title: Performance assessment of membrane distillation for skim milk and whey processing.
abstract: Membrane distillation is an emerging membrane process based on evaporation of a volatile solvent. One of its often stated advantages is the low flux sensitivity toward concentration of the processed fluid, in contrast to reverse osmosis. In the present paper, we looked at 2 high-solids applications of the dairy industry: skim milk and whey. Performance was assessed under various hydrodynamic conditions to investigate the feasibility of fouling mitigation by changing the operating parameters and to compare performance to widespread membrane filtration processes. Whereas filtration processes are hydraulic pressure driven, membrane distillation uses vapor pressure from heat to drive separation and, therefore, operating parameters have a different bearing on the process. Experimental and calculated results identified factors influencing heat and mass transfer under various operating conditions using polytetrafluoroethylene flat-sheet membranes. Linear velocity was found to influence performance during skim milk processing but not during whey processing. Lower feed and higher permeate temperature was found to reduce fouling in the processing of both dairy solutions. Concentration of skim milk and whey by membrane distillation has potential, as it showed high rejection (>99%) of all dairy components and can operate using low electrical energy and pressures (<10 kPa). At higher cross-flow velocities (around 0.141 m/s), fluxes were comparable to those found with reverse osmosis, achieving a sustainable flux of approximately 12 kg/h·m(2) for skim milk of 20% dry matter concentration and approximately 20 kg/h·m(2) after 18 h of operation with whey at 20% dry matter concentration.
authors.affiliation: Institute for Sustainability and Innovation, College of Engineering and Science, and.
authors.forename: Angela
authors.initials: A
authors.lastname: Hausmann
authors.affiliation: Institute for Sustainability and Innovation, College of Engineering and Science, and.
authors.forename: Peter
authors.initials: P
authors.lastname: Sanciolo
authors.affiliation: Advanced Food Systems Research Unit, College of Health and Biomedicine, Victoria University, PO Box 14428, Melbourne, Victoria, 8001, Australia.
authors.forename: Todor
authors.initials: T
authors.lastname: Vasiljevic
authors.affiliation: Institute for Food Process Engineering and Dairy Technology, Technische Universität München, 85354 Munich, Germany.
authors.forename: Ulrich
authors.initials: U
authors.lastname: Kulozik
authors.affiliation: Institute for Sustainability and Innovation, College of Engineering and Science, and. Electronic address: mikel.duke@vu.edu.au.
authors.forename: Mikel
authors.initials: M
authors.lastname: Duke
mesh_terms: D000818:Animals; D002244:Carbon / Q000032:analysis; D002851:Chromatography, High Pressure Liquid; D057168:Distillation / Q000379:methods*; D005374:Filtration / Q000379:methods*; D005511:Food Handling / Q000379:methods*; D007785:Lactose / Q000032:analysis; D008566:Membranes; D008892:Milk / Q000737:chemistry*; D008894:Milk Proteins / Q000737:chemistry*; D008962:Models, Theoretical; D009584:Nitrogen / Q000032:analysis; D011312:Pressure; D013054:Spectrophotometry, Atomic; D013696:Temperature; D000067816:Whey Proteins
chemical_list: D008894:Milk Proteins; D000067816:Whey Proteins; D002244:Carbon; D007785:Lactose; D009584:Nitrogen
keywords: membrane distillation; membrane performance; milk concentration; whey concentration