硫化氢制酸的生产技术进展

根据近年的文献报道，评述了硫化氢制酸的生产技术近况。内容包括硫化氢制成硫磺然后再生产硫酸，以及以硫化氢为原料直接制得硫酸。主要从工艺过程、二氧化硫回收率及产品硫酸的浓度等方面加以归纳和概述。通过比较分析得出，湿气制酸（WAX）工艺无论从工艺生产流程，还是二氧化硫转化率、能耗、操作费用和余热回收率等方面都有其独到之处，值得借鉴和引进推广。     

Effect of temperature on activity and selectivity of carbon supported Mo sulfide in simultaneous hydrodenitrogenation of pyridine and hydrodesulfurization of thiophene

Activity and selectivity of carbon supported Mo catalyst was tested in parallel hydrodenitrogenation (HDN) of pyridine and hydrodesulfurization (HDS) of thiophene in the temperature range 260–350 °C at 2 MPa of hydrogen pressure and compared with that of commercial NiMo-alumina catalyst Shell 324. The main advantages of carbon supported Mo sulfide over commercial NiMo catalyst can be summarized as follows: the markedly higher HDN and better HDS activities normalized to moles of active metals, the lower content of piperidine in the reaction products and the distinctly better selectivity towards HDN reaction.     

A study on structure and electrochemical properties of (La, Ce, Pr, Nd)2MgNi9 hydrogen storage electrode alloys

(La, Ce, Pr, Nd)₂MgNi₉ hydrogen storage alloys were prepared through induction melting followed by a long annealing treatment. The structure and electrochemical properties of annealed alloys have been investigated by orthogonal design experiments. Both the individual effects of each substituting element and their interaction in alloys were studied systemically. It has been shown that the structure of main phase in alloys belongs to PuNi₃-type with a space group R-3m. Substituting rare-earth elements have a significant effect on both the phase structure of alloys and microstructure. The anisotropic change in the crystal structure of alloys can cause the acceleration of pulverization of alloy particles and result in the deterioration of the cyclic stability of alloy electrodes. Misch metals can raise the plateau pressure of hydrogen absorption/desorption. The discharge capacity of alloy ranges from 342.97 to 380.68 mAh g⁻¹ depending on the sort and content of substituting elements. Both cerium and neodymium can obviously reduce the discharge capacity of alloy electrodes. When compared to the La₂MgNi₉ alloy electrode, mish metals can significantly improve the high rate dischargeability of alloy electrodes. The improvement of the kinetic characteristic of alloy electrodes mainly results from the increase of the hydrogen diffusion rate in alloy bulk.     

A paraffin-fueled SOFC system design and integration

This paper addresses an integrated design of paraffin-reformer, gas separations and the electricity production with a solid oxide fuel cell (SOFC). The overall design consists of three modules. First module is a system of paraffin reformer. In this module, the paraffin feed stream is to send to a steam-reformer. In the second module, the gas separations method illustrated is the combination of a methane-permeable membrane with a pressure-swing adsorption (PSA). In the third module, the purified hydrogen is fed to the SOFC unit. To be energy efficient, this paraffin-fueled SOFC system is designed with the consideration of heat integration. The intent of this paper is to provide a possible, alternative way of cogeneration systems for refinery and petrochemical plants.     

O3/H2O2 Treatment of Methyl-terf-Butyl Ether in Contaminated Waters: Effect of Background COD on the O3-Dose

The destruction of methyl-tert-butyl ether (MTBE) in contaminated waters by O₃/H₂0₂ process was studied and the influence background COD, alkalinity, and hydrogen peroxide and MTBE concentrations on process treatment efficiency and ozone dosage was investigated. The treatment efficiency was evaluated by an Efficiency Index, which is based on electrical energy requirement for ozone production. It was found that the treatment efficiency decreases linearly with increasing concentrations of MTBE at constant background COD and with background COD at constant MTBE concentration. A simplified kinetic scheme was presented to account for these observations.     

Reforming of methane with carbon dioxide over supported bimetallic catalysts containing Ni and noble metal: I. Characterization and activity of SiO2 supported Ni–Rh catalysts

Cobalt catalysts supported on silica aerogel have been prepared using sol–gel chemistry followed by drying under supercritical ethanol conditions. Three different loadings of cobalt were synthesized: 2, 6, and 10% by weight. Transmission electron micrographs indicate that the metallic cobalt exists as discrete particles 50–70 nm in diameter for the 2 and 6% loadings. The 10% catalyst shows long needles of cobalt. BET and BJH measurements indicate that the catalysts retain the silica aerogel properties of high surface area (∼800 m²/g), large pore volume (∼5 cm³/g), and an average pore diameter in the mesoporous regime (∼25 nm). The catalysts were evaluated for Fischer–Tropsch activity in a laboratory-scale packed bed reactor. All three catalysts were active with the 10% Co catalyst achieving more than 20% CO conversion which corresponds to a rate of 1.53 g CO per g-cat per hour. The catalysts were selective for the C₁₀₊ hydrocarbons with more than 50% of the carbon contained within this fraction. A significant portion of the C₉–C₁₅ hydrocarbon product was observed as 1-olefins which reflects the enhanced mass transport within the very porous aerogel support.     

Thermoelectric hydrogen sensor using Li x Ni1-x O synthesized by molten salt method

Li-doped NiO was synthesized by molten salt method. LiN_O3-LiOH flux was used as a source for Li doping. NiCl₂ was added to the molten Li flux and then processed to make the Li-doped NiO material. Li:Ni ratios were maintained from 5: 1 to 30: 1 during the synthetic procedure and the chemical compositions after characterization were found from Li_0.08Ni_0.92O to Li_0.16Ni_0.84O. Li doping did not change the basic cubic structural characteristics of NiO as evidenced by XRD studies; however, the lattice parameter decreased from 0.41769 nm in pure NiO to 0.41271 nm in Li_0.16Ni_0.84O. Hydrogen gas sensors were fabricated by using these materials as thick films on alumina substrates. The half surface of each sensor was coated with the Pt catalyst. The sensor, when exposed to the hydrogen gas blended in air, heated up the catalytic surface leaving the rest half surface (without catalyst) cold. The thermoelectric voltage thus built up along the hot and cold surface of the Li-doped NiO made the basis for detecting hydrogen gas. The linearity of the voltage signal vs H₂ concentration was checked up to 4% of H₂ in air (as higher concentrations above 4.65% are explosive in air) using Li_0.10Ni_0.90O as the sensor material. The response time T₉₀ and the recovery time RT90 were less than 25 sec. H₂ concentration from 0.5% to 4% showed a good linearity against voltage. There was minimum interference of other gases and hence H₂ gas can easily be detected.     

纳米尺寸硫化镍化学增感剂

本文发现了硫化镍纳米粒子对卤化银乳剂的化学增感作用，采用水不溶性的硫化镍纳米粒子作为化学增感剂，与水溶性的硫代硫酸钠增感剂相比，可以在乳剂灰雾增加不大的条件下明显提高乳剂的感光度和反差。     

氯气干燥系统的技术改造

介绍了引起氯气干燥系统设备管道漏裂、堵塞、腐蚀的原因及其危害性,提出了包括设定合理的工艺参数,严格执行操作规程及改造更新设备管路等解决措施。     

Na2S-SO2反应体系中H2S产生的过饱和态分析

向Na2S溶液中通入低浓度SO2气体以生成H2S，H2S从液相中逸出时，存在一突跃现象。本文根据这一现象，结合Y．T．Shah等提出的吸收－反应－解吸体系中过饱和态存在的条件，通过理论分析，得出在Na2S-SO2-H2S4反应体系中H2S解吸存在过饱和现象。