The work in FRACTION has been structured in 4 main lines that are hierarchically organised:
1. Optimisation of the fractionation process of the biomass.
2. Development of downstream processes of the three lignocellulose fractions and production of intermediate building blocks.
3. Formulation and validation of end products based on these building blocks.
4. Maximisation of project impacts.
For the fractionation process, we have demonstrated that moisture and particle size have no effect on the yields and purity of the streams, so we can use wet wood chips as feedstock. We can also work with mixtures of feedstock with no negative effect. Overall, we have fulfilled the objective of demonstrating that we can extract >90% of the hemicellulose and >90% of the lignin, while >90% of the cellulose remains as solid with >90%. We have reached lignin extraction and cellulose purity of close to 80%. In addition, we have scaled-up the process to a 20 L reactor, producing samples of cellulose, hemicellulose and lignin at kg scale.
The downstream processes have tested lignin and hemicellulose from biomass fractionation. For cellulose, we have demonstrated that it can be bleached following conventional methods, has not been degraded, and is a potential feedstock for dissolving pulp application. Hemicellulose has been converted to furfural with >75% yield for samples rich in C5 sugars. Samples rich in C6 sugars have been processed to purify the sugars, and used to produce alkyl lactates and frutosides. The lignin has been oxidized, converted to products such as vanillin, and hydrogenated to polyols.
The lignin produced in FRACTION has been tested in the production of polyurethanes and resins, where we have demonstrated that up to 20% of phenols can be replaced by lignin. Also, PBS (polybutylensuccinate) and other polyols have been obtained from succinic acid and 1,5 pentanodiol produced in the project.
To make the FRACTION concept attractive for bioindustries, we have studied its sustainability and economic viability. The technoeconomic analysis has demonstrated that cellulose can be produced at 865 €/MT, lignin at 326 €/MT and furfural at 1535 €/MT, all competitive with current market prices. Other products, such as lignin polyols and carbonate, also show potential for commercialization. Furthermore, we have identified bottlenecks and proposed optimisations that reduce the energy requirements by almost 90%, compared to the initial study. The sustainability and LCA analysis has shown that GHG emissions were reduced by more than 50%, compared to preliminary estimations. We have determined the environmental impact of intermediates and main end products. The environmental foot-print of the end-products shows improvement compared with fossil-based reference products. In particular, lignin shows a reduction of 35 % with regard to phenol. Polyols based on succinic acid show a reduction in environmental impacts with regard to conventional non-SAc polyols (up to 50 %).
We have established a dialogue with key players from the European bioeconomy through activities such as the organisation of 6 Roundtables in different European countries, and presentation of FRACTION results at the 2023 CBE Stakeholder Forum, apart from participation in numerous scientific conferences. One patent based on FRACTION results has been filed and another is in preparation. Fraction result have also contributed to another, more general patent, and several other results are kept as confidential know-how with a high potential of future exploitation.
