Bram De Jaegher
Prof. dr. ir. Ingmar Nopens - Ghent University
Prof. dr. ir. Arne Verliefde - Ghent University
Wim De Schepper - VITO
Resource scarcity of petroleum products is driving the industry towards a bio-based economy. The feed streams for bio-chemicals, produced through fermentation of natural feedstocks are complex and viscous mixtures and often require a detoxification step to improve the growth conditions in the fermenter. This detoxification step could be performed by electrodialysis, a separation technology that is able to perform selective extractions of charged molecules with a high efficiency. The application of electrodialysis to these streams is heavily hampered by fouling from these bio-based streams. An improved stack design and optimisation of the operational parameters should increase the fouling resistance of these systems and mathematical modelling can accelerate this innovation process. A mechanistic model that includes fouling mechanisms can aid in understanding the fouling behaviour and can be used as a predictive tool for the innovation of stack design and antifouling procedures.
• Gain a deeper insight into the fouling mechanisms occurring in the electrodialysis process with a main focus on organic fouling, colloidal fouling and membrane poisoning.
• Adapt the ED process conditions and stack designs to increase the fouling resilience of the system and increase the potential of this technology towards more challenge bio-based streams
1. A basic electrodialysis model will be implemented in OpenFOAM that includes the major phenomena occurring in electrodialysis (hydrodynamics, ion-transport (Nernst-Planck), water transport and overlimiting current phenomena)
2. An electrodialysis installation will be built to acquire data on fouling related and general state variables. This data will be used to calibrate/validate the model
3. Several fouling models will be developed to described the most prominent and troublesome fouling types when treating bio-based process streams. The fouling types under investigation are,
• Organic fouling (e.g. humic acids)
• Colloidal fouling (e.g. cellulose)
• Membrane poisoning (e.g. multivalent metal complexes)
4. After a thorough validation of the model, system knowledge will be built using well-known modelling tools (e.g. sensitivity analysis)
5. The process conditions will be optimised for these bio-based streams and innovative changes to the electrodialysis stack design will be brought into practice.