热循环吸附法分离氕、氘的研究

对热循环吸附法(TCAP)全回流模式和生产模式下的氕 氘分离实验进行了研究。全回流模式下,主要考核了初始进料比、冷/热循环温度、进料位置对分离效果的影响。结果表明,原料气体从分离柱中部进料时,初始进料比相对越大,冷/热循环温差越大,分离效果越好;而从回流柱进料时,分离效果相对更好。在几组实验中,回流柱初始进料为90%、冷/热循环温度分别为56 ℃/290 ℃的一组效果最好。生产模式下,由于分离柱中气阻较大,有可能影响氕、氘的分离效果,这部分实验还有待继续进行。     

低温精馏氢同位素分离全回流模式研究

为探求全回流模式下低温精馏氢同位素分离过程中有关操作参数的内在联系,研究了再沸器加热功率对脱氘率、床层压降、液氢液位等的影响。当再沸器加热功率从5W增加到12.4W时,脱氘率从88%增加到99.6%,脱氘率与再沸器加热功率基本呈线性关系。随再沸器加热功率的增加,液氢液位下降,床层压降增加,但在该功率范围内未出现液泛现象。随加热功率增加,精馏柱操作压力从100kPa升高到190kPa,冷凝器和冷头为提供更多冷量而温度降低。     

两种TCAP分离材料分离H-D的比较

对TCAP的两种常用分离材料Pd/K和Pd/Al2O3进行研究对比。分别对Pd/K和Pd/Al2O3的钯含量、表面形貌、晶体结构、饱和吸氢量进行了测试比较,并采用901.7g w(Pd)=(40.8±0.1)%的Pd/K和1 558gw(Pd)=(45.3±0.1)%的Pd/Al2O3分别填装TCAP分离柱,对Pd/K和Pd/Al2O3在分离H-D方面进行了研究对比。结果表明,在分离H-D方面,Pd/Al2O3明显优于Pd/K。     

双钯柱自置换色谱法浓缩氘的实验研究

采用双钯柱自置换色谱法建立了1套氘浓缩实验装置。研究并讨论了该装置对氘的富集效果。实验结果表明：氘丰度为2.0%和5.0%的样品经富集后,最大氘丰度分别达到31.6%和67.3%。该装置结构简单、操作方便,适宜对低氘丰度的氢同位素气体进行有效富集。     

载钯硅藻土吸氕/氘动力学同位素效应

恒温等容条件下,通过p-t曲线测量,研究在223~393K范围内载钯硅藻土(Pd/K)吸氕、氘动力学特性。应用反应速率分析方法计算了反应速率常数,得到了Pd/K吸氕、氘反应活化能。动力学计算结果显示:在整个温度范围内,载钯硅藻土与氕、氘反应明显分为两个温度段。低温段(223~313K),载钯硅藻土吸氕、氘反应速率常数随温度升高而增大且吸氕反应速率大于吸氘反应速率,吸氕、氘反应活化能分别为19.5、19.2kJ/mol;高温段(313~393K),载钯硅藻土吸氕、氘反应速率则随温度升高而减小,氕、氘反应活化能分别为:-18.6、-12.1kJ/mol。测试结果表明,载钯硅藻土吸氕、氘反应存在显著的动力学同位素效应且同位素效应依赖于温度的变化。     

双柱周期逆流法分离氢同位素

将具有正、反氢同位素效应的2种贮氢材料Pd和LaNi_4.7Al_0.3结合,组成双分离柱,测试了原料气氘原子摩尔分数为0.5和0.1的2种混合气体的流出曲线,并进行了周期逆流方式的分离实验。实验结果表明,该分离方法具有较高的分离效率,产品气的氘原子摩尔分数一般大于0.995。改进方式后分离氘原子摩尔分数为0.1的原料气,产品气的最大氘原子摩尔分数为0.998,最大氘富集比为9.98,氘的回收率为92.5%,尾气中氢原子摩尔分数大于0.996,全分离因子大于120 000。     

钯在氢同位素分离和纯化工艺中的应用

在迄今所知的金属-氢体系中，钯氢体系的同位素效应最强，因此，钯被广泛用于氢同位素处理工艺中。文章简述了钯氢体系的同位素效应，综述了钯及其合金在氢同位素分离和纯化工艺中的主要应用及其发展。     

载钯硅藻土的制备及其吸放氢性能研究

采用PdCl2溶液以浸渍还原法制备了载钯硅藻土复合材料(Pd/K),并对Pd/K复合材料中钯的分布状态,以及Pd/K复合材料的p-C-T曲线、热力学、动力学及循环吸放氢性能进行了研究。结果表明:与纯钯相比,载钯硅藻土样品吸氢量有所降低,吸放氢平台压稍有升高,平台斜率增大,其吸氢速率比纯钯的高1倍以上;吸放氢焓变值降低,熵变值升高。经2000次吸放氢循环后,载钯硅藻土的样品饱和吸氢量和吸氢速率未改变,粉化率为3.6%(质量分数)。     

Multi-component Adsorption Characteristics of Hydrogen Isotopes on Synthetic Zeolite 5A-type at 77.4K

The pressure swing adsorption (PSA) method, operating rapid desorption, has become applied to medium-massive air-component separation. In this study, with the aim of applying the PSA method to a hydrogen isotope separation process, the multi-component adsorption characteristics of H₂-D₂ or H₂-HD-D₂ on a synthetic zeolite at the liquid nitrogen temperature 77.4 K are investigated by using a volumetric apparatus, where the system effects of thermal transpiration and diffusion are taken into account. The adsorption isotherms for pure H₂ and D₂ are shown in a wide pressure range between 10^-2 and 10⁵Pa. The isotherms are closely approximated by an error functional expression proposed here. The separation factors resulting in adsorption are measured in a wide range of amount adsorbed. The separation factors of D₂/H₂ are estimated in accordance with the ideal adsorbed solution theory using the adsorption isotherms for H₂ and D₂. The behavior of the estimated factors agrees with that of the experimental ones. The result suggests that values around 3 are expectable for the factors of D₂/H₂ at amounts adsorbed roughly between 0.01 and 1 mol/kg.     

Measurement of HETP of SUS Dixon Ring and Porcelain Packing in Small-Scale Water Distillation Column for H2O-HTO Isotope Separation

Series of water distillations in a total reflux mode have been performed in a 100cm height column of 1.6cm I. D. in order to measure values of HETP for various packings, that is, one brass or three SUS Dixon rings and three porcelain packings. The HETP were measured by changing the vapor flow rate within the column. The SUS Dixon ring of 1.5 mm diameter and the porcelain packing of 1.2 mm O. D. had a small HETP (～5cm), but could not meet a large vapor flow rate because of a large pressure drop. The SUS Dixon ring of 6.0 mm diameter had a small HETP (～6cm) in the vapor flow rate under 2g/min, but the HETP value increased with increasing the vapor flow rate. The pressure drop for the ring, however, was almost constant in the range of these measurements.