Reverse osmosis concentration of orange juice : membrane modeling and performance

Typescript (photocopy).Membrane concentration was modeled using similitude and dimensional analysis. Pertinent variables selected by this methodology were used to determine a series of dimensionless products to describe and model mass transport through the membrane. The general model generated contained the contribution of the hydraulic configuration of the system, the fluid's behavior during concentration and the process control variables. The pseudo-Euler and the rheological numbers were able to explain the variation of permeate flux during concentration (R 2 over 0.93). The rheological, Schmidt and pseudo-Euler numbers explained the flux variation due to fluid changes during concentration and to different processing conditions (R² over 0.92). The model's sensitivity analysis showed that solids accumulation rate and viscosity significantly affected permeation rate. Orange juice was concentrated by reverse osmosis up to 50% hydraulic recovery with a polyamide membrane. Permeate fluxes and solute recoveries were determined at transmembrane pressures of 6.21 and 4.14 MPa, and at temperatures of 15 and 25 °C. Pectinase treatment was required to prevent fouling and to allow Cleaning in Place procedures. Enzymatic treatment did not affect permeate flux or solute recoveries. Solute recovery profiles for flavoring components were developed by studying concentrate and permeate composition. Overall recoveries of sugars, organic acids, and flavor-volatile components were approximately 93, 85, and 89%, respectively. Reverse osmosis can efficiently remove at least 63% of the water that needs to be removed to obtain a 42-45 °Brix concentrate