The core processes that can be represented in the pilot plant for fractionation of lignocellulose 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 dissolved in the ethanol-water mixture. The additional tanks and heat exchangers in the tank farm permit an efficient fractional washing of the feedstock under reaction conditions and the recovery of energy in the pulping process. From the fractionation solution enriched with lignin and hemicelluloses, lignin is precipitated by adding water or distillation of the ethanol, filtered off and, after washing, dried. The ethanol used is recovered completely from the filtrate and the hemicellulose sugars remain as an aqueous solution. The solid, fibrous residue of the fractionation is isolated and washed, dewatered and, if necessary, enzymes are added and saccharified in specially designed stirred reactors at a high fiber concentration. After a filtration stage a glucose solution is obtained which is concentrated into a syrup to stabilize it.
With the successful transfer of the Organosolv fractionation to the pilot scale in the second phase of the “Lignocellulose Biorefnery” collaborative BMEL-funded project, it was demonstrated that the chemical use of wood in accordance with the biorefinery concept works 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 creation chains and finally to pave the way for the industrial implementation of the technology.