Soybean protein concentrate contains $65\%$ water, after extraction. It is pressed in a shape

of slab $15103cm$ and dried by exposing both sides of the slab to air at $1$atm and $65C,$

containing $0\mathrm{.}01kg$ water $\frac{?}{kg}$ dry air across the faces of the slab at $3\frac{m}{s}.$ The critical

moisture content is $50\%$ and the equilibrium moisture content is $5\%.$ After $50\%$ moisture

content is reached diffusion will control. Assuming that the moisture distribution in the

slab is uniform when average moisture content is at $50\%,$ calculate the time required to

reduce the moisture content from $65$ to $10\%.$ The density of the extract is $1\mathrm{.}5g\frac{r}{c}{m}^3.$

The diffusivity of water in soybean concentrate is $2{10}^{-5}\frac{m^2}{h}r.$