Conversion of dewatering to extraction of bark.

Purpose and goal

The aim of the project is to determine whether it is possible to extract tannins from bark from Swedish trees in a continuous process with the help of a bark press. Bark presses are used today only to squeeze out as much water as possible from the bark before it is burne; extraction of tannins takes place mainly from indigenous tree species in subtropical countries using discrete methods. Our hypothesis is that bark presses can be used to extract tannins from bark in a continuous process. The aim is to test this on a pilot scale during the project.

Expected effects and result

When the project is over, this will have been tested on a pilot scale and, based on the outcome, a decision can be made to proceed with the implementation of a larger R&D project and, in the long run, develop a product. The FUI project will create a completely new product from Swedish forests by adapting the equipment that already exists at the pulp / paper mills. It will also provide better raw material utilization as the tannins are extracted from the bark that is otherwise only burnt.

Planned approach and implementation

The larger bark press manufacturers provide pilot-scale equipment, which will be set up at SCA Obbola and / or at SLU´s testing facility. The trials will be done in collaboration with researchers from SLU in order to optimize the process. SCA contributes all raw material (bark) during the project period and any analyzes in their laboratory. A chip / grinding machine available at SLU will be used to grind the bark. Chemical analysis of the press-water and compilation of the result will be done by researchers at SLU.