The evaporation of feedwater at 100°C into dry and saturated steam at 100°C at atmospheric pressure is known as ______.

Explanation:

Equivalent evaporation: It is defined as the amount of dry and saturated steam generated from feed water at 100°C at normal atmospheric pressure.

\({\rm{Equivalent\;evaporation}} = \frac{{{\rm{Mass\;of\;steam\;generated\;per\;hour}} ~\times~ {\rm{Heat\;supplied\;to\;steam\;in\;boiler}}}}{{{\rm{Heat\;supplied\;for\;steam\;generation\;at\;}}100^\circ {\rm{C\;from\;water\;at\;}}100^\circ {\rm{C\;}}\left( {{\rm{i}}.{\rm{e}}.{\rm{\;Latent\;heat}}} \right)}}\)

\({\rm{Equivalent\;evaporation\;of\;the\;boiler}} = \frac{{{{\dot m}_s}\left( {{\rm{h}} - {{\rm{h}}_{\rm{f}}}} \right)}}{{{\rm{enthalpy\;of\;evaporation\;of\;water\;at\;}}100^\circ {\rm{C}}}}\)

ṁ­s = Mass of steam output

h = enthalpy of steam at the exit of the boiler

hf = enthalpy of feed-water at the inlet of the boiler

The enthalpy of evaporation of water at 100°C = 2257 kJ/kg

 \(The ~equivalent ~evaporation =\frac{{Total\;heat\;required\;to\;evaporate\;feed\;water}}{{2257}}\)