THERMAL-CHEMICAL FRACTIONATION OF LIGNOCELLULOSIC BIOMASS

Biomass is a valuable, sustainable feedstock for the production of chemicals and materials, and will play an important role in the transition towards a Sustainable Process Industry. Bio-based products – products wholly or partly derived from materials of biological origin – can make the society more sustainable and lower its dependence on fossil fuels.  For the optimal utilization of bio-resources, fractionation on the basis of functionalities is often desired. Most commonly, biomass is separated into its main constituents lignin, cellulose and hemi-cellulose by steam or acid treatment.  Thermochemical fractionation is an alternative, innovative two-step conversion process to transform different bio-resources into rawmaterials for renewable chemicals and products. In this approach, a short thermal treatment at elevated temperature (fast pyrolysis) is followed by a low temperature fractionation of the mineral free, liquid product (FPBO) that keeps the key chemical functionalities intact in separate, liquid, depolymerized fractions. These fractions consist of components derived from the de-polymerization of cellulose, hemicellulose and lignin.  Both the fractionation of FPBO and the use of the fractions in bio-based products are further developed in the EU-funded project called Bio4Products and Interreg project “Groen Goud”. The application of the pyrolytic fractions will be demonstrated in a number of end products such as phenolic resins, sand foundry moulding resins, paints, engineered wood and natural fibre reinforced products.  Exploratory research on both the fractionation and the applications has been carried out at bench-scale using pyrolysis oil derived from different types of biomass. Results were very positive and larger quantities of pyrolytic fractions are required for further product development and demonstration. Recently, a dedicated fractionation unit with a throughput capacity of 3 ton FPBO/day has been designed, constructed and commissioned.