高流速下钯上氢氘的排代研究

在钯氘化物上进行了高流速下氢氘的排代实验。结果表明，氘的排代效率随排代时间的增大而增加；与低压、低流速相比，高流速下排代压力的增加部分弥补了流速增大对氢氘交换速率的影响，因此仍可以得到较高的氘回收率。     

ZSM-5分子筛表面酸碱性质及对Co~(2+)的吸附

采用XRD、FTIR和酸碱滴定等手段对ZSM-5分子筛性质进行研究。采用静态批实验方法研究pH值、离子强度、固液比、平衡时间和Co2+浓度等因素对Co2+在ZSM-5分子筛表面上吸附的影响。结果表明,ZSM-5分子筛对Co2+具有较好的吸附能力和吸附容量;在低pH值下ZSM-5分子筛表面吸附位是以XH、YOH、YO-、YOH2+和XNa形态为主;而在高pH值条件下以YO-和XNa两种形态为主。Co2+在ZSM-5分子筛上的吸附符合准二级动力学;吸附作用受离子强度和pH值影响比较明显。在低pH值下,Co2+主要与ZSM-5分子筛表面发生离子交换作用(X2Co);在高pH值下以表面络合吸附为主(主要形成YOHCo2+和YOCo+两种形态)。     

高纯氘中杂质的低温气相色谱分析

实验研究采用5A分子筛和氧化铝充填色谱柱分别在常温和低温（77K)下对D₂中的O₂、N₂以及H₂、HD等杂质进行定量分析测量，以建立1种准确实用的分析方法。研究结果表明，该方法对H₂、HD的最低检测浓度可达（150～200）×10^－6，能够满足高纯氘制备过程中对杂质的定量分析要求。     

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。     

氘中氢和氘化氢的气相色谱分析法

一、前言氢同位素在原子能工业中的应用是相当广泛的,如热核反应,加速器及气态靶的研究和应用,都具有非常广泛的实际意义。所以国内外有较多的关于氢同位素的气相色谱分析方面的文章。本文主要为加速器及气态靶研究提出的氘(或氢)纯度要求而建立的气相     

低活化铁素体/马氏体钢CLF-1氢氘的渗透行为

低活化铁素体/马氏体钢(RAFM钢)作为聚变堆结构材料中最有前景的候选材料,其氢同位素渗透行为备受关注。采用氢同位素气相驱动渗透的方法,对中国低活化铁素体/马氏体钢CLF-1的氢同位素渗透行为进行了研究,研究了温度、气体压强、样品表面状态等因素对其渗透行为的影响。结果表明:氢、氘在RAFM CLF-1钢中渗透扩散过程为体扩散控制,渗透率与温度的关系式均遵循Arrhenius关系;在实验测试过程中,由于样品表面发生氧化现象和缺陷捕获造成H₂和D₂渗透实验中渗透通量出现下降的现象。     

气相色谱法浓缩氘的研究

采用气相色谱技术建立了一套含氚重水氘浓缩的演示实验装置,用氘-氢（D-H）体系进行实验,结果表明,装置实现了长期、连续、安全的运行。D浓度为O．1％的样品经装置浓缩后得到D浓度为30％的产品,贫化部分D浓度小于10^-5;D浓度为10％的样品经装置浓缩后得到D浓度大于90％的产品。装置对D-H体系的处理容量达到40m%3/d。     

低温吸附法分离氦气流中氢同位素的实验研究

采用穿透曲线法研究了液氮温度下活性炭、碳分子筛和碳纳米纤维对氢同位素的吸附等温线和同位素效应。结果表明：活性炭和碳分子筛都是良好的吸附剂，碳纳米纤维对氢同位素的吸附量太低而不具备工程应用的可能性。实验还对吸附剂进行了改性处理，考察了改性吸附剂对氢同位素的吸附性能。     

高温气冷堆He载气中H2O和CO2吸附净化的实验研究

通过对高温气冷堆Ｈｅ载气中的Ｈ２Ｏ和ＣＯ２在５Ａ分子筛固定床上吸附净化的实验研究，得到了吸附穿透曲线，获得了５Ａ分子筛床对Ｈ２Ｏ和ＣＯ２的动态吸附规律。实验考察了吸附温度、工作压力、杂质浓度、流速及床层高度等因素对Ｈ２Ｏ和ＣＯ２单吸附及共吸附的吸附容量及转效时间的影响，获得了最佳运行参数。实验研究结果表明：净化后Ｈｅ气中Ｈ２Ｏ和ＣＯ２的质量分数低于１０－５，满足了净化系统的要求，为高温气冷堆中５Ａ分子筛固定床装置提供了可靠的设计数据。     

分子筛的结构表征及对痕量氙的动态吸附性能

高效吸附剂是大气放射性氙取样分析系统的核心组成部分之一,为提高探测灵敏度,需获得对大气中痕量氙具有更高吸附性能的吸附剂。研究了10种分子筛对痕量氙的动态吸附性能,利用氮气静态吸附对分子筛的孔结构进行表征,分析了孔结构特征与分子筛动态吸附性能的关系。选择吸附量较高的分子筛,进一步研究了原料气流量、吸附压力和氙浓度对动态吸附性能的影响。结果表明:5A分子筛具有较适合的孔径,对氙的动态吸附性能优于13X分子筛;ZSM-5分子筛可能因晶穴内极性较强和具有较适合的孔径,对氙的吸附能力最强;痕量氙在ZSM-5分子筛上的动态吸附系数随吸附压力的增加而线性增大,随流量增大先下降而后趋于稳定,氙浓度在7.6×10^-9～3.0×10^-8 mol/L范围内对其无明显影响。     

碳基吸附剂对氢同位素的吸附行为研究(Ⅰ)

采用静态压差法研究了液氮温度下碳基吸附剂活性炭（AC）、碳分子筛（601）和碳纳米纤维（CNF）对氢同位素的吸附行为。实验结果表明：601对氢同位素的吸附量为最高，AC次之，CNF最小，并存在明显的同位素效应；吸附量的大小与吸附剂表面活性基团的数量有关；用浓HNO3对碳基吸附剂进行改性处理，在吸附剂表面引入氧杂原子，可增大这类吸附剂对氢同位素的吸附量。     

Adsorption Isotherms of Hydrogen Isotopes on Molecular Sieves 5A at Low Temperature

Cryogenic Molecular Sieve Bed (CMSB) is considered to be applied to the bred tritium recovery system or the helium glow discharge exhaust gas cleanup system of nuclear fusion reactor. Molecular Sieves 5A (MS5A) is one of the most possible candidate adsorbents for CMSB. To design the CMSB, adsorption isotherm of hydrogen isotopes for MS5A must be investigated in liquid nitrogen temperature region (around 77 K) and above, and isotherm equation which can express the experimental data obtained in wide pressure range with good accuracy needs to obtaining. The present authors carried out the experiments using the volumetric method to obtain the adsorption isotherm of H₂ and D₂ for MS5A. Adsorption isotherms were obtained in the pressure range between about lPa and 0.2MPa at 77K (liquid nitrogen), 87K (liquid argon), 113K (isopentane), 143 K (n-pentane), 155 K (ethanol) and 195 K (dry ice/ethanol). Two Sites Langmuir Model was applied to understand adsorption isotherms, and was able to express the experimental observation with fairly good accuracy. The apparent heats of adsorption for two kinds of activated adsorption sites were obtained from temperature dependence of adsorption isotherms. Furthermore, parameters of adsorption isotherms for residual 4 hydrogen isotopes (HD, HT, DT and T2) were estimated using reduced mass.     

碳分子筛上氪、氙的动态吸附及脱附性能

为筛选快速分离Kr/Xe的材料,研究了不同碳分子筛(CMS)对氙(Xe)和氪(Kr)的动态吸附性能与脱附性能,探讨了压力、气体流量、温度等因素对Kr、Xe的动态吸附系数与脱附率的影响。结果表明,碳分子筛Aladdin TDX-01对Xe的吸附容量最大,其次为光复TDX-01,低温时,Aladdin TDX-01对Kr的动态吸附系数大于光复TDX-01。Aladdin TDX-01碳分子筛对Kr和Xe的吸附能力均随压力升高而增强,随着原料气流量增加而减少,动态吸附系数随着温度升高而降低;采用N₂吹扫对Kr、Xe进行脱附,随着N₂流量增大、温度升高,Kr、Xe的脱附时间缩短。Aladdin TDX-01碳分子筛在25℃、100 kPa条件下对Xe的动态穿透吸附系数为1 283 mL/g,在-50℃、100 kPa条件下对Kr的动态穿透吸附系数为474 mL/g。     

氢同位素D、T从气相到液相的氢-水交换实验研究

采用Pt-SDB疏水催化剂和亲水填料混装进行含氘、氚氢气与水的液相催化交换实验，研究反应温度、气体流量和液体流量对D、T转化率以及H-D、H-T的总传质系数Kya的影响。研究结果表明：在相同操作条件下，T的转化率η(H-T)比D的转化率η(H-T)高，H-T的总传质系数比H-D的高；从D、T转化率随气体流量和液体流量的变化趋势可知，气体流量对D、T转化率的影响较大；选择合适的反应温度即可获得较佳的转化率和总传质系数。在实际工艺中，反应温度选为45℃较适宜。     

Molecular Dynamics Study on the Diffusion Properties of Hydrogen Atoms in Bulk Tungsten

Molecular dynamics simulations were performed to study the diffusion behavior of hydrogen atoms in body-centered cubic(bcc) tungsten(W). The energy distribution of a single hydrogen atom in the (001) plane of tungsten lattice was computed. The values of diffusion barriers agree well with other theoretical and experimental results. The interaction between an H atom and a vacancy was simulated, which shows evidence of strong binding effect. The temperature effect on the diffusion behavior of hydrogen atoms was investigated. The critical temperature for an H atom to diffuse in bulk W with and without vacancies were calculated to be 950 K and 450 K, respectively, which is supported by several experimental results. In addition, the diffusion coefficient of hydrogen atoms in tungsten was evaluated and analyzed.     

Molecular Statics Simulation of Hydrogen Defect Interaction in Tungsten

Hydrogen(H) defect interactions have been investigated by molecular statics simulations in tungsten(W),including H-H interactions and interactions between H and W selfinterstitial atoms.The interactions between H and small H-vacancy clusters are also demonstrated;the binding energies of an H,a vacancy and a self-interstitial W to an H-vacancy cluster depend on the H-to-vacancy ratio.We conclude that H bubble formation needs a high concentration of H in W for the H bubble nucleation and growth,which are also governed by the H-to-vacancy ratio of the cluster.The vacancy first combines with H atoms and a cluster forms,then the H-vacancy cluster goes through the whole process of vacancy capture,H capture,and vacancy capture again,and as a result the H-vacancy cluster grows larger and larger.Finally,the H bubble forms.     

Removal of Tritiated Water Vapor by Adsorption

Abstract

Experiments were conducted on the dynamic adsorption of tritiated water vapor, using a column packed with either silica-gel, activated alumina, or molecular sieve 5A. The column was 4 mm I.D. and 5–30 cm long. The runs were performed at 30°–70°C. Tritiated water vapor (HTO) was loaded into the column with a concentration of 170 μμCi/ml, either in pulses of predetermined duration or continuously (breakthrough). The concentrations of H₂O and HTO at column outlet were measured. Particular interest was attached to observing the effect of differences in the pretreatment applied to the adsorbents (whether dried or saturated with water), and in the H₂O partial pressure of the carrier gas. It was found that the adsorption characteristics shown for HTO were not influenced to any appreciable extent by differences in the pretreatment applied to the adsorbents. On the other hand, adsorbent performance depended sensitively on the H₂O pressure in the carrier gas.

Adsorption models for a two-component mixture composed of H₂O and HTO were sought for describing the adsorption mechanism. For the particular case of the molecular sieve 5A, the Langmuir-type mixed adsorption model was found to give values agreeing fairly well with experiment. A model postulating chemisorption of H₂O into hydroxyl group on the adsorbent surface, to be subsequently replaced by tritium, was found suitable for explaining the adsorbent behavior in the case of silica-gel.