共查询到19条相似文献,搜索用时 250 毫秒
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为研究水冷壁管材料15 CrMo在含SO2-4溶液中的点蚀特性,通过常温电化学实验和高温挂片实验,对常温性能和高温腐蚀特性进行分析,用透反射金像显微镜、SEM、EDS、XRD对试片表面形态和组分进行表征与分析.结果表明:常温条件下,SO2-4主要以氧化作用为主,抑制不锈钢的腐蚀,材料的耐蚀性增加;高温条件下,SO2-4为侵蚀性离子,将加速材料的点蚀,形成带有锯齿状边缘的点蚀坑,其点蚀临界浓度为1mg/L;常温下SO2-4抑制Cl-点蚀的机理是竞争吸附,高温条件下SO2-4促进点蚀的机理为局部酸化理论. 相似文献
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漏入热力系统破碎阳树脂的高温分解是电站水汽系统SO24-含量超标的原因之一。针对这一问题,采用高压釜实验对几种凝结水精处理常用阳树脂的SO24-高温分解特性进行了研究。结果表明:阳树脂高温分解后其交换基团(—SO3H)会从树脂骨架上脱落并产生SO24-,其分解产生SO42-的量随分解温度的升高而增大,当温度超过200℃后会出现骤增现象,并产生大量酸性物质;旧树脂分解产生SO42-的量略小于新树脂,但会产生更多的酸性物质;在280℃条件下,阳树脂分解产生SO42-的量随时间的增加而增加,实测SO42-结果与红外光谱检测结果都表明某些树脂分解24 h后几乎达完全分解。 相似文献
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《锅炉技术》2020,(4)
模拟垃圾焚烧炉内环境,在550℃条件下,开展了T91、TP347H、TP347HFG、TP310S、UNS 6625等材料的腐蚀实验研究。采用减重法和壁厚法分别计算腐蚀速率,利用光学显微镜和配有能谱仪的扫描电镜对试样件腐蚀后的形貌结构、元素含量进行分析。结果表明:垃圾焚烧炉中积灰腐蚀严重,可采用改善受热面清洁状况及优化受热面材质的方法减轻;在相同条件下,镍基合金材料UNS 6625由于其氧化物在氯化物熔盐中的热稳定性好,腐蚀速率小,耐腐蚀性好,可用于垃圾焚烧炉中的高温部位;不锈钢材料表面的晶粒细化后,能有效改善材料的抗腐蚀性能;在工程现场,壁厚法仅适用于无晶间腐蚀的材料,不适用于不锈钢材料;不锈钢材料的腐蚀情况判断应将晶间腐蚀考虑在内,并结合SEM-EDS分析。 相似文献
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选取5种典型耐热材料T91、VM12、Super 304H、Inconel 617和Sanicro 25为实验材料,在600℃、15 MPa条件下进行超临界二氧化碳腐蚀实验.通过分析天平获得耐热材料增重量变化;利用拉曼光谱仪、X射线衍射仪和辉光放电光谱仪对耐热材料表面腐蚀产物进行物相和成分表征;利用电子显微镜进行表面和断面形貌观测,最后分析耐热材料的腐蚀行为.结果表明:T91和VM12符合抛物线型.腐蚀动力学规律,Super 304H、Inconel 617和Sanicro 25则增重量不明显,没有明显规律;增重量与耐热材料的Cr质量分数呈反比关系;在高温超临界二氧化碳环境中耐热材料发生了氧化和碳化反应;T91和VM12没有贫Cr现象,而Super 304H、Sanicro 25和Inconel 617则具有明显的贫Cr区域,且贫Cr区域厚度由小到大依次为:Inconel 617<Sanicro 25<Super 304H. 相似文献
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选取电站锅炉过热器材料T91钢为研究对象,利用高温管式炉探究在一定拉应力条件下SO_2对锅炉用钢高温腐蚀的影响.设定腐蚀温度分别为700℃和750℃,在试样经过168h的腐蚀实验后,对其进行X射线衍射(XRD)与扫描电子显微镜(SEM)分析.结果表明:腐蚀层一般分为内外2层,分别为Cr基氧化层和Fe基氧化层;在拉应力条件下,SO_2气相腐蚀不影响腐蚀厚度,但会影响内外腐蚀层的厚度比例及表层的晶粒大小;拉应力会促进Cr的迁移,但不会影响Ni的迁移过程,而且会减少Fe基氧化层中阴离子的缺陷,阻止S的内部迁移;SO_2气相腐蚀影响腐蚀层的脱落方式,会导致腐蚀层易整体脱落. 相似文献
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李丹 《中国锅炉压力容器安全》2010,(2):1-3,15
本文选用目前治理火电站受热面管道中常用的两种喷涂材料,结合高速电弧喷涂技术制备防腐涂层,利用扫描电镜、X—Ray衍射等试验手段对其腐蚀产物及腐蚀机理进行分析和探讨,为选材提供理论依据。研究结果表明,喷涂后形成的涂层具有典型的层状结构,较高的结合强度和硬度,涂层的耐高温冲蚀性能良好,同时常温和高温耐磨损性能也较高;适用于电站锅炉“四管”的防护。 相似文献
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基于某热电厂实际情况,分析该厂煤粉锅炉水冷壁高温腐蚀的机理、高温腐蚀的影响因素并探讨抑制措施。 相似文献
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采用人工加速腐蚀实验方法,研究了电站尾部烟气对烟囱混凝土的影响。对在H2SO4、HCl和HF酸液下的低温腐蚀进行了比较研究。结果表明:3种酸液对混凝土腐蚀的发展规律符合幂函数的变化关系;在H2SO4和HCl腐蚀下,抗压强度随腐蚀时间的延长而降低,但在HF酸中,抗压强度增加;抗压强度的变化值随着中性化深度增加而增加。混凝土中CaO含量下降是引起强度降低的主要原因;强度大幅度降低(HF酸除外)的根本原因,是由于混凝土中Ca(Al2Si2O8)·4H2O、Na6AlSi2O7和Ca2SiO4·4H2O等组分大量减少。 相似文献
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AbstractThe Supercontainer design is the preferred option for the underground disposal of high level nuclear waste in Belgium. It consists of a carbon steel overpack surrounded by a thick concrete buffer. In this high alkaline environment and under normal conditions (without the ingress of aggressive species), the carbon steel overpack will be protected by a passive oxide film, which is believed to result in very low uniform corrosion rates. The backbone of the RD&D strategy, which aims to provide confidence that the integrity of the overpack will be maintained at least during the thermal phase, is based on demonstrating that each localised corrosion mechanism (e.g. pitting corrosion, crevice corrosion and stress corrosion cracking), other than uniform corrosion, cannot take place under the high pH conditions prevailing within the Supercontainer (the ‘exclusion principle’). This paper gives an overview of the status of the RD&D programme related to the anaerobic uniform corrosion of the carbon steel overpack. The outcome of the modelling efforts simulating the evolution of various parameters (temperature, pH, degree of saturation, corrosion potential and composition of aggressive species) that can potentially influence the corrosion processes, over geological timescales, is addressed. 相似文献
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《International Journal of Hydrogen Energy》2022,47(54):23038-23059
The combustion and ignition characteristics of three fuels with different reactivities have been investigated by a reduced chemical kinetic model. In the present work, the chemical kinetics of conventional single fuel and binary fuel, relevant to gas-turbine engines, are extended and attempted to explore in the tri-fuel (TF) context, with the help of TF blends of LPG + CH4+H2 at the pressure and temperature range of 1–20 atm and 900–2000 K, respectively. The blending of hydrogen with hydrocarbon fuels improves flame propagation, reduces emissions, and increases the combustion performance of the engine. A detailed study is conducted to explore the characteristics of TF mixture over a wide range of operating conditions by considering eight different test mixtures (M1-M8). The test mixtures (M2 to M4) contain higher hydrogen content and thus hydrogen kinetics will tend to dominate, while test mixtures (M6 to M8) contain a higher concentration of hydrocarbons, thus the methyl radical chemistry plays a prominent role in the oxidation process. Such contrasting trends were further explored by extensive chemical kinetic modeling with the help of the reduced USC Mech_50 species model from our previous work [1] to analyze the ignition delay time, laminar flame speed, flame temperature, and heat release rate characteristics. In addition, the reaction pathway analysis through sensitivity analysis of OH and CO radical, and flow rate sensitivity analysis has also been conducted to highlight the essential chemical reactions which play a crucial role in auto-ignition, combustion, and emissions characteristics of TF blends. 相似文献
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在一座热输入功率为90 kW的鼓泡流化床焚烧试验装置上进行油页岩干馏废水焚烧试验,考察床温、过剩空气系数、一二次风比和Ca/S比对排烟中NOx和SO2浓度的影响.结果表明:由于废水中氨氮含量较高,焚烧时随着床温的升高,NOx的排放浓度呈现先下降后上升的趋势,而非广泛接受的单调上升的规律,SO2的排放浓度呈上升趋势;随着过量空气系数的升高,NOx的排放浓度呈先下降后上升的趋势,SO2的排放浓度呈下降趋势;随着二次风率的升高,NOx的排放浓度呈下降趋势,SO2的排放浓度呈上升趋势;随着Ca/S比的升高,NOx的排放浓度先上升后下降,SO2的排放浓度逐渐下降.本次试验各工况下NOx的排放浓度范围为104.2~257.9 mg/m3;SO2的排放浓度范围为36.7 ~179.8 mg/m3,均满足国家排放标准. 相似文献
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Donghai Xu Zhijiang Ma Shuwei Guo Xingying Tang Yang Guo Shuzhong Wang 《International Journal of Hydrogen Energy》2017,42(31):19819-19828
Systematical corrosion tests of austenitic stainless steel 316L exposed to sewage sludge SCWO (supercritical water oxidation) were conducted in a batch stirred reactor with hydrogen peroxide as oxidant. Experiment conditions such as temperature, oxidation coefficient, pH value, corrosion medium, were chosen mainly keeping in mind the place and environment of reactions (i.e. surrounding transpiring wall). The exposed samples were ultimately analyzed by weight measurement, scanning electron microscopy in conjunction with energy dispersive spectroscopy, and X-ray diffraction analysis. The results show that severe pitting corrosion occurred as the sample was exposed to complicated environments, and different oxides including Fe3O4, FeCr2O4 and MoO3 were found on the sample surface. The corrosion rate at all test conditions (360–450 °C pH = 5.2–10.05, oxidation coefficient of 0–2.0, sewage sludge or its SCWO reactor effluent) was in the range of 0.12–0.66 mm/y, and it increased as temperature and OC increased at supercritical conditions. Moreover, potential corrosion mechanism of 316L in sewage sludge SCWO is proposed, and influences of operating parameters on 316L corrosion properties are summarized. 316L and reactor effluent could be considered as transpiring wall material and transpiring water in sewage sludge SCWO with transpiring wall reactor, respectively. 相似文献
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针对不锈钢衬里常处于强腐蚀介质、高温高压工况下,存在着应力腐蚀、晶间腐蚀、点腐蚀等问题,介绍了带不锈钢衬里压力容器的结构及常用的衬里方法,重点分析了这些腐蚀产生的机理及应该采取的措施,最后总结出不锈钢衬里在定期检验中需要重点注意的问题。 相似文献