During CO2 sequestration, injected gas contains various carbon source impurities. This work conducted in situ electrochemical testing on P110 tubing steel at 90 degrees C under conditions where the carbon source impurity NO2 content was 0, 100 ppm, and 900 ppm respectively. Impedance spectroscopy and dynamic potential scanning polarisation curve testing techniques were employed to characterise the microstructural information of different post-corrosion films, product film/substrate interfaces, and product film/corrosion medium interfaces. Results indicate that under pure CO2 conditions, the capacitive arc radius is maximal, with a dense and highly protective corrosion product film. The charge transfer resistance (Rt) is 220.674 Omega & sdot;cm2, and the anodic active area is suppressed, resulting in a low and uniform corrosion rate. The introduction of NO2 significantly compromises the integrity and stability of the corrosion product film, leading to intensified localised corrosion. As NO2 concentration increased from 0 ppm to 900 ppm, the electrode surface potential distribution became more dispersed, the anodic current peak intensified, and the number of active sites increased. Consequently, Icorr rose, Ecorr shifted negatively, the capacitive arc radius decreased, and Rt dropped sharply. These changes significantly exacerbated both generalised and localised corrosion tendencies in the material.

During CO2 sequestration, the injected gas contains various non-CO2 gases associated with carbonaceous materials, namely carbon source impurities. This study conducted in situ electrochemical tests on P110 tubing steel at 90 degrees C under conditions of zero carbon source impurities, 100 ppm SO2 and 100 ppm NO2 coexistence. Impedance spectroscopy and dynamic potential scanning polarography techniques characterised microstructural information concerning post-corrosion film layers, product film/substrate interfaces, and product film/corrosion medium interactions. Results indicate that under pure CO2 conditions, a dense and protective FeCO3/CaCO3 corrosion product film forms on the P110 steel surface. This film exhibits a large capacitive arc radius and a high charge transfer resistance (Rt) of 220.674 Omega & sdot;cm2, suppressing the anodic active area and resulting in low, uniform corrosion rates. The introduction of SO2 and NO2 significantly disrupted the integrity and stability of the corrosion product film, inducing dynamic enhancement and spatial expansion of local electrochemical activity. Within the CO2 + 100 ppm SO2 + 100 ppm NO2 coupled system, the corrosion product film transformed into a loose, porous composite film comprising FeS, FeSO4, and Fe(NO3)3. The capacitive arc radius markedly diminished, the corrosion current density (Icorr) increased, and Rt plummeted to 5.270 Omega & sdot;cm2. Concurrently, the number of active anodic sites increased, with peak current density progressively rising over corrosion time, markedly enhancing localised corrosion susceptibility. This study first reveals the synergistic acceleration mechanism of localised corrosion in P110 steel under CO2 storage conditions when SO2 and NO2 coexist at elevated temperatures and pressures. It provides crucial electrochemical evidence for predicting the service life and selecting materials for pipelines under impurity-containing CO2 geological storage conditions.

During the CO2 storage process, the corrosive effect of various carbon source impurities on metallic materials must be considered. In this study, high-temperature and high-pressure simulation tests, high-temperature and high-voltage piezoelectric chemical tests and filament electrode tests were performed on P110 tubing steel at 90 degrees C with carbon source impurity NO2 content of 100 and 900 ppm. The results showed that, in a pure CO2 environment, corrosion was mainly uniform and that the corrosion product film was mainly composed of dense FeCO3 and a small amount of CaCO3, with trace amounts of Fe2O3/Fe3O4 and FeOOH present locally. In a 100 ppm NO2 environment, the introduction of NO2 significantly intensifies corrosion. The corrosion product film thickens and becomes loose, consisting mainly of Fe3O4 and trace amounts of Fe(NO3)3, while the FeCO3 content decreases. In a 900 ppm NO2 environment, the corrosion product film has a porous honeycomb structure and is mainly composed of Fe3O4 and Fe(NO3)3, with further inhibition of FeCO3. An increase in NO2 concentration promotes the formation of Fe3+ oxidation products, which disrupts the stability of the FeCO3 film.

During the process of CO2 storage, the corrosive effect of various carbon source impurities on metallic materials cannot be ignored. This work conducted high-temperature and high-pressure simulation tests on P110 tubing steel under the conditions of 90 degrees C and the coexistence of 0, 100 ppm SO2 and 100 ppm NO2 carbon source impurities. The film-forming mechanism and corrosion characteristics of the corrosion product film of P110 tubing steel were analyzed by using techniques such as laser confocal, SEM, EDS, EPMA, Raman spectroscopy, XRD and XPS. The results show that in a pure CO2 environment, a corrosion product film primarily composed of crystalline, dense, and protective FeCO3 and CaCO3 forms on the surface of P110 tubing steel. Corrosion is predominantly uniform, with a relatively low pitting rate. However, in the presence of both SO2 and NO2, these gases undergo a disproportionation reaction to generate strong acids such as H2SO4 and HNO3. This triggers competitive electrochemical processes, leading to the formation of a loose, porous composite product film containing non-protective FeS, FeSO4, and Fe(NO3)3. This film exhibits structural instability and numerous defects. Whilst it marginally mitigates uniform corrosion, it markedly exacerbates localised pitting corrosion, with maximum pitting depths reaching 122.8 mu m, posing a severe threat to material integrity.

During the CO 2 storage process, the corrosive effect of various carbon source impurities on metallic materials must be considered. In this study, high‐temperature and high‐pressure simulation tests, high‐temperature and high‐voltage piezoelectric chemical tests and filament electrode tests were performed on P110 tubing steel at 90°C with carbon source impurity NO 2 content of 100 and 900 ppm. The results showed that, in a pure CO 2 environment, corrosion was mainly uniform and that the corrosion product film was mainly composed of dense FeCO 3 and a small amount of CaCO 3 , with trace amounts of Fe 2 O 3 /Fe 3 O 4 and FeOOH present locally. In a 100 ppm NO 2 environment, the introduction of NO 2 significantly intensifies corrosion. The corrosion product film thickens and becomes loose, consisting mainly of Fe 3 O 4 and trace amounts of Fe(NO 3 ) 3 , while the FeCO 3 content decreases. In a 900 ppm NO 2 environment, the corrosion product film has a porous honeycomb structure and is mainly composed of Fe 3 O 4 and Fe(NO 3 ) 3 , with further inhibition of FeCO 3 . An increase in NO 2 concentration promotes the formation of Fe 3+ oxidation products, which disrupts the stability of the FeCO 3 film.

为了研究3Cr钢在不同CO2、H2S腐蚀介质中耐蚀性,对3Cr钢分别在1 MPa CO2、0.3 MPa H2S及1 MPa CO2+0.3 MPa H2S腐蚀环境中的腐蚀速率和电化学性能进行测试,同时采用SEM、EDS和XRD等手段对上述三种腐蚀环境中的腐蚀产物进行分析对比.结果表明,3Cr钢在1 MPa CO2环境下腐蚀速率最大,通过对腐蚀产物进行分析,发现其表面未形成连续分布且具有致密性腐蚀产物保护膜是其腐蚀速率高的主要原因.电化学测试发现3Cr钢EIS阻抗在1 MPa CO2中呈现单容抗弧,而在0.3 MPa H2S和1 MPa CO2+0.3 MPa H2S环境中呈现双容抗弧,进一步印证了其在1 MPa CO2环境中耐蚀性较差的结果.

The work aims to observe the corrosion characteristics of sulfate reducing bacteria （SRB） / saturated CO 2 anti-microbial corrosion pipe and to explore the effect of SRB on CO 2 corrosion. Through the bacterial culture experiment in the constant temperature 40℃ biochemical incubator， the 15-day growth curve of planktonic SRB in the environment with and without saturated CO 2 was obtained by using the method of blood plate counting. The effects of SRB， saturated CO 2 and SRB+ saturated CO 2 （three different environments） on the corrosion rate were obtained by immersion corrosion test in a constant temperature 40 ℃ biochemical incubator. The surface morphologies after corrosion in three different environments were analyzed by scanning electron microscope （SEM）. The composition and phase composition of corrosion products in three different environments were analyzed by energy dispersive spectroscopy （EDS） and X-ray diffractometer （XRD）. The corrosion electrochemical tests were carried out in a 40℃ water bath to study the effects of three different environments on the corrosion of microbial corrosion pipes. The results of bacterial culture in the presence and absence of saturated CO 2 showed that CO 2 could be used as a delayed carbon source for the growth of SRB and provide energy for the secondary growth of SRB. The results of corrosion immersion test showed that the corrosion rate was the highest in saturated CO 2 environment， the second in SRB environment and the lowest in SRB+ saturated CO 2 environment. The results of SEM analysis showed that the corrosion product film formed in CO 2 environment showed serious cracking phenomenon， and the corrosion was the most serious; many bacteria gathered together in SRB environment and adhered to EPS to form a similar network biofilm， which was more and relatively continuous than in the SRB+ saturated CO 2 environment. The results of EDS analysis showed that in the environment containing SRB， the sulfur element detected in the environment was higher than that in the aseptic environment due to the reduction of sulfate to H 2 S after the corrosion reaction of SRB， the reaction of H 2 S with Fe 2+ to form FeS and the contact of a little FeS with air to form simple substance S. The results of XRD analysis showed that in saturated CO 2 environment， the corrosion products were mainly in FeCO 3 ， Fe 2 O 3 and Fe 3 O 4 ; in the SRB environment， and the corrosion products were mainly in FeS， FePS 3 ， Fe 3 O 4 ， Fe 2 O 3 and simple substance S， in the SRB + saturated CO 2 environment， and only Fe diffraction peaks were detected. The electrochemical test results show that in the three environments， the slope of cathodic Tafel is larger than that of anode Tafel， and the corrosion is controlled by cathodic reaction. The whole corrosion process is affected by CO 2 corrosion， normal bacterial growth and metabolism， and the film is easy to crack and fall off. After immersion for 15 days， the polarization resistance shows the law of R p（SRB） ＞Rp （SRB+saturated CO2） ＞Rp （CO2） corrosion and SRB corrosion influence each other. In SRB+ saturated CO 2 environment， the formation of the biofilm improves the adhesion of the corrosion product film， reduces the corrosive ions passing through the film， and slows down the corrosion， so the existence of SRB can obviously inhibit the CO 2 corrosion of the microbial corrosion pipe.

为了研究5Cr套管钢在不同CO2分压下的腐蚀特性,进行了5Cr套管钢高温高压腐蚀失重和高温高压电化学试验,并采用XRD、SEM和EDS等手段对其腐蚀产物进行微观分析.结果表明,在高温高压腐蚀环境下随着CO2分压从低到高,其表面点蚀坑的深度和直径均无明显变化,而点蚀速率则出现逐渐减小的趋势;其腐蚀产物膜由Cr(OH)3、FeCO3和CaCO3共同组成,且随着CO2分压的升高Cr的富集量逐渐增加;在电化学测试中,随着CO2分压的不断升高,5Cr套管钢表现出半钝化特征,产物膜逐渐增厚且致密,且极化电阻逐渐增大,阳极反应受到抑制,电化学反应阻力增大,其抗局部腐蚀能力不断提高.

通过浸泡腐蚀实验与高温高压电化学测试,研究了 J55钢在1.0 MPa CO2、0.3 MPa H2S及1.0 MPaCO2+0.3 MPa H2S气体组分下的腐蚀特征,并采用XRD、SEM和EDS分析腐蚀产物膜组成与形貌.结果显示,溶液中气体组分为H2S及CO2+H2S下的腐蚀速率相近,其表面产物为FeS.在只含H2S气体时,J55钢的表面FeS产物膜致密;而在CO2氛围下J55钢的腐蚀速率最高,其产物为疏松、覆盖率较低的FeCO3.高温高压原位电化学测试显示,不含腐蚀气体时溶液介质对J55钢的腐蚀表现为阴极控制;加入H2S使腐蚀转为阳极控制,腐蚀电位明显升高;而CO2的加入能强化阴极控制效果,同时降低腐蚀电位;溶液中CO2与H2S共存时,CO2使FeS的成膜电位增加.EIS图显示,J55钢在不含腐蚀性气体时极化电阻最大,仅含CO2时极化电阻最小,仅含H2S时出现高频容抗弧与低频容抗弧两个时间常数.

针对N80钢油套管在CO2/H2S共存环境中的腐蚀问题,利用失重法与电化学测试方法作对比分析,并利用扫描电子显微镜以及X射线衍射仪对浸泡腐蚀试验后的N80钢试样进行研究.结果显示,浸泡腐蚀试验结果与电化学测试结果一致,在单独CO2环境中,N80钢的自腐蚀电流与平均腐蚀速率最大,腐蚀最严重;在单独H2S环境中,N80钢试样腐蚀速率最小,自腐蚀电流最小;在PCO2/PH2 S=1:0.3时,主要以H2S腐蚀为主,但在表面发生局部产物膜剥落,此时的腐蚀速率高于纯H2S条件下的腐蚀速率.研究表明,在单独CO2环境中,腐蚀以阴极反应过程控制为主;在单独H2S环境中,腐蚀以阳极反应过程控制为主;在PCO2/PH2 S=1:0.3时,腐蚀以阴极反应过程控制为主.

叶片是保证高炉煤气余压回收装置(TRT)平稳运行的重要零部件,定期检修更换叶片非常有必要.在干式TRT运行过程中发现,叶根和榫槽咬合处的涂料发生粉化失效,针对现存问题,对市售涂料进行调研,筛选出可施工时间0.5～2 h,实干时间4 h以上,并且耐饱和NH4Cl腐蚀的密封涂料.通过理化性能测试、耐高温性试验、TG-DSC分析等方法,对于可用于此工况下的两种涂料进行可适用性评价.结果表明:高固含量有机硅涂料在高温下性能保持率较高,优于室温硫化的硅橡胶涂料.且高固含量有机硅涂料具有良好的流平性,能够达到密封防腐的效果,对基材起到保护作用.

针对Φ88.9 mm×6.45 mm L80-13Cr油管穿孔现象,采用宏观分析、化学成分分析、金相分析、力学性能测试及扫描电子显微镜、能谱仪等手段,对规格为Φ88.9 mm×6.45 mm的L80-13Cr马氏体不锈钢油管发生穿孔的原因进行了分析.结果表明:该油管材质的化学成分、显微组织及力学性能等未见异常,但内壁存在严重的均匀腐蚀以及孔蚀,腐蚀形貌呈苔地状,腐蚀产物及腐蚀坑内填充物主要为Fe3O4、FeOOH、FeCr2O4及CrOOH.因此穿孔的发生主要是由于油管内壁的水中存在溶解氧,导致油管发生了严重的均匀腐蚀及孔蚀,孔蚀处壁厚减少,导致油管穿孔.

为了研究影响Q245R钢硫化物应力腐蚀开裂的主要原因,通过拉伸试验、宏观形貌观察、显微组织分析、能谱分析等手段研究其断口及表面处的腐蚀产物,并分析其腐蚀机理.结果表明:Q245R钢在H2S环境中发生开裂的类型主要是SSC,开裂的主要原因是其存在明显的带状组织,氢原子在带状组织的两种组织界面处与硫化物夹杂处聚集,产生氢压,形成微裂纹,致使最终开裂.Q245R钢断口符合应力腐蚀开裂断口特征且存在明显的带状组织二次裂纹,在二次裂纹的间隙中存在FeS晶体.

燃煤锅炉水冷壁管发生腐蚀会影响锅炉的使用寿命,缩短其使用周期从而影响经济效益,甚至影响锅炉的安全使用.为分析其发生腐蚀的原因,利用能谱和X射线衍射等技术对20#钢锅炉水冷壁管的腐蚀特征进行分析,研究腐蚀机理及类型,并提出相关防护与控制措施.研究结果表明:燃料煤中的硫元素、氯元素以及硫酸盐是管道外壁腐蚀的主要因素,此外,管道外壁的高温氧化也会促进其发生腐蚀.1号试样的腐蚀速率为0.1925mm/a,2号试样的腐蚀速率为0.3150mm/a.

通过高温高压腐蚀模拟试验、EDS、SEM、XPS等分析方法,研究了2507超级双相不锈钢在高温甲酸钾完井液环境中的腐蚀行为.结果 表明:随着温度的升高,2507超级双相钢的均匀腐蚀速率增加,从200℃时的0.0002 mm/a增加到240℃的0.8587 mm/a.温度为220℃和240℃时,2507超级双相钢在完井液中发生选择性腐蚀.XPS检测结果表明,试样表面生成以Fe、Cr、Ni的氧化物和氢氧化物为主的腐蚀产物膜.

针对油田酸化作业过程中出现油套管腐蚀的问题,采用失重法和电化学测试方法研究了超级13Cr油套管在油田残酸中的腐蚀行为.结果表明:超级13Cr不锈钢在180℃、总压10 MPa的残酸腐蚀环境中为中度腐蚀,以均匀腐蚀为主.超级13Cr不锈钢的阳极极化曲线无钝化区,腐蚀过程为阴极过程控制,随温度升高,自腐蚀电位负移,腐蚀驱动力增大.电化学阻抗(EIS)测试表明,随温度升高,极化电阻减小,电化学腐蚀动力学阻滞性减弱.

Multicomponent reactive transport modeling is a powerful tool for the comprehensive analysis of coupled hydraulic and biochemical processes. The performance of the simulation model depends on the accuracy of related model parameters whose values are usually difficult to determine from direct measurements. In this situation, estimates of these uncertain parameters can be obtained by solving inverse problems. In this study, an efficient data assimilation method, the iterative local updating ensemble smoother (ILUES), is employed for the joint estimation of hydraulic parameters, biochemical parameters and contaminant source characteristics in the sequential biodegradation process of tetrachloroethene (PCE). In the framework of the ILUES algorithm, parameter estimation is realized by updating local ensemble with the iterative ensemble smoother (IES). To better explore the parameter space, the original ILUES algorithm is modified by determining the local ensemble partly with a linear ranking selection scheme. Numerical case studies based on the sequential biodegradation of PCE are then used to evaluate the performance of the ILUES algorithm. The results show that the ILUES algorithm is able to achieve an accurate joint estimation of related model parameters in the reactive transport model.

针对钛合金在苛刻油田环境中的适用性,通过模拟腐蚀失重实验以及电化学测试分析,研究了TC4钛合金在高温高压完井液中的抗腐蚀及电化学腐蚀行为.结果表明,在总压为10 MPa,密度为1.4 g/cm3的甲酸钾完井液环境中经过360 h腐蚀,TC4钛合金有较高的腐蚀速率,其抗腐蚀性能较差,在210℃时,腐蚀速率达0.1361 mm/a.TC4钛合金阳极极化曲线均有钝化区,随温度升高,自腐蚀电流密度增大,腐蚀倾向性增大.电化学阻抗谱有明显的容弧特征,电荷转移电阻随温度升高减小很快,钝化膜的保护性减弱,表明TC4钛合金在高温高压甲酸钾完井液中的抗腐蚀性逐渐降低.

针对油气集输管线在CO2和含高浓度的Cl-地层水环境中易发生腐蚀失效的问题,通过腐蚀失重试验和电化学测试分析,研究了2205双相不锈钢在高分压CO2+高矿化度+高浓度Cl-地层水集输管线环境中的腐蚀行为.结果表明:在模拟油田集输管线环境中,升温引起的2205双相不锈钢的均匀腐蚀速率基本不变,整体表现为轻度腐蚀,但由于Cl-的存在,2205双相钢在50℃和70℃时出现明显的点蚀坑形貌;2205双相钢在3种测试温度下的阳极极化曲线存在明显的钝化区,随着温度的升高,2205双相钢的点蚀电位先升高、再下降,在30～50℃,存在一个临界点蚀温度CPT;交流阻抗图谱在50℃和70℃分别表现出了点蚀诱导期和点蚀发展期的特征.