8.4-1. Heat-Transfer Coefficient in a Single-Effect Evaporator. A feed of 4535kg/h of a 2.0 wt. \% salt solution at 311K enters continuously a single-effect evaporator and is concentrated to 3.0%. The evaporation is at atmospheric pressure and the area of the evaporator is 69.7m2. Saturated steam at 383.2K is supplied for heating. Since the solution is dilute, it can be assumed to have the same boiling point as water. The heat capacity of the feed can be taken as cp=4.10kJ/kgK. Calculate the amounts of vapor and liquid product and the overall heat-transfer coefficient U. 8.4-7. Effect of Feed Temperature on Evaporating a NaOH Solution. A single-effect evaporator is concentrating a feed of 9072 kg/h of a 10wt. % solution of NaOH in water to a product of 50% solids. The pressure of the saturated steam used is 42kPa (gage) and the pressure in the vapor space of the evaporator is 20kPa (abs). The overall heat transfer coefficient is 1988W/m2K. Calculate the steam used, the steam economy in kg vaporized/kg steam, and the area for the following feed conditions: a. a.Feed temperature of 288.8K(15.6C) b. Feed temperature of 322.1K(48.9C) 8.4-7. Throughput of a Single-Effect Evaporator. An evaporator is concentrating Fkg/h at 311K of a 20wt. solution of NaOH to 50%. The saturated steam used for heating is 399.3K. The pressure in the vapor space of the evaporator is 13.3kPa abs. The overall coefficient is 1420W/m2K and the area is 86.4m2. Calculate the feed rate F of the evaporator