Black Liquor Valorisation: Unlocking Lignin for the Circular Bioeconomy
What is Black Liquor in the Pulp and Paper Industry?
Black liquor is a major industrial side stream generated by the pulp and paper industry during the kraft pulping process. It contains a complex mixture of lignin, hemicellulose residues, and inorganic chemicals used to process wood.
Traditionally, black liquor is concentrated and burned to produce energy and recover chemicals. While this process is efficient, it limits the potential of lignin valorisation to energy recovery instead of higher-value applications.
Why Black Liquor is a Key Resource for Lignin Valorisation ?
Lignin is one of the most abundant natural polymers and a promising alternative to fossil-based aromatic compounds used in chemicals and materials.
However, conventional lignin valorisation often requires costly extraction and purification steps. As a result, most lignin in black liquor is still underutilised, despite its potential to contribute to the circular bioeconomy.
The SPLENDOR Project: A New Approach to Black Liquor Valorisation
The SPLENDOR project explores innovative pathways for black liquor valorisation by working directly from this industrial side stream, without relying on purified lignin.
Using advanced lignin depolymerisation and separation processes, the project aims to break down lignin into smaller molecular building blocks and isolate valuable bio-aromatic fractions.
These fractions can be used in several industrial applications, including:
- bio-based chemicals
- coatings
- rubber and tyre additives
- sustainable fuel components
At the same time, the process supports the recovery and reuse of inorganic chemicals within the pulp mill, enhancing circularity.
From Research to Industrial Application
A central objective of the SPLENDOR project is to move beyond laboratory research and demonstrate black liquor valorisation at pilot scale.
The project includes the development of a 250 L/h prototype, designed to operate under industrially relevant conditions. This step is essential to assess system performance, feedstock variability, and continuous operation.
In parallel, modelling and experimental work support process optimisation and contribute to the design of future large-scale systems.
Black Liquor and the Circular Bioeconomy
Transforming black liquor into valuable products supports the transition towards a circular bioeconomy by reducing reliance on fossil-based resources and improving resource efficiency.
By unlocking the potential of lignin, industries can develop new bio-based value chains while integrating sustainable practices into existing infrastructures.
Black liquor valorisation represents a promising opportunity to turn an abundant industrial side stream into a valuable resource. Through its integrated approach, the SPLENDOR project contributes to advancing lignin valorisation and supporting the development of sustainable and circular industrial systems.
