Solution:
A reactor system is to be designed for $85 \%$ conversion of $A$ in a second–order liquid–phase reaction, $A \to $ products; $k_A = 0.075\ L\ mol^{-1} min^{-1}$, $v_0 = 25\ L\ min^{-1}$ (volumetric flow rate), and $C_{A0} = 0.04\ mol\ L^{-1}$. The cost of a vessel is \$ $0.29\ L^{-1}$, but a $10\ \%$ discount applies if both vessels are of the same size and geometry. The design options are :
\begin{parts}
\part [11] two equal–sized stirred tanks in series; what is the capital cost of this design?
\part [11] two stirred tanks in series to provide a minimum total volume; what is the capital cost of this design?
\end{parts}
(Hint : the solutions may be obtained by trial \& error.)
