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Problem Statement: Aspen Shell & Tube exchanger V7.3.1 does not solve in Aspen HYSYS V7.3 with Input error 1124 The data input for E-Shell inlet nozzle loc.
It happens with E-shell and D-shell case files built prior to EDR V7.3 integrated in HYSYS. When you load the old HYSYS models in HYSYS V7.3 you will see the message Input error 1124 The data input for E-Shell inlet nozzle loc. if there is any inconsistency between the inlet nozzle location and the distance between tubesheet. | Solution: For an E shell, to set the flow to be counter or co-current, then from Input | Exchanger Geometry | Shell/Heads/Flanges/Tubesheets | Shell/Heads tab the E shell flow direction (inlet nozzle location) is used to set the location of the inlet nozzle. If it is set to;
Near rear head then the flow direction of the first tube pass will be in opposite direction (countenter-current flow) to the shellside flow
Near front head, then the first tube pass and shellside flow will be in the same direction (co-current flow)
From Input | Exchanger Geometry | Nozzles | Shell Side Nozzles tab, the distance to front tubesheet can be set for both the inlet and outlet nozzles. For Shell&Tube V7.3 and older, use of this item would result in the Setting Plan, viewed from Results | Mechanical Summary Setting Plan & Tubesheet Layout, displaying the location of the nozzle as set. Sometimes this input item was used incorrectly in attempting to set co or counter current flow.
Starting from EDR V7.3.1, additional data checking was applied to prevent this, which results in the Input Error 1124, it the location of the nozzles set is in conflict with the E shell flow direction. To eliminate the error, delete the distance to the front tubesheet for the nozzles or simple set Default E shell flow direction (inlet nozzle location) under Input | Exchanger Geometry | Shell/Heads/Flanges/Tubesheets | Shell/Heads tab.
To show the problem We have attached both EDR files. If you run EDR within HYSYS V7.3 it is not possible to change this setting so you have to manually open the EDR file and make changes. However in HYSYS V8.0 and later you can open the full EDR Browser and make changes by clicking on Model Details.
Keywords: Error 1124, nozzle location, E-shell, D-shell
References: None |
Problem Statement: This knowledge base article describes how to access Microsoft's FileSystemObject object model through Aspen SQLplus COM objects. The FileSystemObject object model contains properties, methods and events which allow manipulation of drives, folders and individual files. Before the FileSystemObject model was available in Aspen SQLplus, such operations had to be carried out with the Aspen SQLplus SYSTEM command.
An additional explanation of FileSystemObject object model can be found in Microsoft's on-line web documentation:
http://msdn2.microsoft.com/en-us/library/z9ty6h50.aspx | Solution: The following example code works for version 4.0.1 and later, but must be used for versions prior to v2004. In addition, when the following code is used, the user must add a reference to the following two objects within the Aspen SQLplus Query Writer (View |
Keywords: COM
object
manipulate
access
read
timestamp
properties
References: s.)
OLE Automation (for the _NewEnum class)
Microsoft Scripting Runtime (for the FileSystemObject class)
Code Example for versions prior to v2004:
local oFSO FileSystemObject;
local oFldr Folder;
local oFile;
local i int;
local fc IEnumVARIANT;
oFSO = createobject('Scripting.FileSystemObject');
oFldr = oFSO.GetFolder('c:\');
fc = oFldr.Files._NewEnum;
for i = 1 to oFldr.Files.count do
fc.next(1, oFile, null);
WRITE oFile.Name;
WRITE '-- Path: ' || oFile.Path;
WRITE '-- Parent Folder: ' || oFile.ParentFolder;
WRITE '-- File Type: ' || oFile.Type;
WRITE '-- Size: ' || oFile.Size || ' bytes';
WRITE '-- Created: ' || oFile.Datecreated;
WRITE '-- Last Modified: ' || oFile.DateLastModified;
WRITE '-- Last Accessed: ' || oFile.DateLastAccessed;
end
Native support for the FileSystemObject has been added to Aspen SQLplus v2004. Therefore, the query can be simplified substantially. The following query will work with Aspen SQLplus v2004 and later. Note: Since native support for the FileSystemObject has been added to v2004, it is no longer necessary to add references to OLE Automation and Microsoft Scripting Runtime objects.
Code example for v2004 and later:
LOCAL oFSO;
LOCAL oFldr;
LOCAL oFile;
oFSO = createobject('Scripting.FileSystemObject');
oFldr = oFSO.GetFolder('C:\');
FOR EACH oFile IN oFldr.Files DO
WRITE oFile.Name || oFile.Datecreated;
END |
Problem Statement: How can I write an SQL query to scan through trend values to detect and report a change? | Solution: Sample query provided.
-- select ip_trend_value, ip_trend_time from testpv;
StartTime = TIMESTAMP'2005-02-23 14:11:56';
EndTime = CURRENT_TIMESTAMP;
ChangeFrom = 0;
ChangeTo = 100;
write 'Start Time: ' || StartTime;
write 'End Time: ' || EndTime;
LastTime = StartTime;
LastValue = -9999;
while LastTime is not null do
CurrentTime = (select min(ip_trend_time)
from testpv
where ip_trend_time > LastTime
and ip_trend_time < EndTime );
if CurrentTime is not null then
CurrentValue = (select ip_trend_value
from testpv
where ip_trend_time = CurrentTime);
if (CurrentValue = ChangeTo) and (LastValue = ChangeFrom) then
write 'CurrentValue: ' || CurrentTime || ' ' || CurrentValue;
end;
end;
LastTime = CurrentTime;
LastValue = CurrentValue;
end;
exception
write 'Something went wrong.';
end;
Keywords: None
References: None |
Problem Statement: In Aspen Exchanger Design & Rating (EDR), user can see tube length actual and tube length effective under Results | Mechanical Summary | Exchanger Geometry | Tubes tab. This is calculated on the basis of user's input for the type and size of the front & rear Tubesheets and tube projections from front & rear Tubesheets.
How is the Area Ratio calculated when running the design case? | Solution: For Tubesheets, you can specify the require tubesheet type and desired thickness under Input | Exchanger Geometry | Shell/Heads/Flanges/Tubesheets | Tubesheets tab. Program will then evaluate the effective tube length = Actual Tube length - Tubesheet Thickness (front & rear) - Tube projections (from front & rear tubesheet). You can view the effective tube length under Results | Mechanical Summary | Exchanger Geometry | Tubes tab.
In Aspen Exchanger Design & Rating, you can specify the minimum % excess surface required under Input | Program Options | Design Options | Optimization Options tab and when you run the design case program will try and find the optimum design with the specified area ratio. When you see the optimization path; you can see that area ratio is equal to Actual Tube length divided by required tube length.
In case of U type rear head, user can choose whether or not to include the effective U bend area for heat transfer under Input | Program Options | Thermal Analysis | Heat Transfer tab. If 'No' is chosen for this option, program will evaluate the thermal analysis using the total effective area equal to
, where'd' is outside tube diameter, 'L' is tube length effective and 'n' is total number of tubes.
If 'Yes' is chosen for this option, total effective area will be Area calculated above plus U bend area as calculated under Results | Mechanical Summary | Exchanger Geometry | Bundle tab.
Keywords:
References: None |
Problem Statement: Unhandled exception error when executing an INSERT statement on remote table in a relational database. | Solution: The problem is that the databases.dat file is missing from the %SETCIM%\sql folder.
Make sure this file exists and that the SETCIM environment variable is pointing to the correct path.
(drive:\Program Files\AspenTech\InfoPlus.21\db21)
From version 2004 (7.0) and later, there is a better error message:
Failed to open file %SETCIM%\sql\databases.dat
Keywords:
References: None |
Problem Statement: How do I change the disk space for the temporary files? | Solution: You can change the disk space by going to Tools | Preferences | Advanced tab
Keywords: space, crash, disk, temporary, files
References: None |
Problem Statement: Do you have a list of input and result variables for the EDR programs? | Solution: All input and result variables can be seen in the EDR (Exchanger Design and Rating) User Interface by visiting the form and going to View>>Variable List (see below)
However you will not be able to copy multiple variables from this variable list window.
If you want to see the variable list in a spread sheet format you need to access the BjacApp.mdb access database file. This file is in the \\DAT\MDB folder of all installations (for example C:\Program Files\AspenTech\Aspen Exchanger Design and Rating V7.1\Dat\Mdb).
Keywords: variable list, bjac, edr, code, program, VB
References: None |
Problem Statement: Horizontal thermosyphon reboilers normally consist of a G or H shell, where boiling of the process fluid takes place on the shellside, with the heating usually being supplied by process stream although any convenient hot product (vapour or liquid) may be used.
G and H shells have a longitudinal baffle on the shellside, that is usually solid but could be made from a perforated plate. The baffle must not come very close to the section ends as this will increase the pressure drop through the unit due to the turn round losses.
Within Aspen Shell & Tube Exchanger, the window length at the front or rear head of a G or H shell can be specified in the Input | Exchanger Geometry | Baffles/Supports | Longitudinal Baffle tab, where this | Solution: describes how the default values used by the program are determined.Solution
The longitudinal baffle must not come very close to the section ends as this will increase the pressure drop through the unit. It is common to ensure that the total turn round cross flow areas are at least equal to;
outlet nozzle area
parallel flow area
longitudinal baffle length to be two-thirds of the tube length
Within Shell & Tube, the default values for the window lengths are determined from;
Window length = Minimum of either 0.4 * shell diameter or 0.2 * tube length
Keywords:
References: None |
Problem Statement: Within Aspen Shell and Tube Exchanger, different Simulation calculations can be performed, where based upon the geometry supplied for the exchanger, the following parameters can be determined;
Outlet temperature (and quality) - default
Inlet temperature (and quality)
Flow rate
In each case, the two parameters not being calculated, such as the inlet temperature and mass flowrate, in the case of the outlet temperature case are taken to be fixed.
This | Solution: explains how the different Simulation options can be set and when they might be used.Solution
From Input | Problem Definitions | Application Options the Calculation mode can be set to Simulation, where the Simulation calculation input for both the Hot and Cold Side are then active.
The conventional Simulation calculates the Outlet temperature for a specified flow and inlet conditions, and this is usually the default.
Simulations calculations to determine inlet temperature are in general less stable and calculations in which the inlet temperature is being found for both streams can be inherently unstable.
Flow rate calculation may be appropriate when the hot fluid is condensing steam and the inlet condition (dew point) and outlet condition (just below the bubble point) are fixed. The flow rate will be adjusted to match the heat load required by the other stream.
The Simulation option can be set independently for the hot and cold streams, for example the hot stream may be finding the flow, and the cold stream may be finding the outlet temperature.
For all simulation calculations, initial starting values are needed for all three parameters for each stream. These values are entered in Input | Problem Definition | Process Data, together with an estimated heat load if necessary. It is recommended that you explicitly supply the two parameters you wish to fix, so there is no uncertainty as to what these values are.
Please note that the ?Adjust if over specified? input does not determine the type of simulation calculation. This item is used if 4 parameters have been specified (i.e., heat load, flowrate and inlet/outlet temperature) that are inconsistent and then you can specify which item the program can adjust.
Keywords: Calculation method, Inlet and outlet temperature, Flow Rate
References: None |
Problem Statement: What is the logic for the default bonnet dimensions determination? | Solution: The front head (bonnet) dimensions default to (can be changed in Shell & Tube Mechanical):
-Cylinder length = 40% of shell diameter
-Plus elliptical head depth (shell diameter/4) plus head straight length
The nozzle elevation defaults to:
-Minimum nozzle cylinder length (function of nozzle diameter)
Shell & Tube mechanical uses the same defaults than EDR thermal program except that the mechanical program includes the actual calculated thicknesses for the head, body and nozzle flanges.
There is an option to exclude the bonnet (front head) cylinder when not needed, as in the case of axial nozzle flows
Keywords: Bonnet size
References: None |
Problem Statement: How does Aspen Shell & Tube Exchanger treat the number of baffles specified in a I, J and G shell types? | Solution: For I, J and G shells, it is assumed that there is always a central baffle. The number required is the total number of baffles in both shell side passes including this central baffle.
If you specify an odd number of baffles, for example 19 baffles, then 1 is central baffles and 18 are regular baffles with 9 baffles on each shell side pass is used. If you specify an even number for baffles, for example 20, then the program assume 10 baffles on each shell side pass and 1 central baffle. It reports only the regular baffle count as the total baffles.
Keywords: Baffles, I/J shell, G- shell.
References: None |
Problem Statement: The ?ASME? material database being used in EDR programs may not be the latest version, or the version that the user prefers. The material list and/or material properties between different annually published versions could be slightly different.
Below describes how to find out which version of the ASME material database is used, and how to change. | Solution: To set the ASME material database, from the top of the program menu go to Tools | Program Settings | Files tab. At the bottom of the form, you can see ?ASME material database? that can be set from the drop-down list.
After selecting the ASME material database, click ?OK?. Now the corresponding ASME material database will be used within the program.
Each year, ASME publishes an up-to-date database of all current ASME materials. In each update, a percentage of them will be modified in some way or new ones added (Material list and properties can be accessed by going to Tools | Data Maintenance | Material Database (for ASME use metals) tab, as described inSolution 110796).
Generally an exchanger is designed against the latest edition of the code. That edition would be used through the life of that exchanger, hence the need to keep older versions of the database available for the user to select.
Keywords: ASME material database, update, databank, annual publish.
References: None |
Problem Statement: In which baffle cut orientation does a triangle face upward or sideways with 30 degree triangular tube pattern? | Solution: A triangle top in a 30 degree triangular tube pattern faces up when the baffle cut is horizontal. It faces sideways when the baffle cut is vertical. The triangle top faces the shell the side flow. Shell side fluid flows up and down when baffle cut is horizontal. It flows sideways when the baffle cut is vertical.
Figure: 30 degree top-facing triangle pattern for horizontal baffle cut.
Figure: 30 degree side-facing triangle pattern for vertical baffle cut.
Keywords: Triangle, up, sideway, horizontal baffle cut, vertical baffle cut, orientation
References: None |
Problem Statement: When we specify two or more exchangers in series, which one of the below configuration is correct? | Solution: Configuration in Figure 1 is correct. It means that the heat exchangers are not identical in terms of the shellside flow to the tubeside pass history.
To Check this you can look to the temperature profile. Go to Result | Calculation Details | Analysis along Tubes | Plot tab. For example in below case, hot stream inlet nozzle location is near the fixed head and leaving / entering again near rear head. (follow the red line) and finally leave the exchanger near the fixed head.
Keywords: Series, Geometry, Configuration
References: None |
Problem Statement: For the same exchanger in Checking/Rating mode, one may see different clean area ratio after entering non-zero fouling factors. What causes the clean area ratio to be different? | Solution: When the program is run with fouling factors, the clean area ratio is derived by scaling the dirty area ratio, assuming that the fouling is removed, and the shellside and tubeside mean coefficients remain the same. The mean coefficients are calculated using the temperatures on the fouling surfaces.
When the program is run with no fouling, the clean and dirty area ratios are the same by definition. In this case, the heat transfer coefficients are calculated based on tube wall temperatures which can be different from the fouling case. This causes the difference in the area ratio for clean case.
If an accurate area ratio for clean is needed, run the exchanger without fouling factors (set to zero).
Keywords:
References: None |
Problem Statement: How many nozzles are allowed to be used for each heat exchanger shell? | Solution: The number of nozzles depend on the geometry of the exchanger and of the shell selected. The shell configuration is based on TEMA standards so they cannot be modified to have non-conventional configurations.
The following table summarizes the number of nozzles that each shell can allow:
Shell type
Inlet nozzles
Outlet nozzles
Intermediate nozzles
E
1
1
0 - 1
F
1
1
0 - 1
G
1
1
-
H
2
2
-
I
2
1
0 - 1
J
2
2
0 - 2
K
1 - 10
1 - 10
0 - 10
X
1 - 10
1 - 10
0 - 10
It is important to note that if a number different than the ones showed in the above table is introduced, the program will display an input warning such as the following:
Due to this, the software is only taking into account expected number of nozzles, and not the number of nozzles that was introduced by the user.
Keywords: Nozzle
Number of nozzles
Shell configuration
Heat exchanger geometry
References: None |
Problem Statement: A Button named ''Enable numerical conversion'' can be found above the main window diagram of all the Aspen EDR applications. What is this button used for? | Solution: This button is designed for users' convenience when they want to change the units of some parameters WITHOUT converting the numerical values.
The button is set as being pushed (slightly grey compared to the diagram background) already by default. This means the numerical conversion is enabled. If a user changes the unit of a parameter, the numerical values will be converted as well. For example, for a temperature of 46 degree C in the program, with this button pushed or pressed, the numerical conversion is enabled. If users switch the unit to degree F, the temperature will be converted to 114.8 degree F.
However, if the button is released (restore the same colour as the rest of the diagram), this means the numerical conversion is not enabled. When users switch to other units, the numerical values of the parameters will be kept constant.
This feature is especially useful when users mistakenly input a series of parameters with the wrong unit. By releasing the button, they can switch to the correct unit without converting the numerical values.
Keywords: Enable numerical conversion, switch unit, under wrong unit setting.
References: None |
Problem Statement: How can I specify number of tubes plugged in each pass? | Solution: In V7.1 and earlier versions, Aspen Shell & Tube exchanger used to allow the user to specify total number of tube plugged and in calculations each pass is assumed to have symmetrical number of tubes plugged. But, starting with V7.2, User can specify the number of tubes plugged in each pass individually. Following instructions illustrate on how to specify the number of tubes plugged in each pass.
1. Go to Input | Exchanger Geometry | Bundle Layout | Layout Parameters | and select Specify Pass Details for Tube Layout Option, please see the picture below.
2. Next move onto Input | Exchanger Geometry | Bundle Layout | Pass Details TAB and specify the number of tubes plugged for each pass. Please see the picture below.
Keywords: Plug, Number of plugged tubes, Pass Details.
References: None |
Problem Statement: In some circumstances, when generating the physical property data using the Aspen Properties databank, and entering the components directly into Aspen Exchanger Design and Rating (EDR) you may notice that the enthalpy reported is zero at a number of temperature points. When the case is run this generates a fatal error.
If this occurs then it maybe that you are trying to generate properties below which the flash calculations are performed. Below is given a method on how you can extend the temperature range for the physical properties. | Solution: Instead of using the Property Methods tab form the Input | Property Data | Hot/Cold Stream Compositions, the Advanced Options tab should be used instead to read an external Aspen Properties (APRPDF) file that contains information on the components, the property methods and temperature ranges for the flash calculations.
The method to produce the file is as follows;
1. Create an Aspen Plus file, setting the property methods and component
2. In Setup | Simulation Option | Flash Convergence tab, set the lower limit temperature to a value less than the current 10K default
3. From the main menu, select File and Export an ?aprpdf? file
4. Bring this aprpdf file into EDR, where the component and property methods will be read in. When generating property data, points should now be generated at lower temperatures, depending upon the lower limit set
Further information on the valid temperature and pressure ranges for the various Property Methods can be found from the following link on the Aspen Support website: http://support.aspentech.com/webteamasp/My/FrameDef.asp?/webteamasp/AllDocsDB.asp
From here select ?Process Engineering Products? then ?Aspen Properties? and download from
Keywords:
References: ?Aspen Physical Property System V7.x Physical Properties Methods? pdf. |
Problem Statement: What is the maximum amount of property information that can be imported from Aspen HYSYS into Tasc+? | Solution: It is currently possible to import up to twelve data points when bringing process and property information from Aspen HYSYS into Tasc+ due to the data structure limitation in Aspen TASC (i.e. the precursor to Aspen Tasc+). Although Aspen Tasc+ can accept up to twenty-four input data points, the import feature does not yet support this functionality.
Note that the PSF screen will allow you enter more than twelve data points, however any property information beyond the first twelve points will not be imported.
Keywords: Tasc+, data, process, 12, 24, points, PSF, import, HYSYS, properties
References: None |
Problem Statement: What tube rows are checked for the HTFS vibration analysis when double segmental baffles have been specified? Which of the two overlap sections are taken into account? | Solution: As can be consulted onSolution ID 125368, the tube location taken into account for the vibration analysis is named as follows:
# 1 - Top Tube Row in Bundle
# 2 - First Tube Row Outside Baffle Overlap
# 3 - Top Tube Row Inside Baffle Overlap
# 4 - First Tube Row Inside Baffle Overlap
# 5 - Bottom Tube Row in Bundle
When double segmental baffles are used, these locations are placed as shown on the image below. For now, the vibration analysis is currently restricted to four tubes.
As noticed in the figure, double segmental baffles have two overlap regions, where each part of the split baffle overlaps the central baffle.
Each region is identical to a reasonable approximation. So only one tube in the overlap region is examined (Tube location # 4).
As to regards of locations # 2 and # 4, a row near the baffle cut is being used since this will have a slightly higher mass flux than rows nearer the centre.
Keywords: Baffle
Double-segmental
Vibration
Tube location
References: None |
Problem Statement: When there is no history data available, a SELECT statement which selects from the history repeat area will return No rows selected. For example, all the query statements below will return No rows selected if there is no history data available.
SELECT name, ip_description, ip_trend_time, ip_trend_value FROM tagname;
SELECT name, ip_description, ip_trend_time, ip_trend_value FROM tagname.1;
SELECT name, ip_description, ip_trend_time, ip_trend_value FROM tagname.1;
This knowledge base article provides examples which show how to automatically return the fixed area data when there is no hisotry data available. | Solution: There are a few methods whic will enable the data from the fixed area to be automatically returned when no history data exists.
Method 1: With the help of a flow control construct.
IF (SELECT COUNT(ip_trend_value) FROM tagname) = 0 THEN
SELECT ip_description, '' ip_trend_time, '' ip_trend_value from tagname;
ELSE
SELECT ip_description, ip_trend_time, ip_trend_time FROM tagname;
END
Alternatively, rather than use the set function COUNT, you can check whether NULL is returned using other set functions.
LOCAL result;
result = (SELECT MAX(ip_trend_value) from tagname);
IF result = NULL THEN
SELECT ip_description, '' ip_trend_time, '' ip_trend_value from tagname;
ELSE
SELECT ip_description, ip_trend_time, ip_trend_time FROM tagname;
END
Method 2: The easiest way is to make use of table JOIN.
select a.ip_description, b.ip_trend_time, b.ip_trend_time from tagname a left join tagname b on a.name = b.name
Keywords: repeat area
fixedarea
historian
References: None |
Problem Statement: When querying a tag's values using SQLplus, asterisks are returned instead of the numeric values For example:
select ip_trend_value, ip_trend_time from ip_analogdef where name like 'xx.pv'
might return the following results:
ip_trend_value ip_trend_time
-------------- --------------------
************** 19-NOV-06 00:00:01.0
************** 19-NOV-06 00:00:56.0
************** 19-NOV-06 00:01:51.0
************** 19-NOV-06 00:02:46.0
************** 19-NOV-06 00:03:42.0
When looking at the tag in a Process Explorer plot, the values are displayed normally. | Solution: SQLplus only displays up to 6 digits to the left of the decimal. To work around this, use a specific format record when selecting the values. For example:
SELECT ip_trend_value USING 'F22.11' FROM ip_analogdef where name like 'xx.pv'
Or
Use the CAST function to cast the values as a char (character string) to display the larger values in their entirety.
Keywords: Asterisks
Sqlplus query
References: None |
Problem Statement: You cannot install an ACM Model .MSI file from a drive created using the DOS subst command.
The installer will fail with the message The installation was interrupted | Solution: Don't install from a drive created with DOS subst command. Copy the MSI file in another location.
This is a limitation with the Microsoft Windows Installer, not a deficiency in our software. Unfortunately the fact that it is Microsoft software at fault means that we cannot provide a more helpful error message.
Keywords:
References: None |
Problem Statement: This | Solution: s contains instructions on how to interrogate the wmi interface from SQLplus.
Solution
This example will lookup user information using Windows Management Instrumentation (WMI).
local strComputer, wql;
local objWMIService, Locator, Service;
local results, userData;
strComputer = '.';
Locator = CreateObject('WbemScripting.SWbemLocator');
objWMIService = Locator.ConnectServer ('.', 'root\cimv2');
objWMIService.Security_.ImpersonationLevel = 3;
wql = 'select * from win32_useraccount ' || 'where name=''becks'' and domain=''CORP''';
results = objWMIService.execquery(wql);
write results.count;
for each userData in results do
write userData.domain || '\' || userData.Name || ' Fullname: ' || userData.fullname;
write userData.description;
end
Keywords:
References: None |
Problem Statement: The objective is to calculate the maximum between an element of an array and a particular set value and then place the result in the corresponding element of a new array.
Basically something like:
xnew(1) = MAX(x(1),xset);
xnew(2) = MAX(x(2),xset);
xnew(3) = MAX(x(3),xset);
...
xnew(N) = MAX(x(N),xset);
If one types this in the model by using implicit arrays as in:
xnew = MAX(x,xset);
Every element of xnew takes the same value independantly of the value of x(i) and xset. WHy is this and how can the result be corrected? | Solution: MAX is a mathematical operator that returns a scalar from its arguments, i.e. in the case above where the code is written implicitly, there will be N equations generated for each element of xnew for which the value is calculated from the maximum between all elements of array x and the scalar xset. This will be:
xnew(i) = maximum ( (x(1) to x(N)) , xset)
So the way to write the code correctly is to write the arrays explicitly, which is something we always recommend to avoid ambiguity. Her eis an example of how we would write the appropriate code in the model:
Model testMAX
N as integerparameter (10);
xnew([1:N]) as realvariable;
x([1:N]) as realvariable(fixed);
xset as realvariable(5, fixed);
for i in [1:N] do
xnew(i) = MAX(x(i), xset);
endfor
End
Keywords:
References: None |
Problem Statement: How to run a query in AspenTech SQLplus to get data from a SQL database. | Solution: A SQL database can be queried using SQLplus.
The SQL database has to be set up as a datasource. This can be done by doing the following:
1. Go into Start/Settings/Control Panel/ODBC Data Sources.
2. On the ODBC Data Source Administration dialog box, select the System DSN tab. Click on Add.
3. Select either SQL Native Client or SQL Server from the list of choices.
4. Click on the Finish button. You are now at the SQLplus Set Up dialog box.
5. Give it a Name and Description, and select from the drop down menu the SQL server you want to connect to.
6. Click on Finish.
7. On the next screen, click on Test Data Source to confirm connectivity, if successful, click OK.
Once the ODBC datasource to the SQL server is created, you can add a link to that remote database in the query tool.
1. Click on the Tables icon.
2. Click Add Link.
3. In the Link Name box, type a name for your link. The link name cannot include a comma (,), and AspenTech recommends that you not include quotation marks ().
4. In the Data Source Name box, you can select an existing ODBC data source or enter a connection string.
5. In the User Name box, type the name of a user account for the database that you want to access.
Leave blank if you want to use Windows authentication.
6. In the Password box, type the password for the user account.
Leave blank if you're using Windows authentication.
Once the link is added, you can create a query by clicking on the link you created and select the database and table.
Clicking on the Paste Query button should give you a query for the table you selected.
For example, for a SQL server, Master database, DBO owner and SPT_monitor table,
the query would look something like this:
SELECT *
FROM
SQL_ODBC_Link.master.dbo.spt_monitor
Where SQL_ODBC_Link is the Data Source Name you created, master is the ODBC table qualifier, dbo is ODBC table owner and spt_monitor is the table name.
Keywords: SQL database server
References: None |
Problem Statement: Trying to use an .appdf created with an Aspen Plus run that includes a user kinetic subroutine, the following error messages are issued when loading the acmf in ACM
Properties >> ****TERMINAL ERROR
Properties >> COULD NOT OPEN DLOPT FILE:
Properties >> dlopt.opt
Properties >> ****TERMINAL ERROR
Properties >> ERROR DURING DYNAMIC LINK OF USER ROUTINE(S) OR IN-LINE FORTRAN
Properties >> PLEASE CHECK FILE cstrusr1.ld FOR LINKER MESSAGES.
Properties >> *** SEVERE ERROR
Properties >> COULD NOT RESOLVE USER OR IN-LINE FORTRAN SUBROUTINE(S):
Properties >> SUBROUTINE USRKST IS MISSING
Properties >> ****TERMINAL ERROR
Properties >> PROGRAM TERMINATED DUE TO UNRESOLVED ROUTINES | Solution: In fact the ACM run does not even use these routines. So the best action is to go back to Aspen Plus bkp, remove the user kinetic, and regenerate the appdf file.
The otherSolution is to copy manually the dll and the dlopt.opt file in ACM simulation working folder (e.g. AM_simulation_name).
A similar problem occurs if you have declared user properties for user property sets, or other subroutines that are dynamically linked by Aspen Plus.
Note also that object files (*.obj) are copied automatically by ACM, so anotherSolution is to not use a dll but the obj files (however, for this approach you must have the fortran compiler installed and configured correctly - e.g. you can run the simulation in Aspen Plus).
Keywords:
References: None |
Problem Statement: When an Aspen SQLplus query is run against a MS Microsoft Access database, the query locks the database, preventing other queries of MS Access from executing properly. Re-starting InfoPlus.21 successfully unlocks the MS Access database until another query of MS Access is run. | Solution: Aspen SQLplus includes an option on the SQLplus database link dialog box to Disconnect on any error. Setting this option will reconnect you to any database type on any error, not just errors that SQLplus recognizes as network failures.
To set the option:
1. Click the button on the toolbar in the SQLplus Query Writer.
2. Select the link, and then click Edit Link.
3. In the SQLplus database link dialog box, click the Disconnect on any error check box and click OK.
The DISCONNECT command can also be used at the end of the query to manually disconnect network links. The proper syntax for the command is as follows.
DISCONNECT link_name;
Keywords: access
disconnect
lock
References: None |
Problem Statement: Can you explain which changes are required in the code of a flowsheet VBscript to be used within a macro in Excel? | Solution: When you run a flowsheet script, any method you invoke is automatically applied to the flowsheet object (because the script is invoked within the flowsheet).
When you invoke a method in Excel, the same happens, but this time the default object is Excel, not ACM anymore.
This is why when you do this in a VBScript in Aspen Custom Modeler (ACM):
set v = Resolve(B1.x)
you will need to say this in Excel:
set v = acmObj.simulation.flowsheet.Resolve(B1.x)
(where acmObj is the ACM application object).
as you are now in the Excel context, and you need to explicitly state you want to talk to ACM's Resolve method. If you were trying set v = Resolve(B1.x), you tell Visual Basic that you want to invoke the Resolve method of Excel Worksheet object. Since this method does not exist, an error will occur.
To start ACM from a macro in Excel, you need to invoke the GetObject or CreateObject method. See ACM on-line help, Aspen Custom Modelere reference, Automation
Keywords:
References: section for details.
So, to convert the flowsheet script code to be used in Excel, you need to:
call GetObject/CreateObject to return the ACM application object
prefix each ACM method and property with the ACM application object |
Problem Statement: How to invoke library scripts? | Solution: To invoke a script that is in a library script's folder, use InvokeLibraryScript. This takes the name of the library as the first argument and the name of the script as the second argument, for example:
Flowsheet.B1.InvokeLibraryScript Custom Modeling, LibraryScript
If the library is given as an empty string (that is, ), all libraries are searched to find the named script.
(Note: the example given in the documentation incorrectly uses brackets.)
New in version 12.1 you can pass arguments to and receive arguments back from a library script. Arguments added after the library name and script name will be passed into the library script
e.g. Flowsheet.B1.InvokeLibraryScript Custom Modeling, LibraryScript,B1
The script LibraryScript will receive the string B1 in the variable input(1). Note that this functionality is not available in version 11.1. (Note also that it is not documented in version 12.1.)
Keywords:
References: None |
Problem Statement: Is it possible for a query to return the total number of data points in history for InfoPlus.21 tags? | Solution: One possible way to return the total number of data points for a tag is to COUNT the IP_TREND_TIME field of the repeat area for a tag. The other possibility is to return the maximum occurrence number (OCCNUM) in the repeat area of a tag.
In most cases, the values returned by MAX(OCCNUM) and COUNT(IP_TREND_VALUE) will be equal. However, the COUNT option generates more reliable results. The OCCNUM value may be incorrect if tags have been duplicated or if a new tag was created using a record ID (RECID) previously used by another tag.
Sample Scripts
NOTE: The tag name, atcai, comes from the demo database.
Sample 1
WRITE 'COUNT1: ' || (Select COUNT(*) from atcai.1);
Sample 2
WRITE 'COUNT2: ' || (select COUNT(ip_trend_time) from atcai);
Sample 3
WRITE 'OCCNUM: ' || (Select MAX(OCCNUM) from atcai.1);
Sample Results
COUNT1: 16360
COUNT2: 16360
OCCNUM: 16360
The Count syntax will also take a Where clause:
SELECT COUNT(IP_TREND_VALUE) FROM ATCAI WHERE IP_TREND_VALUE > 13;
SELECT COUNT(IP_TREND_VALUE) FROM ATCAI WHERE IP_TREND_TIME BETWEEN '06-SEP-07 08:00' AND '06-SEP-07 09:00'
Keywords: history
occurrence
occurrences
data
count
points
total
References: None |
Problem Statement: How can I copy the specification or value from one block to another? | Solution: One option is to use a script and the RegExp vbscript object. Let's say for example you want to copy the specifications of B1 into the specifications of B2, you can use this:
on error resume next
for each v in B1.FindMatchingVariables(~)
if not v.IsParameter then
txt = v.name
set re = new RegExp
re.Pattern = ^B1\.
txt = re.Replace(txt, B2.)
if txt <> v.name then
v2 = resolve(txt)
if err.number <> 0 then
err.clear
else
v2.spec = v.spec
end if
end if
end if
next
The pattern ^B1\. means anything that starts with B1..
More information about regular expressions in VBScript can be found on Microsoft web site:
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/script56/html/reconIntroductionToRegularExpressions.asp
Keywords: regular expression
search
replace
advanced
substitute
match
remap
References: None |
Problem Statement: When I invoke a script such as:
Example - script called report:
set report = CreateObject(...)
.
.
this error message appears:
Error in script report at line 11, position 1: Cannot assign to Report
What does this mean and how to avoid the error? | Solution: The problem is that the script is also called report. So when you try to access the variable report the script actually accesses the script object report.
In fact any object with the same name as a VBScript variable will cause this problem, including block names, tasks, tables and plots.
To prevent the conflict, you need to declare the variables in the script with the private keyword.
Example, script with private Statement
private report
set report = CreateObject(...)
.
.
It is always good practice to declare all variables you use in VBScript as private to prevent such conflicts.
Keywords:
References: None |
Problem Statement: When creating an SQLplus database link to an Oracle database, the following error occurs:
However a System DSN has already been created to the Oracle database using Oracle ODBC and the connection was already tested as successful. Furthermore, using Microsoft Excel to perform a database query using the DSN is successful (the successful connection also indicates that the tnsname to the Oracle database has been configured on the machine.) | Solution: This is usually caused by the System Environment Variables not being set properly. To check on the System Environment Variables,
1. Right-click on My Computer.
2. Select Properties from context menu.
3. Click on the Advanced tab.
4. Click on the Environment Variables button.
5. Look for the variable called PATH under the System variables section.
What are the things to look up for?
1. Check to see whether there is a system variable called ORACLE_HOME and make sure that the variable value is set to the directory where Oracle software is installed. E.g. C:\oracle\ora92
2. Check on the PATH variable and make sure that the variable value includes %ORACLE_HOME%\bin if ORACLE_HOME is defined or the Oracle software installation bin directory (E.g. C:\oracle\ora92\bin) if ORACLE_HOME is not defined.
3. Check for broken PATH variable values. For example, a missing semi-colon as in below.
PATH=.C:\oracle\ora92\bin (WRONG)
PATH=.;C:\oracle\ora92\bin (CORRECT)
4. Make sure the Authenticated Users group has Read & Execute permission to the ORACLE_HOME installation. For example, in the case of Oracle 9i client installation, look for ora92, right-click and select Properties. Select the Security tab and select Authenticated Users group. The Authenticated Users group should have the following permission checked.
- Read & Execute
- List Folder Contents
- Read
If the above permissions are already checked, unchecked Read & Execute permission and re-checked it again.
If all of the above had been done and still fail to connect successfully, try a reboot of the machine to check whether it helps.
Keywords: database link
oracle
References: None |
Problem Statement: This sample program shows how to create a simple .NET Windows application that uses the .NET OdbcDataAdapter object to read data from InfoPlus.21 using SQLplus. | Solution: Follow the steps below to create the application. The code is also attached to the knowledge base article.
Launch Microsoft Visual Studio .NET
Select File | New | Project
Select a Project type of Visual C# Projects
Select the Windows Application Template
Type a Project Name and click OK
An empty Windows Form will be displayed.
From the ToolBox, drag a DataGrid object onto the form. Resize the Grid object.
Double-click the Form to access the code
9. In the public Form1() block, add the following code:
public Form1()
{
// Required for Windows Form Designer support
InitializeComponent();
// Create the ODBCAdapter Object
// Substitute the IP21 portion of the string to the data source name configured on your system
System.Data.Odbc.OdbcDataAdapter oAdapter = new
System.Data.Odbc.OdbcDataAdapter(
Select name, description from IP_Analogdef, // Query to Execute
dsn=IP21); // Specify the name of the ODBC data source which uses the AspenTech SQLplus driver
// Substitute the IP21 portion of the string to the data source name configured on your system
System.Data.DataSet oDs = new System.Data.DataSet();
oAdapter.Fill(oDs);
dataGrid1.DataSource = oDs.Tables[0];
}
Run the application. It will execute the query and display the results in the grid.
Keywords:
References: None |
Problem Statement: This knowledge base article describes how to save query results to a csv file or Excel sheet. | Solution: The following query will create a file called OutTest.csv which contains a single sheet called 'OutTest'. Files of type '.csv' can be opened with Excel. The resulting file will be created on the InfoPlus.21 server, not the client PC that is running SQLplus.
The results of the subsequent select statement will be written to the first two columns of the csv file.
SET OUTPUT 'C:\OutTest.csv';
SET COLUMN_HEADERS = 0;
SELECT NAME || ',' || ip_description FROM ip_analogdef;
Note: Because the COLUMN_HEADERS option is set to zero, column headers of the result set will not be written to the csv file. Remove this line or set COLUMN_HEADERS to 1 to write the column headers to the csv file.
Keywords:
References: None |
Problem Statement: This knowledge base article describes how to send e-mail with multiple lines of text in the body of the e-mail using an Aspen SQLplus query. | Solution: Be aware that in order for the code to work, it will be necessary to obtain and install an application that is able to send e-mail messages from the command line (such as IndigoMail available from the following website http://www.indigostar.com/indigomail.php ). In addition, make sure to include a reference to the CDO object by selecting Microsoft CDO for Windows 2000 Library from within Aspen SQLplus | View|
Keywords: email
emails
References: s menu.
local msg;
local message;
message = 'Hi There';
message = message + chr(13);
message = message + chr(13);
message = message + 'How is the weather there?' + chr(13);
message = message + 'Let me know if you get this message.' + chr(13);
message = message + chr(13);
message = message + 'Regards,' + chr(13);
message = message + 'Big Smile' + chr(13);
Write message;
msg = CreateObject('CDO.Message');
msg.From = '[email protected]';
msg.To = '[email protected]';
msg.Subject = ' Message from Aspen SQLplus test';
msg.TextBody = message;
msg.Configuration.load(cdoDefaults, '');
msg.Send; |
Problem Statement: How is the standard deviation computed for a histogram plotted in Aspen Real-Time SPC for Process Explorer? | Solution: Standard deviation for a histogram chart is calculated using the sample mean. The main assumption here is that the data selected for the given time range is a sample of the population. The sample standard deviation is an estimate based on a set of numbers.
The formula for calculating the estimated standard deviation is:
Where i=1 to n, xi is each individual point, x ̅ is the sample mean, and n is the sample size. n-1 indicates the degree of freedom.
This method assumes that the sample data selected for the histogram represents the population.
Keywords: Standard Deviation
Histogram
SPC
References: None |
Problem Statement: This knowledge base article describes how to use InfoPlus.21 record-level security to restrict the availability of SQLplus web reports to users based on the user's InfoPlus.21 access level. | Solution: The SQLplus reports do not contain functionality to restrict access to the reports based on user roles. The public reports are available for all users and the private reports are only available to the users who created them. However, for every SQLplus web report which gets created, there is a corresponding record created in the InfoPlus.21 database under the SqlReportDef record definition. If your site uses record-level security, one workaround would be to create public reports then have the system administrator set the read privilege accordingly for the SqlReportDef records based on the security roles. If a user does not have read access to the SqlReportDef record, then the user should not be able to access the corresponding SQLplus web report with the same name.
Keywords:
References: None |
Problem Statement: Why do I not see a RhoV2 violation warning for Shell side Inlet nozzle when I have RhoV2 value more than the TEMA standard limit? | Solution: In Aspen Shell & Tube Exchanger program, users can check the RhoV2 analysis in Results |Thermal / Hydraulic Summary | Flow Analysis tab where the RhoV2 values are reported for the shell Inlet nozzle, shell entrance, bundle entrance, bundle exit, shell exit and shell outlet nozzle. You can find the corresponding limits for these various locations in the 'Recommended Good Practice' Section 10-17 of the TEMA handbook, 9th Edition.
You can check for RhoV2 violations from either Results |Thermal / Hydraulic Summary | Performance Tab or Results | Result Summary | Overall Summary tab.
For the shell side inlet nozzle, the RhoV2 values is used as a guideline to indicate if an impingement plate is required. Shell&Tube Exchanger will not give a RhoV2 violation warning message for the shell inlet nozzle if impingement plate protection is being used.
Overall Summary sheet will always display the actual calculated value for shell side inlet nozzle RhoV2, but the warning message is dependent on whether an impingement plate is selected or not.
Keywords:
References: None |
Problem Statement: I want to use Turbo-BIII, a kind of Wolverine tube. Where can I input data in Shell & Tube Exchanger? | Solution: You can input data for Turbo-BIII as follows:
1. Select Tube type: Internal enhancement
2. Select ?Wolverine Turbo: Any? as the tube internal enhancement
3. Select a tube outside diameter and nominal wall thickness from the document, http://www.wlv.com/documentation/TurboBIII.pdf.
4. The required surface area, coefficient and exponent data can also be obtained from: http://www.wlv.com/documentation/TurboBIII.pdf.
Keywords: Turbo BIII, Wolverine Turbo, tube internal enhancement
References: None |
Problem Statement: When I run a case with a X shell under Rating/Checking, the cumulative heat load is not displayed in the Calculation Details results, as shown in the image below: | Solution: The cumulative heat load, as displayed in the Stream details, is really only well defined for serial pass axial flow exchangers, which have a :;D calculation grid. With X-shells with 2:D grids, the definition becomes dependent on the grid size and on its definition. In the Standard method all intensive parameters are defined at grid points, but cumulative (extensive) parameters are evaluated over cells. All parameters for stream details are intensive, except for heat load, which is complicated in that it is an integral of extensive parameters.
The Advanced method was designed to overcome limitations of the Standard method and is the default calculation method in v7.2.
To select this calculation method, go to Problem Definition/Application options:
After selecting this, the Cumulative Heat load is calculated:
Keywords: Heat load
X shell
Advanced method
References: None |
Problem Statement: Low area ratio is observed in V7.3.2 for multiple shells in series with U-bends. Is there a work-around? | Solution: The problem occurs observed in V7.3.2 only with advanced method and when
(1) there are Multiple shells and
(2) heat transfer in U-bend is switched off and/or
(3) blanking baffle is specified.
Work-around 1: Use standard method forSolution.
Work-around 2: If you want to use advanced method, turn on heat transfer in U-bend and do not specify blanking baffle.
Keywords: Low area ratio, low heat transfer coefficient.
References: None |
Problem Statement: How to troubleshoot ACM exported model (MSI) file installation? | Solution: If you are having problems installing a .MSI file, you can create a log by executing the following command in a DOS box:
msiexec /Id:\MyModel.msi /Lvoicewarmup! d:\info.log ALLUSERS=1
Substitute d:\MyModel.msi with the name of your MSI file, as well as the location of the log file as appropriate.
You can then sent the info.log file to us to help diagnosing problems.
Keywords:
References: None |
Problem Statement: This knowledge base article provides an example of how to call a procedure or a function from another procedure or function. This script also demonstrates how to call a function using input parameters. | Solution: -- Beginning of Script
--User kicks off script by calling procedure UseGBF.
--Procedure UseGBF then calls fcn GoodBadFlag (and passes the time
--parameters to GoodBadFlag).
--GoodBadFlag does a tag select then returns the value of the
--select to the calling procedure.
--The calling procedure then displays the result to the user.
FUNCTION GoodBadFlag (StartTime timestamp, EndTime timestamp)
-- When this function is called, the following line will return the
-- result of this select statement to the calling procedure.
Return (select cast(IP_TREND_VALUE as char) from d-IP_analog.1
where IP_TREND_TIME between StartTime and Endtime);
--Note: A function was used here so the query will work via ODBC.
--The SQLplus ODBC driver will only treat functions as having return
--values.
-- Close out the function with an END statement
END
PROCEDURE UseGBF
local FromGBF;
-- Now call the function GoodBadFlag to get the value... then use
--it in this procedure however you wish
FromGBF = GoodBadFlag ('01-dec-04 00:00:00','06-dec-04 15:30:00');
Write 'The value of ' || FromGBF || ' was passed into this procedure';
-- Or if you don't want to declare a local var in this procedure...
Write 'You can do this too: ' || GoodBadFlag ('01-dec-04 00:00:00','06-dec-04 15:30:00');
END
-- UseGBF; is the calling statement which initiates the action.
-- The call to UseGBF is outside of both the procedure and function.
UseGBF;
--End of script
Keywords:
References: None |
Problem Statement: A customer wanted to analyze history for various tags with the goal of outputting a sequential report that would list the start and end time a tag stayed in a particular state (like good or bad.) How is this problem solved using SQLplus?
How to list Start and End time for a sequential period with the same status | Solution: The sample code will output Start and End time for a sequential period with the same status
Change StartTime to the oldest time you need to include
Change machine state.1 to the correct record name
Keywords: None
References: None |
Problem Statement: A runtime parser error can occur when calling a proceduredef record which contains a cross BY query. The following error message is seen:
Column or Variable %%%% is not found.
Below is an example from a customer when using a for loop with a select query:
for (select ts, max(value) by name from history where
ts between tm1 and tm2 and period = 24:00:00 and name in
('tag1','tag2','tag3','tag4','tag5') group by ts order by ts) do | Solution: The problem is that the parameter is not evaluated at the time that the procedure is parsed, so the cross by query has no data and so no columns. You can get around this by explicitly selecting columns from the cross by query. See below:
for (select ts, 'tag1','tag2','tag3','tag4','tag5' from
(select ts, max(value) by name from history where
ts between tm1 and tm2 and period = 24:00:00 and name in
('tag1','tag2','tag3','tag4','tag5') group by ts) order by ts) do
Keywords:
References: None |
Problem Statement: It is possible to add Aspen InfoPlus.21 (IP.21) as a Linked Server in Microsoft SQL Server using the Aspen SQLplus ODBC driver. For information on how to set this up as a linked server refer to | Solution: 116533. If security is enabled on the InfoPlus.21 database, the SQL tool initiating the connection can receive an Access Denied error message.
To prevent Access Denied errors, which account should be granted permission?Solution
Linked Server connections are made via the account that starts the MSSQLSERVER service. This account starting the MSSQLSERVER service must be granted permission to the Aspen InfoPlus.21 database if security is implemented.
If the MSSQLSERVER service starts up under the Local System account, this must be changed to a specific domain user account that have permissions to access the Aspen InfoPlus.21 database.
Keywords: Linked Server
Access Denied
References: None |
Problem Statement: The Aspen eBRS product (AeBRS) uses a Relational database in which the Timestamp values are stored in a UTC (or GMT) format rather than as local timezone timestamps.
The client tools provided as part of AeBRS have been developed so that they internally convert the UTC timestamps so that they then display them as Local times.
However if a non AeBRS tool, such as Aspen SQLplus, is used, it would not know that these times needed conversion to see them as Local Timezone Timestamps.
How can we structure Aspen SQLplus to convert the AeBRS UTC timestamps into Local Timezone times, taking into account the crossing of Daylight savings time changes as well as the options of East or West of GMT? | Solution: After communications with AspenTech Support, Jerry Sandoval of Dow Chemical developed such an Sqlplus function, and gave AspenTech permission to publish this in his name as follows:
-- Function: UTC_To_Local_Time
-- Description: Adjust UTC format Timestamp to Local Timezone Timestamp.
-- Automatically accounts for local timezone and Daylight Savings Time.
-- Inputs: 1 Parameter - Timestamp in UTC Format
-- Outputs: Updated Passed-in Parameter adjusted to Local Time Format
--
-- Modification History:
--
-- Jerry Sandoval Dow Chemical V01.00 August 12, 2005 Original
--
FUNCTION UTC_To_Local_Time(PASSED_TIMESTAMP OUT TIMESTAMP)
Local Hrs_i INT,
Mins_i INT,
Offset_i INT,
Sign_c CHAR;
--
-- Return without change if TIMESTAMP is NULL.
--
IF PASSED_TIMESTAMP IS NULL THEN RETURN;
END;
--
-- Determine Timezone Offset in Minutes from UTC Time.
--
Hrs_i = SUBSTRING(local_iso8601(PASSED_TIMESTAMP) FROM 28 FOR 2);
Mins_i = SUBSTRING(local_iso8601(PASSED_TIMESTAMP) FROM 31 FOR 2);
Offset_i = (Hrs_i*60)+Mins_i;
--
-- Determine if Timezone Offset is plus or minus.
--
Sign_c = SUBSTRING(local_iso8601(PASSED_TIMESTAMP) FROM 27 FOR 1);
IF Sign_c = '-'
THEN Offset_i = Offset_i * -1;
END;
--
-- Return Adjusted Passed in Timestamp (in tenths of seconds).
--
RETURN PASSED_TIMESTAMP+(Offset_i*10*60);
END;
Keywords:
References: None |
Problem Statement: When double-segmental baffles are used in Aspen Shell & Tube Exchanger program, users can specify baffle cut inputs on Input | Exchanger Geometry | Baffles/Supports | Baffles tab. Corresponding outputs (actual, nominal in diameter, actual in area) are reported on Results | Mechanical Summary | Exchanger Geometry | Baffles tab.
How does Aspen Shell & Tube Exchanger program define the ''baffle cut'' for double-segmental baffles in terms of both diameter and area, when users specify inputs and read outputs? | Solution: The ''inner baffle cut'' of double-segmental baffles in the Shell&Tube Exchanger program is measured from the shell central line to either side of edges of the two pieces of outer baffles. The ''outer baffle cut'' of double-segmental baffles is measured from either side of the edges of the inner baffle piece.
With Double Segmental there are two forms of baffle:
1) A two-piece baffle with an Inner Baffle Cut X (Note: This is measured from the exchanger centerline). Inner Baffle Cut (%) = X/Ds x 100
2) A one-piece baffle with an Outer Baffle Cut Y. Outer Baffle Cut (%) = Y/Ds x 100
The corresponding inputs in Shell&Tube can be found on Input | Exchanger Geometry | Bundle/Supports | Baffles tab.
These ''baffle cut'' inputs are in terms of certain percentages of diameter of the baffle OD (outer diameter).
The corresponding outputs can be found on Results | Mechanical Summary | Exchanger Geometry | Baffles tab. The inputs specified by users will be reported as ''Nominal (% diameter)''. The program may adjust these baffle cut inputs slightly to place the baffle cut edge between the centre line of two tube rows or length alignments.
The ''Actual (% area)'' are the baffle cuts in terms of certain percentages of flow areas. Users need to be aware that, like the diameter cuts, the area cut values reported here are referring to only one of the two identical inner/outer cut areas. This is why when switching from a single-segmental baffle into a double-segmental baffle setting with the same outer cut (for single-segmental it is just ''cut''), users won't see the outer area cut being doubled, because it refers to one piece of the two cut areas.
Keywords: Double-segmental baffle cut, Cut in diameter, Cut in area, Inner cut, Outer cut
References: None |
Problem Statement: The baffle spacing or pitch is the distance between centers of adjacent baffles. The value can be entered into Aspen Shell & Tube Exchanger for the spacing (center-center) under Input | Exchanger Geometry | Geometry Summary | Geometry tab or Input | Exchanger Geometry | Baffles/Supports | Baffles tab.
When the Shell & Tube Exchanger is run, an input warning 1121 may be given, where this | Solution: describes how the upper and lower baffle spacing limits are determined.Solution
The minimum baffle spacing is given as in TEMA RCB-4.51 which is 2 inches.
The maximum baffle spacing is arbitrarily set to the shell inner diameter.
It should be noted that the maximum baffle spacing is not determined by TEMA RCB-4.52 for the maximum unsupported spans length. However, the unsupported span lengths are checked by the program where an Operations Warning 1661 is reported if the value is exceeded.
Keywords:
References: None |
Problem Statement: When running the aspen shell and tube program I receive the following error message: The data input for Cold liq/vap-only out noz is unacceptable | Solution: This error refers to the shell side's outlet nozzle specifications.
Aspen Shell and Tube Exchanger requires a kettle to have separate nozzles for liquid and vapor outlet.
The error is displayed if you choose no for Use separate outlet nozzles for cold side liquid/vapor flows. (Input || Exchanger Geometry || Nozzles || Shell Side Nozzles )
Even if you don't have liquid product you have to choose yes or set default.
If you don't have a liquid product, choose yes and don't provide any dimension under liquid product. If there are default numbers, take them off. Only provide the vapor outlet nozzle dimensions in this case.
If you need the vapor and liquid come through the same nozzle, you would probably need to model a thermosyphon instead of a kettle reboiler. (seeSolution 121745)
Keywords: kettle reboiler
nozzle
outlet
References: None |
Problem Statement: It is possible to have different duties in each half of an I or J shell due to the temperature profiles? | Solution: In Aspen Exchanger Design & Rating (EDR),you can run the simulation case in Advanced Calculation mode under Input | Problem definition | Application Options so that program performs rigorous calculations based upon the geometry.
For an I or J shell, the shell side inlet fluid is split so that for an I shell, the shellside fluid enters at each end of the exchanger and flow towards the middle to an central outlet nozzle. For a J shell, there is only one central inlet nozzle and the flow splits into two flowing towards the outlet nozzles located at the ends of the shell.
This arrangement can cause different thermal performance in each half of the exchanger, where the greater the number of tubeside passes would minimize the difference.
Having one shell side inlet nozzles at the top could establish different flow patterns in each half of the exchanger where the shell side flows combine and exit through the outlet nozzle. One half of the exchanger will have counter-current flow and the other half will predominantly have co current flow pattern, which results in the difference in heat transfer duty for the two halves of the exchanger. However, as you put in more tube passes, you expect to have similar duties in each half of the exchanger.
You can view the different temperature profiles or vapor fraction under Results | Calculation Details | Analysis along Shell | Plot tab to see the plot of bulk temperature/vapor fraction with respect to Distance from End where there may be a difference at the outlet nozzle. The screen shot below shows a typical 'I' Shell type case where shell side fluid enters through two nozzles located at either end of the shell and the condensed liquid leaves through one nozzle located at the centre of the shell. The left half of the curve indicates that the shellside bulk temperature is dropping quicker and to a lower exit temperature than the right half of the exchanger.
If you run the model in Standard Mode, you will see a symmetrical temperature profile analysis as both the halves of the exchanger have the same duty.
Keywords: divided flow, J21
References: None |
Problem Statement: Can I specify the size, layout, and number of rows of impingement rods in Aspen Shell & Tube Heat Exchanger program? | Solution: Yes from V7.2 version user can specify the size, layout, and number of rows of impingement rods, and they appear on the Tube Layout diagram.Impingement rod layout options include matching the underlying bundle layout or layout angles of 30, 45, or 90 relative to the inlet nozzle.
Keywords: impingement rods, impingement etc;
References: None |
Problem Statement: What are the definitions for tube length and number of tubes for a U-tube exchanger? | Solution: For a U-tube exchanger, the tube length and number of tubes are defined as follows.
Tube Length: This is the length of the straight section of the tube from the end at (or projecting beyond) the tube plate to the beginning of the U-bend where the tube begins to bend.
Number of Tubes: Total number of holes in the tube sheet i.e. twice the number of actual U-tubes.
Keywords: U-tube, Length, Tube Count, Number of tubes.
References: None |
Problem Statement: In Aspen Shell & Tube Exchanger you may see the message ?Operations Warning 1671: The ratio of actual temperature difference to the temperature difference for pure counterflow is less than 0.75. It is not usually advisable to design or attempt to operate shell and tube heat exchangers at this condition.? What does this mean and why does it arise. | Solution: The above message is referring to the rule of thumb which suggests that you should not design a shell and tube heat exchanger where the Log Mean Temperature Difference (LMTD) correction factor (Ft) is less than 0.75. Although Shell & Tube Exchanger does not use the LMTD, a low Ft correction factor does have a physical meaning and operational implications. From Results | Thermal / Hydraulic Summary | Heat Transfer | MTD & Flux tab, Shell & Tube calculates the Overall Effective MTD and the One pass counterflow MTD, where the ratio of these can be compared to the Ft correction factor.
The Figure below shows the Ft correction factor plotted against the thermal effectiveness (P) for various ratios of the stream temperature changes (R). Please note the graph is not derived from real values, but is diagrammatic in order to demonstrate the problem. Users should consult curves given in the Tubular Exchanger Manufacturers Association, TEMA handbook or similar books.
Consider the case where the value of P is 0.7 and the value of R is 0.1. This gives a Ft correction factor of about 0.95, but more importantly the slope of the R curve at that point is not steep. Thus a change in the value of P (caused by process inlet temperature changes) will not cause a large change in the Ft correction factor.
Now consider a value of P of 0.95 and a value of R of 0.1. This time the Ft correction factor is about 0.6 or so. Again, more importantly the slope of the R curve at that point is very steep. Thus any change in the value of P (caused by process inlet temperature changes) will potentially cause a large change in the Ft correction factor. This means that the exchanger performance is very susceptible to changes in the process inlet temperatures.
Usually this warning arises with multiple pass units where there is a temperature overlap (i.e., the cold stream outlet temperature is above the hot stream outlet temperature. There are two possibleSolutions to this problem (assuming the process temperatures cannot be changed):
1. Use only one pass with countercurrent flow.
2. Use more than one shell in series (Shell & Tube Exchanger can handle up to 12 shells in series)
Keywords: Ft correction factor, LMTD
References: None |
Problem Statement: From the Exchanger Design and Rating (EDR) programs, from the Results | Calculation Details | Analysis along Tubes | Interval Analysis tab, the local temperatures are shown along the length of the exchanger. One column is labelled as the metal temperature, where the | Solution: lists the definitions of this column.Solution
In Shell and Tube the tube metal temperature is at the mid point of the tube wall.
In Air Cooled Exchanger the metal temperature is at the inner wall.
Keywords: Interval Analysis, Metal Temperature
References: None |
Problem Statement: ??OUI?O>I??cAOEIO??a?oAspen EDR?I?o????????E?#?EEDRI??e>oIA??#?>a??>i?i?o????OU'E>u??EI?AEDR????!#
?OO???O?>?A'E??a?U?>????#?OoI??i?o?????A?????>O>??EC??C?Eu/EyIeE?O??A????!#?a?EE?O?>????e??Start|Program Files|AspenTech, EO???O??IeO??A??????E??I?oI??e#???E??I?oO??o#??EDRIA??IIEe?I?o?c??Ai#?>o????File|OpenEY?O??O?'o???AIA??!# | Solution: O??A?aEDR?i?Y??E??AA???#?Au?eO?
-'o??Windows Explorer
-??Tools|Folder options|File Types
-?!O?EDRI??e#???>?Advanced
-??>?Edit, E>?o??>?Browse
-OU'E??Io'??UIA#??O??EDR?I?o?A????IA????#?O?O?O??O?OAuIeO??A????#?
-?!O?bjacwin.exe (??Oa#?ECO-IA??#????>EC???'>o???i?Y??E?)
-??>?OK, OK, OUOK
IOOU#??a?oO????AEDR?????IECOUAuEEDRIA??E?#?I?I?A?EIO?A''o??IA???AEDR????AE!#
Keywords: ?i?Y??E?#?????#?EEDRIA??I???
References: None |
Problem Statement: Why Aspen Shell & Tube Exchanger predicts different duty and temperature than Aspen HYSYS? | Solution: Aspen HYSYS solves a heat exchanger in simulation mode. If the calculation mode in Aspen Shell & Tube Exchanger is not simulation, then you may observer different duty and temperature. For example, you are running Aspen Shell & Tube Exchanger in rating mode and have 10% excess area. Aspen HYSYS will run the same model in simulation mode. That means Aspen HYSYS will utilize the whole heat transfer area of the exchanger and thus it will have higher duty.
Keywords: Duty, temperature, heat exchanger, shell & tube, EDR
References: None |
Problem Statement: There are times where after specifying an exchanger configuration, or my number of tubes, or the nozzle diameter, this information is not reflected on my TEMA sheet and EDR does not seem to be taking this into account. | Solution: Go to Input | Exchanger Geometry | Geometry summary and verify that you do not have the option Use existing layout under the Tube layout section.
When this is selected, the program will only take into account the geometry that has already been calculated and will not update with the new geometry that you specify.
Therefore, this option needs to be changed to New (optimum) layout.
Keywords: Geometry
Tube layout
Nozzle, tube count, number of tubes
Update
References: None |
Problem Statement: Why is the font color of the few properties white and the background color is dark red? | Solution: The white color font or burgundy - dark red color background serves as a warning. If a user input or overwritten property value is out of usual range then this warning is issued. For example, if the vapor specific value is higher than 1.2 BTU/(lb*F), then this warning is issued. If the values are correct then ignore the warning.
Keywords: property, background, red, burgundy, font, white
References: None |
Problem Statement: TEMA sheet line 6 is inconsistent with line 42 for a shell ID.
For example, a shell ID of 7.981 inch is reported as 7 inch in line 6 and 7.981 inch in line 42. | Solution: TEMA sheet line 6 by definition is a unit label displaying the shell ID. This value is typically a whole number (not exact) in inches. Thus an 8-5/8 inch OD unit with 102 tube length will be 8-102 if the ID is > 8.0 and 7-102 if the actual ID is < 8.0.
The value on line 42 is typically the actual ID used in the shell side heat transfer calculation thus this value will be exact.
For this case in US units: line 6 will be 7, line 42 will be 7.981.
For this case in SI units: line 6 will be 177.8, line 42 will be 202.72 mm.
Please refer TEMA standards for additional information.
Keywords: TEMA sheet, line 6, shell ID, whole number.
References: None |
Problem Statement: When generating the properties of a stream in EDR products, how to accurately model the solubility of Non-Condensable components such as CO2, CO, N2, H2S, Methane, HCN, NH3, H2 etc. in liquid phase. | Solution: Using Aspen Properties as property package and activity coefficient model such as NRTL or UNIQUAC as property method in EDR products one can generate the stream properties accurately. Aspen properties will perform VLE or VLLE calculations in the background based on the binary interaction parameters for each component pair and generate the properties.
But, in some instances the accuracy of VLE or VLLE calculations, especially when Non-condensable components or super critical components such as CO2, CO, N2, H2S, Methane, HCN, NH3, H2 etc. are present, then the solubility of these components in liquid phase solvents such as Water, Methanol, Ethanol, NH3, Benzene etc can be improved by defining these components Non-Condensable or super critical components as Henry's components. Henry's law is a special model for predicting the solubility of super critical components in Water and other organic solvents such as Ethanol, Methanol and Benzene.
To define these components as Henry's components, please follow the steps below.
1. Open your EDR file
2. Select Aspen Properties as property method
3. Add all components in the streams
4. Then select NRTL or UNIQUAC as property method on Property Methods TAB
5. Go to Stream Composition | Advanced Options | click the Button Aspen Properties Browser
6. Then go to Aspen Properties User Interface and on the Main Menu go to Data | Properties
7. Click Drop Down button for Henry's components and select 'New' and leave the default HC-1 and click OK.
8. Then click the Next button (button with ) until you go to Henry's components. Select these non-condensable components as Henry's components and click Next button and finish the setup.
9. Save this Aspen Properties file and save another copy in a known location and close the Aspen properties browser.
10. Now go to EDR program and stream properties page and Generate the properties.
Check under phase composition for concentrations of these components in Liquid phase.
If the above method fails to generate the properties as expected, then the alternative is to go to the Stream Composition | Advanced Options select the 2nd option and reference the saved copy of Aspen properties file and specify the composition and generate the properties.
Note: ThisSolution applicable only to Activity Coefficient models and pressures up to 10bar. Equation of state models such as Peng-Robinson, SRK, RK-Soave does not use the concept of Henry's law and they are vapor phase models.
Keywords: Henry's Components, Solubility, Concentration, Non- Condensables
References: None |
Problem Statement: After successfully running an EDR case, the user will be directly navigated by default to the ''Warning & Message'' tab. Users may prefer different forms, such as ''Optimization Path'' ''TEMA Sheet'' etc, depending on their specific engineering objectives of using the program.
Described below is how to specify which results form will be shown immediately after a run. | Solution: To set the first Results form displayed after run, from the top of the program menu, go to Tools | Program Settings | UI Options 2 tab, where you will see for each application there is a drop-down list allowing users to select which result form they want to view first after running a case. These forms for Shell&Tube for example, include:
? Warning & Messages
Optimization Path
Recap of Designs
TEMA Sheet
Overall Summary
Performance
Setting Plan & Tubesheet Layout
Analysis along Shell
Analysis along Tubes
Analysis for X and K shell
You can choose the one that you want to view immediately after a run.
If you do not specify it (Not set), the program will set ''Warning & Messages'' form as default.
Keywords: First result form, Displayed, After run.
References: None |
Problem Statement: 同一个EDR文件可以包含不同的换热器模块程序，也可以在同一时间打开、调整不同的模块。解决方案130400 讲述了怎样用 '自动传送' 功能从管壳换热器模块传送过程参数，和几何参数（只限于机械模块），到管壳换热器机械模块、空冷换热器或板纹式换热器，并用此功能打开相应的模块窗口。本解决方案讲述的是怎样在同一EDR文件下，手动建立、调整，和保存不同的换热器模块于同一EDR文件里。 | Solution: 两种方法手动建立、调整，和保存不同的换热器模块于同一EDR文件里：
1. 当从空白新建一个EDR文件时，用户会看到以下界面。
从此界面，用户可以选择他/她后期想运行和保存于同一EDR文件下的不同换热器模块。多个模块可同时被选择。例如 ，要在此EDR文件里打开、运行和同时保存管壳换热器模块传，和管壳换热器机械模块、空冷换热器及板纹式换热器，用户应该选择如下。
用户会看到此四个模块被同时打开。
用户现在可以同时在这个不同的模块的窗口里进行操作。
第二种方法：当用户已经打开并处于某一模块的界面下时。
2. 在此情况下，用户可以直接点击位于程序界面上方的相应换热器模块按键，直接打开相应模块。如下图所示。
点击相应按键，相当于在方法1里所描述的在EDR程序启动时选择相应的模块选项。
在要运行某个换热器模块程序时，用户应该首先选中相应的模块程序窗口，然后点击程序界面上方的 '运行(Run)' 键，或到Run菜单，或用热键F5运行相应的模块。此命令是运行当前被选中界面窗口的模块，其他在背景里的换热器模块不会被运行。
用户现在可以到File/Save或Save As，去保存次EDR文件。这个EDR文件将包含所有以打开的换热器模块。
像在解决方案130400 中描述的，当此EDR文件下次被打开时，在起始窗口里这些此前被保存的模块会被以加粗形式标出，用户可以选择同时打开他们。
请注意，用户需要拥有相应的换热器模块的授权，才能运行相对应的换热器模块。
如需要删除/移除某一模块，请参照解决方案126021。
Keywords: 不同的，换热器模块，同时，运行，保存
References: None |
Problem Statement: 在Aspen EDR程序里，用户在程序界面的顶端菜单里能找到File | Description选项。它是用来做什么的？它和程序内部Input | Problem Definition | Headings/Remarks选项的区别是什么？ | Solution: File | Definition选项和Input | Problem Definition | Headings/Remark界面的输入界面是一样，但是它的信息不会在程序的TEMA参数报表里体现出来。
如果用户在Input | Problem Definition | Headings/Remarks界面写入任何信息，相应的同样的信息会在输出项的Results | Results Summary | TEMA Sheet 界面被即时更新，得以体现。但是在File | Description选项里输入的信息不会就被反映到结果输出的Results | Results Summary | TEMA Sheet表格里。
在某些情况下，这种应用很有用。例如，当用户相对次EDR模型标注一些个人或保密信息而同时又不想其他用户会接触到此模型运算结果的用户或客户知道时，可在File | Description选项填入这些信息，因为这些信息不会在结果输出界面的TEMA表格里体现出来或被打印出来。
Keywords: File, Description, Headings, Remarks, 描述，TEMA 表格
References: None |
Problem Statement: Aspen Shell & Tube Exchanger has two different vibration methods; HTFS proprietary and TEMA. Details of the HTFS methods can be found from the HTFS Research Network at http://www.aspentech.com/htfs/resnet.asp and the TEMA methods from the Standards of the Tubular Exchanger Manufacturers Association handbook.
Previously in Aspen Shell & Tube Exchanger, results for both methods were automatically presented, but in Aspen Shell & Tube Exchanger V7.20, the default option has been changed where now only the HTFS analysis results are given. Described below is how you can view the TEMA vibration results within the program. | Solution: From Input | Program Options | Methods/Correlations | General tab, the Vibration analysis method can be set. The options are;
Full HTFS analysis
Simple TEMA analysis
HTFS and TEMA analysis.
When the case is run, the vibration results can be viewed from Results | Thermal/Hydraulic Summary | Vibration & Resonance Analysis, where the first two tabs show the HTFS methods and the last two tabs TEMA results.
The main difference between the calculation methods is that Aspen Shell & Tube Exchanger considers the full length of the tube, whereas the TEMA method considers each individual span in isolation.
Further information on vibration can be found fromSolution 125374.
Keywords: Vibration Analysis, Shell & Tube
References: None |
Problem Statement: The Exchanger Design and Rating (EDR) program can be linked to Aspen HYSYS for the detailed calculation of Shell and Tube Exchangers.
Normally from a Heat Exchanger object in HYSYS, the EDR program can be selected from the Design tab under Parameters from the Heat Exchanger Model drop down list. Once this is selected the EDR-Shell&Tube tab becomes active so that the geometry data can be entered. If, however, EDR does not appear in the list, then this | Solution: describes how it may be set, assuming that you have both HYSYS and EDR V7.20 installed on the computer.Solution
Registry settings are used for the two programs to see one another. The registry settings entries that are available may depend upon the order in which HYSYS and EDR have been installed. The following procedure outlines how this may be set, where it is necessary to have Administration rights to the machine.
1. From Start | Run enter Regedit and OK
2a. Assuming you have a 32 bit operating system, navigate to HKEY_LOCAL_MACHINE\SOFTWARE\AspenTech\HYSYS\24.0\Compatibility\Aspen Exchanger Design and Rating
2b. For Windows 64 bit operating system, the path is slightly different at HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\AspenTech\HYSYS\24.0\Compatibility\Aspen Exchanger Design and Rating
3. Under here you should see 3 keys, default, 1 and CurVer.
4. It is likely that key 1 is missing? If so follow the following steps;
a. Under the keys, right mouse click and select New, String Value
b. Right mouse click on the New key and rename to 1
c. Modify key 1 and set the Value data to 24.0
5. Close Regedit
Now start HYSYS where EDR should now appear in the drop down selection.
Alternatively, download the appropriate attached registry file and double click to install the registry settings.
Keywords:
References: None |
Problem Statement: In Input >Exchanger Geometry > Nozzles > Shell side nozzles, when any ASME option in nominal pipe size is selected, the actual ID shell side nozzle diameter value is not changing.
After running the file, the Input Error 1122 appears in Results > Results Summary > Warnings & Messages
How can I get rid of this error? | Solution: When “use existing layout” option is used, nozzle sizes are locked in as well. This option needs to be changed to “new (optimum) layout”
To change this options, go to Input > Exchanger Geometry > Geometry Summary
Select New ( Optimum) layout from the Tube Layout dropdown list
Keywords: Input Error 1122, nozzle diameter, actual ID
References: None |
Problem Statement: Can a vertical flooded evaporator be designed using Aspen Shell & Tube Exchanger? | Solution: A vertical flooded evaporator is usually used in large ammonia systems. One of the current limitations of Aspen Aspen Shell & Tube Exchanger is creating vertical flooded evaporator with BXM geometry. Currently Aspen Aspen Shell & Tube Exchanger can handle horizontal flooded evaporator with BXM geometry.
A
Keywords: EDR, heat exchanger, vertical, BXM shell.
References: None |
Problem Statement: Why is the allowable number of baffles too low? | Solution: Allowable number of baffles is calculated on the basis of tube length and baffle spacing. If you observer Aspen Shell & Tube Exchanger (formerly Aspen Tasc+) is allowing too few number of baffles, you might have specified too high baffle spacing, or too low tube length. Please check the values and units of baffle spacing and tube length.
Keywords: baffle, number
References: None |
Problem Statement: Temperature Crosses: Possible and Impossible scenarios | Solution: The term ?Temperature Cross? can have a number of different meanings. Sometimes it relates to something that is physically impossible in a heat exchanger, sometimes it does not. Sometimes it simply imposes restrictions on the type of exchanger configuration that can be used.
To begin with it is useful to consider various types of heat load curve, that is graphs of temperature T against heat load Q, for two streams in an exchanger. An example is shown in Figure A. In this particular example, the temperature range of the hot stream (the upper, red line) is entirely above the temperature range of the cold stream (lower, blue line). The graph is drawn with the streams in counter-current flow. Because the temperature ranges of the hot and cold streams do not overlap, any configuration of exchanger can be used, counter-current, co-current, cross-flow, or any more complex configuration, for example where one of the streams flows in two or more passes.
Next consider the heat load curve in Figure B. This is similar to Figure A, except that the temperature ranges of the hot and cold streams overlap. This is often called a temperature cross application, but the term temperature range overlap is a clearer description. The overlap mean that a purely co-current exchanger is impossible, while other exchanger configurations, such as cross-flow or multi-pass exchangers may be possible if the range overlap is small.
The next type of curve, Figure C, shows the most basic type of temperature cross. The exit (lowest) temperature of the hot stream is below the inlet (lowest) temperature of the cold stream. This type of temperature cross cannot occur in any heat exchanger, whatever its configuration. There is no way in which the hot stream can be cooled below the lowest temperature of the cold stream.
There is a variant on this simple temperature cross, which is shown in Figure D. If only the stream inlet and outlet temperatures are considered, there does not appear to be a problem. However, at a point between the ends, the cold stream is at a higher temperature than the hot stream. This is referred to as an internal temperature cross. It too is not physically possible. No exchanger configuration could deliver the duty show in Figure D.
Figures A ? D all show two stream curves, in a standard counter-current flow, where temperature is plotted against heat load. It is also useful to consider temperature profiles, that is graphs of stream temperature against distance along the exchanger. Heat load curves often approximate to straight lines, particularly for single phase streams, but temperature profiles are more complicated, since they depend on the variation of heat transfer coefficient and temperature difference along the exchanger. Temperature profiles depend on the exchanger configuration, and can be drawn for exchangers with multiple passes.
An example of temperature profiles for a two-pass shell and tube exchanger is shown in Figure E. The hot shellside stream enters at the same end of the exchanger as the cold tubeside stream. For simplicity, the streams are single-phas, with constant specific heat and constant heat transfer coefficients. There is a small temperature range overlap. Stream to stream temperature differences are largest near the front head (tubeside inlet end), so temperature changes are largest there. The cold stream temperatures are everywhere below the hot stream temperatures.
If in this exchanger, the shellside fluid entered near the rear head, the temperature profiles would be as shown in Figure F. Inlet and outlet conditions and all stream parameters are the same. The temperature rise in the first tubeside pass is now much more uniform along the exchanger. The more interesting feature is the second tubeside pass, which shows a local temperature cross. Here the temperature rises until it reaches the temperature of the shellside stream. At that point there is no temperature, difference, and no heat transfer, so the temperature of the tubeside stream does not change. Further along the exchanger, nearer the front head, the shellside stream temperature is falling, due to cooling by the first tubeside pass. In the second tubeside pass, the temperature is above that of the shellside stream, so the tubeside temperature falls slightly, below the maximum reached at the point where it crosses the shellside stream.
A local temperature cross like that in Figure F can happen when one stream pass is exchanging heat simultaneously with two or more other stream passes. All the basic thermodynamic and heat transfer equations are obeyed.
The modeling assumption that the tubeside passes exchange heat simultaneously with the shellside pass is used for all exchangers with axial flow. Baffled shellside flow is clearly complicated, but if there are a large number of baffles, it can be treated as overall axial flow. Since it flows over each tubeside pass in each baffle space, the approximation that the shellside fluid is exchanging heat simultaneously with all tubeside passes is also generally a good one. Even if the heat transfer with two or more passes is locally sequential rather than simultaneous, the possibility remains that a hot shellside fluid is cooled so much by one tubeside pass that it finds itself below the temperature of the other tubeside pass, causing it locally to cool, rather than heat this second pass.
Local temperature crosses are thus a physically real phenomenon, not an artifice of the modeling. They do however only occur near the limits of normal exchanger operation, and only for multipass exchangers, and in most E-shell cases, only when the shellside fluid exits near the front head.
Keywords: temperature cross, exchanger, phase change
References: None |
Problem Statement: When I go to Results | Thermal / Hydraulic Summary | Flow Analysis, the Shell Side Flow Fractions on the table for the Flow Analysis do not add up to one.
 | Solution: The flow Analysis shows fractions of the shellside flow. The flow direction on the shellside due to the baffles is not pure crossflow, but a combination of cross flow and longitudinal flow. The departure from crossflow will depend upon the baffle spacing and cut. The flow is further complicated by manufacture tolerances for assembly, which cause clearances between the tubes to baffle or baffle to shell for example.
The various flow streams are shown below where sometimes there is different terminology used;
Crossflow (B) Crossflow
Bypass (C) Shell ID - bundle OTL
Inline pass partion (F) Pass lanes
Window flow (W) Window
Tube/baffle leakage (A) Baffle hole - tube OD
Shell/baffle leakage (E) Baffle OD - shell ID
Using the stream letter and letting F denote a fraction of the total flow rate in the heat exchanger then
F(W) = F(B) + F(C) + F(F)
F(A) + F(E) + F(W) = 1
This is why the sum of all values will not add up to one.
Keywords: Crossflow, flow analysis, fraction
References: None |
Problem Statement: Within the Exchanger Design and Rating Suite, EDR, different pressure units may be set on the individual input forms. In the versions older than V8.0, there is a units set of mmHq, which is a mis-type for mmHg (mm of mercury) that is also available.
If this unit is set, then the input file will load correctly into EDR versions up to V7.3.2. If the file is read into V8.0 or greater, then the pressure will be incorrectly read into the program. This may be noted from the pressures and estimated/allowable pressure drops that may be in the Process Data input forms or the pressure levels in the Hot/Cold Stream Properties. | Solution: From EDR V8.0 onwards, this incorrect label for the pressure units has been removed. If files are to be transferred to EDR from older versions, then it is recommended that first all pressure units are re-set so that mmHq is not used. The simplest way to achieve this would be to globally change the units of measure, change to a different unit set and then back to the original set, save the file and then open in EDR V8.0 onwards.
Keywords: mmHq, incorrect pressures
References: None |
Problem Statement: We know the patches (if applicable) for various versions of Aspen Exchanger Design & Rating (EDR) programs can be found on AspenTech support website at http://support.aspentech.com Is there any shortcut to access the summary page of all the patches available for Aspen EDR programs that have been released? | Solution: All the released patches for Aspen EDR programs can be downloaded from Aspen support website. The normal route is to go to http://support.aspentech.com, click 'Patches' at the up-left corner of the page.
There is a shortcut, by going to the link below http://support.aspentech.com/webteamasp/My/FrameDef.asp?/webteamasp/AllServicePacks.asp , where users are promoted to the webpage straight away where they can select the desirable product name directly from the corresponding product list under the corresponding product group.
Under 'Process Engineering Patches' section, find and click 'Aspen Shell & Tube Exchanger' in the product list, download the corresponding patches to the version you are using and install the patches in Forward Sequence.
More details on checking the patch releases and the corresponding build numbers can be found in TechnicalSolution 131395.
Keywords: EDR patches, support website, shortcut, install pacthes
References: None |
Problem Statement: Why inlet baffle spacing is zero in design for U type bundle? | Solution: The default baffle spacing at inlet for U bundle is 0. It means the first baffle is at the junction of straight tubes and U bend. This is where the blanking baffle would normally be.
Keywords: U bend, U tube bundle, inlet baffle spacing, inlet, baffle spacing zero, 0
References: None |
Problem Statement: For a condensing stream, you should determine if your case is closer to integral or differential condensation. More condensate will be present at any given temperature with integral condensation versus differential condensation. In the heat exchanger design, this results in a higher mean temperature difference for integral condensation compared to differential condensation.
How can you specify this on Aspen Shell & Tube Exchanger? | Solution: The condensation type can be changed within the Property method Tab for the Hot Stream Compositions menu. This is valid when you select to retrieve the properties using the B-JAC database.
It should be noted that Aspen Shell & Tube Exchanger defaults to integral.
Integral condensation assumes that the vapor and liquid condensate are kept close enough together to maintain equilibrium, and that the condensate formed at the beginning of the condensing range is carried through with the vapor to the outlet. Vertical tube side condensation is the best case of integral condensation. Other cases which closely approach integral condensation are: horizontal tube side condensation, vertical shell side condensation, and horizontal shell side crossflow condensation (X-shell).
In differential condensation the liquid condensate is removed from the vapor, thus changing the equilibrium and lowering the dew point of the remaining vapor. The clearest case of differential condensation is seen in the knockback reflux condenser, where the liquid condensate runs back toward the inlet while the vapor continues toward the outlet.
Shell side condensation in a horizontal E or J shell is somewhere between true integral condensation and differential condensation. If you want to be conservative, treat these cases as differential condensation. However, the industry has traditionally designed them as integral condensation.
Keywords: Integral condensation
Differential condensation
Heat Exchanger
References: None |
Problem Statement: The flow of the shell side fluid can impart energy to the tubes in a heat exchanger that may cause them to vibrate.
The Tubular Exchangers Manufacturer Association (TEMA) Handbook 9th Edition in Section 6 presents a method for determining the flow induced vibration, where this | Solution: describes how the Fluid Elastic Instability (FEI) results presented may be interpreted.Solution
If the ?Simple TEMA Analysis? vibration analysis method has been selected from Input | Program Options | Methods/Correlations | General tab, then when a case in run, the Vibration performance is shown in Results | Thermal / Hydraulic Summary | Vibration & Resonance Analysis | Simple Fluid Elastic Instability (TEMA) tabs.
For FEI, warnings are issued based upon the crossflow to critical velocity ratio and are shown at different axial locations along the exchanger. For the baffled region, two locations are show; CC-Window (equivalent to tube location 2, outside baffle overlap for the HTFS method) and CC-Overlap (equivalent to tube location 4, inside baffle overlap for the HTFS method).
For the FEI (TEMA) method, users should ensure that the crossflow to critical velocity ratio is less than 1 otherwise a ?Yes? vibration indication is given. If the ratio is less than but approaching 1, then a ?Possible? vibration indication is shown.
Keywords: None
References: None |
Problem Statement: In Aspen Shell & Tube Exchanger program, where can I find the local crossflow velocity values and crossflow fractions for detailed tube locations (as described in | Solution: 125368) in the inlet, mid-space and outlet regions of the exchanger?
Solution
The local crossflow velocities and corresponding crossflow fractions can be found on Results | Thermal / Hydraulic Summary | Vibration & Resonance Analysis | Resonance Analysis tab.
Scrolling the table to the right-hand side, users will see the outputs for relevant tube locations in different regions (normally inlet, mid-space and outlet) of the exchanger.
Keywords: Local Crossflow Velocity, X-flow Velocity, Tube Row Locations, inlet, Mid-space and Outlet Regions
References: None |
Problem Statement: Like most AspenTech Engineering programs, when opening an existing EDR file, users can either choose to double-click the EDR file directly, or users can open an EDR program from scratch and navigate to the folder where the existing EDR file lies and select to open the file.
Or
When using the later method (open program from scratch first), is it necessary to open an application that is the same application type as the existing EDR file? | Solution: It is not necessary to open an application with the same application type as the existing EDR file. No matter which application users choose to open from scratch (i.e. Shell&Tube Exchanger, Shell&Tube Mechanical, Air Cooled Exchanger, Plate Exchanger, Plate Fin Exchanger and/or Fired Heater), the EDR program will automatically detect which application(s) the existing EDR file contains and will open the this EDR file using all the corresponding sub-applications.
Keywords: open existing EDR file, same application type, necessary
References: None |
Problem Statement: Two phase flow in a horizontal tube can adopt many geometric configurations of the distribution between the liquid and gas phases, which are commonly known as a??flow patternsa?? or a??flow regimesa??.A
When subcooled liquid flows through a horizontal tube heated with a constant heat flux, the heat transfer coefficient varies along the length of the tube and is related to the changing structure of flow pattern within the tube.
Flow in horizontal channels is complicated by the separation of the phases due to gravity.
A? Bubbly: The flow pattern is similar to that in vertical tubes, except that the bubbles tend to travel in the upper half of the tube.
A? Plug: This is similar to slug flow as in a vertical tube where the gas bubble travels in the upper half of the tube.
A? Wavy: As the vapour and hence velocity increase, the interface becomes disturbed by waves travelling in the direction of flow.
A? Annular: A high vapour velocity results in a gas core with liquid around the periphery of the tube. Under gravity, liquid can fall to the bottom of the tube giving the possibility of intermittent dryout in wavy flow and progressive dryout in the upper circumference in annular flow.
At high liquid velocities the influence of gravity is less, the phase distributions become more symmetrical and the flow patterns become closer to those in vertical flow.A | Solution: In a heated tube the heat transfer and pressure drop are both dependent upon the flow pattern. Therefore, to predict these reliably, knowledge of the prevalent flow pattern is required. Flow patterns may be predicted from either;
Empirical flow pattern maps: Data collected from flow pattern observations may be presented in terms of flow pattern maps, where a two-dimensional plot attempt to separate the flow patterns into particular areas.
Theoretical flow pattern maps: To construct a theoretical flow pattern map, the mechanisms that cause the transition between successive flow patterns must be identified and equations generated to account for both the physical properties and tube geometry.
From the Exchanger Design and Rating (EDR) program for Aspen Shell & Tube Exchanger, Aspen Air Cooled Exchanger and Aspen Fired Heater, the flow patterns within the tubes are determined and can be found in:
Shell and Tube: Results | Calculation Details | Analysis along Tubes | Interval Analysis tab
Air Cooled:A A A A A A Results | Calculation Details | Interval Analysis - Tube Side | Pressure Change tab
FiredHeater:A A A A A Results | Calculation Details | Stream Details | Stream x tab
For horizontal tubes the flow pattern map of Taitel and Dukler (1976) is used.
Taitel, Y., and Dukler, A. E. (1976).A a??A Model for Predicting Flow Regime Transitions in Horizontal and Near Horizontal Gas-Liquid Flowa??.A A.I.Ch.E.Journal Vol. 22, pp. 47-55.
Keywords: None
References: None |
Problem Statement: The Tubular Exchanger Manufacturer Association (TEMA) sheet gives a document template, which shows the process conditions, stream physical properties and geometry of a heat exchanger. Given on lines 37 to 39 are the nozzle dimensions for both the shell and tube side.
This | Solution: describes how users may vary the nozzle dimensions shown on the TEMA sheet to be either based on the inner diameter (ID), outer diameter (OD) or the Nominal pipe size diameter.Solution
From the Input | Exchanger Geometry | Nozzles, users under the Shell side Nozzles or Tubeside Nozzles tab can specify the nozzle diameters in terms of ID, OD or Nominal diameter. In addition, a nominal pipe size can be selected, where the program will then populate the nozzle diameters values.
At the bottom of the input form under ?Nozzle diameter displayed on TEMA Sheet?, the dimension can be specified, that will then be past across to the TEMA sheet
Keywords: TEMA Sheet, Nozzle dimensions
References: None |
Problem Statement: Cannot change baffle configuration after running a case in 7.2.1
Open the attached case v7.2.1: AM5-103C- test 7.2 not run.EDR
Run the simulation.
Go to Exchanger Geometry\Baffles and Supports and try to change the baffle type. Even when the software allows the user to select the different baffle types, the other menus remain inactive.
The problem is not present in 7.1 | Solution: Improvement in 7.2
This is an X-shell. An X-shell has no (flow) baffles, it has support plates. The default baffle type is unbaffled
The baffle thickness is left accessible. The note at the bottom of the screen indicates that the thickness refers to baffle or support plates. No other baffle related iputs are needed.
On the Tube supports tab, there is an option to specify the number of tube supports for X-shells.
Keywords:
References: None |
Problem Statement: When using the Aspen Shell and Tube Exchanger program in design mode, from Input | Program Options | Design Options | Process Limits tab, the minimum and maximum velocities for the hot or cold side can be set.
In most cases only the minimum and maximum tube side velocity limits affect the design, since these may affect the maximum and minimum limits on the number of tubes per pass and hence restrict the range of shell size investigated, for a given number of passes and shells in parallel.
The restrictions on shell side velocities have a similar effect for axial shell side flows, but are not used for baffled or other crossflow exchangers. The ranges of baffle spacing and shell diameters permitted are the main parameters affecting shell side velocities, and these should be used instead of explicit velocity limit specification for baffled shell side exchangers.
The | Solution: describes the range of tubeside velocities normally used inside tubes, which can be limited due to erosion.Solution
Erosion is the deterioration of the tube surface due to the action of the fluid flowing over it can be intensified if the fluid contains solid particles in suspension. The following values are taken from ?Heat Exchangers - Selection, Design and Construction? by E.A.D Saunders, Longman Group Limited, 1988 for salt water flowing inside tubes of various alloys unless stated otherwise.
Keywords: Velocity range, Erosion
References: None |
Problem Statement: How do I make the top of the triangle face up when I use a 30 degree triangular tube pattern with a vertical baffle cut? | Solution: There are two ways you can do it.
1. Use 60 degree rotated triangular tube pattern. Or,
2. Choose horizontal baffle cut. Make sure ?New (optimum) Layout? is chosen under Input || Exchanger Geometry || Geometry Summary || Tube Layout. Run the file. The triangle top will be facing up. Now, change Tube Layout from ?New Optimum Layout? to ?Use existing layout?. Then change the baffle cut to vertical. Run the file. In this case thermal and pressure drop calculations will be performed using vertical baffle cut but tubesheet layout will not change.
Keywords: Triangle, up, vertical baffle cut.
References: None |
Problem Statement: Cannot launch Aspen Exchanger Design & Rating by the error 430. | Solution: This is JapaneseSolution. Please see attached pdf file. (Japanese)
Keywords: Error
EDR
References: None |
Problem Statement: How do I transfer data from HTRI to Aspen Shell & Tube Mechanical? | Solution: Go to the main program menu, click on File and then Open. Choose the option HTRI output (*.DBO, *.OUT) in the Files of Type dropdown menu and click Open.
Keywords: None
References: None |
Problem Statement: In Aspen Exchanger Design & Rating (EDR) programs, from the top menu users can find File | Description option. What is it used for? What is its difference from the Input | Problem Definition | Headings/Remarks tab inside the programs? | Solution: The File | Description option has the same input interface as the Input | Problem Definition | Headings/Remarks tab where users can input notes/remarks/annotations like Company, Data, project reference etc, but it is not related or synchronized with TEMA specification sheet outputs.
If users specify anything on Input | Problem Definition | Headings/Remarks tab, the same information will appear on the Results | Results Summary | TEMA Sheet tab. However, any inputs on File | Description option from the top menu will not be contained or reported in the TEMA specification sheet outputs, though File | Description option contains the same input catalog as Input | Problem Definition | Headings/Remarks tab.
This is useful when users want to put some private or confidential remarks/annotations for the EDR case, but does not want this information to be displayed on TEMA specification sheet, which probably later on will be printed out and shown to other users or clients.
Keywords: File, Description, Headings, Remarks, TEMA sheet
References: None |
Problem Statement: The Mass heat of vaporization reported in Aspen HYSYS may not match the latent heat values displayed in the Aspen Exchanger Design & Rating (EDR) results. You may find a latent heat value in EDR that is less than the Mass heat of vaporization for the corresponding stream in Aspen HYSYS. | Solution: The terms used in these two programs may be confusing. An explanation is shown below on how Aspen EDR determines the latent heat. For a single component, the latent heat is defined as the saturated enthalpy of the vapor minus the saturated enthalpy of the liquid at the same temperature.
For a mixture, the latent heat is the enthalpy of the vapor minus the enthalpy of the liquid at the same temperature, taking into account that the stream is not all vapor or liquid. In practice you need to do this over a finite (but small) temperature range where you will need to subtract the sensible heat change for the liquid and vapor.
The equation for latent heat is derived from an energy balance where the duty supplied is used to heat both the liquid and vapor phases and vaporize the fluid. As an approximation the latent heat is found from:
Latent Heat = ( dh/dx ) - ( (1 - x)*Cpl + x*Cpg ) * dT/dx
where:
dT = small change in temperature
dh = change in enthalpy over dT
dx = change in quality over dT
x = average quality within temperature range
Cpl, Cpg = average specific heats of liquid & vapor within temperature range
You can view the value for Mass heat of vaporization in HYSYS by double clicking the heat exchanger on the flowsheet, then go to 'Worksheet' tab and select 'Properties' from the list on the left side. You can view the Latent heat value in Aspen EDR by going to Results | Result Summary | TEMA Sheet tab section or Results | Calculation Details | Analysis along Shell/Tubes | Physical Properties tab.
So, if there is no change in temperature and complete phase change for a pure component, then its 'Mass heat of vaporization' in HYSYS will be the same as 'Latent heat' in Aspen EDR.
However, in the case of a mixture, if we have complete phase change from 0 vapour fraction to 1 vapour fraction we will have a temperature change so, according to the above equation, latent heat will be lesser than the term dh/dx due to heating required for the liquid and vapor phases.
Keywords: Latent heat, Mass Heat of Vaporization
References: None |
Problem Statement: One Exchanger Design & Rating (EDR) file can have multiple applications in it and user has the option to load these applications/sub-programs every time within the EDR file. | Solution: 130400 describes how to transfer process data from a Shell&Tube application into Shell&Tube Mechanical or AirCooled or Plate Fin application, and use this auto-transfer feature to open other applications. ThisSolution describes how to manually create multiple types of applications with different sub-programs for different types of heat exchangers from scratch, and how to run and save them, within the same EDR file.
Solution
There are two ways one can open, run and save various exchanger modeling applications within the same EDR file:
1. While opening and creating an EDR file from scratch, one will see the below interface.
This is the interface where one can select all the application types he/she wants to manipulate and save later within the EDR file. For example, to open Shell&Tube, Shell&Tube Mechanical, AirCooled and Plate Fin in this EDR file, one can select them as shown below, and click 'OK'.
One will then see the four applications are opened at the same time.
One can now start manipulating these applications by inputting data and running these applications.
In case one has opened and has been in the interface of one application already, below is the other way to open other application within the same EDR file.
2. One can click the corresponding buttons for each application, located on the top bar of the program diagram, as shown below.
Clicking them is equivalent to selecting the corresponding application options when opening the EDR file, as described in Way 1.
When running each application, one should firstly select/highlight/activate the desirable application window, by clicking the cursor on the window. Then one can click the 'Run' button , or go to Run option from the diagram's top menu or simply use F5 hot key to run this application. This commend is to run the selected/highlighted application, while other applications at the background won't run.
One can now go to File/Save or Save as from the top menu, to save the EDR file which will contain all these different applications.
As described inSolution 130400, when this EDR file is being opened next time, the applications contained in this EDR file will be highlighted in bold, and the user can choose to open any of them at the same time.
Please be aware that one will need to have the application/sub-program license to run the corresponding application.
If you want to remove any of the individual applications, please refer toSolution 126021.
Keywords: Run, Save, Various, Different, Multiple, exchanger model, Applications, types, Same time
References: None |
Problem Statement: What is the meaning of Warning 1354: Flow reversal of liquid at the top of tubes is likely to occur since the Wallis dimensionless gas velocity is less than 0.5. You should consider a design revision to increase the tubeside velocity. | Solution: Here is the explanation of flow reversal.
a) At low gas flowrates the liquid falls down the tube as a film and flows out the bottom
b) As the gas flowrate is increased, waves are formed on the liquid film and it can be carried partly upwards from the point of injection. This is known as flooding
c) As gas velocity is increased further liquid flow can go both upwards and downwards until the point is reached where all the liquid flows upwards.
d) If the gas velocity is now decreased, then point is reached where the liquid flow may creep below the point of injection and this is known as flow reversal
The Wallis dimensionless vapour velocity can be found in DR 1 (HTFS Research Network) Vertical Thermosyphon Reboilers, Part 2: Analysis of the System page 15 or DR12 TASC, Part 1: Technical Manual, Section 10.4, and is given by;
Ugo ( Rho g ) ^0.5 / ( gn Do (Rho l - Rho g) ) ^0.5
Where,
Ugo = superficial vapour velocity
Rho = Density, where l is liquid phase and g vapour
Gn = Gravity
Do = Outer diameter
With a thermosyphon, in both tubes and nozzles you want to ensure that you are above the flooding predictions so that liquid is swept out of the tubes. However, probably more important is that the flow reversal criterion are exceeded (this is usually a stricter criterion than for flooding) as you do not want any condensate to fall back into the exchanger or down the tubes.
DR12 page 89 mentions:
Accurate prediction of flooding and flow reversal is not possible and these criteria should be regarded as approximate guidelines that should preferably be exceeded by a significant margin in design
Other than this it is probably best to go back to the original reference, Wallis, G.B., (1962) The Transition from Flooding to Upwards Co-current Annular Flow in Vertical Pipe AEEW-R 7994.
The HTFS Handbook sheet TP8 Flooding Phenomena in Two-Phase Flow will be a useful document to read for the background on flooding.
For efficient, smooth operation of a vertical thermosyphon reboiler the vapour velocity leaving the tubes must be sufficient to ensure that any liquid contained in the two phase mixture is carried over back to the column. The same applies to vertical pipes in the external circuit leading back to the column in any thermosyphon reboiler.
There are a number of criteria used to determine whether flow reversal will occur or not. Wallis dimensionless gas velocity is one of them. Further details can be seen in HTFS Design Report DR12 Part 1 section 10.4.
Now we come to the questions about whether the problem needs to be avoided (i.e., is it real) and how to avoid the problem. Firstly the calculations are only approximate and if you have similar equipment operating satisfactorily under similar conditions then it may well work. However, as a general rule, try to avoid the problems if possible.
In order to avoid the problem, you need to increase the vapour velocity in the tubes. You can do this by a number of ways:
(a) Reduce the flow around the external circuit (eg reduce the available head, increase the single phase pressure drop in the inlet pipework, reduce the temperature driving force).
(b) Increase the amount of fluid vaporized (eg by increasing the temperature driving force).
(c) Increase the vapour velocity by reducing the pressure (may not be possible).
(d) Increase the velocity in the heat exchanger by changing the geometry (reduce the shell diameter, reduce number of tubes or if the exchanger has already been already built, plug tubes). If tubeside velocity increases and film coefficient would increase. This may compensate to have same heat transfer. More vapour will increase the head available for driving the recirculation.
Unfortunately some of the above suggestions may affect more than one parameter and may turn out to be counter productive. For example, increasing the temperature driving force will increase the amount of fluid vaporized but it will also tend to increase the recirculation flow around the circuit. Very often the only way to tell which effect will be most pronounced is to try it with Shell&Tube.
Keywords: Warning 1354, Flow reversal, Wallis dimensionless gas velocity
References: None |
Problem Statement: Installing AES v7.3 and AES v7.2 caused the sytem to reboot | Solution: 1. Uninstall the Aspen SLM software and Aspen products from Add/Remove Program
2. Open Window Explore, and delete all Aspen folders on the C drive
3. On the Window Explore address field, type %temp% and hit enter key. Delete all the files and folders on the Temporary folder.
4. Using regedit, manually remove orphaned registry keys relating to Aspen
5. Run the Microsoft cleaning utility, found on the Microsoft website.
6. Re-start the system or reboot.
7. Install the SLM Tool 7.3 Software from DVD#1
8. Installed the AES V7.3 software.
9. Run the AES program
Keywords: Installation, v7.3, v7.2, regedit, and system rebooting
References: None |
Problem Statement: In Aspen Shell & Tube Exchanger, you may notice the difference in unsupported span length and flow velocity for Resonance Analysis (HTFS) and Fluid Elastic Instability (TEMA). | Solution: You can view the Vibration & resonance analysis under Results | Thermal / Hydraulic Summary | Vibration & Resonance Analysis tab. Results are only available once the simulation run has been performed. This tab contains details of Fluid elastic instability & Resonance analysis performed according to HTFS methods and also according to TEMA methods.
HTFS performs the vibration analysis for a set of representative tubes in inlet, mid-space and outlet region (or U bend if it is a U type bundle). Please see thisSolution link for more information on representative tube set used by HTFS http://support.aspentech.com/webteamasp/KB.asp?ID=125368. Program calculates the unsupported span length and flow velocity for all the representative tubes for three regions across the length of the heat exchanger and all these parameters can be viewed under Results | Thermal / Hydraulic Summary | Vibration & Resonance Analysis | Resonance Analysis (HTFS) tab.
However, TEMA analysis for Fluid Elastic Instability reports the longest unsupported span for each region which means the length reported in Results | Thermal / Hydraulic Summary | Vibration & Resonance Analysis | Simple Fluid Elastic Instability (TEMA) tab will be the maximum unsupported span length, where for example in the inlet region it will be the inlet spacing plus the baffle pitch.
Keywords: None
References: None |
Problem Statement: How can I create a Tasc+ input template file? | Solution: A template file can be created in Tasc+ using the EDT extension. Create a standard Tasc+ input file and then save it using a *.EDT extension. Using this method, you can obtain a file with the geometry (size and type) and specifications without the process information.
Keywords: template, extension, file, input
References: None |
Problem Statement: 是否可用Aspen Shell & Tube Exchanger 程序来模拟虚拟防冲管？如果可以，如何定义相应设定？ | Solution: 是的，Aspen Shell & Tube Exchanger 程序可以模拟虚拟防冲管。
首先，你需要到Input > Exchanger Geometry > Nozzles > Shell/Tube Side Nozzles 界面去设定''Yes impingement''。
然后你要到Input > Exchanger Geometry > Nozzles > Impingement 界面去定义''Dummy tubes''。
然后用户就可以在界面下方开始输入相应的dummy tube的参数设定，比如管行数。
Keywords: Chinese-
References: None |
Problem Statement: How does one accurately generate the properties of an Electrolyte system in a Heat Exchanger in Aspen HTFS+? | Solution: If there is an electrolyte system in your heat exchanger, Aspen Properties ELECNRTL is the recommended physical property method. ELECNRTL uses special density models to accurately predict the density of aqueous electrolyte systems, but without running ELECWIZARD inside Aspen Properties, the property method will be simply reduced to NRTL. Following information provides a detailed information about generating the physical properties of an electrolyte system in a heat exchanger in a HTFS+ program.
1. Go to Start | Programs | Aspen Tech | Process Modeling | Aspen Properties and open an Aspen Properties user interface. Select 'Template' option and select 'Electrolytes with Metric or English units' and open the Aspen properties.
2. On the Aspen Properties user interface, go to Data | Set Up and select the valid phases to Vapor-Liquid
3. Then go to Data | Components and add all your components, note that water is already add to your system.
4. Then on same page, click the 'Elec Wizard' button to invoke electrolyte wizard.
5. On the electrolyte wizard, click Next and add all available components to 'Selected components' list and under options, uncheck the 'include salt formation' check box if you are not expecting any salt formation. Also HTFS+ engines can handle only vapor-liquid-liquid systems and cannot handle solid-vapor-liquid systems in the exchangers, so un-checking the salt formation option will avoid any physical property conflicts.
6. Then click Next, Next and before Finish, uncheck the 'use true components' and complete the electrolyte wizard set up.
7. Now go to Data | Properties and make sure the property method selected is ELECNRTL.
8. Then click the Next button to complete the properties set up.
9. Then run the Aspen Properties and make sure you get a status of result available.
10. Save this file as *.Aprbkp format.
Now open the Aspen Tasc+ or Aspen Acol+ (now called Aspen Shell & Tube Exchanger and Aspen Air Cooled Exchanger respectively) interface and go to the properties section and depending upon the allocation of this fluid, go to either hot or cold stream composition page and select the physical property package as Aspen Properties. Then go to Advanced Options Tab and select the radio button (option 2) to import an existing aspen property backup file and navigate to the saved Aspen properties file and import.
Now go back to composition tab and specify the composition of the components and leave the ionic components to empty. Go to properties page and click the generate properties to generate the properties.
Instead of creating the aspen properties backup file, you can achieve the same by opening the Aspen Tasc+ interface and go to the properties section and depending upon the allocation of this fluid go to either hot or cold stream composition page and select the physical property package as Aspen Properties. Add all your components and specify the property method as ELECNRTL and then go to Advanced Options Tab and leave it to default check option 1. Click on Aspen Properties browser and Run the Electrolyte Wizard as mentioned above and save the file. Go to properties page and click the generate properties to generate the properties.
Keywords: Aspen Properties, Electrolyte, ELECNRTL, Properties.
References: None |
Problem Statement: When running Aspen Shell and Tube Exchanger, you may see the Input error 1124 The data input for E-Shell inlet nozzle loc. is unacceptable.
This | Solution: describes what the error means and how can it be eliminated.Solution
For an E shell, to set the flow to be counter or co-current, then from Input | Exchanger Geometry | Shell/Heads/Flanges/Tubesheets | Shell/Heads tab the E shell flow direction (inlet nozzle location) is used to set the location of the inlet nozzle. If it is set to;
Near rear head then the flow direction of the first tube pass will be in opposite direction (counter-current flow) to the shellside flow
Near front head, then the first tube pass and shellside flow will be in the same direction (co-current flow)
From Input | Exchanger Geometry | Nozzles | Shell Side Nozzles tab, the distance to front tubesheet can be set for both the inlet and outlet nozzles. For Shell&Tube V7.3 and older, use of this item would result in the Setting Plan, viewed from Results | Mechanical Summary Setting Plan & Tubesheet Layout, displaying the location of the nozzle as set. Sometimes this input item was used incorrectly in attempting to set co or counter current flow.
From V7.3.1, additional data checking was applied to prevent this, which results in the Input Error 1124, it the location of the nozzles set is in conflict with the E shell flow direction. To eliminate the error, delete the distance to the front tubesheet for the nozzles.
Keywords: error 1124, co-current, tubesheet, tube sheet
References: None |
Problem Statement: Horizontal/Vertical pass partition width how it is defined? Is it centre to centre of the tube holes on the tube sheet? | Solution: The Horizontal/Vertical pass partition lane width is measured from tube outer surface to tube outer surface (plain tube outer surface, ignoring any fins).
Keywords: width, pass, partition
References: None |
Problem Statement: How can someone specify the U-bend radius? | Solution: For U-tube units, where the Tube Layout option is not set to Use Existing Layout, the minimum U-bend diameter can be specified under Input | Exchanger Geometry | Bundle Layout.
This dimension is measured from tube center-line to tube center-line of the inner most U-tube.
By default the Minimum U-Bend Diameter will be 3 times the Tube Outside Diameter.
Keywords: U tubes
Radius
Heat exchanger
References: None |
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