The Europoly project case study saw Rhodia-Solvay and BASF collaborate to design and build a continuous, multi-product pilot plant to demonstrate the technical and economical viability of the F³ Factory concept for the production of solution polymers.
Water soluble synthetic polymers are used in a wide range of markets and applications with production of water soluble polymers in Europe estimated to be greater than 750 000 tonnes per annum with a market value of over €2.5 billion.
The project was supported by academic partners, CNRS Nancy and TU Dortmund, where feasibility studies were undertaken on two model polymer systems:
- acrylic acid-based copolymer (CNRS & Rhodia-Solvay)
- homo-polymerisation of acrylic acid and copolymerisation of acrylic acid with a second monomer with extremely different copolymerisation parameters (TU Dortmund and BASF)
A key challenge in polymer production is to manage the high heat production rate during radical polymerisation reactions. This is particularly difficult to manage in conventional large-volume stirred batch reactors due to heat transfer limitations related to the low surface area-to-volume ratio of the reactor vessel. These batch processes are usually run in fed-batch mode with a long cycle time and semi-continuous addition of reactants, such as monomers and initiators, to control the extent of the exothermic reaction.
The Europoly project evaluated the advantages of a new continuous, intensified process technology that could deliver the required product characteristics with a heat transfer capability more appropriate for the reaction.
In other words the project looked to adapt the process to the product rather than the traditional approach of adapting the product to the process!
In transferring production from batch to continuous mode, based on process intensification and standardised modules, the project team targeted improved sustainability and competitiveness objectives through:
- increased productivity for the same investment cost
- reduced fixed costs through lean processes and productivity enhancements
- improved process robustness by replacing batch reactors used to manufacture multiple products with continuous, product-optimised processes
- improved product uniformity resulting from continuous process control in place of batch production (i.e. to eliminate batch-to-batch deviations in product quality)
A key success of the project was the development of a scalable mixer-heat exchange tubular reactor concept using Fluitec static mixer technology. This reactor is equipped with a novel internal cooling system element that controls heat production during the process.
Intensive use of kinetic data in millifluidic devices and rheokinetic data from lab-scale batch reactors, that were tested during the validation stage, was key to the successful design of the intensified continuous reactor used in the demonstration stage. The continuous polymerisation process was monitored by:
- in-line spectroscopy with mid-infrared at TU Dortmund
- Raman spectroscopy at CNRS, Nancy
Lab-scale evaluation at TU Dortmund and CNRS, Nancy successfully validated the transfer of (co)polymerisation reactions from batch to continuous operation for both products. Process intensification factors from 10 to 100 were achieved with products in specification in relation to:
- residual monomer content
- molecular weight
The successful transfer of the copolymerisation reactions to continuous flow was achieved.
The new process was designed to fit in a half-sized standard process equipment container (PEC) that was initially fabricated at Rhodia-Solvay’s site in France. The completed PEC was transported to (see above) and installed at the INVITE Research Centre in Leverkusen, Germany during quarter two of 2013 and the process was successfully demonstrated.
The Europoly case study highlighted the overall F³ Factory concept of ‘fast, flexible and future’ by achieving:
- Fast: The continuous operation of an intensified process.
- Flexible: The use of the same PEC and PEAs (process equipment assemblies) for two different polymers.
- Future: By using modular technology in a multi-product environment i.e. use of the same PEC and PEAs.