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Problem Statement: The steam table property methods used in Aspen Plus are out of date. IAPWS-1995 is the current standard. When will this be added to Aspen Plus/Properties? | Solution: The IAPWS-95 property method is the current standards for steam table based on the International Association for the Properties of Water and Steam (IAPWS) formation 1995 for the thermodynamic properties of ordinary water substance for general and scientific use. This method will be available in Aspen Plus V7.2. This formation replaces the previous 1984 formation (IAPS-84), implemented in Aspen Plus as STEAMNBS and STMNBS2. The IAPWS-95 formulation overcame a number of shortcomings of IAPS-84 including weaknesses near the critical point (regarding the phase boundary and in its derivative properties such as isothermal compressibility) and when extrapolating beyond its range of validity. The IAPWS-95 formulation is in the form of a fundamental equation explicit in Helmholtz free energy. The residual part of the Helmholtz free energy was fitted to the following properties: (a) thermal properties of the single-phase region (prT) and of the vapor-liquid phase boundary (pr'rT), including the phase-equilibrium conditions (Maxwell criterion), and (b) the caloric properties - specific isochoric heat capacity, specific isobaric heat capacity, speed of sound, differences in the specific enthalpy and in the specific internal energy, Joule-Thomson coefficient, and isothermal throttling coefficient.
The IAPWS-95 formation covers a validity range for temperatures from the melting line (lowest temperature 251.2 K at 209.9 MPa) to 1273 K and pressures up to 1000 MPa. In this entire range of validity, it represents even the most accurate data to within their experimental uncertainty.
Region & Property
Estimated Uncertainty
Liquid - density
?0.001% to ?0.02%
Liquid - speed of sound
?0.03% to ?0.2%
Liquid - isobaric heat capacity
?0.1%
Liquid at ambient pressure - density
#0.0001%
Liquid at ambient pressure - speed of sound
?0.005%
Gas - density
?0.03% to ?0.05%
Gas - speed of sound
?0.15%
Gas - isobaric heat capacity
?0.2%
In the stable fluid region, the IAPWS-95 formulation can be extrapolated beyond the limits of validity listed above. The model behaves reasonably well when extrapolated to pressures up to about 100 GPa and temperatures up to about 5000 K for density and enthalpy of undissociated water.
Keywords: None
References: Wanger W. and A. Prub, The IAPWS Formation 1995 for the Thermodynamic Properties of Ordinary Water Substance for General and Scientific Use, J. Phys. Chem. Ref. Data, 31(2), 387- 535, 2002 |
Problem Statement: Is it possible to run just one block in a multi-block simulation file? If so, how can I do it? | Solution: Various simulation objects can be activated and deactivated. When deactivated, they still need to be completely specified to run the problem, but deactivated simulation objects other than streams are ignored during simulation. Blocks and Streams can be deactivated and activated by clicking the right mouse button on the flowsheet object, and choosing Deactivate/Activate. Blocks and streams as well as other flowsheeting and analysis tools such as design specifications and sensitivity can be deactivated and activated from the navigation pane's right mouse button menu.
This feature can be used to focus on one unit operation when the rest of the flowsheet is not executed. Please follow the steps:
1. First run the simulation.
2. Deactivate all the blocks except the block of interest.
3. Click on the feed stream of this block and select “Reconcile”.
4. Reinitialize and Run the file.
Key-words
Multi block, Reconcile, Feed stream
Keywords: None
References: None |
Problem Statement: RGibbs reports this error:
** ERROR WHILE EXECUTING UNIT OPERATIONS BLOCK: B5-1 (MODEL: RGIBBS)
(GIBBS.19)
UNABLE TO BALANCE ATOM S (or other atom) in RGibbs block
Cause
This occurs in a number of situations where RGibbs cannot satisfy the mass balance according to the specified restrictions.
This can occur if you Identify Possible Products on the Setup | Products sheet, but there is no combination of the specified products which can satisfy the feed. For instance, if there is an atom in the feed but not in any of the products, then RGibbs will not be able to satisfy the balance for that atom.
It is also possible to have a specification that works for some but not all feeds, for example, if you have CH4 and O2 entering, but you specify only CH4, CO, CO2, and H2O can be products. If there is excess O2, RGibbs will have nowhere to put it after producing as much CO2 and H2O as possible.
This can also occur when you specify product flow rate or fraction for a component on the Setup | Inerts sheet in such a way that you force some or all of the component to react, but there are no suitable reaction products.
It is also possible that a combination of these two types of restrictions makes the problem infeasible.
In V8.4 and higher there will be a warning message when this situation occurs. | Solution: Compare the product restrictions with possible reactions and the feed composition and ensure there is some combination of products which satisfies the mass balance and the product restrictions. You may need to remove restrictions, modify specified product flows or fractions, or add additional compounds as allowed products.
Keywords: None
References: None |
Problem Statement: What is the difference between KLL and TXX or TPXX mixture data types for data regression of liquid-liquid equilibrium data. What is the definition of KLL? Why do I have to enter KLL, since it can be calculated from the first and second liquid phase compositions? | Solution: The data types are very similar.
The KLL data type expects the user to enter KLL = X2 / X1.
As to redundancy of data, while it is true, by explicitly entering KLL data, these data will be included in the objective function and new constraints will be added. This can alter the regression results. Basically, when you enter only TPXX data, the isofugacity criteria is being enforced. By entering KLL data, the program will try to minimize the difference of the experimental and calculated distribution coefficients. It can give you a little better control. It is not expected to give vastly different results.
An example to illustrate the two data types with made-up experimental values is attached. You can see that the regression results are very similar.
Please note that it is very important for liquid-liquid experimental data that the composition for both liquid phases are entered on the experimental data. The graphical user interface allows you to leave missing values (blank) like for liquid-vapour experimental data (where one phase may not have been measured). Missing composition can be estimated automatically by Aspen Plus for VLE, but for LLE this does not work. If for LLE the composition of one phase is missing, the suggestion is to guess it yourself using some plotting, possibly giving a larger standard deviation to those points. Otherwise, the data regression case will fail to converge.
We will add this information in the product documentation in a future version.
Keywords: CQ00459116
References: None |
Problem Statement: When performing consistency tests, the results show either failed or not performed. What is the cause of this? | Solution: The Aspen Physical Property System tests the binary vapor-liquid equilibrium (VLE) data for thermodynamic consistency only when both of the following conditions are satisfied:
1. Composition data for both the liquid and vapor phases.
2. At least five data points, not counting pure component data points (x=0.0 and x=1.0).
If one of the previous conditions is not satisfied the Aspen Physical Property System cannot carry on with the consistency test.
The test can fail because:
A? The data contains errors, either in the original data or occurring during data entry.
A? The vapor phase equation-of-state model does not appropriately account for the vapor phase nonideality.
A? You do not have enough data points or the data cover only a small concentration range. To obtain meaningful consistency test results, enter data for the entire valid composition range.
If the data fail the test, check the data values and units in the Txy, Pxy, or TPxy data entered on the Data Mixture form. If the system contains components that are highly unideal, such as organic acid, make sure that appropriate vapor phase equation of state model is used in the selected property method. For these systems, the Hayden-O'connell or Nothnagel model are recommended. Please be aware that failed data can cause accuracy and convergence problems in your calculation.
Keywords: data regression, consistency test, test failed, test not performed
References: None |
Problem Statement: How can I include multiple parts and unit models within a Hierarchy User Model block in Aspen Plus? | Solution: In order to include multiple parts and unit models within a Hierarchy User model block in Aspen Plus. The below procedure will help:
1. Select with the mouse the streams and unit models that you want to move to the hierarchy:
2. Then, right-click on the selected items and select ‘Move Selection':
3. Select the option ‘Create new hierarchy' or ‘Move to hierarchy’ (in case that you have a hierarchy block already created ):
4. Now all these items will be included under this hierarchy block:
5. If you also select the box named ‘Show advanced selection dialog', you can also select from the entire list what do you want to move in specific in terms of unit blocks and streams among others properties as shown below:
Keywords: Hierarchical Model Block, Move Selection Option, Create or Move Hierarchy Block.
References: None |
Problem Statement: When one makes a property set for GMTRUE (called property set A), which is the activity coefficient of a true species in a mixture, and a separate property set for MTRUE (called property set M), one may specify them using the Stream-Prop variable under | Solution: When referring to a Prop-set variable, it is not possible for this particular case to access the definition inside this. Hence, it has to always be the first variable defined in the Prop-set. In other words, the first value of the Prop-set. E.g.: If in the qualifiers tab for Prop-set A, if you defined components O2, H2, H2O, you are referring to the component O2. If no qualifier is defined, it refers to the first component defined in components definition table.
Keywords: GMTRUE, MTRUE, Prop-Set, True Species, Electrolyte Properties.
References: | Prop Set in a Flowsheet Option or a Model Analysis Tool. However, when specifying these Stream Prop variables does not show the option to select which component one wants to get GMTRUE and MTRUE for. |
Problem Statement: VBA and VB.NET example: Creating a new simulation from the ground up through COM Automation. | Solution: This attached example in VB.NET and VBA illustrates how to set up a simple simulation from the ground up through ActiveX interfaces in Aspen Plus.
The code will allow to:
- Create a new simulation
- Entering components and selecting the property method
- Create streams and a heater block
- Attach the streams to the block ports
- Entering stream specifications and block operating conditions
- Run simulation
Keywords: Aspen Plus interfaces example. ActiveX, Automation, VBA, VB.NET
References: None |
Problem Statement: How do you write Fortran expressions? | Solution: We are adding a new help topic with some simple instructions on how to use Fortran since so many new engineers have no experience with it. It is important to note that Fortran expressions are used not only in the Calculator block, but on other forms such as Design specification and Sensitivity. Also, basic Fortran is no more complicated than writing an equation in Excel.
How to Write Fortran Expressions
Not sure how to use Fortran? This topic explains the basics of writing code to perform simple calculations in Fortran.
Fortran used in Aspen Plus is limited to Fortran 77 syntax, which the following sections describe. Fortran variable names and function names are not case sensitive; PRES, Pres, and pres all refer to the same variable.
All of the syntax described on this page can be interpreted, which means that you do not need to have a Fortran compiler installed to use it. Some other Fortran statements can also be interpreted; for a full list, see About the Interpreter.
Assignments and Arithmetic Operators
The most commonly used Fortran statements are assignment statements, which have the form
variable = Fortran expression
The variable can be one you have defined as a variable in a Calculator block, or one defined in a declaration statement. The Fortran expression can be a number, another variable, a function call, or an arithmetic operation combining two or more expressions of these types. The value resulting from evaluating the Fortran expression is assigned to the variable when this statement is executed. In some cases in Aspen Plus, such as the Spec, Target, and Tolerance of a Design-Spec and the limits on manipulated variables, you will enter only a Fortran expression. In this case, there is an implicit assignment to the indicated attribute (in the same way that you would simply enter a number in most fields), but the expression is evaluated each time the value of the attribute is required.
The basic arithmetic operators are:
Addition
The + sign is used for addition. The following statement adds 1 to the value of B and assigns the result to A:
A = B + 1
Subtraction
The - sign (ASCII hyphen, not an em dash or en dash character) is used for subtraction. The following statement subtracts 1 from the value of B and assigns the result to A:
A = B - 1
Multiplication
The * character (asterisk) is used to represent multiplication. The following statement multiplies the value of B by 2 and assigns the result to A:
A = B * 2
Division
The / character (slash) is used to represent division. The following statement divides the value of B by 2 and assigns the result to A.
A = B / 2
Note: Division of one integer-type variable by another is integer division: the numbers are divided, the whole part of the result is kept (as an integer-type value), and the remainder is ignored.
Exponentiation
Two asterisks ( ** ) are used to represent exponentiation. Keep in mind the standard mathematical restrictions on exponentiation. The following statement squares the value of B and assigns the result to A:
A = B ** 2
Order of Operations
You can combine multiple arithmetic operations into a single expression. When you do so, Fortran has a specific order in which it performs the operations:
· Exponentiations are performed first, right to left.
· Multiplications and divisions are performed next, left to right.
· Addition and subtraction is performed last, left to right.
For example, 2+5*3 evaluates to 17 because the product 5*3 is calculated first, and then 2 is added to it.
You can group expressions in parentheses to specify a different order of calculations. Everything in parentheses is evaluated before anything outside the parentheses. If parentheses are nested, operations inside the inner parentheses are performed before those in the outer parentheses. For example, (2+5)*3 evaluates to 21.
Comments, Line Numbers, Continuation, and Indentation
You may notice how the examples in this topic are all indented. In Fortran statements, the first 6 columns are special.
· A comment line, which is ignored during calculations, can be indicated by placing a C or c in the first column.
· Line numbers can be indicated by writing the numbers into the third, fourth, and/or fifth columns. These can be used in certain kinds of statements to refer to another line. In lines which are neither comments nor numbered, you should leave the first five columns blank (spaces).
· The sixth column is used only for the continuation character, to indicate that the line is a continuation of the previous line when expressions are very long. Fortran lines must not be longer than 72 characters, including the initial 6 spaces. Any character other than a space in the sixth column will make the line a continuation, but it is traditional to use a plus sign or to use digits (2 for the second line, 3 for the third line, and so forth).
The built-in editor in the Calculator | Input | Calculate sheet automatically leaves 6 blank spaces at the start of each line. If you need to make comments, line numbers, or continuations, you can delete these spaces.
Variable Types and Declarations
Fortran variables have explicit types indicating the kind of data they can hold. The most common variable types found in Fortran used within Aspen Plus are:
· Integer: A variable that holds a whole number such as 0, 1, or -2. Integers are stored in 4 bytes or 32 bits, one of which is used to store the sign, so they can hold values between 231 and -(231), or about 2,000,000,000 and -2,000,000,000. Note, though, that you cannot enter commas when writing large numbers into your Fortran program; just write 10000 instead of 10,000.
· Real*8: A real variable which can hold a whole or fractional (decimal) value. The *8 indicates that the variable uses 8 bytes or 64 bits. This kind of variable (also called double precision) can store about 14 digits of accuracy and can store numbers up to about 10308 or as small as 10-308, as well as the negatives of this range. When you enter decimal numbers directly into your Fortran program, be sure to use a period or full-stop ( . ) as the decimal separator, even if Aspen Plus is configured to use a comma for the decimal separator elsewhere. For example, 1.5 is the correct way to write the number one-and-a-half.
Two less commonly used types are:
· Character*n: A character variable can store a string of text. The n indicates the maximum length of the string which the variable can hold.
· Logical: A variable which can store a true or false value. If you want to write literal true and false values in your Fortran program, they have to be enclosed in period or full-stop characters (.TRUE. or .FALSE.). You can also generate Logical data as the result of using comparison operators.
When you perform arithmetic operations on two numbers, the result is the same type as the numbers you are operating on. If one number is real*8 and the other is integer, the result will be real*8.
Variables you define with a reference to an Aspen Plus variable are automatically declared with the type appropriate to the Aspen Plus variable. This is usually Real*8, but countable items such as stage numbers are of type Integer. If you want to make intermediate variables used during calculations, enter declarations for these variables in the Fortran Declarations dialog box of a Calculator block, or at the start of an external Fortran subroutine. Declarations consist of the variable type followed by the variable, separated by a space. You can declare multiple variables of the same type by separating them with commas. To declare an array variable, enter the dimensions in parentheses, with multiple dimensions separated by commas, after the variable name in a declaration. Example declarations:
INTEGER I, J(2)
REAL*8 TIME,VOLUME,PRES(7,10)
LOGICAL C
CHARACTER*10 NAME
A Fortran variable name must:
Be eight characters or less
Start with an alphabetic character (A – Z)
Have subsequent alphanumeric characters (A – Z, 0 – 9)
Not begin with IZ or ZZ
Conditions and Branching
You can write IF statements to perform certain operations only in certain conditions. The format of an IF statement is:
IF (logical expression) THEN
conditional code
END IF
The logical expression can be a logical variable or the result of a comparison or logical operator. The parentheses around the logical expression are required. If the logical expression evaluates to true, then the conditional code is executed, and otherwise it is skipped.
Comparison Operators
Comparison operators can be used in decision statements, or to store a value in a logical variable which may be used in a decision statement later. The comparison operators in Fortran are:
Operator
Meaning
.LT.
Less than
.GT.
Greater than
.EQ.
Equal
.LE.
Less than or equal
.GE.
Greater than or equal
.NE.
Not equal
For example, the expression B .LT. 3 is true if B is less than 3.
Logical Operators
For complicated logical expressions you can use logical operators to combine multiple logical expressions. The logical operators in Fortran are:
Operator
Meaning
.AND.
And (true only if both expressions are true)
.OR.
Or (true if either or both expressions are true)
.NOT.
Not (reverses result of following logical expression)
For example, the expression A.EQ.3 .OR. B.LT.2 is true whenever A equals 3, B is less than 2, or both.
You can use parentheses to group parts of expressions involving comparison and logical operators. All arithmetic operations are performed first, then comparisons, and logical operators are last, with .NOT. evaluated before .AND., then .OR. is evaluated last.
Function Calls
You can call functions by typing the function name followed by its arguments in parentheses. If the function takes more than one argument, separate the arguments with commas ( , ).
Most commonly you will call the following built-in Fortran functions (the ones beginning with D return a double precision or real*8 result, while the others return an integer result):
Function
Meaning
DABS(X), IABS(J)
Absolute value
DSIN(X), DCOS(X), DTAN(X)
Sine, cosine, and tangent functions of X in radians.
DASIN(X), DACOS(X), DATAN(X)
Inverse sine, cosine, and tangent functions, with the result returned in radians.
DEXP(X)
Exponential function (ex)
DLOG(X)
Natural logarithm of X
DLOG10(X)
Base 10 logarithm of X
DSQRT(X)
Square root of X
DMIN1(X1,X2,...), DMAX1(...)
Minimum and maximum of the arguments (two or more real*8 arguments)
MIN0(J1,J2,...), MAX0(...)
Minimum and maximum of the arguments (two or more integer arguments)
DFLOAT(J)
Converts an integer value to a real*8 value
IDINT(X)
Converts a real value to an integer, truncating the fractional part. IDINT(1.3)=1; IDINT(-2.7)=-2.
Keywords: None
References: None |
Problem Statement: How can I check the results of the downcomer geometry of a RadFrac column? | Solution: When the user does not specify any information about the downcomer geometry (widths/weir lengths), it is possible to check the dimensions considered by Aspen Plus in the Report of the RadFrac column. To do so, the user needs to run the model, then click on the Report option in the Home ribbon:
Then, select the column block and the report will be opened using the Notepad application. Once the text file is opened, scroll down until locating the title DOWNCOMER DIMENSIONS as it is shown in the screenshot below:
Keywords: Downcomer results, downcomer clearance results, weir height results
References: None |
Problem Statement: When modelling a process in Aspen Plus, is it possible to transfer the flowsheet (streams, unit operations) to a PDF file format.
I am using PDF-XChange 4.0 writer, but sometimes some unit operation symbols are not displayed in the PDF file. | Solution: There is another software which is called XPS Document Writer, that allows the user to create a file with the flowsheet drawing. This software belongs to Microsoft, so it is installed by default when using this operating system.
To “print” the flowsheet as a document, go to File | Print and select from the drop list: Microsoft XPS Document Writer. The XPS file will be created.
The last step will be to convert the XPS file to a PDF file, but this requires another part of the software (obtainable from the link below)
XPS to pdf
The file obtained in PDF from a XPS file is attached to theSolution.
Keywords: Flowsheet, XPS, pdf format
References: None |
Problem Statement: Could not start Aspen InfoPlus21 database with error - Not enough space for nnnn word database | Solution: This KB article describes steps to follow in case the Aspen InfoPlus21 database could not be started post upgrading the snapshot. And the error says - Not enough space for nnnn word database
1. Double click on the TSK_DBCLOCK task in the Defined task list (left hand side top section) in IP21 manager.
2. In the command line parameter (right hand side bottom), increase the number to the no. nnnn specifies.
Example: Not enough space for 3850000 word database. In this case, the command line has to be increased to 3850000.
Whatever the number is, this is the number of words of memory to be allocated when the tasks starts. Then LOADDB loads the snapshot into that amount of memory. (You may actually see DOUBLE in the command line parameters. The DOUBLE is used to allocate twice the amount of memory. This extra amount of memory is used for snapshot saves.)
3. Click Update.
4. Start InfoPlus 21 database from IP21 Manager.
5. This will increase the allowed number of words in database to specified value and will not complain about space anymore.
Keywords: Not enough space
IP21 database
IP21 Manager
Database shutdown
References: None |
Problem Statement: How do you report a ratio of selected components in a Prop-Set? | Solution: In the attached file (built in Aspen Plus V8), the total light gas composition is calculated by summing the mass compositions of hydrogen, nitrogen, and methane and reporting it as a single value in the stream summary results.
To report a summation of component fractions:
1. Navigate to the Properties Prop-Sets folder within the Data browser. Click the New... button and provide a unique name, i.e., PS-1.
2. From the Physical properties drop-down list, choose the property RAT-MLFR for a ratio of mole fractions, RAT-MSFR for a ratio of mass fractions, and/or RAT-VLFR for a ratio of liquid volume fractions. Alternatively, you can click on the Search button and search for ratio. In this example, RAT-MSFR was selected for a ratio mass fractions.
3. On the Qualifiers tab, choose the components you want included in the ratio. After you add the first component, Aspen Plus will add a column to the right from which you can choose the second component, and so on. The Components are the components in the numerator of the ratio. The base components are the components in the denominator. In this example, there is a ratio of the mass fractions of the light components HYDROGEN, NITROGEN, and METHANE to the heavy components CHEXANE and BENZENE. This is
[ W(HYDROGEN) + W(NITROGEN) + W(METHANE) ] / [ W(CHEXANE) + W(BENZENE) ]
4. To report this parameter in the Streams report, navigate to the Setup Report Options form and click the Property Sets button on the Streams sheet. Move PS-1 to the Selected property sets area. The value is reported at the very bottom of the Results Summary Streams form.
You can also use this Prop-set in a Sensitivity analysis, Design Spec, or Calculator block.
Keywords: Properties, Prop-Set, parameters
References: None |
Problem Statement: How is vapor pressure PL calculated in an Analysis table when using an equation of state (EOS) property method? | Solution: In version 2006 and higher, it is possible to choose PL in the Tools -> Analysis -> Property -> Pure dialog for an equation of state property method. Before V8.0, PL tabulates vapor pressure as calculated from the Antoine coefficients for the component not from the equation of state used. Note that this only affects the Property Set property (mainly used for calculations such as property analysis), not simulation results.
In V8.0 and higher, the equation of state in a bubble point flash is used to calculate PL in Pure Analysis or in a Property Set. This means that the value of PL will vary with different equation of state property methods. Most Activity Coefficient methods use Antoine (PLXANT) to calculate PL so activity coefficient methods should all give the same vapor pressure results. Now the PL calculation will match the simulation results of a pure component.
Keywords: None
References: : CQ00563032 |
Problem Statement: When should I connect a heat stream on the HXFLUX block? | Solution: It is optional to connect a heat stream to HXFLUX; therefore, you may do as you see fit. Note that if you connect a heat stream as input, you must also connect a heat stream as output. If you connect a heat stream as output, you must also connect a heat stream as input. You may connect only up to one heat stream as input, and only up to one heat stream as output. The Next button will guide you in the completion of the flowsheet connectivity.
The HXFLUX block will automatically set the connected input stream as the heat duty specification (and therefore the heat duty or heat stream specification in the Block input data will be disabled since the duty is already specified).
See the attached simulation file for Aspen Plus V8.8 which demonstrates both configurations:
· heat stream reference in HXFLUX block
· heat streams connected as input and output of HXFLUX block
The results are identical. The first configuration has the advantage of using only one heat stream. The second configuration makes it more clear that the HXFLUX block is used to constraint the heat duty of heat stream. Note that in all cases you may have also to use Spec Groups and/or User Connections in the EO Configuration form to complete the heat integration constraints for the equation oriented model.
Keywords: HXFLUX, LMTD, Heat stream
References: None |
Problem Statement: What are the Typical Values of Overall Heat Transfer Coefficients? | Solution: The following values based on heuristics are proposed for short-cut design methods of heat exchangers. The upper values are good for particularly favorable conditions such as high flow velocities, thin fluid layers, optimum mass flow ratios, and clean surfaces. The lower values are recommended for particularly unfavorable conditions such as low flow velocities, viscous liquids, free convection, and fouling. These values can be entered in Aspen Plus on the HeatX | Setup | U Methods sheet.
The heat exchanger designer must take into consideration that the given values do not take additional heat conduction resistances of insulation and/or protective coatings.
“U” Value (W m-2 K-1)
Conditions of heat transfer
Type of exchanger
5-35
Gas (circa 101325 Pa) on tube side and gas (circa 101325 Pa) on
shell side
Shell-and-tube heat exchanger
150-500
High-pressure gas (20000–30000 KPa) on shell side
and high-pressure gas (20000–30000 KPa) on tube side
15-70
Liquid on shell side (tube side) and gas (1 bar)
on tube side (shell side)
200-400
High-pressure gas (20000–30000 KPa) on tube side
and liquid on shell side
150-1200
Liquid on shell and tube sides
300-1200
Heating steam on shell side and liquid on tube
side
See below for use as evaporator or condenser
Heating steam outside the tubes
Evaporator
1. With natural circulation
300–900
(a) Viscous liquids
600–1,700
(b) Low viscosity liquids
900–3,000
2. With forced circulation
200–800
Brine-heated ammonia evaporator
300–1,200
Cooling water on tube side and organic vapors or
ammonia on shell side
Condenser
1,500–4,000
Steam-turbine condenser (pure steam; thin brass
tubes) “U” decreases with an increase in the inert
gas fraction
15-50
Hot gas on tube side and boiling water on shell
side
Waste Heat Boiler
“U” Value (W m-2 K-1)
Conditions of heat transfer
Type of exchanger
Steam or hot water on (finned) tube side and gas
outside finned tubes
Gas Heater
5–12
(a) Free convection (heater)
12–50
(b) Forced flow
10–35
Gas (circa 101325 Pa) on tube side and gas (circa 101325 Pa) on
shell side
Double-pipe heat exchanger
20–60
High-pressure gas (20000–30000 KPa) on tube side
and gas (circa 101325 Pa) on shell side
150–500
High-pressure gas (20000–30000 KPa) on tube side
and high-pressure gas (20000–30000 KPa) on shell side
200–600
High-pressure gas (20000–30000 KPa) on tube side
and liquid on shell side
300–1,400
Liquid on shell and tube sides
20–60
Cooling water on shell side and gas (circa 101325 Pa) on
tube side
Falling-film cooler
150–350
Cooling water on shell side and high-pressure
gas (20000–30000 KPa) on tube side
300–900
Cooling water on shell side and liquid on tube
side
300–1,200
Falling-film condenser, e.g., for refrigerants:
cooling water outside and condensing vapor
inside tubes
20–60
Cooling water or brine outside and gas (circa 101325 Pa)
inside the coils
Helical coil heat exchanger
150–500
Cooling water outside and high-pressure gas
(20000–30000 KPa) inside the coils
200–700
Cooling water or brine outside and liquid inside
the coils
350–900
Cooling water or brine outside and condensing
vapor inside the coils
20–60
Flat channels, gas to water
Plate heat exchanger
350–1,200
Flat channels, liquid to water
1,000–4,000
Corrugated plates, liquid to liquid
“U” Value (W m-2 K-1)
Conditions of heat transfer
Type of exchanger
Compartmental heat exchanger
10–35
Gas to Gas at 101325 Pa
20–60
Gas to liquid
(A) Outer shell
Stirred tank
500–1,500
Condensing vapor outside and liquid inside the
tank
700–1,700
Condensing vapor outside and boiling liquid
inside the tank
150–350
Cooling water or brine outside and liquid inside
the tank
(B) Inner coil
700–2,500
Condensing vapor inside the coils and liquid
inside the tank
1,200–3,500
Condensing vapor inside the coils and boiling
liquid inside the tank
500–1,200
Cooling water or brine inside the coils and liquid
inside the tank
(C) Outer tube welded onto shell
500–1,700
Condensing vapor inside the heating channels
and liquid inside the tank
700–2,300
Condensing vapor inside the heating channels
and boiling liquid inside the tank
350–900
Cooling water or brine inside the cooling
channels and liquid inside the tank
Spiral plate heat exchanger
700–2,500
Liquid to liquid
900–3,500
Condensing vapor to liquid
Keywords: Overall Heat Transfer Coefficient
Shell-and-tube
Evaporator
Condenser
Waste-heat boiler
Gas heater
Double-pipe heat exchanger
Falling-film cooler
Helical coil heat exchanger
Plate heat exchanger
Compartmental heat exchanger
Spiral plate heat exchanger
Stirred tank
References: s:
Wilfried R. Bernhard S., Typische Werte des Wärmedurchgangskoeffizienten, VDI e.V. VDI-Wärmeatlas , DOI 10.1007/978-3-642-19981-3_12, Springer-Verlag Berlin Heidelberg 2013 |
Problem Statement: How to obtain results for user defined compounds VLE binary interaction properties using UNIF-DMD property method? | Solution: In order to obtain results for user defined compounds VLE properties using UNIF-DMD property method:
1) Run the attached example .aprbkp simulation file and some errors will be shown in the Control Panel:
2) Go to Components | Molecular Structure | B and C | Functional Group (tab), change the Method to UNIFAC and under the Structure (tab) click on Calculate Bonds:
3) Reinitialize the simulation to purge the previous results and re-run it.
4) Now the binary results plots for those components, as well as the table results are shown:
5) If you want now calculate the properties using UNIF-DMD, now you can select this property package from the Methods | Specifications | Global (Tab) under ‘Method name’, reinitialize and re-run the simulation once again.
Keywords: UNIF-DMD Method, VLE, User Defined Compounds.
References: None |
Problem Statement: How to display stream property on Flowsheet other than temperature, pressure & flow. | Solution: From Aspen Plus V8 onwards any stream property can be displayed on the Flowsheet in addition to the standard options from earlier releases.
Click on Stream Results as per below image:
Activate label & write label name which you want to display then select stream property from Prop-Set drop down menu as per below image:
Click on the Apply tab.
Keywords: stream property display, property display on flowsheet etc;
References: None |
Problem Statement: Uninstalling one version of Aspen Plus removes all of the Aspen Plus shortcuts for the other versions that are still installed. | Solution: When you uninstall a newer version of Aspen Plus (including beta versions), the shortcuts for the previous version get broken (e.g., “open with Aspen Plus V8x”). Running the Set Version utility found in the Start Menu in the AspenTech -> Process Modeling V8.x -> Aspen Plus folder will restore the shortcuts. This is also true for Aspen HYSYS and other products. Administrative rights are needed to run the Set Version Utility (and for uninstalling).
Keywords: shortcuts
un-install
References: : CQ00694766 |
Problem Statement: If I want to restore a database created in a specific server version using Aspen Properties Database Manager (APED). How can I determine the Microsoft SQL Server version installed on my computer? | Solution: The way to find out the version of an SQL server instance is from Registry. Each SQL instance has a unique name that will be used by APED. On 64-bit machine, you can look at this key for all 64-bit SQL server versions:
1) Go to Start and type ‘regedit’ at the ‘Search programs and files’ command line.
2) Go to the registry key “HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Microsoft SQL Server\Instance Names\SQL”:
3) For example, you may see two instances such asSQL08X64 and SQL12X64. From their data, you can tell that:
SQL08X64=MSSQL10_50.SQL08X64: MSSQL10 indicates that SQL08X64 is an instance of SQL server 2008 because 10 is the internal version number used for SQL server 2008 by Microsoft.
SQL12X64=MSSQL11.SQL12X64: MSSQL11 indicates that SQL12X64 is an instance of SQL server 2012 because 11 is the internal version number used for SQL server 2012 by Microsoft.
4) For all 32-bit versions, you can look at the following key “HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Microsoft\Microsoft SQL Server\Instance Names\SQL”:
SQLEXPRESS=MSSQL.1
SQL08X32=MSSQL10_50.SQL08X32
SQL12X32=MSSQL11.SQL12X32
5) Here you can tell that there are three SQL server instances:
SQLEXPRESS=MSSQL.1: This is an instance of SQL server 2005. MSSQL does not have a number such as 10 or 11.
SQL08X32=MSSQL10_50.SQL08X32: MSSQL10 indicates that SQL08X32 is an instance of SQL server 2008 because 10 is the internal version number used for SQL server 2008 by Microsoft.
SQL12X32=MSSQL11.SQL12X32: MSSQL11 indicates that SQL12X32 is an instance of SQL server 2012 because 11 is the internal version number used for SQL server 2012 by Microsoft.
Keywords: Microsoft SQL Server, APED.
References: None |
Problem Statement: When estimating properties, there are warning and error messages that are generated when running the case file. Why does this happen? | Solution: When we select “estimate all missing parameters”, our Property Constant Estimation System (PCES) will attempt to generate the functional groups for the corresponding estimation methods to be used. If no specific method was selected for a certain property, our system will go through the estimation methods available in the same order displayed in the drop down menu. When it can’t describe a certain molecule in one of the methods, it will record a warning and move to the following method. These warnings can be ignored unless a preferred estimation method was the one that failed.
If we get the following warning:
STRUCTURE FOR COMPONENT ACETIC HAS NOT BEEN DEFINED.
PCES CANNOT USE GROUP-CONTRIBUTION METHODS TO ESTIMATE MISSING PROPERTIES
USE THE STRUCTURES PARAGRAPH TO DEFINE STRUCTURES OF THIS COMPONENT.
This is because the structure for that component has not been defined. In order to estimate parameters you need to provide at least the molecular structure (and in most cases also the normal boiling point (TB)). In order to introduce the structure, do the following:Solution 141283 describes how to use mol files to define the structure when it is not available in the Aspen Plus databanks
http://support.aspentech.com/webteamcgi/SolutionDisplay_view.cgi?key=141283
Normally we perform an estimation run for the parameters we want to obtain, and afterwards we de-select estimation as shown below. This way the warnings won’t show up in future runs, but the parameters estimated will still be available.
Keywords: Estimation parameters, warnings, PCES, functional groups.
References: None |
Problem Statement: How does Aspen Plus calculates MTRUE (molality) and activity coefficient of true species in a mixture on molality basis (GMTRUE)? | Solution: RelatedSolution 103517
The activity of true species on a molality scale is given by:
a(ionic species) = xm(ionic species) * gamma(ionic species)
in which:
a(ionic species) is the activity of true species on molality basis
xm (ionic species)=: molality of ionic species
gamma (ionic species)= activity coefficient on a molality basis
Molalities can be reported in Aspen Plus using the Prop-Set property MTRUE and activity coefficients on a molality basis can be reported using the Prop-Set GMTRUE.
MTRUE and GMTRUE are calculated as follows:
molality=(molar flow of ionic species /mass flow of water)*1000
GMTRUE=[(ionic mole fraction*ionic activity (gamma)*1000/18]/ionic molality
View the Physical Properties Method documentation from the support website. The following screen shot is from page 191 of this documentation (V8.4).
Keywords: MTRUE, GMTRUE
References: None |
Problem Statement: When creating SQLADef tags, users might want to set the value of the IP_STEPPED field to either Interpolated or Stepped to use this setting as a default for Process Explorer (checked on unchecked Stepped column). However, in order to accomplish this task, the map record for SQLA tags (IP_SQLAMap) must be modified. | Solution: To modify the SQLA map record, follow these simple steps:
1. Locate IP_SQLAMap, defined by AtMapDef.
2. Set the filed MAP_#Maps to 1 to add an occurrence.
3. Go to the first occurrence and add 'STEPPED' to Map_Attribute and 'IP_STEPPED' to MAP_FieldName. This step allows IP_SQLAMap to match the IP_AnalogMap record and Process Explorer to default to the value specified by IP_STEPPED.
4. Go the IP_SQLADef tag and set IP_STEPPED to either 'Stepped' or 'Interpolated'
5. Now the default setting can be seen in Process Explorer.
Keywords: SQLA
Stepped
IP_STEPPED
References: None |
Problem Statement: 왜 rate-based distillation column 플래시계산에서 온도가 서로 다른가? | Solution: Rate-based stage에서 증기성분과 액상성분은 상평형을 이루지 않는다. 기액상평은 오직 경계면에서만 발생한다고 가정하기에 이를 화학평형으로 볼 수 있다. 때문에 rate-based stage에서는 플래시 온도가 다를 수 밖에 없고 출구유체에서 기액상평형과 화학평형을 이루어질 수 없다.
Keywords: None
References: : CQ00357921
Please find |
Problem Statement: If I have to repair file sets from many repositories, can I run multiple copies of H21ArcckWizard.exe (History Arc Check Wizard) at the same time? | Solution: If you have to repair file sets from multiple repositories, you can start concurrent copies of the history archive checking wizard (H21ArcckWizard).
Keywords: repair file set
References: None |
Problem Statement: Listed here are the two most likely occasions when you might see the error:
Licensed Point Count must be 'nnnnnn' Minimum
(where 'nnnnnn' might be any number between 1 and 2097151)
You might see this in the Output file for Loaddb when the Aspen InfoPlus.21 startup fails at loaddb.
Another time might be when trying to create a new tag, a record which has one or more History Repeat areas. | Solution: Shutdown the Aspen InfoPlus.21 database if it is currently running - the problem cannot be solved with it running.
From the Left hand pane of the Aspen InfoPlus.21 Administrator, under InfoPlus.21, right click on the name corresponding to the database in question.
Choose Set Point Count
It is the number seen here that needs to be changed to a value at least as large as the number in the error message.
Note - typically, you would set this value to the number of licensed points that you purchased for this system. That is why you will only see the problem when trying to use more 'tag' records than the defined setting.
Keywords: None
References: None |
Problem Statement: How do I check the license status on my Aspen InfoPlus.21 server? | Solution: The License Status tab displays the current status of the InfoPlus.21 server.
To view license information:
1. In the InfoPlus.21 Administrator, right-click the InfoPlus.21 database and select Properties from the context menu.
2. On the Database Properties dialog box, click the License Status tab. The following license status information is displayed.
· License State - Displays one of the following:
— License Granted – The license server confirms the checkout of the requested license units.
— License Timeout – The license has been granted but InfoPlus.21 is no longer able to contact the license server. If contact with the license server is not restored, then the License Timeout period can last for a timeout period specified in the license key. The default timeout period is 900 minutes (15 hours).
— License Grace Period – The license has been granted at least once, the license server cannot be contacted and the license timeout, if any, has elapsed.
— License Denied – Either the license server denies the request checkout or the license server cannot be contacted and the license grace period, if any, has elapsed.
· State Transition Time - The start time of the current state.
3. If in License Denied mode, the Details button is available. Click Details to view more information about why the license was denied.
For additional information on License State and functionality, visit knowledge base article 139153.
Keywords: License Status, InfoPlus.21, IP.21
References: None |
Problem Statement: How does Aspen InfoPlus.21 use the field FIELD_NUMBER (hex) in records defined by FieldNameDef and FieldLongNameDef? | Solution: Aspen InfoPlus.21 uses records defined against FieldNameDef and FieldLongNameDef to create data field names for Aspen InfoPlus.21 records. The only difference between data field names defined against FieldNameDef and FieldLongNameDef is the maximum length of the data field names defined against them. Data field names defined against FieldNameDef have a maximum length of 12 characters, while records defined against FieldLongNameDef can be used to create 20-character data field names.
Aspen InfoPlus.21 connects a record's data fields to data field names using the field FIELD_NUMBER (hex).
This 16-bit field number has two parts:
· Bits 15 to 10 contain a field check code (which is largely unused today)
· Bits 9 to 0 contain a field pointer
The bottom 10 bits (bits 9 to 0) are used to map a data field name to a data field number in a definition record.
As an example, the field number of IP_INPUT_VALUE is 7459 (hex). Masking off the bottom 10 bits gives 1011001 (binary) = 89 (decimal).
Using the Aspen InfoPlus.21 Administrator, expand IP_AnalogDef, the icon Fields, and finally the repeat area MAX_FIELD_POINTER
Find occurrence 89 and see the value in the field FIELD_NDX_vs_POINTER is 10. This means that IP_INPUT_VALUE is field number 10 in the definition record.
There are two implications with this structure:
· A definition record can have a maximum of 1024 data fields
· You cannot place data field names in the same definition record having the same values in the same bottom 10 bits. For example, you cannot put the following fields in the same definition record
o IP_TREND_VALUE [FIELD_NUMBER (hex) =2419]
o DISPLAY_LENGTH [FIELD_NUMBER (hex) =1019]
o MAX_NUM_POINTS [FIELD_NUMBER (hex) =7419]
o #TIME_STAMP_VALUES [FIELD_NUMBER (hex)=2419]
o #SUMMARY_DESCS [FIELD_NUMBER (hex)=1419]
o ACTUAL_VALUE_FLD [FIELD_NUMBER (hex)=2419]
o Q_CONDITION_TIME [FIELD_NUMBER (hex)=5019]
o IO_DEVICE [FIELD_NUMBER (hex)=4019]
o TREND VALUE [FIELD_NUMBER (hex)=2419]
Keywords:
References: None |
Problem Statement: How can I delete a file set to recover disk space without first stopping Aspen InfoPlus.21? | Solution: Aspen Technology strongly recommends stopping Aspen InfoPlus.21 before deleting the contents of file sets (arc.dat, arc.key, and arc.byte); however you can following these steps if it is not possible to stop Aspen InfoPlus.21.
1. Open the Aspen InfoPlus.21 Administrator and stop the repository with the file set to be deleted.
2. Right click over the fileset, select properties, uncheck the Mounted checkbox, and click on Apply and then Ok. The fileset status should change to None.
4. Using Windows Explorer, navigate to the folder containing the file set and remove the files arc.key, arc.dat, and arc.byte. (Don't delete the folder, just the files).
5. Go back to the Aspen InfoPlus.21 Administrator, right click over the repository node and select Start.
Keywords: Fileset
Repository
Delete
References: None |
Problem Statement: TSK_DBCLOCK hangs at 50% during startup, then quits. Error messages found in TSK_DBCLOCK are:
h21_arck_local failed with ret = -1040
CreateFile failed
The problem appears to be related to the history filesets. For V7.1 and later, a new utility exists that attempts to validate the path to each fileset. For history startup problems after a migration, it is a great tool to find problem filesets that may have corrupt data preventing a good startup (this tool is installed in V7.3 and later automatically. For Version 2006.5 and later the tool is added to a system by applying the latest InfoPlus.21 cumulative patch for that version.) However when running the tool under some circumstances, it stops and exits before starting to validate the individual filepaths, with a failure to read a cache file: | Solution: In this case customer had run h21chgpaths.exe to change the UNC path for all the filesets in config.dat. Since the directory structure was unchanged on the new server, the change of nodename in config.dat seemed to be enough. However in addition to the fileset locations, config.dat also specifies the repository backup path, and in this case, it was specified by drive letter on the old system, for example as:
E:\History\backup\
Re-running h21chgpaths.exe, changing all E:\ references to C:\, then making sure to create the actual backup folder along the correct path, resolved the problem. At that point ValidateArchive.exe ran successfully, and more importantly, the system started up without a hang of TSK_DBCLOCK.
Keywords: ERROR: Failed to check archives.
ERROR: Cannot open cache.dat file.
References: None |
Problem Statement: When using standard IP_AnalogDef records, normal behavior is that values written to the IP_INPUT_VALUE field will propagate to the IP_VALUE field, and then be written to history. You might see a situation where the values updating in IP_INPUT_VALUE do not propagate to IP_VALUE. | Solution: One possible cause of this behavior is that compression is activated for the record. If this is not the case then there could be a problem with the IP_BoxcarSlope record. The IP_BoxcarSlope record must be configured for data to propagate from IP_INPUT_VALUE to IP_VALUE even though compression is not being used. The IP_BoxcarSlope record should be configured like the following example.
Example IP_BoxCarSlope record defined by BoxCarSDef.
NAME
IP_BoxcarSlope
NEXT_PROCESS_RECORD
(empty field)
DEFAULT_BASE_RECORD
D-IP_Analog
LAST_RECORDING_FIELD
D-IP_Analog 1 IP_TREND_VALUE
SIGNIFICANCE_FIELD
D-IP_Analog IP_DC_SIGNIFICANCE
SIGNIFICANCE_VALUE
??????????????????????
MAX_INTERVAL_FIELD
D-IP_Analog IP_DC_MAX_TIME_INT
MAX_TIME_INTERVAL
+00000:00:00.0
UPDATE_TIME_FIELD
D-IP_Analog IP_INPUT_TIME
RECORDING_TIME_FIELD
D-IP_Analog 1 IP_TREND_TIME
STATUS_FIELD
D-IP_Analog IP_DC_STATUS
SLOPE_FIELD
D-IP_Analog IP_DC_SLOPE
LAST_UPDATE
18-AUG-00 16:29:12.7
BCS_STEPPED_FIELD
D-IP_Analog IP_stepped
Keywords: ip_input_value
ip_value
history
References: None |
Problem Statement: This knowledge base article explains how to remove duplicate tasks from the Aspen InfoPlus.21 Manager defined task list. | Solution: Duplicate tasks can appear in the Aspen InfoPlus.21 Manager task list when there is more than one task registered in the registry with the same order number. Try to remove the extra task using the 'Remove' button. If that does not work go to the following location in the registry:
32 bit systems :-
HKEY_LOCAL_MACHINE\Software\AspenTech\InfoPlus.21\<version number>\Group200\RegisteredTasks
64 bit systems :-
HKEY_LOCAL_MACHINE\Software\WOW6432NODE\AspenTech\InfoPlus.21\<version number>\Group200\RegisteredTasks
Edit the task that is duplicated and notice that the order number is the same as the order number of another task in the list. Check one by one through the other entries to find the task with the duplicate order number and change it to a non-existent number in the list. This order numbering is consecutive and must correspond with the order shown in the Aspen InfoPlus.21 Manager defined task list.
Keywords: Duplicate Defined tasks
IP.21
References: None |
Problem Statement: The example for INSOCCS in the manual is for inserting new occurrences into history. The following example shows how to do this for a non history occurrence such as ENG-UNITS. | Solution: NOTES: modify the #define for ARRSZ for the number of occurrences to insert, INSERT_AT for the occurrence number to begin inserting, the recid variable for ENG-UNITS on your system and the description array values for the actual units to write.
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <setcim.h>
#define TRUE 1
#define FALSE 0
#define NUMTAGS 1 /* Number of Fields to update in each occurrence inserted*/
#define ARRSZ 2 /* Number of occurrences to insert - modify as needed */
#define INSERT_AT 38 /* Insertion occurrence - modify as needed */
#define DBCHAR_8 8 /* Db data type of byte array 8 bytes long - for character type */
main()
{
long recid = 892; /* Record ID for ENG-UNITS record on test system */
long fts[NUMTAGS] = {0x10080000}; /* field tag of SELECT_DESCRIPTION field */
long ft = 0x10080001; /* field tag of 1 SELECT_DESCRIPTION field */
char description[ARRSZ][8] = { NewUnit, OldUnit }; /* new eng units to write */
long numoccs = ARRSZ,
occnum = INSERT_AT; /* First occurrence number to insert */
short i,
occsok,
occsinserted,
numfts = NUMTAGS,
ftsok,
datats[NUMTAGS] = { DBCHAR_8 },
*ptdatas[NUMTAGS] = { (short *)description },
error_len;
ERRARRAY error_msg;
ERRBLOCK err;
if ( INISETC())
{
for (i = 0; i <= NUMTAGS; i++)
{
printf (\nDescription to load is %s\n, description[i]);
}
INSOCCS(recid, ft, numfts, fts, datats, numoccs, occnum,
ptdatas, &occsinserted, &occsok, &ftsok, &err);
if (err.ERRCODE != SUCCESS)
{
ERRMESS(&err, error_msg, &error_len);
error_msg[error_len] = ''\0'';
printf(***Error: %d - %s...\n, err.ERRCODE, error_msg);
}
printf(\n\n%d occurrences inserted.\n,occsinserted);
printf(%d occurrences OK.\n,occsok);
printf(%d field tags OK.\n,ftsok);
}
else
{
printf(Database is not up...\n);
}
ENDSETC();
}
Keywords: INSOCCS
LOCAL API
code
References: None |
Problem Statement: Users who develop large custom applications which rely on Aspen Batch.21 data prefer to use the fastest method of data retrieval possible to optimize performance in their custom applications. This knowledge base article describes which method of data retrieval is faster. | Solution: Assuming the user interacts with the Aspen Batch.21 API and the web service identically the performance will be faster in the Aspen Batch.21 API as the web service is just an extremely thin wrapper around the API datasource's XML method. If the web service is used, the application will see the performance impact of the Aspen Batch.21 API plus the marshalling that occurs through http and the web service.
Keywords: None
References: None |
Problem Statement: What are Static-cell Constant or Static-cell volume used for ebulliometry data? | Solution: The Static-cell constant should be used when TPZ data type is used.
The Static-cell volume is used when TPF data type is used.
The value of static-cell constant or volume should be found in the user manual of the differential static-cell apparatus used for generating those TPZ/TPF data. This type of apparatus uses cells where liquids are injected for experimental purpose. The constants are associated with these cells and depends on different type of cells.
Keywords: regression, Static-cell Constant, Static-cell volume, TPZ, TPF
References: None |
Problem Statement: ?e`a电脑???L?{???s?????{Aspen Hysys软??时?C??么设?u?z?E???{?H | Solution: Aspen Hysys软???A?E调?pExcel automation work???I拟`S关?I?H?o?B ?v?Y电脑????时?A`????D?{???s?????{Aspen Hysys?C??么?K须??设?u?z?E???{?B???A?Iscript?????Y专门?p为???e?z?E???{?I?B
1. ??载RegHYSYS72.txt?????B
2. ?u??RegHYSYS72.tex?I扩?W??为RegHYSYS72.bat.
3. `o击该?????C?o???i删???????e?IAspen Hysys???{??时???ev7.2???{为?z?E???{?B
?v?Y`z???ev7.1???{?C?E`o击该?????@编辑script?A?s?C?a?@`u??v7.1???{script?B
?^Excel VBA`S关?IAspen Hysys type library?M`?请ZQ?lSolution ID 129694.
Please find theSolution 131162 for the original English version.
Keywords: Automation, Excel, Register, CN-
References: None |
Problem Statement: Does an Aspen Plus compound (.apwz) file contain an .apw file or a .bkp (backukp) file? | Solution: The compound (.apwz) file can contain either a .apw or .bkp file. It is selected on the File | Options | Files page. The default is .apw.
Keywords:
References: None |
Problem Statement: When should the water solubility option be changed? | Solution: Water Solubility method should be left at the default value of 3 except when modeling water-hydrocarbon systems where two liquid phases form and the aqueous phase is almost pure water, and is modeled using the Vapor-Liquid-Free Water or Liquid-Free Water valid phases options.
In V7.3.2 and higher, an information message has been added if the Water Solublity method is 0 and Free Water is not specified for the Valid Phases:
INFORMATION WHILE CHECKING INPUT SPECIFICATIONS
BLOCK NAME: (name) MODEL NAME: (name)
THE WATER SOLUBILITY OPTION HAS BEEN CHANGED TO 0.
THE WATER VAPOR FUGACITY WILL BE CALCULATED BY THE FREE-WATER METHOD.
Keywords: None
References: : CQ00414987 |
Problem Statement: Running a simple steam turbine calculation works fine with STEAMNBS, but fails with IAPWS-95 producing the following error message:
***SEVERE ERROR
CANNOT FIND TEMP FOR ISENTROPIC COMPRESSOR/TURBINE.
ERROR IN ENTROPY = -0.11711E+07 | Solution: When using a COMPR model as a Turbine and IAPWS95. If the conditions are above the supercritical region, the IAPWS95 will return single density for both so called vapor and liquid phases. With the same density Aspen Plus will return same fugacity for both phases, thus the simulation does not converge properly.
An alternative way to continue use IAPWS95 is to change fugacity route so that the fugacity calculated is done by STMNBS model, while IAPWS95 is still used for other properties such as density, enthalpy, etc. To do that under Properties Environment, you can go to Properties | Property Methods | IAPWS-95 | Routes, then change PHIVMX from PHVMWS95 to PHIVMX90, change PHILMX from PHILMWS95 to PHILMX90 (see screenshot below):
After this change the simulation run will return successfully without errors. Note that typically for engineering calculations, the difference between the various steam models is very small. Changing the fugacity route has a very small effect on the saturation pressure calculations.
Keywords: STEAMNBS, IAPWS-95, Error Message, Isentropic, Compressor, Turbine.
References: None |
Problem Statement: This Knowledge Base article answers the following question:
Does any AspenTech software product (IP.21, AtOMS, Advisor?) support /3GB memory switch as described in the Microsoft article: Memory Support and Windows Operating Systems
(link to the article provided below)
http://www.microsoft.com/whdc/system/platform/server/PAE/PAEmem.mspx | Solution: Neither Aspen InfoPlus.21 (IP.21), nor any other AspenTech software product supports /3G memory switch technology as described in the above MS KB article. However, there really isn't a need as even the largest Aspen Advisor and Aspen AtOMS models do not come close to using the address space available under 32-bit editions of Windows.
Keywords: None
References: None |
Problem Statement: 当安装或者升级的时候点击Install会出现如下错误 | Solution: 1:
停止安装并确认如下事项：
1. 当安装的时候需要有本地管理员权限。
2. 本地Administrators组要对C:\WINDOWS\Installer文件夹有完全控制权限
如果无法看到此文件夹要在文件夹选项中取消对隐藏受保护的操作系统文件(推荐)的选择和选择显示所有文件和文件夹
3. 重新进行安装Solution 2:
1. 此问题也会发生在把系统语言设置为挪威语[Norwegian (Bokmal)]的时候. 默认语言选择US-English会正常进行安装。
更多有关此问题的信息可以查看http://consumer.installshield.com(可供用户查看常见错误的网站)中的Error -1607: Unable to Install InstallShield Scripting Run TimeSolution 3:
1.确认Windows Installer服务为启动状态。如果为停止状态那么也会出现此问题。Solution 4:
此问题也会出现在把安装介质拷贝到网络路径时。此时需要把安装文件拷贝到本地路径中或者直接在本地用DVD进行安装。
Keywords: 1607
无法安装
Installshield
Scripting Runtime
CN-
References: None |
Problem Statement: 설치 혹은 업그레이드할때 아래와 같은 오류 발생: | Solution: 1:
설치작업을 중지하고 아래와 같은 내용 확인:
1. 설치작업을 관리자 권한으로 진행하는지 확인.
2. Administrators그룹은 C:\WINDOWS\Installer 폴더에 완전권한이 있어야 합니다.
만약 이 폴더를 볼수 없으면 폴더 옵션에서 보호된 운영 체제 파일 숨기기(권장)를 선택 안함 및 시스템 폴더 내용 표시
3. 설치 다시 시작.Solution 2:
1. 본 오류는 언어를 노르웨어[Norwegian (Bokmal)]로 선택했을때도 발생합니다. 디폴트로 언어를 US-English 로 변경하면 문제가 해결됩니다.
상세한 내용은 사이트 http://consumer.installshield.com(자주 발생하는 오류 검색 사이트)의 Error -1607: Unable to Install InstallShield Scripting Run Time 에서 볼수 있습니다.Solution 3:
1. Windows Installer서비스가 시작되였는지 확인. 만약 서비스가 시작되지 않았다면 이런 오류가 발생합니다.Solution 4:
본 오류는 설치파일을 네트웍 경로에 저장하였을때도 발생합니다. 설치시 파일들을 로컬 컴퓨터 경로에 복사 혹은 직접 DVD로 설치해야만 가능합니다.
Keywords: 1607
설치 오류
Installshield
Scripting Runtime
KR-
References: None |
Problem Statement: Does the repository TSK_DHIS_AGGR have to have its settings (number of file sets, tuning parameters, etc.) match those of any other repository (for example, TSK_DHIS)? | Solution: This repository does NOT need to match the settings of TSK_DHIS (if it exists) or any other repository. They work independently.
Additional details about TSK_DHIS_AGGR, which is a repository used for the Stored Best Fit functionality introduced beginning in Aspen InfoPlus.21 V7.3.02, can be found inSolutions 134042 and 134045.
Keywords: None
References: None |
Problem Statement: Default options provided on IP.21 database for IP_VALUE_FORMAT fields used on IP_DiscreteDef, IP_AnalogDef or other type of records cannot be the suitable to use for some cases, this | Solution: provides explanation and guide on how to add new options on the list available for this field.Solution
List of options in IP_VALUE_FORMAT is defined by Selector records found in IP.21 database, this kind of records works as enumerated options binding an integer number with a string value; It is possible to find all available selector records on IP.21 with definition like “Select<xx>Def” where xx correspond to the length of the options that can be written on it:
It is possible to add new selector following this steps:
1) Open IP.21 Administrator.
2) In this example, to add a selector record for option YES/NO/CANCEL, since “Cancel” is the larger options with 6 character, it is necessary to use a selector of at least 6 character length, in this example we will use Select6Def nut any bigger selector will work too, right click on it and select Record defined By Select6Def:
3) Define a proper name for the selector record, for example Yes/No/Cancel, click Ok and refresh the tree to see new record added.
4) Change the value of #_OF_Selections field to the number of options you want, optionally add an extra value that will work as null value, in this case for add Yes, No and Cancel option we leave this number as 4:
5) Write the option on the repeat area of the record under Select_Description field:
Verify that record can be used as part of the IP_Value_Format field on other records
Keywords: Selector
IP.21
IP_VALUE_FORMAT
References: None |
Problem Statement: After deleting / Removing a repository in the InfoPlus.21 administrator the Health Monitor is run and still shows the removed Repository. | Solution: This issue will occur when you delete a repository but have not stopped and started Infoplus21. InfoPlus21 whenever a Repository is added or removed has to be restarted in order for the snapshot to take effect.
To restart InfoPlus you will need to stop Ip21 from the Manager or Administrator
Keywords: Health Monitor
Delete Repository
Repository
InfoPlus.21
References: None |
Problem Statement: When trying to upgrade a snapshot using the Aspen InfoPlus.21 Database Upgrade Wizard, the upgrade process fails instantly with the following message:
Error in loading InfoPlus.21 snapshot.
The error terminates the upgrade process. | Solution: The snapshot in question is actually the base model snapshot. When selecting the Typical upgrade option this snapshot (named InfoPlus21DB.snp) can be found in the \AspenTech\InfoPlus.21\db21\etc folder. Make sure the snapshot exists and that file permissions allow you to read the file.
Keywords: UpgradeWizard
References: None |
Problem Statement: When I try to import heat exchanger information from Aspen Plus into EDR I cannot import it and Aspen Plus is showing me the following error:
Also when I click the Size Shell&Tube button in Blocks| <block_name>| Setup folder, specification tab in Aspen Plus. Aspen Plus shows the error below: | Solution: This error appears when the Aspen Plus bkp file contains a dot “.” In the file name; for example xxxx.xxx.bkp. This is a common practice when you have installed several versions of Aspen Plus in the same machine and you want to include the version in which the file was created in in the file name; for example xxxxV8.4xxx.bkp or xxxxV8.0xxx.bkp
When an .appdf file is created, Aspen Plus needs to copy the full name of your file, and if it contains a dot, Aspen Plus will show this error.
The workaround is to rename the file and remove the dot “.” Then Aspen works with EDR without this issue.
Keywords: Import procedures, Aspen Plus, EDR, error
References: None |
Problem Statement: What properties are used with a free-water or dirty-water method that contains only water? | Solution: When you use the free-water or dirty-water calculation method, if a stream contains only water, all properties for the stream are calculated using the free-water method as if it was the main property method.
Keywords: None
References: None |
Problem Statement: What type of centrifuge is recommended for separating solid particles from thick suspension of coarse and semi-coarse particles (80-100 micron) in liquid? | Solution: A pusher type centrifuge can be used for separation of coarse solid particles from suspension. The centrifuge combines both centrifugation and filtration operation. A perforated drum is used as rotor for drainage of liquid. Inside the drum the separation of liquid and solids takes place. The product is transported from the suspension feed at the one end of the drum to the solids discharge at the other end by an oscillating axial mechanism
The solids' concentration of the suspensions can vary from 30 % of volumetric amount up to paste-like condition. Less than 30% volumetric concentration of solids should not be used to avoid functional problems of pusher centrifuge.
Key Words
Pusher, Centrifuge, Coarse, Semi-coarse.
Keywords: None
References: None |
Problem Statement: When importing a file that uses OLI into a simulation, there is an error about the Chemistry.
****EXECUTION ERROR WHILE PERFORMING INITIAL ENTHALPY CALCULATIONS FOR
STREAM: NAOH
Error: A chemistry model is required to use the
OLI property option, but none was found. | Solution: OLI needs to have the database .dbs file in the working directory which is generally the directory where the simulation file is located. When importing from a file in another directory, you need to manually copy the .dbs file into the working directory.
Keywords: None
References: None |
Problem Statement: In Aspen Plus version 7.3 and earlier, you were able to place the model blocks in the simulation and adjust their sizes by selecting Resize Icon from the right mouse button. How is this done in version 8.6? I have a distillation column with a large number of side streams leaving and entering the column. It is hard to see what is going on without the ability to increase the size of the block on my screen relative to the other pieces of equipment in the flowsheet. | Solution: In V8.4, Resize Icon was removed from the drop-down list. Click and drag the handles on the corner of the selected block to resize the icon.
Keywords: None
References: None |
Problem Statement: When using the ‘Assistant – Property method selection’ from Methods | Specifications | Global (Tab) or from the Home (Ribbon) | Tools, and clicking on the ‘Next’ button, one can select between two options: Specify component type or Specify process type. However, there are some cases where those options do not work properly and the next window which is supposed to open does not appear at all. | Solution: In order to avoid this, one has to change the security level under Windows Internet Options to ‘Default’. If changing to this level does not help, change it to ‘Low’.
This allows the assistant to get access without restrictions to the Aspen Plus Online Help. See screenshot below.
Keywords: Property Method Assistant, Windows Internet security level.
References: None |
Problem Statement: When trying to restore a database such as the legacy databanks in APLDB to the Aspen Properties Enterprise Database (APED), I get the message:
Error occurred while trying to restore the database from this file. [SQL-DMO]This cache contains no result sets, or the current result set contains no rows. | Solution: You need to check which account is being used to run SQLExpress. This can be checked in the Control Panels, Administrative Tools, Services. Do a right mouse click on the SQLExpress service, Properties and check the Log On account.
The error will occur if the account used does not have read permission in the folder where the database file used to restore has been stored.
For example, assuming that that SQLExpress service is runing under NT AUTHORITY\NetworkService account (default), by default this account does not have read permission to a folder created on the desktop. Hence it will not be able to restore.
You can resolve this problem by adding read permission (right click on the file and security tab) on this file to all users (or to NT AUTHORITY\NetworkService) on this machine. The other option is to move the file to some other location (such as C:\) where it can be read by NT AUTHORITY\NetworkService account.
We plan to improve the wording of the error message for future versions of Aspen Property Entreprise Database manager.
Keywords: APED
CQ00453754
References: None |
Problem Statement: When running a model with calculator in Aspen Plus V7.2 with Excel 2010, the error message VBTableData object cannot be created is dispatched in the Control panel. What can be done to eliminate the error message. | Solution: The problem is that Aspen Plus V7.2 does not work with MS Excel 2010. There is currently no plan to address this issue for V7.2.
The alternatives are
1. Run V7.2 with Excel 2007or 2003.
2. Move the user calculation currently in Excel to use Fortran.
Keywords: calculator, Excel 2010, User2
References: None |
Problem Statement: How to retrieve the vapor flow profile from Pres Relief calculations? | Solution: How to report the vapor flow in the property profiles from the Pres Relief calculations?
Those values are not reported directly in the results form from the Pres Relief tool in Flowsheeting options. However, there is another way to extract those results from Aspen Plus.
The Pres Relief tool calculates the pressure and temperature for the different scenarios and then performs a flash calculation to report the vapor fraction with the same property method that is specified in the block options.
To report any other property related to that same stream and pressure relief device, you can create a sensitivity analysis and set it up as a case study; then select the pressure and temperature from the property profiles and enter them as the “Vary” variable in the Case Study and specify the desired property to be reported as the “Define” variable.
1- In the attached example, a steady state flow rating of a relief system is modeled. The calculations are referenced to a stream in the flowsheet and details of the relief device, inlet pipes and tail pipes are given.
2- Check the results in Flowsheeting options | Press Relief | SSTATE, Steady-state results/ Property profiles. As can be seen you can only report the Pressure, Temperature and Vapor Fraction. To get more properties, a case study inside a sensitivity analysis is needed.
3- Go to Model Analysis Tools | Sensitivity, New.
4- In the Vary tab, select two variables that correspond to inputs for the stream that is referenced in the Pressure Relief model, in this case Pressure and Temperature.
5- In the Define tab, create variables for Vapor fraction (VFRAC) and the molar flow (FLOW) of the referenced stream.
6- To calculate the Vapor Mole Flow (VFLOW), we can execute a Fortran command that will call the total mole flow of the stream (FLOW) and multiply it by the Vapor fraction (VFRAC) to calculate VFLOW.
7- In the tabulate tab, crate the list of variables to be reported in the results, in this case VFRAC and VFLOW.
8- In the Options tab, select “Do not execute base case”
9- In the Cases tab, you can copy and paste the description of the case points and the pressure and temperature points from the results of the Pres Relief tool.
10- Run the simulation and review the results
Keywords: Pres Relief, Sensitivity Analysis, Case Study
References: None |
Problem Statement: In the new Aspen Plus User Interface from V7.3.2 and higher, after I open a new tab, older tabs disappear. How do I find tabs that have disappeared when new ones are created? Are they automatically closed when too many tabs are opened? | Solution: Using Workbook mode in V7.3 and earlier, the size of the tabs was automatically reduced as more tabs were created. In V7.3.2 and higher, the size of the tabs remains the same and new tabs will push the oldest tabs off the screen. At the right of the tabs, there is an icon that can be used to see a list of all of the tabs that are open.
The performance of the user interface can degrade when too many tabs are opened. One convenient feature is that if you right mouse click on a tab, you can select Close Other Tabs in order to close all tabs except the one that is selected.
Keywords: None
References: None |
Problem Statement: What are the appropriate steps to take when the following error shows up on the control panel?
* WARNING IN PHYSICAL PROPERTY SYSTEM
NRTL BINARY PARAMETERS FOR ALL COMPONENT PAIRS ARE ZERO,
YOUR RESULTS MAY NOT BE ACCURATE. PLEASE REVIEW AND PROVIDE BINARY
PARAMETERS AS APPROPRIATE. | Solution: This error means that your NRTL parameters are all zero so you should look at them to see if that can be rectified.
Without the NRTL parameters, the case will be modeled as ideal. This will not happen if you have values filled into the NRTL parameters table. You can achieve this going to Tools | Retrieve Parameter Results? This is also dependent upon what properties you have chosen to use for your simulation, so if you are unsure be sure to make use of the property assistant found under Tools | Property Method Selection Assistant. You can also estimate parameters using UNIFAC or you can regress your own parameters.
Keywords: NRTL, physical property, binary parameters
References: None |
Problem Statement: In some models built in V7.1 or earlier versions, D2887 assays are entered. When the models are opened in V7.2 or later versions, the viscosity calculated for the streams with D2887 assay can be significantly higher. What has caused this discrepancy between versions? | Solution: There are many ways to generate distillation curve for a crude. The most accurate way is TBP curve (true boiling point curve). In Aspen Plus, only the TBP curve is used for generating the pseudo components. These pseudo components and their properties are used in simulation model to represent the crude feed and subsequent processing. If a crude is characterized using a method other then TBP, the distillation curve has to be converted to TBP curve first. After the conversion, the pseudo components can be generated from the equivalent TBP curve.
In Aspen Plus V7.2, the conversion algorithm from D2887 to TBP conversion has been replaced with the same conversion in Aspen HYSYS. This change is because the Aspen HYSYS covnersion generates better TBP curves. We consider this to be an improvement in Aspen Plus V7.2. The conversion algorithm in Aspen HYSYS has been in service for many years, and has been proven to be accurate.
One side effect is that this conversion calculates the viscosity significantly higher than the previous versions of Aspen Plus. This will have an impact on the equipment design and rating.
Keywords: D2887, viscosity
References: None |
Problem Statement: How to find the usability improvements in a newer version of Aspen Plus? | Solution: There is an easy way to quickly see the usability improvements added to Aspen Plus.
1. Open an Aspen Plus file and click on help menu icon (on the top right hand corner in the window below).
2. Click “What’s new in Aspen Plus V8.8�, if you are interested to know about the usability improvements in V8.8.
3. Click workflow and usability enhancements.
Keywords: What's new, usability, improvements, workflow
References: None |
Problem Statement: My simulation crashed and created a .dmp file. Can I send this to AspenTech without my .bkp file? | Solution: The .bkp file and the steps to reproduce the crash are all that is needed for development to investigate the problem. The .dmp (dump) file is not useful by itself; however, the .dmp file is sometimes helpful in diagnosing a non-reproducible crash when we have the .bkp file also. If a .log file is created, that file can also be useful, again with the corresponding .bkp file. In addition, if the crash is not reproducible, any general information about what you were doing before the crash is also helpful.
Keywords: None
References: None |
Problem Statement: When the user specifies the parameter value of SRKWF manually for a component, under Methods | Parameters | Pure Components | New (Scalar):
This value does not seem to be updated when clicking on the Retrieve Parameters button and the result value of SRKWF remains still as 0, and confirm checking the results under Methods | Parameters | Results | Scalar: | Solution: User input will not affect the retrieved results shown on the form. User input will be included in the generated input file and therefore, it will be used in the simulation. In this case, the generated input file will include the following lines:
PROP-DATA PURE-1
...
PROP-LIST SRKWF
PVAL CIS-2-01 3E+4
This value was input by user and will be used in the simulation. Retrieving will show parameter values either stored in our databanks or estimated from internal method such group contribution. There are no values stored for SRKWF in the A+ databanks for any component. Hence the value for the component was estimated by group contribution. No values can be estimated by group contribution for this component this component in specific. So the value as 0 will be displayed.
Keywords: SRKWF, Scalar Parameter.
References: None |
Problem Statement: How to change the concentration basis for the reaction rate equation? | Solution: It is possible to select the concentration basis of a reaction. The concentration basis determines which form of the power law expression will be used. See the help for more information.
The steps for changing the concentration basis are as follows:
1. Go to the particular reaction set, for which concentration basis of the rate equation has to be changed. E.g., R-1 reaction set shown below.
2. Click Kinetic tab
3. Change [Ci] basis.
Keywords: Concentration basis, reaction set, rate equation
References: None |
Problem Statement: When the user tries to regress an equilibrium reaction’s constants, these constants cannot be regressed via Regression mode under the Properties Environment in Aspen Plus or Aspen Properties. | Solution: Instead of using Regression mode under the Properties Environment in Aspen Plus or Aspen Properties, use the ‘Data Fit’ option in the regular simulation mode under Simulation Environment | Model Analysis Tools | Data Fit, in order to adjust the chemistry A, B, C, D values for the equilibrium constant.
Keywords: Regression, Equilibrium Reaction, Equilibrium constants, Data Fit.
References: None |
Problem Statement: I can’t find a certain compound in Aspen Plus databanks, but it is available in the online NIST website: What can I do? | Solution: NIST TRC is a third party pure component databank that we make available for users to broaden our own resources. Aspen Plus includes a built-in version of the NIST databank that it is updated in each Aspen Plus release. You can add it by selecting the NISTVXX NIST-TCR under Properties / Specifications / Enterprise Database. Where XX refers to the Aspen Plus version you are using.
If you still can’t find a certain component, but it is available in the online NIST databank, there is a workaround to easily add it to your simulation through the component .mol file. Please find below the steps required:
1. Go to the NIST Webbook and search for your compound:
http://webbook.nist.gov/chemistry/cas-ser.html
2. Download the .mol file with the component structure. You can obtain the .mol file from other resources such as www.chemicalbook.com.
3. Go to Aspen Plus and create a new user defined component:
4. Import the mol file downloaded from the NIST online or from other source:
5. Select “evaluate using NIST TDE”. This option connects with the online version of the NIST databank.
After importing the parameters from the NIST databank, your component will be fully defined and ready to be used in your simulation.
Keywords: NIST Databank, mol file, component not found.
References: None |
Problem Statement: What are typical conveyance values in dense phase for pipes in solids conveying? | Solution: In order to use the dense phase conveying in Aspen Plus the throughput will generally be larger than 5 ton/h and have a pressure drop as high as 1–6 bar.
This method of conveyance is adopted to reduce gas requirements and to avoid wear of the conduit and abrasion of the product conveyed. The load ratio “μ” can be increased to 10–150. The superficial gas velocities are merely 2–15 m/s and are often less than the settling velocity. The diameter of the pipe varies between 50 and 300 mm.
Almost all products with particle sizes between 1 mm and 10 mm can be conveyed. Please See the figure below.
Notes: The particle diameter on the conveying input form is optional, if the cell is empty, the diameter will be determined based on the PSD in the feed.
The units of d50 (Mean particle size for the feed) are micrometers.
CF= Shape Factors
ϕ= Flattening Coefficient.
Keywords: Dense Phase Conveying, friction factor, Shape factors
References: s : Muschelknautz U., 2010. Pressure Drop in Pneumatic Conveying Systems. In: VDI Heat Atlas 2nd Edition, ed. VDI Gesellschaft. Berlin Heidelberg: Springer-Verlag, pp. L3.3 1207- 1226. |
Problem Statement: My exact packing is not available in the pack rating or sizing for Aspen Plus. What should I do? | Solution: The user can use user-defined packing in Aspen Plus, but not in HYSYS. In Aspen Plus, select USER as the Packing Type. Then the user needs to enter the packing parameters. The user can only do this under Sizing and Rating | Packing Sizing or Packing Rating:
Sample Steps for Pack Rating:
1. Navigate to the Sizing and Rating folder under RadFrac and select Pack Rating
2. Select the column packing section you are interested in by specifying the corresponding stages
3. Select type as user from the drop down menu.
4. Fill in the fields under the packing characteristics section. For vendor and material, unlike when you have a pre-built type, you will only be able to select generic and standard respectively for each category. Under dimension, it will be USER. You will fill in the section diameter and packing factor fields only.
5. Under packed height, choose to specify packed height per stage or section packed height.
Keywords: Packing, Sizing, Rating, Trays, Columns, User Specified
References: None |
Problem Statement: Aspen Plus Automation with C#: How to create a new reference to Aspen Plus COM starting object? | Solution: The following lines of code illustrate how to create a new instance of the starting COM object in Aspen Plus, the one that will give access to the rest of interfaces that it implements.
For a new document:
Type aspenPlusType = Type.GetTypeFromProgID(Apwn.Document);
IHapp aspenPlus = Activator.CreateInstance(aspenPlusType) as IHapp;
For an existing document we should use a marshal.bindtomoniker method:
//pathToFile is a string variable with the file path
IHapp aspenPlus = System.Runtime.InteropServices.Marshal.BindToMoniker(pathToFile) as IHapp;
Keywords: C#, COM object, ActiveX.
References: None |
Problem Statement: Version 7.1 of Aspen InfoPlus.21(IP.21) introduced a new feature called the IP.21 Configuration Tool Add-In.
It allows a user to retrieve and update current records and add new records from Excel Spreadsheets
The first step is after selecting the choice from the Aspen drop-down menu would be to click on Retrieve Definition Records. From there you will be prompted for the Aspen InfoPlus.21 database that you want to work with.
This article explains why you may encounter the following error when clicking on Retrieve Definition Records
Can't find the module, executing command failed! | Solution: Part of the installation of this new feature is to load a file called 'excel.exe.config' into the same directory as excel.exe.
This file contains information to tell Excel which version of the .NET framework (v2.0.50727) has been installed.
This is important for the IP21 Tag Configuration because the IP21 Tag Configuration addin has a .NET dependency.
If the excel.exe.config file is not in the same directory as excel.exe then you can get this specific error.
With V7.1 AspenTech only supports Microsoft Office 2003 or 2007.
If you are using a version other than these, such as Office-2002 (XP edition), then the installation will not correctly store the file in the correct location.
However it can be found in
.....\AspenTech\APEx\Pe\Addin directory
The easy workaround is to copy the file from the AspenTech directory to the directory containing excel.exe
Keywords: None
References: None |
Problem Statement: What kind of pressure drop correlations are used when vendors' packings are used in Pack Rating calculations? How does one check that the appropriate correlations are being used? | Solution: When performing a Pack Rating calculations in Aspen Plus, the pressure drop correlation used automatically default to vendor correlations if nothing is specified in the Design/Pdrop input form, Pressure drop calculation method field.
A list of the available correlations from vendor is found in the online Help, go to menu Help -> Help Topics -> Appendix A: Advanced Distillation Features. The page is attached to theSolution for convenience.
Note that if Raschig or Sulzer is chosen as vendor, the pressure drop calculation method cannot be changed to other type, the system will not allowed the change. This option is available if other vendors are selected.
How does one check the pressure drop correlation used in the simulation run?
The information will be reflected in the Report, PACKING RATING CALCULATIONS section. Generate a Report by going to menu View -> Report, Simulation. In general, the Reports contains many useful details that will be difficult to display in the user interface.
Some examples are shown below.
Figure 1. Sulzer packings are used.
Figure 2. Norton packings are chosen
Keywords: Pressure drop, packings, sulzer, norton
References: None |
Problem Statement: How can I correctly release Aspen Plus COM object in VB.NET and C# (close Aspen Plus process) | Solution: VBA (old vb6 engine) and .NET are very different in the way they handle COM (managed vs unmanaged runtime environment). In VB.NET or C#, unlike VBA, the following code won't release the interface pointers on the COM object, so Aspen Plus process won't shut down:
myAP.Visible = False
myAP = Nothing
They will be dropped automatically when they are garbage collected at the end of the execution thread, and if Aspen Plus is not visible its process will end correctly. Which is in most cases good enough, but if you want to keep control over the lifetime of the COM object, you should use an explicit marshal release method on that object:
myAP.Visible = False
myAP.Quit()
System.Runtime.InteropServices.Marshal.FinalReleaseComObject(myAP)
The code above will release the object and will immediately close Aspen Plus process.
Keywords: Close Aspen Plus, Automation, COM Interfaces.
References: None |
Problem Statement: Aspen Shell & Tube Exchanger can be linked to Aspen Plus to allow users to design, check/rate and simulate heat exchangers within their simulation. The method to link is described in the | Solution: #130470 “Design heat exchangers for chemical processes using Aspen Shell & Tube Exchanger and Aspen Plus”.
When this method is used, sometimes it may be noticed that the outlet temperature specification supplied to Aspen Plus may be slightly different to the outlet temperature given in the Results of the Shell & Tube program.
Applicable versions
Version 7.3 and higher
Solution
ThisSolution is a workaround when using either the Design or Checking methods for the rigorous Shell & Tube method with Aspen Plus.
In order to make that both temperatures (specification and in the results) match each other, follow the next steps:
- Go to the Aspen Plus simulation to the Heat Exchanger block.
- In EDR options, specify the estimated outlet pressure as the difference between the inlet pressure and the specified maximum deltaP. In the case of the hot stream, the inlet pressure is 1.313 bar and as the maximum delta P is given as 0.1 bar, the outlet pressure will be 1.213 bar. This procedure should be repeated for the cold stream as well.
- Run the simulation. Now, both Aspen Plus and EDR have the same outlet pressure and the same temperature.
In the Aspen Plus simulation, Simulation environment | Blocks | HeatX | Setup | Exchanger specification:
In the Aspen Plus simulation, Simulation environment | Blocks | HeatX | EDR Browser | Thermal Hydraulic Summary | Performance | Overall Performance:
Keywords: Aspen Plus, EDR, outlet temperature match
References: None |
Problem Statement: Can I adjust the flooding factor for the flood calculation to predict flood for the actual diameters that have been obtained from plant data?
As an example it is known, from plant data, that flooding occurs for a 3m diameter column and it is required to carry out simulations using the Radfrac model in such a way that, similarly to plant data, flooding can be adjusted to occur for the 3m diameter column.
So, can I adjust an Radfrac model with 3 meter standard sieve trays to flood at this diameter to allow me to run different studies such as different feed points, pump around loops and different feed compositions etc. | Solution: When carrying out a tray rating study the flooding calculation method can be selected from a drop down menu, in the Tray Rating | Setup | Design / Pdrop sheet, as shown in the screen shot.
For trays the Fair correlation uses the following correlation:
The Fair72 correlation is an improvement of the correlation above and uses the following equation:
Where CSB is the reduced flooding velocity and TS is the tray spacing. For more detailed information on the correlation refer to the online help, at the topic “Fair and Fair72 Jet Flood Correlations”, and see the screen shot below.
Flooding is therefore dependent on the tray spacing. For a specified tray type Aspen Plus fixes the tray spacing and hence the flooding is accordingly calculated from the above correlation. If user changes the default tray spacing values entered by Aspen Plus in the Tray Rating | Setup | Specs sheet, then the flooding factor calculation can be adjusted for fitting plant data.
Keywords: : Radfrac, Tray Spacing, Flooding Calculations
References: None |
Problem Statement: What does the warning message Fluid velocity is out of range to calculate Flow Regime� mean in Aspen Plus?
*WARNING
FLUID VELOCITY IS OUT OF RANGE TO CALCULATE FLOW REGIME
GAS SUPERFICIAL VELOCITY MUST BE BETWEENÂ 0.05 AND 500 M/S
LIQUID SUPERFICIAL VELOCITY MUST BE BETWEENÂ 0.005 AND 50 M/S | Solution: The correlation used to determine flow regime for pipe results has limits of applicability based on superficial liquid and vapor velocity. Since V7.2, when the liquid and/or vapor superficial velocities are outside the ranges of applicability of the Taitel/Dukler correlation used to calculate the result, flow regime is reported as Undetermined. For more information on flow regimes seeSolution document 117889 or the Flow Regime help topic found under Using the Simulation Environment -> Unit Operation Models
Keywords: Fluid velocity, flow regime, superficial velocity, pipe, pipeline, Taitel, Dukler
References: Manual -> Chapter 6: Pressure Changers -> Pipeline Reference -> Flow Regimes.
This only affects the flow regime printed in the block results and does not affect the flow regime calculations used within some two-phase correlations such as Beggs-Brill, which may differ from this flow regime and may be able to calculate flow regime where this correlation does not. |
Problem Statement: I added two new assays into an old simulation which already have assays and generation objects.
When I try to select either of these two assays to be the composition of a feed stream (old or
newly created ) the assays do not show up listed on Streams Input folders, though previously created
assays show up.
However, If I create a new case and add assays, they appear listed on streams input forms.
I need assistance with assigning the composition of two streams with these new assays on my old
model. | Solution: When a model contains Assays, Generation objects, which defines unique set of pseudo components
to be generated for a given set of selected assays, user have to define additional Generation objects
and associate them with the new assays before the new assays can be selected on the Stream/ Input
folders. That is the rule. Library model crude.bkp (C:\Program Files (x86)\AspenTech\Aspen Plus
V7.3\GUI\Xmp) is used to demonstrate the above. Figure 1 shows that a new assay added to model
does not appear listed under Stream AGO Input folder until a generation object (G-1) associated with new
assay is created (See Figure 2).
Figure 1. V7.3 Library model crude.bkp before creating Generation object associated to new assay.
Figure 2. V7.3 Library model crude.bkp after creating Generation object associated to new assay.
If Generation objects are not created (No Generation object exist on model), all the defined assays
are lumped together to create a single set of pseudocomponents. In this case, all assays and blends
will appear on Stream Input folder.
Keywords: Petro Characterization, Assays, Generation objects.
References: None |
Problem Statement: If I want to conduct a typical calcination reaction within the RGibbs model in Aspen Plus, I do not get the required temperature that is typically reported for the reaction listed below:
Reaction: CaCO3=CaO+CO2
I do not understand why this is the case. The observed temperature is usually lower than the known reaction conditions as validated by Gibbs free energy calculations. | Solution: It is a known issue that calcination takes place at specific conditions and if the temperature is too low, the reaction can’t take place. But when the user’s model has H2O present in the process the reaction conditions can change. H2O present in the gas will cause a smaller partial pressure for CO2, which in turn shifts the equilibrium to the right at the temperature specified, depleting the amount of CaCO3. To verify, the user can reduce the H2O in the gas to see its impact on the calcination temperature.
Below you can see simple calcination model, when steam is present in process.
In this simulation we used CaCO3 as a FEED stream and H2O in STEAM stream. In 900°C reaction proceeds correctly and that’s OK, but when user changes a temperature to 850°C he should not get reaction products in outlet stream, but in this example CO2 and CaO are present. To check how water stream change equilibrium and product efficiency user has two options:
Go to folder: Streams| Steam| Input and in Mixed tab, choose smaller H2O flow rate and observe results changes.
Use sensitivity Analysis to study temperature and H2O flow effect to reaction efficiency.
Please find attached the example file where all processes has been shown.
Keywords: Calcination, RGibbs,
References: None |
Problem Statement: Radfrac경우, V8.0부터 Property method을 변경하거나 선택하기 위해 사용되는 block options form이 더 이상 지원되지 않는다. | Solution: Block options form은 Radfrac이외의 모든 block에는 기존처럼 이용가능하다.
Radfrac경우, 다음 경로에서 block option form을 확인 할 수 있다
Radfrac |Specifications folder| block options
Please findSolution 136908 for the original English version.
Key Words
RateSep
Keywords: None
References: None |
Problem Statement: When calculating the heat capacity (Cp) of water with various property methosd, we found that the heat capacity calculated using IAPWS is extremely large around critical point.
The Cp using IAPWS is 1501 cal/gm-K at 218.3 atm Cp using STEAMNBS is 1380 cal/gm-K at 218.1 atm.
Are these reliable results? | Solution: The heat capacity (Cp) of a substance is infinity at the critical point; therefore, the large values observed with different property methods are expected.
Keywords: results, heat capacity, limits, range
References: None |
Problem Statement: When performing flash calculations involving certain solid components, the calculation may get hung up at a certain point, unable to converge.
In other types of calculations, apparently anomalous jumps in enthalpy may be observed for solid components at certain temperatures.
For example, for Olivine (Ca2SiO4), the enthalpy diagram has discontinuities.
Cause
These solid components have more than one solid form. The convergence failure or enthalpy anomaly occurs at the transition between these forms. The behavior is analogous to a phase change. | Solution: For many components, especially in the INORGANIC databank, multiple versions are available which represent the individual solid forms, as well as a single component which represents the entire range. Commonly, the parameters CPSXP1, CPSXP2, etc. are provided to specify enthalpy for the combined component. You may examine the temperature ranges on these parameters to find the transition temperatures.
Instead of using this component, you can choose to use the component representing the solid form you expect to dominate and ignore the transition, or you can use multiple components and model the transition as a reaction between the components representing the different forms.
If these components are not available, you can still perform similar modeling with user components with appropriate data.
For the example of Olivine, you can see that multiple solid forms are available in the Inorganic databank.
Keywords: None
References: : CQ00132981 |
Problem Statement: I would like to set the operating pressure of Radfrac from a calculator block. I cannot decide which variable I should refer to in the calculator block? There are PRES, PRES-STAGE1, PRES-STAGE2 etc. I am not sure which one I should choose as output variable for the calculator | Solution: If you use the variable name as described below (stage-pres) (see screen shot and the attached example file) then you should be able to specify the pressure for any stage in the column. Note the field ID1 refers to the stage number.
The calculated pressure can be verified on the TPFQ tab in the Profile form for the RadFrac block.
Keywords: RadFrac, CalcBlock, Stage-Pressure
References: None |
Problem Statement: I am getting an error in the Control Panel for a design specification:
MANIPULATED PARAMETER NOT CHANGING. PROBABLE CAUSE:
EITHER TOL-SPEC TOO SMALL OR XTOL TOO LARGE.
Depending on specifications, this may be accompanied by:
THE CONVERGENCE LOOP WILL BE EVALUATED ONCE MORE.
What are TOL-SPEC and XTOL ? How can I fix this problem? | Solution: The error message indicates that the variable specified in the design specification changes very rapidly with respect to the manipulated variable near the target value. This results in the design specification taking smaller and smaller steps. It converges, in the sense of reaching a near-constant value, but it fails to reach the goal specified in the design specification. For example, if you want the vapor fraction of a stream containing a pure component to be 0.5, and you are manipulating the stream's temperature, the design specification will converge to the boiling point of the component, but the vapor fraction will always be 0 or 1 and never 0.5. This kind of problem can't be solved exactly, so Aspen Plus stops when the steps become too small.
For the design specification, in the TOL-SPEC input language sentence, tol is used to enter the design specification tolerance. –tol < expression1 – expression2 < tol where tol is any valid Fortran arithmetic expression. This is the tolerance on the Flowsheeting Options | Design Specs | Input Spec sheet.
Tolerance values specified in the DESIGN-SPEC paragraph are superseded by tolerance values (XTOL) specified in a CONVERGENCE paragraph.
In a convergence block such as SECANT which is the default for a design-specification, XTOL is an alternative tolerance on the manipulated variable. Iterations stop when the change in the scaled manipulated variable is less than XTOL. The variable is scaled by dividing by the absolute value of the lower limit or the upper limit, whichever is larger. The default is 1x10-8. This is specified on the Convergence | Options Methods | Secant sheet.
There are a few ways to resolve the issue depending on its cause.
In some cases, as in the boiling point example above, the problem may be impossible and you should specify it in a different way. If there is aSolution, but the curve to reach thatSolution is very steep, you may adjust tolerances. In the message, TOL-SPEC refers to the tolerance specified in the design specification, which specifies how close theSolution must be to the target value. You can increase this value to allow aSolution farther from the target to be considered converged.
In some convergence blocks such as Secant, there is a tolerance (X Tolerance) which applies to the manipulated variable. This is referred to as XTOL in the message. This tolerance specifies the minimum step size before the block stops, and the message appears when this tolerance is reached without converging the design specification. If you want it to keep trying smaller and smaller steps, reduce X Tolerance on the Convergence | Options | Methods | Secant sheet or the Input | Parameters sheet of an individual Secant block.
In some cases, the Bracket feature of Secant convergence blocks may help problems like this. When it is enabled, if the convergence it not making progress, it tries to bracket theSolution with manipulated variable values on either side of theSolution and uses interval halving to find theSolution. This is slower than the Secant technique in general but can help when Secant cannot make progress. If the curve is too steep relative to the specified tolerances, it may still lead to this message.
Keywords: XTOL
TOL-SPEC
Design-spec
References: : CQ00694253 |
Problem Statement: I have an RBatch reactor in the simulation and it is specified with continuous feed for a certain period. After running the simulation, the following error message is displayed:
**Â Â ERROR IN THE BLOCK PARAGRAPH WHICH BEGINS ON LINE 266
     BLOCK NAME: B1   MODEL NAME: RBATCH    SKW: FEED-PROF    TKW:
     FPROF-TIME
     INVALID USE OF UNITS SPECIFICATION IN BRACES OR BRACKETS.
     SENTENCE IGNORED.**
How do I prevent this error? | Solution: To solve this problem follow the instructions below:
1. Export the simulation file as an input file. To do it go to File | Export | Export a document | Select input file *.inp.
2. Open the input file in the Notepad application.
3. Check continuous feed time: you may see that there are some units specified whilst in the graphical user interface there is no input related to the continuous feed time.
4. Remove the units from the input file.
5. Now, open the input file in Aspen Plus and run the simulation. It should run without problems.
Keywords: RBatch, continuous feed time
References: None |
Problem Statement: In V7.3.2, the menus and toolbars have been replaced with a ribbon interface. The File menu still contains the familiar commands for opening and saving files. Other commands have been relocated onto a set of ribbon tabs, with the most frequently used commands together on the Home tab. I am used to the old options, where do I find the current location of any of the commands from previous versions? | Solution: In the help there is a map of the old commands in V7.3 and earlier to the new commands in the ribbon.
To find it, simply, go to the Getting Started tab of the ribbon and click on Ribbon Mapping. This links to the Help Contents | What's New in Aspen Plus V7.3.2 | Mapping Commands to the Ribbon topic.
This list is also attached as a .pdf.
Keywords: navigation, user interface, popular commands, ribbon
References: None |
Problem Statement: When using a RBATCH reactor and you try to export an input file with a continuous feed input from a previous Aspen Plus version, for example V7.3 the following error message is shown in the control panel: | Solution: The issue when you try to export an input file with a continuous feed input from a previous A+ version is related to an invalid set of units in that previous version, located under RBATCH (model name) | Setup | Continuous Feeds | ‘Specify flow vs time profile’. On the new GUI (Graphical User Interface), there are no units input for continuous feed time. Therefore, changing the Unit Sets to ENG for example in the new version GUI and redefined the values of time and flow again, it may help to make the simulation converge without problems (see screenshots below):
- Previous Unit Sets (User defined):
- Changing to ENG unit sets:
(Reset the original values of Time vs Flow):
Keywords: RBATCH, Error Message, Unit Sets.
References: None |
Problem Statement: My HEATX heat exchanger is bypassed. The error is
Block: BOILER Model: HEATX
** ERROR WHILE GENERATING RESULTS FOR UNIT OPERATIONS BLOCK: BOILER
(MODEL: HEATX)
COLD STREAM IS HOTTER THAN HOT STREAM
BLOCK BYPASSED | Solution: The problem in this file is that the cold stream was connected to the hot stream port of the HEATX rather than the cold stream port.
To solve this problem, the connections need to be reversed by disconnecting and reconnecting them to the correct port. If you hover over the port on the block, a pop-up help box with the name of the port type will appear.
Note that the reverse case is also a problem:
** ERROR WHILE GENERATING RESULTS FOR UNIT OPERATIONS BLOCK: HEATX
(MODEL: HEATX)
HOT STREAM IS COLDER THAN COLD STREAM
BLOCK BYPASSED
The procedure explained above also applies for this case.
Keywords: Heatx, hot port, cold port, block bypassed
References: None |
Problem Statement: When using a Heat exchanger in countercurrent and using the Hot/Cold outlet temperature approach I am observing convergence problems. | Solution: If the heat exchanger is in countercurrent and you use the Hot/Cold outlet temperature specification, the simulator is going to have a hard time estimating the possible results, particularly during initial iterations, which could cause convergence problems for the block.
This is because this specification is not providing good information for the simulator to reach aSolution, particularly if you are involving chemistry sets that change the equilibrium of the components and consequently the properties of the fluid in the heat exchanger.
Using an outlet temperature specification or an outlet/inlet temperature approach should provide better estimations for the heat exchanger to solve.
Keywords: HeatX, Hot/Cold outlet temperature approach, Aspen Plus, Countercurrent, convergence.
References: None |
Problem Statement: When opening a newer file in an older version, all of the databanks are missing | Solution: With the most recent patches, it is possible to open newer version such as V8.4 in V8.2, V8.0, or even V7.3. You will get a message about the file being created in a newer version. New features will, of course, be lost.
The problem is that if you used the Aspen Properties Enterprise Database (APED), the properties databanks are not selected since the older version does not recognize the newer APED databases such as APV84. Databanks must be re-selected. Binary databanks are lost in a way that the parameters do not appear on the forms even after they are re-selected.
However, if you used legacy databanks in the newer version, you can open the file in older versions without losing any of the databanks that existed in the older version. The older version can use either legacy databanks or APED. To use legacy databanks, go to Start -> All Programs -> AspenTech -> Process Modeling V8.x -> Aspen Properties -> Database Selector and select Legacy. If the new file uses PURE25 for the pure component properties, it can be opened in versions as old as V7.3.
Keywords: None
References: None |
Problem Statement: I am unable to run economic evaluation in Aspen Plus V7.3.2.
I run Aspen v7.3.2 model, then activate Economics. After finishing mapping, the icons remain grey out (Figure 1) and can't see results of economic analysis or proceed any further. I have installed Economic Evaluation V7.3 on machine.
Figure 1. Aspen Plus V7.3.2 Economics GUI. | Solution: This happens because Economic Evaluation V7.3.2 suite is not installed on machine. Economics Evaluation suite version should match the Aspen Plus version in order to have this functionality to work.
Install economics Evaluation V7.3.2 on machine and you will be able to complete economic analysis in Aspen
Plus V7.3.2
Keywords: Economics evaluation, Aspen Capital Cost Estimator, Aspen In-Plant Cost Estimator, Aspen Process Economic Analyzer.
References: None |
Problem Statement: Is a chemical reaction involving no-nconventional components allowed in an RGIBBS reactor? | Solution: The only physical properties that are calculated for nonconventional components are enthalpy and density. As quoted in the Getting Started manual, the RGIBBS reactor models chemical equilibrium by minimizing Gibbs Free energy. The Gibbs free energy of nonconventional components are not calculated.
Therefore, the RGIBBS reactor can not model the reaction of non-conventional components.
Alternatively, the RSTOIC or RYIELD reactor (seeSolution 123855) can be used for chemical reactions involving nonconventional components.
Â
Keywords: nonconventional components, RGIBBS, reaction
References: None |
Problem Statement: How to calculate additional properties for streams within hierarchy blocks. | Solution: In some cases it is necessary to calculate additional properties for streams only inside Hierarchy blocks.
There are two options to do that:
1. Â Open Blocks| Hierarchy_block_name| Setup| Report Option folder| Stream sheet and add additional Property Sets which include properties to report, as shown in the screenshot below:
It will override settings from the top-level Setup forms, and the results of selected property sets will be available in the Hierarchy streams only, but selected properties names will be displayed also for Stream Results in a Main Flowsheet.
Make sure that “Generate a standard stream report� option is checked, as then the Property Sets button will be active.
2. If you only want to see property sets for certain streams, the Custom Stream Summary option can be used. To do that:
a) In the Blocks| Hierarchy_block_name| Result Summary| Streams (Custom), right-click the Default tab and select Add to create a new tab.
b) Right-click that tab, and select Edit View.
c) On the Stream Selection tab, select streams to display.
d) On the Property Selection tab, click Add Property Set button, select a property set, and then select properties from that property set and click > to add them to the Selected Properties list.
e) Click OK.
Please note that in this case, the property will be added only to the selected Custom Streams folder, not to the report in each stream and block inside hierarchy.
Keywords: hierarchy, report, property sets
References: None |
Problem Statement: What does the following error mean and what can I do to solve it when working with RCSTR, FPlug or RBatch?
* WARNING REACTION RATE IS GREATER THAN ZERO FOR REACTION (X) BUT REACTANT X IS NOT PRESENT. POSSIBLE CAUSE: ZEROTH ORDER REACTANT NOT PRESENT
** ERROR M-BAL LOOP DID NOT CONVERGE | Solution: This error commonly occurs when the driving force term for the kinetic reaction has not been defined (the exponents for the rate equation have not been entered, see picture below). In this case a zeroth order is assumed for all reactants. This means that the reaction will continue even when one of the reactants has been fully depleted. There is mass destruction which triggers the inconsistency warning during calculations. This is why we get the mass balance convergence failure and, therefore, the error.
In order to solve the problem, please check that you have fully specified all the orders of reaction.
Keywords: Aspen Plus, RCSTR, FPlug, RBatch, Kinetic reaction, Zeroth Order, Reactant not present,
References: None |
Problem Statement: When using an Aspen HYSYS property method such as HYSPR in Aspen Plus, the density predicted for water is too way high. | Solution: When using the HYSYS property methods such as HYSPR or HYSSRK, it is recommended that the HYSYS property databank be selected first.
For a case of a pure water stream at 300 psia, there is almost a 25% difference between either HYSPR or HYSSRK and the Steam Tables (STEAMNBS) if HYSYS is not selected as the first databank. With the HYSYS databank, the difference is 1 to 2%.
STEAMNBS
HYSPR
HYSPR
with HYSYS databank
HYSSRK
HYSSRK
with HYSYS databank
TEMP
TOTAL
TOTAL
% difference
TOTAL
% difference
TOTAL
% difference
TOTAL
% difference
Â
RHOMX
RHOMX
RHOMX
RHOMX
RHOMX
F
gm/cc
gm/cc
gm/cc
gm/cc
gm/cc
200
0.9639869
1.202255
-24.72
0.9543146
1.00
1.202103
-24.70
0.9543117
1.00
225
0.9540223
1.183861
-24.09
0.9426921
1.19
1.1837
-24.07
0.9426873
1.19
250
0.9431916
1.165129
-23.53
0.9307553
1.32
1.164958
-23.51
0.9307477
1.32
275
0.9315167
1.146019
-23.03
0.9184624
1.40
1.145837
-23.01
0.9184509
1.40
300
0.9189995
1.126486
-22.58
0.9057632
1.44
1.126292
-22.56
0.9057462
1.44
325
0.9056216
1.106475
-22.18
0.8925961
1.44
1.106267
-22.16
0.8925719
1.44
350
0.8913432
1.085919
-21.83
0.8788853
1.40
1.085696
-21.80
0.8788516
1.40
375
0.8760996
1.06474
-21.53
0.8645348
1.32
1.064499
-21.50
0.8644889
1.33
400
0.8597964
1.042836
-21.29
0.8494203
1.21
1.042575
-21.26
0.8493589
1.21
Keywords: RHO, RHOMX, VL, VLMX
density
molar volume
References: None |
Problem Statement: Which correlations are used in the HCJ1BOIE enthalpy model for NC Solids? What does the option code allow to select? | Solution: The HCJ1BOIE enthalpy model can be selected from the Property environment, Methods | NC Props sheet. When selecting HCJ1BOIE, as shown in the image below, there is only one option code that one needs to specify. This option code refers to the Heat capacity correlation. The 2 codes that can be specified are:
1. Kirov correlation;
2. Cubic temperature equation.
The details of the correlations are reported at the topic ‘General Coal Enthalpy Model’ in the Aspen Plus Help.
Furthermore, the HCJ1BOIE model uses the following correlations:
· The Boie correlation for heat of combustion;
· The heat-of-combustion-based heat of formation correlation;
· Elements as enthalpy basis.
Then, the HCJ1BOIE enthalpy method is similar to HCOALGEN with the first, second and fourth option codes set to 1. See the following table which reports the HCOALGEN correlations according to the option codes that one can select.
For more information regarding each correlation, see topic ‘General Coal Enthalpy Model’ in the Aspen Plus Help.
Keywords: HCJ1BOIE, Option codes, NC Solid Enthalpy
References: None |
Problem Statement: After deleting a component, I cannot run because many property parameter forms are now incomplete. | Solution: After deleting a component, parameter data for that component is also deleted. When retrieved parameter data is deleted some forms or columns could be left empty. Aspen Plus does not delete the forms automatically to make sure that it does not inadvertently delete any data.
If you go to “Clean Parameters” from the Tools section of the ribbon and select “Purge incomplete property parameters and empty records” these will be deleted.
Keywords: None
References: None |
Problem Statement: Is there any way to get AspenPlus to calculate and set automatically the required amount of air that is needed for stoichiometric combustion? | Solution: A simpleSolution is to use a DesignSpec and to vary the oxygen inlet until combustion is complete.
As an example suppose we have carbon and hydrogen being fed into a Gibbs reactor and it is required to calculate the stoichiometric oxygen requirement for combustion of inlet carbon and hydrogen into carbon dioxide and water respectively. In the DesignSpec define form create three variables such as O2OUT, CARBON and HYDROG as stream variables to represent the molar flow rate of oxygen, carbon and hydrogen in the product stream out of the reactor. In the VARY form vary the molar flow rate of Oxygen in the inlet air stream and specify reasonable lower and upper bounds. Instead of RGibbs block an RStoic block with option to generate combustion reactions can be used
In the Fortran form write the following Statement
combust=carbon+hydrog+o2out
In the SPEC form specify the variable combust to be equal to zero. Using only the remaining oxygen flow rate of the outlet stream in the design specification target would not work correctly because any feed flow with insufficient oxygen would look as aSolution to the solver.
Keywords: minimum air flow, DesignSpec
References: None |
Problem Statement: I am migrating my V7.1 models to V7.3. The files that I ran in 7.1 gave results that I expected, but the same files in V7.3 gave strange and substantially different results, even while keeping the same V7.1 databases. I am suspicious that the problem may somehow be associated with some of my components (solids) since there does not seems to be much difference between V7.1 and V7.3 results when these components are not present. | Solution: This is a compatibility issue resulting from the way Aspen Plus V7.3 handles solid type components compared with versions V7.2 and earlier.
This is documented on Aspen Plus/ Help/ What?s new in Aspen Plus V7.3 (Figure 1)
Figure 1. Aspen Plus/ Help/ What?s new in Aspen Plus V7.3
In V7.3, components marked as solids on the components specifications sheet are treated differently than in previous versions of Aspen Plus.
In V7.2 and earlier, the liquid and vapor property models are used to calculate properties of solids included on MIXED substreams. In V7.3 and later, solid property models are used to calculate properties of solids.
In simulations, if there are some components specified as solid (Figure 2) which are present in MIXED substreams (Figure 3), those components can have very different properties in V7.3 using the solid property models than in V7.2 and earlier which used liquid and vapor property models. Since these components are marked as solids in the component form, it is likely that using the solids models will results in more accurate properties.
Figure 2. Aspen Plus Component specifications GUI
Figure 3. Aspen Plus Stream specifications GUI
If user wants to have dissolved solids in the MIXED sub stream along with solids, two components should be specified (one solid and one conventional).
If there is no solid formation expected for user solid components, they should be just defined as conventional components in V7.3. The modified V7.3 file will then match the results obtained by its V7.1 counterpart using this methodology.
Keywords: Solids, Upward compatibility.
References: None |
Problem Statement: Is it possible to have a component be both a salt and an apparent component that dissociates using electrolyte chemistry? | Solution: It was possible in earlier versions to one component be both a salt and an apparent component though it was not recommended. Now, in V7.3 and later, two components should always be specified since components with a type of solid are calculated using solid property parameter models. The salt should be specified as a component of type solid and the apparent component should be specified with a type of conventional.
The Chemistry will include both the dissociation and the salt reactions.
Keywords: None
References: None |
Problem Statement: When specifying that the solid substream for a RPlug reactor is at a different temperature, do you need a user kinetic subroutine? If so why? Can you give some guidance as to how to use this feature? | Solution: In V8.6 and earlier, if you specify the substreams are at different temperatures, you must supply a user kinetic subroutine. This subroutine must calculate FLUXM and FLUXS, the rates of components transferred between substreams, in order for Aspen Plus to properly calculate the enthalpy of each substream (accounting for the enthalpy change associated with the transferred material).
Note that any unit operations that perform a flash will equalize the substream temperatures.
Many blocks will flash the inlet streams, outlet streams, or both. If you mean to maintain the solids at a different temperature than the fluid phases, you should separate the substreams into separate streams in an SSplit block before feeding the stream through any block that performs a flash.
If you specify the substreams are at different temperatures and you do not supply a user kinetic subroutine, RPlug assumes all reactions which involve both solid substream and MIXED substream components occur in the solid phase. This means that the reactions occur at the temperature of the solid substream(s) and any heat of reaction affects the enthalpy of the solid substream(s). If you do specify a kinetic subroutine, the subroutine determines where the reactions occur and sets FLUXM and FLUXS and the reaction rates appropriately. See chapter 11 of Aspen Plus User Models for more information about the kinetic subroutine.
Keywords: None
References: : CQ00534838 |
Problem Statement: I received an Aspen Plus simulation with a custom table. The names of the variables in the custom table do not indicate how to find them in the simulation. How can I identify the path of this variables to its unit operation? | Solution: If you right click in one of the headings of the custom table, a contextual menu will be shown, see image below:
Select the option choose columns:
You will be able to add the variable name and the path as a column to the custom table.
This way you will be able to see easily the path to the variable and locate them in the simulation
Keywords: custom table, variable path
References: None |
Problem Statement: Where can I find Unit-set option for results in new Aspen Plus V7.3.2 GUI?. I could not find the Output Results unit option in V7.3.2, but here is a screenshot of the old version: | Solution: You still select the global units of measure on the Setup | Specifications | Global sheet.
It can also be selected on the Units section of the Home ribbon.
The difference is that there is only one global unit set now rather than Input and Output units.
In V7.3 and earlier:
Units of measure were set at three levels
Global (default units)
Object-level (i.e. block, stream, etc.)
Field (individual input)
Users can create new unit sets based on existing unit sets; however, they cannot modify built-in units of measurement sets or modify user-created units of measurement sets once used by an object. A new unit set must be created for different units combinations.
In V7.3.2 and higher, Units in Aspen Plus can be defined only at two different levels:
Global Level on the Home ribbon Units group
Field Level
Users can create their own unit sets by clicking the Unit Sets icon on the Home ribbon. Units can be copied from an existing set and then modified. Any unit set except ENG, SI and Metric can be changed. Editing of current Global units is also allowed though you must select another unit set before modifying.
Same Global unit set for Input Data and Output Results.
Changing the Global units set updates ALL values to the new units and converts the values appropriately except for these forms (Fields for these objects cannot have units specified directly):
Calculator
Sensitivity
Estimation
Design-Spec
Parameters
Pres-Relief
Optimization
Data
Constraint
Tabpoly
Data-Fit
Generic property analysis
Object-level units field is retained for these objects and now appears on the Information sheet for the object. Object level units are converted to global units on opening previous version BKP files (except for above forms)
Keywords: None
References: None |
Problem Statement: Which flooding calculation method is used by Aspen Plus by default in a RadFrac block when none is specified by the user for tray sizing? | Solution: By default when the user does not specify any method for flooding calculations in a RadFrac model for tray sizing:
Aspen Plus uses Glitsch calculation method as default. This can be checked under the ‘Report’ which can be generated from the simulation environment Home (ribbon) | Summary (group) | Report. Within this report, under ‘TRAY SIZING CALCULATIONS’, it can be confirmed that the ‘Glitsch’ method is used for flooding calculations (column diameter) when any method is selected by the user (when this field is left in blank). An example of this report is shown below:
************************************
***** TRAY SIZING CALCULATIONS *****
************************************
*******************
*** SECTION 1 ***
*******************
STARTING STAGE NUMBER 2
ENDING STAGE NUMBER 14
FLOODING CALCULATION METHOD GLITSCH
DESIGN PARAMETERS
-----------------
Keywords: RadFrac, Tray Sizing, Flooding Calculations, Report, Glitsch Method.
References: None |
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