Development and thermal performance of a thermoplastic-graphite-composite based plate heat exchanger for use in corrosive media

Abstract

Polymer composites based on thermoplastics and thermally conductive fillers can compensate for the disadvantage of poor thermal conductivity of pure polymers and thus serve as feedstock for heat transfer materials in corrosive environments up to 200°C. This study demonstrates the production of a gasketed plate heat exchanger made of chevron plates based on composites. The novel production process presented allows the transfer of embossing patterns known for metals to polymer composites with processes suitable for mass production. The embossed polypropylene-graphite and polyphenylene sulfide-graphite sheets with a surface area of 0.011 m2 and thicknesses below 2.5 mm achieve thermal conductivities of up to 2 and 2.4 W/mK, respectively. The experimental results show that at wall thicknesses of 0.85 mm, overall heat transfer coefficients of 1280 – 1850 W/m2K for water-water heat transfer and Reynolds numbers of 600-1600 are achieved. Considering the low density of the thermal plates produced, this ensures comparable performance with metallic materials over a wide range of process conditions (Re = 200 - 8000) for the same wall thicknesses. A screening of the fouling susceptibility of the materials shows sensitivity to calcium sulfate fouling, however, qualitative analysis indicates that this is due to flow maldistribution and not the actual materials.

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