A forced-circulation evaporator is to concentrate 60,000 kg/h of 44 percent NaOH to 65 percent using steam at 3 atm pressure. The feed temperature and the condensing temperature are both 40°C. The density of the feed solution is 1,450 kg/m³. If the overall heat-transfer coefficient is 2,000 W/m². °C, calculate

(a) The steam requirement, in kilograms per hour;

(b) The heat-transfer area required.