Bram De Jaegher

PhD Student

Prof. dr. ir. Ingmar Nopens - Ghent University
Prof. dr. ir. Arne Verliefde - Ghent University
Wim De Schepper - VITO

Research background

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.

Research objective

•    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

Research methodology

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. 

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