Scaling up of osmotic distillation from laboratory to pilot plant for concentration of fruit juices

A step-by-step procedure for scaling up of an osmotic distillation system from laboratory to pilot plant is discussed. The newly built pilot scale OD system featured a flexibility of using 1 or 2 hollow fibre modules at a time to suit the concentration demands. Three types of hollow fibres were tested on the new system. Pilot trials for OD concentration of apple, grape juices and freeze concentrated (FC) grape juice were successfully carried out to achieve a final concentration up to 65 Brix with fluxes ranging from 2.4 to 0.69kg.m-2.h-1 depending on the fibre types and the operating conditions. Cascade effect was also employed to deal with high viscosity to achieve high concentration. The obtained pilot OD fluxes were comparable to the ones obtained in the lab under similar conditions, and they fitted well with the developed models. Sensory evaluation indicated that OD well preserved the quality attributes of the fruit juices.