林德PSA氢气纯化装置的特点及操作体会

针对不同的原料，ＰＳＡ氢气纯化装置可以有３种工况，采用了４塔复合床、计算机控制等技术，吸附时间可自动调节，操作系数可人为选定。指出了存在的问题及改进措施。     

氢中杂质对钯管纯化器寿命的影响及脱除方法

研究了导致钯管氢气纯化器钯管破裂的原因,着重叙述了采用预处理纯化器等方法大幅度延长钯管使用寿命、保障产气纯度的效果。     

低温液体洗涤纯化氢气的研究

实验证明,在温度为-180～-186℃和压力为2.0～3.0MPa下,采用低温液体甲烷、内烷洗涤氢气,可制得总杂质≤60ppm的纯氢。     

氢气纯化装置燃爆问题探讨

为了保证高纯度产品氢气的连续生产,氢气纯化装置的两个干燥塔需要定期切换干燥和再生工作状态。就如何实现氢气纯化装置的平稳切换,减少压力波动,保证产品指标的稳定,防止放空管出口燃爆现象的发生作了有益的探讨。     

分子筛在空气纯化系统中的应用

介绍了分子筛吸附和再生的原理，分子筛的结构、性能参数、常见规格性能对比以及分子筛再生的机理，分析了影响分子筛吸附性能的因素以及延长分子筛使用寿命的措施。     

金属钯修饰PAn／PTFE复合膜的制备及其氢气响应性的研究

以聚四氟乙烯多孔膜为基膜，采用膜相渗透原位化学氧化聚合法制备了PAn／PTFE复合膜；在该复合膜表面通过电化学沉积金属钯微粒，得到了Pd／PAn／PTFE复合膜，通过测定复合膜在空气中和一定浓度氢气气氛中的V-I特性，表征复合膜对氢气响应性能。实验考察了电沉积过程中沉积时间、氯化钯浓度和盐酸浓度对复合膜性能的影响，当氯化钯浓度为2mol／L、盐酸浓度为0．5mol／L、沉积时间为6min时，复合膜在吸氢前后表现出最大的电流变化值，通过扫描电镜和X射线衍射仪对复合膜进行了表征。初步讨论了该复合膜对氢气表现出电流响应性的机理。     

钯膜制备及渗氢性能研究

随着膜分离技术的不断发展,渗氢用钯基膜由于具有优异的透氢速率、透氢选择性及良好的化学和热稳定性,已被广泛应用于氢提纯分离领域。介绍了钯透氢膜的种类、透氢机理和制备方法,总结了钯膜从最初的纯钯膜、钯合金膜到钯复合膜的发展历程和氢渗透性能研究,并重点介绍了以铌钯复合膜为代表的新型Pd/bcc型复合膜氢渗透性能的研究进展。     

无钯催化铜包覆纳米炭纤维新方法的研究

纳米炭纤维表面包覆上金属铜,可获得新型纳米复合功能材料.研究了利用化学方法,以Cu2 为单质铜来源,锌粉为还原剂,不用贵重金属钯做催化剂,直接在硝酸处理后的纳米炭纤维上包覆铜的新方法.初步分析了镀液中加入引发剂T在纤维表面镀铜的机理;探讨了CuSO4·5H2O的用量、锌粉浓度、施镀温度、施镀时间、配位体种类、用量及引发剂等因素对纤维表面铜包覆层质量的影响,得到了优化的工艺条件:CuSO4·5H2O 6.5 g/L,锌粉1.7 g/L,甘油133 mL/L,乙二醇90 mL/L,酒石酸钾钠8.5 g/L,引发剂T 3.5 g/L,于室温下反应1 h.SEM观察发现,纳米炭纤维表面包覆层较为均匀;EDS表征证实,包覆层确实为铜.     

钯膜与钯膜反应器应用研究进展

综述了钯膜透氢原理及其影响因素,着重介绍了钯膜制备技术及新的改进技术.概述了钯膜和钯基膜在加氢、脱氢、耦合反应中的应用情况,并对其存在的问题和发展前景进行了讨论.     

膜催化技术的应用(Ⅰ)——用氢渗透膜同时实现催化反应和产品分离

本文介绍了膜技术在新的领域——催化反应过程中的应用。特别是对涉氢反应,金属膜或金属多孔膜本身具有催化作用。同时,用氢渗透膜控制氢的传递可以达到选择性加氢的效果,在脱氢反应中产物氢连续地透过膜而移走,可使反应的转化率大大提高。膜技术的有效应用还可同时实现产品分离,即一膜两用。     

多晶硅生产中氢气的来源与净化

简述了多晶硅生产过程中氢气的几个来源,并比较了采用电解、裂解或工业尾气净化回收氢气作为多晶硅生产补充氢气来源的技术、经济性。提出了采用特定吸附剂,变压吸附净化回收可重复利用氢气的新方法。对比了几种氢气的净化回收技术的优势,认为采用变压吸附（PSA）氢气净化工艺过程最优,能耗最低,经济效益最好。     

Shape‐Dependent Interactions of Palladium Nanocrystals with Hydrogen

Elucidation of the nature of hydrogen interactions with palladium nanoparticles is expected to play an important role in the development of new catalysts and hydrogen‐storage nanomaterials. A facile scaled‐up synthesis of uniformly sized single‐crystalline palladium nanoparticles with various shapes, including regular nanocubes, nanocubes with protruded edges, rhombic dodecahedra, and branched nanoparticles, all stabilized with a mesoporous silica shell is developed. Interaction of hydrogen with these nanoparticles is studied by using temperature‐programmed desorption technique and by performing density functional theory modeling. It is found that due to favorable arrangement of Pd atoms on their surface, rhombic dodecahedral palladium nanoparticles enclosed by {110} planes release a larger volume of hydrogen and have a lower desorption energy than palladium nanocubes and branched nanoparticles. These results underline the important role of {110} surfaces in palladium nanoparticles in their interaction with hydrogen. This work provides insight into the mechanism of catalysis of hydrogenation/dehydrogenation reactions by palladium nanoparticles with different shapes.     

Joule Heating a Palladium Nanowire Sensor for Accelerated Response and Recovery to Hydrogen Gas

The properties of a single heated palladium (Pd) nanowire for the detection of hydrogen gas (H₂) are explored. In these experiments, a Pd nanowire, 48–98 µm in length, performs three functions in parallel: 1) Joule self‐heating is used to elevate the nanowire temperature by up to 128 K, 2) the 4‐contact wire resistance in the absence of H₂ is used to measure its temperature, and 3) the nanowire resistance in the presence of H₂ is correlated with its concentration, allowing it to function as a H₂ sensor. Compared with the room‐temperature response of a Pd nanowire, the response of the heated nanowire to hydrogen is altered in two ways: First, the resistance change (ΔR/R₀) induced by H₂ exposure at any concentration is reduced by a factor of up to 30 and second, the rate of the resistance change – observed at the beginning (“response”) and at the end (“recovery”) of a pulse of H₂ – is increased by more than a factor of 50 at some H₂ concentrations. Heating nearly eliminates the retardation of response and recovery seen from 1–2% H₂, caused by the α → β phase transition of PdH_x, a pronounced effect for nanowires at room temperature. The activation energies associated with sensor response and recovery are measured and interpreted.     

类石墨烯碳氮分离膜氢气提纯特性的机理研究

氢气作为一种可再生、高效的清洁能源,在工业生产中必须保证纯度。膜分离技术是一种有效的手段。本工作采用密度泛函理论和分子动力学模拟方法研究了一种新型的类石墨烯碳氮(C₉N₄)分离膜对于H₂的分离提纯性能。密度泛函理论计算结果显示气体在C₉N₄分离膜上的吸附属于物理吸附。C₉N₄分离膜表现出极高的H₂渗透率和优异的选择性,300 K下H₂渗透率达到1.89×10^-5 mol·m^–2·s^-1·Pa^-1,H₂/CH₄的选择性达到10²⁴。分子动力学模拟的结果也显示C₉N₄分离膜具有良好的H₂分离特性。