Performance of Structured Packing for the Deuterated Water Distillation Process at Above Atmospheric Pressure

Abstract

The National Research and Development Institute for Cryogenics and Isotopic Technologies (ICSI) was established in 1970 for research focused the industrial pilot plant. ICSI was created with the purpose of developing the heavy water production technology needed mainly for the operation of the CANDU reactors that equip the Cernavoda Nuclear Power Plant in Romania. This technology has been demonstrated and has been successfully transferred to the heavy water production plant. The accumulated experience in the field of isotopic separation allowed for the development of a second pilot plant, also for the purpose of heavy water, but this time for the purpose of separating deuterium and tritium for the recovery of tritium, mainly from the tritiated heavy water of the CANDU reactors. This experimental pilot is based on a technology that combines two hydrogen isotope separation processes: liquid-phase water-hydrogen catalytic isotopic exchange and hydrogen isotope cryogenic distillation. The success of the separation process consists of the technical solution given to the exchange area, its geometry (distillation-isotopic exchange), and last but not least, the performance of the hydrophilic packing, respectively, of the catalyst. Thus, an extensive research program was initiated and carried out over many years for the development of mixed catalytic packages consisting of a hydrophobic Pt/carbon catalyst (with different concentrations of platinum up to 2%) and hydrophilic packing (stainless steel or phosphorous bronze) manufactured within ICSI and made in different configurations (successive layers, random or structured). This program for the improvement of catalytic packages continues by implementing new solutions regarding the improvement of materials that ensure a large contact surface between the liquid and vapors, respectively, vapor and gas, thus increasing the isotopic separation performance. This paper presents an experimental analysis of two types of hydrophilic stainless steel packings developed for the purpose of separating hydrogen isotopes by water distillation to be used in the manufacture of mixed catalytic packages for the catalytic isotopic exchange process. This paper refers to the experiments performed with deuterated water on the hydrophilic packing in conditions of total reflux. The experiments were performed on a column equipped with two types of hydrophilic packing.