电除尘器绝缘子的设计与选择

根据电除尘器绝缘子的功能、工况条件等特点，分别从材质、外形尺寸等方面介绍了设计和选择的注意事项。为用户合理地选择电除尘器绝缘子提供了帮助。     

如何克服电除尘器绝缘子的热击穿和绝缘老化

电除尘器绝缘子一般都是在一定温度的高压电场中工作,在电场和温度场的复合作用下,绝缘子的热击穿和绝缘老化是造成其绝缘失效的主要形式。在以固体电介质为中心的绝缘组合中,当受电场和温度场复合作用注入的能量大于散热量时,绝缘子本体温度上升直至发生击穿。电除尘器绝缘子的热击穿不仅取决于电场强度,还与周围的环境温度和材料本身的特征有关。通过研究绝缘材料在高温下的电学性能,尽量选择t_e值(当材料电阻率下降至1 MΩ·cm时的温度)较高的材料制造电除尘器绝缘子,优化绝缘配合的设计,设法均匀绝缘子周围的电场,可有效地阻止热击穿和延缓绝缘老化,提高电除尘器绝缘子的适应性和可靠性,以满足电除尘器高温、高压电场的特殊绝缘要求。     

刚玉陶瓷拉棒在电除尘器中的应用

电除尘器中的阴极吊挂是电除尘器的核心部件,它对阳极(本体)之间的电位差,一般在72kV以上,有些企业为了提高收尘效果,将电压提高到了120kV,其重量根据整机规格大小,从几百公斤到几十吨不等。要将其可靠地固定在电除尘器的本体框架内,只能靠瓷绝缘子来承担。瓷绝缘子能否受此重任,须看其材质性能。笔者对刚玉陶瓷拉棒在电除尘器中的应用做了较深入的研究,总结成文,以供参考。     

复合绝缘子雷击闪络事故的原因

长沙理工大学的敬亮兵等人通过对福建某山区110kV输电线路复合绝缘子的雷击闪络事故进行分析,总结出复合绝缘子遭雷击闪络的主要原因是干弧距离太短、均压环单端配置以及接地电阻超标。提出了在山区雷电多发地段防雷击闪络的措施：使用加长型合成绝缘子、安装双均压环以及降低杆塔接地电阻。实践证明,这些措施对防止复合绝缘子的雷击闪络起到了很好作用。     

陶瓷绝缘材料高温电阻的测量

由于电除尘器用陶瓷绝缘子在高温环境下运行,在生产和验收过程中必须对其高温电阻进行控制和检测。介绍了陶瓷绝缘材料高温电阻的测量方法、电化时间、升温方式和测量操作,探讨了试样选择及处理、电极选择、温度控制,指出应根据不同测量目的采用不同的测量方法,尽量克服测量误差,提高精确度。     

水泥污秽对复合绝缘子闪络特性的影响

青海电力科学试验研究院的李志玮等人以水泥和氯化钠为污秽,研究了氯化钠污秽（盐密）一定的情况下,水泥污秽（灰密）对复合绝缘子污秽闪络特性的影响。结果发现,灰密对绝缘子人工污秽闪络电压有影响,闪络电压与灰密成幂函数关系,且灰密与闪络电压的影响是独立的。     

高压绝缘子泄漏电流在线监测技术

污闪事故是威胁电力系统安全运行的灾难性事故之一,通过对绝缘子污秽闪络的分析,比较了泄漏电流法和其他方法的区别,并对高压输电线路上的绝缘子引出了数学模型和测量方法,同时也对泄漏电流在线监测系统做了简要的介绍。     

95氧化铝瓷绝缘子瓷转轴在侧部振打电除尘器上的应用

研究了侧部振打用９５氧化铝瓷绝缘子瓷转釉,并简要介绍了其制造工艺,对比分析了电瓷材料与９５氧化铝陶瓷材料的性能差异。指出９５氧化铝瓷是电除尘器行业用绝缘子的最佳陶瓷材料。     

95氧化铝瓷绝缘子瓷转轴在侧部振打电除尘器上的应用

研究了侧部振打用95氧化铝瓷绝缘子瓷转釉 ,并简要介绍了其制造工艺 ,对比分析了电瓷材料与95氧化铝陶瓷材料的性能差异。指出95氧化铝瓷是电除尘器行业用绝缘子的最佳陶瓷材料。     

高箱体袋除尘器在“电改袋”方案中的应用

国家环保要求的不断提高、袋除尘技术的进步、水泥生产工艺技术的改变使电除尘器的应用面临着巨大的挑战。高箱体袋除尘器结构充分利用了原电除尘器的壳体空间,顶部采用大的封闭披屋结构,出气空间大,气流顺畅,设备阻力低。鹿泉东方鼎新水泥公司窑尾电改袋的案例说明高箱体袋除尘器应用的可靠性。     

焚硫炉设计的改进

总结焚硫炉使用中出现的问题，对焚硫炉结构的设计和选材进行了改进和完善。针对保温材料选用不合格致使焚硫炉壳体温度过高，调整炉墙 厚度，保温层同耐火层一样设为114mm和230mm两层。随着硫磺制酸不断大，粘土质耐火砖的高温机械性能达到极限，建议焚硫炉内层迎火面、挡墙选用高铝砖砌筑，次内层仍用粘土砖，以保证焚硫炉稳定操作。以砂改用槽钢代替角钢加强，并缩短槽钢间距，增加预留膨胀缝量，解决封头的变形。     

火花塞瓷件黑釉的研制

本文根据火花塞瓷件95氧化铝瓷的特性要求,对黑釉的配方及上釉工艺进行了研究。在满足火花塞技术要求前提下,瓷件上黑釉,可以改善火花塞整体外观质量。结果表明:火花塞瓷件伞棱表面釉层纯黑发亮,釉面商标采用特制花纸烧成,装配成的火花塞精致美观。     

Improving surface quality of microcellular injection molded parts through mold surface temperature manipulation with thin film insulation

Microcellular injection molding offers many advantages such as material and energy savings, reduced cycle times, and excellent dimensional stability. However, typical surface characteristics of microcellular injection molded parts—such as gas flow and swirl marks and a lack of smoothness—have precluded the process from being used for applications where surface appearance is important. This article presents an insulator‐assisted method that has been shown to improve the surface quality of microcellular injection molded parts significantly. By incorporating a thin film (75–225 μm) of polytetrafluoroethylene (PTFE) insulator on the mold surface, the polymer melt–insulator interfacial temperature can be manipulated and can be kept high enough during mold filling to reduce or eliminate swirl marks on the surface. The experimental results in terms of surface roughness and surface profile of conventional and microcellular injection molded parts with and without the insulator film are discussed. Thermal analyses of the corresponding microcellular injection molding experiments were performed to elucidate the correlation between film thickness, interfacial temperature, and the surface quality. The effect of insulator on the cooling time increase is also analyzed and presented. POLYM. ENG. SCI., 2010. © 2010 Society of Plastics Engineers     

A Model‐Based Approach to Determine the Design Space of Preparative Chromatography

A dream of many pharmaceutical companies is to be able to register a large design space with the regulatory agencies. The problem is that this will require both time and money, so an intelligent method of validating a design space is needed. The design space should only cover operating points at which the process runs optimally. This means that the process should be optimized for different process scenarios and objective functions and the found operating points should be registered as design space. This paper presents a method of determining a good design space by creating Pareto fronts for the ideal case and for various process disturbance scenarios. Optimal operating points are found for varying ratios between feed costs and operating costs, making it possible to make a quantitative choice of an operating point based on this ratio and a qualitative choice based on the whole front. The analysis will show how the chromatographic process can be made more robust when optimizing for higher yields, and how the effect of the critical process parameters can change. To be certain that a robust process is found and that it has a high performance, process disturbances must be taken into account when optimizing a process.     

室温钠离子电池用高性能碳材料研究进展

随着大规模储能领域对性价比要求的日益提升,室温钠离子电池有望成为新一代能源存储器件。在多种备选材料中,出于综合性能、成本和安全性考虑,碳基材料是最具实用潜力的钠离子电池负极材料之一。值得注意的是,体相扩散型碳和表面吸附型碳在储钠位点、电化学行为和设计思路上有很大区别。综述了两类碳材料近年来的研究进展,探讨了储钠机理、电解液匹配以及关键性能提升等问题。最后,对钠离子电池碳基负极材料研究面临的挑战及未来发展方向进行了展望。     

Fast formation of a black inner α-Al2O3 layer doped with CuO on Al–Cu–Li alloy by soft sparking PEO process

Forming high-temperature α-Al₂O₃ phase under soft sparking is an intriguing phenomenon in plasma electrolytic oxidation (PEO) of Al alloys, which contradicts the low energy input of the process. In this study, α-Al₂O₃ doped with black CuO is formed beneath an amorphous white outer layer on Al–Cu–Li alloy by PEO in a dilute silicate electrolyte under soft sparking. In comparison, reddish coatings with dominating γ-Al₂O₃ are formed under the conventional plasma discharges, although blackish inner layer with α-Al₂O₃ can also be exposed by heavily polishing the samples. In order to know the underlying mechanism, temperatures at the coating surface and the underlying substrate have been monitored by a thermocouple under the conventional and soft sparking PEO regimes, respectively. Interestingly, high temperatures are detected in the case of soft sparking rather than PEO with strong discharges. The formation of CuO, quartz, and cristobalite within the soft sparking coating also supports the existence of high temperature. Hence, the formation of α-Al₂O₃ under soft sparking can be resolved to the conventional thermal activation mechanism, without the need of seeking other plausible explanations. Thermal condition evaluation for soft sparking PEO suggests that values of the effective thermal conductivity during PEO process for the outer layer and the barrier layer at the coating/substrate interface might be lower than ∼0.05 and ∼0.0017 W m⁻¹ K⁻¹, respectively. It is believed that the amorphous structure of the outer and barrier layers effectively blocks the heat dissipation, facilitating the formation of a highly wear-resistant inner layer with α-Al₂O₃, CuO, and the other high-temperature species under soft sparking.     

Crystal structure and ab initio calculations of CaZrO3

Calcium zirconate (CaZrO₃), because of its high melting point, low thermal expansion coefficient, high strength and excellent corrosion resistance against alkali oxides, is a good candidate for a novel refractory material. CaZrO₃ is mostly synthesized by the reaction in the solid state but the material obtained in such a way often suffers low bulk density, high porosity and other defects which lower its potential application value. To overcome these obstacles a novel synthesis method by an electric arc melting technique was proposed. The crystal structure of melted CaZrO₃ was compared with a conventionally synthesized material. According to X-ray measurements the obtained material has an orthorhombic perovskite-like structure. Its stoichiometry was confirmed by the scanning electron microscope and EDS analysis. The material is almost poreless with its density close to theoretical. The estimated crystal structure parameters were used to calculate the electronic structure of CaZrO₃ using the full potential linear augmented plane wave (FLAPW) method. It has been found that CaZrO₃ is an insulator with the energy band gap of 4.1 eV. The Ca-O bond is typically ionic while Zr-O bond is of a significant covalent character.     

有机热载体炉的安全使用

文章介绍了影响有机热载体炉安全使用的四个方面:有机热载体的选用原则是高热稳定性、环保性能和最高使用温度;有机热载体质量监测和控制的四个主要指标是运动粘度、闪点、残炭和酸值,应符合相应要求,以及防止有机热载体过热和氧化的方法;有机热载体炉的设计和安装应符合《有机热载体炉安全技术监察规程》要求;严格执行有机热载体炉的安全操作规程,预防事故发生。     

高梯度磁分离铬盐浸出浆液中的铬渣-Ⅰ.理论分析

提出了将铬渣从铬盐浸出浆液中去除的高梯度磁分离方法,建立了高梯度磁分离器的分离能力与设备参数、操作参数和物料性质参数之间关系的理论模型,定量讨论了磁场强度和操作温度对有效分离时间的影响.     

Morphological evolution of polytetrafluoroethylene in extreme temperature conditions for aerospace applications

The organic electrical insulator polytetrafluoroethylene (PTFE) is used in aerospace industry under extreme conditions of temperature and electric field. The melting temperature of PTFE is about 327°C and nowadays operating temperature of this kind of insulators can reach about 300°C and up to 350°C for new generations of machines. All thermal, electrical and mechanical operating stresses, especially high temperature and voltage can be factors of ageing acceleration and/or degradation of the insulators that could cause premature failures. Our present work is focused on the organic insulator behavior at high temperature in order to understand the mechanisms of thermal ageing and degradation. The change of morphology of PTFE during the thermal ageing has been studied. Thin films in PTFE were aged by accelerated method under oxidizing environment (air) and severe thermal constraints between 340 and 450°C. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 39841.