盐密、灰密对防污闪涂料憎水迁移性的影响

依据电力系统污区分布,通过静态接触角的测量度HC喷水分级法研究了涂层的厚度、盐密及灰密对涂层憎水迁移性的影响.结果表明:涂层的厚度、盐密对PRTV涂层的憎水迁移性影响较小,而涂层灰密对其憎水迁移性影响较大,灰密越大涂层的憎水迁移越困难.研究结果对涂层在污秽地区的运行具有指导意义,并为深入探讨灰密和盐密对防污闪涂料电气性能的影响提供理论依据.     

基于模糊综合评判的防污闪涂层状态评估方法

为全面反映防污闪涂层的运行状况,选取防污闪涂层特有外观特征量脱落、烧蚀、褪色、龟裂、粉化等,以宁夏电网样本为例,先对其涂层外面特征量进行打分,评定其等级,再使用基于模糊数学的模糊综合评判法进行计算,对防污闪涂层的状态进行判定。实例应用结果表明,最终评价结果反映了各个样品的老化程度,与宁夏电网实际情况相符,验证了所提方法的可行性。     

大型电站锅炉受热面电弧喷涂技术及应用

介绍了某电厂在锅炉大修时对受热面进行喷涂的情况。喷涂前针对材料的防腐蚀和防磨损性能进行试验,通过对比试验结果与技术规范,确定其现场可行性。由于喷涂材料较为昂贵,在进行喷涂面积计算时,需综合考虑经济效益和电厂受热面腐蚀磨损情况。通过喷涂前后效果对比分析表明:涂层对锅炉水冷壁换热无影响,具有良好的防腐、防磨特性。     

高温纳米陶瓷涂层在垃圾焚烧炉上的应用

为解决垃圾焚烧炉受热面发生的高温酸腐蚀、冲蚀磨损与沾污结渣等共性问题,提出采用喷涂高温纳米陶瓷材料进行防腐、防磨、防结渣处理。阐述了高温纳米陶瓷表面材料的性能指标和技术特点,以及喷涂施工工艺。该涂层在某垃圾焚烧炉中,经8 000 h现场服役后,涂层表面完好,检测结果表明该纳米陶瓷涂层对垃圾焚烧炉受热面具有优异的耐腐、抗磨和防结渣的作用。     

循环流化床锅炉管防磨喷涂

本文对循环流化床锅炉燃烧室卫燃带上部锅炉管采用火焰喷涂防磨层与采用超音速电弧喷涂复合涂层的使用效果进行了对比 ,提出了采用超音速电弧喷涂复合防磨涂层是解决循环流化床锅炉磨损问题的有效途径。     

制备新型高温受热面防磨涂层的实验研究

采用超音速电弧喷涂技术,在锅炉受热面常用钢材T91钢表面制备出耐磨损的复合涂层。对制备的耐磨涂层进行了涂层结合强度实验、XRD分析和涂层高温冲蚀实验,实验结果表明:采用超音速电弧喷涂技术制备出的耐磨涂层,不仅具有较高的耐磨性而且具有优异的抗高温冲蚀性能,适用于锅炉高温受热面的防护。为锅炉设备的受热面采用防磨涂层提供了理论依据。     

电气设备的污闪原因及防污闪节能措施

介绍了电气设备污闪的原因、条件及过程。针对严重污染进行的电磁设备防污闪措施分析 ,总结总降防污闪经验、节约能耗。     

高海拔地区750kV输变电设备外绝缘选取方法及绝缘子选型研究

根据750kV输变电示范工程的需求,对工程可能选取的4种大吨位电瓷绝缘子、4种大吨位玻璃绝缘子和3种不同伞裙结构的高强度、大直径电站支持绝缘子进行了不同海拔高度、多种污秽程度的试验研究;试验研究了硅橡胶复合绝缘子在不同海拔高度的污闪特性;比较了有、无RTV涂层的电站支持绝缘子污闪特性的差别。利用爬电比距法和污耐压法选取了不同污区、不同海拔高度的线路悬式和电站支持绝缘子的外绝缘尺寸,推荐了三层伞和双层伞型线路绝缘子为优选伞型。研究表明硅橡胶复合绝缘子比电瓷和玻璃绝缘子的耐污闪能力优异,建议在高海拔重污区首选复合型绝缘子。     

高海拔地区750 kV输变电设备外绝缘选取方法及绝缘子选型研究

根据750 kV输变电示范工程的需求,对工程可能选取的4种大吨位电瓷绝缘子、4种大吨位玻璃绝缘子和3种不同伞裙结构的高强度、大直径电站支持绝缘子进行了不同海拔高度、多种污秽程度的试验研究;试验研究了硅橡胶复合绝缘子在不同海拔高度的污闪特性;比较了有、无RTV涂层的电站支持绝缘子污闪特性的差别.利用爬电比距法和污耐压法选取了不同污区、不同海拔高度的线路悬式和电站支持绝缘子的外绝缘尺寸,推荐了三层伞和双层伞型线路绝缘子为优选伞型.研究表明硅橡胶复合绝缘子比电瓷和玻璃绝缘子的耐污闪能力优异,建议在高海拔重污区首选复合型绝缘子.     

油田污水回注井下综合防腐技术应用

介绍了回注污水腐蚀井下油套管的作用机理,确定了内涂层防腐油管 机械卡封隔离防腐(或化学软密封隔离防腐)工艺的综合防腐措施。通过氢渗试验确定最佳的内涂层防腐油管为热固化环氧粉末喷涂油管,介绍了机械卡封隔离防腐工艺、化学软密封隔离防腐工艺的原理、特点、技术要求等。利用综合防腐技术进行了现场应用,效果良好。     

转炉高温烟气除尘文氏管喷淋降温流动与传热性能分析

文氏管内部的流动与传热较为复杂,不仅涉及喷淋液滴与烟气在流动过程中的相互作用,而且涉及喷淋液滴遇到高温烟气发生相变进行的传热传质。视烟气为连续相,喷射液滴为离散相,考虑连续相与离散相在质量、动量和能量的相互作用,建立了转炉烟气文氏管喷淋降温三维瞬态数学模型。通过数值模拟,获得了文氏管内部压力、温度、速度和水蒸气摩尔分数分布,得到了不同烟气量、不同喷射水量条件下,文氏管压力损失和出口温度与挡板开度之间的关系。     

Performance of a direct formic acid fuel cell fabricated by ultrasonic spraying

The performances of a direct formic acid fuel cells (DFAFCs) comprising anode catalyst layers prepared via the following three different coating techniques are tested: direct paint (DP), ultrasonic spraying on the diffusion layer (US-D), and ultrasonic spraying directly on the membrane (US-M). These tests confirm that the ultrasonic spraying is a suitable method for the fabricating DFAFC anodes. Palladium black was used for the anode catalyst and a commercially available Pt/C cathode electrode was used for all tests. Scanning electron microscopy (SEM) revealed deep cracks caused by the porous substrate in the catalyst layers prepared by DP and by ultrasonic spraying on the diffusion layer. However, catalyst layers prepared by ultrasonic spraying directly on the membrane were less cracked and less porous, with small Pd particles. The catalyst layer prepared by ultrasonic spraying directly on the membrane showed the highest electrochemical surface area (ECSA) among the three anodes. In performance tests, ultrasonic spraying on the membrane yielded the highest power output because it produces the lowest ohmic resistance, the lowest anode potential, and the highest ECSA. By coating the catalyst membrane directly with ultrasonic spraying, we prepared a DFAFC with maximum power density as high as 245 mW cm^?2 using 5 M formic acid with 2 mg cm^?2 of catalyst loading.     

彩涂固化炉使用中需注意的几个问题

固化炉作为使涂料固化成膜的设备,是彩涂生产线的关键设备之一,它的正常运行与否对彩涂生产的质量、成本等有着重要的影响.在固化炉使用过程中,通过调节热风补充量、合理设置冷却系统各阀门开度和控制烧嘴火焰长度等方法,可以提高固化炉的热量利用率,降低煤气消耗,防止固化炉风箱变形,为彩涂生产线的稳定运行提供保障.     

The influence of paint dispersion parameters on the spectral selectivity of black-pigmented coatings

The optical properties of variously prepared black-pigmented solar absorbing paints were calculated in terms of their effective absorption and scattering abilities. The phenomenological two-parameter Kubelka–Munk effective medium theory was applied. Paints with the same composition were prepared for different degrees of pigment dispersion and characterized by the average size of pigment agglomerates present in the pigment/vehicle system. Prepared paints were applied to aluminum foil in two ways, by coil coating and by spraying. The size of coarse pigment particles and the paint application technique influence the spectral selectivity and thus determine the final performance of spectrally selective surfaces.     

Thermal Stress in Fabrication of Thermal Barrier Coatings

Thermal stress in the fabrication process of thermal barrier coating system (TBCs) has a significant effect on the quality of TBCs and the durability of gas turbine. In this work, a new analytical model was developed to calculate the thermal stress during the fabrication process of TBCs. Variations of the material properties with temperature of TBCs were well considered in the present model. Several spraying factors: such as pre-heating temperature, cold gas dynamic spraying (CGDS) method, thickness of top coating and thickness of substrate, which has significant effects on thermal stress generation, are also discussed in this work.     

Division Director's Message

It is believed that room temperature vulcanizing (RTV) silicon rubber coating is not passive but reacts to its environment. The hydrophobicity of the coating is extremely resilient and can recover under all exposure conditions provided there is adequate rest after removal of the stress (voltage, pollution, UV, etc). The present letter deals with the recovery characteristics of the hydrophobicity of the RTV-coated insulator during a combined continuous voltage and a cyclic low conductive fog application.     

Development of process for aluminising nickel alloy 718 strips for tube bundle support structures in liquid sodium–water steam generators

Abstract

The tubes in liquid sodium–water steam generators of the Indian prototype fast breeder reactor (PFBR) will be supported by corrugated nickel alloy 718 strips. Aluminisation of nickel alloy 718 strips has been chosen for this application because of the excellent performance of aluminide coatings in reducing impact fretting wear of the tubes due to flow induced vibrations and compatibility of the coating with liquid sodium at the operating temperature of the steam generators. Aluminisation of nickel alloy 718 strips for steam generator tube bundle support structures has been developed using a procedure involving thermal spraying of aluminium followed by diffusion heat treatment in vacuum atmosphere. One of the advantages of the technique is that it will coat only the desired surfaces of the strips, whereas in conventional pack cementation process, significant precautions have to be ensured. Furthermore, this process has enabled aluminisation to be carried out at a much lower cost than the conventional process of pack aluminising. The problems encountered during the initial trials and technology development, such as coating thickness and distortion, are discussed. A process flow chart for this procedure to take the job on an industrial scale is also reported. This process (under patenting) has been adopted for the aluminisation of corrugated strips for the support structures of one steam generator module and the steam generator for a test facility during the technology development phase, as also of all the steam generators being fabricated for the PFBR.     

耐磨损防护用FeCrMoCBSi系非晶涂层的性能研究

设计了5种不同硅硼含量的FeCrMoCBSi系粉芯线材,利用电弧喷涂技术制备涂层,对涂层的相组成、非晶相含量、非晶相稳定性、微观组织结构及涂层截面的显微硬度进行了研究和分析,测试了涂层在500℃时的耐磨粒磨损性能。结果表明:硅硼含量的调整使得涂层中的非晶相含量在47%到65.1%之间变动,却未引起涂层晶化温度的变化。随着涂层中非晶相含量的增加,涂层的显微硬度和耐磨粒磨损性能随之提高。其中,6%原子分数的硅元素和12%原子分数硼元素的添加的涂层中的非晶相含量最高,为65.1%,其晶化温度为853K,截面显微硬度平均值为1 302.1HV0.1,测试10h的相对耐磨性为GCr15轴承钢球的5.2倍。     

Finite element modeling of coating formation and transient heat transfer in the electric arc spray process

The electric arc sprayed coating can be described as a superposition of Gaussian profile particles whose overlapping depends on the movement of spray gun. The heat transfer behavior during the deposition has a significant influence on the performance of the process. In this paper, simulation of the coating formation and analysis of the transient heat transfer were performed based on a newly developed finite element model, in which the dynamic stochastic multiple particles deposition characteristic of the process was taken into account. In order to investigate the effects of the kinematics and dimensional aspects on the coating/substrate temperature distribution, a traditional layer-by-layer finite element model without consideration of gun movement and particles Gaussian profile was also performed as a comparison. The stochastic deposition model provided a more objective result of the transient heat transfer of the coating/substrate than that of the layer-by-layer model, especially the severely inhomogeneous temperature distribution characteristics in different locations and spraying conditions. Finally, the molding results were experimentally compared with the temperature measurements on the coating surface and substrate back face using an infrared thermal imaging video camera, which shows that most of the modeling findings are consistent with that of the experiment.     

微油枪喷射过程的数值模拟研究

微油点火系统中柴油的雾化燃烧过程是微油点火过程中的关键技术之一,针对微油枪的柴油喷射雾化过程开展细致的研究是电厂降低成本、节能减排的必经之路。文中针对微油枪油气混合喷射过程建立了计算数学模型,以0#柴油为基础,对微油枪喷嘴的喷射雾化过程进行了计算模拟分析,研究了不同空气进气量、不同柴油喷射温度,不同喷嘴结构对燃油喷射雾化的影响。