The field of downstream processing includes the development of processes for separation and purification of product mixtures and is naturally closely interrelated with the other areas at Fraunhofer CBP.
New tailor-made processing methods for the separation and purification are developed, scaled-up and evaluated to provide customized applications.
Downstream processing and product conditioning are a decisive factor in the efficiency of the entire process chain and at Fraunhofer CBP these are integrated directly into the process development as unit operations.
Our step-by-step approach covers the conception of suitable processes, the simulation and modeling of separation processes via ASPEN and their representation on the technical and pilot scale. At the same time the industrial practicability of the processes is already evaluated at the laboratory scale and then optimized.
These trials enable us to make product samples available to our partners and customers for technical application tests.
In parallel to the process, analytical methods are employed to evaluate the material composition of the product solutions.
In addition to the above-mentioned process units the Fraunhofer CBP also has the following equipment for product purification and conditioning:
All systems are designed in accordance with ATEX specifcations (Zone 2, high-pressure extraction Zone 1).
We use various technologies for the drying of intermediates and products. For concentrating solutions or suspensions, we can gently evaporate under vacuum at Fraunhofer CBP (300 L/batch) and subsequently dry further under vacuum (30 L/batch in the cabinet dryer or 600 L/batch in the vacuum filter dryer) as well as spray drying (7.5 kg/h) or freeze drying (24 L/batch).
We are happy to provide larger drying capacities, also under hygiene requirements for the food sector, through our partner network.
Laboratory facilities for evaporation, freeze drying and spray drying are available at Fraunhofer IGB in Stuttgart for investigating the feasibility and drying of smaller sample quantities. The nozzle variants available here for spray drying enable both the spraying of homogeneous solutions (two-substance nozzle) and the spraying of two liquids that are unmixable with each other (three-substance nozzle).
The superheated steam drying process developed at Fraunhofer IGB allows volatile substances to be separated during the drying step and condensed for further use or separate disposal.
Biobased furan derivatives, such as 2,5-furandicarboxylic acid (FDCA), are increasingly gaining in importance, in particular as biogenic building blocks for polymer applications. The Fraunhofer Center for Chemical-Biotechnological Processes CBP is conducting intensive research into the separation and purification of furan derivatives from process water of the hydrothermal conversion of raw materials containing lignocellulose, using a variety of thermal, mechanical and physico-chemical separation methods. Intensive research and development has been carried out in projects including those funded by the German Federal Ministry of Education and Research (BMBF), ”KomBiChemPro” and ”BBChem”, and the project ”SteamBio”, funded by the EU.
We use cross-flow membrane systems to separate off the dissolved and undissolved constituents. The aim is to separate polymers from monomers and to reduce the water content to optimize the purification process energetically. Cross-flow membrane filtration also plays a central role in the separation of temperature-sensitive substances, such as 5-hydroxymethylfurfural (5-HMF) and formic acid. Furfural derivatives can also be successfully separated from the process water using rectification, which we have demonstrated at the pilot scale with a throughput of 2.5 kg/h. Investigations into liquid-liquid extraction and adsorption/desorption revealed targeted separation of the carboxylic acids from furan derivatives. In this case, we were able to successfully demonstrate the essential feasibility of separating furan derivatives in process waters from hydrothermal conversion up to the 100-liter scale.
Fraunhofer Center for Chemical-Biotechnological Processes CBP