Mann+Hummel develops PES hollow fibre membranes

PES has a higher chemical stability, improved stability with regard to mechanical loads and permits higher operating temperatures than PAN (polyacrylonitrile), Mann+Hummel says.

The walls of the PES hollow fibres are partially permeable and function as a membrane with microfiltration and ultrafiltration. This enables a mechanical separation process. Microscopic contaminants flow through the water into the pores of the PES fibres. PES membranes for microfiltration offer pore sizes of 100-200 nm, while the membranes for ultrafiltration have pores of 10-20 nm.

Mann+Hummel plans to use the PES hollow fibres for new application areas within its water business, such as the food and beverage industry and in the field of biotechnology. In these fields, fouling (deposition) due to the filtered substances is common. The cross-flow flow guidance of the PES hollow fibre acts against this by generating a cross-flow along the membrane with high speed and automatically carrying the fouling products with it.

A bundle of hollow fibre membranes are integrated in a filter module which in turn is a component part of a newly developed modular skid design. The system consists of up to 50 filter modules and depending on the membrane type runs in cross-flow mode or dead-end mode. With dead-end filtration the fluid is pumped at low pressure against the membrane and the depositions removed at regular intervals by rinsing.

The new PES membranes are now available in Mann+Hummel’s Klar-series. The Klar-series is suitable for the treatment of process and service water for small rural communities, towns and villages, hotels and resorts and also for the treatment and recycling of industrial process and waste water. It removes foreign particles and bacteria with a turbidity of less than 0.1 NTU.

At the company's plant in Singapore, four new production lines for hollow fibre membranes are being set up and an extension of the production lines is already planned.