Hydrophilic modification of packings for water distillation and its mass transfer performance

Water distillation is proved to be an effective method for the recovery of tritium from nuclear power plant drainage. In addition to the geometry and material, the surface wettability of the internals also affects the mass transfer performance of the packings. In this paper, we prepared a superhydrophilic coating on the surface of copper packings by a simple method, to increase the intensity of gas-liquid interface, and thus intensifying the heterogeneous mass transfer process. Scanning electron microscopy, atomic force microscopy, X-ray diffraction and X-ray photoelectron spectroscopy were employed to study the physical and chemical condition changes of the packings surface. Measured by ultraviolet fluorescence imaging technology, the wetted area of the copper wire mesh corrugated packing increased by 58.0 % - 91.2 %. The mass transfer performance for separating H2OHTO mixture with tritium activity of 12.9 MBq/kg is conducted in the total reflux mode distillation column. With varied measured conditions, the height equivalent of theoretical plate (HETP) drops from 3.5 - 5.8 cm to 1.9 - 2.4 cm after the packing surface modification, which indicates that the mass transfer performance has been sufficiently improved.