新型氨分解制氢装置

以氨分解制氢取代水电解制氢,在经济上具有可行性,本文作者对氨分解装置进行了改进,并在浮法玻璃行业制氢中应用获得成功。     

氨分解制氢工艺在浮法玻璃生产中的广泛应用

本文就目前许多浮法玻璃厂广泛采用氨分期制氨工艺。残氨对锡槽的影响及液氨中杂质对玻璃的影响等问题给予说明。并就氨分解制氢工艺的特点。说明氨分解制氢工艺可使浮法玻璃厂获得经济效益。     

略谈氨分解制氢工艺

自80年代起，我国的平板玻璃工业发展较快。浮法工艺已成为平板玻璃制造最主要的工艺。浮法玻璃成形是在锡槽中进行的，为了防止锡槽中高温锡液的氧化，锡槽空间必须充满并不断补充作为保护气体的氮、氢混合气体。在保护气体中，氢气的含量一般占4—7％，成分比例因厂家各异。氢气制取     

钯膜反应器制氢研究进展

钯膜与水蒸汽重整反应器集成使反应与分离一体化,在降低装置投资成本和节能降耗方面具有明显优势和发展前景,受到研究者的青睐。综述了固定床和流化床钯膜反应器规模验证方面的研究进展,并指出钯膜反应器制氢工业化进程中可能会遇到的问题和需要解决的问题。     

氨分解制氢在浮法玻璃生产线上的配置与使用

90年代初,笔者曾参与了浮法玻璃生产线上氨分解制氢设备的开发、研制、安装、调试等工作。整个工程项目只是因为净化系统在设备制中偏离设计要求,而在调试时出现其内部过热以致将分子筛烧熔（笔者曾在《低温与特气》杂志中做过介绍）,其它基本上比较顺利。目前,氨分解制氢设备在浮法玻璃生产线上已运行了近10年,那么设备总体性能的好坏,各单位的使用现状及配置是否合理,目前还存在哪些问题等,笔者想就此谈点看法。     

稳定氨分解制氢生产的技改措施

本文通过耀华国投公司制氢站的生产实践,介绍了在氨分解制氢生产中采取的一些技改措施,对稳定生产节能降耗起到了较好的作用。     

钯膜及其在涉氢反应中的应用研究进展

综述了钯膜应用的研究进展,重点阐述了钯膜的透氢机理、制备方法、表征方法及在涉氢反应中的应用,总结了钯膜透氢性能的影响因素,指出了钯膜在分离和催化反应中面临的挑战,并对钯膜反应器的应用发展前景进行了展望。     

氨分解制氢镍基催化剂研究进展

氨分解制氢清洁高效,易于工业化使用,是一种极具前景的便携式制氢方法。镍作为氨分解非贵金属催化剂中性能最好、应用最广的催化剂,但仍存在低温活性低、易烧结等问题亟需改进。本文概括了氨分解反应的反应机理、动力学和热力学,综述了近年来国内外氨分解镍基催化剂的研究现状。研究者从镍金属活性中心调控出发进行研究,发现调节镍粒子尺寸、加入第二金属(Fe、Co、Mo等)、载体(Al₂O₃、SiO₂、分子筛等)、助剂(碱土金属、稀土金属等)以及设计核壳结构进行调控,可提高镍金属的分散性和抗烧结能力。本文在以上基础上提出了镍基催化剂的改进措施和未来发展方向,以期为进一步设计出低温高活性镍基催化剂提供依据。     

氨分解设备及其中毒剖析

对氨分解制氢工艺中催化剂中毒现象进行分析 ,指出造成中毒的因素 ,并提出了硫中毒的后处理办法和预防措施。     

甲醇/H2O/H2O2/1,3,5-三甲苯/磷酸三辛酯五元系液液平衡的实验数据

测定了常压、 4 0℃下甲醇 /H₂ O/H₂ O₂ /1,3,5 -三甲苯 /磷酸三辛酯五元系液液平衡数据 ,分别用UNIQUAC模型和NRTL模型对实验数据进行了关联 ,取得了较满意的结果     

硫酸水溶液中3-甲基吡啶透过Nafion膜的渗透

引　言Nafion膜是美国Dupont公司开发的一类全氟磺酸型阳离子交换膜, 由疏水性骨架与亲水性磺酸基团组成, 具有优良的离子选择透过性和化学稳定性, 广泛用于膜电解制碱工业. 在质子交换膜燃料电池、膜分离、有机电合成等领域的应用研究进展迅速[1~5]. 在直接燃料电池中, Nafio     

CH4-CaSO4和H2S-Fe2O3反应体系的热力学和动力学研究

The destruction of hydrocarbon in deep carbonate diagenetic environment is one of problems on the formation of oil and gas. Organic-inorganic reactions in the process of TSR(Thermochemical Sulfate Reduction) are the main reason to make disappearance of the hydrocarbons. The work in this field has often been the subject of much research work in recent years. In this paper, the thermodynamics of CH4-CaSO4 and H2S-Fe2O3 systems is discussed to investigate the possibility of reactions. It is found that these two reactions can proceed spontaneously.Increasing temperature is favorite for CH4-CaSO4 system but disfavorite for H2S-Fe2O3 system. Thermal simulation experiments were carried out using autoclave at high temperature and high pressure. The properties of the products were characterized by microcoulometry, FT-IR and XRD methods. On the basis of the experimental data, a reaction kinetic model is developed and kinetic parameters are determined.     

高浓度H2O-NH3-CO2体系汽液平衡计算

A vapor liquid equilibrium model and its related interactive energy parameters based on UNIQUAC model for the H2O-NH3-CO2 system without solid phase at the conditions of temperature from 30℃ to 90℃, pressure from 0.1 MPa to 0.4MPa, and the maximum NH3 mass fraction up to 0.4 are provided. This model agrees with experimental data well (average relative error < 1%) and is useful for analysis of industrial urea production.     

Modeling and simulation of non-isothermal catalytic packed bed membrane reactor for H2S decomposition

The recovery of H₂ from H₂S is an economical alternative to the Claus process in petroleum and minerals processing industries. Previous studies [React. Kinet. Catal. Lett. 62 (1997) 55; Catal. Lett. 37 (1996) 167] have demonstrated that catalytic decomposition of H₂S over bimetallic sulfide can proceed at relatively higher rates than over mono-metallic systems due to chemical synergism although conversions are still thermodynamically limited. In the present study, the performance of a catalytic membrane reactor containing a packed bed of Ru–Mo sulfide catalyst has been investigated with a view to improving H₂ yield beyond the equilibrium ceiling. A system of differential equations describing the non-isothermal reactor model has been solved to examine the effect of important hydrodynamic and transport properties on conversion. The results were obtained using a Pt-coated Nb membrane tube as the catalytic reactor enclosed in a quartz shell cylinder. Reynolds number for shell and tube side (Re^s and Re^t) as well as the modified wall Peclet number, Pe_m, dramatically affect H₂S conversions. Membrane reactor conversion rose monotonically with axial distance exceeding the equilibrium conversion by as much as eight times under some conditions.     

氢氧质子交换膜燃料电池阴极流道设计模型

为了优化氢氧质子交换膜燃料电池阴极的气体流道,建立了沿流道长度和深度方向的气体流道设计模型.模型考虑了阴极气体在流道中的动量传递、质量传递和电极反应等物理过程.将二维问题经积分均化后转化为较简单的一维问题,偏微分方程组转变为常微分方程组,使计算过程得以简化.以50 cm长的流道为例,计算了沿流道方向的浓度、流速以及电流密度的分布.还利用此模型分析了各操作与设计参数如入口流速、流道深度、交换电流密度等对浓度、流速和电流密度分布的影响.     

Partial oxidation of ethanol on Ru/Y2O3 and Pd/Y2O3 catalysts for hydrogen production

The partial oxidation of ethanol was investigated over Ru and Pd catalysts supported onto yttria over a wide range of temperatures (473–1073 K). The product distributions obtained over these catalytic systems were correlated with diffuse reflectance infrared spectroscopy analyses (DRIFTS). Results showed that reaction route depended strongly on the type of metal. The decomposition of ethoxy species to CH₄ and CO or oxidation to CO₂ was promoted by Pd, and the acetaldehyde desorption was predominant over Ru in the low temperature region. Furthermore, the acetate and carbonate formation prevailed over Pd, which explained the lower acetaldehyde selectivity. The presence of CH₄ and CO₂ at high temperature is assigned to the decomposition of acetate species via carbonates over Pd-based catalysts. Ru was more suitable system for H₂ production than Pd by achieving a selectivity of about 59%.     

微波/过氧化氢协同降解苯酚动力学

研究了微波/过氧化氢（MW/H₂O₂）系统催化氧化降解苯酚的动力学。结果表明,在单独的微波辐射（MW）或者过氧化氢（H₂O₂）氧化条件下苯酚去除率很小,而在MW/H₂O₂系统中有显著的提高,表明协同效应存在。另外,在三种工艺条件下苯酚的降解均符合表观一级动力学。在MW/H₂O₂系统中苯酚去除的速率常数增强因子可达到5.98,根据此系统中存在MW、H₂O₂和羟基自由基（·OH）三部分协同作用的降解机理,推导出了简化的苯酚降解动力学模型,较好的反应过氧化氢浓度过量条件下的苯酚降解。     

H2, CO, N2, O2和CH4在碳膜中的扩散

Diffusion of pure H2, CO, N2,O2 and CH4 gases through nanoporous carbon membrane is investigated by carrying out non-equilibrium molecular dynamics （NEMD） simulations. The flux, transport diffusivity and activation energy for the pure gases diffusing through carbon membranes with various pore widths were investigated. The simulation results reveal that transport diffusivity increases with temperature and pore width, and its values have a magnitude of 10^-7 m^2·s^-1 for pore widths of about 0.80 to 1.21 nm at 273 to 300 K. The activation energies for the gases diffusion through the membrane with various pore widths are about 1-5 kJ·mol^-1, The results of transport diffusivities are comparable with that of Rao and Sircar （J. Membr. Sci., 1996）, indicating the NEMD simulation method is a good tool for predicting the transport diffusivities for gases in porous materials, which is always difficult to be accurately measured by experiments.     

Catalytic and electrocatalytic production of H2 from propane decomposition over Pt and Pd in a proton-conducting membrane-reactor

In the present study, the C₃H₈ decomposition reaction is studied in a double-chamber proton-conducting cell-reactor. The proton conductor was a strontia–ceria–ytterbia perovskite disk of the form: SrCe_0.95Yb_0.05O₃₋. The working electrode-catalyst was either Pt or Pd, in the form of a polycrystalline film. The reaction temperature varied between 923 and 1023 K and the partial pressure of propane in the feed gas was 2 kPa. The hydrogen produced by the reaction was electrochemically transported through the walls of the proton-conducting disk, to the outer reactor-chamber. The two electrodes (Pt and Pd) are compared in terms of their catalytic and electrocatalytic activities.