Consider a three-stage evaporator operating in fonward feed mode, 1000 kg/h of 1.0 wt % NaCl in water is being concentrated using steam at 150C. The final stage is operating at a temperature and pressure of 50C and 12.35 kPa, respectively. The overall heat transfer coefficients of stages 1, 2, and 3, are 3000, 2000, and 1500 W/m? K respectively. The heat of mixing and boiling point rise of the solution can be assumed to be negligible. The latent heat of steam (kJ/kg) as a function of temperature (C) for this temperature range is: AHvaP = - 2.679T + 2520.7. a) Assuming the heat transfer area of each stage is the same, determine the temperatures of stages 1 and 2. b) If the steam flow rate, S, is 100 kg/h, determine the liquid and vapor flow rates of each stage. Ignore sensible heat effects. c) What is the final concentration of salt leaving the evaporator? d) What is the overall steam economy