EXAMPLE 8.6. Concentration of tomato juice in a climbing film evaporator
Tomato juice is to be concentrated from 12% solids to 28% solids in a climbing film evaporator, 3 m high and 4 cm diameter. The maximum allowable temperature for tomato juice is 57°C. The juice is fed to the evaporator at 57°C and at this temperature the latent heat of vaporization is 2366 kJ kg-1
Steam is used in the jacket of the evaporator at a pressure of 170 kPa (abs). If the overall heat-transfer coefficient is 6000 J m-2 s-1 °C-1, estimate the quantity of tomato juice feed per hour. Take heating surface as 3 m long x 0.04 m diameter.