For a production process, a triple$-$effect evaporator with reverse feeding 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$-55\backslash$deg C$),$ the vapor in the last effect is condensed at $120\backslash$deg F$.$ The values $$of the global heat coefficients $700,800$ and $1000$ Btu$/$ft h$\backslash$deg F for effects I, II and III. Calculate the values $$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

evaporator system. If the economy of this evaporation system is increased, what alternatives would you propose to achieve this?