Fraunhofer Center for Chemical-Biotechnological Processes CBP
Fraunhofer Center for Chemical-Biotechnological Processes CBP

Downstream Processing

Innovative methods for efficient downstream processing

Challenge: Methods for the efficient separation and purification of valuable substances

Chemical syntheses and biotechnological manufacturing processes typically result in mixtures of substances or products that are contaminated with byproducts or that must be separated from the fermentation broth and purified. A key task in most chemical and biotechnology processes is therefore the separation of molecules from mixtures, either to recover or purify substances or to remove undesirable byproducts. The processes used for product processing and conditioning significantly determine the efficiency of the entire process chain for the production of chemical and biotechnology products.

Our unique selling proposition: Processing methods from the laboratory to the pilot scale

At the Fraunhofer Center for Chemical-Biotechnological Processes CBP, we offer comprehensive solutions for downstream processing and product purification in biotechnological and chemical processes. Our range of services includes the development, scaling, and evaluation of processing methods for product mixtures from the laboratory scale up to the pilot scale.

We utilize state-of-the-art technologies to develop customized solutions tailored to your needs. For example, we are able to extract high-quality products such as furan derivatives or carboxylic acids from by-products and side streams of the renewable raw materials processing industry, process fermentation solutions, or purify organic components—such as phenols—from chemical process streams.

Range of services

The efficiency of a process for manufacturing basic and fine chemicals is significantly influenced by product recovery, which is why this step should be closely integrated into the process development of the manufacturing process.

Our step-by-step approach to designing a recovery process includes the conception and selection of suitable separation methods, modeling using simulation techniques, and experimental replication and investigation at both the laboratory and pilot scales.

In this process, the industrial feasibility of the recovery methods is evaluated at the laboratory scale and then optimized. The data generated is used for techno-economic analyses and serves as the basis for further scaling of the processes up to the industrial scale.

Through experimental investigations, we provide partners and customers with initial product samples for application-specific characterization. 

Scaling and optimization of downstream processing

Our expertise covers a wide range of processing methods that are precisely tailored to your product requirements. By scaling your processes to the pilot scale, we help you optimize your production processes both economically and technically.

Simulation for cost and process optimization

Time and costs are critical factors in process development. We therefore use simulation software to determine optimum process parameters in advance. Simulation allows us to identify the best conditions for distillation, extraction, etc. without the need for costly and time-consuming experiments.

Benefits overview:

  • Time and cost savings: Reduction of experimental effort through pre-simulation
  • Further cost reduction: savings on raw and additional materials
  • Increased efficiency: Optimum definition of process parameters that lead to higher product quality and yield
  • Safety factor: Critical process steps can be identified and eliminated in advance

The implementation of process simulation is a key step in modern industrial research and development.

Features

Equipment for product purification and conditioning

The following equipment is available at Fraunhofer CBP for product processing:

  • Distillation columns for processing at atmospheric pressure and under vacuum, with capacities ranging from 1 L/h to 80 L/h
  • Fall-film, thin-film, and short-path evaporators for vacuum distillation up to 350 °C, designed in accordance with ATEX guidelines and with throughput rates of up to 60 L/h
  • Liquid-liquid extraction system with a maximum throughput of 85 kg/h
  • Solid-liquid extraction unit with a capacity of 25 L
  • High-pressure extraction system for continuous and batch operation using liquid propane and supercritical carbon dioxide, with extraction rates up to 10 kg/h

All systems are designed in accordance with ATEX (Zone 2; high-pressure extraction: Zone 1).

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Thermal purification

Using process techniques such as drying, distillation, rectification, etc., mixtures can be separated based on their different vapor pressures.

A key feature of the Fraunhofer CBP is its ability to perform these processes in an explosion-proof environment. It is also possible to gently separate temperature-sensitive or high-boiling-point products under vacuum.

Equipment and services drying technologies

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.

Falling film evaporator
Falling film evaporator.
Vacuum rectification
Vacuum rectification.
High temperature vacuum distillation plant
© Norbert Michalke / Fraunhofer CBP
High temperature vacuum distillation plant.

Further information on the Fraunhofer IGB website

Physical-chemical purification

Our core competencies include solvent-based extractions such as solid-liquid extraction and liquid-liquid extraction, as well as pressure-driven non-solvent-based separation techniques such as membrane filtration including nanofiltration and reverse osmosis. We also offer our partners product treatment by adsorption and absorption.

Mechanical purification

The mechanical processing of mixtures such as suspensions and emulsions requires methods for separating solids from liquids through filtration and centrifugation. Vacuum drum filters and filter presses separate solid particles from liquids, while disc separators use centrifugal forces for density separation.

With our expertise in this field, we can support you in developing and further optimizing your process.

Best-practice applications and references

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Separation and purification of furan derivatives from coupling streams containing lignocellulose

Two-phase mixture of water and furfural
© Fraunhofer CBP
Two-phase mixture of water and furfural (right), obtained by depolymerization of lignocellulose and separation by distillation.

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.

 

Separation by cross-flow membrane filtration

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.

Tubular ceramic membrane
© Fraunhofer CBP
Tubular ceramic membrane in the cross-flow membrane system.
Flat-sheet membrane module
© Fraunhofer CBP
Flat-sheet membrane module in the cross-flow membrane system.
Product sample
© Fraunhofer CBP
Product samples purified from process water using a polymer membrane, from left to right: educt sample, permeate, concentrate.

Reference projects

Examples of successful downstream tasks

  • Production of high-quality extractives from secondary and side streams of the renewable raw materials processing process industry by liquid-liquid extraction with organic solvents or at high pressures with liquid propane and supercritical carbon dioxide
  • Downstream processing of fermentation solutions and extraction of fine chemicals
  • Extraction of organic components from process streams through extraction / distillation, filtration
  • Separation and purification of furan derivatives from lignocellulosic coupling streams
  • Extraction of high-quality substances from algal biomass
 

Research infrastructure

 

© Norbert Michalke

Chemical and combined processes

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