A hot air at a wet$-$bulb temperature of $34C$ and $5\%RH$ is introduced to a tray dryer at a

flow rate of $720\frac{m^3}{h}r$ for drying fresh soybean cakes $(1,800kg)$ with $400\%M{C}_{db}.$ At the

end of the constant$-$rate period, the moisture content of the soybean cakes reaches $60\%$ wet

basis.

$($a$)$ Determine the amount of water removed by the critical moisture content.

$($b$)$ Determine the mass $($in $kg)$ of dry air introduced into the dryer per hour..