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Problem Statement: It can be difficult to compare two different values for a specific point in time because even though two different tags may have history that matches down to the hour, minute and even second, the timestamps will rarely match to the 10th or hundredth of a second. | Solution: Here is an example script where the goal is to collect data from record a where the value is greater than 100 while at the same time the value of record b is between 1 and 2:
SELECT a.IP_Trend_Time,a.IP_Trend_Value FILLER PERCENT,
b.IP_Trend_Time,b.IP_Trend_Value Product
FROM mytag1 a,mytag2 b
WHERE b.IP_Trend_Value Between 1 and 2
AND a.IP_Trend_Time=b.IP_Trend_Time
AND a.Ip_Trend_Time between ''01-SEP-00 6:00'' and ''24-SEP-00 06:00'' AND a.IP_Trend_Value>100;
Notice the line:
AND a.IP_Trend_Time=b.IP_Trend_Time
Because of the reSolution of the timestamp, the times will rarely be exactly the same and an inaccurate (or at least incomplete) dataset will result.
TheSolution is to use the CAST command to make the timestamps into strings that represent the timestamp to a lesser reSolution. Note that it is not enough to simply CAST the timestamp as a TS15, TS18 or TS20 -- those CAST options are affecting appearance only. It is necessary to convert your timestamp to a string, which can then be compared for equality to another string. So, by changing the above line to:
AND (CAST(a.IP_Trend_Time as CHAR FORMAT ''DD-MON-YY HH:MM:SS'')) = (CAST (b.IP_Trend_Time as CHAR FORMAT ''DD-MON-YY HH:MM:SS''))
the result set will include every occurence of a.IP_Trend_Time=b.IP_Trend_Time where they match to the second.
Look at the SQLplus Help files to see a complete listing of the CAST command and all of its timestamp-related formatting arguments.
Keywords:
References: None |
Problem Statement: Is it possible to open a Visual Flare or a UniSim file in Aspen Flare System Analyzer? | Solution: A Visual Flare (.vmf) file is part of Schneider Electric Software and a UniSim Flare (.ufnw) file is part of Honeywell and those types of files are not part of the Aspentech suite.
Nowadays it is not possible run a Visual Flare or UniSim file within Aspen Flare System Analyzer, since both have changed their codes and Aspen Flare System Analyzer has had some improvements in recent times.
Keywords: Visual Flare, UniSim, .ufnw, .vmf, Aspen Flare System Analyzer, Convert, Open
References: None |
Problem Statement: What does the petroleum property correlation ‘P Value’ measure? | Solution: Starting with V9.0, Aspen HYSYS reports ‘P Value’. This property correlation is a measure of the residuum stability and is often used for the visbreaker tars in a refinery. ASTM D6703 is used to measure the ‘P Value’.
This correlation is based on the test method, intended for estimating the colloidal stability of bitumen asphalt, asphalt cross blends, aged asphalt, and heavy oil residuum.
This property correlation may be used either at stream or flowsheet level.
To add this property correlation onto the Properties form of a specific material stream, double-click on the material stream and go to the Properties form. Then, click on the 'Append correlation' button and look for this property under the Petroleum correlations group.
Also, this property correlation can be added to all material streams at once. To do so, click on the 'Correlation Manager' under the Simulation section of the home tab of the ribbon (see image below). Then, look for this property under the Petroleum section and activate it.
Keywords: P Value, Residuum, Stability, Refining, Visbreaker Tars.
References: None |
Problem Statement: How can you model a delay orifice opening in BLOWDOWN? | Solution: To simulate a delay in the orifice opening in BLOWDOWN, you need to enter a small number for the orifice opening (for example 0.01).
The value can be increased later at the desired time interval.
Please note that this is only possible in Aspen HYSYS V10.
Keywords: Orifice, BLOWDOWN, delay
References: None |
Problem Statement: Can hypocomponents be merged into one in Aspen HYSYS? | Solution: There is no functionality in Aspen HYSYS to combine two pseudo components into one as you can do in Aspen Flare System Analyzer.
In Aspen HYSYS, each pseudo component has its own physical properties.
As a workaround, you can mix two streams with the hypos to obtain the mixture properties.
Keywords: Hypocomponents, combine
References: None |
Problem Statement: What does the Recycle Advisor do in Aspen HYSYS? | Solution: In a HYSYS flowsheet the number of recycles and their locations significantly affect case convergence. In iterative solving, more recycles will make the case converge slowly, and will result in additional degrees of freedom which in turn will affect the robustness of theSolution. For these reasons, having just the required number of recycles and at the right locations is important. The Recycle Advisor is a flowsheet analysis tool that helps the user to determine the appropriate number of recycles and their locations.
It can be accessed via the Flowsheet/Modify Ribbon Tab.
The Recycle Advisor analyses the stream connectivity of the flowsheet, and then identifies loops and determines ideal positions to break the loops with minimal cuts. These will be the desired recycle positions. The Recycle Advisor then compares the ideal positions to those of the current recycles and recommended actions - to keep or remove existing recycles, and add new ones if needed. You can still choose to follow only some, all, or none of the recommended actions depending on the flowsheet and the extent of changes you want to make.
Keywords: Recycle Advisor, Flowsheet,
References: None |
Problem Statement: What steps should be considered if there are difficulties in converging a distillation column or obtaining the required performance from the column. | Solution: If the column is not converging the diagnostic output generated in the trace window during the column iterations provides helpful clues on how the solver is progressing. If the equilibrium errors are approaching zero, but the heat and spec errors are staying relatively large, the specifications are likely difficult to meet. If both the equilibrium errors and the heat and spec errors do not converge, then the column inputs for example, the initial estimates, the specifications, and the column configuration should be examined.
Before starting the troubleshooting steps listed below, first reset the column and then run it again. The Reset button will purge all estimates from the previousSolution.
Column Configuration
Check the following list for column configuration:
Feed Stage Location: If the feed stage is too high or low from the optimal then the column might be pinched. Pinching can be best detected by using a x-y diagram by using the McCabe Thiele extension for Aspen HYSYS, available fromSolution 110069.
Feed Temperature: Too hot or too cold feed temperature might affect some trays and cause either pinching or a portion of the column to run dry.
Reflux ratio: Usually distillation columns operate close to the minimum relfux. However numerically this can be difficult to converge at minimum reflux condition.You may first start with a higher reflux ratio and if the column solves with this then lower this progressively to the actual value.
Impossible specifications: Some specifications might not be feasible. If the simulation has problems meeting an active specification, check the Design | Monitor or Spec page of the column:
Extreme purity: The purity specification might not be feasible with the current setup of the column.
Specification of more than one purity or recovery for the same component may not be possible to meet.
Avoid specifying all the products from the column.
If any product rate is specified check that this can be achieved with the given feed rate.
There is no vapor or liquid phase exist at the specified temperature.
Bad Estimates: Estimates can help converging the column. A bad estimate might take longer to solve or may not converge at all.
Two liquid phases: If there is two liquid phases you might need to add water draws for the water to exit or use Sparse Continuation solver (refer toSolution 109406) .
Once a column is solved the results can be viewed from the Performance tab within the column flowsheet. In the Performance tab | Plots Page of the column, you can display temperature, flow composition and Key ratio plots or tables (LK/HK - Light Key / Heavy Key components).
Initial Estimates
If the column specifications and feeds are setup correctly the problem might be due to poor initial estimates. Difficult separations require temperature and or flow estimates. Temperature and flow estimates can be entered in the Parameters tab | Profiles page of the column. Composition estimates are available from the Parameters tab | Estimates Page. Estimates can also be entered as non active specifications, by ticking the estimate radio button. However make sure the estimates are reasonable otherwise the column might not converge at all.
To generate estimates you can activate the Dynamic Integrator for IEG option from Parameters settings. This will generate estimates by running the column in dynamics (relaxation method).
Solver
If the solver oscillates it might be useful to decrease the dumping factor or to enable the adaptive damping from the Parameters tab | Solver page.
Solver methods:
HYSIM Inside-Out
General purpose method, which is good for most problems.
Modified HYSIM Inside-Out
General purpose method, which allows mixer, tee, and heat exchangers inside the column subflowsheet. Only a simple Heat Exchanger Model (Calculated from Column) is available in the Column subflowsheet. The Simple Rating, End-Point, and Weighted models are not available.
Newton Raphson Inside-Out
General purpose method, which allows liquid-phase kinetic reactions inside the Column subflowsheet.
Sparse Continuation Solver
An equation based solver. It supports two liquid phases on the trays, and its main use is for solving highly nonideal chemical systems and reactive distillation.
Simultaneous Correction
Simultaneous method using dogleg methods. Good for chemical systems. This method also supports reactive distillation.
For more details on the various solver methods and further troubleshooting advice consult the Aspen HYSYS F1 Help Menu.
Keywords: Column Convergence, Solver method
References: None |
Problem Statement: Continuous List datasheets cannot be opened from Workbench (Legacy Datasheet editor). The error bellow appears
How can I view / use the continuous lists? | Solution: By design, Continuous List datasheets cannot be opened in Workbench (Legacy datasheet editor). The continuous list format is new, developed for Excel Datasheet Editor application and not retrofitted to Workbench. This is one of the advantages of using XLDSE.
These lists can be opened in ABE Explorer application if Tools | Preferences is set to Excel.
Keywords: Datasheet Type, AZ Continuous List, AZ Error
References: None |
Problem Statement: What is difference between Liquid Volume Percent and Liquid Percent Level in the Vessel? | Solution: Please find below the calculation details of these variables:
Note: For horizontal vessel, Liquid Volume Percent will be different than Liquid Percent Level if the Liquid Percent Level is not 50%. Refer to the following screenshot and attached Aspen HYSYS Dynamics file. The spreadsheet shows the Liquid Volume Percet Calculation.
Keywords: Liquid Percent Level, Liquid Volume Percent, Vessel, Specs, Dynamics, Model Details, Volume.
References: None |
Problem Statement: How does the program decide when is it necessary to perform the flash calculation for RPlug reactor in Aspen Plus? | Solution: The flash calculation is necessary except in simple cases where there is only single phase present and apparent approach is used (no electrolyte with chemistry is considered). If the scenario is more complicated, for example, if heat exchange is considered, flash may also be necessary even if single phase and apparent approach.
Keywords: RPlug, Convergence, Flash Calculation
References: None |
Problem Statement: Which components have Vapor Phase Dimerization or Association included in HYSYS? | Solution: The carboxylic acid vapor phase dimerization/association is accounted for, for the following components, if an Activity Coefficient Model is used for the liquid phase, AND the virial equation is selected as the vapor phase model. Please note that this applies to the listed components ONLY.
The components are:
ID # Name
700 Formic Acid
701 Trifluoroacetic Acid
702 Acetic Acid
704 Propionic Acid (not included in DISTIL, but is in Hysys)
706 Butyric Acid
707 IsoButyric Acid
708 Valeric Acid
711 Hexanoic Acid
713 Acrylic Acid
708 m-Acrylic Acid
3391 n-Nonanoic Acid
3425 n-Decanoic Acid
Keywords: virial, vapor phase association, dimerization, carboxylic acids
References: None |
Problem Statement: APC application will give an error All licensing tokens with the server for this feature are already in use even though there are enough overall tokens available in the SLM server | Solution: Each APC application can only take all the token required in one bucket. For example, if the application requires 20 tokens and the SLM server is configured such that bucket 2 has 15 tokens left and bucket 3 has 20 token left, the application would not run. If you look at the license log, you would see errors 0xC8001006. All licensing tokens with the server for this feature are already in use for each of the bucket configured.
The software is designed to take all the tokens required to run that application in one bucket. So if the first bucket doesn't contain all the tokens, it will skip and go to the next bucket with the same request (for all the required tokens). It is not designed to partially take all the tokens from the first bucket and get the remaining token from the next bucket.
Before running an APC application, make sure that there are enough required tokens in any one configured buckets. The application will fail if it can not acquire all the required tokens in any one bucket.
Keywords: SLM tokens
References: None |
Problem Statement: CimIO device green/red status indicators do not function correctly on a MES Clustered systems. | Solution: On a MES Clustered environment the CimIO_Gethostname will fail to retrieve the correct node name if the MESCluster\AdsaClusterNetworkName registry key is undefined. To resolve the issue populate the AdsaClusterNetworkName registy key with the cluster node name.
This can also occur if the CimIO Manager port 7777 is blocked between the IP21 and CimIO interface server, or if the CimIO interface is not configured using the CimIO standard method.
Keywords: red dot
green dot
question mark
References: None |
Problem Statement: How to change a ramp variable from a normal ramp to a Programmed Imbalance Ramp? | Solution: Note: if you are unclear about ramp imbalance & programmed ramp imbalance, please have a look at KB: 143542-2.
We assume that you already have a controller deployed & running online.
1. Go to the Web Interface (PCWS) and switch ON the master switch.
2. Navigate to Dependents & identify your ramp variable.
3. Check the tuning of that ramp and ensure that the Maximum Imbalances parameter is set to 10 (this identifies the ramp as a normal ramp that is allowed to be out of balance for 10 constructive cycles before the controller is shut down on ramp imbalance).
4. With the initial tuning in place, change the Maximum Imbalances parameter to -1 (instead of 10). This changes the ramp into a Programmed Imbalance Ramp.
Advantage: a Programmed Imbalance Ramp is to be imbalanced without turning the controller off after n number of cycles unless the magnitude (regardless whether it is a +ve or -ve value) of the imbalance goes outside the calculated imbalance limits (limits of allowed imbalance)
Keywords: Programmed Imbalance Ramp, ramp variable, Maximum Imbalances
References: None |
Problem Statement: How do I ramp a gate valve with no controller?
For this specific sample, it is required to open a gate valve operating in manual (with no controller) from 0 to 100% in 50 minutes. How do I model this system in Aspen HYSYS Dynamics? | Solution: If you do not have controllers, an option would be to use the Event Scheduler to create an opening - closing event. However, Ramp Controller option in the Event Scheduler can only ramp the SP of the controllers. But in this case, we would like to ramp the real open percentage of the vale directly.
The recommendation is then to include a Transfer function to do this job.
In the attached example, a Transfer function block in HYSYS Dynamics is implemented to open valve VLV-102 from 0% to 100% within 50 minutes. The valve opening percentage is defined as the Transfer function's OP, instead of manipulating it through desirable actuator position, and a Ramp function is set accordingly to model the desired system.
To run the model, start the integrator, and click the Start Ramp button as well. You will see the valve VLV-102 opening from 0% to 100% within 50 minutes time.
Keywords: Transfer Function, Ramp, Set Point, Operating Point, Percentage Open.
References: None |
Problem Statement: Which versions of PIPESIM integrate with Aspen HYSYS? | Solution: PIPESIM has released the following versions since 2013:
Date Title
July 2017 PIPESIM 2017 released
November 2016 PIPESIM 2015.2 and PIPESIM 2012.4 released
November 2015 PIPESIM 2015.1 and PIPESIM 2012.3 released
December 2014 PIPESIM 2014.1 and 2012.2 released
August 2013 Released PIPESIM 2013.1 and 2012.1
In August 2013, Schlumberger released a totally new user interface for PIPESIM which no longer supported their OpenLink API. As a result, all 3rd party integrations were broken in the new PIPESIM user interface.
Schlumberger continued to support PIPESIM version 2012 series (2012.1, 2012.2, 2012.3, and 2012.4). Schlumberger customers who wanted to integrate with 3rd parties (Aspen HYSYS, included) had to use this 2012 version.
In November 2016, Schlumberger announced the following:
“PIPESIM 2012.4 will be the last major release of the “classic” user interface.”
Going forward, PIPESIM will integrate with HYSYS and other 3rd party links through their IAM 2017 tool (not yet released).
If customers wish to use the AspenTech PIPESIM links, they MUST use the 2012 version series of PIPESIM -- or they need to reach out to Schlumberger support for additional details regarding 3rd party integrations of their tool.
2017 Update: Schlumberger has released a new version of PIPESIM that supports communication with process simulators via IAM 2017 (released December 2017), but AspenTech has not yet been able to develop a link inside the software to support this latest release.
Key Words
PIPESIM
Keywords: None
References: None |
Problem Statement: How to modify Free Radical and Ziegler Natta Kinetics in Aspen Plus Dynamics? | Solution: Both Free Radical and Ziegler Natta kinetics are supported in open kinetics format in Aspen Plus Dynamics. By default, these reactions are procedure based closed form. To enable open form, please follow:
1. Please go to Global > DynamicsOptions >GlobalPolMethod and select “Equation” option
2. When PolMethod is Equation, each reactor uses the open kinetics object identified by OpenFR (for free radical kinetics) or OpenZN (for Ziegler-Natta kinetics) on the reactor PolymerInputs form.
3. After any modifications are made, please run in initialization and steady state mode.
Key Words
Polymer, Open form, Equation, Parameter
Keywords: None
References: None |
Problem Statement: How do I get the Latent Heat for a mixture on Aspen Plus? | Solution: Since V10, you can use the property sets DHVLMX and DHVLMXMS to report the heat of vaporization for a mixture, on mole and mass basis, respectively, based on vaporizing 1% more of the liquid.
For V9 and earlier versions, you can set up a Flash2 at Operating (or Relieving) Pressure and Vfrac=0. Feed the liquid composition into this block. Send the Liquid from this first Flash2 into a second Flash2 with P=0 and Vfrac=0.01 specifications Run the simulation and calculate the Latent Heat as:
Where,
Qt = the Heat Duty from the second Flash2 block
Qv = the Heat Duty required to generate the Vapor in the second Flash2 block
Ql = the Heat Duty required to Heat the unflashed Liquid in the second Flash2 block
LH = Latent Heat of the initial vapor boiled off
m(Vap) = Mass Rate of the Vapor generated from the Second Flash2 block
m(Liq) = Mass Rate of the Liquid leaving the Second Flash2 block
Cp(Liq) = Constant Pressure Heat Capacity of m(Liq)
T(Vfrac=0.01) = Final Temperature of the Second Flash2 block
T(Vfrac=0) = Final Temperature of the First Flash2 block
These calculations are implemented in the attached bkp file. The bkp file will automatically calculate the Latent Heat using an extra Flash2 block and two (2) Calculator blocks. The user needs to do the following to apply the file to their calculations:
Add the pertinent Components to represent the liquid composition for the case.
Select an appropriate Property Method for the system. See On-Line Help for Guidelines.
Edit the Stream FEED Pressure and Composition to reflect the Applicable system or relieving pressure and the liquid composition.
Run the simulation and obtain the Latent Heat from the Control Panel.
It is not necessary to change the FEED Temperature as this is not used. It is also not necessary to edit the three Flash2 Blocks input. The VFRAC Specification in the VFRAC block can be changed if a value other 1% of the liquid is desired. It is also possible to add a Sensitivity Analysis to investigate the effect of changing the VFRAC spec. The Flash2 Blocks are set up as follows:
The 1st block SATLIQ sets the FEED material at its bubble point Temperature.
The 2nd block VFRAC sets the material at a VFRAC=0.01 to generate 1% vapor. This can be changed as required.
The 3rd block SENSHT gets its TEMP spec set by the Calculator block SATLIQ to match the TEMP in SATLIQ. It accounts for the Ql or the Duty required to heat up the Liquid in VFRAC.
The Calculator block LHEAT uses the results of the Flash2 Blocks to calculate Latent Heat. The results are reported to the Control Panel and the Report File. As mentioned, the Calculator block SATLIQ sets the TEMP spec in the SENSHT block. The Stream Summary for Stream VAP2 reports properties applicable to Relief Valve type calculations.
Keywords: Latent Heat, DHVLMX, DHVLMXS, heat of vaporization.
References: None |
Problem Statement: How to change the background color of HYSYS flowsheet? | Solution: There are two different background color options for HYSYS flowsheet. One background color option is white:
The other background color option is green:
If you want to change the background color, please go to File - Options – Simulation – Formatting. Choose “Default” for the white background color, and choose Classic for the green background color.
Keywords: None
References: None |
Problem Statement: Can I control how many lines are being printed in the Trace Window? | Solution: Yes, object inspect the Trace Window and choose View Trace Properties.
You will be able to set the number of lines printed here.
Keywords: Trace Window, History Length.
References: None |
Problem Statement: Why is the remaining flow ratio not calculated by Petroleum Feeder? | Solution: The remaining flow ratio is not calculated by the Petroleum Feeder when no product stream is attached to the feeder. Make sure a product stream is connected to the feeder so it can calculate the remaining flow ratio to equal the sum to 1.
Keywords: Petroleum Feeder, Flow Ratio
References: None |
Problem Statement: How do I include Ambient Medium Velocity from a pipe segment in a case study? | Solution: To add Ambient Medium Velocity from a pipe segment in a case study, follow the steps given below:
1. Double-click the applicable pipe segment and go to the Rating Tab. Expand Heat Transfer on left and then go to Estimate HTC and Right-click Velocity (either the label or its value) and choose Copy (Ambient Medium must be set as either Air or Water).
2. Next, open the Case Study and go to the Variable Selection tab. Right-click in the Independent Variables input box and select Paste.You should now see the Ambient Medium Velocity listed along with its current value in the box. Set the dependent variable(s) if not done already (for instance, the overall heat transfer for the pipe segment, Q)
Note: Instead of copying and pasting the Ambient Medium Velocity, you can also drag and drop it into the Independent Variables box. Alternatively, right click ‘Send To’ option can be used as shown below.
Keywords: Ambient Medium Velocity, Case Study, Pipe Segment, Air, Water
References: None |
Problem Statement: Why can't vibration analysis be performed for heat exchangers with rod baffles? | Solution: The vibration risk with rod baffles only arises due to limited crossflow near the inlet or outlet. In general, risk of vibration in this type of exchangers are a lot less than baffled exchangers.
It is very unlikely that a rod-baffle unit could suffer from vibration. Over the vast majority of the tube length there is good support and little crossflow, so the effect of the entrance and exit velocities on the entire tube length is likely to be small.
Keywords: Vibration, rod, baffles
References: None |
Problem Statement: I have an ACCE project created by another user with some library files attached. Is there a way to export those library files to my library without having to create a copy manually. | Solution: In ACCE there is an option to export attached spec library files to your library. This helps in easily transferring library files without having to share it separately. Right mouse click on the respective Spec in the Project Basis View and select Export to Library as shown in the attached screenshot. Enter the file name and click on OK. The spec will now be saved in your library.
Key words
Spec, library, export
Keywords: None
References: None |
Problem Statement: What solver settings may be modified to improve a slow running dynamic simulation? | Solution: See the attached word document with a few comments and advices on how to select solver settings to improve dynamic simulation reSolution performance. We will include those comments in the on-line help documentation of Aspen Custom Modeler future versions (planned for v11).
Keywords: dynamic, solver, settings
References: None |
Problem Statement: What are the lower and upper bounds for variables in Aspen Adsorption and how can these be changed? | Solution: If we open the AllVariables table for any block in the flowsheet, we can see the default lower and upper bounds for the variables.These can be changed if required.
Sometimes these lower and upper bound may not be displayed in this table and in that case if we right click on the Headings field and select properties.
KeyWord:
Lower and Upper bound values, AllVariables Table
Keywords: None
References: None |
Problem Statement: I would like to extract the physical properties from the Cooler Performance Tables in HYSYS to a spreadsheet in Excel using VBA. Depending on the process stream sometime heavy liquid is present other time only light liquid is present in the cooler. Is there any way I can define a general code to extract either light liquid, heavy liquid or mixed liquid physical properties? | Solution: Since V8.8 the hysys.tlb was updated to include curve parameter accessors on the cooler, heater, and other interfaces.
With these V8.8 interfaces you can directly access the CurveMixedLiq{PROPERTY}, CurveHeavyLiq{PROPERTY}, and CurveLightLiq{PROPERTY} RealFlexVariables to find the values.
Each RealFlexVariable has a Boolean array IsKnown which indicates if the value is EMPTY or not in the corresponding entry of the values array. You can check against IsKnown for every entry in the array, or just check the first entry and assume that it will be the same for the rest of the array. Below is some sample VBA that illustrates a way the customer can access different liquid properties.
Public Function GetLiquidThermalConductivity(cool As CoolerOp) As Double()
If cool.CurveMixedLiqThermalConductivity.IsKnown(0) Then
GetLiquidThermalConductivity = cool.CurveMixedLiqThermalConductivity.Values
ElseIf cool.CurveHeavyLiqThermalConductivity.IsKnown(0) Then
GetLiquidThermalConductivity = cool.CurveHeavyLiqThermalConductivity.Values
ElseIf cool.CurveLightLiqThermalConductivity.IsKnown(0) Then
GetLiquidThermalConductivity = cool.CurveLightLiqThermalConductivity.Values
Else
Dim unknown(0) As Double
unknown(0) = EmptyValue_enum.HEmpty
GetLiquidThermalConductivity = unknown
End If
End Function
If you are using something older than the V8.8 HYSYS tlb, this can also be achieved using BackDoor interface to the Cooler and a moniker determined from the script manager. For instance, the PsuedoCriticalTemperature moniker is :Temperature.580.#.[], with # being 3 => HeavyLiq, 2 => LightLiq, 4 => MixedLiq, 1 => Vapour. This # correspondence applies for each of the properties.
Keywords: VBA, moniker, liquid phase, mixed phase, library.
References: None |
Problem Statement: What should I do when my Hydrate formation line stops at the Cricondenbar? | Solution: To workaround this limitation of Envelope Analysis, you can utilize the Hydrate Formation Analysis tool along with Case Studies. The idea is to generate a case study of Hydrate Formation temperature against pressure. This article will focus on accessing these tools from the Navigation Pane. Other ways of accessing each tool can be referred to F1 Help resource. Please follow these steps (only applicable to version 8.0 onward):
First, Hydrate Formation temperature must be recognized as a variable by HYSYS. You will use Hydrate Formation Analysis to do this.
From the Navigation Pane > Click on Stream Analysis > Click on Add > From the drop down menu, select Hydrate Formation > On Select Process Stream window, select your target stream to perform the study > Click OK.
Hydrate Formation window will automatically pop-up. Note that on Performance Tab, we now have a variable called Formation Temperature.
Second task is to create a case study using Case Studies tool.
From the Navigation Pane > Click on Case Studies > Click on Add
From the new case study form, click on Find Variables above the Dependent Variables section
From the drop down menu next to Context, select Analysis > Select the Hydrate Formation analysis that was created in previous step > Select Hydrate Formation temperature > Click on the transfer arrow > After the variable has been transferred to Selected window, click Done.
Note: Alternatively to the described step, you can also create a case study directly from Hydrate Formation window. On Performance Tab of Hydrate Formation window, right-click on the Formation Temperature value > Send To > Case Study > Create New. At this point, a case study has been created with Hydrate Formation temperature as the dependent variable. You can navigate to the Navigation Pane > Click on Case Studies, then select the new case study you have created from previous step.
Lastly, you will specify pressure as Independent Variables. You can then proceed on to set up your case study using the range of pressure in interest and the desired method of study. For more information in setting up a case study, please refer to F1 Help resource.
Keywords: Hydrate formation line, hydrate curve, Hydrate utility, Cricondenbar, Case Study
References: None |
Problem Statement: How do I define the default values for both the Grid Spacing and Grid Index for my drawings? | Solution: The settings for both the Grid Spacing and Grid Index of the ABE Drawing Editor are found in the registry. By default, these values are set to 1 mm and 5 for the Grid Spacing and the Grid Index, respectively.
Users may set new values according to their needs in the registry, applying these changes at once through there and therefore avoiding the need of manually setting up their values for each drawing.
The registry key is:
HKEY_CURRENT_USER\Software\Intergraph\Applications\AspenZyqadPFD.Application\PrefSets\AspenZyqad
Keywords: Grid Spacing, Grid Index, Registry, Drawing Editor.
References: None |
Problem Statement: What is the difference between vessel pressure and vessel pressure-dynamic variables accessible for vessels inside a spreadsheet? | Solution: If we select the vessel pressure-dynamic, then when we switch to dynamic mode and if the vessel pressure is checked in the dynamic specification then the pressure that we set in the spreadsheet will be used. But, quite often in dynamic mode the vessel pressure is determined by the surrounding unit operations and fixing the vessel pressure this way may not be a good practice.
If we select the vessel pressure option for export from inside the spreadsheet, then this pressure setting will also be written over the vessel pressure in the dynamics tab for the vessel. But this method does not require the pressure setting to be checked. Consequently, this value will be taken as the initial vessel pressure in dynamic mode, but it will change as the dynamic simulation proceeds.
Keywords: Vessel pressure, vessel pressure-dynamics, spreadsheet
References: None |
Problem Statement: What is the difference between the two similar methods NRTL and NRTL-2 in Aspen Plus? | Solution: The NRTL property method uses:
The NRTL activity coefficient model for the liquid phase.
The ideal gas equation of state for the vapor phase.
The Rackett model for liquid molar volume.
Henry's law for supercritical components.
The NRTL-2 property method uses:
The NRTL activity coefficient model for the liquid phase with binary parameter data set number 2.
The ideal gas equation of state for the vapor phase.
The Rackett model for liquid molar volume.
Henry's law for supercritical components.
This property method is recommended when you need to use two sets of binary parameters in a single calculation run. For example, you can use the NRTL property method for VLE calculations, and the NRTL-2 property method with a different set of binary parameters for LLE calculation (for example, for a decanter).
Keywords: Aspen Plus, NRTL, Methods
References: None |
Problem Statement: I want to populate UFD symbol library. I ca not do this because the system does not see any new folder I have created.
I create the folder “Valves” in the UFD symbology but I don’t see it in the drawing manager.
How do I include a new folder in the Symbol Library displayed in the Drawing Editor? | Solution: Drawing Editor application has a drawing editor template file (XML) that describes the mapping between the logical symbol folders and folders that are shown on the Symbol Library on the application. When adding a new folder inside Symbol folder, you need to update as well the xml files located in the Templates directory.
There are two ways to update the xml file.
Update the XML files located in the Templates folder of the Workspace libraries.
As an example, for the UFD template you need to update the UFD.xml.
Open the XML file using Notepad, and add a new line following the format used for existing lines. In this case:
<Folder Name=Valves State= Path=UFD\Valves/>
2. Save the file and reload the Workspace. You should see the new folder in the Drawing Editor.
XML update using the Drawing Editor application.
Open the Drawing Editor
Click on File -> Drawing Templates
On the the following dialog select the Symbol library you want to update and click on Edit.
The Drawing Editor will display the browser. Go to the Templates folder to see all the existing XML files (named the same as the list displayed on the drop down menu).
Select the XML file of interest and click on Open. This file will display the following dialog
Note: These files are usually persisted out of the box, within the templates folder. Also it important to double check that these files are not marked Read Only).
Drag and drop the folder from the left hand side and drop it on the XML root node on the right hand side of the dialog.
Right click on the folder (In this example, Test Symbols) to select “Wildcard”
Click on Save.
Reload the Workspace on the Admin tool. You should be able to view the newer symbols on the SymbolLibrary, when reopening the Drawing Editor.
Keywords: Symbols, Templates, xml, Drawing Editor
References: None |
Problem Statement: When will either the ‘Convert to Template’ or ‘Template Properties’ options be shown under the Customize | Case section? | Solution: Users may find either the ‘Convert to Template’ option under the Customize | Case section on the ribbon or the ‘Template Properties’ option, depending on the type of simulation file opened in Aspen HYSYS.
The ‘Convert to Template’ will show up only if the simulation file is an Aspen HYSYS case, that is, a file with the *.hsc extension.
On the other hand, the ‘Template Properties’ option will be available if the simulation file is not an Aspen HYSYS case (*.hsc file), but any of the template files: RefSYS Reactors, Compressor Surge, Columns, etc.
Keywords: Convert, Template, Properties, Customize.
References: None |
Problem Statement: How is pressure drop across a RadFrac tray calculated in simple dynamic tray correlation? | Solution: If we specify simple tray correlations, the pressure drop across a tray is related to the volumetric flow of vapor into the tray and the liquid on the tray using the following equation.
Where:
ΔP = Pressure drop across the tray
KO = Orifice constant
ρV = Vapor molar density
ρL = Liquid molar density
QV = Volumetric flow rate of vapor to the tray
gc = Gravitational constant
hL = Liquid level on the tray
The orifice constant, KO, for each tray is fitted so that the initial pressure drop during the dynamic simulation matches that from the steady-state simulation.
Keywords: Simple column hydraulics, Radfrac, pressure drop across tray
References: None |
Problem Statement: What are the limitations of modeling polymer process in Aspen Plus Dynamics? | Solution: Followings are the common limitations encountered modeling polymer process in Aspen Plus Dynamics:
Only one polymer product can be handled.
Only one Ziegler Natta catalyst is allowed, however the catalyst can be single or multi-site.
No emulsion polymerization kinetics is allowed.
Most reaction models are closed form.
Reverse flow calculations are not supported for polymer stream.
Key Words
Polymer, Reaction, Catalyst, Reverse Flow
Keywords: None
References: None |
Problem Statement: Can I calculate the energy required for a mixture to change state from saturated liquid to a specified vapor fraction (i.e. a pseudo Heat of Vaporization)? | Solution: By definition, the Latent Heat of Vaporization of a mixture in HYSYS is the enthalpy difference between the bubble point (Vf=0) and the dewpoint (Vf=1) at a fixed pressure.
If you wish to calculate a pseudo Heat of Vapourization (i.e. energy required) for a mixture to change state from the saturated liquid (Vf=0) to a specified vapor fraction (e.g. Vf=0.05), you have to perform the calculations manually or in a HYSYS Spreadsheet. For example:
Energy (Stream 2, Vf=0.05) (kJ/hr) - Energy (Stream 1, Vf=0) (kJ/hr) / Total Molar Flowrate (kgmol/hr) = Hvap (kJ/kgmol of fluid)
OR
Energy (Stream 2, Vf=0.05) (kJ/hr) - Energy (Stream 1, Vf=0) (kJ/hr) / Vapor Molar Flowrate (kgmol/hr) = Hvap (kJ/kgmol of vapor)
Please review the attached Aspen HYSYS case as reference.
Keywords: Vapour, Vapor, Vapourization, Vaporization, Heat, Latent, Pseudo, Hvap
References: None |
Problem Statement: Saving a snapshot to a folder works without a problem but when a share location is used in place of the actual folder path, the following error can occur: can not access this file. | Solution: Add the user name to the Share Permissions to allow the user access to the share. For manual snapshot saves the logged on user must have share permissions set. For scheduled snapshot saves, the InfoPlus.21 System Account must have share permissions set.
Note: When reviewing the share properties, there is a Security tab which gives access to the folder and a Permissions button for setting the share permissions.
Keywords:
References: None |
Problem Statement: In Exchanger Design & Rating, a calculated pressure drop is reported in TEMA sheet for both shell side and tube side. However, within the Overall Summary, if you sum up the reported pressure drop contributions from different sources, the result is not equal to TEMA sheet value. Why is that? | Solution: The Overall summary is only reporting pressure drop associated with frictional effects (such as nozzles or bundle Xflow). Nevertheless, there is also pressure drop associated with gravitational changes, as well as to acceleration effects (momentum changes due to condensation throughout the heat exchanger).
These contributions are added to frictional pressure drop to calculate the overall pressure drop, which is reported on the TEMA sheet.A full report for all pressure drop sources is displayed in Results | Results Summary | Thermal/Hydraulic Analysis | Pressure Drop
Keywords: Pressure drop differences, TEMA, overall summary, acceleration, gravitational
References: None |
Problem Statement: How can predictions be improved using DMC3 Builder? | Solution: One of the techniques to improve predictions is to analyse the masked/unmasked response curves.
Note: For illustration purposes, we are going to use a Crude Distillation Unit (CDU) as an example, since it is a very well-known process.
The following figure has a bunch of response prediction curves for some CVs.
Predictions look reasonable for most CVs. However, according to the above figure, it is noted that there are some sections with offsets and it is obvious that the CV RX171PV (reactor H2/HC mole ratio, dimensionless) response is not predicted very well (highlighted in orange, in the middle left side). So, this issue needs to be fixed before updating the master model.
One of the curves that was masked is SC151SP (recycle compressor speed, RPM) Vs RX171PV. Nevertheless, as per the uncertainty analysis using DMC3 Builder, this curve has an A grade on both gain and dynamic. In addition, its gain absolute value is not that insignificant. Therefore, it has a great effect on RX171PV. As a result, this particular curve was unmasked to fix the problem. Below is the uncertainty analysis for that curve.
This particular process is very generic so there is neither process description nor PFD. That is why DMC3 Builder features were utilized to address this issue. Now after executing this modification, the prediction of SC151SP Vs RX171PV has very much improved as can be perceived in the following figure.
Now, this prediction is tolerable.
Keywords: DMC3, Predictions
How can predictions be improved using DMC3 Builder?
References: None |
Problem Statement: How to change the display sequence/order of components of a Product in Aspen Petroleum Scheduler?
Requirement is that it should display in the same sequence as the one when the component is added.
The screen-shot below shows the desired configuration:
Go to Model à Products
Select any product and add a component as shown and click ok
2. Go to event screen and add a blend event for the same product. The order of the new component is different than that in step 1
3. Now if you open Model à product again and select U91, the order of components is again different than step 2 | Solution: This refers the setting of display order of components of a Product in APS
APS is working as designed by sorting components in any product according to the value in the SEQ field of the COMPONENTS table in the model Database. When a component is added there is a default value for SEQ that is assigned to the component and the sorting is done according.
The order of components can be set by the user directly in APS through the Reorder Items functionality in the Product dialog or by manually modifying the value of SEQ for the components on the model Database.
Below are the details on how to set a desired order of components for a specific product. Steps 1 - 4 in the attached document mostly reproduce the issue as reported; steps 5 - 10 show the two alternatives of how to set the desired order for product components.
Add test component ABC to model (Model -> Components) as presented in the issue description document.
2. Add test component ABC to product U91 (Model -> Products) as indicated in the issue description document.
Notice that the component is added at the bottom of the list because this is the only space available to add a new component.
3. Click OK to close the Product Dialog and go to Events -> Add Event -> Blend to create a new blend for product U91 and inspect the list of components
As reported, the test component is no longer at the bottom of the list where we originally added it. The test component is the first in the list.
4. Close the blend dialog and go back to Model -> Products, select product U91 and inspect the list of components
The test component is not at the bottom of the list where we add it, but it is in the first position of the list as in the blend dialog.
5. Open the Model Database and look for table COMPONENTS;
Notice that sorting of components for product U91 (or any other product) uses the value in the field SEQ. For example, ABC has a SEQ number of 0, and is therefore placed at the beginning of the component list.
6.Manually modify the entry of SEQ for the test component ABC and make it 20.
7. Save the database, go to APS and close and reopen the model. Now inspect the component list for product U91 in Model -> Products
Notice the component is now at the bottom of the list. This is consistent with the new value for field SEQ for product ABC in the model Database.
8. An alternative to manually modify the Database is to use the “Reorder Items” bottom on the right side of the Product Dialog.
You can bring ABC component up or down and it will have the same effect as modifying the Database SEQ value directly.
9. In this example, we have moved the ABC component just below ALK so it is still the last component in the list, but it’s SEQ number should have changed (no longer 20 as we set it up in step 6).
10. Click OK and close the Component Order and Product dialog. Save the model in APS. Notice that the value of SEQ has changed according to the reordering of items we did in APS.
CONCLUSION:
Thus, the expectation to have the component sequence corresponding to the order in which they added the products can be met by setting the desired sequence through the “Reorder Items” button or directly on the database.
Keywords: Aspen Petroleum Scheduler, Re-order, Component, Sequence, display, Property dialog box, etc.
References: None |
Problem Statement: What is the pressure drop correlation used in the BLOWDOWN utility? Why it’s not used in the pipe segment unit operation? | Solution: For two-phase flow in pipe model in BLOWDOWN, the Friedel correlation is used to determine the pressure drop and liquid hold-up. You could find more details of the Friedel correlation in HYSYS Help menu under Blowdown Technology - Technical reference” – “Piping Pressure Drop and Liquid Holdup Equations”.
This Friedel correlation is not used in HYSYS pipe segment unit operation. BLOWDOWN was developed independently from HYSYS, and should be used for a specific application, i.e. depressuring and blowdown. It is not a general multiphase flow solver like the HYSYS pipe segment, where a larger variety of conditions can be modeled which requires a little more flexibility in the flow model or correlation. In BLOWDOWN situations, single phase flows are more common than two-phase flows in the discharge. The correlation only matters for two-phase flow. If two-phase flow does occur, then it is a good assumption that the gas and liquid will move at the same velocity. Therefore, allowing a different correlation that predicts slip and flow regimes (which all the HYSYS pipe correlations do) is not necessary.
Keywords: BLOWDOWN, Pipe Segment, Friedel correlation,Two-phase flow
References: None |
Problem Statement: How do I view the Sulfur Recovery performance results in Aspen HYSYS-Sulsim? | Solution: The following steps apply only after the simulation has been run and converged successfully.
First, return to the main flowsheet by clicking on the Flowsheet/Modify tab in the top ribbon and then selecting the Go to Parent button.
Locate the Sulsim sub-flowsheet icon.
Then, double-click on the Sulsim icon and select the Performance tab to view the recovery results.
Key Words
Sulsim, sulfur recovery
Keywords: None
References: None |
Problem Statement: Why Aspen Shell and Tube program does not allow to enter the number of tubes? | Solution: The program allows you to enter the number of tubes according to the tube rows and maximum number of tubes per row per pass.
For example, if you enter 8 rows and 4 tube passes, the calculated maximum number of tubes per row per pass is estimated as 19. This means that will need to enter 152 tubes per bundle.
If you instead specify 150 tubes per bundle, the program will give you an error.
Also note that the program doesn’t have an option to enter different number of tubes per row. For example, one row with 7 tubes and another with 9 tubes.
Keywords: number of tubes, rows
References: None |
Problem Statement: How can double wall plate heat exchangers be modelled in Aspen Plate Exchanger? | Solution: Double wall plate exchangers are used in industry to eliminate the risk of fluid leakage from one stream to another within the heat exchanger, as any potential leak will be to the external of the unit. This can be for safety and/or product purity considerations.
This configuration is relatively rare and currently is not implemented in Aspen Plate Exchanger. However, there is a workaround in calculating the performance of the unit in the program. The plate thickness can be increased to represent the double wall and a fouling resistance can be introduced (or increased) to compensate for the air layer between plates.
Keywords: Double Wall plate heat exchanger
References: None |
Problem Statement: How do I change the scale of a drawing? | Solution: The scale of drawing can be changed by selecting the Scale icon from the Modify tool bar.
If the Modify tool bar is not active by default, you can activate it from View | Toolbars... | modify.
Keywords: scale factor, drawing, enlarge, reference
References: None |
Problem Statement: Is it possible to add Non-Newtonian fluids in Exchanger Design & Rating? | Solution: Newtonian fluids have the relation between local shear stress and shear rate (gradient, transverse to the flow direction, of the local velocity) which defines the viscosity:
For a power law Non-Newtonian fluid, the relation is:
This means that effective viscosity is a function of shear rate:
Where:
K Consistency coefficient Pa*sn
n Power index
η Viscosity Ns/m²
γ Shear stress rate 1/s
τ Shear stress Pa
- If n is unity, the fluid is Newtonian.
- If n is above unity, the fluid is shear-thickening (pseudoplastic).
- If n is below unity, the fluid is shear-thinning (dilatant).
The Parameter K can vary with temperature quite significantly (like viscosity). Variation of n with temperature is usually small.
Only in Aspen Plate Exchanger single phase liquid streams can be specified as being non-Newtonian by setting the Physical Property Package to User Specified Properties.
The non-Newtonian parameters, shear rate exponent n, and parameter K can then be entered in the Stream Properties table. Values of viscosity then become effective viscosity as defined in non-Newtonian fluids.
Keywords: Non Newtonian fluids, plate exchanger, viscosity
References: None |
Problem Statement: Can I access PFR results via Automation? | Solution: Currently the PFR object (PFReactor in the HYSYS type library) does not have properties for all the results that are available in the interface. However, these properties can be accessed via Backdoor variables. In this method the internal monikers (pointers to the information) are used to access the variables.
The attached Excel example includes code to retrieve all the results that are available in the interface. Also included is a HYSYS 2.4.1 file that includes an example PFR Reactor.
NB Backdoor methods are only recommended when there is no other alternative, the internal HYSYS monikers may not remain constant between versions so care should be exercised when upgrading
Keywords: PFR, Reactor Results, Backdoor, Moniker
References: None |
Problem Statement: How do I input a condensation/vaporization curve in Aspen Shell & Tube Exchanger? | Solution: Select 'User specified properties using heat loads' option; with this option the cumulative heat load is used to determine the duty of the stream. A reference mass flowrate for the specified heat load is entered, where the entered heat load is divided by the reference flowrate to determine the change in specific enthalpy.
Why do User Specified properties with heat load only have one pressure level?
Keywords: Vaporization Curve, Condensation Curve, Cumulative Heat Load, Specific Enthalpy.
References: None |
Problem Statement: Can a user specify different duties for each coil in a Fired Heater in Aspen HYSYS to meet design specifications? | Solution: In Aspen HYSYS, a fired heater model always distributes the duty almost equally. The simple fired heater model HYSYS in steady state. It distributes the heat evenly among the radiant zone streams (and ignoring the convective/economizer zone streams). That is to say, the change in heat flow from inlet to outlet is the same for each of the streams.
If you want the different streams to be heated by different amounts, the only workaround would be to heat one of the streams in the fired heater and to send other streams through a series of heat exchangers to heat the other streams to the desired amount.
Keywords: Fired Heater
Exit Temperature
Heat Duty
Different Coils
References: None |
Problem Statement: Equations and Benchmark calculations of relief loads for emergency scenario | Solution: The attached document provides a hand made validation for the calculated relief loads inside the Safety Analysis Environment. The emergency scenarios included are:
1. Control Valve Failure
a. Vapor Equations
b. Vapor Example with Unchoked Flow
c. Vapor Example with Chocked Flow
d. Liquid Equations
e. Liquid Example with Unchoked Flow
f. Liquid Example with Chocked Flow
2. Heat Exchanger Tube Break
a. Vapor Equations
b. Vapor Example with Unchoked Shell-Into-Tube Flow
c. Vapor Example with Choked Tube-Into-Shell Flow
d. Liquid Equations
e. Liquid Example with Tube-Into-Shell Flow
f. Mixed Two-Phase Flow Equations
g. Mixed Phase Example with Unchoked Tube-Into-Shell Flow
h. Mixed Phase Example with Choked Shell-Into-Tube Flow
3. Hydraulic Expansion
a. Equations
b. Example
4. Fire
a. Wetted Fire Equations
b. Wetted Fire Example with a Vertical Vessel
c. Wetted Fire Example with a Horizontal Vessel
d. Wetted Fire Example with a Spherical Vessel
e. Unwetted Fire Equations
f. Unwetted Fire Example
Keywords: PSV, PRD, Relief Sizing, validation, whitepaper
References: None |
Problem Statement: I have a HYSYS model of a column with internals. When I try to export the column to KG-TOWER, the sections do not have the correct trays.
For example, in the figure above, section CS-1 starts from stage 10 and ends at stage 1. However, when exporting to KG-Tower, section CS-1 was from stage 26 to stage 35. | Solution: The default choice for column stage numbering in HYSYS is Top down. If you choose the Bottom up option for stage numbering, then the sections will not have the correct tray numbering when you try to export to KG. You need to change the stage numbering back to Top down under Design tab - Connections.
After changing the stage numbering to Top down, the export tray number in KG-Tower will match.
Keywords: Stage numbering
KG-Tower
Internals
Column section
References: None |
Problem Statement: This an an example on how to get ODM (BPC) data from the s95 web service into aspen SQLplus.
The example below will retrieve the name and description of a ODM equipment object.
Note: Please note that Microsoft SOAP client is 32-bit only, in order to run on a 64-bit Infoplus.21 you'll need to use the 32-bit SQLplus executables
Please see the following article on how to install the 32bit executable: https://esupport.aspentech.com/S_Article?id=000045570 | Solution: To run this example first copy and paste the code into the aspen SQLplus query writer. Second replace the nodename becks2 with the node name of your ODM webservice and the equipment name Edmonds with an equipment name that exists in your database.
LOCAL obj_soap,
wsdl_file CHAR(160),
varArray,
varItem,
valueNames,
InstanceIdentifier string,
valueTime timestamp,
i,
x,
temp ;
wsdl_file='http://becks2/BPCS95WebServicesAnonymous/BPCS95WebService.asmx?WSDL';
BEGIN
obj_soap = createobject( 'MSSOAP.SoapClient30' );
obj_soap.MSSoapInit( wsdl_file );
redim(valueNames,1);
valueNames[0] = 'Name';
valueNames[1] = 'Description';
valueTime = getdbtime;
InstanceIdentifier = 'Equipment.Equipment(Edmonds)';
varArray = obj_soap.Get(InstanceIdentifier, valueNames, valueTime);
WRITE 'Instance Identifier : ' || varArray.item(0).text;
varItem = varArray.item(1);
for each i in varItem.childnodes do
temp = '';
for each x in i.childnodes do
if temp <> '' then
temp = temp || ' : ' || x.text;
else
temp = x.text;
end;
end;
write temp;
end;
WRITE '';
WRITE 'Raw XML';
WRITE varItem.xml;
EXCEPTION
Write 'Error Text : ' || ERROR_TEXT;
Write 'Error Code : ' || ERROR_CODE;
Write 'Error Type : ' || ERROR_TYPE;
Write 'Error Column : ' || ERROR_COLUMN;
Write 'Error Line : ' || ERROR_LINE;
Write 'Error File : ' || ERROR_FILE;
Write 'Error WCode : ' || ERROR_WCODE;
END
Keywords: SOAP
Aspen SQLplus
References: None |
Problem Statement: How can I activate/deactivate a Design Spec from ASW? | Solution: To activate/deactivate Design Specs from ASW please make sure the Aspen Plus simulation and ASW are already connected. After that, please follow the next steps:
1. In Aspen Plus, go to Flowsheet Options | Design Specs and select the Design Spec(s) you want to connect to ASW
2. Right-click on it and copy it:
3. Go to ASW | Organizer | Model Variables | Right-click and select Paste Variables from Clipboard
4. Select the variables you just paste, right-click on them and select Create Table, then select a location for the table in the spreadsheet.
5. The Simulation Workbook Table Wizard will appear. Go to Columns | Click on Add | Select the 'Enabled' attribute | Click on Finish:
6. This attribute (Enabled) has two possible values, 0 or 1; 0 stands for Inactive and 1 for Active. If the Design Spec is Active, it should have a value of 1, so you only need to change it to 0, which will also change the Status to Inactive in the Aspen Plus interface:
Keywords: Design Spec, ASW, activate, deactivate, simulation workbook
References: None |
Problem Statement: Example of a user KLL Distribution Coefficients (USRKLL) subroutine for an Extract block | Solution: Attached is an example of using a USRKLL subroutine for an Extract block. A Fortran compiler is needed to compile and run this example. The backup file will run in V7.3 and higher.
This routine is an illustration of an Aspen Plus user-defined KLL routine for the Extract unit operation block. The liquid-liquid distribution coefficient (KLL) is calculated for water, benzene, methanol and ethanol based on a simple correlation. KLL is defined as the mole fraction ratio for each component in the second liquid phase divided by its mole fraction in the first liquid phase.
The coefficients for the KLL polynomial must be defined on the Extract Properties KLL Subroutine sheet or with the REAL Extract block input language sentence. The KLL correlation used in this example was calculated from the Aspen Plus Unifac liquid-liquid physical property option set. The correlation is valid up to a mole fraction of of 0.3 for both methanol and ethanol.
See Chapter 16 of the Aspen Plus User Models
Keywords: None
References: Manual for details on the subroutine call. |
Problem Statement: How do I model control valve hysteresis? | Solution: Currently there is no valve hysteresis feature for control valve. However, it is possible to set up hysteresis for a valve in Dynamics using some auxiliary blocks and a bit of data manipulation.
Ideally, you would want to be able to define separate characteristics curves for Cv depending on the direction of the valve OP. In the attached HYSYS case (built in V8.8), the idea is to change the value of Cv if the valve is closing and change it back when the valve is opening. In this way, you can get different flow rates from the valve at the same OP depending on its past position.
The transfer function is used to simulate a delay (equal to integration step size) so that you keep track of the valve OP at the previous time. Then, you subtract it from the current OP to get the direction of the move. An Event Scheduler is set up such that it detects when the OP changes. It also detects the direction of change using two events. Based on the direction, it adjusts a coefficient in the spreadsheet that will act on the valve Cv.
Note 1: Pressure-flow and logical operations must have the same execution frequencies (Integrator options) so the delay function is synced with valve OP changes.
Note 2: In Transfer Function, Dead Time must be the same as step size per Execution frequency of logical operations.
It is possible to design more complicated hysteresis schemes by defining the Cv as a function of more parameters (like a nonlinear curve) in the spreadsheet and adjusting them in a similar manner.
Keywords: Control Valve, Hysteresis, Event Scheduler
References: None |
Problem Statement: Relief Valve Sizing in Aspen HYSYS: Benchmark with Examples | Solution: In the attached document, the couple of hand calculations are provided to benchmark the vapor, steam and liquid calculations for HYSYS PSV according to API 520. Using the downloaded demo file and this walkthrough, the user will learn how to properly use relief valve sizing in Aspen HYSYS v8.3 to design, size, and document pressure safety valves. The appendix at the end provides all the equations used in sizing and some examples.
The attached file includes:
1. A starter file;
2. A benchmark HYSYS file;
3. A benchmark pdf file.
Keywords: PSV, Aspen HYSYS, API 520, API 521, API 526
References: None |
Problem Statement: Where can I find the thermodynamic model GERG2008 for an LNG model? | Solution: GERG2008 is not a fluid package available in the Aspen HYSYS library.
You can find GERG2008 by selecting Aspen Properties in Aspen HYSYS and selecting Property Package Filter as All.
Keywords: GERG2008, fluid package, Aspen HYSYS library
References: None |
Problem Statement: The Watchdog Countdown is a very useful parameter for an APC application. On DMC3 builder setting this parameter is different from the way it is set on DMCplus and this could lead into confusion. This tech tip attempt to clarify how to find and set this parameter. | Solution: 1.- On the Calculations tab from the controller three, select User entry and then General, by scrolling down the Built-in entries the Watchdog Countdown parameter can be found. However, the parameter cannot be modified from this view. TheSolution to this is by selecting the Deployment tab from the controller three, and click on Online setting located on the Deployment View Tab. From here under General Setting the Watchdog Countdown should appear and it will show to fields that can be modify the Watchdog Countdown Value and the Cycle offset. The Value field can be modified and then go back to the Calculations view to check that the value now has change.
2.- On the Deployment tab from the Controller three select IO Tags located on the Deployment view tab. Then select the Variable Name General, this will display the Variable details for the General Variable and will show the parameter Watchdog Countdown. However, If this parameter is not show this way select customize from the top ribbon option and in the displayed list look at the bottom of the list for Watchdog Countdown. Check the box for this parameter and click OK.
3.- Finally, Configure the IO source, IO Tag and IO datatype before deploy the controller
Keywords: DMC3, Watchdog Countdown
References: None |
Problem Statement: How do I resolve error C:\Program Files (x86)\ApenTech\Aspen Simulation Workbook VX.X\ASWXLAddinLoader.dll is not a valid Office Add-in? | Solution: First, you need to verify the version of Office that is being used. ASW V10 and prior are not compatible with Office 64-bit, only with 32-bit. V10.1 has implemented compatibility with Office 64-bit
If the version of Office is 32-bit, you need to follow these steps to solve this issue:
1. Run Aspen Excel Add-In Manager as administrator.
2. Uncheck all the Aspen Excel Add-ins and click on OK.
3. Open Excel and verify the Add-ins are inactive.
4. Run Aspen Excel Add-In Manager VX as administrator
5. Check the latest Aspen Excel Add-ins and click on OK.
6. Open Excel and verify the Add-ins are active.
If you are not able to install the 32-bit version of Microsoft Office, you can request the ASW V10.1 installer. This new version brings the new feature that is compatible with Office 64-bit.
Keywords: Aspen Simulation Workbook, Office, Add-in, ASW, ASWXLAddinLoader.dll
References: None |
Problem Statement: Why do I see Incompatible Fluid Package error message when using Oil and Gas Feed? | Solution: When you are using the Oil & Gas Feed for a material stream, sometimes you may see a warning message: Incompatible Fluid Package.
It’s because you do not have any hypo components in the associated components list. Oil & Gas Feed is used define stream composition as a mixture of oil and gas. You could define an Oil & Gas Feed with Bulk Oil Properties (like density, water-oil ratio, viscosity, etc.). However, you will have to define hypo components in the component list, so that the Oil & Gas Feed could adjust the properties of the Hypos to match the properties you set. If all components in the list are pure components, then the bulk stream properties will be fixed from the fluid package calculation, and could not be adjusted.
You could add hypothetical components to the component list by selecting “Hypothetical”. You need to input at least the boiling point information and then click “Generate Hypos”. Then just click Add' icon to add the selected hypos to the component list.
Keywords: Oil & Gas Feed
Incompatible Fluid Package
Hypothetical components
References: None |
Problem Statement: What can be set up through ‘Template Properties’? | Solution: The Template Properties feature (Customize | Template Properties) is active only for template files (RefSys reactors, compressor surge, columns, etc.) and allows users to have more control over template variables.
Installed Simulation Basis allows users to change the Fluid Package basis to either internal or external. Mostly used when working with RefSys reactor templates.
With Exported Variables, users can add internal template variables to the list and save the template. Once such template is imported into a separate case, users can view the variables from a main flowsheet level. There is no much use of it as users can dive down into the template to find the same variables.
Keywords: Template Properties, Variables, Installed Simulation Basis, Exported Variables.
References: None |
Problem Statement: PCWS allows to customize the Operations and Engineering View for the DMCplus controllers and other APC applications. This | Solution: is a quick guide to show how the views can be customize from the Web Page.
Solution
1.- On the webpage go to the configuration Tab
2.- In the left hand option Refer to Column Sets. This option would enable to see a list of all APC applications. Then select DMCplus.
3.- In the Top ribbon you will see two option one for category and the other one for the DMCplus colums set to edit. In this last option can select which view is desire to modify.
4.- Finally, select the Colum that is wanted to add from the available list and click on the >> button to send this option to the selected list. Click on apply and Accept the changes. A success message should appear after this has been done. Then refresh the page and confirm that the option is available to see.
Keywords: PCWS
References: None |
Problem Statement: Are Stagnation Energy and Energy Flow the same? | Solution: Stagnation Energy and Energy Flow are defined as follows:
Stagnation Energy = Enthalpy * Flow
Energy Flow = Stagnation Energy + Kinetic Energy
So, with the definitions above, it is easy to realize that Stagnation Energy and Energy Flow will have the same value if the Kinetic Energy term is disabled, so Kinetic Energy will not be accounted for in the energy balance. Such Kinetic Energy term may be enabled / disabled right on the Home | Options (or Calculation Settings) | General form.
As an example, the following two screenshots illustrate the case in which the kinetic energy term is disabled, so that Stagnation Energy and Energy flow are the same.
On the other hand, the following screenshots illustrate the case in which the kinetic energy term is enabled for the same flare network model, so that Stagnation Energy and Energy flow are not the same anymore.
Keywords: Stagnation Energy, Energy Flow, Enthalpy Flow, Kinetic Energy.
References: None |
Problem Statement: How do I model a heat exchanger with a minimum or maximum fluid velocity through the tube side? | Solution: There can be cases where a minimum or maximum fluid velocity specification has to be fulfilled in a heat exchanger to avoid future issues. For example, a minimum velocity to reduce fouling, or maximum velocity to minimize erosion.
When running a Design case in Exchanger Design & Rating, it is possible to specify upper and lower limits for fluid velocity in the tube side.
To modify this go to Input | Program Options | Design Options | Process Limits | change limits for Maximum and Minimum fluid velocity for either hot or cold side (only the tube side will be available, so one of them will be greyed out):
Keywords: EDR, maximum fluid velocity, minimum fluid velocity
References: None |
Problem Statement: Run-time error ' 521' Can't open Clipboard. This error message is normally seen when using DMCplus SmartAudit or Uncertainty Analysis. The upcoming windows either don't open or the program is closed immediately. Typically, it occurs a lot when using DMCplus applications from a remote session. | Solution: Solution#34088 and #9949 explain 2 methods to solve this issue.
If it's not resolved, we could find rdpclip.exe process in Windows Task Manager, and End process (Kill the process). After the process is killed, SmartAudit and Uncertainty Analysis is supposed to be good to open.
Rdpclip.exe is the main executable for File Copy. It provides function for the Terminal Services server that allows you to copy and paste between server and client. Please always remember to go to: c:\Windows\system32 and find rdpclip.exe and double click on it to re-start the process after SmartAudit and Uncertainty is opened because it is an significant windows process.
Keywords: Run-time error ' 521'
Can't open Clipboard
SmartAudit
Uncertainty
Remote
References: None |
Problem Statement: How do I set up a Case Study in Aspen Plus? | Solution: In order to create a Case Study in Aspen Plus, first create a Sensitivity Analysis. From the Simulation Environment Navigation Pane, expand the Model Analysis Tools Folder and then select the Sensitivity Folder. Then click New and enter an ID.
In this example, we will research a simple heat exchanger where a liquid stream is being heated. Our goal is to observe the effect on the outlet temperature (dependent variable) based on varying the following three manipulated (independent) variables:
1) Process stream flow rate
2) Process stream inlet temperature
3) Heat duty
In a normal Sensitivity Study, varying three independent variables could potentially create a large grid displaying every possible combination of values. In this study, we are assuming there are five real-world operating conditions that need to be evaluated. Therefore, we will only evaluate those specific five scenarios instead of running a full Sensitivity Analysis across the entire range of trials.
The new Sensitivity Analysis will open and display the Vary tab. Check the box next to Case study. This will unlock the Cases tab. Before leaving the Vary tab, specify the independent variable(s). In this case, we will add the heat exhanger heat duty, inlet stream temperature, and inlet stream flowrate. Note that all three of these parameters are input values in this example. The best practice is to only select inputs as manipulated variables.
Next, go to the Define tab to specify the dependent variable(s). For this example, we will add the outlet stream temperature.
Once complete, go to the Tabulate tab and click the Fill Variables button.
Then, go to the Cases tab to input specific values for the independent variable(s) which were specified on the Vary tab. In this example, we will be studying five possible operating scenarios. Individually set the values for the independent variables on a case-by-case basis.
After setting up the desired cases, run the simulation. The solver will now process the cases by adjusting the independent variable(s) and recording the results of the dependent variable(s). To view the output after the run has completed, click on the Results form under the Sensitivity Analysis from the Navigation Pane.
By default, the base case (the original input values from the main flowsheet) will be reported last.
Keywords: Sensitivity, case study
References: None |
Problem Statement: How to model more than 10 convection banks in Aspen Fired Heater? | Solution: In Aspen Fired Heater (from the Exchanger Design & Rating, EDR, suite), it is only possible to model a maximum of 10 convection banks per model when you work with the EDR interface standalone.
However, it is possible to use the Activated feature to integrate EDR with Aspen HYSYS and connect two (or more) different EDR files, each one with a limit of 10 convection banks.
Each EDR file will be attached to a particular Fired Heater block within HYSYS. The key step here is to define the appropriate connections in the HYSYS simulation between the Fired Heater models to accurately represent the arrengament of both the Process stream and the Flue Gas stream from the real equipment.
The attached HYSYS file has an example of the above, where two Fired Heater blocks are connected in series to represent one real equipment. Each block has its own EDR file (which could be essentially the same but with a different name), and each one of these can have its own specifications regarding convection banks.
Process stream and Flue Gas stream have been connected in a counter-current arrangement to represent accurately the real behavior of the equipment (where Process stream will enter the top bank first, and the bottom bank last, while the Flue Gas stream will be in contact with the bottom bank first, and the top bank last).
Keywords: Fired heater, convection banks, EDR, HYSYS
References: None |
Problem Statement: What deviations from the original literature source are present in the Aspen HYSYS implementation of MBWR? | Solution: The Aspen HYSYS Modified Benedict-Webb-Rubin (MBWR) equation of state is implemented based on NIST’s program from 1992.
MBWR uses Wilke's method for the calculation of the viscosity of mixtures and NIST’s formula for that of a pure component in the vapor phase. While, in comparison with the Benedict-Webb-Rubin-Starling (BWRS) equation of state, BWRS uses the default HYSYS viscosity model.
For pure components, the NIST formula is used for the calculation of the thermal conductivity. For mixtures in the vapor phase, a mole fraction average is used. On the other hand, the BWRS method uses the default method for the calculation of the thermal conductivity.
The NIST MBWR 1996 implementation is the earliest version of ‘RefProp’. The latest RefProp method has been added to Aspen HYSYS in recent releases (via Aspen Properties property packages). Use the following link for more information:
https://www.nist.gov/programs-projects/reference-fluid-thermodynamic-and-transport-properties-database-refprop
RefProp 9.0 and higher versions are available in Aspen HYSYS, which provide more accurate results than previous RefProp releases. We recommend users to use the latest RefProp fluid packages instead of MWBR.
Keywords: MBWR, BWR, RefProp, NIST.
References: None |
Problem Statement: I am getting Unable to start solver calculation: No calculable sources. What does it mean? | Solution: The message Unable to start solver calculation: No calculable sources is due to the following possible reasons.
Firstly, user should check the sources mass flowrate. User may have all sources with zero mass flow. In order for the program to run, user should set the mass flow of at least one source to non-zero.
Secondly, user should check the “Selected Scenarios” in the calculation setting editor. User may have not checked the required scenarios to run and needs to make sure at least one scenario is selected for calculation.
Keywords: Sources, mass flowrate, Scenarios, solver
References: None |
Problem Statement: How does Aspen HYSYS calculate Cp and Cv? | Solution: How does Aspen HYSYS calculates Cp?
Cp is calculated rigorously from the molar enthalpy - temperature relationship. How enthalpy is calculated depends on the thermodynamic model being used. (See the Aspen HYSYS Help guide for a full description.)
How does Aspen HYSYS calculates Cv?
CV is calculated by Aspen HYSYS in order to get Gamma. There are three methods used for calculating CV:
1. Rigorous method. Aspen HYSYS calculates CV using the following equation:
Cp - Cv = -T * ((dV/dT)_P)^2 / (dV/dP)_T
where T = Temperature, V = Molar Volume, P = Pressure. (See attached Word document for a derivation of this equation from first principles.)
If this method fails, then Aspen HYSYS reports the semi-ideal value.
2. CV (Semi-Ideal). CV value is calculated as CV = CP – R (CP is calculated by specified fluid package).
A semi-ideal value will also be calculated when:
Stream has a solid phase
Magnitude of dV/dP < 1x10^-12 (because this cannot be distinguished from round off errors)
CP / CV < 0.1 or CP / CV > 20, since this is outside of the range of applicability
3. Cv (Ent. Method). Method maintained purely for historical purposes and was initially added to Aspen HYSYS to be an improvement over method 2 above.
The attached Word document includes a full derivation of the equation above.
Note that when Aspen HYSYS calculates compressors/expanders, it does not use the calculated Cp/Cv value explicitly; instead it uses enthalpies, entropies, and densities calculated directly from whichever property package is selected.
Keywords: Cp, Cv, Gamma, Heat Capacity
References: None |
Problem Statement: Visual studio 2010 crashes when loading from AtBasicPlots.ocx | Solution: There is a problem with DEP (Data Execution Prevention) on Windows 7 when using a 3rd party VSFlex7L.ocx grid control used by AspenTech Legend control (AtLegend.ocx). It only seems to occur when the control is used in custom applications, or from certain web pages.
This issue can be resolved by turning DEP off:
- Open a command prompt “Run as Administrator
- Type bcdedit.exe /set nx AlwaysOff
- Reboot.
To switch DEP back on if required:
- Type: bcdedit.exe /set nx AlwaysOn
- Reboot.
Keywords:
References: None |
Problem Statement: How can a flowsheet be optimizated using sequential modular mode? | Solution: Attached is an example of a user kinetic subroutine for an RCSTR.
This file will run in V7.3 and higher.
The simulation includes two RCSTR reactors. One uses the standard Power Law expression. The other uses a User kinetic routine of the Power Law expression. A Fortran compiler is needed to compile and run the subroutine.
Reaction
Acetone + Allyl Alcohol -> N-Propyl Propionate
r = K*EXP(-E/RT)*CA*CB**0.5
Where
CA = Concentration of Allyl-Alcohol, in kmol/m3
CB = Concentration of Acetone, in kmol/m3
Pre-Exponential Factor = 52860000 m3**0.5/kmol**0.5-Sec
Activation Energy = 62E6 J/kmol
Keywords: None
References: None |
Problem Statement: How do I set up a Case Study in Aspen Plus? | Solution: In this example, we will research a simple heat exchanger where a liquid stream is being heated. Our goal is to observe the effect on the outlet temperature (dependent variable) based on varying the following three manipulated (independent) variables:
1) Process stream flow rate
2) Process stream inlet temperature
3) Heat duty
In a normal Sensitivity Study, varying three independent variables could potentially create a large grid displaying every possible combination of values. In this study, we are assuming there are five real-world operating conditions that need to be evaluated. Therefore, we will only evaluate those specific five scenarios instead of running a full Sensitivity Analysis across the entire range of trials.
Please see the attached example file.
In order to create a Case Study in Aspen Plus, first create a Sensitivity Analysis. From the Simulation Environment Navigation Pane, expand the Model Analysis Tools Folder and then select the Sensitivity Folder. Then click New and enter an ID.
The new Sensitivity Analysis will open and display the Vary tab. Check the box next to Case study. This will unlock the Cases tab. Before leaving the Vary tab, specify the independent variable(s). In this case, we will add the heat exhanger heat duty, inlet stream temperature, and inlet stream flowrate. Note that all three of these parameters are input values in this example. The best practice is to only select inputs as manipulated variables.
Next, go to the Define tab to specify the dependent variable(s). For this example, we will add the outlet stream temperature.
Once complete, go to the Tabulate tab and click the Fill Variables button.
Then, go to the Cases tab to input specific combination of values for the independent variable(s) which were specified on the Vary tab. In this example, we will be studying five possible operating scenarios. Individually set the values for the independent variables on a case-by-case basis.
After setting up the desired cases, run the simulation. The solver will now process the cases by adjusting the independent variable(s) and recording the results of the dependent variable(s). To view the output after the run has completed, click on the Results form under the Sensitivity Analysis from the Navigation Pane.
By default, the base case (the original input values from the main flowsheet) will be reported last.
Keywords: Sensitivity, case study
References: None |
Problem Statement: How do I find iso-hexane, iso-heptane, and iso-octane components in HYSYS databank? | Solution: Components can be found searching by Full Name/Synonym
· Iso-hexane as 2-MethylPentane or as 2-MC5. You can compare the CAS number of this component for iso-hexane: 107-83-5.
· Iso-heptane as 2-MethylHexane or 2-MC6. CAS number: 591-76-4.
· Iso-octane as 2,2,4-TrimethylPentane or 224-Mpentane. CAS number: 540-84-1
Keywords: iso-hexane, iso-heptane, iso-octane, component list
References: None |
Problem Statement: How do I adjust the Equipment Setting Labor for an entire project? | Solution: In order to change the Equipment Setting Labor Hours for the entire project:
Go to the Project Basis View tab
Find Indexing (under the Basis for Capital Costs folder)
Right Click Indexing -> Click on Select
Click Default -> Then Click OK
Right Click Indexing again -> Click Edit
Click Man Hour -> Click Modify
Change the number next to Equipment* (for instance, type 200 instead of the default 100 to double Equipment Setting Labor Hours)
*Note: If you click the arrow, you can adjust the Equipment Setting Labor Hours for specific types of equipment individually
Click OK
Re-evaluate your equipment and you should see your Equipment & Setting man hours adjusted
Keywords: Equipment, Setting, Labor, Hours, Adjust, Adjustment, Indexing, Man Hour
References: None |
Problem Statement: How do I change the password for the broker service that uses a local system account? | Solution: This account is created during install, and if the password has been updated, please make sure to change the password in the following three places.
Administrative Tool Services
Navigate through Control Panel | Administrative Tools| Services
Right click on AZ191Broker and select Properties. Note that for V10 the name of the broker is AZ191, for V9 is AZ181, and for V8.8 is AZ171.
Select Logon tab and type the new password in.
Restart the AZ Broker.
Component Services. AZ Broker.
Navigate through Control Panel |All Control Panel Items| Administrative Tools| Component services.
Expand Component Services | My Computer | DCOM Config
Right-click on Aspen Zyqad 191 Broker and select Properties (Please note to select the correct version of ABE Broker).
Select Identity tab and type password in.
Component Services. AZ Server.
Navigate through Control Panel |All Control Panel Items| Administrative Tools| Component services.
Expand Component Services | My Computer | DCOM Config
Right-click on Aspen Zyqad 191 Server and select Properties (Please note to select the correct version of ABE Server).
Select Identity tab and type password in.
Keywords: Identity, log in, account, Broker, Server, launch, restart
References: None |
Problem Statement: How to customize External Fittings file in ACCE? | Solution: Users can use the external Fittings file to create customized rules. These rules apply only to BPIPE components (in V10.1 - they can be applied to Installation Bulk Pipe). The instructions for how to use the file are included in the file itself. To access the external file:
RMB on the Fittings External File:
Select the file they want to use:
3. RMB again on Fittings to Edit the file (the selected file will open in a text editor):
Once they enter their specifications (they can also do this in library mode), they must specify which piping component(s) they want the rules to apply to:
Keywords: Customize fittings file, customer external file
References: None |
Problem Statement: Severe error in Aspen Plus columns without a condenser: “A liquid feed/pumparound to the top stage is required” | Solution: When you set up a column block without a condenser, as in the picture below, a liquid feed stream in stage 1 or a pumparound to the same stage is a required input for the model.
If you connect the top stage of the column to a tear stream from a recycle or to a pumparound defined using a side stream, you may get a severe error:
SEVERE ERROR
A LIQUID FEED/PUMPAROUND TO THE TOP STAGE IS REQUIRED WHEN Q1=0 IS SPECIFIED IN COL-SPECS; REQUIRED FEED/PUMPAROUND HAS ZERO FLOW
As there is a recycle, Aspen Plus automatically introduces a solver block that calculates the conditions for the tear stream. Initially, in the convergence sequence, this stream has no flow assigned yet is the first stream that the solver executes. As a result, when calculations start Aspen Plus finds know flow in that stream and this triggers the error that gets registered. Afterwards, the solver block comes into play and assigns flow for the first iteration attempt, then calculations can progress normally. However, the severe error will be still visible in the control panel.
However, If Aspen Plus continually by-passes the block, then no flow will be calculated for the stream and at the end of the solve sequence the block will have no results. If this happens then the severe error warning displayed at the start of the solve sequence will persist at the end.
This might especially be the case if the stream connected to the top stage inlet of the Column is a recycle stream and depends on the Column output in order to to have results. To kick-start the column calculations, there has to be flow calculated for the top stage outlet.
One way to ensure this, is to configure a Pump-Around stream such that the return is to Stage 1, the draw can be from any stage. The Pump-Around can either be a partial or total draw. If configuring a partial draw Pump-Around, make sure to provide a flow spec. This can be a small estimated flow value just to initialize the calculation. A thermal spec (Temperature, Temperature Change or Duty) is required for either Pump-Around type. For the purpose of initialization, Temperature change is a better spec than either Temperature or Duty.
After configuring the Pump-Around, re-run the simulation and notice that the Column is no longer bypassed. If the flowsheet fails to converge, it might be because the Column block is holding on to previous bad results so reset and then run. Once the flowsheet is converged, you can select reconcile streams to initialize values for the original Column top stage feed stream and delete the Pump-Around. This way, the liquid top stage feed needed by the column, will be fully defined before the convergence sequence starts and the error will longer appear.
Solutions 108012-2 and 102354-2 explain how and when to do a reconciliation.
Keywords: RadFrac, distillation, severe error, required feed/pumparound has zero flow.
References: None |
Problem Statement: How are methods and rules arranged in the Select Method and Select Rule dialog boxes opened from Explorer? | Solution: The methods and rules are arranged alphabetically by the name of the Visual Basic routine and not by the Module Name or Display Name.
To demonstrate this functionality, create the following local methods:
If the list were arranged alphabetically by either the Module Name or the Display Name, the list would be:
1. cddp
2. zyqad
But as you can see from the list below, the order is different.
Which means that the order comes from the name of the AZMethod
1. AZMethod NameItem (DisplayName = zyqad)
2. AZMethod zyqad (DisplayName = cddp)
If you are able to change the name of the methods and rules, you should set the display name as the AZMethod or AZRule name and this would arrange the lists as desired.
Keywords: Run, Rules, Explorer, Method, KB, Rules Editor
References: None |
Problem Statement: What considerations should be made when modelling flexible pipes / hoses in the pipe segment block in Aspen HYSYS? | Solution: With regards to flexible pipes (in steady state), these can be thought about as pipes with many bends. As the name suggests, the geometry of these pipes are not fixed, so the general advice would be to make a conservative estimate for the number of bends in such a system. As such, it is possible to overestimate the pressure loss in this system. You can modify the roughness (based on the pipe material) and should be independent of the flexible nature of the pipe. The same would hold for the thermal conductivity of this system.
In many systems, the flexible pipe will only account for a fraction of the length of the entire flow system, so engineering judgement has be made as to how accurate this modelling needs to be, compared to the system as a whole.
There is one further point to note - dynamic simulations incorporating flexible pipes should be carefully considered. In highly transient modes of operation, it should not be attempted model these rigorously in dynamics. it is possible that a flexible pipe can move/shift in large changes to flow (unlike rigid, fixed pipes). As such, some energy (derived from the momentum of the fluid) is extracted from the fluid in the system. In a real system, this will manifest itself as a pressure drop. This is not modelled / compensated for in Aspen HYSYS. However, if it is believed the flexible pipe to be stationary, then possibly, dynamic models can be used.
Keywords: flexible pipe, hose
References: None |
Problem Statement: What is the meaning of the 3 different curves for the temperature profile in crossflow plate fin exchanger | Solution: In crossflow plate fin exchangers, three lines are shown for each stream, corresponding to its temperature along the exchanger centerline and on the left- and right-hand sides.
For axial flow streams, the three lines each represent a flow path. For crossflow streams, the lines are transverse to the flow path and represent stream temperature contours across inlet and outlet (the two sides of the exchanger) and in mid-exchanger. One line will normally be flat, representing the uniform inlet temperature of a crossflow stream. The general philosophy is to supply the extreme points and middle points. The data tabulated and plotted relate to three sets of points along the exchanger length, along the extreme left and right sides, and along the middle of the exchanger. You could find more details in the Help menu - PlateFin: Numbering Grid Points.
Keywords: Plate fin exchanger
Temperature profile
Crossflow streams
References: None |
Problem Statement: How can I map a Class View to different Classes? | Solution: It is possible to map a Class View to different Classes through separate Composite Views.
To do so, follow the next steps:
1) Right-click on the Class Views folder and insert a new Class View. Name it and click on ‘OK’.
2) Now right-click on the Composite Views folder and insert two Composite Views. For each, enter a name and select the appropriate Class, then click on ‘OK’.
3) Next, right-click on one of the Composite View’s window and select ‘Insert Top’ to add and attribute. Name the Composite View Attribute and select the data type, for example ‘Real’, and select the quantity type, for example ‘Temperature’. Add as many attributes as needed.
4) On the Class View window, add a Class View Attribute by right-clicking on a blank space and select ‘Insert Top’. Name the attribute, select both data type and category, for example ‘Equipment’.
5) Once you have created the number of Class View Attributes needed (which in most cases are equal to the number of attributes per Composite View), left-click on a Composite View Attribute, drag and drop it onto a Class View Attribute. After that, select ‘Synchronize All’. The Composite View Attribute will be mapped to the Class View Attribute. The same may be done with other Composite Views attributes.
This is how a ClassView is mapped to different Classes.
Keywords: Composite Views, Class Views, Class, Attributes, Class Library Editor, CLE.
References: None |
Problem Statement: What is the criteria for ACCE to select motor type for Pump? | Solution: If you specify (or the system calculates) a driver power greater than 300 HP (224 KW) with a motor type, a Totally Enclosed Water Cooled (TEWAC) motor will be generated. In APEA and ACCE, the additional piping lines for cooling water and an additional temperature control loop are generated.
In case 1 below since the driver power is 37.5 KW, a TEFC motor is generated.
In case 2 below since the driver power is 425 KW (>224 KW), a TEWAC motor is generated.
Keywords: Motor type, pump motor
References: None |
Problem Statement: How do users generate a new component list with a different boiling point temperature range if they already have had an old component list? | Solution: If users want to generate the new component list with a different boiling point temperature range, please follow the steps below.
1. Import a new component list from the system pak (C:\Program Files (x86)\AspenTech\Aspen HYSYS VX.X (Software Version)\Paks). It includes many different Hypos for different temperature range.
2. Create a new fluid package with the new component list. Provide a new package name (for example : Basis 2)
3. Select the new Basis2 for the assay and recharacterize the assay if you have the assay in your assay management database
4. Change the fluid package in the simulation and reattach the assay. You will see an updated component list.
Keywords: Change the component list, Assay, Temperature Range
References: None |
Problem Statement: How to move records from one folder to another folder using Aspen SQLplus | Solution: SET EXPAND_REPEAT=1;
FOR SELECT record_name AS moveit FROM sourcefolder WHERE record_name LIKE 'xxx' DO
INSERT INTO destinationfolder(record_name) VALUES (moveit);
DELETE FROM sourcefolder WHERE record_name LIKE moveit;
END;
Query notes: ·
The SET EXPAND_REPEAT=1 command expands the folder repeat area to create space for the INSERT INTO statement. ·
The SELECT statement selects the records, based upon their name. In this case 'xxx' is moved. ·
The INSERT INTO command inserts the record(s) into the destination folder. ·
The DELETE command deletes the record from the source folder. ·
The END statement closes the FOR loop.
Keywords: None
References: None |
Problem Statement: Does AspenTech support Aspen InfoPlus.21 in a 'Cluster' environment? | Solution: In V8.5 Aspentech introduced Aspen MES Clustering which is aSolution to minimize downtime and promote higher availability of supported servers in Aspen’s MES product family, specifically its process information server Aspen InfoPlus.21 and Aspen Production Record Manager. TheSolution is based on proven, widely used, and mature technology built into Microsoft’s server operating systems, known as Failover Clustering.
For more information on Aspen MES Clustering refer to the Aspen MES Cluster Administration Guide.
Prior to V8.5 Aspen InfoPlus.21 was not developed to take advantage of the failover or loading features provided by Microsoft Clusters. Furthermore, AspenTech did not test or officially support Aspen InfoPlus.21 within a cluster environment.
Keywords:
References: None |
Problem Statement: Is it possible to predict foaming in an Aspen HYSYS Column? | Solution: Aspen HYSYS does not have the capability to predict foaming in a column.
Starting with V9.0, the Column Analysis feature was included in the software. This feature allows the user to use the foaming factor as a user input.
This factor will affect the liquid height and it is used just to calculate pressure drop. By default, a value of 1.0 is used as System Foaming Factor. This factor is located under Geometry | Design Parameters | Design Factors per tray. The default value implies that you are working with a typical non-foaming system. Lower values indicate more foaming.
Please review the topic Foaming Calculations under Help menu (press F1) in Aspen HYSYS to review the recommended foaming values.
Keywords: Foaming, Foamers, Factor, Tray, Column, Geometry.
References: None |
Problem Statement: No indirect costs Calculated Despite User-Specified Indirects as a Percentage of Direct costs, in the Indirects and Proratables Form | Solution: Users have a few options for providing projects indirect costs. One way to do this is by entering indirect costs in the Indirects and Proratables form (Basis for Capital Cost/Customer External Files/Indirects - Proratables). For example, to calculate material taxes as a percentage of direct material costs, navigate to the Indirects and Proratables form and provide the Input as follows:
1) Code of Accounts -
Keywords: ACCE, Economic Evaluation, indirects and Proratables, Materials and Taxes, suppress defaults, M, N
References: documentation provides a list of all system Code of Accounts and their definitions. The Code of Account for Material Taxes is 62
2) If entering the Indirects as a factor of a system calculated direct cost then first select the Percent of Category in the Percent Basis sub category. SUMM is the option for total direct materials cost.
3) Finally, provide the percentage value in the appropriate field, according to the Percent Category selected,within the Percent Basis. For instance, if the Percent of Category selected is Material based, then provide a Percent of Direct Material and not labor.
The snapshot below illustrates that project material taxes are equivalent to 4% of total direct material costs and the output will be reported in the Code of Account 62 (“Materials Taxes”) field:
However, if this indirect costs is not shown in the project calculated costs it might be because of the option selected for system generated equipment bulks in the General Project Data form. Make sure that you have not specified M in the General Project Data form, Suppress default equipment/area/project bulks field. Doing so will result in no cost being generated for any indirects defined as a percentage of a system generated cost/. I.e no costs will be generated for COA 62. If the intention is to suppress system generated equipment bulks but still have user indirects calculated, leave the Suppress default equipment... field blank default input), or specify option N:
Alternatively, specify Indirect costs, in the Indirect and Proratables form, as an absolute cost on a Total cost basis |
Problem Statement: The AspenTech Calculator Engine service is not required for Aspen Calc clients. | Solution: The AspenTech Calculator Engine service, which executes scheduled calculations, is now optional.
A Service sub-feature of the Aspen Calc product in the AMS installation controls whether the service is installed. This sub-feature is selected by default for Server installs and not selected by default for Standard installs. If the Service option is selected, the installation needs a user name and password to run the service. If the Service option is not selected, the installation doesn''t require a user name or password. Without the service, calculations can still be created and scheduled on the client machine but the scheduled calculations only execute when the user is logged in.
Keywords: aspen calc
calc
AspenTech Calculator Engine
References: None |
Problem Statement: What is the difference between the two Auto Section options for Column Internals Analysis? | Solution: Using Column Internals Auto Section in Aspen HYSYS and Aspen Plus users can automatically creates column sections based on feed and draw locations or internal flow rates.
When Auto Section | Based on Feed/Draw Locations is selected, the program uses the following logic to auto section the column:
1. HYSYS/Plus starts Section 1 from the top tray.
2. The Stage Number is increased by 1 until a Feed, Product, Pump Around Draw, or Pump Around Return is encountered.
Note if a Feed or Pump Around Return is encountered at Stage I, HYSYS ends Section 1 at Stage I-1 and starts Section 2 at Stage I.
Note if a Product or Pump Around Draw is encountered at Stage I, HYSYS ends Section 1 at Stage I and starts Section 2 at Stage I+1.
HYSYS repeats the same logic until the bottom tray is reached. If there is no reboiler, this is the Nth stage. Otherwise, it is the (N - 1)th stage.
If you select Auto Section | Based on Flows, HYSYS uses the following logic to auto section the column:
1. HYSYS starts Section 1 from the top tray. If there is no condenser, it starts with Stage 1. Otherwise, it starts with Stage 2.
The Stage Number is increased by 1.
2.If the liquid flow from Stage I differs from the flow of stage I-1 by more than 20%, a new section is started at Stage I.
HYSYS repeats the same logic until the bottom tray is reached.
Keywords: Column Internals Auto Section, Based on Feed/Draw Locations,Based on Flows
References: None |
Problem Statement: How can a flowsheet be optimizated using sequential modular mode? | Solution: Attached is an example of a user kinetic subroutine for an RCSTR.
This file will run in V7.3 and higher.
The simulation includes two RCSTR reactors. One uses the standard Power Law expression. The other uses a User kinetic routine of the Power Law expression. A Fortran compiler is needed to compile and run the subroutine.
Reaction
Acetone + Allyl Alcohol -> N-Propyl Propionate
r = K*EXP(-E/RT)*CA*CB**0.5
Where
CA = Concentration of Allyl-Alcohol, in kmol/m3
CB = Concentration of Acetone, in kmol/m3
Pre-Exponential Factor = 52860000 m3**0.5/kmol**0.5-Sec
Activation Energy = 62E6 J/kmol
Keywords: None
References: None |
Problem Statement: How can I modify the inlet piping non-recoverable pressure drop limit percentage? | Solution: Every time that users come across a situation in which the inlet piping non-recoverable pressure drop exceeds the specified percentage value of the set pressure for a pressure relief valve (which is set to 3% by default), a warning message related to the inlet piping non-recoverable pressure drop will appear. (See the KBSolution 137594 'How can I stop having warnings in the “Inlet piping non recoverable pressure drop”?' for more details).
The inlet piping non-recoverable pressure drop limit percentage can be modified as follows:
A) For V8.8 and older versions on Home | Run | Options.
B) For V9.0 and newer versions on Home | Run | Calculation Settings.
The Options / Calculation Settings Editor will be displayed. On the bottom-right corner of the editor, you will find the ‘Warn at: X %’ field. By default, this warning will be displayed if the pressure drop in the inlet piping to a relief valve exceeds 3% (recommended by API), but it may be modified at user’s will. If the ‘Gauge’ check box is selected, the percentage will be calculated using gauge pressure.
Keywords: Inlet Piping Non-Recoverable Pressure Drop, Inlet Piping, Pressure Drop, Limit, Percentage, Warning.
References: None |
Problem Statement: How to create a Trend using the Data Trending function. | Solution: 1. From the main menu tab click to open the Capital Cost icon. (highlighted in the image below)
2. Select the Interactive Reports report type
3.Open the Trend options.
If starting a new Trend, select Clear All Saved Trends menu option. A confirmation dialog box will appear, Click Yes to confirm clearing of the data.
Select Add Trend Data to Database to add the scenario data to the trend database.
4.Select Create New Trend in Excel.
The Export Trend Data into Excel dialog box will open with the choice of either appending the trend data to the existing file or creating a new file. Select as appropriate.
Then a dialog box will open with capital cost categories of data to be created in the Excel. Select as required. This will create a new Excel Report.
5. Select to View Existing Trend Data which will open the Excel report.
Once an Excel report has been created, subsequent trends will be added to the same Excel report unless the option to Clear all Saved Trends is selected.
Scenarios can be added from the Aspen Icarus reporter of any of the 3 EEE suite products (ACCE, APEA and AIPCE).
To add a different scenario to the Excel report, open the scenario izp and follow the steps described above.
Please note that for the scenario(s) compared to be uniquely identified in the Trend report, ensure that the project title is entered via the General Project Data window (Project Basis View| General Project Data).
Data Trending excel report will identify each scenario based on the name entered as Project Title
Keywords: Trend Data, Trend, Aspen Icarus Reporter.
References: None |
Problem Statement: How to resolve the problem that ASW is not updating when a variable is changed in Aspen Plus? | Solution: A user has to follow several steps to synchronize the ASW and the Aspen Plus:
When a table was created via the Organizer at the ASW, the user has to close the Aspen Plus software. Only Microsoft Excel is kept working.
To change variables at the Aspen Plus the user has to click Visible to open the Aspen Plus model at the Excel ribbon or inside the Organizer.
3. Change the variables at the Aspen Plus, click Run. The values at the ASW will be refreshed automatically.
Keywords: ASW, Aspen Plus, updating variable, variable, refresh variable
References: None |
Problem Statement: aspenONE Process Explorer allows manual data entry to the Aspen InfoPlus.21 database for authorized users. It can be enabled in the Add/Remove Legend Columns dialog by toggling the option for Manual Entry from OFF to ON. However, after changing the value for a tag and pressing Submit, the following message may be displayed:
'Servername says: Failed call to check AFW'
and the new value will not be written to Aspen InfoPlus.21 (IP.21) database.
This KB article provides steps to resolve the above-mentioned error. | Solution: · Open Internet Information Services (IIS) Manager and click the expansion button next to the nodename
· Select Application Pools
· Right-click Aspen Security Pool and select Advanced Settings option from the Context menu
· Scroll down to Identity under Process Model and click the “…” button to invoke the account settings dialog
· Select the Custom Account radio button and enter the same domain account that is being used by the Aspen InfoPlus.21 Task Service service
· Save your changes and restart the IIS Admin Service or run iisreset from the Command Prompt (using Run As Administrator option)
Keywords:
References: None |
Problem Statement: What is a Snapshot Manager in Aspen HYSYS Dynamics? | Solution: During dynamics modeling, the Snapshot Manager can be used to create a snapshot of the simulation. Select Take a Snapshot to create a snapshot file that contains the state of the simulation at that instance of time when the integrator is still running. The snapshot files saved as a .hsp file allow users to trace back to a specific point in the simulation and review the results calculated at that time.
This tool is very useful for Operation Training System (OTS) applications, where the user can routinely save the state of the simulation at various times to study and compare the results from the snapshot files.
Keywords: Snapshot Manager, hsp file, OTS
References: None |
Problem Statement: Is there a way to copy source data from one scenario to another in Aspen Flare System Analyzer? | Solution: To copy source data from one scenario to another in Aspen Flare System Analyzer, you can use the 'Copy To' option.
Following steps will give provide more details.
1. Open the source editor (Control Valve or Relief Valve) and select the 'Copy To' button on the bottom of the window.
2. Select the Scenario to which you would like to copy the data to.
In the screenshot below, the PSV01 data from default scenario is copied to Scenario1.
Please note that 'Copy To' option will copy data only once.
Keywords: Source, Copy To, Scenario
References: None |
Problem Statement: What is the unit for liquid holdup in a pipe? | Solution: Liquid holdup in a pipe is defined as the ratio of the volume occupied by liquid in a segment to the total volume of the segment, at a given point in the pipe. It is thus a fraction which varies from 0 (for all gas flow) to 1 (for all liquid flow).
Keywords: Liquid holdup, pipe
References: None |
Problem Statement: What is the difference between HTFS and TEMA vibration analysis? | Solution: Exchanger Design & Rating performs vibration analysis for Shell & Tube exchangers. There are two options available, HTFS and TEMA methods.
HTFS vibration model is more elaborated than TEMA method. The latter basically considers 5 major tube spans having a fixed vibration boundary condition with no simultaneous effects of spans on each other. In addition, TEMA method cannot consider the details of supports effects on vibration.
Another example would be how the HTFS method can difference between the effects of a rigid and a normal blanking baffle in the vibration analysis, while the TEMA method cannot handle this.
In general, it is always recommended to use HTFS vibration method over TEMA. Default option within EDR is to use HTFS only:
Keywords: Vibration analysis, HTFS, TEMA.
References: None |
Problem Statement: How is the fluidiation height (the transport Disengagement Height) modeled in the fluid bed? | Solution: The fluidized bed model is divided into different vertical zones. At the bottom there is the dense fluidized bed also called the bottom zone, above which the freeboard or upper dilute zone is located.
The transient region in between is denoted as the splash zone, where rising bubbles from the bottom bed explode and cause a more fuzzy transition between the bottom bed and upper dilute zone.
From this region, the solids hold-up gradually decays until it becomes constant or at least nearly constant. The distance between this point, where the solids concentration becomes nearly constant, and the surface of the fluidized bed, is called the 'Transport Disengagement Height' (TDH).
Several correlations for the determination of the transport disengagement height are given in the literature. In the present model of the fluidized bed the correlations shown below are available for its determination.
Chan and Knowlton (1)
George and Grace (2)
db is the diameter of a bubble at the surface of the bottom zone
Fournol el al. (3)
g is the standard acceleration of gravity
Fung and Hamdullahpur (4)
db is the diameter of a bubble at the surface of the bottom zone
Note: The gas velocity u used in the correlations above is the superficial gas velocity at the top of the fluidized bed
Besides the determination of transport disengagement height (TDH) by use of one of the correlations above, it is also possible to determine the TDH based on the calculated solids volume concentration profile of the fluidized bed. The present model of the fluidized bed determines the TDH by use of both approaches. As already mentioned above the solids hold-up gradually decays with height until it becomes nearly constant. In the present model the solids volume concentration is treated as constant if the gradient dcV/dh is smaller than a given tolerance (tolcv).
The TDH is than given as the distance between the height H* at which the solids volume concentration becomes constant and the height HB of the bottom zone.
In the present model of the fluidized bed, the calculated value of the transport disengagement height has no influence on the calculation result itself. The calculated TDH will be shown on the results tab. If the calculated height of the freeboard is smaller than the transport disengagement height a warning is raised.
I.H. Chan, T.M. Knowlton: The effect of pressure on entrainemt from bubbling gas fludized bes, in D. Kunii and R. Toei (eds.) Fluidization, Engineering Foundation, New York 1984, pp. 283-290
S.E. George, J.R. Grace: Entrainment of particles from aggregative fluidized beds, AIChE Symp. Series, 74 (1978), pp. 67-73.
A.B. Fournol, M.A. Bergougnou, C.G.J. Baker: Solids entrainment in a large gas fluidized bed, Canadian Journal of Chem. Eng. , 51 (1973), pp. 401-404.
A.S. Fung, F. Hamdullahpur: Effect of bubble coalescense on entrainment in gas fluidized beds, Powder Technology, 77 (1993), pp. 251-265.
Keywords: Fluid Bed, fluidization height, transport disengagement height (TDH), references
References: None |
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