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Problem Statement: In addition to the ABML (Aspen Blending Model Library) blending methods available in Aspen Refinery Multi-Blend Optimizer, UBML (User Blend Model Library) provides the ability to incorporate user-defined blending correlations into the model.
How do you set up UBML for Aspen Refinery Multi-Blend Optim... | Solution: The user defined UBML blending methods are stored in a file created by the user called UBML.dll. This file has to be pasted into the Aspen Refinery Multi-Blend Optimizer installation folder, which by default is:
C:\Program Files\AspenTech\Aspen Refinery Multi-Blend Optimizer
In the sample models folder ther... |
Problem Statement: Why is RadFrac offering the option to enter the Reflux Ratio on a Mass, Mole or StdVol base? Shouldn''t a ratio and as such be independent on the basis. And what is StdVol anyway? | Solution: First of all, the StdVol is an option specifically designed for Refinery and Petroleum applications where it is customary to specify the flow as if all components were liquid at 60 F and 15 psi using standard conventional densities defined by the API (American Petroleum Institute). More on that in: http://sup... |
Problem Statement: What do the history file listings mean (Diagnostics MSG-LEVEL=7) for the observed variables in a Data Regression (DRS) run?
For example:
DATA
MEAS
MEASURED
ESTIMATED
ADJUSTMENT
ADJ/STD
1
1
313.15
313.3551
0.2051122
4.102243
1
2
9.799599
9.778381
0.2112181E-01
-5.737799 | Solution: This portion of the history file lists for:
DATA reports the data set specified in the DATA-GROUP paragraph.
MEAS reports the measurement for the specific data set. For example: a TPxy data set will have for each DATA entry four measurements (one for temperature, one for pressure, one for liquid mole fraction... |
Problem Statement: How do I save the optimization report as a text file? | Solution: The optimization report can be saved as a text file by adding USE_HTML to the field ID and setting its value to N in Table CONFIG.
Keywords: MBO Report
Optimization report
Report in html
Report in .txt
References: None |
Problem Statement: How can sulfur and other property data be entered for a petroleum assay? | Solution: Petroleum properties require the user to supply a series of 4 or more property values at the corresponding distillation volume recoveries of the assay. If the user has a bulk value in addition, enter the bulk value to force Aspen Plus to adjust the property versus distillation curve result in a calculated ave... |
Problem Statement: How does Blend Controller Interface (BCI) read property min/max values? | Solution: Here is how PimsBCI reads min/max of properties:
1. Read limit from AB_BLN_QUALITIES
2. Check PropMap to see whether has a ConversionCode, and do a conversion if the user provides it. E.g. SPG_TO_API
3. Check BpcSpecs table to match the same product and same property, if we find it, override limit according... |
Problem Statement: How do I view the different logs in MBO? | Solution: All the reports concerned with a model can be accessed from within and outside MBO:
1. Iteration Log
2. Express Log
3. Model Errors Log
Accessing from within MBO:
The Iteration and Express logs are as shown here: which are hyperlinked in the final report which is showed when running the optimizer:... |
Problem Statement: Why is there a mismatch in the results reported by the Aspen Air Cooler API sheet and Aspen HYSYS outlet streams? | Solution: When using the integrated rigorous Aspen Exchanger Design and Rating (EDR) tools such as Air Cooler or Shell & Tube Exchanger within Aspen HYSYS, the results such as temperatures reported by the EDR tools in API sheet or TEMA sheet may not match with the HYSYS stream conditions.
The reason HYSYS results do ... |
Problem Statement: When importing from MBO and reading the data in BCI, we see the MIN_SPEC and MAX_SPEC equal to the TARGET_SPEC. What could be a possible reason for this? | Solution: Min and max value come from database, from the BCI table (GlobalSpecs, BpcSpecs). You may have set the DeltaMinSpec and DeltaMaxSpec to 0 on BpcSpecs table.
Clear these two cell or change to other number, you may get different min and max
Keywords: Blend Controller Interface, BCI, Min_Spec, Max_Spec, DeltaMin... |
Problem Statement: How do I set the convection banks layout with multiple process streams? | Solution: In Input > Heater Geometry > Convection Banks > Layout option EDR allows the user to set multiple process streams but it is limited to the number of convection banks.
The number of streams that can be added is equal with the number of convection banks, considering that one stream will be attached onto the fir... |
Problem Statement: When comparing some published data from MBO, sometimes we have seen that these values don't match with the values shown in the interface. | Solution: MBO publishes two different sets of data; simulation values (EV tables) and optimization results (AB tables). MBO makes some considerations in order to reduce the size of the problem. If you see that the simulation values and the optimization values are too different you can try by changing the next settings:... |
Problem Statement: RVP using ASTM D323-82 correlation doesn't report any values in my process stream and instead the field is 'empty' | Solution: The RVP or Reid Vapor Pressure, can be reported in Aspen HYSYS by adding it as a correlation on a process stream via the Worksheet tab/Properties page.
The RVP ASTM D323-82 method calculates on the assumption that the hydrocarbon stream is saturated with wet air. Thus, the constituents of air need to be pre... |
Problem Statement: How does Fired Heater calculate Heat Duty in Aspen HYSYS? | Solution: Aspen HYSYS performs energy balance from enthalpies. The efficiency in the heater is the percentage of combustion heat absorbed by the process streams.
Rest of the heat is used to raise the temperature of flue gas from inlet condition to the outlet condition.
Total duty (heat released during combustion) = hea... |
Problem Statement: What is HYSYS OLGALink? | Solution: HYSYS OLGALink is an extension to HYSYS which creates a link to the third-party OLGA2000 software. OLGA2000 is a dynamic multi-phase flow simulation package available from Scandpower Petroleum Technologies.
OLGALink allows source and boundary streams of an OLGA simulation case to be connected to Aspen HYSYS... |
Problem Statement: When I choose either to Estimate Unknown coefficients or Set All to 0.0, my user specified coefficients don't appear to make any difference. | Solution: When using an EOS fluid package in Aspen HYSYS, in the binary coefficients tab the user has two options:
1. Estimate HC-HC/Set Non HC-HC to 0.0; or
2. Set All to 0.0
If the user has binary coefficient data for some or all component interactions, these may be specified as well. However, in order to ens... |
Problem Statement: How to import PVT data from a third-party modeling software? | Solution: ThisSolution contains a video clip which shows you how to import PVT data from the following third-party modeling software:
PVT Pro from DBR/Schlumberger,
Multiflash from Infochem,
PVTSim from Calsep and
GAP Petroleum Experts.
Please note that the video file is over 77MB in size. If you have trouble downloadi... |
Problem Statement: What is PVT Environment? | Solution: The PVT Environment in Aspen HYSYS Upstream is feature access via the Aspen HYSYS Simulation Basis Environment that allows users to import the fluid package, component slate and composition of a reservoir fluid from a third-party PVT modelling software. The PVT environment allows users to import data from
PVT... |
Problem Statement: Heat Duty and Process Stream Duty do not match. How to fix it? | Solution: If you find the difference between the two enthalpies is not acceptable, you can reduce the difference by reducing tolerances. Change one or both of the following.
1. Increase enthalpy relaxation factor up to 1. A factor of 1 means there is no relaxation.
2. Decrease Convergence criterion (temp.) up to 0.05... |
Problem Statement: This is the Blend event from MBO. Note the two text parameters: Description and Comments
This is the text that is required in the XML, coming from the AB_ tables
Now, in the BCI mapping spreadsheet, in the Prodmaps worksheet, there is a description column against each product code.
This is the text t... | Solution: There is a setting, which can be used to control blend description data in XML reports. Follow these steps:
1. Set description on ProdMaps table
2. Select PRODMAP.DESCRIPTION as Misc Blend Description
3. On SpareValue worksheet, use two cells to store value from AB_BLN_EVENTS table, set SpareSt... |
Problem Statement: Does the Fouling Resistance of the tubes impact the pressure drop? How is this reflected in the friction factor of the pressure drop equation? | Solution: Changing fouling factors does not directly change anything included in the pressure drop correlation (e.g. roughness). So no specific equation can be given. However it can impact the pressure drop because of changes to the physical properties of the fluid, particularly if the fluid is vaporizing.
Making large... |
Problem Statement: In the Equation Orientated (EO) strategy, all models use a mole flow and mole fraction (or %) by default to report calculated results. How can I access or create an EO variable for the calculated mass flow or fraction of a stream to be used in a spec-group for example? | Solution: strategy
Keywords: Mass fraction
mass flow
Equation orientated
analyser block
References: None |
Problem Statement: How do I report vapor pressure in Aspen HYSYS? | Solution: There is no direct way to report vapor pressure, however you can add a Property Table for each stream and calculate it.
Go to each stream> Attachments Tab> Utilities> Add> Property Table
Then in the Property Table,
Select the Temperature and the Vapour Fraction as the Independent Variables, and setup the Mode... |
Problem Statement: What are the weight % of sulfolane/MDEA or DEA/water in the components “Sulfinol-M” and “Sulfinol-D? | Solution: The Sulfinol-D model is based on the VLE data from Isaacs (1977).
And the composition of the solvent is 40 wt% DIPA + 40 wt% Sulfolane + 20 wt% H2O.
The Sulfinol-M model is based on the VLE data from Macgregor (1991).
And the composition of the solvent is 20.9 wt% MDEA + 30.5 wt% Sulfolane + 48.6 wt% ... |
Problem Statement: The Hydraulics PFD fails to solve and produces a message ?Invalid Model?. | Solution: This message appears when the internal diameters of the connected pipes are not the same. To resolve this problem place a swage in between the pipes of unequal internal diameters. See details in the attached document.
Keywords: HYSYS Upstream, Aspen Hydraulics, Swage
References: None |
Problem Statement: Is it possible to have actual Reflux Rate as a column specification? | Solution: There is no option for Reflux Rate in the Expert Input page used for the column configuration.
The following steps are guidelines to add Reflux rate as a column specification :
1. Add the column specification type as '' Column Liquid Flow ''
2. Select the condenser stage
3. Select the flow basis
4. Provide ... |
Problem Statement: Best Practices for Aspen Hydraulics subflowsheet in dynamic mode | Solution: Please find below best practices and recommendations for Aspen Hydraulic models in Dynamic mode.
· PVT table generation.
When using Dynamic or Dynamic3P solver, the fluid properties at a given pressure and temperature are obtained by interpolating a PVT table. The PVT table is generated between pre... |
Problem Statement: How do I use an old Fortran subroutine from Aspen Plus 9 in version 11?
There used to be a utility called ap9to10 that would convert Fortran files, but I cannot find it now. | Solution: As per the release notes (What''s New in Aspen Engineering Suite (AES) 11.1, page 4-13 ), AP9TO10 is not supported in 11.1. This is due in part to the componentizaton of Aspen Properties and changes in directory structures that accompanied it.
Customer Support can convert files for customers who do not have a... |
Problem Statement: Unable to install PIPESIM without selecting the subfeatures from Aspen HYSYS Upstream | Solution: Select HYSYS UPSTREAM and selected the sub-features.
Then unselect the sub-features and continue the installation.
Keywords: HYSYS UPSTREAM
PIPESIM
References: None |
Problem Statement: Is it possible to see the values of the calculated heat transfer coefficients on the tube side and shell side? Currently, HeatX displays only the overall heat transfer coefficient. | Solution: They are displayed in the report file only if you select the option Include profiles in report in Options, Report sheet of the HeatX block.
You can display also the heat transfer coefficients on the tube side and shell side separately in the history file. To activate the print-out of these values during the c... |
Problem Statement: If a user has created a simulation using one of the new Refinery templates-
Aromatics- BTX column and Extraction,
Catalytic Reformer
Crude Fractionation
Customized Stream Report
FCC and Coker
Gas Plant
Generic with Customized Stream Report
HF Alkylation
Sour Water Treatment
Sulfur Recovery
there is a... | Solution: To get rid of the error user should delete the reference to the usrpp1b.dat file in Run/ Settings/ Engine files / usrpp1b.dat.
Keywords: Refinery, templates, usrpp1b.dat
References: None |
Problem Statement: Why does the area calculated using PI*D^2/4 for a type D Relief valve differ from the area provided in the NBBI Redbook (NB-18) for Farris Series 2600 Type D valve? | Solution: Looking in the Aspen Plus Pressure\Relief\Safety Valve sheet for the Farris 2600 Type D valve, the diameter for this valve is 0.437 inches, which gives an area of 0.15 inches squared.
NOTE: Although manufacturers list Relief Valves as Type D or H etc... in reality they can all have differing areas due to diff... |
Problem Statement: AspenTech and BR&E released information referring the integration/availability of TSWEET physical property database in Aspen Plus Release 11. What is the status on this interface?
How can this interface be accessed? Is there an additional AspenTech license required or is it available (or will be avai... | Solution: This interface is available in Aspen Plus 11.1, 12.1 and 2004. This interface is not available in Aspen Plus 2004.1 and higher.
The interface includes six additional property methods: 2 for Amines (BRE-NRTL and BRE-KE), 2 for Methanol (MEOH-SRK and MEOH-PR), 2 for Glycols (DEHY-SRK and DEHY-PR).
The TSWEET fe... |
Problem Statement: What are the water solubility (solu-water) calculation methods and how are they used? | Solution: The water solubility (solu-water) method is specified in the Petroleum calculation options section of the Properties | Specifications | Global sheet or of a block's Block Options | Properties sheet.
These methods affect the liquid fugacity of water accordingly:
In the organic phase when using free-water or di... |
Problem Statement: Utilities - Using type :steam or cooling water, what is the property method used? | Solution: Steam and Water utilities use the global free-water property method for the calculation (under Properties \ Specifications under Petroleum calculation options).
Keywords:
References: None |
Problem Statement: Reconciliation in Aspen Plus refers to copying the results of a sequential modular run to the input forms of blocks and streams. Why is this feature in Aspen Plus and when & how should it be used? | Solution: Reconciliation can be very useful when a flowsheet takes a long time to converge. At a point close to theSolution, or better yet after finding aSolution, reconciling streams, which are used as tear streams, and blocks which have their input changed, for instance when using design-specs, will help the next run... |
Problem Statement: Why does my .apw file continually keep growing and growing?
The file size can increase so much that it makes it unable to use run button | Solution: The .apw files do grow with additional information. We allocate large chunks of memory for data If one bit of information remains then that chunk is not cleaned up. After a while the file can become large and fragmented.
We recommend always having a .bkp file and starting from that periodically. In Aspen Plus... |
Problem Statement: I found that I got much better results if I removed a component from the Constraint list for a vapor-liquid equilibrium (TPXY) data-group in data regression run (DRS). Is this recommended? | Solution: It is recommended to remove completely non-volatile components from the Constraints tab on the Experimental data. The constraint is that the vapor fugacity is equal to the liquid fugacity for each component listed on the Constraint tab. If a component is not volatile (such as a polymer, or an ion, that exist ... |
Problem Statement: How does Orion/MBO convert Volume and Weight units when both values are entered? | Solution: If the user enters both WGT (weight) and VOL (volume), the following procedure is used by Orion/MBO to resolve differences, before starting the simulation:
1) if SPG is missing set it to 1.0
2) if VOL is > 0 then recalculate WGT. using the formula for weight below.
3) if VOL is equal to 0 or missing then use ... |
Problem Statement: Why am I not seeing the aqueous phase flow on the hydraulics sub flowsheet? | Solution: Hydraulics in Steady state will not recognize the three phases (vapor, liquid and aqueous phases) as in the Main Simulation Environment. This is because Hydraulics does not work like regular HYSYS. It will solve in terms of pipe unit operations rather than streams (like in HYSYS) so the pressure drop correlat... |
Problem Statement: Sensitivity block is reporting an error when varying the number of stages in a column. | Solution: Using a sensitivity analysis that varies the number of stages on a RadFrac defined with feeds to bottom stage (e.g a Recitfier) you should use a Calculator block to assign the new feed stage and bottoms product stage value for each stream. Skipping this step may cause convergence problems in the column during... |
Problem Statement: What do I need to use Pipesys in Aspen HYSYS? | Solution: Aspen PIPESYS pipe segment is an extension unit operation in Aspen HYSYS. In order to use PIPESYS; you should have a separate PIPESYS license from SPT group and make sure that the extension is registered in your machine.
AspenTech used to provide the PIPESYS license included in the installation of old version... |
Problem Statement: How to change Molar Density (DNLDIP) property parameter values in Aspen Properties database for use in HYSYS ? | Solution: To change any property parameter values, you need to have access to the Aspen Peoperties files (either the bkp or the aprbkp files). The first step is to open any of these files in Aspen Plus (in case you have access to the aprbkp file, you need to import it into Aspen Plus).
When inside Aspen Plus, the prope... |
Problem Statement: How do I specify the sections in which the pipe segment is divided in hydraulics? | Solution: The hydraulics pipe segment allows you to select the number of pipe cells in Design / Data.
The Pipe Cells represent the number sections in which the pipe segment is divided for calculation purposes.
This is equivalent to the Increments in the Hysys pipe segment.
For example, if 5 Pipe Cells are specified, th... |
Problem Statement: How do I find the wall temperature of pipe in Aspen Hydraulics? | Solution: To obtain the wall temperatures the user first needs to configure the detailed heat loss model in the pipe segment.
When the Hydraulic flowsheet is converged the temperature profiles will be shown in the Insulation page under the Performance tab as shown below.
Keywords: Wall Temperature, Pipe in Hydraulics
R... |
Problem Statement: Does the PIPESYS extension work with black oil streams? | Solution: As shown in the figure below, the PIPESYS extension is compatible with black oil streams. Please refer to the attached simulation file for an example.
Keywords: black oil, PIPESYS, extension
References: None |
Problem Statement: Why are so many property parameters missing for Helium? | Solution: The most common isotope of Helium is Helium-4.
There is a component named Helium-4 in Pure10 and Pure11 that has a fairly complete set of property parameters. Helium-3 is a minor isotope that is also available in the Purexx databanks.
Starting in Aspen Plus 11.1, a component named simply Helium with a formula... |
Problem Statement: How you can choose part of the flowsheet (a hierarchy for example) to be solved in sequential-modular (SM) while the rest is solved in Equation-Oriented (EO) mode? | Solution: The mixed mode strategy enables you to solve individual
hierarchies in SM or EO. The overall strategy is then considered
SM. This feature is only available in simulation mode.
This mode is useful to
Migrate flowsheets one section at a time from SM to EO.
Converge flowsheets where one section has many tear st... |
Problem Statement: Moving the ''Program files'' folder (or its contents) back and forth damages the shortcuts to the Aspen Plus Simulation Engine.
Explanation
Once Aspen Plus 10.2 is installed on Windows, shortcuts to the different .bat and .exe files are created.
The shortcut to the executable program that opens the ... | Solution: Correct the shortcut to the Simulation Engine in the Start menu. (Start Menu - Programs - AspenTech - Aspen Engineering Suite - Aspen Plus 10.2 - Aspen Plus Simulation Engine)
Edit the AspSetup.bat file located in ..\Program Files\AspenTech\Aspen Plus 10.2) and correct the path assigned to the asptop environ... |
Problem Statement: How do you add components to the FACT databank? | Solution: Below are the instructions about how to
add components to the Aspen Plus engine and the Aspen Plus User Interface. This is a general process that is applied to the FACT databank.
Overall, there are two steps,
Use DFMS to add the new components to the FACTPCD.
Customize the GUser Iinterface.
Keywords: chemapp
... |
Problem Statement: Which parameters should I regress when using isothermal VLE or LLE data to regress binary interaction parameters for an activity coefficient model? | Solution: The excess Gibbs free energy has the general form:
E n E E
g = RT Sum ( x ln gamma ) = h - Ts
i i i
AspenTech's activity coefficient model temperature dependencies are of the form (Aspen Plus 8.5-6 and earlier have a and b, Aspen Plus
9... |
Problem Statement: When VBA code tries to hide a Design-Spec that is already hidden in an Aspen Plus model, an error is returned. Is there some way to check if the Design-Spec is already hidden before accidentally trying to hide it again? | Solution: There are a few different ways that this can be done.
Option 1
Probably the easiest way to detect when a particular Design-Spec is already hidden, is to use the On-Error checking and then try to hide the Design-Spec. If it is already hidden, you will get an error message.
Example code:
Private Sub cmd_HideDe... |
Problem Statement: I have heat of vaporization data for a substance, and I''m trying to fit the first two elements of parameter DHVLDP. I know that element 1 is roughly 1E7, and element 2 is roughly 0.1. However, if I enter these values for the scale factors on the Properties--> Regression form, my regression run appea... | Solution: The problem is due to confusion about Aspen Plus''s definition of the term scale factor. In the Aspen Plus data regression system, scale factor is actually used as a multiplier. The scaled quantity is computed as the quantity multiplied by the scale factor.
To help the regression, the aim should be to have th... |
Problem Statement: How will ICARUS be integrated into the Aspen Engineering Suite (AES)? | Solution: Aspen Tech acquired ICARUS corporation to enhance our customers'' engineering decision making. With the ICARUS product family, AspenTech now has the ability to enhance engineering knowledge with economic knowledge, providing a truly powerful offering.
The ICARUS product family is now part of the Aspen Enginee... |
Problem Statement: How can I use kinetic and equilibrium reactions together in a RadFrac column? Can this be done by having the equilibrium reactions defined globally in Data\Reactions\Chemistry and the kinetic reactions defined as type REAC-DIST in the Data\Blocks\RadFrac\Reactions sheet? | Solution: For RadFrac columns, if you have a reactive system, you have to use either CHEMISTRY and / or the REAC-DIST type in the REACTIONS paragraph (Data\Blocks\Column\Reactions sheet).
REAC-DIST allows Kinetic, Equilibrium and Conversion reactions to be supplied, all in the same reaction set (e.g R-1) if required. F... |
Problem Statement: There are 3 Absorber icons (ABSBR1, ABSBR2 and ABSBR3) for RadFrac that appear to be the same. What is the difference? | Solution: At one time, the 3 icons were different in the appearance on the Process Flow Diagram (PFD) or workspace. The icons had different feed locations for inlet streams. Now, all of the feeds are in the same location. Since the Icon information is saved in .bkp files, old bkp files upward compatibility will be an i... |
Problem Statement: Which properties are required from a CAPE OPEN ThermoPackage when it is called from Aspen Plus? | Solution: The following properties may be required by Aspen Plus:
'fugacityCoefficient'
'fugacityCoefficient.Dtemperature'
'enthalpy'
'heatCapacity'
'entropy'
'entropy.Dtemperature'
'gibbsFreeEnergy'
'gibbsFreeEnergy.Dtemperature'
'volume'
'volume.Dtemperature'
Note that 'heatCapacity' is required instead of 'enthalpy.... |
Problem Statement: Unable to load the Excel Add-In to run the Calculator Block | Solution: If user is going to uninstall a previous version of Aspen Plus, it must be done BEFORE installing the new version otherwise there will be problems with the Excel Add-In.
If you do need to uninstall a previous version of Aspen Plus AFTER installing an newer version, you may need to re-install the newer version... |
Problem Statement: What is the source of costing estimating data in Aspen Plus input language? | Solution: All cost estimating featues of Aspen Plus have been superseded by ICARUS system, and are no longer support in the User Interface (GUI).
Aspen Plus equipment cost estimates are based on methods defined by PDQ$ Inc. The PDQ$ routines are integrated into the Aspen Plus Costing system to estimate the cost of both... |
Problem Statement: What changes were made to the HEATX model's calculations between versions 10.2 and 11.1? | Solution: 1. Actual exchanger area will be provided in all output. In version 10.2, actual area was not shown in results when area was specified as input for shortcut method.
2. Actual area will always reflect the specified input area. If the detailed method is used and no area is specified, the area calcul... |
Problem Statement: For a water stream at 60 F and 1 atm which enters a flash block at 60 F and 1 atm, the water coming out of the block should also be at 60 F and 1 atm. The standard volume (STDVOL) for the inlet stream is 22.4 l/min, but the volume flow for the outlet stream is 22.29 l/min, why are they different?
Is ... | Solution: When standard volume is specified for the feed flow rate, the standard liquid volume flow is converted to mass flow rate using the standard liquid volume. Standard liquid volume (defined at 60F, 1 atm) is calculated from the parameter VLSTD (Standard liquid molar volume of a pure component at 60 F) which is s... |
Problem Statement: Can I use a different databank for the same component in different parts of the Aspen Plus flowsheet? | Solution: This is not possible directly.
However, a workaround is to create two component names for the same component, and for the second component enter manually the pure component and VLE data in the Properties / Parameters / Pure Component and Binary Interaction forms. You could then use an RStoic block between dif... |
Problem Statement: This is an application to strip acetoaldehyde from water. After calculation converged, the following error was given during report generation although result status indicated Result available:
*** Severe Error
Single Phase tenmperature calculations failed in 15 iterations. Final temperature is 145.08... | Solution: It doesn't seem serious error. But we should not ignore this message. This error message should not be ignored since it is due to a flash failure in one of the streams that is probably indicative of physical property problems. Looking at further the problem, it was found that too low gas feed temperature caus... |
Problem Statement: How can one simulate a column without a condenser and reboiler (e.g. an absorber) in Aspen Plus? | Solution: Use the RadFrac model and specify None for the condenser and the reboiler. No other columnn specifications are needed since no condenser sets the top stage duty to zero and no reboiler sets the bottom stage duty to zero. Do not try to specify zero reflux or zero boilup.
As RadFrac requires both vapor and liqu... |
Problem Statement: There was an error message in the control panel about PHIMX. How does one find the definition? Search retrieved nothing.
Cause
The problem is that PHIMX is in Aspen Physical Property System help. | Solution: Click on Aspen Physical Property System Help in the right hand pane and then search.
Detailed Explanation
When the property system help became shared between the Aspen Plus and Aspen Properties products, it was found to be impossible to integrate the contents properly. In particular, if the help contents fil... |
Problem Statement: In some simulations which involve electrolytes, the following warnings are printed to the Aspen Plus Control Panel:
WARNING IN PHYSICAL PROPERTY SYSTEM ATTEMPT TO USE MODEL ELECNRTL WITHOUT A SOLVENT. ACTIVITY COEFFICIENT OF UNITY IS USED
WARNING IN PHYSICAL PROPERTY SYSTEM WHILE PERFORMING INITIAL ... | Solution: ELECNRTL is applicable to systems containing electrolytes. i.e., aqueous systems. Water is required to define the standard state of the ions and possibly also the standard state of the molecular solutes (e.g., Henry components). Whenever you try to apply the model to a system which is free of water, the above... |
Problem Statement: How is it possible to model a Plug Flow Reactor with RPLUG and adjust for less than perfect radial mixing? | Solution: This is similar to adjusting the efficiency of the RPLUG model. To adjust the efficiency of the reactions in an RPLUG block simply add a bypass around RPLUG. With this model a Design Spec or Sensitivity Analysis can now be added to match plant data.
See attached example.
Keywords: reaction
efficiency
Referenc... |
Problem Statement: Unable to start License Manager. If running under Windows NT, there will be an NT Event log entry. If running under Windows 9x, there will be no error messages. | Solution: The cause could be that the clock inside the SuperPro dongle and the PC clock differ by more than 4 hours. This occurs most commonly when the customer has performed Year 2000 testing and attempts to run the License Manager after resetting the PC clock.
Log file entry
00-Jan-07 14:31:23: Loaded key C:\PROGRA~1... |
Problem Statement: Can the Cavitation Index for a valve be calculated in Aspen Plus? | Solution: The likelihood of cavitation is measured by the cavitation index. The cavitation index can be calculated in the VALVE model to predict cavitation in a chamber or other system.
Cavitation index for the specified inlet stream conditions is calculated if the Calculate Cavitation Index box on the Valve \ Input \ ... |
Problem Statement: When using the Wilson-LR (or Wilson-GLR with Liquid as reference state) the vapor phase Cp is exactly equal to the values reported by other property methods such as Ideal or NRTL. Why is that since the calculation route must be different (at least they do not have the same reference state)? | Solution: Attached are details about vapor-phase Cp calculation for the Wilson-LR property methods, compared to the Ideal or NRTL property methods.
For mixture vapor-phase enthalpy (HVMX) calculations, results differ for the vapor phase enthalpy with the Wilson-LR property methods which is using the saturated liquid as... |
Problem Statement: How can parallel, series and mixed reactions be modeled using RStoic? | Solution: In PARALLEL (or COMPETING), reactions, one reactant forms multiple products through separate reactions, e.g.:
A ---> B
A ---> C
In SERIES (or CONSECUTIVE) reactions, a reactant is consumed to form an intermediate product, which then reacts again to form the final product, e.g.,
A ---> B... |
Problem Statement: How can I check the valid temperature, pressure and composition range of built-in binary parameters? | Solution: To verify the ranges of built-in binary parameters for activity coefficient models complete the following steps:
1. Go to the Properties \ Parameters \ Binary Interaction forms in the Data Browser. The object manager for all binary parameters appears.
2. Double click on the name of the parameters that... |
Problem Statement: How to include IF…THEN statement in a Fortran Calculator block so Aspen Plus can interpret it. | Solution: The example attached illustrates the use of IF…THEN statement in a Fortran Calculator block so Aspen Plus can interpret it.
Taking into account the configuration above, the aim of the Calculator block is to adjust the amount of water coming into the Heater (COOLW mass-flow), so the outlet stream temperature... |
Problem Statement: RadFrac has a simple thermosyphon reboiler. How do you simulate a rigorous thermosyphon model coupled to RadFrac? | Solution: To obtain thermosyphon reboiler process feed stream data from RadFrac:
1. Start by connecting a new stream to the pseudo stream connection port on the RadFrac block in the flowsheet view. The pseudo stream connection port is typically located on the right side, towards the center of the RadFrac icon.
2.... |
Problem Statement: The diagram Variable Explorer.bmp shows the Variable Explorer tree for the RYIELD reactor block B1 in the RYIELD.bkp simulation. In the RYEILD reactor model, the specified yield for each component are held in the input variable MOLE_YIELD:
Application.Tree.Data.Blocks.CHARSPLT.Input.MOLE_YIELD.(CHAR,... | Solution: Below is the VB code to access an Aspen Variable that has a paired identifier. In this example, we access the specified yield in RYIELD block B1 for non-conventional component CHAR:
Dim go_simulation As IHapp
Dim ihCHAR As IHNode
Dim Yield As Double
Set go_simulation = GetObje... |
Problem Statement: What is a Production Allocation Utility and how do I use it? Is there a known issue with the Utility? | Solution: The Production Allocation Utility enables you to track the contribution of selected streams to other down flowsheet streams. The contribution is tracked on a compositional flow or percentage basis. Use of the Production Allocation Utility is particularly relevant in scenarios where a model depicts a system th... |
Problem Statement: How to I set up an enthalpy / pressure diagram for a HF / H2O system? | Solution: First, create a simulation with H2O / HF as components and use the electrolyte wizard to generate the electrolytic components and chemistry. The enthalpy / pressure diagram can be easily created using a Generic type of Analysis available from the Properties Analysis forms. The run mode can optionally be chang... |
Problem Statement: How do I reference a RadFrac internal design specification target value for use in a Sensitivity block, or a Calculator block? | Solution: When you define the variable accessing the design specification target, choose the
Keywords:
References: Type Block-Var followed by the block name, followed by the Variable VALUE.
VALUE here is defined in the text at the bottom of the window as Desired Value of Design Specification specified variable, in SI ... |
Problem Statement: How can I find if binary parameters are provided in Aspen Plus or Aspen Properties binary databank for a specific component with any other component available in databanks for activity coefficient models such as NRTL or UNIQUAC? This is useful since binary interaction parameters are critical for corr... | Solution: In AES 11.1 and higher, there is a file called binary parameters for gamma models.xls in the APrSystem xxxx\GUI\xeq directory. In this file, you can search the list of component pairs available in the VLE-IG, VLE-RK and VLE-HOC databanks. Details about what is included in this file is given below. The Aspen P... |
Problem Statement: I'm using a Chemistry set and a Reaction set in a RadFrac column or kinetic reactor. They are set up as equilibrium reactions and have the same specifications and same basis, but they are giving different results. Why is that happening? | Solution: Chemistry always uses Activity for calculations, so is only differentiated between using mole fraction or molality when calculating activity (multiplying basis by gamma). Thus, basis for Chemistry was called Molality or Mole fraction.
For Reactions, additional bases were added for it, such as Mole fraction (i... |
Problem Statement: When the user clicks on a stream in the flowsheet view and then rigfht clicks, there is no longer an ANALYSIS option. This feature used to generate property analysis for just the currently highlighted stream. | Solution: In version 10.1 and in earlier versions of Aspen Plus, this feature was attached to the stream object. In version 10.2 and later, this feature is only accessible from the Tools menu.
First, highlight the stream by clicking the left mouse button on it in the flowsheet view. From the TOOLS menu select Analysis.... |
Problem Statement: Customer is unable to access the License Manager, either through a Point | Solution: or using the asplmadm command.
Solution
The network does not have proper TCP name reSolution in place. The customer can use one of the following techniques to establish TCP name reSolution
DNS Server
WINS Server, for Windows Only environments
LMHOSTS File, for Windows Only Environments
Local HOSTS file
Test t... |
Problem Statement: How is the Equation Orientated (EO) Input form used? Are these values used in the Sequential Modular (SM) simulation? | Solution: The Equation Orientated (EO) Input form is used to assign values to constant variables. For example, if a Spec Group is used to change the specification of variables, then the newly assigned Constant variable is given a value using the EO input form.
If the simulation is run again in Sequential Modular (SM) m... |
Problem Statement: How is the rate of reaction interpreted? | Solution: The rate of reaction is not associated with a single species. The rate calculated from the pre-exponential factor (k0), activation energy (Ea), composition dependence, etcetera, is multiplied by the stoichiometric coefficient for any species, so that:
Rate of Reaction = r
For example, in the reaction:
2A +... |
Problem Statement: What is the definition of the shell side maximum cross flow velocity as reported in the HeatX heat exchanger? | Solution: The shell side maximum cross flow velocity is as follows.
HeatX:
Shellside maximum crossflow velocity = total shellside stream mass flow / crosssection area / two-phase homogenous density
For segmental baffle cut, the cross sectional area is the cross section area near the shell centerline.
For rod baffle cut... |
Problem Statement: Where can I find critically evaluated physical property data sources and non-evaluated sources? | Solution: Some sources of phyisical property data are listed below.
Pure Component Property Sources
Critically Evaluated Data Sources
Editors have reviewed all sources and selected the data reported after testing and comparative analyses. (See below for electronic availability of data)
Chase, M. et al., in JANAF Therm... |
Problem Statement: How does one model the pressure drop calculations involving piping joining at a T? | Solution: A MIXER block is needed to model a T. The outlet pressure is specified (not calculated) in the MIXER.
In order to determine the pressure drop, it is possible to use a Calculator block. The Calculator block can be used to solve for the final system pressure using the Bernoulli Equation and then write that valu... |
Problem Statement: In Aspen Plus, is the Prop-Set for PH25 the same as the Prop-Set for PH with TEMP=25? | Solution: The Property Sets PH25 and PH with the Temperature specified as 25 are not the same.
PH25 is calculated by reflashing the stream at 25 C. By reflashing the stream, both the liquid composition and the activity coefficients will be changed.
PH TEMP=25 C does not reflash the stream. The compositions calculated a... |
Problem Statement: When a RadFrac column model includes specifications on Murphree stage efficiencies, the K-values (= yi/xi) reported on the RadFrac Profiles K-Values Sheet do not agree with the vapor and liqiud composition profiles reported on the RadFrac Profiles Compositions Sheet. Why do the KVL-values and molar c... | Solution: The issue is that you are calling yi/xi the K-value, but this is true only at equilibrium. If we define
eta = efficiency
y = vapor composition exiting tray
x = liquid composition exiting tray
y* = vapor composition enterring tray
K = thermodynamic K-value
then
y - y*
eta =
--------
Kx - y*
or
(y- y*)... |
Problem Statement: When I select HeatX, there are many icons. Right click mouse, for example, select E-HS-1CN. What do the letters stand for? | Solution: The icons that can be used to represent a HeatX block look different but the model is the same for all of them. They, all, feature the same number/type of connections/ports. It is important to connect the right streams to the right ports (i.e. the hot stream to the hot port and the cold stream to the cold por... |
Problem Statement: How to use the vent algorithm for RBatch to improve convergence. | Solution: To use the improved Vent algorithm in RBatch, specify the reactor volume and the vent opening pressure to calculate the reactor pressure rather than specifying reactor pressure. This process may help an RBatch process converge.
In Aspen Plus 10:
Specify Calculate reactor pressure on the RBatch / Setup / Speci... |
Problem Statement: An In-house databank or User databank has been generated for Aspen Properties and the Graphical User Interface (GUI) has also been customized to access this databank. When upgrading, what is the procedure to use these customizations? | Solution: You must rerun DFMS with the latest version to create the databank. You must also rerun the Graphical User Interface Customization (MMTBS) to include the databank in the GUI. SeeSolution 4337 for step-by-step instructions of how to create user or inhouse databanks.
WARNING When customising, you MUST save all ... |
Problem Statement: I know the characteristics of a petroleum blend and a product that will be removed from the blend. Is there an easy way to calculated the properties of remaining blend with the product removed? | Solution: Once the pseudo component compositions for the blend and products are known, one can essentially do this calculation in Excel (or by hand if you wanted to). Attached is an example using an Excel USER2 block to do the calculation.
The example contains two files, an Aspen Plus .bkp file and an Excel file. In th... |
Problem Statement: How are the different streams in an RBatch calculated? | Solution: RBatch can operate in a batch or in semi-batch mode. The reactor mode is determined by the streams you enter on the flowsheet. A semi-batch reactor can have a vent product stream, one or more continuous feed streams, or both. The vent product stream exits a vent accumulator. It does not exit the reactor itsel... |
Problem Statement: Occasionally, the stream data tags (which display temperature, pressure, mass flowrate or duty/power on flowsheet) do not show up on the flowsheet, even though user has selected the proper items under Tools -> Options -> Result View tab and also selected Global Data under View. | Solution: This seems to be a small glitch in the program, where occasionally the Global selections do not become activated and must be refreshed manually. TheSolution is to:
Go to Tools / Options and click on the Results View tab.
In the Stream results box, deselect all options.
Click on Apply.
Now reselect all the des... |
Problem Statement: What are the Electrolyte Inserts? How are they used? | Solution: An insert is a partial backup file that you can import into a run at any time. You can use an insert to create a:
Property package, consisting of component and property definitions
Standard process unit, such as a crude column and its preheat train
You can create your own inserts, or you can import inserts f... |
Problem Statement: Where do I find the gas treatment solvents, Selexol and Purisol, in the Aspen Plus pure component databanks? | Solution: These properties are found as described below:
Selexol
The physical properties of DOW's Selexol or Coastal Chemicals' AGR are not public information. This component is also known as Dimethyl-Ether-Polyethylene- Glycol (DEPG).
Previously, the company that licensed Selexol would work with their customers to pro... |
Problem Statement: What is an adiabatic Pipe? Although a PIPE model is specified to work adiabatically (zero duty), the calculated heat duty which reported among the thermal results is non-zero. What is the reason? | Solution: The difference in enthalpy is due to the change in elevation. One of the terms in the Bernoulli equation is the potential energy term, which takes into account the change in elevation. Due to the additional pressure drop caused by the elevation, the outlet stream has a different pressure and temperature. Thes... |
Problem Statement: Why is the AMINES propery method warning displayed for a system where the limits are not exceeded ?
The file runs and gives several warnings of the type:
WARNING IN PHYSICAL PROPERTY SYSTEM WHILE GENERATING REPORT FOR STREAM: OUTLET THE AMINE CONCENTRATION OF 59.8 WEIGHT PERCENT IS OUTSIDE THE VALID ... | Solution: At first sight, this may seem unreasonable, since the concentration of the amine is 15 % b.w., which is well in the admittable range.
The message leaves the user with the impression that Chao-Seader is used for all the calculations. This is not the case. Chao-Seader is only used for the calculation where the ... |
Problem Statement: There are problems installing Aspen Plus 2004.1 Cumulative Patch 4. It will return errors when someone tries to apply it. If Aspen Plus 2004.1 is installed and there is no cumulative patch applied, then CP4 will install with no problems.
If CP1 or CP2 are installed, then CP4 will not install and it... | Solution: First, after a failed installation of Cumulative Patch 4, start Aspen Plus. The messages about installing are normal as Aspen Plus needs to repair itself. Let this process run its course. Open a test file and verify that Aspen Plus is still working. Then exit.
Next, download and re-apply Aspen Plus 2004.1 C... |
Problem Statement: What is the meaning of the number (-1) for element 5 of UFGRP in the parameter report for trichloroethylene (see Properties Parameters Results Pure Components T-Dependent Sheet)? | Solution: If you take a look at the Physical Property Data
Keywords: UNIFAC
UNIF-LL
UFGRP
Parameter Report
Special UNIFAC Liquid-Liquid Functional Groups
Group Contribution Methods
References: Manual, Chapter 3, Table 3.13, you will notice that trichlorethylene belongs to a group of components for which special UNIFAC ... |
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