$80,000$ lb$/$h of a $10\%$ soda solution in water will be concentrated to $50\%.$ Water vapor available at $100$ psia and $340º$F will be used. The third evaporator has a pressure of $2$ psia. The three counterflow evaporators are the same size with approximate U values $$of $350,400,$ and $450$ BTU$/$h $º$F ft$^2$ for the $1$st$,2$nd$,$ and $3$rd evaporators, respectively. The feeding of soda in water is carried out at $100º$F$.$

Look for the area of $$the evaporators as well as the live steam consumption.