More efficiency with ceramic membranes
for liquid filtration

Cross-flow filtration is a filtration process where a suspension is pumped through porous tubes, so-called membranes, and the liquid which is filtered out, the permeate, is drawn out transversely to the direction of flow. Unlike cake filtration, the formation of a filter cake is prevented here.

For cross-flow filtration, CeramTec has specific multi-channel tubes made from aluminum oxide (Al₂O₃) on offer as carrier tubes where the application-related separation layer made up of aluminum oxide, titanium oxide or zirconium oxide is applied by the customer. The tubes are designed as ceramic membranes for mechanical separation processes: nano, ultra and microfiltration. These filtration processes are used, for example, in the food sector, pharmacy, chemical industry as well as in electroplating, environmental and biological technology.

Ceramic membrane carriers are available in various geometries for filtration. As well as different lengths, the number of channels and their diameter plays a crucial role in determining the efficiency of the filter performance. Longer carrier tubes have a greater surface area for filtration. Porous ceramic membrane tubes from CeramTec are therefore available up to a length of 1.5 meters.

“The longer the tubes are, the less tubing and periphery is required to achieve the same filter performance. The same applies for the number of channels: the more channels, the greater the filter surface and the more efficient the filter system.”

Stephanie Neuberger, Account Manager

The typical tube systems are between 1 meter and 1.5 meters, typical external diameters range from 10 millimeters to 52 millimeters and typical channel diameters are between 2 millimeters and 16 millimeters.

To go beyond the limits of the current possibilities in liquid filtration for customers, CeramTec is constantly developing the geometry and materials according to the market requirements. The current goal is to further increase the number of channels.

Membranes made from technical ceramic have the following advantages when compared with polymer membranes or sintered metal. These advantages make them especially suitable for filtration processes under pressure or at high temperatures:

• Better mechanical stability
• High thermal resistance
• High resistance against aggressive media such as acids or alkalis
• They are highly inert
• They have a high permeate flow rate
• They can be backflushed easily to remove deposits on the surface

Further properties of the CeramTec Al₂O₃ material

• Average pore channel diameter of approx. 8 micrometers
• 28 percent porosity