EXAMPLE $9\mathrm{.}5$ OPTIMUM MIXED FLOW REACTOR PERFORMANCE A concentrated aqueous A$-$solution of the previous examples $($CAo$4$ mol$/$liter$,$ FA$0-1000$ mol$/$min$)$ is to be $80\%$ converted in a mixed flow reactor. $($a$)$ What size of reactor is needed? $($b$)$ What is the heat duty if feed enters at $25$C and product is to be withdrawn at this temperature? Note that $1000$ cal $1$kg $1$ liter kg K $1$ iter $4$mol Amol A K cal $-=250$ SOLUTION $($a$)$ Reactor Volume. For Co $4$ moliter we may use the XA versus T chart of Fig. E$9\mathrm{.}3$ as long as we multiply all rate values on this chart by $4$ Following Fig. $9\mathrm{.}9$ the mixed flow operating point should be located where the locus of optima intersects the $80\%$ conversion line $($point C on Fig. E$9$Sa$).$ Here the reaction rate has the value $-?=0\mathrm{.}4$ mol A converted$/$min $.$ liter From the performance equation for mixed flow reactors, Eq$.5\mathrm{.}11,$ the volume required is given by FAOXA $(1000$ mol$/$min$)(0\mathrm{.}80)($rA $0\mathrm{.}4$ mol$/$min liter $-2000$ liters