$6.$Its required to concentrate black liquor in vertical long tube evaporator. The liquor is fed to the evaporator at $10k\frac{g}{s}.$ The feed liquor contains $25\%$ solids. From the evaporation unit, two streams emerge. In the first stream the liquor is found to contains $42\%$ solids $($concentrate$).$ Te second stream is pure vapor $($Water$)$

$6\mathrm{.}1$ Draw and completely label the process

$6\mathrm{.}2.$ Write all the applicable equations and determine the mass flow of black liquor and vapor $($water$)$ from the bottom and top streams