Oxygen barrier coating deposited by novel plasma‐enhanced chemical vapor deposition

We report the use of a novel plasma‐enhanced chemical vapor deposition chamber with coaxial electrode geometry for the SiO_x deposition. This novel plasma setup exploits the diffusion of electrons through the inner most electrode to the interior samples space as the major energy source. This configuration enables a gentle treatment of sensitive materials like low‐density polyethylene foils and biodegradable materials. SiO_x coatings deposited in the novel setup were compared with other state of the art plasma coatings and were found to possess equally good or better barrier properties. The barrier effect of single‐layer coatings deposited under different reaction conditions was studied. The coating thickness and the carbon content in the coatings were found to be the critical parameters for the barrier property. The novel barrier coating was applied on different polymeric materials, and it increased the barrier property of the modified low‐density polyethylene, polyethylene terephthalate, and polylactide by 96.48%, 99.69%, and 99.25%, respectively. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

The Chatham demonstration: From design to operation of a 20 m/d membrane-based ethanol dewatering system

Distillation/dehydration represents the largest fraction of the energy used in the production of ethanol. The Siftek™ technology introduced in this paper carries the potential of reducing energy consumption of distillation/dehydration by up to 50% through the single pass removal of water from the water/ethanol stream at the beer column outlet, using a novel membrane process.Siftek™ is a polymeric membrane that can be used to dry ethanol in the vapor phase. The membrane preferentially permeates water over ethanol in a continuous process. Energy reductions are obtained because this membrane is well suited to remove large quantities of water without phase change.The Siftek™ technology has been piloted since August 2006 in a Greenfield Ethanol plant in Tiverton, Ontario, Canada. The Tiverton unit has a capacity of 1 m³/d and has been producing fuel ethanol from a feed containing between 75 and 90 wt.% ethanol in a single stage system.Based on the successful operation of the pilot, it was decided to scale-up the technology. A two-stage membrane system with a capacity of 20 m³/d was built for the Greenfield Ethanol plant in Chatham, Ontario, Canada. The unit is equipped with full-scale commercial membrane modules and is capable of treating a beer-column feed containing 60-70 wt.% ethanol, producing > 99 wt.% fuel-grade ethanol.     

化学镀镍层起泡脱皮原因分析及解决方法

化学镀镍层起泡脱皮会导致无镀层部位的加速腐蚀,在表面处理中是不允许出现的.因此,分析化学镀镍层起泡脱皮原因,找出其解决办法.通过试验得出结论:化学镀镍层有渗氢现象,原子态氢集聚形成气泡.减少施镀时间,降低镀层厚度,解决了镀层起泡脱皮质量问题,保证了化学镀镍零件的防腐性能.     

Carbon dioxide reforming of methane in a SrCe0.7Zr0.2Eu0.1O3−δ proton conducting membrane reactor

Utilizing CO₂ for fuel production holds the promise for reduced carbon energy cycles. In this paper we demonstrate a membrane reactor, integrating catalytic CO₂ reforming of methane with in-situ H₂ separation, that results in increased CO₂ and CH₄ conversion and H₂ production compared to a Ni catalyst alone. The tubular proton-conducting SrCe_0.7Zr_0.2Eu_0.1O_3−δ membrane reactor demonstrates that the addition of the membrane improves CO₂ conversion, due to in-situ H₂ removal, by 10% and 30% at 900 °C for CH₄/CO₂ = 1/1 and CH₄/CO₂/H₂O = 2/1/1 feed ratios, respectively. It also improves total H₂ production at 900 °C by 15% and 18% for CH₄/CO₂ = 1/1 and CH₄/CO₂/H₂O = 2/1/1, respectively. Further, the H₂/CO in the reactor side effluent can be adjusted for subsequent desired Fischer-Tropsch products by combining CO₂ reforming and steam reforming of methane.     

Preparation Methods and Properties of PdCu Alloy Membrane for Hydrogen Transition

Pd and Pd alloy membranes are of increasing interest for hydrogen separation and purification due to their good thermal stability, high permeability and perfect selectivity. PdCu alloy (60wt% Pd) membranes have similar hydrogen permeability compared with PdAg alloy; meanwhile, it is cheaper than PdAg alloy. Furthermore, it has been reported that PdCu membrane has better resistance to poisoning and deactivation by H 2 S impurity. This paper reviews the properties and manufacturing methods of PdCu alloy membrane, finally, introduced some achievement made by us on PdCu alloy membrane.     

Welding heat input effect on the hydrogen permeation in the X80 steel welded joints

In this study, the effect of microstructure at the base metal (BM), the fine grain heat affected zone (FGHAZ), the coarse grain HAZ (CGHAZ) and weld metal (WM) under different welding heat input on hydrogen permeation in X80 steel weldments have been investigated. Base metal showed the highest effective diffusivity. With each heat input, the effective hydrogen diffusivity in FGHAZ is comparable to that of the base metal. The effective hydrogen diffusivity in weld metal was lower than that in CGHAZ. With increasing the welding heat input, the effective diffusivity in different zones of the weldment decreased correspondingly. Non-metallic inclusions were not detected in each specimen. Constituents in microstructure under low heat input are likely to agglomerate during accelerated cooling. The retained hydrogen may create an unpredictable susceptibility to hydrogen cracking at the CGHAZ even existing during service.     

Novel styrene polymers functionalized with phosphorus–nitrogen containing molecules: Synthesis and properties

A phosphorus and nitrogen-containing compound with high phosphorus content, AC₂NP₂, was firstly synthesized by the Kabachnik–Fields reaction and followed by esterification with acryloyl chloride. The synthesized comonomer was then incorporated into different amounts of polystyrene via radical solution polymerization. The copolymers were well characterized using Fourier transform infrared (FTIR), UV/vis spectrophotometer, nuclear magnetic resonance (NMR), gel permeation chromatography (GPC), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), microscale combustion calorimeter (MCC) and LOI. The results showed that the AC₂NP₂ was easily incorporated into the backbone of polystyrene, and the copolymers prepared have high transparency. The glass transition temperature (T_g) of the copolymers was decreased with increasing the AC₂NP₂ content, due to the introduction of much more flexible molecular chain. The TGA results revealed that the introduction of AC₂NP₂ units slightly decreased the initial decomposition temperatures, but significantly improved the thermal stability of copolymers at high temperature regions under both nitrogen and air atmosphere. Furthermore, all the copolymers exhibited much lower flammability as compared with virgin polystyrene.     

隔膜泵在低产油田集输工程中的应用

陕甘宁地区地形复杂,小产量油井多,井位分散。用DY型多级离心泵无法解决长距离集输的管堵、井口压力高等问题。采用改进的JM系列高压液压隔膜式计量泵能够解决低产油井在地形复杂情况下长距离输油问题。分析了低产、低渗油田和气田采用JM系列隔膜泵的结构区别和在低产油田的应用特点。     

高密度聚乙烯管材专用树脂的双检测器凝胶色谱测定

建立了一种采用示差折光计-自动黏度计双检测器凝胶色谱测定高密度聚乙烯(HDPE)管材专用树脂相对分子质量(M)及其分布的方法,并对仪器的稳定性和方法的精密度进行了考察。结果表明,该方法无须借助聚合物的K和α值,便可直接测定HDPE管材专用树脂"真实"的M及其分布。方法精密度高,具有较强的实用性。     

Some physical properties of acetosolv lignins from bagasse

Acetosolv-solubilized lignins were characterized by their solubility in different organic solvents, Fourier transform infrared, ¹³C-NMR, UV, gel permeation chromatography, differential scanning calorimetry, and thermogravimetric analysis. Solvents having a solubility parameter in the range of 10–12.7 and a hydrogen-bonding parameter in the range of 3.6–5 were considered good solvents for acetosolv lignins. Fourier transform infrared spectra of the lignins were typical for lignins containing p-hydroxy phenylpropane (H), guaiacyl (G), and syringyl (S) units. The lignins contained more conjugated and fewer nonconjugated CO groups, and the guaiacyl groups were etherified and condensed. ¹³C-NMR confirmed partial acetylation of the lignins and the presence of β-O-4 and β-5 linkages. Acetosolv lignins also showed the typical UV spectrum of annual plants. The effects of the acetic acid concentration and pulping time on the molecular weights of the lignins were explained with the presieving and condensation concepts. The thermal behavior of the acetosolv lignins was also studied. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008