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Fractionation System

In the fractionation system at Innventia, pulp can be separated into different fractions using screens and hydrocyclones. The fractionation system is totally integrated with the stock system and the FEX paper machine and it can be operated as a continuous process together with these. It can also be operated separately for fractionation studies.

The plant is set-up in a modular sway to achieve flexibility in process configuration and capacity. It is a toolbox with equipment that can be connected and operated according to the specific demands of an assignment. For instance, most of the equipment, machinery, tanks and pumps are mobile and connected with hoses. The plant has the possibility to integrate fractionation and fibre treatment in the approach flow system of the FEX paper machine.

Four unit operations

The fractionation system consists of four unit operations; mixing, fractionation, fibre treatment and thickening.

Beskrivning: Fractioning model

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

In the fractionation section, the fibre flow is separated using hydrocyclones and/or screens, mostly into a fine fraction and a coarse fraction. The cyclones separate according to fibre morphology and bonding ability; e.g. wall thickness, flexibility and fibrillation. The screens separate according to fibre size; e.g. fibre length. The screens can also be used to separate fines from the stock as well as they can be used as filters to increase the concentration, e.g for LC-refining.

Fibre treatment can be done in the three LC-refiners. They can operate on the entire stock or just treat a coarse fraction. The three refiners can be operated as single units in different parts of the process or in series. Fillings to suit different pulps are available.

In the thickening section, dewatering equipment is used to increase the fibre concentration to a level suitable for further use or for storage, e.g. refining. The bow screen can also be used to separate fines from the stock.

High flexibility under industrially relevant conditions

Thanks to the modular set up it is possible to install and evaluate new process equipment and measurement technology of different kinds. The fibre flow in the system can be studied using for example the STFI FiberMaster or OptoPlatform. In that way properties such as fibre dimensions, fines content and crill 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 process. The guarantees that the fibres are effectively utilised, all feed fibre material will end up in the final fractions.

The fractionated pulp can be used for manufacturing both single- and multi-layered products under industrially relevant conditions.


Annika Bjärestrand
+46 768767028
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