$.$ Carbon dioxide $($along with other gases$)$ has been implicated in global warming. A process is

being developed which will separate CO$2$ from flu gas in a coal fired power plant and

subsequently sequester the CO$2$ underground. A schematic of the proposed process is shown

below.

RO unit

$1500$ lb$/$hr

$96\mathrm{.}9$ wt$\%$ water

$3\mathrm{.}1$ wt$\%$ salt

Brine recycle $($m$2$

$)$

Desalinized water $($m$4$

$)$

$500$ ppm $($by mass$)$ salt

m$3$

$4\mathrm{.}0$ wt$\%$ salt

m$5$ Brine waste $($m$6$

$)$

$5\mathrm{.}25$ wt$\%$ salt

RO unit

$1500$ lb$/$hr

$96\mathrm{.}9$ wt$\%$ water

$3\mathrm{.}1$ wt$\%$ salt

Brine recycle $($m$2$

$)$

Desalinized water $($m$4$

$)$

$500$ ppm $($by mass$)$ salt

m$3$

$4\mathrm{.}0$ wt$\%$ salt

m$5$ Brine waste $($m$6$

$)$

$5\mathrm{.}25$ wt$\%$ salt

RO unit

$1500$ lb$/$hr

$96\mathrm{.}9$ wt$\%$ water

$3\mathrm{.}1$ wt$\%$ salt Desalinized water $($m$4$

$)$

Brine waste $($m$6$

$)$

RO unit

$1500$ lb$/$hr

$96\mathrm{.}9$ wt$\%$ water

$3\mathrm{.}1$ wt$\%$ salt Desalinized water $($m$4$

$)$

Brine waste $($m$6$

$)$

A cleaned and dry flu stream $($m$1),$ comprised of $26$ wt$\%$ CO$2$ and $74$ wt$\%$ N$2,$ enters into an

absorber at a flow rate of $5\mathrm{.}0\backslash$times $104$

kg$/$hr where it contacts liquid$-$phase amine solvent

$($MEA$)$ in an absorber$.$ The amine solvent selectively absorbs CO$2.$ The flu gas stream

exiting the absorber $($m$2)$ is composed of $98$ wt$\%$ N$2$ and $2\mathrm{.}0$ wt$\%$ CO$2.$ The liquid stream

exiting the absorber $($m$3)$ contains only amine and CO$2.$ The liquid stream is subsequently

fed to a stripper where it is heated and $95\%$ of the available CO$2$ is desorbed from the amine.

The CO$2$ exiting the stripper $($m$4)$ is subsequently pressurized and injected into subterranean

rock formations. The MEA exiting the stripper $($m$5),$ comprised of $99$ wt$\%$ amine and $1\mathrm{.}0$

wt$\%$ CO$2,$ is recycled back into the absorber$.$

a$)$ What percent of the CO$2$ in stream m$1$ is removed?

b$)$ What is the concentration $($in wt$\%)$ of CO$2$ in stream m$3?$

c$)$ What is the flow rate $($in kg$/$hr$)$ of the recycle stream $($m$5)?$

d$)$ Tests conducted on experimental apparatus reveal that there will actually be a trace

amount of amine in the pure CO$2$ stream. If the concentration of amine in stream m$4$ is

actually $25$ ppm $($not $0$ as the figure shows$)$ determine the required flow rate of make$-$up

MEA $($in kg$/$hr$)$ required in the process. For part d$)$ please assume that the total flow rate

of m$4$ to be $15,000$ kg$/$hr$.$