Biomass fractionation

The processes that can be realized in the pilot plant for fractionation of lignocellulosic biomass are shown in the simplified plant diagram. First, lignocellulose is pulped in a 400-liter reactor at up to 200°C, whereby lignin and hemicelluloses dissolve in the ethanol-water mixture. The additional tanks and heat exchangers in the tank farm permit an efficient displacement washing of the feedstock under reaction conditions as well as the energy recovery within the pulping process. From the lignin and hemicellulose rich liquor, lignin is precipitated by adding water or by distillation of the ethanol, filtered off, washed, and  dried. The used ethanol is recovered completely from the filtrate while the hemicellulose sugars remain in the aqueous solution. The solid, fibrous residue from pulping is isolated and washed, dewatered and, if necessary, enzymatically hydrolyzed to glucose in specially designed stirred reactors at high consistency. After filtration, the glucose solution is concentrated into a syrup for long term storage.

In the second phase of the “Lignocellulose Biorefinery” collaborative BMEL-funded project, the Organosolv fractionation was transferred to the pilot scale successfully, and in accordance with the biorefinery concept, it was demonstrated that the wood can be used as a feedstock for chemicals on the technical scale. The pilot plant is now being used in international and national research projects to further optimize the process, to integrate the intermediate products obtained in various value-added chains, and finally to pave the way for the industrial implementation of the technology.