(b) A double effect evaporator is to be used to concentrate a 10.0 wt % organic solution to 30.0 wt %. Steam is available at 3.0 bar absolute and the pressure in the evaporation space in the final effect is 0.60 bar absolute. The overall heat transfer coefficients are 1.8 and 2.0 kW m?² K?¹ in the first and second effect, respectively. Feed solution entering the first effect at 50 °C and flow rate of 0.5 kg s?¹. The specific heat capacites of the liquid solution at feed, first effect, and second effect are 3.0, 3.5, and 3.8 kJ kg?¹ K?¹, respectively. Assume that there is no appreciable boiling point rise and the heat transfer rates are equal in both effects. Determine: (i) The evaporating temperature in the first effect. [4 MARKS] (ii) Composition of liquid leaving the first effect. [6 MARKS] (iii) The flowrate of steam required. [3 MARKS] (iv) Heat transfer surface area in the first effect. [4 MARKS]
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