W火焰锅炉高温腐蚀问题分析及调整策略

为缓解上安电厂2号锅炉完成低氮燃烧改造后下炉膛水冷壁出现的严重硫化物高温腐蚀问题,针对该厂2号W火焰锅炉燃烧方式的特点及设备状况,分析得出锅炉进行分级送风、煤粉浓淡分离、增加燃烬风等低氮燃烧改造,使得下炉膛区域由过氧燃烧转变为欠氧燃烧是引起高温腐蚀的主要原因,并提出从运行氧含量、燃烬风门开度、外二次风旋流强度、煤质和运行磨煤机组合等几个方面寻优的燃烧调整策略。结果表明,根据各项测试最优结果进行优化组合后满足O_2含量2%,CO含量0.2%条件的测点个数明显增加,下炉膛壁面还原性气氛明显减弱,高温腐蚀问题得到较大缓解,提高了机组运行的安全性,保证最优工况下选择性催化还原法(SCR)入口的NO_x浓度低于改造设计值的800 mg/m~3,表明调整策略同时兼顾了环保运行的要求。     

Evolution of the corrosion layer of Q235 steel in simulated fire-scene smoke

The ability to accurately identify fire patterns is the fundamental requirement for fire investigations. The corrosion layers of steel in fire scenes exhibit three distinct characteristics. First, due to steel's nonflammable nature, steel patterns can be preserved better at the fire site than patterns formed on other combustible materials; second, both the high temperature and the smoke during the fire affect the high-temperature oxidation process; and third, the corrosion layer of steels inevitably undergoes further evolution after the fire because of the subsequent room-temperature corrosion. This study focuses on investigating Q235 steel because of its extensive use in construction and vehicles. The pattern evolution processes of high-temperature oxidation at elevated temperatures in air, polyethylene (PE), and polyvinyl-chloride (PVC) combustion smoke and the corresponding subsequent corrosion at room temperature were systematically investigated from the perspective of macroscopic and microscopic morphology. The results showed that the smoke atmosphere played an important role in the formation of the corrosion layer of Q235 steel. Compared with samples oxidized in air, samples oxidized in PE combustion smoke exhibited a uniform and dense oxide layer on the surface, which inhibited the corrosion at room temperature further. The PVC combustion smoke accelerated the high-temperature oxidation of the sample, and its influence on the subsequent room-temperature oxidation process was closely correlated with the temperature of the high-temperature oxidation. The results of this study provide important references for understanding the formation of the corrosion layer of Q235 steel for fire investigations.     

高温水采暖系统内部氧腐蚀

对阜康冶炼厂高温水采暖系统内部产生氧腐蚀的原因进行分析，采取相应的措施，收到良好的效果     

CuO助剂对铁铬系CO高温变换催化剂性能的影响

考察了CuO的不同前驱体对铁铬系CO高温变换催化剂反应性能的影响，研究发现，CuO助剂可改善催化剂的低温活性，以硝酸铜的加入形式效果较为显著。对样品进行了XRD、BET、H_2- TPR和XPS表征，结果表明， CuO助剂进入了Fe₃O₄的反尖晶石结构的八面体空隙，置换Fe²⁺与Fe₃O₄发生相互作用，改变了催化剂的还原特性，使^_Fe2O3还原为Fe₃O₄的还原温度降低了100 ℃左右。铜在催化剂的表面以Cu(OH)₂、CuO和Cu₂O三种形态存在，因Cu²⁺取代Fe²⁺的八面体配位单元，致使配位场稳定化能降低，催化剂表面容易产生O^2－缺位，所产生的新的活性中心极易吸附OH^－，使催化剂在低汽气比条件下参与CO变换反应，具有高活性且遏制烃类副产物的生成。     

四元溴化盐对碳钢的高温腐蚀实验研究

熔盐是一种高效传热蓄热工质,其在熔盐传热蓄热系统中对熔盐泵、阀门、各种传感器、管道等金属材料设备的腐蚀特性是熔盐应用的限制因素之一,因此确定熔盐对金属材料的腐蚀性能至关重要。为研究四元溴化盐对碳钢(Q235)的高温腐蚀性能,以浸没法在450℃温度下进行碳钢样片的静态腐蚀实验,得到样片在溴化盐腐蚀环境中的腐蚀动力曲线,并对样片腐蚀区域进行扫描电镜和X射线物相分析。实验结果表明,在高温溴化盐腐蚀环境中,碳钢样片被腐蚀的质量损失量随时间延长而增加,腐蚀360h后样片质量损失达到24.14mg/cm²;样片表面产生了电化学腐蚀,腐蚀产物以铁、锰的氧化物为主。     

海上油田腐蚀探析及防护

通过分析南海某油田现场主要技术指标,确定导致腐蚀的主要影响因素包括高矿化度的水质、高含量的CO2以及H2S和硫酸盐还原菌(SRB);其中SRB是此油田腐蚀产生的最重要影响因素,也是产生点蚀的关键因素。通过在油井井下加入季铵盐衍生物类型的缓蚀剂,并定期应用季铵盐复合杀菌剂对整个系统进行杀菌处理,使油田的腐蚀得到了很好的控制。     

工业锅炉炉水中HEDP缓蚀特性研究

使用电化学阻抗法及Tafel极化法在模拟低压工业锅炉炉水介质中研究了HEDP对20#碳钢的缓蚀性能,并探讨了炉水中Ca2+、Cl-以及SO42-对HEDP缓蚀性能的影响。实验结果表明:在模拟炉水介质中,当HEDP投加量为25 mg/L时,其对碳钢具有最佳的缓蚀效果;HEDP对碳钢腐蚀的抑制主要作用于阳极失电子反应,HEDP是一种以抑制阳极为主的缓蚀剂;炉水中Ca2+的存在会影响HEDP对碳钢电极的极化过程;Cl-、SO42-等侵蚀性阴离子会促进腐蚀的加剧,影响HEDP的缓蚀性能。     

氯碱生产环境下金属阳极 电解槽的腐蚀探讨与防护方法研究

金属阳极电解槽的腐蚀严重影响了氯碱生产整个装置的安危以及产品的收率与质量。实验模拟氯碱生产中电解槽所处的恶劣介质环境,运用腐蚀失重法,揭示了电解槽的腐蚀行为与影响因素。实验结果表明：在氯碱生产环境下,当电解槽温度为85~90 ℃、阴极液中氢氧化钠质量分数为8%~12%、阳极液pH＜4时,电解槽的腐蚀速率最低。在此基础上,制定出了可行的电解槽腐蚀防护措施。     

盐酸介质金属缓蚀剂最新进展

对盐酸介质中金属材质腐蚀的机理以及研究现状进行了分析和概述。目前,人们认识到金属材质在盐酸溶液中腐蚀速度与酸度和氯离子浓度有关。而针对就盐酸溶液中的氯离子以及氢离子在金属的腐蚀过程发挥多大的功效,以及金属材质的阳杉阴极反应是如何进行的动力学问题的研究成为该领域的主要趋势,以解决金属材料在盐酸介质中腐蚀问题。     

Corrosion and corrosion inhibition of nickel in HClO4 solutions using the EQCM technique

Application of the electrochemical quartz crystal microbalance (EQCM) to the study of metal corrosion and its inhibition is rather recent. Among the advantages of this technique are its very high sensitivity and the possibility of simultaneous mass variations and voltammogram recording. These characteristics suggest the use of the EQCM for research in very low corrosion rate conditions. This paper reports the results of EQCM measurements on the corrosion inhibition rates of Ni in 0.1m HClO4, in the absence and presence of different inhibitors in free corrosion conditions, for following inhibitors: acridine (A), benzyl quinolinium chloride (BQCl), dodecyl quinolinium bromide (DDQBr), tributylbenzyl ammonium iodide (TBNI) and potassium iodide (KI). The corrosion rate was reduced considerably by KI and TBNI. DDQBr showed a good inhibitive efficiency, while BQCl had only a small effect, and A stimulated corrosion of the Ni. Voltammograms at different scanning rates and the mass variation in the same solutions were recorded. Comparison of the current density and the mass changes provided the basis for a qualitative interpretation of the passivation of Ni and the mechanism of action of the different inhibitors.     

Corrosion and corrosion inhibition of nickel in HClO4 solutions using the EQCM technique

Application of the electrochemical quartz crystal microbalance (EQCM) to the study of metal corrosion and its inhibition is rather recent. Among the advantages of this technique are its very high sensitivity and the possibility of simultaneous mass variations and voltammogram recording. These characteristics suggest the use of the EQCM for research in very low corrosion rate conditions. This paper reports the results of EQCM measurements on the corrosion inhibition rates of Ni in 0.1m HClO4, in the absence and presence of different inhibitors in free corrosion conditions, for following inhibitors: acridine (A), benzyl quinolinium chloride (BQCl), dodecyl quinolinium bromide (DDQBr), tributylbenzyl ammonium iodide (TBNI) and potassium iodide (KI). The corrosion rate was reduced considerably by KI and TBNI. DDQBr showed a good inhibitive efficiency, while BQCl had only a small effect, and A stimulated corrosion of the Ni. Voltammograms at different scanning rates and the mass variation in the same solutions were recorded. Comparison of the current density and the mass changes provided the basis for a qualitative interpretation of the passivation of Ni and the mechanism of action of the different inhibitors.     

腐蚀金属对甲醇羰化合成醋酸反应的影响

结合工业生产催化体系中存在的腐蚀金属,研究了其对羰基合成醋酸反应的影响.在高压反应釜中,通过添加不同浓度的醋酸亚铁或醋酸镍考察腐蚀金属铁和镍对铑基催化剂和铱基催化剂反应活性和选择性的影响,并利用平行反应器在模拟闪蒸条件下考察腐蚀金属对主催化剂稳定性的影响.结果表明,少量腐蚀金属铁或镍的存在对铑催化羰基合成醋酸的反应活性...     

模拟试验法选用锅炉化学清洗缓蚀剂

通过静态和动态模拟试验,考察了锅炉清洗过程中Fe3 和流速对腐蚀速率的影响,并评价了4种缓蚀剂.结果表明,Fe3 具有加速清洗液腐蚀碳钢的作用,使20A碳钢的腐蚀速率成倍增大;清洗液中的腐蚀速率均随清洗流速的增大而增大,但各种缓蚀剂的缓蚀效果优劣的依次关系在3种流动状态下不变.通过模拟试验能够找出锅炉清洗过程中的安全清洗流速和缓蚀剂安全添加量,JF-106安全清洗流速为0.5m/s,添加量至少为0.2%,其他缓蚀剂清洗流速小于0.5m/s.     

低压锅炉运行中的氧腐蚀及新型除氧剂的应用

阐述了低压锅炉运行中氧腐蚀的特征、机理、影响因素以及危害,表明低压锅炉运行中的腐蚀主要是氧腐蚀,介绍了TGS—A新型除氧剂的除氧机理和现场应用,表明TGS—A除氧剂除氧效果明显,能够有效地控制锅炉的氧腐蚀,延长锅炉使用寿命,保证锅炉安全运行。最后阐述了锅炉除氧对锅炉安全经济运行的意义。     

The CMAS corrosion behavior of high-entropy (Y0.2Dy0.2Er0.2Tm0.2Yb0.2)4Hf3O12 hafnate material prepared by ultrafast high-temperature sintering (UHS)

High-temperature molten calcium-magnesium-alumina-silicate (CMAS) corrosion has become a fatal factor for the failure of aero-engine thermal barrier coatings. In this study, a promising entropy-stabilized (Y_0.2Dy_0.2Er_0.2Tm_0.2Yb_0.2)₄Hf₃O₁₂ (5YH) hafnate was prepared by the emerging ultrafast high-temperature sintering (UHS), and its corrosion and wetting behavior of molten CMAS were investigated. For the corrosion mechanism, the precipitation of the high-entropy apatite phase promotes the formation of the HfO₂ phase, and it can improve the density and stability of the slow-growing reaction layer, hindering the further penetration of molten CMAS. At 1300 ℃, a reaction layer with a three-layered morphology is generated, resulting from the decreased viscosity of the molten CMAS. Moreover, computational analysis shows that molten CMAS on the 5YH surface has a larger contact angle (17°) than traditional YSZ (13°), and the spreading area is about 90 % of traditional YSZ, which benefits for its good CMAS corrosion resistance.     

硫磺制酸装置露点腐蚀问题的分析

分析了硫磺制备酸容易发生露点腐蚀的原因。硫磺中的有机物、水分、游离硫酸均可能增加炉气水分含量，相应提高了炉气露点温度，加之省煤器进水温度低，则容易发生露点腐蚀。采用优质硫磺作原料，在省煤器低温段采用热管元件等可有效地解决硫磺制酸露点腐蚀问题。     

Andalusite transformation and properties of andalusite-bearing refractories fired in different atmospheres

We found in our research that andalusite aggregate fired in a reducing atmosphere exhibits a lower mullitization rate than that fired in an air atmosphere. For investigating the effect of atmosphere on the transformation of andalusite and the properties of andalusite-containing refractories, andalusite powder (≤0.074?mm) and refractories containing andalusite aggregate (3–1?mm) were fired in air and carbon embedding, respectively. The phases and microstructure of the andalusite fired in both atmospheres were characterized by X-ray diffraction and scanning electron microscopy, respectively. The correlations of the properties of the andalusite-bearing refractories with the firing atmospheres were investigated in terms of volume stability, mechanical strength, and thermal shock resistance. The difference in the properties of the refractories was discussed with respect to the varied transformation rates of andalusite, and in terms of the different viscosities of the silica-rich glass caused by the different atmospheres.     

盐酸介质中新型缓蚀剂研发进展

对盐酸介质中金属材质腐蚀的机理以及研究现状进行了分析和概述。对缓蚀剂的研发做出了展望。     

A3碳钢在模拟油田水中的腐蚀行为研究

用极化曲线法探讨了A3碳钢在模拟油田水中的腐蚀电化学行为。试验了在不同矿化度、pH值、溶解氧及含S2-的模拟油田水中A3碳钢的腐蚀行为,并用电化学方法研究了缓蚀剂的缓蚀效果。结果表明,随着矿化度的增加,温度的升高,腐蚀速率增大;pH值在7~8之间为碳钢的钝化区;在中性或碱性条件下,碳钢的腐蚀主要受溶解氧的影响,溶解氧含量越高,腐蚀越严重;S2-的存在消除了溶解氧的影响,改变了腐蚀产物膜的组成,从而影响缓蚀剂的选择。     

Influence of atmospheres on the dielectric properties of calcium copper titanate ceramics

Calcium Copper Titanate Ceramics (CaCu₃Ti₄O₁₂; CCTO) are useful as capacitors because of the large dielectric constant. This study investigated the effect of testing atmospheres such as air and dry N₂ on the stability and reproducibility of the electrical properties displayed by CCTO ceramics. Solid-state reaction method is used to synthesize phase pure CCTO powders, which are used to fabricate dense samples by sintering. Samples with different microstructures are obtained by sintering at different temperatures of 1070 and 1100°C. AC impedance spectroscopy is used to study the effects of testing atmospheres, temperatures, microstructures, and frequency on the dielectric properties of the sintered samples. Highly irreproducible dielectric properties are observed upon testing in ambient conditions. Stable and reproducible dielectric properties are only obtained in dry N₂. Re-exposing the same CCTO samples back into ambient air after treating in dry N₂ restored irreproducibility. The results from this study suggested that the role of moisture/air in the ambient on the dielectric properties should not be over-looked and is expected to play a key role in controlling the stability of dielectric properties of CCTO. This new approach of characterizing the CCTO ceramics can be used as guidelines to eliminate hysteresis due to ambient atmosphere and to produce stable and reproducible dielectric properties useful as capacitors.