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Wine Filtration with ECLIPSE MEMBRANES™

Porous PTFE Membranes for Wine Filtration

Membrane filtration has made significant inroads into the wine industry and to a lesser extent in the brewery industry. In the wine industry, membrane filtration is used as the second to last filtration step, followed only by a cartridge filtration prior to bottling. Wine is traditionally filtered to achieve clarity of the final product, removing particles, etc. that remain from earlier processing steps that impact the clarity and the taste of the wine. Unlike other filtration operations, wine can be over-filtered. Too aggressive a filtration process results in loss of colloids and large molecules that contribute to flavor and aroma of the wine; too loose a membrane structure results in a cloudy or turbid appearance to the wine.

 

When filtered via membrane filtration, a cross flow design is employed, typically with the flow from the lumen side, through the membrane wall to the outside, with the filtrate collected on the shell side of the hollow fiber membranes. The high velocity of the wine through the lumens helps maintain a clear surface and avoids the build-up of a cake which would greatly reduce the flux through the fiber wall. Typically, the permeate is recycled back through the system flushing the solids along with it until sufficient solids are concentrated which are then discarded.

 

The most predominant material for membrane filters for wine are wet or phase inversion membranes spun from polysulfone or polyethersulfone. The ends are potted in epoxy or polyurethane systems that are prone to shrinkage, cracking, and fiber pull-out. While these fibers exhibit acceptable pore size distributions for the application, they are physically very delicate, and subject to breaking down chemically during cleaning processes and are severely limited (60°C) by temperature.

Advantages to Markel's Membrane Filtration & Custom Potting System

Markel is developing filter modules for the crossflow filtration of wine based on our porous PTFE hollow fiber and fluoropolymer potting system. The advantages to the wine industry are many and significant:

 

1. There is a radical difference in the ability of PTFE hollow fibers to stand up to cleaning systems generally employed for beer and wine when compared to Polysulfone. PTFE will not, nor will our potting systems, suffer any short or long term repercussions from the cleaning systems employed by the winery.

 

2. PTFE hollow fibers are far more durable and strong than polysulfone or equivalent. This translates to being better able to tolerate repeated temperature and pressure swings, higher pressures for filtration improving rates, higher pressures for backflushing reducing cycle times for cleaning, etc. The service temperature for both the fiber and the potting system is significantly higher (160°C or thereabouts vs. 60-80°C for polysulfone) allowing hotter temperatures during cleaning, reducing cycle time.

 

3. The use of ozone is also enabled by PTFE. Ozone cleaning processes and systems are making inroads in food and beverage, are lower cost, and have effectively no waste stream compared to conventional cleaning methods. Employment in the wine and beer markets has been limited to ancillary equipment as the incumbent membranes will not stand up to the aggressive attack from ozonated water. A PTFE membrane filter will enable these systems to be employed, representing a cost savings to the winery or brewer.

 

4. The PTFE module has a far more robust potted end, reducing the likelihood of pull out or pull-away.

 

To discuss these advantages further, contact one of our design engineers.

More Information about Porous PTFE Membranes for Wine Filtration

 

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