Theoretical and experimental study on membrane distillation in the concentration of orange juice

Membrane distillation is a relatively new membrane process in which two solutions at different temperatures are separated by a microporous hydrophobic membrane. This process can be used to concentrate fruit juices. The transport phenomena involved in membrane distillation for the concentration of fruit juices are described. Heat and mass transfer balances have been formulated, accounting for the geometry and morphology of the membrane and the properties of juice solutions. An experimental study of the concentration of orange juice with a hydrophobic poly(viny1idene fluoride) flat membrane is also presented in this paper. The experiments mainly inspect the transient phenomena, the flux decay with respect to concentration increase, the effects of operating conditions on the permeate flux, and the membrane retention of orange juice compositions. The results show that membrane distillation is a potential and feasible concentration technique.