The Study On Hydrogen Isotope Separation By Hydrogen-Water Liquid Phase Catalytic Exchange

Three hydrogen isotopes, protium, deuterium, tritium, have been widely used. Hydrogen can be widely used in petrochemical industry, electronic industry and metallurgical industry. Deuterium and tritium have been played an important role in nuclear energy and military affairs. The subject in separation and purification of deuterium and tritium has great significance. Among the many separation methods of hydrogen isotope, H2-H2O liquid catalytic exchange has been under attention of scholars from different countries, because it's high efficiency, non-toxicity and no corrosion. The selection of catalyst is the key to hydrogen isotope exchange reaction between hydrogen gas and liquid water. Now, many countries have catalysts for exchange between hydrogen and water, but the details of preparing catalyst keep secret. So, we should prepare a catalyst which is fit for engineering application and has high active and stable. The method of H2-H2O liquid catalytic exchange has many potential applications, such as producing and upgrading heavy water, producing light water and removing tritium from light water and heavy water, recovery tritium for fusion reactor.This paper mainly presents the design and preparation of catalysts used in hot tower and cold tower, the characterization and the activity of catalysts, the process of H2-H2O liquid phase catalytic exchange (LPCE), and the production of deuterium depleted water by LPCE.1. Two kinds of catalyst are prepared in this paper, one is Pt/SDB, and the other is Pt/PTFE. The active constituent is platinum. The Pt/SDB catalyst is prepared by Pt directly on the hydrophobic resin SDB with uniform pore dispersion, and its main use is in low temperature exchange. The Pt/SDB catalyst support is fashioned by droplet agglomeration method, using a benzene solution of divinylbenzene to form small spheres. The quality of the SDB is directly affected by the proportions of raw material, the rate of agitation and the time of agitation. We research these factors, and then fish out the best synthesis condition. The Pt/PTFE catalyst is prepared by Pt directly supported on PTFE with pore dispersion, and its main use is in high temperature exchange. The Pt/PTFE catalyst support is prepared by compression moulding forming. The quality of the PTFE is directly affected by the ration of porogen, the pressure and time of preformed, the temperature of sintering.2. For testing the performance of the catalysts, we use gas chromatography to analyse the content of deuterium. We carried out the hydrogen-water isotope exchange reaction in co-current and counter-current in the trickle bed. We tested the activity of the catalysts and discussed the effect of operating conditions on the activity, such as reaction temperature, flow rate of hydrogen, flow rate of water, the height of catalytic bed, and so on. The activity order is Pt/SDB-1>Pt/SDB-2>Pt/PTFE. The experiments about lifetime indicate that the hydrophobic catalysts are good in wet-proffed and stability.3. In this paper, we produce deuterium depleted water by liquid phase catalytic exchange between hydrogen and water. We design an equipment for producting deuterium depleted water and select Pt/SDB and Pt/PTFE as catalysts. On the basis of technological process, we carry out the theoretical calculation and experiment, and compared the results. The experimental result demonstrates that the deuterium content is 126 ppm after 30-80℃dual-temperature exchange.