氪氙混合气的分离

惰性气体氪和氙主要用于光技术、技术物理。激光技术、医学及其它领域。惰性气体在大气中的含量微乎其微(0.00014％Kr,0.000088％Xe)。由于惰性气体的物理性质,在低温分离空气时,它们将聚集在液氧中。分离氪和氙需采用大型空分设备来实现。此外,制备这些惰性气体的原料可以是合成氨尾气分离甲烷馏份。无论是第一种情况还是第二种情况,分离和浓缩惰性气体的结果都是得到氯氙混合气。该混合气中,氪和氙的含量按苏联国家标准ГОСТ10218—77规定,应不低于99.5％。分离这样的原料气,可制备出纯的和高纯的氪气和氙气,以适用于现有的标准和要求。     

林德公司稀有气体氪氙分离装置全球最大

<正>稀有气体,称作惰性气体、贵重气体,俗称黄金气体,它在空气中含量很少,其分离提取是世界性的难题。常说的稀有气体有6种:氦(He)、氖(Ne)、氩(Ar)、氪(Kr)、氙(Xe)和具放射性的氡(Rn)。其中的氪和氙,是半导体、高纯金属工业、化学成分分析、特殊电光源等应用领域的重要原料,或工艺过程中必须采用的保护气体,在现代科技与工业发展中有十分重要的作用。     

日本稀有气体的市场动向

稀有气体在元素周期表中属0族元素,它们有氦(He)、氖(Ne)、氩(Ar)、氪(Kr)、氙(Xe)、氡(Rn),它们都是一价原子的气体,性质非常稳定,所以,也称作惰性气体。如表1所列,它们在空气中的含量,一般情况下,氩最多,占0.9％,氖18ppm,氦5ppm,氪1ppm,含量非常少,所以,也叫贵重气体。除氦和氡外,都可由浓缩空气而获得。     

空分装置提高氪氙提取率的改进操作

通过对空分装置Kr/Xe提取流程的分析,结合实际操作经验提出了两项提高Kr/Xe提取率的二氪塔改进操作。     

河钢邯钢气体外销利润破亿促进我国气体产业健康发展

正稀有气体(noble gases)是指元素周期表上的18族元素(IUPAC——国际理论和应用化学联合会新规定,即原来的0族)。在常温常压下,它们是都是无色无味的单原子气体,很难进行化学反应。天然存在的稀有气体有6种,即氦(He)、氖(Ne)、氩(Ar)、氪(Kr)、氙(Xe)和具有放射性的氡(Rn222)。空气中的稀有气体有He、Ne、Ar、Kr、Xe和Rn。目前空分装置能够生产和提取He、Ne、Ar、Kr、Xe。     

气瓶安全与检验问答(十七)

问:惰性气体与非助燃性气体有何区别,氮气和二氧化碳属于惰性气体吗?答:从化学概念讲,氮和二氧化碳不属于真正的惰性气体,而称为惰性气体的是指化学周期表中的零族元素,氦、氖、氩、氪、氙、氡6种气体。这6种气体都是单原子气体,其电子层结构都处于稳定状态,化学活泼性极弱,难以与其它元素化合。它们在空气中含量少,因而又被称为稀有气体。每1000Ｌ空气中约含有9 3ｍＬ氩、18ｍＬ氖、5ｍＬ氦、1ｍＬ氪、0 8ｍＬ氙。稀有气体的惰性不是绝对的,如以氙为主体的含氟含氧等化合物及氪、氡个别化合物就是例证。如把氮和二氧化碳与惰性气体作一…     

贮氢合金在气相色谱法测定高纯氢中痕量杂质的应用

应用贮氢合金可测定氢气中谐如氖、氩、氮、氪、甲烷和氙等痕量杂质。该系统由气相色谱仪与充填有贮氢合金的前置柱组成。在室温和载气压力下,贮氢合金有效地捕集氢。采用光电离检测器,检测极限可达:Ne、Ar、N_2、Kr、CH_4和Xe分别是4.7、0.02、0.02、0.01、0.01和0.01ppm。     

氪,氙提取技术的新进展

综述了制取氪、氙技术的发展方向,详细介绍了在制取氪、氙过程中如何提高过程安全性和氪、氙提取率的新方法,对新老流程作了比较,运用具体数据对氩再循环流程、氮置换流程、用氧清除甲烷流程及从供给原料液中提取氰、氙流程实例作了具体分析与总结。     

聚酰亚胺类共价有机骨架多孔材料的研究进展

聚酰亚胺类共价有机骨架与常规的多孔材料相比,具有较高的机械强度,良好的化学和物理稳定性以及合成的多样性以及孔尺寸的可控性,能够广泛应用于非均相催化,分离和气体储存等领域,因而有望成为一种新型的具有发展潜力的多孔材料。从聚酰亚胺类共价有机骨架中多孔材料的合成、性能等方面对近年来国内外的研究状况进行了详细的阐述,并在此基础上对该方向的前景进行了展望。     

氪氙稀有气体的低温分离模拟

为了回收利用液氧中的氪和氙,采用PR气液平衡状态方程,使用HYSYS软件对氪氙浓缩塔内的精馏分离进行了模拟计算,得出了塔内的温度变化曲线和氧、氪、氙组分的分布曲线,提出利用塔内的平均温度控制塔内精馏工况,并对氪氙浓缩塔的设计提出建议。     

What CO2 well gases tell us about the origin of noble gases in the mantle and their relationship to the atmosphere

Study of commercially produced volcanic CO2 gas associated with the Colorado Plateau, USA, has revealed substantial new information about the noble gas isotopic composition and elemental abundance pattern of the mantle. Combined with published data from mid-ocean ridge basalts, it is now clear that the convecting mantle has a maximum (20)Ne/(22)Ne isotopic composition, indistinguishable from that attributed to solar wind-implanted (SWI) neon in meteorites. This is distinct from the higher (20)Ne/(22)Ne isotopic value expected for solar nebula gases. The non-radiogenic xenon isotopic composition of the well gases shows that 20 per cent of the mantle Xe is 'solar-like' in origin, but cannot resolve the small isotopic difference between the trapped meteorite 'Q'-component and solar Xe. The mantle primordial (20)Ne/(132)Xe is approximately 1400 and is comparable with the upper end of that observed in meteorites. Previous work using the terrestrial (129)I - (129)Xe mass balance demands that almost 99 per cent of the Xe (and therefore other noble gases) has been lost from the accreting solids and that Pu-I closure age models have shown this to have occurred in the first ca 100Ma of the Earth's history. The highest concentrations of Q-Xe and solar wind-implanted (SWI)-Ne measured in meteorites allow for this loss and these high-abundance samples have a Ne/Xe ratio range compatible with the 'recycled-air-corrected' terrestrial mantle. These observations do not support models in which the terrestrial mantle acquired its volatiles from the primary capture of solar nebula gases and, in turn, strongly suggest that the primary terrestrial atmosphere, before isotopic fractionation, is most probably derived from degassed trapped volatiles in accreting material.By contrast, the non-radiogenic argon, krypton and 80 per cent of the xenon in the convecting mantle have the same isotopic composition and elemental abundance pattern as that found in seawater with a small sedimentary Kr and Xe admix. These mantle heavy noble gases are dominated by recycling of air dissolved in seawater back into the mantle. Numerical simulations suggest that plumes sampling the core-mantle boundary would be enriched in seawater-derived noble gases compared with the convecting mantle, and therefore have substantially lower (40)Ar/(36)Ar. This is compatible with observation. The subduction process is not a complete barrier to volatile return to the mantle.     

提高30000m~3/h空分设备氪氙产量的理论探讨及操作实践

针对武钢30000m3/h空分设备氪气、氙气产量不达标的现象,从精馏理论和实际操作的角度,分析了其中原因;采取相应措施,使氪气、氙气产量超过了设计值;最后,提出了在挖掘空分设备潜力及保证设备安全运行方面值得研究的问题。     

STM Observations of 2D Kr and Xe Adsorbed on Graphite

Crystalline structures of two dimensional rare-gas solids physisorbed on a graphite surface are studied with a low-temperature scanning tunneling microscope (STM) at T=4 K. We have obtained atomically resolved STM images of monolayer krypton (Kr) for the first time as well as those of xenon (Xe). It was observed that the 2D structure of Xe is destroyed with small tip-sample separation. Distinct changes in the local density of states were observed in tunneling spectra after the adsorption. For a multi-layer Xe film, a characteristic telegraph pattern of the tunneling current was also observed, which probably indicates single atom dynamics.     

空分设备中氪氙稀有气体提取精制技术

介绍了从大型空分设备中提取及精制氪、氙稀有气体的工艺原理和技术特点,综述了在制取氪、氙过程中如何提高过程安全性和氪、氙提取率等方面的技术进展,并对我国氪、氙稀有气体的生产现状与前景进行了概述。     

The solubility of inert gases in liquid-metal heat-transfer agents

In the case of neutron irradiation of some metals, many of the nuclear reactions (n, p), (n, α), and (n, 2n) lead to the formation of inert gases [1]. The formation of isotopes of helium in these reactions, as well as of isotopes of xenon¹³³Xe and krypton⁸⁵Kr, as the products of fission of fuel in fast neutron reactors has a considerable effect on the heat-transfer and hydrodynamic characteristics of the heat-transfer agents (for example, alkali metals and alloys on their basis), this necessitating the investigation of the solubility of inert gases in liquid metals [2]. In addition, note the considerable effect of dissolved inert gases on the thermal properties of liquid metals at high temperatures, especially, in the critical point region. The paper presents the results of calculation of the solubility of inert gases (helium, argon, krypton, xenon) in liquid alkali metals atT=600 K andP = 0.1MPa.     

Phase transitions in adsorbed layers VIII: Evaluation of phase diagrams for monolayers of argon,krypton and xenon adsorbed on graphite

The theory of monolayer adsorption of simple atomic gases on crystalline solid is presented and is used to calculate the phase diagrams for noble gases adsorbed on graphite. It is shown that the third-order correction terms to the interaction energy between adsorbed atoms must be included in order to obtain results that are in agreement with experimental data. It is also demonstrated that our theory predicts the formation of a commensurate two-dimensional solid phas e for krypton monolayer films and an incommensurate two-dimensional solid phase for both argon and xenon monolayer films on graphite.     

Titanium surface layers after irradiation with swift Kr and Xe ions

This paper presents the test results of the swift krypton (240 MeV) and xenon ion (130 MeV) irradiation influence on the titanium surface layer properties. These ions change the titanium surface topography in different ways. The irradiation contributes to the creation of a new phase in the surface layer. Radiation damage effects on the friction coefficient, wear, and microhardness of titanium after krypton and xenon ion irradiation were studied. Krypton irradiation does not influence the microhardness of the titanium. After xenon irradiation with a fluence of 1 × 10¹⁸ ion/m² the microhardness increases by 13%; further increases of the fluence gradually reduce the microhardness of the surface layer. Swift Kr and Xe ion irradiation does not influence the friction coefficient of the titanium surface.     

建立一种氪氙原料气中氪气和氙气含量的分析方法

介绍一种全新的氪氙原料气中氪气和氙气含量的分析方法。该方法能够准确测定生产过程中氪氙原料气中氪气和氙气的组分含量,有效降低生产能耗和提高产品产量。     

Switchable Xe/Kr Selectivity in a Hofmann-Type Metal–Organic Framework via Temperature-Responsive Rotational Dynamics

The development of adsorbents for Kr and Xe separation is essential to meet industrial demands and for energy conservation. Although a number of previous studies have focused on Xe-selective adsorbents, stimuli-responsive Xe/Kr-selective adsorbents still remain underdeveloped. Herein, a Hofmann-type framework Co(DABCO)[Ni(CN)₄] (referred to as CoNi-DAB ; DABCO = 1,4-diazabicyclo[2,2,2]octane) that provides a temperature-dependent switchable Xe/Kr separation performance is reported. CoNi-DAB showed high Kr/Xe (0.8/0.2) selectivity with significant Kr adsorption at 195 K as well as high Xe/Kr (0.2/0.8) selectivity with superior Xe adsorption at 298 K. Such adsorption features are associated with the temperature-dependent rotational configuration of the DABCO ligand, which affects the kinetic gate-opening temperature of Xe and Kr. The packing densities of Xe (2.886 g cm⁻³ at 298 K) and Kr (2.399 g  cm⁻³ at 195 K) inside the framework are remarkable and comparable with those of liquid Xe (3.057 g cm⁻³) and liquid Kr (2.413 g cm⁻³), respectively. Breakthrough experiments confirm the temperature-dependent reverse separation performance of CoNi-DAB at 298 K under dry and wet (88% relative humidity) conditions and at 195 K under dry conditions. The unique adsorption behavior is also verified through van der Waals (vdW)-corrected density functional theory (DFT) calculations and nudged elastic band (NEB) simulations.