In the fractionation system at Innventia, pulp can be separated into different fractions using screens and hydrocyclones. The system can work separately for fractionation studies or as a part of the stock preparation system for the FEX pilot paper machine.

 

The fractionation system consists of three different sections; mixing, fractionation and thickening.

The mixing chests are needed to obtain the right inlet consistency for screens and hydrocyclones and to make it easy to change the system design.

 

In the fractionation section, the fibre flow is separated using screens and/or hydrocyclones, mostly into a fine fraction and a coarse fraction. The screens separate according to fibre size and the cyclones according to specific area and fibre density. The screen can be equipped with different screen baskets and etc the performance of the hydrocyclones can be changed by varying the design and nozzle diameters.

 

In the thickening section, dewatering equipment is used to increase the fibre concentration to a level suitable for storage and further use. For example separate refining or foming on the research paper machine.

 

The fractionation system at Innventia is designed for high flexibility and for high monitoring and control performance. The mixing chests, the fractionation equipment and the dewatering equipment may be connected to each other at will. For example, it is possible to run a two-stage fractionation hydrocyclone system working in cascade. New process equipment and measurement technology of different kinds can be installed and evaluated. The fibre flow in the system can be studied using for example the STFI FiberMaster. In that way properties such as fibre dimensions and fines content can be evaluated.

 

The fractionation system is totally closed, which means that the filtrates from the disc filter and bow screen are fed back to the mixing chests. The guarantees that the fibres are effectively utilised, all feed fibre material will end up in the final fractions. The capacity of the fractionation system is 5-15 kg/min. The result in material after one days fractionation corresponds to a one-day trial on the FEX pilot paper machine. The fractionated pulp can be used for manufacturing both single- and multi-layered products under industrially relevant conditions.