Case Study:
T-CUT PP/PVDF in Practical Use at a North German Manufacturer of Adsorber Material
The Challenge:
The end customer has been using a diafiltration plant with membrane modules from CUT Membrane Technology GmbH in its chemical production process for over ten years. The aim of the filtration process is to wash out dissolved salts from a freshly precipitated iron hydroxide suspension. The highly viscous suspension is circulated through the cross-flow membrane modules, whereby the saline permeate is continuously discharged and replenished by adding fresh water to the suspension. The microfiltration modules used were state of the art at the time.The former (discontinued) type of filters were equipped with a porous polypropylene membrane (Accurel PP V 8/2) with a pore size of 0.2 μm. This sponge like, almost symmetrical membrane had to be periodically backwashed during operation in order to maintain continuous filtration operation. Blocked pores had to be cleaned up using an external CIP, thus limiting the overall process.
The lack of availability of the membrane as well as the short service life at the end user were reasons enough for us to develop of a whole new, improved tubular membrane.
The Solution (Membrane)
Our tailor made PP/PVDF membrane is ideal for dewatering the iron hydroxide solution. It is designed in such a way that dissolved particles and salts can pass through the membrane while particulate substances remain in the concentrate without blocking the pores. This is also reflected in a stable filtration flow and long service life.
During the large scale test phase (currently the modules have been filtering for more than 2 years as of 09 2025) membrane tubes were extracted from the module several times and fed into our in-house quality control for thorough evaluation. It was found that even aggressive chemical cleaning and the abrasive effects during filtration have no negative effects on the integrity of the separation layer of the filter. In addition, the laboratory results were able to provide information about certain operating parameters and thus help to operate more effectively. In particular, the preconditioning of the product and the cleaning could be perfected due to the fruitful exchange between the end user and the manufacturer.
The Solution (System Design // Conclusion)
The customer’s filtration system includes 8 installed membrane modules with a total filter area of 41.6 m². The modules are individually operated and can be switched on/off individually. The process is operated in batches, with multi shift daily operation being carried out at peak times. The total plant achieves a peak output of approx. 28 m³/h permeate and is periodically backwashed by using compressed air and produced permeate.
– Our new PP/PVDF membrane increases the former service life by at least 150%
– Up to 6 times more permeate is produced between two CIP´s
– The amount of cleaning chemicals has been reduced by at least 60%
– Labor costs for external CIP cleaning has been significantly reduced
– The higher yields reduce the specific electricity costs (kW/m³ permeate)
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