywords: Air Cooler, Setting Plan, Exchanger Type,... |
Problem Statement: Why don't I see the symbol relationships such as Equal, Parallel etc while defining symbol in graphic definer? | Solution: To enable a symbol to contain relationships, check the Tools | Maintain Relationships option in Graphic definer.
Keywords: Maintain Relationships , Parametric Symbols, Relationships
References: None |
Problem Statement: When comparing the results of the same case between Aspen ACOL 2004 (ACOL) and Aspen Acol+ (Acol+) the total X-side pressure drop and fan powers are quite different. | Solution: In Acol+ the correlation for the plenum pressure drop has been changed to that given in the book by Kroeger, D.G., Air Cooled Heat Exchangers and Cooling Towers New York, Begall House 1998. The previous method in ACOL, could in some circumstances, give a pressure loss in the plenum rather than a recovery (e.g... |
Problem Statement: What PDE methods are recommended for different modeling situations? | Solution: The following comments are meant as general advice - it is difficult to give advice for specific partial differential equation cases.
As you go from Central Finite Difference (FD) methods to Forward/Backward FDs to Biased FDs you get an increase in accuracy but a subsequent decrease in stability. The general ... |
Problem Statement: How to suppress the message boxes while ACM is under the control of a VB application? | Solution: To prevent the messages to be displayed while ACM runs with automation, you need to make ACM not visible, ie
objACM.application.visible = false
before you run the simulation (or before the conditions that trigger the message are encountered).
There is no other method. You can make ACM visible afterwards if yo... |
Problem Statement: How to modify the line styles in graphic definer? | Solution: If you want to add new line styles in drop down list of graphic definer, then you need to modify the 'style.sym' file which is located at C:\Program Files\AspenTech\Basic Engineering x.x\UserServices\bin\template\styles by default. The styles defined in this file are automatically loaded on the Graphic Define... |
Problem Statement: In Aspen Plus the results for vapor/liquid mixture can be displayed for liquid, vapour or total phase. Is it possible to display the results for the total phase in Aspen Custom Modeler (ACM). | Solution: Currently, there are no procedures available to evaluate the total phase properties and only phase=L and phase=V procedures are available.
To estimate the total phase properties, the phase fractions for the vapor and liquid phases should be reported first and subsequently, the total phase properties can be de... |
Problem Statement: Import from Aspen HYSYS is not retrieving certain pieces of data (such as mass flowrate), and other imported propertise (such as surface tension) appear wrong. How can this be fixed? | Solution: Cleaning up registry and then running the regcontrols.bat file should resolve this problem.
To clean up the system registry, run the bjacregclean.exe file located in HTFS+ | XEQ folder. The default path for this executable is:
C:\Program Files\AspenTech\Aspen HTFS+ 2006.5\XEQ
After double clicking on the ... |
Problem Statement: In Air Cooled Exchanger (Acol+), when using the 'Program will design tube layout based on input above', the number of tubes, rows, passes and tubes per row per pass are entered, and the program will determine the tube (row/pass) positions, where the X-side flow is perpendicular to the tubes, commonly... | Solution: The tube layout/pass arrangement can be set either entering input data to specify the bundle or using the interactive method, as described inSolution 125260.
When the 'input method' is used, on Input | Exchanger Geometry | Geometry Summary | Geometry tab there is a setting marked as 'Tube side to outside fl... |
Problem Statement: Can I copy variables from Aspen Air Cooled Exchanger and Aspen Shell & Tube Exchanger to Aspen Simulation Workbook (ASW)? | Solution: Starting with EDR V7.0 a new Copy/Paste functionality has been added to the Aspen Shell & Tube Exchanger, Aspen Air Cooled Exchanger, Aspen PlateFin, Aspen Fired Heater, and Aspen Shell & Tube Mechanical programs, allowing input and result variables shown in the EDR user interface to be copy/pasted into Aspen... |
Problem Statement: How can I estimate the power requirement for the electrical motor in an Air Cooled exchanger? | Solution: Aspen Air Cooled exchanger (formerly Aspen Acol+) reports the Absolute Power (winter/summer) on line 59 and 60 of the Results | Results Summary | Overall Summary | Aircooled Summary page. This Absolute Power is based on the combined efficiency of the fan and drive.
Therefore Electric motor power can be estima... |
Problem Statement: In HeatX with geometry data (rigorous calculation mode) you can specify the dimension of the tubes in different ways:
inner diameter and thickness
outer diameter and thickness
inner and outer diameters
I have specified the inner diameter to 20 mm, and the tickness to 2 mm. However I find that if I sp... | Solution: . You could rewrite it to say:
Problem Description
Aspen Plus says that 1+1 = 2, but perhaps 1 + 1 = 3.1416?
Solution
In fact 1 + 1 really does = 2
I hate to have to use the Rejected status, but here goes - I'm sure you understand....
Ben
Creation Date: 16-Mar-2001 08:42AM
Applicable Version(s):
any
Keyword... |
Problem Statement: How to find the position of the maximum or minimum element in an array? | Solution: If you need to find the location of the maximum after run the simulation run has completed, a script is probably the bestSolution. You could use a similar technique to the Fortran example below.
For run-time, oneSolution is to use a procedure. See the model below, which features an array of temperatures. The ... |
Problem Statement: When I run HTFS+ 2006.5, I see the Error Message, Run-time error '430': Class does not support Automation or does not support expected interface. | Solution: This error message may occur if you have multiple version of HTFS+ installed on your machine, where after running an older version and then trying to run HTFS+ 2006.5 the following error occurs.
The work around is to
1. From the Aspen HTFS+2006.5 shortcut run the Version Control Utility
2. In the ... |
Problem Statement: Can we run an Aspen Custom Modeler (ACM) model with free inlet port variables in Aspen Plus or HYSYS? | Solution: When an ACM model is run in Aspen Plus or HYSYS, the inlet port variables will be fixed and should stay fixed. There is no backwards calculation of inlet stream variables; the information flow is one way. The model should be developed and run in ACM with fixed inlet port specifications.
Key Words
ACM Model, F... |
Problem Statement: How to perform a steady state optimization in Aspen Custom Modeler (ACM). | Solution: The first step is to make sure that the steady state ACM file runs with no errors. It is a good idea to carry out a sensitivity analysis of the ACM model by varying the values for the fixed variables at the inlet of the model and observe the convergence.
In the attached file, the methanol reactor model, the i... |
Problem Statement: You have a vector in Aspen Custom Modeler that is indexed by a String Set, like:
1. a vector containing component-dependent quantities like molar fraction (indexed by ComponentList)
2. a vector of quantities dependent on the name of the connections for a multiport (indexed by ConnectionLi... | Solution: This is by design. The same problem occurs when ACM is interfacing with the Aspen Plus property layer.
OneSolution is to copy the arrays of molar fractions to a temporary storage area, and reorder them as appropriate before calling the Aspen Plus property monitor. Another vector copy and reordering has to tak... |
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