Fiber and film industry

Prefiltration to protect filter membranes in the caustic soda cycle

Lye filtration in viscose production

In viscose production for cellulose-based products, a significant proportion of the caustic soda used in the alkali ripening process is squeezed out by continuous or discontinuous mechanical dewatering devices.

The recovered lye is filtered and returned to the manufacturing process to ensure a sustainable circular economy.

Leakage of hazardous media and high manual intervention in conventional systems.

Filter presses and belt filters are predominantly used for the filtration of caustic soda, even though their disadvantages are well known. These systems are open in design, which is no longer appropriate for safety reasons when handling this medium.

In addition, frequent cloth changes and design-related factors result in high maintenance costs.

Completely closed system without chemical losses.

The installation of a closed and fully automatic pre-filtration system in combination with a fully automatic backwash filter ensures maximum process reliability and effectively protects downstream equipment such as membrane based filtration systems or secondary consumers.

These modern filter systems enable long maintenance intervals due to high cloth service life thanks to their efficient backwashing and increase the service life of the modules.

The solution: LENZING CakeFil in pre-filtration

Fully automatic filter system with consistent filtrate quality and a high degree of automation.

up to 5 yearsservice life filter cloth
2 m³/m²hThroughput per filter area
< 1 ppmFiltrate quality
< 1 µmFilter fineness

Process diagram for press lye filtration — Process representation of a LENZING CakeFil installation with a downstream LENZING OptiFil system

Filtration of caustic soda in viscose production

Advantages of using the LENZING CakeFil system

Cost savings

Innovative patented candle design and efficient backwashing process enable long service life and thus minimal maintenance costs.

System performance

Closed system and long filter cloth service life result in high levels of automation without chemical losses.

Securing the circular economy

Thanks to optimal pre-filtration resulting in a particle-free medium, the filtered lye can be reused for further applications in the process.

LENZING CakeFil

The LENZING CakeFil system is a process candle filter for cake building filtration with slurry or dry solids discharge. Its patented system enables highly efficient backwashing, thereby extending the service life of the filter fabric.

Filtration down to submicron range

Dry or slurry discharge

Efficient cake discharge

Unbeatable cloth service life

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