QUANTIFICATION OF FLUX DECLINE AND DESIGN OF ULTRAFILTRATION SYSTEM FOR CLARIFICATION OF TENDER COCONUT WATER V.K. JAYANTI 1 , P. RAI 2 , S. DASGUPTA 1 and S. DE 1,3 1 Department of Chemical Engineering Indian Institute of Technology Kharagpur 721 302, India 2 Department of Agricultural Engineering Birsa Agricultural University Kanke, Ranchi 834006, India Accepted for Publication February 13, 2008 ABSTRACT Clarification of tender coconut water was carried out in a continuous stirred ultrafiltration cell at transmembrane pressures of 276, 414, 552 and 690 kPa and at stirrer speeds of 800 (Reynolds number [Re] = 0.93 ¥ 10 5 ), 1,000 (Re = 1.17 ¥ 10 5 ), 1,400 (Re = 1.63 ¥ 10 5 ) and 1,600 (Re = 1.87 ¥ 10 5 ) rpm, for each pressure. Permeate flux decline was analyzed using a first-order kinetic model for the development of the polarized layer resis- tance. Correlations were proposed for the steady-state polarized layer resis- tance with the operating conditions, e.g., transmembrane pressure difference, Reynolds number and membrane resistance. Decrease in membrane perme- ability after subsequent experiments was also quantified. Average irreversible fouling resistance was estimated as 7.5 ¥ 10 12 m -1 . Using the developed design equations of the stirred continuous ultrafiltration system, finally, the perfor- mance of such system in terms of productivity as function of operating condi- tions, membrane area and number of cleaning cycles was also evaluated. PRACTICAL APPLICATIONS The application of membrane technology is one of the emerging areas in the food industry. The major application includes fruit juice clarification and concentration. Because of the nonthermal nature of membrane separation, the 3 Corresponding author. TEL: 91-3222-283926; FAX: 91-3222-255303; EMAIL: sde@ che.iitkgp.ernet.in Journal of Food Process Engineering 33 (2010) 128–143. All Rights Reserved. © Copyright the Authors Journal Compilation © 2008 Wiley Periodicals, Inc. DOI: 10.1111/j.1745-4530.2008.00264.x 128