Question

The cost of constructing a distillation column can be written
C = CpAN + CsHAN + Cf + Cd + Cb + CL + Cx
where
C= total cost
Cp= cost per square foot of plate area, $/ft2
A= column cross-sectional area, ft2
N= number of plates
Nmin= minimum number of of plates
Cs= cost of shell, $/ft2
H= distance between plates, ft
Cf= cost of feed pump, $
Cd= cost of distillate pump, $
Cb= cost of bottoms pump, $
2
CL= cost of reflux pump, $
Cx= other fixed costs, $
optimize the total cost