Title:
Unravelling an Efficient Fractionation of Complex Mixed Lignocellulosic Feedstocks in a Pilot Scale Biorefinery
Author(s):
Verges, M., Schulze, P., Smit, A., van Zomeren, A., Rasche, C.
Document(s):
Paper
Abstract:
Successful future lignocellulosic biorefineries should combine both – high efficiency and flexibility. An efficient fractionation is necessary in order to obtain all major fractions - cellulose, lignin and hemicellulose - at high yields and qualities. Flexibility for different feedstocks or even mixtures of them leads to an economic advantage. Low requirements on a feedstock enables the use of un- or underutilized streams and creates independence from the individual product markets. As fractionation conditions usually have to be adjusted to each feedstock, this is a challenge. Within the H2020-BBI JU project UNRAVEL (www.unravel-bbi.eu) an innovative concept for the pre-treatment of different kinds of hardwood and agricultural feedstocks is developed and scaled up to pilot scale. A special focus lies on the processing of a mix of feedstocks for the first time on this scale. The process chain involves pre-extraction, FABIOLA™ organosolv fractionation [1] and LigniSep advanced continuous lignin precipitation with integrated solvent recovery [2]. Pre-extraction is applied to unify the feedstock properties and to increase product purity. The extract can be used for renutrition of soil or isolation of high value products like betulin from birch bark. Using acetone as a solvent, the FABIOLA™ process was designed to enable a low temperature organosolv pretreatment [1].It results in a relatively unaltered lignin fraction, high cellulose yield and high yields of monomeric hemicellulose sugars compared to ethanol pulping. Furthermore solvent recovery is efficient with low energy demand. In this concept, it is integrated in an advanced continuous lignin precipitation by solvent evaporation [2]. The pulp fraction is saccharified in an enzymatic hydrolysis and all sugar streams are concentrated to a syrup. In the project, the lignin is tested in PUR/PIR foams and bitumen applications. Product sugar solutions are fermented towards chemicals to prove their low microbial toxicity. In this work, results from the first scale up of the pre-treatment of a feedstock mix of birch woodchips with bark and branches and wheat straw are presented. The mix was chosen to prove a high flexibility of the process for very different feedstocks of high availability. The whole process chain is successfully demonstrated at TRL5 using a 460 L batch pulping reactor. Water-acetone pre-extraction was successful with a yield of 73 % of theoretical dry weight of total extractives. Subsequent fractionation leads to a pulp yield of 46 % and lignin solubilisation of 67 %. Although the LigniSep precipitation was successful, some apparent lignin losses were noted at the surfaces of the equipment and due to inefficient pulp washing. All in all the experiment showed very promising with regards to scalability. Specific items with potential for improvement have been identified. For all process steps, mass balance data is collected and used for a full sustainability assessment including LCA and techno-economics within the UNRAVEL Project.
Keywords:
biorefinery, lignin, lignocellulose, pilot plant, pretreatment, organosolv
Topic:
Biomass Conversion to Intermediate Bioenergy Carriers, Sustainable Biofuels and Bio-Based Products
Subtopic:
Biorefineries
Event:
29th European Biomass Conference and Exhibition
Session:
3CV.5.16
Pages:
951 - 953
ISBN:
978-88-89407-21-9
Paper DOI:
10.5071/29thEUBCE2021-3CV.5.16
Price:
FREE
