PhD in Materials Science for Heat Exchangers in the Food Industry

Context :

The fouling of heat exchanger surfaces with dairy and egg products is a serious health risk. As no satisfactory solution has been developed until now, this project consists in developing materials that have both good food compatibility and anti-fouling properties, and that are resistant to cleaning procedures. In this context, it is proposed to replace stainless steel with carbon-based hydrophobic materials to reduce fouling while improving the energy efficiency of the exchangers. Moreover, some of these materials will also be used to develop Slippery Liquid Infused Porous Surface (SLIPS) biomimetic surfaces with low contact angle hysteresis, which have a high potential for anti-fouling applications.

Work to be performed :

The thesis will consist in designing carbon-based antifouling heat exchangers [1], being at the same time thermal conductor, very resistant to acids and bases, and non-toxic. Three types of materials will be prepared and characterized: (i) bi-continuous hydrophobic composites based on graphite foams of very high thermal conductivity [2]; (ii) vitreous-graphite carbon composites with controlled surface energy and roughness; and (iii) mesoporous carbons with controlled porosity [3-4] to become bases of SLIPS, and treated to become superhydrophobic [5-6]. These studies will therefore require syntheses from thermosetting resins, heat treatments in ovens under inert atmosphere, as well as chemical or physical surface treatments. An essential part of the work will also be devoted to characterisation through a large number of physicochemical analysis techniques (composition, structure, porous texture, surface properties, thermal conductivity, ...) in order to go back to the synthesis and thus to optimise the materials. Numerous exchanges with the consortium partners will be planned for estimating the durability of the materials in real conditions through cleaning-in-place procedures.

References:

[1] Wang, Q.; Han, X. H.; Sommers, A.; Park, Y.; T'Joen, C.; Jacobi, A. A review on application of carbonaceous materials and carbon matrix composites for heat exchangers and heat sinks. International Journal of Refrigeration 2012, 35, 7-26.

[2] Jana, P.; Palomo del Barrio, E.; Fierro, V.; Medjahdi, G.; Celzard, A. Design of carbon foams for seasonal solar thermal energy storage. Carbon 2016, 109, 771-786.

[3] Libbrecht, W.; Verberckmoes, A.; Thybaut, J. W.; Van Der Voort, P.; De Clercq, J. Soft templated mesoporous carbons: Tuning the porosity for the adsorption of large organic pollutants. Carbon 2017, 116, 528-546.

[4] Wickramaratne, N. P.; Jaroniec, M. Phenolic resin-based carbons with ultra-large mesopores prepared in the presence of poly(ethylene oxide)-poly(butylene oxide)-poly(ethylene oxide) triblock copolymer and trimethyl benzene. Carbon 2013, 51, 45-51.

[5] Jana, P.; Palomo del Barrio, E.; Fierro, V.; Celzard, A. Undercooling enhancement of phase-change materials encapsulated in hydrophobised graphitic carbon foams. 2017, In preparation.

[6] Delgado-Sánchez, C.; Letellier, M.; Fierro, V.; Chapuis, H.; Gérardin, C.; Pizzi, A.; Celzard, A. Hydrophobisation of tannin-based foams by covalent grafting of silanes. Industrial Crops and Products 2016, 92, 116-126.