Experimental study on the effect of H2S and SO2 on high temperature corrosion of 12Cr1MoV

Aiming at the high temperature corrosion in a coal-fired boiler,the effect of H2S and SO2 on the corrosion of 12 CrlMoV under the water wall condition has been investigated by experiments.The results indicate that H2 S can promote the corrosion significantly,and the coarse porous oxide film formed cannot stop the progress of corrosion.While SO2 presents little effect on the corrosion.The main composition of the surface of 12 CrlMoV corrosion products is Fe2 O3.With H2S in the atmosphere,the corrosion gradually develops into deeper layers by forming FeS,FeO and Fe2 O3 alternately.The corrosion rate is doubled for every 50℃ inerease in temperature at 400-500℃.

Corrosion Rate of Hydrogenation to C110 Casing in High H_2S Environment

The corrosion behavior of C110 bushing at high temperature and high pressure with a high H2S / CO2 was studied, and a basis for the materials selection of sour gas well bushing was provided in H2S, CO2 and saline coexisting environment. Under acidic condiction, hydrogen atoms greatly entered into the material and caused the material properties changed. Weight loss method was used to study the corrosion rate of hydrogen charging samples and original untreated samples in simulated oil field environment. PAR2273 electrochemical workstation was used to examine the electrochemical performance of samples untreated, hydrogen charging after reacting in autoclave. The corrosion product film was observed through SEM. The experimental results show that sample with hydrogen charging has a much more obvious partial corrosion and pitting corrosion than the untreated blank sample even the downhole corrosion speed of bushing is increased after being used for a period of time. Polarization curve shows the corrosion tendency is the same between sample with or without hydrogen charging and corrosion tendency is reduced by corrosion product film. A layer of dense product film formed on the surface of samples provides a certain protective effect to the matrix, but cracked holes which will accelerate partial corrosion of the sample were also observed.

Effect of Plastic Deformation and H_2S on Dynamic Fracture Toughness of High Strength Casing Steel

The effects of plastic deformation and H2 S on fracture toughness of high strength casing steel（C110 steel） were investigated. The studied casing specimens are as follows： original casing, plastic deformation（PD） casing and PD casing after being immersed in NACE A solution saturated with H2S（PD＋H2S）. Instrumented impact method was employed to evaluate the impact behaviors of the specimens, meanwhile, dynamic fracture toughness（JId） was calculated by using Rice model and Schindler model. The experimental results show that dynamic fracture toughness of the casing decreases after plastic deformation. Compared with that of the original casing and PD casing, the dynamic fracture toughness decreases further when the PD casing immersed in H2 S, moreover, there are ridge-shaped feature and many secondary cracks present on the fracture surface of the specimens. Impact fracture mechanism of the casing is proposed as follows： the plastic deformation results in the increase of defect density of materials where the atomic hydrogen can accumulate in reversible or irreversible traps and even recombine to form molecular hydrogen, subsequently, the casing material toughness decreases greatly.

Corrosion Behavior of 110S Tube Steel in Environments of High H_2S and CO_2 Content

The corrosion behavior of the 110S tube steel in the environments of high H2 S and CO2 content was inves- tigated by using a high-temperature and high-pressure autoclave, and the corrosion products were characterized by scanning electron microscopy and X ray diffraction technique. The results showed that all of the corrosion products under the test conditions mainly consisted of different types of iron sulfides such as pyrrhotite of Fe0.95 S, mackinaw- ite of FeS0.9, Fe0. 985 S and FeS, and the absence of iron carbonate in the corrosion scales indicated that the corrosion process was controlled by H2S corrosion. The corrosion rate of the 110S steel decreased firstly and then increased with the rising of temperature. The minimum corrosion rate occurred at 110 ℃. When the H2 S partial pressure PH2s below 9 MPa, the corrosion rate declined with the increase of PH2s. While over 9 MPa, a higher PH2s resulted in a faster corrosion process. With the increasing of the CO2 partial pressure, the corrosion rate had an increasing trend. The morphologies of the corrosion scales had a good accordance with the corrosion rates.

高铁高硫铝土矿氧压提质脱硫降铁研究

高铁高硫铝土矿的提质利用对于保障我国铝工业战略矿产资源安全具有重要意义。针对含铁13.66%、硫16.24%的一水硬铝石型高铁高硫铝土矿,主要铁、硫物相为黄铁矿,绘制了Fe-S-H2O系电位-pH图。结果表明,当体系pH小于Fe3+水解临界pH时,能够实现铁、硫的同步浸出。采用加压浸出法处理,在液固比4 mL/g、浸出温度170℃、氧气分压0.20 MPa、保温时间2 h条件下,铁、硫浸出率分别为94.08%和98.34%,浸出渣铁、硫含量分别为1.23%和0.41%,XRD结果表明,浸出渣物相主要为一水硬铝石,实现了高铁高硫铝土矿的提质。浸出液主要溶质为硫酸铁,具有铁、硫进一步资源化利用的潜力。

电站锅炉水冷壁高温腐蚀成因与对策研究

亚临界以上参数的大型电站锅炉水冷壁温较高,低NOx分级燃烧技术的应用使主燃烧区域处于贫氧状态,往往导致严重的高温腐蚀。选取某300 MW电站锅炉发生高温腐蚀后的水冷壁管为研究对象,通过割管取样、电镜表征分析等手段,对高温腐蚀原因、类型进行了研究。研究结果表明,腐蚀产物中含有大量FeS,属于典型的硫化物型腐蚀。腐蚀管样表面覆盖有肉眼可见的蓝色、黄绿色物质,其主要成分为铁的氧化物、铁的硫化物以及锌的硫化物;硫化物在蓝色物质中主要为FeS晶体,晶体尺寸大小在10～20μm,呈现规则六方晶体结构;黄绿色物质则主要为ZnS,同时,腐蚀管样表面还发现大量未燃尽碳颗粒,表明炉内配风不合理,存在火焰中未燃尽的煤粉和飞灰颗粒刷墙现象。燃烧器改造后,进行了冷态空气动力场烟花调试,发现整体切圆状况良好,符合设计要求,无偏离炉膛几何中心。一次风切圆直径为790 mm,基本与设计值吻合,各层气流相对舒展,无明显贴壁现象,炉内烟花模拟的火焰充满度良好,炉内空气动力场状况明显改善;从改造后热态运行结果看,锅炉对煤种适应性有极大改善,燃烧稳定性和防结渣能力均有较大提升,在贫煤50%掺烧比例下,锅炉出力可保持800 t/h以上连续运行,看火孔火焰均匀,未发现大块连续结焦现象,高温腐蚀现象明显减轻。

鄂尔多斯盆地东北部马五_(1+2)亚段岩石类型及沉积环境

受多期岩溶叠合改造影响,鄂尔多斯盆地东北部奥陶系马五_(1+2)亚段的原岩组构遭受破坏,制约了对原始沉积环境及沉积相的恢复研究。基于岩芯、薄片及阴极发光研究,通过原岩组构恢复,在区内识别出5种主要的原始碳酸盐岩类型及7种成岩作用产物岩石类型,并总结出5种岩石类型组合,分别形成于局限—蒸发台地内的颗粒滩、滩间海、丘滩复合体、台坪和局限瀉湖沉积环境。纵向上可构成局限瀉湖—颗粒滩—台坪、局限瀉湖—丘滩复合体—台坪等4种典型的向上变浅沉积序列。结果表明,颗粒岩类与含膏模孔泥(粉)晶云岩类是盆地东北部马五_(1+2)亚段最主要的原始岩类,并发育有一定规模的藻黏结岩和泥晶云岩,其中含膏模孔泥(粉)晶云岩与丘、滩向上变浅序列密切相关。这些认识将为深化区内古环境和储集岩类研究提供依据。

高含硫环境下20号无缝钢管腐蚀行为研究

通过显微维氏硬度计、扫描电子显微镜(SEM)、能谱仪(EDS)、X射线衍射(XRD)仪对第五采气厂高含硫环境下20号无缝钢管的腐蚀行为进行分析和研究。结果表明:20号无缝钢管的显微硬度均值为228 Hv,屈服强度为419 MPa,抗拉强度为573 MPa,延伸率为18.3%;对样品内外表面腐蚀产物的成分和相分析可知,样品外表面的腐蚀产物主要为氧化铁且伴有少量的FeS 2;样品内表面腐蚀产物主要为FeS 2和Fe 2O 3。因此,第五采气厂高含硫气井中的H 2S会对集输气管道造成一定程度的腐蚀破坏。

新型电子投捞式DPT试井技术在超深高压高含H_2S井的改进和应用

井下压力监测工艺(DPT)是将带有压力计的悬挂组合装置置放于特定深度录取井底各项动态参数的测试工艺。塔河油田油藏大部分具有高温、高压、超深、高H2S等特征,新型电子投捞式DPT配套工艺的改进应用,有效避免了上述井况下的施工风险,提高时效并大大降低施工成本。

基于ZnCeS的荧光猝灭型硫化氢气体传感器

采用高温固相法制备了Zn_(0.97)Ce_(0.03)S光学气敏材料,搭建了一套由Zn_(0.97)Ce_(0.03)S气敏薄膜、简易气室、光纤光谱仪及配套软件构成的气体传感器用以检测H_2S气体.实验结果表明:该H_2S气体传感器的检测限为4.28ppm,稳定性好、灵敏度高、抗干扰能力强.采用荧光猝灭的Stern-Volmer方程分析发现,H_2S气体浓度与敏感元件荧光猝灭信号呈良好的线性对应关系,且整个传感器制作简单、响应迅速,可实现对低浓度H_2S气体的高灵敏检测.

Hydrogen Permeation Behaviors of X52 Pipeline Steel in NACE A Solution with Saturated H_2S/CO_2

With the aid of hydrogen permeating devices, the hydrogen permeation behaviors of X52 pipeline steel in NACE A solution with saturated H2S/CO2 were studied under the conditions of different ambient temperatures and pH values, and the hydrogen permeation behaviors of X52 pipeline steel in weld seam zone were comparatively studied. The experimental results show that the hydrogen permeation coefficient value is directly proportional to the time required for reaching the saturation anode current and inversely proportional to the saturation anode current, and the hydrogen permeation coefficient is influenced by the corrosion scales; the temperature is directly proportional to the saturation anode current, and the hydrogen permeation coefficient is influenced by the temperature and corrosion scales, heat-affected zone and matrix zone in NACE A solution with saturated H2S/CO2 at normal temperature. The hydrogen permeation coefficient in weld seam zone is larger than that in heat-affected zone which is further larger than that in matrix zone.

Corrosion Behavior of X52 Anti-H_2S Pipeline Steel Exposed to High H_2S Concentration Solutions at 90℃

Initial corrosion kinetics of X52 anti-H2S pipeline steel exposed to 90 ℃/1.61 MPa H2S solutions was investigated through high temperature and high pressure immersion tests. Corrosion rates were obtained based on weight loss calculation. The corrosion products were analyzed by scanning electron microscopy （SEM）, transmission electron microscopy （TEM）, X-ray diffraction （XRD） and electron probe micro-analysis （EPMA）. The initial corrosion kinetics was found to obey the exponential law. With increasing immersion time, the main corrosion products changed from iron-rich mackinawite to sulfur-rich pyrrhotite. The corrosion films had two layers： an inner fine-grained layer rich in iron and an outer columnar-grained layer rich in sulfur. The corrosion film formed through the combination of outward diffusion of Fe2＋ ions and inward diffusion of HS^- ions. The variation of the corrosion products and compaction of the corrosion layer resulted in a decrease in the diffusion coefficient with increasing immersion time. The double-layered corrosion film formed after long time immersion acted as an effective barrier against diffusion.

S^(2-)对A710钢在NaCl溶液中腐蚀行为的影响

采用室内静态挂片失重实验方法、动电位极化法、FE-SEM表面微观观察和XRD物相分析等技术,研究了A710钢在高S^(2-)含量的3.5%NaCl溶液中的腐蚀行为。结果表明:S^(2-)的加入能够增强钢基体表面的活性,导致维钝电流密度增大,钝化区间变窄,均匀腐蚀速率增加;在含有S^(2-)的NaCl溶液中形成的腐蚀产物膜结构疏松,存在孔隙和裂纹,促进了膜下点蚀的发生。