Biomass fractionation

The focus of the lignocellulose biorefinery is the pulping of lignocellulosic raw materials and the fractionation of biomass into its basic chemical components lignin and sugars or fibers. An integrated pilot plant is available for the investigation and development of fractionation and downstream processing technologies, e.g. for the pulping using organic solvents under pressure and temperature, the so-called Organosolv technique.

Integrated pilot plant

With the facility, a large number of individual process steps can be realized for the production of pulp, concentrated sugar solutions and lignin. Up to 70 kg of wood can be processed every day. The facility was designed in such a way that the material and energy cycles are closed and therefore mass balances can be determined.

Universal design

In addition to the Organosolv process, the universal design of the pilot plant also allows other pulping methods of lignocellulose to be optimized on the pilot scale, for example, aqueous hydrolysis, pulping using acid or the soda process. Comprehensive analytics are available for balancing the processes. Questions in the area of thermal separation technology and extraction can also be answered using individual process units in the plant or by cooperation with the department “Downstream Processing”.

Pilot plant process control

The core processes that can be represented in the pilot plant 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 solvent-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 solvent, filtered off and, after washing, dried. The solvent used is recovered completely from the filtrate and the hemicellulose sugars remain as an aqueous solution.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.

The oilseeds biorefinery at Fraunhofer CBP aims at the development and optimization of alternative methods for the processing of oilseeds. New processes will enable the holistic utilization of raw materials and provide higher quality product fractions compared to conventional industrial processing. In addition to the production of high-quality vegetable oils, the processing of protein-rich fractions in particular contributes to increasing the value chain. In addition, alternative extraction processes are used to extract other valuable plant ingredients from oilseeds.

At Fraunhofer CBP, new processes for processing oilseeds are being transferred from laboratory to pilot scale. Various facilities are available at the site for this purpose. From 2020, the pilot plants for peeling and ethanol extraction of rapeseed will be put into operation. A rapeseed biorefinery will be used to demonstrate a new process from seed peeling and subsequent disruption to the processing of valuable vegetable product fractions.
The flexible design of the pilot plants makes it possible to test and optimise various methods for processing oilseeds. The focus is on the future integration of alternative oilseed processing lines into the existing infrastructure of existing oil mills. The development of novel processes will not only lead to new products but also to the potential for worldwide marketing of innovative processes and plants.