Dewatering Unit Costing Method
There are three classes of dewatering costing types (centrifuge, filter belt press, and filter plate press), each with their own parameters, variables, and costing relationships. The default configuration is a centrifuge, so users must manually change the dewatering type if they wish to invoke the costing method for filter belt press or filter plate press dewatering units.
Costing Method Parameters
The following parameters are constructed for the unit on the FlowsheetCostingBlock (e.g., m.fs.costing.dewatering) when applying the cost_dewatering costing method in the watertap_costing_package:
Description |
Symbol |
Parameter Name |
Default Value |
Units |
|---|---|---|---|---|
Centrifuge |
||||
Capital cost A parameter \(^1\) |
\(A_{centrifuge}\) |
|
328.03 |
\(\text{USD}_{2007}\text{/gal/hr}\) |
Capital cost B parameter \(^1\) |
\(B_{centrifuge}\) |
|
751295 |
\(\text{USD}_{2007}\) |
Filter belt press |
||||
Capital cost A parameter \(^1\) |
\(A_{fbp}\) |
|
146.29 |
\(\text{USD}_{2007}\text{/gal/hr}\) |
Capital cost B parameter \(^1\) |
\(B_{fbp}\) |
|
433972 |
\(\text{USD}_{2007}\) |
Filter plate press |
||||
Capital cost A parameter \(^1\) |
\(A_{fpp}\) |
|
102794 |
\(\text{USD}_{2007}\text{/gal/hr}\) |
Capital cost B parameter \(^1\) |
\(B_{fpp}\) |
|
0.4216 |
\(\text{USD}_{2007}\) |
Costing Method Variables
The following variables are constructed on the unit block (e.g., m.fs.unit.costing) when applying the cost_dewatering costing method in the watertap_costing_package:
Description |
Symbol |
Variable Name |
Index |
Units |
|---|---|---|---|---|
Inlet volumetric flow rate |
\(Q_{in}\) |
|
[t] |
\(\text{gal/hr}\) |
Capital Cost Calculations
Capital cost is dependent upon the volumetric flow rate, \(Q_{in}\), as shown in the equations below.
\[C_{cap,centrifuge} = A_{centrifuge} * Q_{in} + B_{centrifuge}\]\[C_{cap,fbp} = A_{fbp} * Q_{in} + B_{fbp}\]\[C_{cap,fpp} = A_{fpp} * Q_{in} + B_{fpp}\]
Operating Cost Calculations
Electricity \(C_{elec}\) is a variable operating cost based on the energy intensity \(E\) of the unit process (electricity consumption for the dewatering unit), electricity price \(P\), electricity flow \(Q\), and the plant utilization factor \(f_{util}\). The annual electricity costs are calculated as:
\[C_{op, tot} = C_{elec} = E Q f_{util} P\]
Code Documentation
References
[1] W. McGivney, S. Kawamura, Cost estimating manual for water treatment facilities, John Wiley & Sons, 2008. http://onlinelibrary.wiley.com/book/10.1002/9780470260036.