Gas separation by a Pd-plated alumina membrane for a small-scale emergency atmospheric detritiation system

针对小型应急大气有害系统(ADS)，进行了镀Pd氧化铝膜分离氢气和水蒸气的实验研究，并对一体化ADS进行了数值模拟，得到了以下结果：(1)用气体分离膜部分替代一体化ADS，对其水汽和氢气分离特性进行了数值模拟。从ADS气体分离效率的角度来看，在横流、逆流、并流和完全混合流中，逆流是最有前途的，对于水蒸气、氚和氮气三组分体系，水蒸气优先渗透到气体分离膜入口附近。确定了最佳切割条件。(2)纤维素醋酸酯膜和聚酰亚胺膜的水蒸气透过率和氢气透过率与以往报道的值一致。实验结果表明所建立的实验装置具有良好的性能。(3)为了研究Pd膜的渗氢性能，在Zr2Fe颗粒上进行了化学镀Pd。在无氧气氛中，在室温下，氢气能有效地透过Pd膜，而在含氧气氛中，氢气在Pd膜上转化为水蒸气。(4)在临界过饱和条件下，水蒸气透过ADS气体分离膜进行降凝，在气流中产生水雾。为了建立小型应急大气有害系统，对气体分离膜、化学镀Pd技术和蒸气升华系统进行了综合研究，证明系统各部件性能良好。

I conducted an experiment of the hydrogen and water vapor separation by a Pd-plated alumina membrane for a small-scale emergency atmospheric detritiation system (ADS) and carried out numerical simulations of an integrated ADS.The following results were obtained.(1) Water vapor and hydrogen separation characteristics were numerically simulated for the case of an integrated ADS partially replaced by the gas separation membrane. The counter-current flow was found to be the most promising among the cross flow, counter-current flow, co-current flow and complete mixing flow from a viewpoint of the gas separation efficiency of ADS.Water vapor preferentially permeated near the inlet of the gas separation membrane for the case of the three-component system of water vapor, tritium and nitrogen. The best cut condition was determined.(2) The water vapor and hydrogen permeabilities of a cellulose-acetate membrane and a polyimido membrane agreed with values reported in the past elsewhere. This results shows a good performance of the experimental apparatus built here.(3) Electroless Pd plating on Zr_2Fe particles was conducted for the investigation of the hydrogen permeation performance of a Pd film. The Pd plating was stable even in heating up to 800ﾟC.Hydrogen effectively permeated through the Pd film at around room temperature in oxygen free atmospheres, while hydrogen gas changed to water vapor on Pd film in atmospheres including oxygen.(4) Mist formation occurred in gas streams at the critical supersaturation condition when water vapor permeating through the gas separation membrane of ADS was cooled for desublimation from the streams.In order to establishe a small-scale emergency atmospheric detritiation system, the gas separation membrane, the electroless Pd plating technique and the vapor desublimation system was integrally investigated and each system component was proved to perform expected characteristics.