6. (a) Estimate the 12°C cooling water requirement for a jet condenser to condense the 70°C vapours from an evaporator which concentrates 4000 kg h-1 of milk from 9% solids to 30% solids in one effect. If the cooling water leaves at a maximumm of 25°C. (b) For the same evaporator estimate for a surface condenser, the quantity of 12°C cooling water needed and the necessary heat-transfer area if the cooling water leaves at a maximum of 25°C and the overall heat-transfer coefficient is 2200 J m-2 s-1 °C-1 in the condenser.
[ 130 x 103 kgh-1 Note in practice this is higher ; (b) 130 x 103 kgh-1, 17.3 m2 ]