$1.$ For a production process, a triple$-$effect evaporator with direct feed is required; It will be used to concentrate a $20\%$ to $70\%$ sodium hydroxide solution. A stream of $70,000$ lb$/$h is fed from an atmospheric storage tank $($T$=77$F$)$; the vapor in the last effect is condensed at $120$F$.$ The values $$of the global heat coefficients $700,800$ and $1000$ Btu$/$ft$2$ h $$F for effects I, II and III. Calculate the values $$of the transfer area required for each effect, considering that they will all have the same area. The amount of heating steam, if the service area provides saturated steam at $173\mathrm{.}23$ psia; and the economy of the evaporator system.

If you want to increase the economy of this evaporation system, what alternatives would you propose to achieve this?

Draw the process flow diagram $($PFD$)$