Membrane Processing
Membrane Processing
MEMBRANEFILTRATION
A membrane or, more properly, a semipermeable membrane, is a thin layer of material capable of separating substances when a driving force is applied across the membrane. Membrane filtration enables to separate particles with a diameter smaller than the pore diameter in the membrane from the liquid feed, by applying a driving force (pressure) over the membrane.
The membrane technology consists principally of Microfiltration (MF), Ultrafiltration (UF), Nano filtration (NF) and Reverse Osmosis (RO).MF is essentially employed as a clarifying operation to remove macro-materials and suspended solids, milk fat globules, bacteria and colloidal particles. The pore sizes range from0.1 to 10micron and the operating pressures are in the range of 1 to 25 psi g. UF membrane allows the particles from 10,000 to 75,000 Daltons. The operating pressure ranges between 10 to200 psi g. RO membranes are characterized by a molecular weight cut off of nearly 100 Daltons. Only water passes through while everything else including ions, organic molecules remain in the concentrate.
The pressures involved are 5-10 times higher than those used in UF. NF allows divalent ions to pass through while retaining the organic molecules. It separates particles with molecular weights in the range of 300-1000Daltons.The operating pressures required are nearly 300-psi g.
Advantages of Membrane Processes
1. Operation at ambient temperature, thus, thermal and oxidative degradation problems, common to evaporation processes can be avoided or minimized in RO/UF process. Thus, the nutritional and functional properties of milk constituents like vitamins; proteins, etc are least affected.
2. No need of any complicated heat transfer or heat generating equipment, for the membrane operation, which required only electrical energy to drive the pump motor, can be situated far from the prime power generating plant. Also no additional steam capacity needs
MEMBRANEFILTRATION
A membrane or, more properly, a semipermeable membrane, is a thin layer of material capable of separating substances when a driving force is applied across the membrane. Membrane filtration enables to separate particles with a diameter smaller than the pore diameter in the membrane from the liquid feed, by applying a driving force (pressure) over the membrane.
The membrane technology consists principally of Microfiltration (MF), Ultrafiltration (UF), Nano filtration (NF) and Reverse Osmosis (RO).MF is essentially employed as a clarifying operation to remove macro-materials and suspended solids, milk fat globules, bacteria and colloidal particles. The pore sizes range from0.1 to 10micron and the operating pressures are in the range of 1 to 25 psi g. UF membrane allows the particles from 10,000 to 75,000 Daltons. The operating pressure ranges between 10 to200 psi g. RO membranes are characterized by a molecular weight cut off of nearly 100 Daltons. Only water passes through while everything else including ions, organic molecules remain in the concentrate.
The pressures involved are 5-10 times higher than those used in UF. NF allows divalent ions to pass through while retaining the organic molecules. It separates particles with molecular weights in the range of 300-1000Daltons.The operating pressures required are nearly 300-psi g.
Advantages of Membrane Processes
1. Operation at ambient temperature, thus, thermal and oxidative degradation problems, common to evaporation processes can be avoided or minimized in RO/UF process. Thus, the nutritional and functional properties of milk constituents like vitamins; proteins, etc are least affected.
2. No need of any complicated heat transfer or heat generating equipment, for the membrane operation, which required only electrical energy to drive the pump motor, can be situated far from the prime power generating plant. Also no additional steam capacity needs