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Problem Statement: Why aren't Fortran variables in Design-Specs updated from one iteration to the next? | Solution: All the DEFINED variables in DESIGN-SPEC are READ-ONLY variables and the values printed in result form are values before executing any Fortran code . They are NOT updated even if it get changed in the Fortran code. In a design-spec convergence loop, the VARY variable is the only variable that is being manipulated to meet the SPEC.
The initial and final value refers to the value of DEFINED variable at the 1st and last spec calculation of the last spec loop (if nested inside other convergence loop). They are all values before executing Fortran code.
In V7.2, the help has been modified:
Design Spec Input sheet:
Added All these variables are read-only, and will not be changed by the Design-Spec itself after You can sample any number of flowsheet variables.
Design Spec Fortran sheet:
Note: All defined variables in Design-Specs are read only. If you change the value of one of these variables, that change lasts only to the end of execution of the Fortran code on this sheet, and does not change the Aspen Plus variable it is associated with.
Keywords: None
References: None |
Problem Statement: Are there any copper smelting examples for Aspen Plus? | Solution: This is an example based on the Noranda process white paper entitled Process modelling in metallurgy: applications of ASPEN PLUS to metallurgical processes The paper was presented at the 2nd International symposium on Computer Software in Chemical and Extractive Metallurgy in Quebec City, in 1993. The paper was authored by Paul Talley, Suphat Watanasiri, Selim Anavi and C.W. Bale.
Please also seeSolution 113786 which covers the topic of melting pure copper and how Aspen Plus calculates solid-liquid equilibrium for metals.
Keywords: Rgibbs, smelting, copper, Noranda process
References: None |
Problem Statement: Is it possible to use more than one property specification in one simulation?
Can I use a different Property Method or a different Chemistry ID in a particular block? | Solution: There are several ways you can use different Property Methods in one simulation. Similarly, the Henry component ID, the Chemistry ID and electrolyte simulation approach, the Free-water phase properties and water solubility method can also be changed on these levels with the exception of in an RGibbs where only the Property Method can be changed for different phases.
Feed streams inherit properties from their downstream blocks, while all other streams use the properties from their upstream blocks.
1. Block Level
You can use different property methods for different individual blocks. Go to a block's Block Options | Property Method sheet and choose the method you want from the drop down list.
2. Hierarchy Level
You can change the property method of an entire Hierarchy. This is one way to change property method of an entire section of a flowsheet. To make the change, go to the Hierarchy block's Properties | Specifications form.
3. Flowsheet Section
You can use different property methods in different flowsheet sections. To do that go to the Properties | Specifications | Flowsheet Section sheet. Choose a flowsheet section ID from the drop down list. Select the property method in the appropriate field(s).
4. Distillation Column Models
In the rigorous distillation column models (RadFrac, MultiFrac and PetroFrac), you can use different property methods in different sections of the column. Open the column folder in data browser and on the Properties form, choose starting and ending stages of a section and then choose a property method for each section. You can create multiple sections to use multiple property methods.
5. RGibbs
RGibbs allows you to use multiple property methods for different phases when you select Define phases in which product appears. The option is on the RGibbs block's Setup | Products sheet.
When you use different property methods in one simulation you may encounter discontinuous properties. The followingSolution document gives more details.
http://support.aspentech.com/webteamasp/KB.asp?ID=104120
Keywords: Different, property method, fluid package, more than one, block, section, hierarchy
References: None |
Problem Statement: Is there any way to report the chemical oxygen demand and biological oxygen demand using a property-set in Aspen Plus? | Solution: There is no built-in property-set for chemical or biological oxygen demands. Aspen Plus has a prop-set called COMB-O2 which is the amount (mole or mass) of oxygen needed to completely combust a stream. It is possible to write your own user prop-set property to calculate the chemical or biological oxygen demand.
However, in 2006.5, new prop-set properties were added to calculate chemical and biological oxygen demand.
BOD = Biochemical oxygen demand for pure component.
BODMX = Biochemical oxygen demand for mixture.
COD = Chemical oxygen demand for pure component.
CODMX = Chemical oxygen demand for a mixture.
Chemical Oxygen Demand (COD) is equal to the theoretical oxygen demand. The following equation is used to calculate the theoretical oxygen demand of a substance.
The oxygen demand of a substance CcHhClclNnNanaOoPpSs of molecular weight MW is given by
This calculation implies that
C is mineralized to CO2
H is mineralized to H2O
P is mineralized to P2O5
Na is mineralized to Na2O
Halogen is eliminated as hydrogen halide
Nitrogen is eliminated as ammonia
Biological Oxygen Demand (BOD) is equal to 60% of the Chemical Oxygen Demand (COD).
Keywords: None
References: None |
Problem Statement: Will a dual core machine help when running Aspen Plus? | Solution: This information about dual CPUs came from the development team:
The Aspen Plus Graphical User Interface (GUI) is multi-threaded. So it can potentially use more than one core. The Aspen Plus Engine is mostly single-threaded so it can use only one core.
When GUI/Engine are both running (typical), they can use two cores.
You get better response with other applications when Aspen Plus is running (assuming that disk does not become the bottleneck).
The price difference between single and dual core CPUs is now so small, it probably won't make sense to buy new PCs with single core CPU.
Keywords: None
References: None |
Problem Statement: How can one retrieve the UNIFAC parameters such as GMUFQ, GMUFR of known functional groups from Aspen Plus database? | Solution: The UNIFAC parameters can be directly retrieved from databank only when the UNIFAC property method is selected as the Base method in the Properties | Specifications | Global form. Enter the required databank components on the Components | Specifications | Selection tab, click on Review button on the same page or from menu Tools -> click Retrieve Parameter Results. The UNIFAC parameters will appear under Properties |Parameters Results UNIFAC Group and/or UNIFAC Group Binary respectively.
More often than not, the UNIFAC parameters are used in Estimation concurrently with other property methods. As such, the Retrieve method will work unless one has entered a dummy component and some dummy parameters first.Solution ID 114200 (How does one enter a new UNIFAC group in Aspen Plus and what parameters are required?) provides an example file and detailed instructions on how to set up dummy groups.
The attached example to thisSolution is meant to illustrate such a situation.
Keep a text copy of the information by generating a report for the simulation from menu View -> click Report, Simulation, Ok.
Keywords: UNIFAC, GMUFQ, GMUFR, GMUFPQ, GMUFPR, GMUFLQ, GMUFLR, GMUFDQ, GMUFDR, GMUFB, retrieve
References: None |
Problem Statement: Crystallizer Example in Aspen Plus
The attached file was created in Aspen Plus 12.1 and will run in 12.1 and higher. | Solution: The Aspen Plus Crystallizer block can be used to represent a mixed-suspension mixed-product removal crystallizer. The product magma density and residence time are calculated from an overall material and energy balance and phase equilibrium. This model can also calculate the crystal product size distribution based on the crystal nucleation rate, size dependent growth-rate and equipment parameters.
Three approaches are available under saturation calculation method in Crystallizer block
Solubility method: Identify the crystallizing component as solid product on the Setup Crystallization sheet. Enter solubility data on the Setup Solubility sheet. This data applies to the reactant species in the mixed substream.
Chemistry method: Create a new Chemistry on the Reactions Chemistry object manager. Enter the crystallization as a salt reaction on the Reactions | Chemistry | Stoichiometry sheet. On the Block Options | Properties sheet of the crystallizer, enter the Chemistry ID and select True Species for Simulation Approach. You must specify the crystallizing component as a Salt Component ID on the Setup | Specifications sheet.
User Subroutine method: Identify the crystallizing component on the Setup | Crystallization sheet and the solubility data basis and solvent ID on the Setup | Solubility sheet. Specify a user subroutine to calculate saturation concentration or crystallizer yield on the Advanced | User Subroutine sheet.
In general, when using the Solubility method, you should blank out the Chemistry ID field on the Block Options | Properties sheet. If you specify chemistry when using the Solubility method, the chemistry must not contain the crystallizing component.
Aspen Plus calculates the crystal size distribution statistics once you select the Calculate PSD from Growth Kinetics option on the PSD | PSD sheet.
This example contains a crystallizer block to illustrate the first and second approaches with Particle Size Distribution consideration (PSD) & without Particle Size Distribution consideration.
Keywords: Crystallizer, PSD, solubility
References: None |
Problem Statement: When you define a Component Group and use it in tear convergence calculations, what happens to the components not in the group? | Solution: Direct substitution will be used for those components not in the group. One can set up Calculator blocks to verify the values of the variables before and after a convergence block.
An example is attached. The example will run in V10 and higher.
In this example Acetone is specified in the Component Group CG-1:
The stream TEAR is the tear stream:
In Calculator AFT-H1, executes after Block H1 and reports the Components Mole Flows in SI units kg/sec. Component 1 is Acetone, Component 2 is Water, and Methanol is Component 3. In Calculator AFT-C1, executes after Convergence C-1 and reports the compositions. After the Convergence block, only the Component 1 Acetone is changed.
In the Control Panel, you will see the values reported as the simulation converges.
.
.
.
Block: H1 Model: HEATX
Calculator Block AFT-H1
AFTER H1 BLOCK
1088.3149 1
12610.4089 2
551.2761 3
> Loop C-1 Method: WEGSTEIN Iteration 2
Converging tear streams: TEAR
NEW X G(X) X ERR/TOL
TOTAL MOLEFLOW (1) 14259. 14250. 10000. 4250.0
ACETONE MOLEFLOW(2) 1096.9 1088.3 1000.0 883.15
PRESSURE (2) 0.11514E-02 0.11514E-02 0.12893E-02 -1069.5
MASS ENTHALPY (2) -0.12875 -0.12875 -0.12337 -435.96
4 vars not converged, Max Err/Tol 0.42500E+04
Calculator Block AFT-C1
AFTER CONVERGENCE BLOCK
1096.8700 1
12610.4089 2
551.2761 3
Block: C1 Model: RADFRAC
Convergence iterations:
OL ML IL Err/Tol
1 1 5 83.391
2 1 2 7.2289
3 1 3 0.61287
Block: B1 Model: FSPLIT
Block: B2 Model: MIXER
Block: H1 Model: HEATX
Calculator Block AFT-H1
AFTER H1 BLOCK
1092.6125 1
14415.4254 2
551.8479 3
> Loop C-1 Method: WEGSTEIN Iteration 3
Converging tear streams: TEAR
NEW X G(X) X ERR/TOL
TOTAL MOLEFLOW (1) 16060. 16060. 14259. 1263.3
ACETONE MOLEFLOW(2) 1092.4 1092.6 1096.9 -38.815
MASS ENTHALPY (2) -0.13277 -0.13105 -0.12875 -178.67
3 vars not converged, Max Err/Tol 0.12633E+04
Calculator Block AFT-C1
AFTER CONVERGENCE BLOCK
1092.4149 1
14415.4254 2
551.8479 3
Block: C1 Model: RADFRAC
Convergence iterations:
OL ML IL Err/Tol
1 1 5 19.228
2 1 2 1.4968
3 1 3 0.87715E-01
Block: B1 Model: FSPLIT
Block: B2 Model: MIXER
Block: H1 Model: HEATX
Calculator Block AFT-H1
AFTER H1 BLOCK
1074.6714 1
15208.9746 2
541.7216 3
> Loop C-1 Method: WEGSTEIN Iteration 4
Converging tear streams: TEAR
NEW X G(X) X ERR/TOL
TOTAL MOLEFLOW (1) 16825. 16825. 16060. 476.77
ACETONE MOLEFLOW(2) 1074.7 1074.7 1092.4 -162.42
MASS ENTHALPY (2) -0.13207 -0.13228 -0.13277 36.319
3 vars not converged, Max Err/Tol 0.47677E+03
Calculator Block AFT-C1
AFTER CONVERGENCE BLOCK
1074.6714 1
15208.9746 2
541.7216 3
Block: C1 Model: RADFRAC
Convergence iterations:
OL ML IL Err/Tol
1 1 5 19.904
2 1 2 1.5075
3 1 3 0.67606E-01
Block: B1 Model: FSPLIT
Block: B2 Model: MIXER
Block: H1 Model: HEATX
Calculator Block AFT-H1
AFTER H1 BLOCK
1090.1720 1
15510.9929 2
549.6163 3
> Loop C-1 Method: WEGSTEIN Iteration 5
Converging tear streams: TEAR
NEW X G(X) X ERR/TOL
TOTAL MOLEFLOW (1) 17151. 17151. 16825. 193.41
ACETONE MOLEFLOW(2) 1090.2 1090.2 1074.7 144.24
MASS ENTHALPY (2) -0.13234 -0.13234 -0.13207 -20.650
3 vars not converged, Max Err/Tol 0.19341E+03
Calculator Block AFT-C1
AFTER CONVERGENCE BLOCK
1090.1720 1
15510.9929 2
549.6163 3
Block: C1 Model: RADFRAC
Convergence iterations:
OL ML IL Err/Tol
1 1 3 0.25061
Block: B1 Model: FSPLIT
Block: B2 Model: MIXER
Block: H1 Model: HEATX
Calculator Block AFT-H1
AFTER H1 BLOCK
1089.3161 1
15650.5739 2
549.1920 3
> Loop C-1 Method: WEGSTEIN Iteration 6
Converging tear streams: TEAR
NEW X G(X) X ERR/TOL
TOTAL MOLEFLOW (1) 17289. 17289. 17151. 80.638
ACETONE MOLEFLOW(2) 1089.3 1089.3 1090.2 -7.8518
MASS ENTHALPY (2) -0.13276 -0.13251 -0.13234 -12.420
3 vars not converged, Max Err/Tol 0.80638E+02
Calculator Block AFT-C1
AFTER CONVERGENCE BLOCK
1089.3161 1
15650.5739 2
549.1920 3
Block: C1 Model: RADFRAC
Convergence iterations:
OL ML IL Err/Tol
1 1 4 0.61022
Block: B1 Model: FSPLIT
Block: B2 Model: MIXER
Block: H1 Model: HEATX
Calculator Block AFT-H1
AFTER H1 BLOCK
1086.3798 1
15713.8723 2
547.6078 3
> Loop C-1 Method: WEGSTEIN Iteration 7
Converging tear streams: TEAR
NEW X G(X) X ERR/TOL
TOTAL MOLEFLOW (1) 17348. 17348. 17289. 33.997
ACETONE MOLEFLOW(2) 1086.4 1086.4 1089.3 -26.956
MASS ENTHALPY (2) -0.13257 -0.13263 -0.13276 9.8820
3 vars not converged, Max Err/Tol 0.33997E+02
Calculator Block AFT-C1
AFTER CONVERGENCE BLOCK
1086.3798 1
15713.8723 2
547.6078 3
.
.
.
Keywords: None
References: None |
Problem Statement: How to view composition profiles in mass basis in a PetroFrac column? | Solution: The composition profile in PetroFrac is on a mole basis. PetroFrac's profile does not have a drop down list to change the composition basis. However, you can create a prop-set with MASSFRAC property and specify liquid and/or vapor phases as qualifier. Then, this prop-set can be added on the Reports | Properties sheet. After running the file, the Mass fraction table will show up in the column's Profile | Properties sheet.
Keywords: Petrofrac, column, profile, mass fraction, composition, mass, basis
References: None |
Problem Statement: Visual C++ 2005 express from the Microsoft web site does not install properly. This results in a link failure. | Solution: There can be problems installing Visual C++ 2005 express from the Microsoft web site directly possibly due to firewall protections. When this happens, you have to do manual installation by downloading CD images from http://msdn2.microsoft.com/en-us/express/aa718401.aspx
You can burn/mount the CD image and install from there.
Keywords: Fortran compile link
References: None |
Problem Statement: Calculators or other user models that use Min and Max functions can lead to | Solution: failure in Equation Oriented (EO) mode. You may see this message during the EOSolution
Rank Deficient Jacobian
Sometimes theSolution file (ATSLV) may indicate which equation is singular and may point directly to the equation with the Min or Max function to verify the problem.
The Min and Max function work with some specifications, but not others. However, it is best to eliminate conventional Min and Max functions to make the model more robust.
Solution
Rather than use the conventional Min and Max functions, use these smoothing functions:
DMIN = 0.50D0 * ( X1+X2 - DSQRT( (X1-X2)**2 + TOL**2 ) )
DMAX = 0.50D0 * ( X1+X2 + DSQRT( (X1-X2)**2 + TOL**2 ) )
Where TOL is the smoothing tolerance. This will create some inaccuracy in theSolution near the point where X1 and X2 are equal, but the smoothing prevents the loss of derivatives and thus the singularities.
The equations must be applied N-1 times when there are N inputs.
Keywords: EO, equation oriented, discontinuity, eo rank deficient jacobian error
References: None |
Problem Statement: How To Convert Aspen Plus 2004.x input file to Aspen Plus 11.1 readable file. | Solution: First create an INP file by saving your Aspen 13.x flow sheet as input file and do the
following modifications within that file:
1) Change the Header from 13.x to 11.1 within the file INP file
2) Change Data Bank from 13.x to 11.1 within the saved file
3) Change Aspen Dynamics to DynaPlus If Dynamic is installed on the system where the
INP file was created.
4) Comment out EO Option within the file INP file if it exist.
Keywords: Conversion
Aspen Plus 2004.
AspenOne
Aspen Plus11.1
References: None |
Problem Statement: How do I add heat to splitter (FSplit) or mixer (Mixer) block? | Solution: Aspen Plus does not allow you to add more than one type of stream to feed a mixer or a splitter.
This means that a Heat stream cannot be added to a material stream mixer or splitter.
However, it is possible to model this situation using Heater blocks in conjunction with material splitters and mixers. In fact, a Heater can be used instead of a Mixer since a Heater allows both Material streams and Heat streams as feeds.
Keywords: Splitter, mixer, heat, material, add
References: None |
Problem Statement: How do you get the new NIST databank in Aspen Plus? | Solution: The NIST06 database is a new database for the 2006 release of Aspen Plus and Aspen Properties. There is no additional charge for this database. The database is available in the new Enterprise Database architecture only; it is not available in the legacy DFMS format. The NIST06 database contains a single databank called NIST-TRC.
To change from the legacy to the Aspen Properties Enterprise Database (APED) in Aspen Plus, go to Start -> AspenTech -> Aspen Engineering Suite -> Aspen Plus 2006 -> Aspen Properties Database Selector. Then select Aspen Properties Enterprise Database. Now the NIST databank will be available on the Components | Specifications | Enterprise Database sheet.
The new NIST06 database is a major enhancement to our library of physical property parameters for pure components. Approximately 13,000 new compounds (mostly organic) have been introduced, in addition to the approximately 2000 compounds already available in the main pure component databank (such as PURE20).
The new database is provided under an agreement with the National Institute of Standards and Technology's (NIST) Standard
Keywords: NIST06
References: Data Program (SRDP). The property parameters and the experimental data used were collected and evaluated by the Thermodynamics Research Center (TRC) using the NIST ThermoData Engine (TDE) and the NIST/TRC Source Data Archival System for experimental thermophysical and thermochemical property data. The NIST/TRC Source data is one of the world's most comprehensive collections of such data. The NIST06 database includes the following parameters:
Parameter
Parameter Name Description
CPIALEE
TDE Ali-Lee ideal gas Cp
CPITMLPO
ThermoML Polynomials for ideal gas Cp
CPLTDECS
TDE equation for liquid Cp
CPLTMLPO
ThermoML polynomials for liquid Cp
CPSTMLPO
ThermoML polynomials for solid Cp
DELTA
Solubility parameter @ 25 C
DHVLTDEW
TDE Watson equation for heat of vaporization
DNLRACK
TDE Rackett parameters for liquid molar density
FREEZEPT
Freeze point temperature
HFUS
Heat of fusion
KLTMLPO
ThermoML polynomials for liquid thermal conductivity
KVTMLPO
ThermoML polynomials for vapor thermal conductivity
MULNVE
TDE equation for liquid viscosity
MULPPDS9
PPDS9 equation for liquid viscosity
MUP
Dipole moment
MUVTMLPO
ThermoML polynomials for vapor viscosity
MW
Molecular weight
OMEGA
Pitzer acentric factor
PSTDEPOL
TDE polynomials for solid vapor pressure
PC
Critical pressure
SG
Specific gravity
SIGISTE
TDE expansion for liquid-gas surface tension
SIGPDS14
PPDS14 equation for liquid-gas surface tension
SIGTDEW
TDE Watson equation for liquid-gas surface tension
TB
Normal boiling point
TC
Critical temperature
THRSWT
Thermodynamic property sub-model selector
TPT
Triple point temperature
TRNSWT
Transport property sub-model selector
VC
Critical volume
VLSTD
API standard liquid molar volume
WAGNER25
TDE Wagner 25 liquid vapor pressure
In the future, this databank will be expanded to include:
- Raw pure component data
- Binary data
- Parameter generation |
Problem Statement: You can easily copy the normal Stream Summary to Excel by clicking in the top-left cell of the Stream Summary grid to copy the information to the clipboard and then paste into Excel. However, this procedure does not work for a Custom Stream Summary. How do you export a Custom Stream Summary to other programs such as Excel? | Solution: To export or copy a Custom Stream Summary to Excel, click on the tab for the Custom Stream Summary sheet that you want to copy. From the Edit menu, click on Select All. Then, from the Edit menu, click on Copy. You can now paste the stream summary into Excel by clicking in a cell in Excel, and selecting Paste.
Keywords: Custom Stream Summary
Excel
Stream results
References: None |
Problem Statement: How do you link Aspen Plus user routines and a IMSL library into an Aspen Plus model? | Solution: Some versions of the Intel Fortran come with the VNI/IMSL library. The standard Aspen Plus compiler configuration does not support the use of IMSL library.
In order to use IMSL in Aspen Plus runs, you need to make changes as described here. Note that because of frequent compiler/library changes, you may have to follow the spirit of the steps described here (replace directory paths as appropriate, etc.). We want to thank our customer Kunle Ogunde from DuPont for sharing some of the information here.
Modify Compilers.cfg to include IMSL related information
Aspen Plus uses the information in Compilers.cfg to set up the compiler environment for compilation and linking for many C/C++/Fortran compiler combinations.
Note: Edit Compilers.cfg with a text editor (like NotePad) not a word processor (like Word). Be sure not to introduce any extra line breaks or spaces.
To use the IMSL library, you need to:
1. Locate Compilers.cfg and make a backup. The file is located in
C:\Program Files\AspenTech\AprSystem <version>\Engine\Xeq
2. Find the appropriate compiler section in Compilers.cfg and make the changes.
3. Alter FNL_DIR if you are using any IMSL library other than version 6.
4. Close and reopen any Aspen Plus Simulation Engine windows.
The changes required are shown in red in the following example which assumes you are using the IVF10_VS9 configuration.
Begin IVF10_VS9 Intel Fortran 10.x and Microsoft Visual Studio 2008
IFDir=HKEY_LOCAL_MACHINE(SOFTWARE\Intel\Compilers\Fortran\10#.###\IA32\ProductDir)
VSDir=HKEY_LOCAL_MACHINE(SOFTWARE\Microsoft\VisualStudio\9.0\InstallDir)\..\..
SDKDir=HKEY_LOCAL_MACHINE(SOFTWARE\Microsoft\Microsoft SDKs\Windows\CurrentInstallFolder)
INCLUDE=$(IFDir)\Include;$(VSDir)\vc\atlmfc\include;$(VSDir)\vc\include;$(SDKDir)\include
LIB=$(IFDir)\lib;$(VSDir)\vc\atlmfc\lib;$(VSDir)\vc\lib;$(SDKDir)\lib
PATH=$(IFDir)\bin;$(VSDir)\Common7\IDE;$(VSDir)\vc\bin;$(VSDir)\Common7\Tools;$(SDKDir)\bin;$(PATH)
#
# Start of IMSL changes - non MPI
FNL_DIR=C:\Program Files\VNI\imsl\fnl600
INCLUDE=$(FNL_DIR)\IA32\INCLUDE\dll;$(INCLUDE)
LIB=$(FNL_DIR)\IA32\LIB;$(LIB)
PATH=$(FNL_DIR)\IA32\LIB;$(PATH)
# End of IMSL changes - non MPI
#
USE_COMPAQ_FORTRAN=
IFDir=
VSDir=
End
SDKDir=
Another version of the IMSL library installs in a folder named CTT6.0 and has
a different folder structure. This version needs changes to this section of
Compilers.cfg like the following:
FNL_DIR=C:\Program Files\VNI\CTT6.0
INCLUDE=$(FNL_DIR)\include\IA32;$(INCLUDE)
LIB=$(FNL_DIR)\lib\IA32;$(LIB)
PATH=$(FNL_DIR)\lib\IA32;$(PATH)
Modify Fortran code that interfaces with IMSL
The AspenPlus compilation script, aspcomp.bat, uses the following compiler options:
/iface:cvf /MD /Qsave
The /iface:cvf option specifies the Compaq-Fortran-compatible calling convention.
When you mix object (.obj or .lib) files created using different calling conventions, you must tell the compiler to use the right calling conventions. This is done by adding CDEC$ ATTRIBUTES directives in the Fortran code.
Here is an example of how to properly specify the calling convention when dealing with IMSL routines. This routine itself is compiled with aspcomp.bat.
SUBROUTINE MYSUB(N, X, ...)
IMPLICIT NONE
c
c Tells the compiler that the IMSL routine DNEQNF we want to
c call is compiled with default calling convention
c
cDEC$ ATTRIBUTES DEFAULT :: DNEQNF
c
c Tells the compiler that the EXTERNAL EQNS to be called
c by IMSL is compiled with default calling convention
c
cDEC$ ATTRIBUTES DEFAULT :: EQNS
INTEGER N
REAL*8 X(N), ....
EXTERNAL EQNS
......
c
c Calling IMSL DNEQNF routine and pass our EQNS callback
c routine as EXTERNAL
c
CALL DNEQNF(EQNS, ERREL, N, ITMAX, XGUESS, X, FNORM)
......
RETURN
END
SUBROUTINE EQNS (X, F, N)
IMPLICIT NONE
c
c Tells the compiler to compile EQNS with default calling
c convention because it will be called by IMSL. Note that
C the routine that passes EQNS as EXTERNAL to IMSL routine
C also need the same declaration.
c
cDEC$ ATTRIBUTES DEFAULT :: EQNS
INTEGER N
REAL*8 X(N), F(N)
.......
RETURN
END
In the example above:
If you forget to declare DNEQNF, you will get
missing routine _DNEQNF@28
in the linker output (.ld) file, or in general _ROUTINE@nn where ROUTINE is the IMSL routine missing a declaration and nn is 4 times the number of arguments.
If you forget to declare EQNS (in TWO places), you won't get a linker error but the program will crash when it runs.
Add IMSL libraries to the dlopt file for linking
To use user routines that use the IMSL library in Aspen Plus, or to use asplink to build a DLL that uses the IMSL library, you need to specify IMSL libraries in a dlopt file.
We don't have Intel Fortran with IMSL library and the IMSL document also lacks the information for using IMSL with other products. Our customer Kunle Ogunde from DuPont kindly provided us the following information.
For simple situations, try adding the following lines in the dlopt file:
%FNL_DIR%\IA32\lib\imsl.lib
%FNL_DIR%\IA32\lib\IMSLBLAS.LIB
%FNL_DIR%\IA32\lib\IMSLS_ERR.LIB
%FNL_DIR%\IA32\lib\libguide40.lib
/NODEFAULTLIB:libcmt.lib
If the short list is insufficient, try the following list:
%FNL_DIR%\IA32\lib\imsl.lib
%FNL_DIR%\IA32\lib\IMSLSUPERLU.LIB
%FNL_DIR%\IA32\lib\IMSLSCALAR.LIB
%FNL_DIR%\IA32\lib\IMSLBLAS.LIB
%FNL_DIR%\IA32\lib\IMSLS_ERR.LIB
%FNL_DIR%\IA32\lib\IMSLMPISTUB.LIB
%FNL_DIR%\IA32\lib\MKL_IA32.lib
%FNL_DIR%\IA32\lib\imslp_err.lib
%FNL_DIR%\IA32\lib\imslsparsestub.lib
%FNL_DIR%\IA32\lib\libguide40.lib
%FNL_DIR%\IA32\lib\mkl_blacs_mpich2.lib
%FNL_DIR%\IA32\lib\mkl_c.lib
%FNL_DIR%\IA32\lib\mkl_scalapack.lib
/NODEFAULTLIB:libcmt.lib
You may have to do some experiments if you are still getting missing IMSL routines in the linker output (.ld) file.
Notes on using asplink.bat to build a DLL that uses the IMSL library
Type asplink help for asplink syntax.
The option to specify a dlopt file with asplink is dlopt=dlopt_file (Note: Not /dlopt=...).
Typical commands to build MyDll.lib/.dll from myfile1.f and myfile2.f with additional libraries specified in MyDll.opt are as follows
aspcomp myfile1.f
aspcomp myfile2.f
asplink MyDll dlopt=MyDll.opt
del myfile1.obj
del myfile2.obj
These commands should be executed from an Aspen Plus Simulation Engine Window.
Be sure to delete loose .obj files because loose .obj files are automatically linked into runid.dll.
If you use object files that call IMSL libraries in an Aspen Plus simulation, then you need to include IMSL libraries in the dlopt file for the Aspen Plus simulation.
If you build MyDll.dll/.lib in advance, and use this prebuilt DLL in your Aspen Plus simulation, then you do not need to include IMSL libraries in the dlopt file for the Aspen Plus simulation, but you do need to include MyDll.lib in this dlopt file.
Keywords: None
References: None |
Problem Statement: Hetran imported wrong data under process conditions. I want to modify it but all the fields are grayed out. How can I modifiy the process conditions or any other value?
Hetran process conditions are grayed out. How can I modify them? | Solution: Checking the Enable Run box will allow you to modify values in this situation. The red oval shape in the picture below shows you where the option is. Please visitSolution # 108227 to know more about how to use Hetran.
Keywords: Enable Run, grayed, grayed out, modify, hetran, process,
References: None |
Problem Statement: Why is the distillate temperature in the stream summary not equal to that in the RadFrac Profiles? | Solution: When efficiencies are used, the vapor leaving a tray is no longer in equilibrium with the liquid from that stage, i.e. it is not at its dew point condition. Therefore, the flash calculation done for the stream summary will calculate a different temperature (the dew point for a vapor, bubble point for a liquid) than the one calculated by RadFrac.
The correct temperature in this case is the one reported in the RadFrac column profiles since this is the temperature which will be consistent with the efficiencies specified by the user. In order to remove the inconsistency in the stream summary, turn off the product stream flash calculation on the RadFrac/Convergence/Advanced form in the Eff-flash field. Note that in recent versions of Aspen Plus, this field defaults to No meaning that the product streams are not flashed if the efficiencies have been specified in the RadFrac block.
Keywords: dew point, bubble point, Murphree, Vaporization, condensor, reboiler
References: None |
Problem Statement: The property Beta which can be defined in a property set is the molar fraction of the liquid that is in the first liquid (L1) phase; hence, its value can be used to determine if two liquid phases are present. The property set can be reported for streams, for stages in a column, in an Analysis table, etc. Does one need to use the a vapor-liquid-liquid flash to get the correct value of beta? | Solution: Vapor-liquid-liquid flash needs to be specified, or else Beta will always have a value of 1. Beta is independent of the algorithm used in columns such as RadFrac. There, it calls a routine based on gibbs free energy minimization during the report pass that determines if the simulation will have two liquid phases.
Keywords: prop-set
analysis
VLL
3-phase
References: None |
Problem Statement: Is it possible to use another program to read an XML file exported from Aspen Plus? | Solution: The attached .zip file contains a demo program written in C for reading an XML file exported from Aspen Plus. Unzip it, then open the .sln file with Dev Studio 2008. Hit the F5 button to build and run it. When the program starts, open an XML file, then choose an object in the combo box to see its variables.
Keywords: None
References: None |
Problem Statement: What are the switches for apwn.exe?
I found out some of the switches by trial and error:
-b *.apw ---> generates *.bkp
-i *.inp ---> opens an input file
-p *.apw ---> prints the top level flowsheet
-r *.bkp ---> generates *.apw
I am sure there some more options. | Solution: To find all of the options type apwn -help from Start | Run.
(In Aspen Plus 12.1, the help command does not give the following list, but the switches themselves work work.)
Usage: apwn.exe [-<Switch] [<filename>]
<Actions>
-a Open Archive file (.bkp)
-i Open Input file (.inp)
-proII Open Pro/II Input file (.inp)
-b Generate Archive file from Document file (.apw)
-r Generate Document file from Archive file
-input Generate Input file from Archive or Document file
-pt Print To...
-p Print
-genpdf Generate Problem Definition file (.appdf) from Archive file
<Options>
-replace Do ask when replacing existing files
-nologo Do not display splash screen at startup
-fileinit Replace registry settings from mmg .ini file
-nocompat Do not display the upward compatibility dialog
-nobusy Do not display automation busy dialog
<Development Options>
-noF5 Disable F5 key from running simulation
-Automation Run as automation server
-fpmask off Reset floating point control word
-fpmask 0xh Set floating point control word
-varsum Import summary file into recdef file
-suppress Force dialog suppression (use with caution)
Example:
To convert *.bkp to *.inp :
apwn.exe -a -input filename.bkp
Note that the order of the switches is important.
Keywords: Aspen Plus Graphical User Interface
GUI
command line
Command line options
apwn
References: None |
Problem Statement: When running Aspen Plus in Equation-Oriented (EO) mode how do you enable/expose EO variables that are active in the simulation but not necessarily active in the EO variables sheet? | Solution: While a considerable number of variables are available to be adjusted in EO mode, there are a number of variables that are used in the simulation while in EO mode that are sometimes hidden or not visible. Most of the time when variables are not visible in EO it means they were probably not present or used while in Sequential Modular (SM) mode. To enable EO variables be sure to to enable variables or forms in SM first to ensure that those in EO will be exposed. Variables will appear in the EO variables form of the block once the SM models have been synchronized to the EO models. Below is an example of how to enable/expose performance curve variables for a compressor block.
EXAMPLE: How to enable/expose EO variables for a Compressor Performance Curve:
Enable the Operating specs tab by first entering Compressor block/Performance curve/number of curves/single curve at reference speed along with appropriate curve values.
The operating specs tab should now require information.
Input at a minimum a 'shaft speed' until the form is satisfied and ensure that the model runs even if the model has an error associated with it or is overspecified. This overspecification can be fixed later by changing the variable fixed/free specification and then re-enabled/disabled to have the correct degrees of freedom to solve the the equations.
At this point the EO shaft speed variable will be enabled in the block's EO variables form.
Go back to the performance curve setup menu/curve setup and select multiple curves if needed and the EO variable speed will still remain in the EO variable list.
Keywords: EO, COMPR, SHAFT SPEED, VARIABLE, hidden, exposed
References: None |
Problem Statement: Many times companies have proprietary component physical property databanks for their processes that need to be accessed by the end user. There are several steps involve to insure that the databanks are installed properly before they can be used. For version 2006, the Aspen Properties Enterprise Database was introduced as the new format going forward for storing property data for Aspen Tech software products. During a custom install of the software products like Aspen Plus, installation of custom property databanks to the end user's can also be included. This will minimize setup problems and insure uniformity of property databanks across the company. | Solution: There are several options for accessing component physical property databanks under the new Aspen Properties Enterprise Database system. The attached document covers the necessary steps for installation of property databases on individual local PC's running Aspen Plus and Aspen Properties during a silent install of the software. For other options such as accessing databases from central file servers please see the documentation for Aspen Properties Enterprise Database Manager.
Keywords: Aspen Properties Enterprise Database
APED
User databanks
User databases
Custom install
Silent install
References: None |
Problem Statement: How do you add liquid composition to a Heat Curve? | Solution: To add any additional properties to a Heat Curve (HCURVE):
1. Create a property set or sets for the properties desired on the Properties | Prop-Sets forms. If you started with one of the templates, HXDESIGN, a prop-set with all of the properties needed for the heat exchanger interface program will already be available.
2. Go to the Hcurve | Additional properties sheet and move the property sets from the Available list to the Selected list. You can have any number of property sets in the list.
Keywords: heatx
heat curve
References: None |
Problem Statement: What is the meaning of the parameter DLWC in the Wilke-Chang equation | Solution: DLWC indicates if the component is diffusing (value=1) or not diffusing (value=0). You can set the value in Properties=>Parameters=>Pure Component and choose scalar as parameter type. The default value is 1 which means that the component will be considered in the liquid diffusivity calculation.
Keywords: DLWC
Wilke-Chang
Diffusivity
References: None |
Problem Statement: How can I run a two-dimensional (2D) sensitivity analysis to generate a response surface? | Solution: It is possible to do 2D sensitivity analysis by varying multiple independent variables. The analysis will be carried out by repeatedly executing the simulation at all possible combinations of different values of all varied variables. The results are tabulated for variables specified by the user.
In the attached file, the impacts of feed temperature and the reflux ratio of a RadFrac column on the distillate flowrate and the mole fraction of methanol in the distillate are studied by sensitivity analysis block S-1. The results of the 2D sensitivity analysis can be plotted by Aspen Plus or the data can be copied plotted using a third party software.
A plot generated by Aspen Plus through the following procedure is shown below:
1. In the Results sheet of the sensitivity block, highlight the column for vary1 (feed temperature), then click on the X-Axis Variable under Plot menu at the top of the window.
2. Similarly, highlight the column for methane mole fraction, then click on the Y-Axis Variable under Plot menu.
3. Highlight the column for vary2 (reflux ratio), then click on the Parametric Variable under Plot menu.
4. Click on Plot|Display Plot to generate the graph.
Keywords: Sensitivity analysis
References: None |
Problem Statement: Liquid density values for water using NRTL or any other activity coefficient do not match those using the steam tables. | Solution: There are some limitations for the liquid density models. The problems seem to be especially large for water density. The specific heat and enthalpy of water also do not match the steam tables. For pure water streams simply use one of the steam table property methods (STEAM-TA, STEAMNBS, or STMNBS2). However, for mixtures that are primarily water, there are a few possibleSolutions to make the liquid density match, but users will need to verify how the changes affect their individual mixtures.
The basicSolution is to use a different method to calculate the mixture liquid volume. Go to the Properties | Property Methods | NRTL | Routes sheet and change the method for VLMX from VL2RKT to something else. You may also need to change the route
1. You can use COSTALD (VLMX22)
COSTALD is an empirical correlation that computes mole-volume from Tb, MW and SG. For very heavy components, the calculated liquid density may be abnormally high. For consistency with pure component results, replace the VL calculation with VL06.
2. You can use a mole fraction average mixing rule (VLMX26) or a quadratic mixing rule (VLMXQUAD).
These will use the pure component density which is from DIPPR which is generally accurate, but you will not have any mixing effect.
The quadratic mixing rule has an option to change option code 1 to a value of 1 to use the steam tables for water. This is done on the Properties | Property Methods | NRTL | Methods sheet for VLMX. This will give you the same results as the steam table.
The quadratic mixing rule was added in 2006.5 as an option to compute molar volume of solvents in an electrolyte mixture.
With i and j being components, the liquid volume quadratic mixing rule is:
Option Codes
Option Code
Value
Descriptions
1
0
Use normal pure component liquid volume model for all components (default)
1
Use steam tables for water
2
0
Use mole basis composition (default)
1
Use mass basis composition
Parameter
Parameter Name/Element
Symbol
Default
MDS
Lower Limit
Upper Limit
Units
VLQKIJ
Kij
-
x
-
-
-
Comparison of Calculated Water Densities with Different PropertyMethods
Temperature
Liquid Density
ASME Steam Tables
Calculated using Aspen Plus Properties
Saturated Liquid
STEAM-TA
RACKETT
COSTALD
QUADRATIC or IDEAL mixing
QUADRATIC mixing using Steam Tables for Water
F
LB/CUFT
LB/CUFT
LB/CUFT
LB/CUFT
LB/CUFT
LB/CUFT
32
62.414
62.418
63.537
62.529
62.597
62.418
200
60.107
60.108
57.766
60.306
59.991
60.108
See attached example file for the results in the table above.
Block S-B1 uses the Steam Tables
(Property Method STEAM-TA)
Block R-B1 uses the RACKETT model
(Property Method NRTL)
Block C-B1 uses the COSTALD model
(Property Method COSTALD was created by modifying NRTL to use VLMX22 and VL06)
Block Q-B1 uses the QUADRATIC mixing model
(Property Method QUAD was created by modifying NRTL to use VLMXQUAD)
Block Q1B1 uses the QUADRATIC mixing model with Steam Tables for Water
(Property Method QUAD1 was created by modifying NRTL to use VLMXQUAD and changing Option Code 1 to 1)
Keywords: None
References: None |
Problem Statement: When defining a variable for a stream, the Design-Spec, Sensitivity Analysis and Calculator blocks give the user a choice of STREAM-VAR and xxxx-FLOW or xxxx-FRAC variable types on the DEFINE and VARY sheets. Which is appropriate to use? | Solution: The xxxx-FLOW and xxx-FRAC variable types are applied to just one component in a stream, whereas the STREAM-VAR variable type has qualifiers that allows it to sample the flow rate of the entire stream (all components).
For example, MOLE-FLOW and MOLE-FRAC variable types apply to just one component in a stream, whereas the STREAM-VAR variable type with a MOLE-FLOW qualifier samples the mole flow rate of the entire stream.
The MOLE-FRAC variable applies to the mole fraction of one component in a stream. The MASS-FLOW/MASSFRAC and STDVOL-FLOW / STDVOL-FRAC variables work similarly.
For example, if you had a stream called AIRSTRM with 79 moles of Nitrogen, 20.9 moles of Oxygen, and 0.1 moles of Carbon Dioxide components, here are the values that each variable type would retrieve:
Keywords: DEFINE, VARY, DESIGN-SPEC, SENSITIVITY ANALYSIS, CALCULATOR BLOCK, MOLE-FLOW, MOLE-FRAC, MASS-FLOW, MASS-FRAC, STDVOL-FLOW, STDVOL-FRAC
References: TYPE STREAM Component VARIABLE Value
STREAM-VAR AIRSTRM not needed MOLE-FLOW 100 moles/hr
STREAM-VAR AIRSTRM not needed MASS-FLOW 2886 lbs/hr
STREAM-VAR AIRSTRM not needed STDVOL-FLOW 85.79 ft3/hr
MOLE-FLOW AIRSTRM Nitrogen not applicable 79 moles/hr
MOLE-FLOW AIRSTRM Oxygen not applicable 20.9 moles / hr
MOLE-FLOW AIRSTRM CO2 not applicable 0.1 moles/hr
MOLE-FRAC AIRSTRM Nitrogen not applicable 0.79
MOLE-FRAC AIRSTRM Oxygen not applicable 0.209
MOLE-FRAC AIRSTRM CO2 not applicable 0.001
MASS-FLOW AIRSTRM Nitrogen not applicable 2213 lbs/hr
MASS-FLOW AIRSTRM Oxygen not applicable 669 lbs/hr
MASS-FLOW AIRSTRM CO2 not applicable 4 lbs/hr
MASS-FRAC AIRSTRM Nitrogen not applicable 0.767
MASS-FRAC AIRSTRM Oxygen not applicable 0.232
MASS-FRAC AIRSTRM CO2 not applicable 0.002
STDVOL-FLOW* AIRSTREAM Nitrogen not applicable 67.78 ft3/hr
STDVOL-FLOW* AIRSTREAM Oxygen not applicable 17.93 ft3/hr
STDVOL-FLOW* AIRSTREAM CO2 not applicable 0.08 ft3/hr
STDVOL-FRAC* AIRSTREAM Nitrogen not applicable 0.790
STDVOL-FRAC* AIRSTREAM Oxygen not applicable 0.209
STDVOL-FRAC* AIRSTREAM CO2 not applicable 0.001
* The standard volumes are reported as standard liquid volumes at 60 degrees F. For further information on obtaining standard vapor volume flows, please see |
Problem Statement: How to create a sequence? | Solution: Aspen Plus has two calculation modes: sequential modular and equation oriented. When using the sequential modular run mode, the blocks are executed in a sequence. Each block is responsible for the calculation of its output streams, and this calculation can only be done once all its input streams are known. In the case of recycle, the user has also to select tear streams to allow some convergence algorithm (Weigstein, Broyden) to converge the flowsheet. In case of design specs, a convergence block also need to be created to repeat the calculation of the blocks involved in the control loop. A similar consideration exists for calculator blocks. In the case of equation oriented mode, there is no concept of calculation sequence as all equations are solved simultaneously.
In general, it is best to leave Aspen Plus make up the calculation sequence. This is because specifying a sequence for a complex flowsheet can be time consuming, error prone, and eventually wrong when done by a user, while Aspen Plus features various algorithm to work out very good calculation sequences. So we strongly advise the user to no specify a complete calculation sequence.
The attached word document gives some instructions on how to create a sequence with a simple example.
Keywords: sequence, convergence
References: None |
Problem Statement: In a previous release of Aspen Plus or Aspen Properties, there was an option to add a button on the Toolbar that would allow access to a local version of the Detherm databank using the Detherm Server Setup Utility available from the Start menu. How do I enable this option? | Solution: Access to a local version of the Detherm databank from Aspen Plus or Aspen Properties is not supported anymore. The recommended workflow is to work within your local Detherm installation and then export the desired data into an Aspen Plus or Aspen Properties Data Regession System (DRS) input file. The INP file can then be imported into Aspen Plus or Aspen Properties.
Keywords: Detherm
References: None |
Problem Statement: How do you use NRTL-SAC parameters for a component in a simulation using another property method such as NRTL? | Solution: This document explains how you can estimate NRTL binary interaction parameters for a new component based on NRTL-SAC-derived parameters (such as NRTL-SAC parameters derived through solubility regressions). A license for Polymers Plus in addition to Aspen Plus is required to use this methodology. ThisSolution will be updated for V7.1 since the NRTL-SAC data forms have changed for that release.
NRTLSAC is the current thermo model within Aspen Properties. In V7.1, the NRTL-SAC model will be added which will have the new data forms. Both of these models are based on the underlying research done on NRTL-SAC.
Once the NRTL binary parameters are defined, the new component can be used in NRTL calculations with other components whose binary parameters are already specified. This allows you to perform activity calculations, VLE calculations, etc. using NRTL incorporating the new component.
The ability to estimate parameters for NRTL based on NRTL-SAC parameters is actually one of the capabilities within the Aspen Physical Property System. For instance, you could alternatively generate VLE data using the predictive UNIFAC property method and use the generated data to determine the binary parameters for the Wilson property method.
In the following example, however, we will focus purely on using NRTL-SAC parameters to determine NRTL binary parameters.
(Note - the following example is based on Aspen Properties 2006.)
In this example, we have started from an Aspen Properties aprbkp file which contains various solvents, as well as the NRTL-SAC regressed parameters (X, Y+, Y-, Z) for a component named DRUG. (See figure below.) The aprbkp file that we started with is called 130_Solvents_NRTLSAC.aprbkp, and it is included for your reference.
Now open the Properties folder in the tree on the left, and choose Specifications. NRTL has been chosen as the property method for this file:
Next we need to specify what type of data to regress. In the left pane of the Browser, click the Data folder. The Data object manager appears. Click the New button. In the Create New ID dialog box, enter an ID or accept the default. (We have named the new ID NRTLPRM in this example.) Then choose MIXTURE in the Select Type list box, and click OK:
On the Setup sheet, choose the type of property data in the Data Type list box. In this case, choose GEN-TPXY (near the bottom of the drop-down list). Next, choose which components you would like to regress NRTL binary parameters for. In this case, we will regress binaries for a Drug-Acetone system at 25 deg C:
Now select the Data tab. This tab will be used to specify the liquid phase compositions which will be used during the regression. On this tab, click the Generate Data button. In the Generate Binary VLE or LLE Data dialog box, select the NRTLSAC property method (at the bottom of the list of methods):
Now click the Generate button to fill in the compositions that will be used for the calculations:
Next, go to the Regression subfolder within the Properties folder in the tree on the left. Select the Binary subfolder. Within the Setup tab, choose NRTL as the property method (you may have to change it from NRTLSAC) and choose NRTLPRM (or whatever you used as the Data Object ID) as the Data set. (Delete any other Data sets that are already in this file. To do this, select the rows containing the additional data sets, then right-click and select Delete Row.) When you are done, the Setup tab should look like this:
Now select the Parameters tab. Choose Binary parameter in the Type field. For the Name/Element field, choose NRTL. Then click on the space next to the Name/Element drop-down menu (circled in red on the figure below) and enter a 1.
Continue filling out this dialogue box with the appropriate information. In this case, we have chosen Acetone and Drug. Note that we have also entered a binary parameter regression for Drug and Acetone (so that we get both parameters).
Finally, click the Start button (the triangular blue play button near the top) to run the regression. Choose the run the Binary regression (not Pure).
Click OK in the dialogue box above. When the regression is complete, you can go to the Properties/Regression/Binary/Results folder to see the regressed parameters:
To see how good the fit is, you can also click on the Residual and Profiles tabs.
The final Aspen Properties file built from this example entitled 130_Solvents_Final.aprbkp is included for your reference.
Keywords: None
References: None |
Problem Statement: After retrieving the pure component parameters, the TREFHL parameter (reference temperature for the liquid enthalpy reference state) doesn't display on the Pure Component Parameter scalar input form nor does it appear on the REVIEW-1 input form. | Solution: In general, only parameters that are used in the selected Property Methods are retrieved or are available for input.
The TREFHL parameter will not appear in any list unless the DHL09 route ID has been selected for the DHL Property, use liquid reference state is checked at the bottom right of the Properties Specification form, or the WILS-LR or WILS-GLR property method is used. For more information on changing the route ID for property methods that use a vapor enthalpy reference state (the default for most property methods), please seeSolution 3100 (in the cross-references in thisSolutions).
Keywords: property parameters
References: None |
Problem Statement: Is it possible to specify the number of exchangers in series and parellel in a HEATX block? | Solution: In 11.1, it is possible to specify the number of exchangers in series using the Shortcut method only. To model exchangers in parallel, a MULT block should be put before and after the HEATX block.
In 12.1, it is possible to specify heat exchangers in series and parallel also for the rigorous method.
The HEATX model in 12.1 will also
allow rating for shortcut method
add constant UA as additional u-option method. Area will be is optional if UA is specified.
display UA, number of shells in series and in parallel on the output forms.
In addition, there are some minor fixes:
corrected NTU calculation method in hxre.f. Previous version was using calculated area instead of actual area to determine NTU which can be incorrect for over or under surfaced exchangers. the corrected method is to use terminal temperature to determine P_ref and ntu is the ration of p_ref/thetaref which neither p_ref or thetaref is estimated.
use a more robust bisection method to find NTU. for the unconverged NTU, the estimated fmtd may be more close to the actual fmtd.
corrected xi calculation for multiple shells in series. fmtd seems to match B-JAC Hetran fmtd now after this correction.
corrected input value NTU which is used to calculate xi for single E shells in series. The correct NTU should be the fraction of NTU if multiple shells in series is involved.
Keywords:
References: None |
Problem Statement: Is it possible to have a reactive distillation and have the product show up in a solid stream? The React-dist does not allow a reaction product in a solid substream. Is there any other way? | Solution: CISOLIDS and NCSOLIDS do not participate in reactions in RadFrac. The reaction needs to be completed using a reactor before or after the RadFrac column.
Keywords: cisolid
ncsolid
References: None |
Problem Statement: Analyzer EO Variables | Solution: Analyzer EO Variables
A change introduced in V7.0 had compatibility effects not reported until now. Adding support for solids to the EO formulation of Analyzer required reformulating the model slightly to make it more like other models. Specifically, the DELTA_ENTH variable was removed, and a new DUTY variable was added. This is not exactly the same, since the DELTA_ENTH was on a molar basis (J/kmol) while DUTY is on a time basis (J/s).
This has consequences for users who have saved X or VAR files from version 2006.5 or earlier which they intend to load into newer versions, and for anybody who directly manipulated or accessed this EO variable from scripts, etc. In most cases, the variable can be converted by multiplying its value by the molar flow rate in kmol/s and assigning the result to the DUTY variable. Another way of handling it is to swap specs after loading a VAR file so that DUTY is calculated, and once the new DUTY value is calculated, swap back.
Keywords: DELTA_ENTH, DUTY. Analyzer
References: None |
Problem Statement: How does the RStoic conversion specification treat electrolytes? | Solution: When using the True species approach, the conversion will only apply to the true species concentration. For example if you have HCL and H2O completely dissociating into H3O+ and CL-, then a reaction in RStoic using key component HCL will not occur.
When using the Apparent composition approach, the conversion will apply to the apparent species concentration. In the above example, if HCL is the key component, then the reaction will occur, as long as there is HCL as an apparent component.
Keywords: RStoic, electrolytes, reaction
References: None |
Problem Statement: After entering Txy data and regressing the NRTL 2 (Bij and Bji) parameters, the sum of square error is very high (over 1 million), and when reviewing the Regression profile results, the estimated temperature in the first row is much higher than the experimental temperature. | Solution: Normally, the temperature data should have good agreement between the experimental and estimated columnar data. However, a common user error, reversing the composition data (entering component A's composition in the component B column) will cause a temperature error, especially if there is a large difference in boiling point between the 2 components you are regressing.
When you see a large difference in estimated versus experimental temperature, focus on data entry errors for the TPXY, TXY or TXXY data.
Keywords: Regression, DRS, TPXY, TXY, profile, residual, sum of squares error, EST, estimated, EXP, experimental
References: None |
Problem Statement: Why do my design-specs, and sensitivity analyses require a Fortran compiler when they do not have any Fortran or arithmetic expressions? Also, I have reviewed | Solution: document 104149, and my Calculator block does not contain any arithmetic expressions that require a compiler, yet Aspen Plus produces errors about the missing Fortran compiler?
Solution
When Aspen Plus keeps searching for a Fortran compiler, even though one is not needed, it is because there is a setting that has been accidentally set to force the use of a compiler with Design-Specs, Calculator Blocks, Sensitivity Analysis, and Optimization.
Navigate to the Setup | Simulation Option | System sheet, and be sure the Interpret all inline Fortran statements at execution time option for the Fortran compilation is selected. The Write inline Fortran to a subroutine to be compiled and dynamically linked should NOT be selected. To compile Fortran requires you have a supported compiler installed and Aspen Plus configured to use it. Please see below:
Keywords: Design-Spec, Design-Specification, Sensitivity Analysis, Calculator, FORTRAN, Interpret, compile
References: None |
Problem Statement: The unit of measure for HENRY's component data input into Aspen Plus is pressure. However, typically HENRY's component data found in literature are expressed in pressure/concentration such as Atm/(mol/liter). How do you get HENRY's component data calculated in Aspen Plus in the pressure/concentration units found in literature? | Solution: Ideally, HENRY constants could be calculated with a PROP-SET.
In 2006.5, two new Property Sets were added:
1. GAMUSAQ: Unsymmetic activity coefficient based on the aqueous reference state
This property is calculated from gamma(i in the mixture)/gamma infinity of i in water. GAMUSAQ is different from GAMUS in that GAMUS is calculated from gamma(i in the mixture)/gamma infinity of i in the mixed solvent. Here i refers to Henry's components.
2. HNRYMX: Henry's constant of component i in the mixture, where i is the Henry's component
In the interim, Aspen Plus will calculate the HENRY constant using a FLASH2 and SENSITIVITY block. The attached example BKP file reproduces the Acetylene (C2H2)/WATER HENRY's data from Perry's Handbook (6th edition, p.3-101) that used in the regression inSolution ID106047.
The example file contains a single FLASH2 block with a single feed containing the solute and solvent components at an arbitrary flowrate. A PROP-SET is created to retrieve the partial pressure of the solute in the FLASH2 block vapor outlet. The FLASH2 block specification is Temperature and Pressure, again arbitrary. In the SENSITIVITY block, the partial pressure of the solute in the vapor and the mole fraction of the solute in the liquid from the FLASH2 block is accessed through DEFINE variables. Then, the SENSITIVITY varies the FLASH2 block Temperature and calculates the HENRY's constant at the various temperatures by dividing the partial pressure by the mole fraction.
Row/Case
VARY 1
FLASH
PARAM
TEMP
C
C2H2
PARTIAL
PRESSURE
ATM
C2H2
LIQUID
MOLE
FRACTION
HENRY
ATM/MOLF
HENRY
X 10-3
ATM/MOLF
HENRY
ATM/CONC
HENRY
X 10-3
(Perry's)
ATM/MOLF
1
0
4.99402027
0.00692004
721.674291
0.72167429
12.8907763
0.72
2
5
4.99144944
0.00596095
837.357925
0.83735792
15.0095681
0.84
3
10
4.98794942
0.00520475
958.344015
0.95834401
17.2433478
0.96
4
15
4.98324714
0.0046022
1082.79495
1.08279495
19.5609012
1.08
5
20
4.97700813
0.00411752
1208.73718
1.20873718
21.9279834
1.21
6
25
4.96882726
0.00372438
1334.1342
1.3341342
24.3085629
1.33
7
30
4.95821904
0.00340313
1456.95844
1.45695844
26.6660771
1.46
Keywords: HENRY
HENRY's data
HENRY's constant
References: None |
Problem Statement: Can components in a CISOLID or NC substream participate in electrolyte Chemistry? | Solution: Only components in the MIXED substream can participate in Chemistry. The CISOLID substream and the NC substream are inert with respect to phase equilibrium. Salt reactions need to involve a solid specied in the MIXED substream.
CISOLID or NC components can be moved to the MIXED substream (so they can participate in Chemistry) with an RStoic block.
Keywords: electrolytes
salt salts
References: None |
Problem Statement: When trying to populate an Aspen CIM-IO transfer record via Aspen Sqlplus, the following error appears:
Error reading memory in the repeat area. Cannot follow chain to field.
If you go to the InfoPlus.21 Administrator, enter some number in the repeat area (IO_#TAGS) and double click, there are no occurrences available. | Solution: The problem actually is no an Aspen SQLplus problem. Rather, it is an Aspen Infoplus.21 configuration issue. What is happening is that the user is Selecting a ghost field from a record in which the ghost selector field is not pointing at a correct selection from the ghost selector record.
For the specific IOGetDef record the repeat area of the transfer record has indeed links to 2 ghost selector records, io-deadbands and io-eu-conv. (The fixed area also has a link to the io-groups ghost selector). You need to check 1st_selection_value of the ghost selector, for example io-deadbands and make sure it is configured correctly (by default it has No deadband). It might be that it has a number instead.
Keywords: Repeat area
Can not follow chain
References: None |
Problem Statement: Is is possible to have an adiabatic SEP or SEP2 block? | Solution: There is no way of specifying an adiabatic SEP or SEP2 block. You need to use a design specification and vary the temperature. You also need a Calculator to equate all of the temperatures in all of the outlet streams. The Calculator block should be sequenced to execute BEFORE the SEP or SEP2 block.
An Aspen Plus example file. This file can be opened in 2004.1 and higher.
Keywords: None
References: None |
Problem Statement: Printing the flowsheet in Aspen Plus causes the layout to change and reduces the readability of the flowsheet. | Solution: Changing the Margin size can resolve some formatting problems.
Go to File / Page Setup and try setting all the margin values to 0.5 rather than 12.7 which is the default.
Keywords: Print, printer
References: None |
Problem Statement: I have several versions of Aspen Plus installed on my computer. How can I force a specific version to be used when I call the GetObject function from my Excel macro? | Solution: You need to use this:
set ap = GetObject(path, class)
where:
path is the string to the aspen plus bkp file (e.g. d:\test.bkp)
class is a string which specifies which version you want to start
for example:
To start 12.1:
set ap = GetObject(d:\test.bkp, Apwn.Document.12.1)
To start 2004.0:
set ap = GetObject(d:\test.bkp, Apwn.Document.13.1)
To start 2004.1:
set ap = GetObject(d:\test.bkp, Apwn.Document.13.2)
To start 2006:
set ap = GetObject(d:\test.bkp, Apwn.Document.20.0)
Keywords:
References: None |
Problem Statement: Linking Aspen Plus with Excel 2007 from Excel 2003 files | Solution: Microsoft has different means of referring cells in Excel 2003 and Excel 2007. There seems to be some compatibility issues with the reference names given by default in Excel 2003 and Excel 2007. This has nothing to do with Aspen Plus and the sheet works fine after opening the same sheet in Excel 2003 and deleting the conflicting names.
Keywords: Excel 2007, Excel 2003, Aspen Plus Linking, Excel Calculator
References: None |
Problem Statement: What is the difference between OLI and ElecNRTL? | Solution: OLI's Electrolyte Model is a product of OLI Systems. It is purchased directly from them.
OLI's Electrolyte Model is a Predictive Equation of State and Activity Coefficient Model based upon the Helgeson equation of state and parameter regression and proprietary estimation techniques published experimental data. Activity coefficients based on the combined work of Bromley, Zemaitis, Meissner, Pitzer, and OLI technologists are used for complex, high ionic strength systems. This model provides general simulation capability giving accurate prediction for almost any aqueous chemical mixture over the range:
Temperature: -50 to 300 C
Pressure: 0 to 1500 bar
Ionic strength: 0 to 30 molal
OLI/Aspen alliance allows Aspen users to license OLI databanks for use with a variety of Aspen Products.
Like electrolytes wizard in Aspen Plus, OLI generates species and reactions and retrieves equilibrium constants. These can be used in Aspen simulations similar to using a Property Method.
See http://www.olisystems.com for more information.
The ElecNRTL model built into Aspen Plus/Properties provides another thermodynamically consistent model for aqueous electrolyte systems. This equation was developed with the local composition concept. This concept is similar to the NRTL (Non-Random Two Liquid) model for nonelectrolyte systems (Renon and Prausnitz, 1968). With only binary parameters, the equation satisfactorily represents physical interactions of true species in aqueous single electrolyte systems and multicomponent electrolyte systems over wide ranges of concentrations and temperatures. This model can represent infinitely dilute electrolyte systems (where it reduces to the Debye-Huckel model), nonelectrolyte systems (where it reduces to the NRTL model), and pure fused salts. It connects these limiting systems. The equation has been extended to model mixed solvent electrolyte-systems (Mock et al., 1984).
To compare OLI with ElecNRTL
? Both thermodynamic models are of comparable quality
Electrolyte Wizard is initially easier to use
OLI databank has more species, more reactions (e.g., Rare Earth ions; Redox reactions)
OLI requires less user intervention
ElecNRTL is better for adding new species, estimating and regressing parameters, changing components
ElecNRTL applies up to the highest concentrations
ElecNRTL is included in Aspen Plus (Aspen Properties?)
Keywords: None
References: None |
Problem Statement: How does RGibbs handle multiple CISOLID substreams? | Solution: RGibbs, in past versions, did not support multiple CISOLID substreams, but in version 2006 there was a change to its behavior when it nevertheless encountered multiple CISOLID substreams. Since version 2006, RGibbs would merge all the CISOLID substreams into the first CISOLID substream and react that substream if the option to react solids was selected. In earlier versions, RGibbs would only react the first CISOLID substream and ignore the others, treating them as inert. Now there is a new option on the Setup | Specifications sheet to Merge all CISOLID substreams into the first CISOLID substream. The default is not to merge, consistent with results from before version 2006 but a change from results in versions 2006 through V7.1. If you select this option, you will reproduce the results from these recent versions. RGibbs still does not support reacting multiple CISOLID substreams while leaving them as separate substreams.
RGibbs places all pure solids in the last outlet stream unless you specify otherwise on the Setup | Assign Streams sheet. RGibbs can only react a single CISOLID substream (the first one, if there is more than one), but if you select Merge all CISOLID species into the first CISOLID substream on the Setup | Specifications sheet, then it will merge the CISOLID substreams and react the result. In any case, the first CISOLID substream contains all conventional solids reaction products defined as pure solid phases. RGibbs places the solidSolution phases in the MIXED substream of the outlet stream(s).
If you have multiple CISOLID substreams, RGibbs can only react the first one. If you select Merge all CISOLID species into the first CISOLID substream then it will merge all the CISOLID substreams into the first one and then react it per the Solids Phases setting. Otherwise it will only react the first CISOLID substream and treat the others as inert.
Keywords: MERGE-SOLIDS
References: : CQ00211918 |
Problem Statement: What is the easiest way to verify which security method is being used by InfoPlus.21? | Solution: There are two ways to tell which security method is being used:
1) Open the Data Source Configuration Tool (Start -> Programs -> AspenTech). If MS Access is checked, then it's Local Security, otherwise it's Aspen Framework Security.
2) Go to the computer's Control Panel and double click the Add or Remove Programs icon. Check the list of Currently installed programs and look for either Aspen Local Security or Aspen Framework Security.
Keywords: AFW
References: None |
Problem Statement: The h21archive process will only attempt to open the arc.key file one time. If another program is accessing that file, such as a system backup or a virus scan program, the file cannot be opened and the history subsystem (h21archive.exe) will crash. You may see this error in the error.log file located in the directory where the repository resides on the NT file system:
comp_rate() cannot open key file | Solution: Stop and restart InfoPlus.21.
Keywords: comp_rate
error.log
key
References: None |
Problem Statement: Error 53 returned by task service:
ERROR: Error 53 returned by task service. Network path not found, received when trying to start Infoplus.21. This message is most commonly seen on laptop computers as they are not connected to the network. | Solution: is applicable to the Windows 2000 operating system only. To configure the MS Loopback adapter on the Windows XP operating system, please refer to Microsoft's KB article 839013
http://support.microsoft.com/default.aspx?scid=kb;en-us;839013&Product=winxp
Keywords: Error 53
MS Loopback
Laptop
network
remote
References: None |
Problem Statement: How do I resolve the Aspen Calc message:
Error executing calculation: Error Executing Method FormulaName: Component [name] not found in the Aspen Properties property package, in formula FormulaName at line #, in formula FormulaName at line # | Solution: What Aspen Calc requires is:
1. Each Component ID has exactly 8 characters
2. Component IDs used in Aspen Calc scripts must be exactly the same as Component IDs defined in Aspen Properties
As a result, when the user creates Aspen Properties models (i.e. aprbkp or aprinp files) to generate aprpdf files, the user must use exactly 8 characters for each Component ID.
For example
Component ID
Type
Component Name
Alias
WATER
Conventional
WATER
H20
Modify to Component ID with 8-char
HYDROGEN
Conventional
HYDROGEN
H2
OK (8-char)
NOTE: The name used in Aspen Calc’s Component List is case sensitive; it has to match exactly the one used (Component ID) in the aprpdf file.
Keywords: Aspen Calc, Aspen Properties, Formulas, Aspen Properties Flash, Aspen Properties General, Aspen Properties Toolkit, CALPRP, PPMON_CALPRP
References: None |
Problem Statement: What can cause an Aspen Calc calculation to give the message:
Error writing local InfoPlus.21 field : No such record | Solution: This means an Aspen Calc calculation is bound to an Aspen InfoPlus.21 tag that may have been deleted.
Keywords: missing tag
deleted tag
error message
no such record
Aspen Calc
Aspen InfoPlus.12
missing binding
no binding
References: None |
Problem Statement: How do I avoid the error The client invoked has disconnected from its clients when trying to import an XML into Aspen Calc? | Solution: This is similar to the error message found in Knowledge Base articles 116951 and 121866 that address other Aspen products. Do not try the fixes recommended in thoseSolutions as they do not address Aspen Calc.
To fix the issue with Aspen Calc, you only need to restart the AspenTech Calculator Engine service.
To do this:
-Click start and search for a windows application called services. It should have two interlocked gears as the icon. Open this application (You may need to be running it as an administrator).
-Navigate to the AspenTech Calculator Engine and right-click on it. Press Restart.
-Once the service stops and restarts correctly, close all open Aspen Calc windows.
-Once you re-open them, you should be able to import the XML as intended.
Keywords: Aspen Calc
Importing XML
References: None |
Problem Statement: This knowldege base article explains under which circumstances the following message:
WARNING: Data in 'D-IP_Analog ' will not be copied to target
will appear in the upgrade.out file after an InfoPlus.21 snapshot has been upgraded. | Solution: The message
WARNING: Data in 'XXXX ' will not be copied to target
indicates the following:
The record (XXXX) appears in both the source and target database snapshots.
The contents of the record in the source snapshot is different to the contents of the record in the target snapshot.
The record is not listed in the OKTOMODIFY.inp file.
When this situation occurs the record definition in the target snapshot will remain as-is. It will not be overwritten by the record definition in the source snapshot.
Note: All records not listed in OKTOMODIFY.inp that have not changed between versions will not be listed, such as FieldName records, other selector records etc.
Keywords:
References: None |
Problem Statement: Can the Aspen InfoPlus.21 Task Service be stopped and restarted while Aspen InfoPlus.21 is running? | Solution: The Aspen InfoPlus.21 Task Service can be restarted while Aspen InfoPlus.21 is running with no ill-effects to Aspen InfoPlus.21; however, Aspen InfoPlus.21 processes do not inherit environment changes from the Aspen InfoPlus Task Service until InfoPlus.21 is restarted.
You will not be able to start or stop InfoPlus.21 programs using the InfoPlus.21 task manager, stop Aspen InfoPlus.21, or explore the Aspen InfoPlus.database using the Aspen InfoPlus.21 Administrator while the Aspen InfoPlus.21 Task Service is stopped. Queries, applications, or batch procedures using the utility TSK_CLIENT will also fail while the service is not running.
Keywords: task service
TSK_CLIENT
References: None |
Problem Statement: One optional feature of Aspen InfoPlus.21's automated backup program (TSK_HBAK) is the ability to backup all shifted/changed file sets. However, if the user enables the automated backup of the shifted/changed file sets after many file sets flagged as shifted, changed or shifted/changed have been saved to disk, the initial backup of all such file sets may take a long time. This knowledge base article provides a method to estimate the time required to backup a large number of file sets with TSK_HBAK. | Solution: The file set backup time is dependent upon various factors for each individual system such as the memory, drive fragmentation, available resources, etc. on each Aspen InfoPlus.21 server. Therefore, it is necessary to develop a methodology to estimate the time required for TSK_HBAK to backup a large number of file sets on individual servers.
In order to estimate the time required for TSK_HBAK to backup a large number of file sets, you need to determine the rate at which TSK_HBAK can backup data on your specific server. The necessary data to make this calculation is readily available in the h21arcbackup log file if your site currently uses TSK_HBAK to backup the active file sets. The h21arcbackup log file is located here:
Program Files\AspenTech\InfoPlus.21\c21\h21\etc
The H21arcbackup log file has entries such as shown below. Obtain from this file the completion time for the backup of one active file set.
05-SEP-06 10:29:00.0 - ARCBACKUP Info: Begin saving history system files.
05-SEP-06 10:29:00.0 - ARCBACKUP Info: Paused archiver TSK_DHIS
05-SEP-06 10:29:01.0 - ARCBACKUP Info: Begin saving active archive files for repository TSK_DHIS.
05-SEP-06 10:29:01.1 - ARCBACKUP Info: Resumed archiver TSK_DHIS
05-SEP-06 10:29:02.1 - ARCBACKUP Info: Finished scheduled processing. Completion time: 0.035000 minutes.
Next, measure how large the file set was that was just backed up. This can be done by measuring the size of the new folder that was created in
Program Files\AspenTech\InfoPlus.21\c21\h21\backups\active
when the active file set backup operation above was run. For the backup in this example, the newly created folder which held the backup of the active file set was 5.3 MB in size.
Since it took 0.035 minutes to backup 5.3 MB of data you can calculate the rate at which data was backed up.
Amount of data backed up / Time required to backup data = Data backup rate
5.3 MB / 0.035 minutes = 151.4 MB/minute
To estimate how long it will take to backup a large number of file sets, assume that a production Aspen InfoPlus.21 server has 100, 1 GB file sets that are flagged as shifted/changed and have never been backed up with TSK_HBAK. The time required to backup all of these file sets the first time TSK_HBAK executes the backup for shifted/changed file sets will be:
Amount of data to be backed up / Data backup rate = Required backup time
100,000 MB / 151.4 MB per minute = 660.5 minutes = 11 hours
Note: The system used to generate the backup time for this example had the following specifications:
1 GB RAM
1.6 Ghz processor (Pentium M)
Keywords: back up
recover
References: None |
Problem Statement: During installation of AMS products, user may receive the following error codes:
Error code: -6001
Error code: -6002
Error code: -7002
What do they mean? | Solution: This is likely due to an error in the InstallShield self-update. To resolve the issue, perform the following steps:
1. Delete all the files in the %Temp% directory.
2. Delete the folder named 0701 in C:\Program Files\Common Files\InstallShield\Professional\RunTime directory.
3. Load in the DVD media and re-install.
Keywords: 6001
6002
7002
References: None |
Problem Statement: Is there a way to get Visual Basic (VBA) to prepare a list of each unit operation that consumes 1 or more types of utilities? | Solution: Please see the attached spreadsheet and its cmd_Utilities subroutine on SHEET1. The code first counts the number number of utility types and reports their names, then it counts the number of consumers (blocks/unit ops) of each utility and reports their names, consumption rate and unit of measure.
Here is the final report in the spreadsheet
Util Type
Unit Name
Consumed
Dim Units
COOLWAT
COLUMN
13933.64
lb/hr
COOLER
846.5226
lb/hr
STEAM
HEATER
4491.389
lb/hr
COLUMN
1983.042
lb/hr
Here is the code:
Private Sub cmd_Utilities_Click()
Dim Ucount As Integer, Uname(20) As String, i As Integer, j As Integer, Uconsumers(20) As String
Dim RowCounter As Integer
'count number of utilities
Ucount = go_Simulation.Tree.FindNode(\Data\Utilities).Elements.Count
'capture the utility names
For i = 0 To Ucount - 1
Uname(i) = go_Simulation.Tree.FindNode(\Data\Utilities).Elements(i).Name
Uconsumers(i) = go_Simulation.Tree.Data.Utilities.Elements(Uname(i)). _
Output.UTL_USAGE.Elements.Count
Next i
' write the utility type and amount consumed by each consuming unit
RowCounter = 0
For i = 0 To Ucount - 1 'this is the outer loop for each utility type
Range(utilities).Offset(RowCounter, 0) = Uname(i)
For j = 0 To Uconsumers(i) - 1
'write the unit name
Range(utilities).Offset(RowCounter, 1) = _
go_Simulation.Tree.Data.Utilities.Elements(Uname(i)).Output.UTL_USAGE.Elements(j).Name
'write the unit's utility consumption
Range(utilities).Offset(RowCounter, 2) = _
go_Simulation.Tree.Data.Utilities.Elements(Uname(i)).Output.UTL_USAGE.Elements(j).Value
' write the dimensional unit for the utility consumption
Range(utilities).Offset(RowCounter, 3) = _
go_Simulation.Tree.Data.Utilities.Elements(Uname(i)).Output.UTL_USAGE.Elements(j).UnitString
RowCounter = RowCounter + 1
Next j
Next i
End Sub
Keywords: VBA, Excel, utilities, aspen plus, usage rates
References: None |
Problem Statement: You want to prevent an automatic service or application start up when logging on | Solution: Microsoft windows 2000/Xp/Vista/7 systems have an inbuilt tool called MSCONFIG,accessible via the windows' RUN key,under the STARTUP tab uncheck the unwanted service or application.This action prevents it from starting up automatically.
Keywords: Msconfig,automatic startup
References: None |
Problem Statement: What is the alpha_dash variable in the Equation-Oriented (EO) formulation of an RCSTR reactor? What's the difference between alpha_dash and vapor fraction? | Solution: For a RCSTR reactor, the EO variable RCSTR.ALPHA_DASH is the ratio of [the reactor volume occupied by vapor phase] to the [total reactor volume]. This is a block variable. In Graphical User Interface, the reactor volume occupied by vapor phase and the total reactor volume can be found in the Blocks | RCSTR | Results | Summary folder.
Vapor fraction is based on mole and is for streams. Alpha_dash is based on volume and is for the reactor. When the outlet stream vapor fraction is 1, alpha_dash will be 1 as well.
Keywords: RCSTR, ALPHA_DASH, vapor fraction
References: None |
Problem Statement: In a stream where I set the input of 91 kg/sec, but result and sequential base for the entire flowsheet is 361 tons/hr. That is simply wrong, what is up there? | Solution: A long ton used in the UK is 2240 lbs, a short ton used in the USA is 2000 lbs, and a metric ton or tonne is 2204.6 lbs.
In Aspen Plus a ton is a short ton and tonne is a metric ton.
Wikipedia has more information about the definitions of ton. The following is an excerpt.
http://en.wikipedia.org/wiki/Ton
There are three similar units of mass called the ton:
1. long ton (simply ton in countries such as the United Kingdom which formerly used the Imperial system of weights and measures) is a weight ton or gross ton, and is 2,240 lb (exactly 1,016.0469088 kg). In the UK and most of the areas which used the Imperial system, the metric tonne (1,000 kg), which it is conveniently very similar to?less than 2% difference?is the only form of ton legal for trade.
In the iron industry in the 17th century and 18th century, a ton shortweight was the standard 2,240 lb, whereas a ton longweight was 2,400 lb (the hundredweight being 120 lb).
The long ton is used for petroleum products such as aviation fuel.
Deadweight ton (abbreviation 'dwt') is a measure of a ship's carrying capacity, including bunker oil, fresh water, crew and provisions. It is expressed in metric tons (1,000 kg) or long tons (2,240 pounds, about 1,016 kg)[1]. This measurement is also used in the U.S. tonnage of naval ships.
Increasingly, metric tonnes are being used rather than long tons in measuring the displacement of ships. See tonnage.
2. short ton (usually called simply ton, in the USA or sometimes called a net ton) = 2,000 lb (about 907.18474 kg).
Harbour ton used in South Africa in the 20th century, equal to 2000 pounds or one short ton.
3. metric ton, usually referred to as a tonne, is 1,000 kg (or 1 Mg) or approximately 2,204.6 pounds.
Both the long ton and the short ton are composed of twenty hundredweights, each having different values for the hundredweight (112 and 100 pounds respectively). Prior to the 15th century in England, the ton was composed of 20 hundredweights, each of 108 lb, giving a ton of 2,160 pounds.
Assay ton (abbreviation 'AT') is not a unit of measurement (nobody ever has x assay tons of something), but rather a standard quantity used in assaying ores of precious metals; it is 29 1/6 grams (short assay ton) or 32 2/3 grams (long assay ton), the amount which bears the same ratio to a milligram as a short/long ton bears to a troy ounce. In other words, the number of milligrams of a particular metal found in a sample of this size gives the number of troy ounces contained in a short/long ton of ore.
In documents which predate 1960 the word ton may be spelt tonne, however in more recent documents the spelling tonne refers exclusively to the metric tonne.
In the context of nuclear power plants, tHM and MTHM mean (metric) tonnes of heavy metal, and MTU means metric tonnes of uranium. In the steel industry, the acronym THM has the meaning 'tons/tonnes hot metal', which refers to the amount of liquid iron or steel that is produced (particularly in the context of blast furnace production/specific consumption).
A dry ton or dry tonne has the same mass value, but the material (sludge, slurries, compost, and similar mixtures in which solid material is soaked with or suspended in water) has been dried to a relatively low, consistent moisture level (dry weight). If the material is in its natural, wet state, it is called a wet ton or wet tonne.
In the U.S. mining industry, ' T ' is used to distinguish the traditional ton from the metric ton, but ' T ' is also the SI symbol for the tesla. The symbol 't', traditionally used for the long or short ton, is now reserved for the metric tonne.
There are also the units of force based on each of these three mass units, but none are acceptable for use with SI. The tonne force, like the kilogram force, is no exception. Only the tonne as a unit of mass is acceptable for use with SI.
1 short ton force = 2000 pounds-force (lbf) = 8.896443230521 kilonewtons (kN)
1 long ton force = 2240 lbf = 9.96401641818352 kN
1 tonne force = 1000 kgf = 9.80665 kN
The freight ton or measurement ton is a unit of volume used for describing ship capacities (tonnage) or cargo. One measurement ton is equal to:
40 cubic feet
1.481(481) cubic yards (the 481 digit sequence repeats infinitely)
1,132.67386368 litres
1.13267386368 cubic metres
The measurement ton is abbreviated as M/T, MT, or MTON, which can cause it to be confused with the metric ton.
Keywords: None
References: None |
Problem Statement: How do I know whether valve is choked or not in Aspen Plus application? | Solution: In the Valve Unit Operation if you select a Calculation Type of either design (Calculate valve flow coefficient for specified outlet pressure) or rating (Calculate outlet pressure for specified valve), then one can see the choking status on the Value Results | Summary sheet.
With these Calculation Types, the Check for choked valve option will be activated on the Calculations Options sheet.
When checked, Valve calculates the choked flow pressure drop and compares it with the calculated/specified valve pressure drop, and reports the choking status as Valve is/is not Choked.
When checked and a liquid phase is present in the inlet stream, you must also specify the pressure recovery factor on the Valve Parameters sheet.
When unchecked, Valve reports the choking status of the valve as Choking is not Checked
Note:
When the Aspen Plus Valve model is in design mode, the choked pressure drop is calculated but not used. A warning is issued if the calculated pressure drop exceeds the choked pressure drop.
In rating mode, the minimum outlet pressure can use the lower limit for simulation, be set equal to the calculated choked outlet pressure, or set to a user-specified value. In the latter two cases, an error is issued if the calculated pressure drop exceeds the limit and the outlet stream pressure is set equal to the minimum outlet pressure.
Keywords: Valve, Choking etc;
References: None |
Problem Statement: It is sometimes necessary to identify each particular instance of a running task in the InfoPlus.21 Manager. For example, if 3 TSK_IQ# processes simultaneously run on the server, the Windows Task Manager will show 3 instances of iqtask.exe. Each instance of iqtask.exe can be identified by its Process ID (PID) number if the PID number is known.
This knowledge base article will describe how to retrieve the PID number of each running task in the InfoPlus.21 Manager so that this information can be used to identify the specific instance of the process. | Solution: PID information for all InfoPlus.21 running tasks (as seen in the running task list of the InfoPlus.21 Manager) can be found in two places.
1. The registry of the InfoPlus.21 server at the following location:
HKLM | Software | AspenTech | Infoplus.21 | 6.0 | Group200 | Running Tasks
Note: This example was written for v.6.0. Other versions will have a slightly different registry path as the version number in the path will differ.
Users who wish to write a program to retrieve the PID number programmatically should obtain the PID number from the registry.
2. The same PID number can be found at the bottom of the IP.21 Manager after double clicking on a running task. This number also corresponds to the PID number displayed in the Windows Task Manager (Processes tab).
Steps:
1. Double click on a particular running task in the InfoPlus.21 Manager.
2. Note the Process Id number (PID) which appears at the bottom of the InfoPlus.21 Manager.
3. Open Windows Task Manager and click on the Processes tab.
4. Sort the processes by the PID number.
5. Find the task (or process) number noted earlier (in IP.21 Manager) and see which task corresponds to it.
Keywords:
References: None |
Problem Statement: Administrator tool opens and it's empty | Solution: Check the version of the comcat.dll that resides in the %WINDIR%\System32 directory (very likely to be c:\winnt\system32). If it is V5.0, this version is actually an incompatible Win95 .dll, that has managed to get onto NT systems when what we call third party software has been installed on that machine. In addition to the comcat.dll v5.0, a comcat.dll v4.71 dated 10/15/98 has also been found to be incompatible. The comcat.dll v4.71 dated 4/30/99 is known to be compatible.
Attached to thisSolution is a copy of the comcat.dll for NT (version 4.71 22KB dated 4/30/99)
The following 4 steps actually come from a Microsoft Knowledgebase Document:
http://support.microsoft.com/support/kb/articles/Q254/9/36.ASP
Create a backup copy of the existing version of the file from the %WINDIR%\System32 directory. (very likely to be c:\winnt\system32)
Unregister the existing version of the Comcat.dll file as follows: regsvr32 /u comcat.dll
Copy the older version(4.71) of the Comcat.dll file to the %WINDIR%\System32 directory.
Register the older version as follows: regsvr32 comcat.dll
At this point, you should be able to re-open the Administrator tool and see the desired information.
Keywords: comcat.dll
empty
administrator
References: None |
Problem Statement: I was using a property method (such as WILS-GLR) that had a liquid reference state. I entered temperature-dependent parameter data on the PROPERTIES | PARAMETERS | PURE COMPONENT | CPLDIP-1
However, when I added the WILSON property method and deleted the WILS-GLR property method from the PROPERTIES | PROPERTY METHOD object manager, the entire CPLDIP-1 property disappeared from the simulation. | Solution: The Aspen Plus GUI determines what parameters it needs based on the property methods that you have selected. Given the property methods, it figures out the models used and from the models, the parameters needed by the model. Therefore, if you change the route or model such that a given model is not used anymore, then its parameters will not be needed and will be deleted.
This means that if you get rid of the model that uses these parameters, its parameters will disappear. A work around is to create another property method and modify it instead of modifying the one that uses the model.
This works as designed.
Keywords: None
References: None |
Problem Statement: How do you calculate the wet bulb temperature for a stream? | Solution: The attached file illustrates a model to estimate the wet bulb temperature of air at a dry bulb temperature 18 C with relative humidity 35 %.
Three design specifications are created in a row in the attached model. First and second design spec is to achieve desired relative humidity at a given temperature (18 C). Relative humidity (100%) was achieved as a target spec by varying the water mole flow rate in the second mixer block ( B2). As latent heat is being supplied by the air, temperature of the outlet stream was dropped to a certain value corresponding to relative humidity 100%.
Key Words
Relative humidity, Latent Heat, Property Set, Saturation Temperature, wet bulb, temperature
Keywords: None
References: None |
Problem Statement: Create inhouse or user databanks in AspenPlus 10 and higher. | Solution: Configuring Physical Property Databanks for the Aspen Plus/FactSage/Chemapp interface For ASPEN PLUS Release 11.1 (NT/Windows 2000)
In-house databanks are created in the Aspen Plus engine directory, accessible by everyone connected to that engine with the customized user interface. For a client-server arrangement (engine on the server, GUI on client machines), the GUI on each client machine must be customized for users to to use the GUI to access the in-house databank. In-house databanks on the server can only be installed with system administrator privilege.
User databanks can be installed anywhere on a client or server by any user who has the write privilege to create the databank files. Multiple user databanks can be installed.
Databank Installation Procedures for Aspen Plus 11.1
Procedure
The following procedure applies to both inhouse and user databank. Make sure to run the commands from the Aspen Plus Simulation Engine DOS prompt.
If necessary add any newSolution phases to the FACTSOLN.TXT file.
Create a DFMS input file containing your property parameters (The file name should contain .inp such as myfile.inp) using a plain text editor such as Notepad.
Run a DFMS run in the Aspen Plus Simulation Engine window using the following command: dfms input_file report_file (example: C:> dfms myfile run1)
These two steps create databanks to be used by Aspen Engine for simulation. The steps that follow create databanks only for the GUI to display and search the components.
Create a User Interface Databank Input File (name should contain .dat such as mydata.dat), which is a plain text file.
Modify the MMTBS Driver file (tbcustom.dat) to include the User Interface Databank Input file name created in Step 3.
Update the User Interface record definition and help files to add your databank by running the command in the Aspen Plus User Interface Customization window:
mmcustom mmtbs
Verify that the databank is correctly installed, by opening the file custom.bkp located in directory \ProgramFiles\AspenTech\GUI\custom. This uses the modified RecDef file locally. Include your databank at the top of the Components Specifications Databanks Sheet and search for any component from your databank.
If Step 6 is OK, install the modified files by entering custinst at the DOS prompt.
Example
The following is an example of creating an in-house databank and a user databank for the ChemApp Fact\Sage Interface. This example adds two additional slag phases to the interface to allow for up to three immiscible liquid slag phases.
Step 0. Add any newSolution phases to FACTSOLN.TXT. (SeeSolution xxxx).
To add a newSolution phase, you need to edit the factsoln.txt file that is located in the \ProgramFiles\AspenTech\APRSystem 11.1\Engine\xeq directory.
There are two changes to make in the file:
Increment the total number ofSolutions on the second line of the file. For example, to add one additionalSolution phase, increase the total by one. To add three phases, increase the total by three.
At the bottom of the file, add the new phases. For example:
2 SLAG Slag-liquid#1 (This replaces the existing line with just Slag-liquid)
2 SLG2 Slag-liquid#2
2 SLG3 Slag-liquid#3
Step 1. Create a DFMS input file for your physical property parameters
Two DFMS input files (one for in-house and one for user databank) are created (using any plain text editor). For additional help on DFMS input file, refer to the Aspen Plus Physical Property Data manual, or using the online help (go to HELP Menu/Help Topics/Contents/Properties/Physical Property Data/ Databanks/Using DFMS to Manage Databanks.)
The first section of the DFMS file is the NEW-COMP section. In the case of FACTPCD components, the structure is xxxxxx:yyyy, where xxxxx is the name FactSage understands and yyyy is the phase (e.g. SLG2). The total length of a component name is limited to 32 characters and the yyyy section is limited to 4 characters. Note that yyyy must be the same as the 4 character name in FactSoln.txt. The second field is an alias - limited to 12 characters. This is used primarily to indicate different numbers for different phases of the same molecule.
The second section is in the PROP-DATA section. A new component would require one line in each section. The first field is PVAL. The second field is the component name enclosed in single quotes. The third sections is the molecular weight. Everything after the molecular weight is the same for all components to be used with the Aspen Plus/FactSage/Chemapp interface.
For inhouse databank, the following DFMS input file with file name INHSFACT.INP is created with Notepad:
; DFMS input file for creating an in-house databank
;FILE NAME: INHSFACT.INP
;
FILE INHSPCD INHSPCD NEW
WRFILE INHSPCD
;
NEW-COMP
''CAO:SLG2'' ''CAO:SLG2'' /
''CAO:SLG3'' ''CAO:SLG3'' /
''SIO2:SLG2'' ''SIO2:SLG2'' /
''SIO2:SLG3'' ''SIO2:SLG3'' /
''AL2O3:SLG2'' ''AL2O3:SLG2'' /
''AL2O3:SLG3'' ''AL2O3:SLG3''
NEW-PROP MW 1 / DHFORM 1 / DHSFRM 1
PROP-DATA
PROP-LIST MW 0 / DHFORM 0 / DHSFRM 0
PVAL ''CAO:SLG2'' 56.0774 / -9999 / -9999
PVAL ''CAO:SLG3'' 56.0774 / -9999 / -9999
PVAL ''SIO2:SLG2'' 60.0843 / -9999 / -9999
PVAL ''SIO2:SLG3'' 60.0843 / -9999 / -9999
PVAL ''AL2O3:SLG2'' 101.96128 / -9999 / -9999
PVAL ''AL2O3:SLG3'' 101.96128 / -9999 / -9999
PRINT-DIR INHSPCD
PRINT-DATA INHSPCD
END-INPUT
Alternatively, a user databank could be created:
; FILE NAME: USRFACT.INP
;
FILE USRPP1A USRFACT NEW
WRFILE USRFACT
NEW-COMP
''CAO:SLG2'' ''CAO:SLG2'' /
''CAO:SLG3'' ''CAO:SLG3'' /
''SIO2:SLG2'' ''SIO2:SLG2'' /
''SIO2:SLG3'' ''SIO2:SLG3'' /
''AL2O3:SLG2'' ''AL2O3:SLG2'' /
''AL2O3:SLG3'' ''AL2O3:SLG3''
NEW-PROP MW 1 / DHFORM 1 / DHSFRM 1
PROP-DATA
PROP-LIST MW 0 / DHFORM 0 / DHSFRM 0
PVAL ''CAO:SLG2'' 56.0774 / -9999 / -9999
PVAL ''CAO:SLG3'' 56.0774 / -9999 / -9999
PVAL ''SIO2:SLG2'' 60.0843 / -9999 / -9999
PVAL ''SIO2:SLG3'' 60.0843 / -9999 / -9999
PVAL ''AL2O3:SLG2'' 101.96128 / -9999 / -9999
PVAL ''AL2O3:SLG3'' 101.96128 / -9999 / -9999
PRINT-DIR USRFACT
PRINT-DATA USRFACT
END-INPUT
Since Aspen Plus allows multiple user databanks, one can create a second or third user databank if so desired:
Step 2. Run a DFMS Run
For in-house databank with the DFMS input file inhsfact.inp, run the DFMS Run as follows:
C:> dfms inhsfact run1
which should be executed from the directory where inhsfact.inp file resides (preferably your working directory). The run creates a databank called inhspcd.dat in system directory (\ProgramFiles\AspenTech\APRSystem 11.1\Engine\dat) and a report file run1.rep in the current directory.
For user databank with the DFMS input file usrfact.inp, you may enter the following:
C:> dfms usrfact run2
This will generate a file USRPP1A.DAT and run2.rep in the current directory. You may inspect run1.rep and run2.rep for dfms run messages. To create a second user databank, enter:
C:> dfms filename run3
The DFMS run is sufficient if one runs Aspen Plus from the input language. For GUI, one must go through the following steps (Starting from Step 3) for further customization.
Step 3. Create a User Interface Databank Input File.
The User Interface Databank Input file defines the databank location and lists the aliases and long names for the components in your databank. The file name should contain .dat. For in-house databank in the current example, the following shows the User Interface Databank Input File with a file name inhouse.dat:
/* all input starts at column 1 */
/* file name: inhsfact.dat */
DBANK ADD INHSPCD
NONE
SYSTEM
CAO:SLG2 CAO:SLG2 0
56.0774 0.1E36 0.1E36 *
Slag
CAO:SLG3 CAO:SLG3 0
56.0774 0.1E36 0.1E36 *
Slag
SIO2:SLG2 SIO2:SLG2 0
60.0843 0.1E36 0.1E36 *
Slag
SIO2:SLG3 SIO2:SLG3 0
60.0843 0.1E36 0.1E36 *
Slag
AL2O3:SLG2 AL2O3:SLG2 0
101.96128 0.1E36 0.1E36 *
Slag
AL2O3:SLG3 AL2O3:SLG3 0
101.96128 0.1E36 0.1E36 *
Slag
Note that some additional physical properties (such as molecular weight, boiling point, etc.) are entered here to enable its search in Aspen Plus user interface. (Note: these data entered here are not used for simulation. They are used only for component search and display in GUI. Any data for simulation must be entered in the DFMS input file)
For the user databank, a plain text file called user1.dat is created as follows:
/* all input starts at column 1 */
/* file name: usrfact.dat */
DBANK ADD MYDATA1
USRPP1 USRFACT
USRPP1A.DAT
CAO:SLG2 CAO:SLG2 0
56.0774 0.1E36 0.1E36 *
Slag
CAO:SLG3 CAO:SLG3 0
56.0774 0.1E36 0.1E36 *
Slag
SIO2:SLG2 SIO2:SLG2 0
60.0843 0.1E36 0.1E36 *
Slag
SIO2:SLG3 SIO2:SLG3 0
60.0843 0.1E36 0.1E36 *
Slag
AL2O3:SLG2 AL2O3:SLG2 0
101.96128 0.1E36 0.1E36 *
Slag
AL2O3:SLG3 AL2O3:SLG3 0
101.96128 0.1E36 0.1E36 *
Slag
For the second user databank, an additional file could be created:
Note that:
MYFACT1 is the databank name that will appear in the Aspen Plus user interface under (/data/components/specifications/databanks)
USRPP1 is the type of databank specified in the DFMS input file (See Step 1)
USRFACT is the password used for uniquely identifying the databank in the DFMS input file (See Step 1). (useful when you have multiple databanks). The password here must match that in DFMS input file.
USRPP1A.DAT and USRPP1B.DAT are the files generated by running DFMS (See Step 2).
Step 4. Modify the MMTBS Driver File
Edit the file tbcustom.dat in \Program Files\AspenTech\APRSystem 11.1\GUI\custom directory to add an INCLUDE statement between the other databanks include statements, as shown below.
INCLUDE PURECOMP.DATINCLUDE C:\MYSIMU~1\INHOUSE.DATINCLUDE PURE856.DATINCLUDE AQUEOUS.DATINCLUDE INORGANI.DAT...
For user databank in the current example, the Include statement should looks like this:
INCLUDE C:\MYSIMU~1\USER1.DAT
If the second user databank, one needs to add one additional line:
INCLUDE C:\MYSIMU~1\USER2.DAT
Note that the complete path must be given in the Include statements if the user interface input file is not in the \Program Files\AspenTech\APRSystem 11.1\GUI\custom directory. Here we assume the user interface input files reside in the directory My Simulations.
Step 5. Update the User Interface Record Definition Files.
In the Aspen Plus User Interface Customization window, from the \Program Files\AspenTech\APRSystem 11.1\GUI\custom directory run the command:
C:> mmcustom mmtbs
to update the User Interface record definition and help files to reflect your changes. This may take a few minutes.
Step 6. Verify the databank installation
To verify that the databank is correctly installed, launch ASPEN PLUS and open the file custom.bkp located in the \ProgramFiles\AspenTech\APRSystem 11.1\GUI\custom directory. This starts the user interface locally to use the modified RecDef file. Otherwise the unmodified system copy of the RecDef file is used.
Go to the Components/Specifications/Databanks Sheet and you will find inhspcd (if inhouse databank is installed), or MYFACT1 (if a user databank is installed) are listed under the available databanks field. Move them over to the selected databanks field. Click on the Components Find button on the Components Specifications Selection Sheet and search for any component from your databank. Make sure it can be found.
Step 7. Install the Modified Files
In the Aspen Plus User Interface Customization window, from the \ProgramFiles\AspenTech\APRSystem 11.1\GUI\custom directory, enter
C:> custinst
Since the inhouse databank, i.e., the file generated by DFMS and called inhspcd.dat, is located in the system directory, it is located by Aspen Plus automatically. However, for user databanks (USRPP1A.DAT and USRPP1B.DAT), these files may locate anywhere on your PC. To allow Aspen Plus to find these files, the path to these files must be given under Run/Settings. For example, for user databank USRPP1A.DAT generated by DFMS and located in c:\my simulations, one must add the following in the run/settings/pp1a field:
c:\My Simulations\USRPP1A.DAT
For USRPP1B.DAT, a similar statement must be added in the pp1b field. Then during the simulation, Aspen Plus will attempt to retrieve property data from the user databank files in the specified directory.
Keywords: chemapp
fact
sage
interface
References: s
Aspen Plus HELP Menu / Help Topics / Contents / Properties / Physical Property Data / Databanks / ASPEN PLUS Databanks
Aspen Plus HELP Menu / Help Topics / Contents / Properties / Physical Property Data / Databanks / Using DFMS to Manage Databanks
System Management Version 11, Chapter 4: Configuring Physical Property Databanks |
Problem Statement: How do you change the Stream Summary or Stream Table so that only the components of interest are listed? This may be desired when there are components of zero flow in all streams. | Solution: In 2006 and higher, rows for undesired components in the Custom Stream Summary can be selected and hidden.
In 2004.1 and earlier, the list of components on the Stream Summary form can be reduced by creating a new customized Stream Summary Format File (TFF) file and specifying it on the Format field of the Streams form. Files with the TFF extension (filename.tff) are used by Aspen Plus to format the Stream Results forms. For more information on TFF files refer to the Aspen Plus User Guide.
The steps are as follows:
1. Copy one of the existing .TFF files such as Full.TFF in the Aspen Plus\GUI\xeq directory to the working directory where the simulation is locate.
2. Rename the file to whatever name desired for the Format.
3. Edit the new TFF file and change the line that reads:
display all
to
display only COMPS=cnamelist
where cnamelist is a list of components you want to see in the Stream Summary. Separate each component by spaces. Specify the name of the TFF file (without extension) in the Format field on the Stream Summary results form.
4. Open the simulation and run. Select the new Format from the drop-down list on a Stream form.
The above procedure will not allow you to reorder the list of components shown on the Stream forms. To reorder the components you must change the order of the components on the Components\Specifications\Global sheet and rerun the simulation.
Note:
With a ?display only comps=cnamelist? line, none of the stream properties such as temperature, pressure, or enthalpy will appear since these are not properties of the specified components. In order to view these properties, either add a second loop or use a different .tff.
If you have a ?display all? line for a second loop, then all properties for all components will be displayed in addition to the properties that are displayed for the subset of components. For example, you would have moleflow for C1 C2 and C3 plus moleflow for all of the components. Alternatively, you can use a display only line to display a set list of properties.
If there is no display all line and additional prop-sets are requested on the Report Options | Stream sheet, they will not be displayed unless they have a prop statement in the .tff.
If a property is not requested on the Report Options | Stream sheet, it will not be displayed even if there is a prop statement because it is not calculated by the engine and not in the summary file.
Example:
Here is the text for a .tff file that prints the flows and fractions for only components C1 C2 and C3 and then prints a set of properties such as temperature, pressure and enthalpy for the entire stream.
title=yes
stream-id-label=yes
source-label=yes
dest-label=yes
phase-label=yes
begloop substream=all
display only COMPS=C1 C2 C3
prop moleflow prop-label=Mole Flow
prop massflow prop-label=Mass Flow
prop vlstd prop-label=Liq Vol 60F
prop molefrac prop-label=Mole Frac
prop massfrac prop-label=Mass Frac
prop vlstdfr prop-label=LiqVolFrac60F
endloop
begloop substream=all
display only
prop temp prop-label=Temperature
prop pres prop-label=Pressure
prop moleflmx prop-label=Total Flow
prop massflmx prop-label=Total Flow
prop volflmx prop-label=Total Flow
prop vlstdmx prop-label=Liq Vol 60F
prop vfrac prop-label=Vapor Frac
prop lfrac prop-label=Liquid Frac
prop sfrac prop-label=Solid Frac
prop hmx prop-label=Enthalpy
prop smx prop-label=Entropy
prop rhomx prop-label=Density
prop mwmx prop-label=Average MW
endloop
Keywords: stream-table
stream-summary
References: None |
Problem Statement: How to change the standard condition of standard volume?
My company uses 68 F as the standard condition. Is it possible to change the standard conditions? | Solution: If your reference temperature is 0 C or 60 F, you can just choose a units-set to get the appropriate reference temperature. TheSolution document 105245 contains the list of the reference temperatures with respect to different units.
If you want to change your reference temperature use VVSTDMX or VVSTD in your prop-set, and specify your reference temperature and/or pressure on the Qualifier tab. This is for standard vapor volume only; you cannot change the reference temperature for the standard liquid volume from 60 F.
Keywords: Standard, standard condition, change, temperature
References: None |
Problem Statement: In a file containing a sensitivity analysis, the outlet stream results are different than those specified in the input forms. I didn't think that the sensitivity analysis should change the base case. | Solution: This is due to the Execution options in the Sensitivity's Input | Optional sheet which has Execute base case first or Do not execute base case.
The Execution options on the Optional sheet of a Sensitivity effect when the base case is executed, not just the order the results are printed in the report. Execute base case last is the default. In this case, blocks and streams will be left with the values on the input forms. For the other options, Execute base case first and Do not execute base case, blocks and streams will be left with values from the last row of the sensitivity.
Variables changed by a Sensitivity will remain at their last values at the start of the next run if you do not reinitialize the problem; this may be different than the base case values if you do not run the base case last. If you continue to modify the problem and the Sensitivity manipulated variables are not changed, these variables will retain their last values from the Sensitivity (rather than values previously specified on other forms) until otherwise changed or the problem is reinitialized.
Keywords: sensivitity
References: None |
Problem Statement: Different results are obtained depending on if my variable NGQ is defined as a parameter or if it is not defined and only used in a Calculator block. Why does defining the variable make a difference? | Solution: This is an idiosyncrasy of Fortran. There are two type of variables: INTEGER and REAL*8 (DOUBLE PRECISION).
For a DEFINEd variable (a variable specified on the Define sheet), the variable type is determined from the type of variable with which it is associated. Unless you are accessing an integer parameter such as the number of stages in a column, the variable type is REAL*8.
For a local variable (not DEFINEd) without explicit typing in the Fortran code, the variable type is an INTEGER if the name of the variables starts with the letters I to N. So without a DEFINE, NGQ is an INTEGER. With DEFINE, NGQ is a DOUBLE PRECISION REAL. Users should add an explicit variable declaration for variables that are not DEFINEd.
Keywords: None
References: None |
Problem Statement: The HeatX input form gives a Value is out of range error message when a negative value for the Exchanger Duty specification is entered: | Solution: Although many unit operations in Aspen Plus will allow both negative and positive heat duties, the HeatX block will only accept a positive value. This is because there is zero net heat produced in the HeatX - all the heat released by the hot stream is absorbed by the cold stream.
Even if you are trying to match a condenser duty, say in a RadFrac block, remember to always enter the absolute value of the heat duty (i.e. always enter a positive value for Exchanger Duty).
Keywords: heatx, exchanger duty, out of range
References: None |
Problem Statement: Retrieve Parameter Results does not import any data | Solution: In version 2006, we upgraded the warning to error for PC-SAFT missing parameters to force the user to provide parameter values for all components defined in the simulation.
If you have other components that have missing parameters, you need to perform a data regression to get the PC-SAFT parameters using component vapor pressure and saturated liquid density data.
This is by design. Please always check the control panel if you do not see results after a Retrieve Parameter Results step.
Keywords: None
References: None |
Problem Statement: How to generate B_LTEMP and B_VTEMP when exporting the Aspen Plus simulation to an XML file | Solution: The definition for B_LTEMP is the temperature of the liquid to a stage and B_VTEMP is the temperature of the vapor to a stage. To get these results into XML, you need to do two things:
1. Enable the option Include Hydraulic parameters on the Report form of the RadFrac block
2. Ensure that a compatible version of Aspen Dynamics is installed. For instance, if you are using Aspen Plus 2006.5 then Aspen Dynamics 2006.5 needs to be installed.
Keywords: B_LTEMP
B_VTEMP
RADFRAC
Hydraulic parameters
References: : CQ00325244 |
Problem Statement: How can I design a boiler with combustion in one side? | Solution: There are two possible approaches to modeling a boiler with combustion in one side.
Approach 1: You can use a reactor block for the combustion reactions and a heater block for the feed water. Connect these two blocks with an energy stream. Note that you may want to use different physical property methods in each block.
Approach 2: Use a reactor block for the combustion reactions. Use a HeatX block where one side contains the feed water and the other side contains with the combustion products from the reactor block. Again, it may be useful to use different physical property methods in each block, and possibly on the two sides of the HeatX block.
Keywords: Boiler, combustion
References: None |
Problem Statement: For Cosmo-SAC property method. what parameter user need to enter to run? | Solution: The COSMO-SAC model requires three parameters for each component:
Component volume, V
Component surface area, A
Component sigma profile, p (sigma) where p is a function of component surface charge density (sigma).
All three parameters should be carried out by the same quantum mechanical calculation for the consistency. In theory, p should be normalized as follows:
sumi [pi (sigmai)] = 1, (i = 1, 2, ..., very large number or infinity)
In practice, only a limited number of points for component surface change density are used for the sigma profile calculation where the most common choice is 51 points. Also for convenience, the value of the sigma profile is reported as a so-called effective sigma profile which is the component surface area times the sigma profile at each surface change density.
The implementation in Aspen Plus for COSMO-SAC adapts the effective sigma profile approach so that it requires only two parameters, component volume and sigma profile. The component surface area will be calculated as follows:
A = sumi pi(sigmai), i = 1, 2, ..., 51
A quantum mechanical calculation should give you all three parameters for each component. Then if necessary, you can convert the original sigma profile form to the effective sigma profile form as defined above for Aspen Plus.
If your COSMO output is from a program like Gaussian, the program should provide you the details on how to calculate these three parameters for each component from the COSMO output. The procedure may vary depending on how the quantum mechanical calculation is carried out. Aspen Plus cannot provide such a procedure for conversion.
Keywords: cosmo-sac
sigma profile
quantum mechanical
References: None |
Problem Statement: Is it possible in Aspen Plus to simulate a reactive heterogeneous distillation using a catalyst? | Solution: It is not supported directly. If your reaction rate is computed on a per catalyst amount basis, then you enter the catalyst hold-up amount in the Hold-up in the Reactions | Hold-up sheet.
The help for RateSep (rate-based mode of RadFrac) also applies for the equilibrium mode of RadFrac. The only difference as far as reaction is concerned is that you always specify holdup (as holdup or residence time). For the heterogeneous reaction, the holdup would be catalyst amount and the reaction rate is computed on per catalyst amount basis.
We do not handle heterogeneous reactions DIRECTLY. The user is responsible to come up with rate expression/routine for computing reaction rate using the overall liquid composition (i.e. pseudo homogeneous reaction).
On the Reactions | Hold-up sheet, if the reaction rate is in mass basis, you HAVE TO specify holdup in mass basis otherwise you get wrong result.
Keywords: None
References: None |
Problem Statement: After adding a user or inhouse databank and customizing the user interface on one computer, is there an easy way to customize other computers? | Solution: There is no need to customize each PC. After completing the customization of an inhouse or user databank in a new version of Aspen Plus on one PC, it is possible to just copy the two files listed below to another machine which also has the new version installed.
Copy:
1. The databank files used by the engine
- For an inhouse databank, copy inhspcd.dat which resides in the \Program Files\AspenTech\APrSystem xxxx\Engine\dat directory.
- For a user databank, the *.dat file needs to be copied to the new machine. The location of the user databank is specified in Run\Settings for the simulation.
2. The GUI customization files
- Copy the system definition file recdef.apr which resides in the \Program Files\AspenTech\APrSystem xxxx\GUI\xeq directory.
Note: Save a copy of the original recdef.apr to be safe. Once the recdef.apr has been replaced, the GUI will be customized, and old .apw file will no longer be compatible. All files should be saved in backup (.bkp) format before replacing the recdef.apr file.
Keywords: user databank
inhouser databank
References: None |
Problem Statement: How do you create a pop-up window in Aspen Plus? | Solution: If you want to be informed via a pop-Up Window if something occurs (an error, or the end of the simulation),
add the following to your Fortran code at the appropriate location:
F CHARACTER msg*70
C ---
F msg = Hello World!
F call system('msg * /time:0 /w '//msg)
This trick works also with the batch mode, or if you run your input file from command line.
Msg is a part of MS-XP-Operating system, - if you work interactive, the simulation stops at this point.
Contributed by Stefan Pofahl
Keywords: None
References: None |
Problem Statement: How do I perform Property Analysis or Flowsheet run after completing a standalone data regression (DRS) of UNIFAC-PSRK parameters? When I try the results are different. | Solution: When a Data Regression of UNIFAC parameters is performed under a Data Regression run type, only the interaction between one group in one main group and one group in any other main group is regressed. Then regressed UNIFAC parameters are copied into the forms such as UNIFPS-1 (Properties|Parameters|UNIFAC Group Binary|UNIFPS-1). All other groups within main groups are automatically equated to the regressed values (Table 1).
Table 1. UNIFAC-PSRK parameters, system: Propane-Hydrogen Sulfide.
Group IDi
1010
1015
3860
3860
Group IDj
3860
3860
1010
1015
Element 1
893.01
893.01
742.31
742.31
Element 2
-3.1342
-3.1342
-5.7074
-5.7074
Element 3
0.0013022
0.0013022
0.012651
0.012651
After run type is toggled to Property Analysis or Flowsheet, the run is started over. In the Property Analysis or Flowsheet runs, the parameters are not equated. Therefore, users should copy regressed values to other groups in UNIFPS-1 folder (Figure 1).
Figure 1. UNIFPS parameters, GROUP ID: G1 (1010), G2 (3860), G3 (1015).
User then can proceed to perform the Property Analysis or Flow sheet run type.
Keywords: DRS, UNIFAC-PRSK, Property Analysis or Flow sheet run type after DRS.
References: : CQ00450130 |
Problem Statement: Some Sulzer packings such as Sulzer high capacity packings MELLAPAK 202Y and 352Y are not in Aspen Plus. Can they be added? | Solution: We have an agreement in place with Sulzer that states, in essence, that they will supply all models and information about their packings. Unfortunately what they have supplied us does not include all of their packings. For example, for V8.0, they have not provided us any information on 202Y or 352Y. As they provide us information, it will be added to the product.
Keywords: None
References: : CQ00382516 |
Problem Statement: In the pdserver.out file, the following error appears (if you are using MS SQLserver with Batch):
DB-Library error: 10025
Possible network error: Write to SQL Server Failed. Invalid connection. r21_exec_immediate: error in call to dbsqlexec
r21_exec_immediate: Insert into event_db..event21 ( eventid,t1,t1gmt,msecs,tag,value, status,type,severity,condition,area,username,comment_flag,text,key1,key2,key3,key4,key5, key6,key7,key8,key9,key10 ) values ( 1361794,''05 Aug 01 12:46:13'',997008373,900,'''', 0.000000,0,22,1,0,6,''bcutask'',0,''V6-02 WASH'',0,0,0,0,0,0,0,0,0,0 ) r21_terminate
The following is a database error code. Consult your
database administrator for help in resolving this problem.
See your database documentation for more details.
DB-Library error: 10005
DBPROCESS is dead or not enabled. Check error code and consider adding it to the retry
error code file specified by the retryfile=file_name
entry in the R21CONFIG section of the $CIM21_CONFIG
file. Consider adding the entry to the file located
in the $r21/dat directory. | Solution: Microsoft error: BUG# 9907 (4.21) After receiving an error fatal to a dbprocess, such as a 10025 Write to SQL Server Failed, a continual stream of 10005 DBPROCESS is dead or not enabled errors is received by the error handler.Solution Upgrade API MS SQLserver version.
The problem has to do with the version of MS SQL Server Programmers ToolKit. This is not an Aspentech problem but a Microsoft issue. You need to talk to you database administrator to load a version of the toolkit that does not crash. Below you will find the link to Microsoft''s website that details the bug the customer is seeing:
http://support.microsoft.com/support/kb/articles/Q113/5/27.asp
BUG: Calling dberrhandle in Error Handler Causes Recursion
The information in this article applies to:
Microsoft SQL Server Programmer''s Toolkit, version 4.2
BUG# 9907 (4.21)
SYMPTOMS
After receiving an error fatal to a dbprocess, such as a 10025 Write to SQL Server Failed, a continual stream of 10005 DBPROCESS is dead or not enabled errors is received by the error handler. CAUSE
Calling dberrhandle(NULL) inside of the DB-Library (DB-Lib) error handler, when it is called due to a dbprocess killing error, like 10025 or 10005, will cause the error handler to be called again with a 10005 error. WORKAROUND
Applications should call dberrhandle() within their error handlers only if the following condition is true:
dbproc != NULL && !DBDEAD( dbproc )
This behavior does not occur in versions of DB-Library prior to version 4.21.
Keywords: DB-Library error: 10005
DB-Library error: 10025
PDserver crash
InfoPlus.21
References: None |
Problem Statement: I am doing a Property Analysis for a mixture by varying the mole fraction for two out of four components in the simulation. Why am I getting the following error:
ERROR WHILE GENERATING PROP-TABLE: PT-1. SUM OF BASIS-FRACS IS GREATER THAN ONE. MOLE FRACTIONS WILL BE NORMALIZED TO SUM TO 1.0? | Solution: When doing Property Analysis for a mixture, its composition needs to be specified as input either by referring to a flowsheet stream or specifying the flowrate for each component specifically. If more than one of the adjusted variables is a fraction, the user might get the following error:
ERROR WHILE GENERATING PROP-TABLE: PT-1. SUM OF BASIS-FRACS IS GREATER THAN ONE. MOLE FRACTIONS WILL BE NORMALIZED TO SUM TO 1.0.
The reason for this error can be illustrated by a simple example. For a mixture of equal mole fractions of component A, B, C and D, if the mole fractions of component A and B are set to be adjusted variables both changing from 0 to 1 with an increment of 0.1, Aspen Plus will execute the Property Analysis at all possible combinations of the adjusted variables. For this case, there will be 121 combinations, even though not all of them are physically valid. For the case of 0.5 mole fraction of component A with 0.7 mole fraction of component B, the sum of the mole fraction is greater than one, which triggers Aspen Plus to give the above error and normalize the sum to 1.0.
Even though component C and D are not set as adjusted variables in the above example, their compositions are also changed automatically for each combination. For example, for the case of 0.1 mole fraction of A and 0.7 mole fraction of B, the mole fraction of C and D will be calculated based on the portion left by the adjusted variables according to the original compositions of C and D in the base case:
Mole fraction of C =
Similarly,
Mole fraction of D =
Keywords: Property analysis, composition
References: None |
Problem Statement: When copying and pasting portions of my Aspen Plus flowsheet to Microsoft Word or Excel, the stream and block labels are too small to read. | Solution: This can be adjusted using the label size scale factor which controls the size of block and stream IDs for printing. Scaling affects the printed or copied sized of labels, but not their size on the Aspen Plus flowsheet itself. When Global Data is on, this factor also controls the size of the displayed global data values and legend box. This is a relative factor. Use a larger value for larger IDs and global data values. A factor between 2-3 is generally appropriate when printing relatively large flowsheets
To adjust the label size
1. Go to Tools | Options | Flowsheet tab and increase the label size scale factor. The default value is 1. Change it to a larger number.
2. Select what you want to copy from the flowsheet, and then choose Edit | Copy.
3. In your Word or Excel file, choose paste. The flowsheet with the adjusted label sizes will appear. You may have to try a few different scale values until you get the labels the size you want.
Note: You must be zoomed in enough on the Aspen Plus flowsheet for the labels to be visible. If the labels are not visible on the flowsheet before the copy, then the scaling will not be applied and they will not be visible in Word or Excel.
Keywords: Flowsheet, Excel, Word, Scale, Label
References: None |
Problem Statement: Can I use the equation oriented run mode to adjust kinetic parameters using plant data? | Solution: This is a simple RCSTR with one POWERLAW reaction. The mole fraction of component BBB is measured in the outlet stream of the reactor B1, and the pre-exponential factor for the reaction is adjusted to make the difference between the measurement and the model result as close as possible (minimization of the squares of the differences, weighted by the standard deviation of the measurement).
In the equation oriented (EO) Configuration, EO Variables, I've set R-1.RXNPARAM(RXN1).PRE_EXP to be Reconciled. This means it is constant in all run modes excepted data reconciliation, in which it is calculated.
In EO Configuration, Objective, we have created an objective function O-1, which specifies the measured value of the concentration (say 0.95) and the standard deviation (say 0.01) for B1.Z(BBB) (mole fraction in outlet of reactor).
In the control panel, the run mode is set to EO, Reconciliation, with objective function O-1. This will adjust the pre-exponential factor to 0.00133937. This is powerlaw-eo-ex1.bkp.
For on-line applications or larger applications, we don't recommend changing the specs directly in the EO variable form, and we don't recommend entering the data in the objective function. Instead we recommend using a MEASUREMENT block. The MEASUREMENT block (in Manipulators tab of model library) will store the plant data. A new variable OFFSET is calculated, OFFSET = PLANT - MODEL. The MODEL variable needs to be connected (via the MEASUREMENT block) to the calculated variable (in this case the composition). Finally a SPEC-GROUP is created to set the pre-exponential factor to be Reconciled. This is illustrated with the file powerlaw-eo-ex2.bkp.
If you have multiple test run data, you will need to create as many instances of your flowsheet as the number of test run sets.
Keywords: None
References: None |
Problem Statement: How do you change the font size of the Global Data on the process design flowsheet (PFD)? | Solution: You can change the font size of the simulation data displayed in the Graphical User Interface in Aspen Plus by going to the Tools menu Options | Styles sheet and changing the Label Font for block and stream labels. This font is also used for the global data. Changing this value will change the font for block and stream labels and global data for the entire flowsheet. You cannot change anything individually. The font change will also show in the printed version.
The Label size scale factor on the Tools menu Options | Flowsheet sheet only affects the size of the labels in the printed copy. It does not change the size of the labels viewed on the computer.
Keywords: None
References: None |
Problem Statement: What to do when simulation of rupture disks end with integration errors? | Solution: Often when simulating a rupture disk using a the Pressure Relief option, the simulation will proceed through the various time steps and after bursting the rupture disk will end with an integration error. The most common cause of this situation is that once the the disk has burst the pressure within the vessel reduces to the discharge pressure instantaneously. If the calculations continue to the next time step (because there is a tail pipe specified or the simulation time is longer than the time to burst) there may be a negative pressure differential across the rupture disk forcing the vent flow to reverse its flow direction back into the vessel. Aspen Plus stops the integration and issues an error at this point.
The best work around is to specify a STOP CRITERIA on the Operations sheet to stop the simulation at a pressure slightly above the discharge pressure.
The input language for such a stop criteria assuming a discharge pressure of 14.7 psia would like this:
STOP CRITNO=1 LOCATION=VESSEL VARIABLE=PRES VALUE=15 &
SPEC-TYPE=FROM-ABOVE
It may be necessary to size a disk inspite of the integration error and might result in inadequate relief systems being designed by those not familiar enough with pressure relief sizing.
The integration error is encountered when the pressure builds due to the temperature rise and the majority of the vessel pressure is exerted by the expansion of the trapped inert pad gas and not the vapor pressure of the liquid in the vessel. Vessel pressure rises and then immediately falls off because the liquid phase has not reached the boiling point by the time the disk bursts.
A designer can confirm this by raising the stop criteria as high as necessary to halt the error, then they can check the temperature at burst. If the mix is not yet at the burst pressure, then the sizing run should be repeated starting with an open vent or by raising the starting temperature by the shortfall in temperature between the mixture bubble point and the previously determined vessel temperature plus 1 to 10 degrees to assure the vessel reaches a high enough internal pressure at the time of burst.
Actual time to temperature can be done by manual extrapolation.
Keywords: pres relief
pres-relief
References: None |
Problem Statement: What is the difference between the XAPP and XAPP2 property sets for electrolyte apparent approach composition? | Solution: Apparent component flows and fractions can be calculated in multiple ways for some true component simulations when the chemistry contains STOIC reactions. For instance, if Na+, K+, Br-, Cl-, NaBr, NaCl, KBr, and KCl are in the simulation, KBr + NaCl can be represented equivalently as KCl + NaBr.
For FAPP, XAPP, WAPP, and WXAPP, the apparent components are created in the order they appear in the component list. In the list above, as much NaBr as possible would be created, then NaCl, then KBr, and finally KCl.
For FAPP2, XAPP2, WAPP2, and WXAPP2, the apparent components are created in the order they appear in reactions on the Reactions | Chemistry form. Again, as much as possible of each component is created when its reaction is considered.
The order of the reactions has impact only on the Equilibrium (STOIC) reactions, not the Dissociation (DISS) ones. The Dissociation reactions are impacted by the order in the component list for either XAPP or XAPP2.
Keywords: electrolyte, ions
References: None |
Problem Statement: What are the sign conventions of Heat or Duty? | Solution: The sign conventions for Heat (or Duty) information streams is as follows:
A block is receiving heat: positive
A block is losing heat: negative
An inlet heat stream is adding heat to a block: positive
An inlet heat stream is actually removing heat (instead of adding) from a block: negative
An outlet stream is removing heat from a block: positive.
An outlet stream is actually adding (instead of removing heat): negative.
The direction of the stream is in the direction of information. Heat (or Duty) information flows into a block as the inlet stream and out of the block as the outlet stream. The sign of duty indicates if the heat is removed or added.
Keywords: Heat, duty, sign, convention
References: None |
Problem Statement: Do you have a user subroutine to implement a powerlaw kinetics using activities (gamma * mole fraction) for the reactor models RBATCH, RCSTR and RPLUG? | Solution: You can use the attached subroutine. Note that this is supplied as an example only, and the code contains no error checking.
The example shows 3 reactors (RBATCH, RPLUG and RCSTR) using the user reaction, and 3 reactors with the same data but using the power law (for comparison).
The reaction is:
HAC + ETOH --> WATER + ETAC
(HAC: acetic acid, ETOH: ethanol, WATER: water, ETAC: ethyl-acetate)
The reaction rate is assumed to be:
r = k * exp(-Ea/R (1/T - 1/To)) * activity(HAC)^0.9 * activity(ETOH)^0.8
where k = 0.001, Ea = 20000000 J/kmol and To = 300K
The kinetic parameters are specified on the user reaction subroutine sheet:
- subroutine name: USRKIN
- number of integer parameters: 1
- number of real parameter: number of components + 3 (7 in this case)
- integer parameter 1: used to select the reaction mode: 0 = reaction off, 1 = use mole fraction, 2 = use activities
- real parameter 1: pre-exponential factor (in SI units to give a rate in kmol/m3 liquid volume/sec)
- real parameter 2: activation energy (J/kmol)
- real parameter 3: reference temperature in K (used only if value is greater than 0)
- real parameter 3 + i : reaction order (exponent) for the ith components (order in Component Specifications sheet)
The source code is supplied. The example can be used with version 12.1, 2004, 2004.1 and 2006.
Keywords: None
References: None |
Problem Statement: What do I do when getting an index error like the one below in RCSTR, RPLUG, or RBATCH?
** ERROR WHILE EXECUTING UNIT OPERATIONS BLOCK: REACTOR (MODEL: RPLUG) (URE04.14)
RPLUG EXITED BECAUSE INTEGRATION FAILED. INDEX = (-1)
PROBABLE CAUSE IS INCORRECT KINETICS. CHECK RATE-CON
PARAMETERS AND MOLAR VOLUME CALCULATIONS. | Solution: This message indicates that the numerical integration engine in the reactor failed to solve the problem. Frequently this indicates an error in the input. For example, you may have entered an activation energy parameter in the wrong units making the reactions extremely fast, or you may have infeasible reactions (A -> B, zeroth order with respect to component A, with the concentration of A reaching zero). In some cases, these errors occur because the kinetics are very stiff (difficult to solve) and the default convergence parameters need to be adjusted to solve the problem. A classic example of stiff kinetics is a set of reactions involving intermediates with very low concentrations (for example A -> B -> C, first and second steps are very fast, so the concentration of B gets very low). In this situation, try using dynamic scaling with a low minimum scale factor to ensure tight convergence of the intermediate concentration. You can also try adjusting the global flash tolerance to reduce the noise in your system.
INDEX = INTEGER USED ON OUTPUT TO INDICATE RESULTS, WITH THE FOLLOWING VALUES AND MEANINGS..
INDEX = 0 INTEGRATION WAS COMPLETED TO TOUT OR BEYOND.
This indicates that there were no problems with the convergence. No action is needed.
INDEX = -1 THE INTEGRATION WAS HALTED AFTER FAILING TO PASS THE
ERROR TEST EVEN AFTER REDUCING H BY A FACTOR OF
1.E10 FROM ITS INITIAL VALUE.
To eliminate this problem try reducing the initial step size in the RPLUG or RBATCH reactor:
INDEX = -2 AFTER SOME INITIAL SUCCESS, THE INTEGRATION WAS
HALTED EITHER BY REPEATED ERROR TEST FAILURES OR
BY A TEST ON EPS. POSSIBLY TOO MUCH ACCURACY HAS
BEEN REQUESTED, OR A BAD CHOICE OF MF WAS MADE.
This value indicates that there is some noise in the system. Tightening the flash tolerance often solves this problem. The default in Aspen Plus, 1E-4, is often too loose. A tolerance of 1E-6 is generally better and more stable. Generally, more flash iterations are not needed; however, if the flash is not converging, try increasing the maximum number of iterations from 30 to a higher value such as 50 or 100. The flash convergence parameters are set globally on the Setup | Simulation Options | Flash Convergence sheet or locally on the Block Options | Simulation Options sheet.
INDEX = -3 THE INTEGRATION WAS HALTED AFTER FAILING TO ACHIEVE
CORRECTOR CONVERGENCE EVEN AFTER REDUCING H BY A
FACTOR OF 1.E10 FROM ITS INITIAL VALUE.
This value indicates that the system is difficult to solve somewhere inside the reactor. OneSolution is to try adjusting the scaling method (switch from dynamic to static or vice-versa, try adjusting minimum scale factor, convergence method, and as a last resort try adjusting error tolerance ratio to 0.2 or 0.05). Often this error comes up if you have an impossible reaction ( A -> B, not depending on the concentration of A, i.e. all the A gets used up ).
INDEX = -4 to -7
These values usually indicate a defect in the reactor model. Please contact AspenTech customer support.
INDEX = -8 INTEGRATION HALTED BECAUSE THE MAX. NO. OF STEPS (MXNST)
HAS BEEN REACHED.
This value indicates that the maximum number of iterations has been reached. Try increasing the number of integration steps, or try adjusting the scaling parameters so the reactor does not need to take so many steps.
Keywords: reactors, RPLUG, RCSTR, RBATCH, convergence
References: None |
Problem Statement: New Feature in Aspen Plus V7.2 - Flowsheet Operations Improvements | Solution: The following enhancements were made to the flowsheet operations Utility, Design Spec, Calculator, Sensitivity, Optimization, Data-Fit, and Transfer in V7.2.
Process Utility Blocks
Utility blocks now report state variables for the block and its heating/cooling value on the new Results | State Variables sheet within each block.
The utility block forms now include a State Variables tab sheet summarizing the inlet and outlet state variables for each type of process utility.
? Utility blocks now check for temperature crossover and correct direction of enthalpy flow; this can be configured on the Input | Specifications sheet to adjust the minimum temperature approach and countercurrent or co-current flow direction. You can now also specify the levels of diagnostic output.
The utility block forms now checks for temperature cross-over; use this feature to identify potential utility assignment errors in your models.
? The Model Summary Grid (formerly Block Summary Grid) now includes a sheet summarizing the process utility inputs and results.
The Utility Summary form is renamed Operating Cost Summary. The first tab on this form summarizes the heating and cooling utility costs for the model as a whole; the second sheet summarizes the utility usage for each type of heating and cooling utility.
Sensitivity Blocks
In Sensitivity block results, and on the Streams | Results | Material and Results Summary | Streams | Material sheets, you can copy the data for the entire table more quickly by clicking the empty cell in the upper left corner, to the left of the column headings. Clicking this cell copies the data values for the entire table to the clipboard immediately, but does not copy the information necessary to create live links to the results. In previous versions of Aspen Plus the copy operation could take several minutes; in V7.2 the copy operation is finished in fractions of a second.
Sensitivity blocks will now always be re-run after an input change to blocks or streams upstream from those sampled by the Sensitivity.
There is now a Plot Wizard available in Sensitivity results. This enables live-updating plots to update correctly when the number of points (in the sensitivity study) changes.
The plot wizard button shows up on the form toolbar shown here.
The wizard helps you select which variables to plot.
Calculator Blocks
There is a new COM-based version of the Excel Calculator add-in for V7.2 which replaces both the XLA version from all past versions and the COM version from V7.1, and fixes several known issues with the previous versions. This version of the add-in updates automatically, so old simulations should automatically use the new version without any special preparation required.
Variable Accessing
FORTRAN variable names for defined variables in Design Spec, Calculator, Sensitivity, Optimization, and Data-Fit may now be up to eight characters long. Formerly they were limited to six characters.
Global Parameter variables referenced in Calculator, Design-Spec, and Transfer blocks which run in Equation-oriented simulations are now connected, so that their values are truly global, as they are in Sequential modular simulations.
Convergence Blocks
In convergence blocks which can converge tear streams, several more results are shown on the Results forms.
The table in the Summary sheet is split into two views, one for tear streams and one for Design Specs and tear variables from Calculator blocks. The table for tear streams now includes the substream, component, attribute, and element (when applicable) for each variable. The table for Design Specs and tear variables shows the variable description for each variable. Both of these tables also include a variable number which is unique for each variable converged, and consistent across all the results for the block.
The table on the Tear History sheet now includes the variable number, substream, and component as additional columns.
The table on the Tear Variables sheet now includes tear variables from Calculator blocks (which were omitted by mistake in previous versions). Variables from tear streams now also include the variable number here.
Keywords: None
References: None |
Problem Statement: When will 64-bit be supported? | Solution: 64-bit is supported in V7.3. All applications will run on 64 bit computers as 32 bit applications. Only, Aspen Basic Engineering will run as a full 64 bit application.
This only applies to the operating system. Microsoft Office 64 bit versions are not yet supported.
We have no immediate plans to support multi-threading.
CQ
Keywords: None
References: :CQ0299485 |
Problem Statement: For a reaction defined to take place in the liquid phase, the amount of liquid holdup in the reactor has no effect on the amount of products of a catalytic reactor. | Solution: The setting Rate Basis on the Kinetic tab of the reaction definition is set to Reac(vol) by default. This means that the reaction is dependent on the amount of holdup in the reactor. The alternative setting is Cat(wt) which set the reaction to be dependent on the weight of catalyst in the reactor. In this case the holdup of the reactor will have no effect on the reaction.
Keywords: None
References: None |
Problem Statement: What is dirty-water? How are the calculations done? | Solution: Free-water or Dirty-water (implemented in Version 12.1 of Aspen Plus) calculations can be used when performing flash calculations or liquid-liquid equilibrium calculations on water-organic systems in which the water phase is essentially pure or has trace amounts of organic components.
The free-water or dirty-water calculations are completely rigorous, except for the assumption that the water phase is pure (free-water) or has only a trace amount of organic components (dirty-water). You can request free-water or dirty-water calculations for the entire flowsheet on the Setup | Specifications | Global sheet, for an individual unit operation block on the Block Options form for the block, or for an individual outlet stream in some blocks on the Flash-Specs form for the block.
For unit operation blocks, you can select free-water or dirty-water calculations using the Valid Phases = Vapor-Liquid or Liquid-Only flash specifications. Valid Phases = Vapor-Liquid-Liquid is reserved for rigorous three-phase calculations. If you specify Valid Phases = Vapor-Liquid-Liquid, any free-water specification is ignored; however, dirty-water calculations will override the rigorous three-phase calculations.
For water-hydrocarbon systems, free-water calculations are normally adequate. The hydrocarbon solubility in the water phase is generally negligible. In applications where the hydrocarbon solubility in the water phase is of great concern (such as in an environmental study), use dirty-water or rigorous three-phase calculations. For chemical systems such as water-higher alcohols, free-water or dirty-water calculations do not apply. Solubility of the organics in the water phase is significant. Rigorous three-phase calculations are required.
Equations
The K-value of water in the dirty-water phase is:
Where:
= The fugacity coefficient of pure liquid water, calculated using the free-water property method
= The fugacity coefficient of water in the vapor phase mixture, calculated using the primary property
method
The K-value of other components are calculated as follows:
where:
is the solubility of component i in water, is calculated using the Hydrocarbon Solubility model (HCSOL). This model calculates solubility of hydrocarbon in a water-rich liquid phase. The model is used automatically when you model a hydrocarbon-water system with the dirty-water option.
The expression for the liquid mole fraction of th
The parameters for about 40 components are stored in the Aspen Physical Property System pure component databank.
Keywords: None
References: C. Tsonopoulos, Fluid Phase Equilibria, 186 (2001), 185-206. |
Problem Statement: What's New in Aspen Plus V7.2 - Overview | Solution: Aspen Plus V7.2 includes over 300 customer-requested enhancements to improve usability and efficiency. Specific examples include:
The new model summary grid now includes tab sheets summarizing process utilities and stream costing.
New sample models for oil shale retorting (Solution129524), and moving-bed and entrained-flow coal gasification processes (Solution 129523).
Improved sample models for carbon capture by activated amines (Solution 129521) and by DEPG and MeOH solvents (Solution 129522).
A new molecular structure drawing tool makes it much easier to estimate pure component properties (Solution 129198).
Distillation column convergence is even more reliable in V7.2.
Many EO synchronization defects have been resolved, enabling equation-oriented simulation for a wider range of processes.
SeeSolution 129195 for more details.
Aspen Plus V72 includes a number of new physical property models including:
New and updated electrolyte models appropriate for all types of electrolyteSolutions including mixed solvent systems and non-aqueous electrolyteSolutions.
The NRTL-SAC activity coefficient model has been updated with an extension to handle electrolytes.
The IAPWS-95 steam table has been added.
The GERG2008 equation of state for natural gas has been added. GERG2008 is a standard (ISO-20765) international reference equation suitable for all natural gas applications, including processing, transportation, and storage of natural gas.
The standard and Dortmund-Modified UNIFAC models have been updated to current standards. The new models include a number of new groups and binary parameters.
The January 2009 release of the DIPPR database has been incorporated into PURE24. This provides updated parameters for many components and adds 29 new components.
Hundreds of additional components have been added to NIST-TRC, and the heat of formation and Gibbs free energy of formation properties DHFORM, DGFORM, DHSFRM, and DGSFRM have been added for many components.
The binary databases in Aspen Plus V7.2 include a number of new sets of binary parameters and many of the existing parameters have been updated with more accurate values.
The molecular structure editor in the User-Defined Component Wizard has been replaced with a greatly improved version which also allows you to save .mol files (Solution 129198).
SeeSolution 129197 for more details.
Several unit operation models have been improved in Aspen Plus V7.2.
The correlations for column flooding have been improved and many additional types of column packing are included in the built-in databases.
The Gibbs reactor model now checks for multiple hydrates.
The Yield reactor model now checks the atomic balance to ensure reactions are valid.
RCSTR, RPlug, and Valve now support the equation-oriented option Remove missing phases and its associated Phase tolerance.
The Pipe model now handles integration failure under choked flow more gracefully, which may allow Design-Specs to find non-choked conditions and converge.
SeeSolution 129200 for more details.
Aspen Plus V7.2 includes many other general enhancements including:
Utility blocks now check for temperature crossover and correct direction of enthalpy flow.
Sensitivity results can be copied to Excel significantly faster than before.
A new Sensitivity Plot Wizard makes it easier to visually display sensitivity results as charts.
There is a new COM-based version of the Excel Calculator add-in for V7.2 which replaces both the XLA version from all past versions and the COM version from V7.1, and fixes several known issues with the previous versions.
Convergence block result forms are more detailed to help you diagnose convergence problems.
SeeSolution 129194 for more details.
The integrated economic evaluation feature has also been improved:
Sizing and cost evaluation calculations are up to three times faster in V7.2
The equipment costing and sizing data persist between sessions
A new operating cost summary form reports the net utility costs for heating and cooling
Enhancements have also been made to other related products such as Aspen Custom Modeler (Solution 129573) and Aspen Batch Process Developer (Solution 129564).
Keywords: None
References: None |
Problem Statement: What is the difference between sizing and rating in tray and packed columns? | Solution: Aspen Plus provides two modes of operation for trays and packings:
Sizing
Rating
Trays
In either mode, you can divide a column into any number of sections. Each section can have a different column diameter, tray type, and tray geometry. You can re-rate or re-design the same section with different tray types and/or packings. Aspen Plus performs the calculations one section at a time.
In sizing mode, the column model determines tray diameter to satisfy the flooding approach you specified for each stage. The largest diameter is selected.
In rating mode, you specify the column section diameter and other tray details. For each stage, the column model calculates tray performance and hydraulic information such as flooding approach, downcomer backup, and pressure drop.
Packing
In either mode, you can divide a column into any number of sections. Each section can have different packings. You can re-rate or re-design the same section with different packings and/or tray types. Aspen Plus performs the calculations one section at a time.
In sizing mode, Aspen Plus determines the column section diameter from:
The approach to the maximum capacity
A design capacity factor you specify
You can impose a maximum pressure drop per unit height (of packing or per section) as an additional constraint. Once Aspen Plus has determined the column section diameter, it re-rates the stages in the section with the calculated diameter.
In rating mode, you specify the column diameter. Aspen Plus calculates the approach to maximum capacity and pressure drop.
Keywords: tray sizing, tray rating, pack sizing, pack rating etc;
References: None |
Problem Statement: What angle should I specify for the vertical pipelines? | Solution: Specify 90 degrees for vertical upward and -90 degrees for vertical downward.
Keywords: Pipeline, Angle, Segment
References: None |
Problem Statement: How are the WATSOL coefficients for water solubility model determined? | Solution: The Water Solubility model calculates solubility of water in a hydrocarbon-rich liquid phase. The model is used automatically when you model a hydrocarbon-water system with the free-water option with a water solubility method (solu-water) of 0, 1, or 2.
The expression for the liquid mole fraction of water (Xw) in each hydrocarbon species is:
ln Xw = C1 + C2/T + C3T for C4 <= T <= C5
The parameters for about 60 paraffins, cycloparaffins, olefins, and aromatics are stored in the Aspen Physical Property System pure component databank. These parameters were determined by fitting literature water solubility data. The average deviations in solubility were 1 ? 5% where most of the date were at temperature of 50°C or less.
In order to handle components for which data were not available, empirical correlations were developed to estimate C1 and C2 in terms of the normal boiling point (TB), specific gravity (SG), and the molecular weight (MW).
Separate correlations were developed for the coefficient C2 and for the solubility at 100°F:
C2 = a Tb^b Sg^c
Xw(100F) = d Tb^e Sg^f
Two sets of coefficients (a, b, c) were determined for different classes of components:
Set
Components
Average Error in C2
1
Paraffins and Cycloparaffins
5.0%
2
Aromatics and Olefins
6.5%
Three sets of coefficients (d, e, f) were determined for different classes of components:
Set
Components
Average Error in Xw(100F)
1
Paraffins
6.0%
2
Cycloparaffins
6.0%
2
Aromatics and Olefins
10.0%
In using the correlations, the component class to which a component belongs is identified in terms of the Watson characterization factor and the molecular weight.
From C2 and Xw (100F), the value of C1 is determined directly:
C1 = ln Xw(100F) - C2/T(100F)
Keywords:
References: None |
Problem Statement: Only parameters referenced by the Property Methods accessed in the simulation are available. Is it possible to access a parameter such as IONMOB that is not used in any Property Method? I want to have the values for the parameter retained, but not have the Property Method there confusing others. | Solution: You can add IONMOB (or any other non-referenced parameter) on the Properties | Advanced | User Parameters form.
You need to know the name of the parameter since there is no drop-down list.
Keywords: None
References: None |
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