A 20% NaOH solution fed to a single effect evaporator at a flow rate of 9000 kg/hr is concentrated to contain 50% NaOH. The water vapor used for heating has an absolute pressure of 198.5 kPa. There is an absolute pressure of 13.3 kPa inside the evaporator and the total heat transfer coefficient is 1400 W/m2 ^oC. The specific heat of the superheated solvent vapor is 0.45 kJ/kg K. Since the feed temperature is 37.8 ^oC:

a) The amount of steam consumed (kg/hour) b) Steam economy c) Calculate the heat transfer area of the evaporator. (m2)