Problem $2$: $18$ points

a$.(4$ points$)$ Review example $3\mathrm{.}15.$ Explain how to determine which reactor type

$($batch$,$ CMFR$,$ or PFR$)$ is being applied in this example. Is this a correct model?

Explain why it is correct or incorrect.

b$.(14$ points$)$ The water quality in Lake Silbersee has been diminished by the

production of hydrogen sulfide $(H_2(S)).$ It is proposed to aerate the lake. Aeration

halts the production of $H_{2}S$ and oxidizes $H_{2}S.$ The kinetic rate expression for

oxidation is shown in example $3\mathrm{.}15.$ To model the process in a pilot plant, a

reactor $(750m^3)$ operated as a CMFR$,$ and containing lake water, is aerated until

the dissolved oxygen concentration is $2m\frac{g}{L},$ at which point production of $H_{2}S$

stops. When production of $H_{2}S$ stops, this is $t=0,$ and $[H_2(S)]=500M.$ The inlet

No portion of this assignment, nor solutions, may be shared with anyone outside of the registered

roster of students in this year's class.

and outlet flows are $50\frac{m^3}{?}$ day and aeration continues. How long does it take the

concentration of $H_2(S)$ to reach $100M?$ Water entering the CMFR does not

contain $H_{2}S.$