The following table shows the meaning of the variables appearing in this tab, as well as their default values and their generally acceptable range. Note that due to the manner by which the variables are used by the sizing and costing equations, the range of acceptable values may be further reduced.
|
Variable |
Default Value |
Range |
|
|
||
|
◙ Volume |
1,000.0 L |
Positive |
|
◙ Max Volume |
80,000 L |
Positive |
|
○ Min Allowable Working/Vessel Volume |
0% |
[0,99] |
|
○ Max Allowable Working/Vessel Volume |
90% |
(0,99] |
|
● Length |
0 m |
Positive |
|
● Diameter |
0 m |
Positive |
|
○ Length/Diameter |
3.0 |
Positive |
|
○ Equipment Heat Capacity |
0 kcal/°C |
Positive. |
|
○ Is ASME Vessel? |
Yes |
Yes/No |
|
○ On Wheels |
No |
Yes/No |
|
○ Mixing |
No |
Yes/No |
Symbol Key: ○ User-specified value (always input); ● Calculated value (always output); ◙ Sometimes input, sometimes output
In design mode, the user specifies the max volume, and the program calculates the number of units and volume based on the volume demand that is specified by the operations carried out as part of the (one or more) unit procedures hosted by the equipment resource. Typically, even during the span of a single procedure, more than one operations may demand different volumes. The software will size the vessel based on the largest demand on vessel volume amongst all operations executed in the vessel. If that volume exceeds the maximum volume specification then the software will assume multiple number of identical units, each with a volume that does not exceed the max volume specification, so that the total volume is equal to the demand. From the vessel volume and the height-diameter aspect ratio, the actual dimensions of each vessel (height and diameter) are calculated.
Depending on the unit procedure’s nature (batch vs continuous), the demand on vessel volume by each operation is calculated as follows: If the unit procedure is batch (e.g., Batch Vessel Procedure in a Reactor), then for each operation the demand on liquid volume is divided by the operation’s max allowable working to vessel volume ratio to determine the operation’s demand on vessel volume. In that case, the equipment’s min and max allowable working to vessel volume ratio limits act as constraints on the operation’s min and max allowable working to vessel volume ratio limits (i.e., the operation’s min and max working to vessel volume ratio limits must be within the range defined by the equipment’s min and max working to vessel volume ratio limits). If the unit procedure is continuous (e.g., Continuous Stoichiometric Reaction in a CSTR), then for each operation the demand on liquid volume is divided by the operation’s working to vessel volume ratio to determine the operation’s demand on vessel volume. In that case, the equipment’s min and max allowable working to vessel volume ratio limits act as constraints on the operation’s working to vessel volume ratio (i.e., the operation’s working to vessel volume ratio must be within the range defined by the equipment’s min and max working to vessel volume ratio limits).
For more information on the sizing of a blending tank, see Batch Storage: Modeling Calculations and Continuous Storage: Modeling Calculations.
In rating mode, the volume of the vessel and the number of units are provided by the user. As in the design mode case, the actual dimensions of each vessel (height and diameter) are calculated from the vessel volume and the height-diameter aspect ratio. The program also calculates exactly as in the design mode case the demand on vessel volume by the operations carried out as part of the unit procedure(s) hosted by the equipment resource, and if any operation’s vessel volume demand of exceeds the actual vessel volume, it generates a warning.
Equipment purchase cost is based on total vessel volume and material of construction. If the vessel is checked as an ‘ASME Vessel’ (i.e., constructed according to standards published by the American Society of Mechanical Engineers) then it is assumed to withstand pressure to 35 psig and its purchase cost is penalized by 20% over the base vessel cost. If the operating pressure of the vessel is set to a pressure higher than 3 atm, then the vessel’s purchase cost is penalized by an 80% increase over the base cost.
Checking “On Wheels” will add wheels to the unit procedure icon. Checking “Mixing” will add an agitator to the unit procedure icon. In addition, if a Batch Storage in a Horizontal Tank Procedure is used, checking "Mixing" will also enable the "Agitate" operation to become available as an option in the dialog shown when the user clicks on the unit procedure’s “Add/Remove Operations” context menu option.
For more information on this equipment, see Horizontal Tank.
For information on the left-hand side variables and options, see Equipment Data Dialog: Equipment tab.