3. A Swenson-Walker crystallizer has to produce 800 kg per hour of FeSO4-7H2O crystals. The saturated solution enters the crystallizer at 49°C and the slurry leaves at 27°C. Cooling water enters the crystallizer jacket at 15°C and leaves at 21°C. The overall heat transfer co-efficient has been estimated to be 175 kcal/(hr)(m²)(°C). There are 1.3 m² of cooling surface per metre of crystallizer length. (i) Estimate the cooling water requirement in kg/h. (ii) Determine the number of crystallizer sections, each section being 3 metre long. Data: Saturated solutions of FeSO4 at 49°C and 27°C contain 140 parts and 74 parts of FeSO4 7H₂O per 100 parts of free water respectively. Average specific heat of the initial solution is 0.70 and the heat of crystallization is 15.8 kcal/kg. Activate