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 |
|
|
||
|
○ Operates as Electrolyzer |
False |
True/False |
|
● Eletrode Name |
Dft Cathode |
Any |
|
● Electrode Width |
0.980 m |
Positive |
|
● Electrode Height |
0.986 m |
Positive |
|
○ Max. Number of Cathodes |
60 |
Positive |
|
◙ Number of Cathodes |
60 |
Positive |
|
○ Number of Anodes - Number of Cathodes |
1 |
Zero or Positive |
|
● Total Cathode Active Area |
0 m2 |
Positive |
|
○ Spacing Between Cathodes |
0.10 m |
Positive |
|
◙ Cell Length |
6.0 m |
Positive |
|
◙ Cell Width |
0.980 m |
Positive |
|
◙ Cell Height |
0.986 m |
Positive |
|
● Cell Volume |
0 m2 |
Positive |
|
○ Max. Cell Cathode Active Area |
0.1 m2 |
Positive |
|
○ Number of Cells |
100 |
Positive |
|
◙ Cell Cathode Active Area |
0.0 m2 |
Positive |
Symbol Key: ○ User-specified value (always input); ● Calculated value (always output); ◙ Sometimes input, sometimes output
Unless “Operate As Electrolyzer” is selected, this equipment will require use of an ‘Electrode’ type consumable (actually, a set of consumables of this type). Each ‘Electrode’ consumable in the database (see Consumables Properties Dialog: Electrode Identification tab and Consumables Properties Dialog: Electrode Properties tab) has an ‘Electrode Type’ property that can be set to one of the following three values: ‘Cathode’, ‘Anode’, or ‘Electrode Pair’. If the selected electrode is of the ‘Cathode’ or ‘Electrode Pair’ type, then the required number of electrodes of this type is equal to the specified (in rating mode) or calculated (in design mode) Number of Cathodes. If the selected electrode is of the ‘Anode’ type, then the required number of electrodes of this type is equal to the Number of Cathodes plus the specified (Number of Anodes - Number of Cathodes).
Three different ‘Electrode’ consumables are predefined in the database, one for each electrode type: ‘Dft Cathode’ (whose ‘Electrode Type’ property is set to ‘Cathode’); ‘Dft Anode’ (whose ‘Electrode Type’ property is set to ‘Anode’); and ‘Dft Electrode Pair’ (whose ‘Electrode Type’ property is set to ‘Electrode Pair’). By default, the ‘Dft Cathode’ consumable is selected as the required consumable, and a ‘Dft Anode’ consumable is also added to the list of ‘Other Consumables’ (see Electrowinning Cell: Consumables tab). More ‘Electrode’ consumables can be easily added in the Consumables databank.
If “Operate As Electrolyzer” is not selected:
In Design Mode, the user specifies a number of inputs, including the specification of conversion of the reaction with respect to a particular reactant or the specification of the target concentration of a particular product, and based on these, the program calculates (mainly) the Number of Units and Number of Cathodes (per unit). More specifically:
Through the equipment data dialog, the user selects the required “Electrode” consumable (which can be of the cathode, anode or electrode pair type, depending on the specified “Electrode Type” property of the selected consumable), and also specifies the Maximum Number of Cathodes (per unit) as well as the Number of Anodes - Number of Cathodes.
Through the operation’s data dialog, the user also specifies the stoichiometry of the electrowinning reaction, the conversion with respect to a reference reactant or the concentration of a target product, the specification of recovered cathode and anode products, the source ion valencies of either the cathode or anode products, the current density, and the current voltage.
Based on the above data, the program first calculates the total cathode surface area requirement by the operation. In the case that this equipment is shared by many procedures, the total cathode surface area requirement is determined for the operation(s) carried out as part of the (one or more) unit procedure(s) hosted by the equipment resource. The software will size the cell based on the largest demand on total cathode surface area amongst all operations executed in the cell. Once the largest demand on total cathode surface area is determined, it is divided by the surface area of a single cathode (which is equal to 2 times the electrode width times the electrode height) to determine the required total number of cathodes. If that number is less than the specified Maximum Number of Cathodes, then the Number of Units is set equal to 1, and the Number of Cathodes is set equal to the required total number of cathodes. If, however, the required total number of cathodes exceeds the specified Maximum Number of Cathodes, then the total cathode surface area requirement is divided by the Maximum Number of Cathodes and by the surface area of a single cathode, and then it is rounded up to the nearest integer to determine the Number of Units. Subsequently, the required total number of cathodes is divided by the Number of Units, and then it is rounded up to the nearest integer to determine the Number of Cathodes (per unit).
After calculating the Number of Units and Number of Cathodes, the program will also calculate the Cell Length, Cell Width, Cell Height and Cell Volume. The Cell Length is assumed equal to the Number of Cathodes times the Spacing Between Cathodes. The Cell Width is assumed equal to the Electrode Width, and the Cell Height is assumed equal to the Electrode Height.
Finally, if the selected “Electrode” consumable is of the cathode type, and there is also an “Electrode” consumable of the anode type in the “Other Consumables” table, whose consumption rate is specified in items (i.e., anodes) per equipment unit, then the program will also calculate the number of anodes by adding the specified (Number of Anodes - Number of Cathodes) value to the Number of Cathodes, and then it will set the consumption rate of that consumable to be equal to the calculated number of anodes.
If “Operate As Electrolyzer” is selected:
In Design Mode, the user specifies the maximum cell cathode active area and the number of cells, and the program calculates the cell cathode active area and the number of units (cell stacks) based on the specified inputs through the equipment data dialog and through the operation data dialog.
If “Operate As Electrolyzer” is not selected:
In Rating Mode, the user specifies a number of inputs, including the size parameters of the cell, and based on these, the program calculates (mainly) the conversion of the reaction with respect to the limiting component. More specifically:
Through the equipment data dialog, the user selects the required “Electrode” consumable and specifies the Number of Cathodes, Number of Anodes - Number of Cathodes, Cell Length, Cell Width and Cell Height. A warning is displayed if the Electrode Width of the selected electrode exceeds the specified Cell Width or if the Electrode Height of the selected electrode exceeds the specified Cell Height.
Through the operation’s data dialog, the user also specifies the stoichiometry of the electrowinning reaction, the specification of recovered cathode and anode products, the source ion valencies of either the cathode or anode products, the current density, and the current voltage.
Based on the above data, the program calculates the conversion with respect to the limiting component, the conversion with respect to a reference reactant (optional), and the target concentration of a reference product component (optional).
Also, as in design mode, if the selected “Electrode” consumable is of the cathode type, and there is also an “Electrode” consumable of the anode type in the “Other Consumables” table, whose consumption rate is specified in items (i.e., anodes) per equipment unit, then the program will also calculate the number of anodes by adding the specified (Number of Anodes - Number of Cathodes) value to the Number of Cathodes, and then it will set the consumption rate of that consumable to be equal to the calculated number of anodes.
If “Operate As Electrolyzer” is selected:
In rating mode, the user specifies the number o units (cell stacks) and the cell cathode active area. The program calculates the required cell cathode active area (based on the specified inputs through the equipment data dialog and through the operation data dialog), and if this exceeds the specified (rated) cell cathode active area, it displays a warning.
If “Operate As Electrolyzer” is not selected:
The equipment’s built-in purchase cost is based on the cell’s volume. The built-in model is based on the available data in the literature regarding the cost of a horizontal tank. If the first set of selected “Electrode” consumables (cathodes, anodes or electrode pairs depending on the “Electrode Type” property), then the built-in equipment purchase cost will be the sum of the tank’s purchase cost and the cost of the selected set of “Electrode” consumables.
The equipment’s user-defined purchase cost is based on the cell’s total cathode area available, which is calculated by multiplying the cell width by the cell height and by two, and then multiplying by the number of cathodes.
If “Operate As Electrolyzer” is selected:
The equipment’s built-in purchase cost returns zero. The equipment’s user-defined purchase cost is based on the total active area of the cell stack, which is equal to the cell cathode active area times the number of cells.
For more information on this equipment, see Electrowinning Cell.
For information on the left-hand side variables and options, see Equipment Data Dialog: Equipment tab.