- How does it work?
- What can it be used for?
- What can it not be used for?
- Related Facilities
- Further Information
|Key words||dewatering, juice concentration, wine concentration, concentration, desalination, aroma rejection, flavour rejection, metal ions rejection, colourants rejection, hyperfiltration, reverse osmosis, cut-off, dealcoholization, purification, waste water treatment, membrane|
|Completed by||Wageningen UR - FBR|
How does it work?
|Working principle|| Reverse osmosis designates a membrane separation process, driven by a pressure gradient, in which the membrane separates the solvent (e.g. water, alcohol) from other components (e.g. aromas, metal ions, colours) of a solution. The selectivity of the membrane defines the separation process and depends mostly on membrane material. Commonly pore sizes are 1-10 Å (0.0001 - 0.001µm). pressures needed are 1380 – 6890 kPa (200 – 1000 psi, 15 – 70 bar). Permeate fluxes, which can be reached vary between 3 – 30 l/m2 h.|
|Additional effects|| Positive: Removal of microorganisms to a large extent
Negative: Also selective for undesired components
|Important process parameters||pressure, membrane type and material, surface properties of the membrane, surface area of the membrane, temperature, cross flow velocity|
|Important product parameters||viscosity, particle concentration, diffusivity, density|
What can it be used for?
|Products||Liquids, beverages, clarified juices|
|Operations||Desalination, dealcoholisation, dewatering, concentration, purification|
|Solutions for short comings|| - Fouling of the membrane surface
- High water and cleaning detergents consumption during cleaning procedure - Wet storage of the membrane necessary - Pretreatment necessary (Clarification by NF/MF) - High concentrations are difficult to obtain due to the high osmotic pressures (one stage RO: 20 – 35◦Brix, two stage RO up to 40-50◦Brix)
What can it NOT be used for?
|Products||Solids, gas, high viscous liquids, non-clarified liquids|
|Operations||Reverse osmosis is used for dewatering, but not for clarification (nanofiltration or microfiltration) Reverse osmosis can be used for pasteurization, but not for sterilization (NF or MF)|
|Other limitations||Permeate fluxes are relatively low (3-30 l/m2 h)|
|Risks or hazards||Careful cleaning is necessary, since reverse osmosis membranes need to be stored under wet conditions, which support the growth of microorganisms.|
|Maturity||Lab-scale, pilot-scale and industrial scale possible|
|Modularity /Implementation||Reverse osmosis can be inserted in an existing production line|
|Consumer aspects||Not available|
|Legal aspects||Not available|
|Environmental aspects||Reverse osmosis energy consumption is low when compared with evaporation.|
Facilities that might be interesting for you
|Institutes||University Twente - Membrane Technology Group, Johannes Keppler Universität Linz - Institut für Verfahrenstechnik|
|Companies||Applied Membranes INC., MMS membrane Systems|
|References|| 1. Girard, B. and Fukumoto, L.R.; Membrane Processing of Fruit and Beverages: A review, Critical Reviews in Food Science and Nutrition, Volume 40, Issue 2, p. 91-157, 2000.
2. Baker, R. W.; Membrane Technology and Applications, 2nd edition, ISBN 0-470-85445-6, 2004.
pressure, membrane type and material, surface properties of the membrane, surface area of the membrane, temperature, cross flow velocity viscosity, particle concentration, diffusivity, density Membrane equipment 2.2.1 physical separation not applicable Web of knowledge (Searchterms: Reverse Osmosis AND Food) WikiSysop :Template:Review document :Template:Review status