Freeze concentration is used to produce a fruit - juice concentrate. A stream of fresh juice containing 12 wt% soluble solids in water at 20C

Freeze concentration is used to produce a fruit - juice concentrate. A stream of fresh juice containing 12 wt% soluble solids in water at 20ºC is combined with a recycle stream to form a pre-concentrate, which is fed to a crystallizer. The mixture is cooled in the crystallizer to –7ºC; thereby crystallizing ice at a rate of 20,000 kg/h.

Slurry leaves the crystallizer containing 10 wt% ices and is fed to a filter. The filtrate, which contains 45 wt% dissolved solids, is removed as the concentrate product. The remaining slurry, which contains all the ice and some concentrate (also containing 45% dissolved solids), is sent to a separator that cleanly removes all of the ice

The residual liquid is the recycle stream that combines with the fresh feed to form the pre-concentrate.

Requirements:

(a) Determine the rates (kg/h) at which fresh fruit juice is fed and concentrate is produced, and the mass flow rate (kg/h) and solids concentration of the pre-concentrate.

(b) Calculate the cooling requirement (kW) for the freezer, assuming that the temperature of the recycle stream if 0ºC and the heat capacity of all solutions is 4.0 kJ/ (kg·ºC)