Investigation of water separation capabilities of demisters integrated with microstructured surfaces

Abstract

Demisters with high water separation efficiencies play an important role in performance enhancement of thermal desalination. Bio-inspired, microstructured surfaces have been highlighted due to the potential to considerably increase water separation by enhancing water capturing and transporting features. However, experimental investigation on the performance enhancement of the demisters with those functional surfaces is still lacking. Herein, we demonstrate water collection and separation characteristics of the large-scale demisters integrated with hybrid microstructured surfaces. Particularly, the hybrid microstructured polypropylene surfaces to possess the vertically-aligned spiky cone arrays along with multiple sets of open-type microchannels are successfully fabricated in uniform manner by using an injection molding process. The fabricated hybrid microstructured surfaces perform twice and up to 3.2 times higher water collection than the control planar surfaces in low-speed and high-speed air flows, respectively, owing to their enhanced water capturing and transporting capabilities by the capillary pressure generated by the microstructures. As a model study, the inner surfaces of the axial cyclone-type demister ducts are modified with the hybrid microstructured surfaces, leading to up to 12 % enhancement of the water separation efficiencies of the demisters, compared to the control planar surface demister in high-speed air flow.