$(20\%)$ A gaseous waste stream is generated within a plastic film

processing operation from a drying step. The stream $(12,000scfm)$

is currently being vented to the atmosphere and it contains $0\mathrm{.}5\%$vol.

of total VOCs of equal amount of toluene and ethyl acetate. An

absorption column and a distillation column are proposed to recover

the toluene and ethyl acetate. In the absorption tower, tetradecane is

used as the absorption oil. $CO,C{O}_2,N{O}_2$ and $S{O}_2$ are emitted

from reboilers burning #$4$ heating oil. The recovery efficiency can

be improved by increasing the flow rate of absorption oil flow rate

$($i$.$e$.$ n$-$tetradeane flow rate$),$ which however, will increase the

energy requirement, leading to higher combustion emissions. A

waste audit based on process flowsheet estimates all pollutant

emission rates from the process as shown in Table $2$ for the base

case without solvent recovery, the case with $99\%$ toluene recovery,

and the case with $99\%$ reduction of both toluene and ethyl acetate.

a$.(10\%)$ Calculate the percentage reduction in overall global

warming impacts of the waste streams from this process for the

proposed options over one year period $(300$ days in operation$).$

Assuming all hydrocarbons are oxidized to $C{O}_2$ after their

releases, using IPCC$5{100}_y$ear $GWP$

b$.(10\%)$ Calculate the percentage reductions in non$-$carcinogenic

risks for both proposed options based on CHEMINFO web.

Assuming an intake fraction $($iF$)$ of $0\mathrm{.}01\%($i$.$e$.iF=0\mathrm{.}0001),$ and

the workers exposed to the polluted air over their $8-$hour work

shift each day.

Table $2.$ Air emission rates of chemicals from a solvent recovery

process.