A forced circulation triple-effect evaporator using forward feed is to be used to concentrate a 10wt% NaOH solution entering at 37.8oC to 50wt%. The steam used enter at 58.6KPa gage. The absolute pressure in the vapor space of the third effect is 6.76KPa. The feed rate is 13608kg/h ,heat transfer coefficient are U1=6246,U2=3407 and U3=2271 W/m2.K.All effect have the same area ,Calculate the surface area required and steam consumption