Efficient Washing of Paper grade pulp in the kraft process

The project contributes to strengthened Swedish competitiveness through its expected research results and new fundamental knowledge for the development of an efficient pulp washing process and thus through an increased pace of innovation in the transition to a circular economy.

After pulping the wood chips, the resulting pulp fibres and cooking liquor are separated in a series of counter-current washing steps in which water and/or purified condensate from the evaporation plant is used. This separation is of utmost importance in order to obtain a sufficient pure pulp but also in order to have an efficient recovery of sodium and sulphur compounds.

In this project we consider that washing is a counter-current process, thus, there is an alkali/ionic strength profile along the washing process affecting it. Furthermore, we will investigate the washing of different fibers aimed at different types of products.

The overarching aim of this project is to improve the efficiency of the pulp washing in such a way that less water/condensate is used (thus, decreasing the dilution of the black liquor) but the purity and quality of the produced pulp are not influenced in a negative way.The project contributes to the industry’s innovation ability through the training of people who can implement process-oriented research from an industrial conversion perspective.