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1.
In this work, corrosion and localized corrosion behavior of X65 pipeline steel were studied in a simulated, CO2-saturated oilfield formation water by various electrochemical measurement techniques, including electrochemical impedance spectroscopy (EIS), potentiodynamic polarization curves, galvanic current and localized EIS (LEIS). The morphology and composition of the formed corrosion scale were characterized by scanning electron microscopy and energy-dispersive X-ray analysis. A conceptual model was developed to illustrate the occurrence of localized corrosion of the steel under scale. Both galvanic current and LEIS measurements showed that a galvanic effect existed between the bare steel and the scale-covered region. The scale-covered region served as cathode and the bare steel site as the anode. The big cathode vs. small anode geometry accelerated the local corrosion reaction. At an elevated temperature, a compact, crystalline scale was formed on the steel surface, enhancing the galvanic effect. Moreover, the stability of the scale was increased with time, and localized corrosion of the steel under scale experienced mechanistic changes with time. 相似文献
2.
The corrosion behavior of mild steel in CO2-saturated 5% NaCl solution with N-[2-[(2-aminoethyl) amino] ethyl]-9-octadecenamide corrosion inhibitor at 25 °C has been studied by using potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) and Polarization Modulation Infrared Reflection Absorption Spectroscopy (PM-IRRAS) measurements. Both potentiodynamic polarization and EIS measurements reveal that this amido-amine precursor inhibits the carbon steel corrosion and the inhibition efficiency increases with increasing the inhibitor concentration. The corrosion inhibitor exhibits high corrosion efficiencies as a mixed-type inhibitor, with a predominant influence on the anode process. The organic inhibitor acts blocking surface sites at low concentrations and by modifying the adsorption mechanism forming a protective barrier against corrosive ions at high concentrations. EIS results show that the mechanism of its corrosion inhibition at concentrations higher than 0.82 × 10−5 M is by forming a protective bilayer with small pore sizes that hinders the passage of the reactive species. PM-IRRAS measurements demonstrate that the inhibitor is chemisorbed to surface steel. Therefore, its spectrum reveals that the inhibitor monolayer has an amorphous structure. 相似文献
3.
The corrosion behaviour of X 65 carbon steel in the presence of acetic acid in N2- and CO2-saturated systems has been investigated using electrochemical techniques. The presence of acetic acid does not influence
the anodic reaction but strongly accelerates the cathodic reaction. The cathodic reaction and consequently the corrosion rate
of mild steel in the CO2-saturated system increase with increase in acetic acid concentration and temperature. From the values of the apparent activation
energies, the corrosion reaction in the absence of acetic acid was found to be under mixed interfacial reaction/diffusion
control while interfacial reaction control dominates in the presence of acetic acid. The reduction of adsorbed undissociated
acetic acid on the metal surface is proposed as the key species primarily responsible for accelerated corrosion rate at all
temperatures. 相似文献
4.
5.
The performance of 1-[(2-hydroxyethyl) amino]-2-(salicylideneamino)ethane (HAS) as a corrosion inhibitor for carbon steel in CO2-saturated 3.0% NaCl solution under aerated and deaerated conditions was studied using weight loss and potentiodynamic polarization methods at different temperatures. The results obtained show that in aerated environment, HAS acts as an effective corrosion inhibitor for carbon steel in CO2-saturated brine solution and accelerate corrosion under deaerated condition. Inhibition efficiency (IE%) increased with increase in HAS concentration but decreased with increase in temperature. Corrosion inhibition action was via the adsorption of HAS on the metal’s surface which follows the Langmuir adsorption isotherm model. Polarization curves indicate that HAS functions as a mixed-type inhibitor. 相似文献
6.
The objective of this study is to evaluate the effect of low-level hydrogen sulfide (H2S) on carbon dioxide (CO2) corrosion of carbon steel in acidic solutions, and to investigate the mechanism of iron sulfide scale formation in CO2/H2S environments. Corrosion tests were conducted using 1018 carbon steel in 1 wt.% NaCl solution (25 °C) at pH of 3 and 4, and under atmospheric pressure. The test solution was saturated with flowing gases that change with increasing time from CO2 (stage 1) to CO2/100 ppm H2S (stage 2) and back to CO2 (stage 3). Corrosion rate and behavior were investigated using linear polarization resistance (LPR) technique. Electrochemical impedance spectroscopy (EIS) and potentiodynamic tests were performed at the end of each stage. The morphology and compositions of surface corrosion products were analyzed using scanning electron microscopy (SEM)/energy dispersive spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS). The results showed that the addition of 100 ppm H2S to CO2 induced rapid reduction in the corrosion rate at both pHs 3 and 4. This H2S inhibition effect is attributed to the formation of thin FeS film (tarnish) on the steel surface that suppressed the anodic dissolution reaction. The study results suggested that the precipitation of iron sulfide as well as iron carbonate film is possible in the acidic solutions due to the local supersaturation in regions immediately above the steel surface, and these films provide corrosion protection in the acidic solutions. 相似文献
7.
Scanning electron microscopy, X-ray diffraction and electrochemical measurement technique were applied to investigate the corrosion of SM 80SS tube steel in stimulant solution with carbon dioxide (CO2) and hydrogen sulfide (H2S) at variable conditions of PCO2/PH2S and temperature. The results suggest that there exists a synergism of sweet corrosion and sour corrosion on the steel surface, corrosion attack increases in the initial stage and then decrease with the increase of PCO2 or PH2S; serious corrosion occurs in the PCO2/PH2S ranged from 31 to 520. In addition, the fitted parabola function equation Y = 0.47873 + 0.04014X - (3.23788E−5)X2 is established, and the most serious corrosion is 600 for PCO2/PH2S. Under the moderate contents of PCO2 and PH2S, the corrosion scale consists of FeS0.9 and FeCO3; for relatively high PH2S, additive product FeS comes into being at high temperature such as T = 150 °C, product FeO(OH) is found in the corrosion scale. The H2S corrosion has a significant effect on the whole reaction process and iron sulfide is superior to precipitating on the steel surface compared with iron carbonate. In addition, the surface scales of iron sulfide almost act as a diffusion barrier and inhibit the corrosion by a coverage effect strongly depending on H2S concentration by EIS measurement. 相似文献
8.
Yong XiangZhe Wang Chao XuChengchuan Zhou Zheng LiWeidou Ni 《The Journal of Supercritical Fluids》2011,58(2):286-294
The corrosion behavior of X70 steel and iron in water-saturated supercritical CO2 mixed with SO2 was investigated using weight-loss measurements. As a comparison, the instantaneous corrosion rate in the early stages for iron in the same corrosion environment was measured by resistance relaxation method. Surface analyzes using SEM/EDS, XRD and XPS were applied to study the morphology and chemical composition of the corroded sample surface. Weight-loss method results showed that the corrosion rate of X70 steel samples increased with SO2 concentration, while the corrosion rate increased before decreasing with SO2 concentration for iron sample. Comparing resistance relaxation method results with weight-loss method results, it is found that the instantaneous corrosion rate of iron is much higher than the uniform corrosion rate of the iron tablet specimens which are covered with thick corrosion product films after a long period of corrosion. The corrosion product films were mainly composed of FeSO4 and FeSO3 hydrates. The possible reaction mechanism under such environment was also analyzed, and the electrochemical reaction between the dissolved SO2 in the condensed water film with iron is the critical reaction step. 相似文献
9.
Priya Kumari Paul Vandana Saraswat 《Journal of Adhesion Science and Technology》2019,33(12):1275-1293
The Chromene derivatives having heteroatoms as active sites were investigated for scaling downthe corrosion process in mild steel (MS). The effectiveness of the inhibitors was monitored by gravimetric potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) methods. Observations suggested that the mechanism of inhibition is mainly due to the adsorption of the inhibitor molecules on the MS surface. Adsorption of both inhibitors follows the Langmuir adsorption isotherm. Tafel curve shows that both inhibitors act as mixed type inhibitor. Morphological studies were done by FESEM and AFM instruments. These images indicated the formation of a protective layer on the MS surface which slows down the process of corrosion. DFT calculation provides the valuable quantum chemical parameters for both inhibitors which are supportive of the results obtained from gravimetric and EIS methods. 相似文献
10.
S. Sathiyanarayanan 《Electrochimica acta》2007,52(5):2068-2074
Organic coating strategies for corrosion protection with inherently conducting polymers have become important because of restriction on the use of heavy metals and chromates in coatings due to their environmental problems. This work presents the synthesis of polyaniline-TiO2 composites (PTC) and the corrosion protection behaviour of PTC containing coating on steel. PTC was prepared by chemical oxidation of aniline and TiO2 by ammonium persulfate in phosphoric acid medium. The PTC was characterized by FTIR, XRD and SEM techniques. Suitable coating with PTC was formed on steel using acrylic resin. Using electrochemical impedance spectroscopy, the PTC containing coating's behaviour in 3% NaCl immersion test and salt spray test has been found out. Results indicate that the coating containing PTC is able to maintain the potential of steel in passive region due to its redox property. The resistance of the coating containing PTC was more than 107 Ω cm2 in 3% NaCl solution after 60 days and 109 Ω cm2 in the salt spray test of 35 days. But the resistance of the TiO2 containing coating was found to be less than 104 Ω cm2 in both the cases. The high performance of PTC containing coating is attributed to the passivation of steel by polyaniline. 相似文献
11.
The corrosion inhibition of mild steel in 1 mol·L?1 hydrochloric acid by N-methyl-2-(2-nitrobenzylidene) hydrazine carbothioamide (MNBHC) was studied using weight loss and electrochemical studies. Results obtained indicate that the inhibitor is effective in hydrochloric acid medium and the efficiency decreases with increase in temperature. Added halide additives improve the efficiency of the inhibitor. The AC impedance studies reveal that the process of inhibition is through charge transfer. Polarization studies indicate the mixed nature of the in-hibitor. From the thermodynamic, spectral and surface analyses the nature of adsorption has been found out. The adsorption of the inhibitor on mild steel follows the Langmuir isotherm. 相似文献
12.
Ki-Don Sung Jin-Suk Lee Chul-Seung Shin Soon-Chul Park 《Korean Journal of Chemical Engineering》1998,15(4):449-450
A fresh water microalga, which has tolerance to high concentrations of CO2, was isolated. The KR-1 strain was identified as a genusChlorella. ThoughChlorella KR-1 showed maximum growth at 10 % (v/v) CO2, the strain showed a good growth rate up to 50 % (v/v) CO2. The results indicated the feasibility of the KR-1 strain for massive cultivation using condensed stack gases. 相似文献
13.
油气田CO2/H2S共存腐蚀与缓蚀技术研究进展 总被引:3,自引:0,他引:3
CO2/H2S是油气田采集、运输、处理过程中主要的腐蚀介质,由其引起的管道设备的腐蚀问题变得越来越严重,腐蚀和防腐已经成为研究热点。分别对近年来国内外开展的有关CO2和H2S共存腐蚀及缓蚀技术的研究进行综述。CO2/H2S共存腐蚀研究主要依靠试验手段,但目前的研究结果有很大的离散性,根据不同的试验条件会产生不同的研究结果。分压比是国内外大多数学者研究CO2/H2S腐蚀规律的切入点,但关于两者主导腐蚀的分压比界限划分现有研究存有争议。缓蚀技术研究讨论了缓蚀剂作用机理,评述了抑制CO2/H2S共存腐蚀常用的酰胺类、咪唑啉衍生物类、季铵盐类和Schiff碱类缓性剂在国内外的研究与应用现状,展望了这一领域的研究前景及发展方向。 相似文献
14.
CO2 corrosion of carbon steel pipelines in the presence of acetic acid was studied using artificial pit electrode assembly. The potential difference and the coupling current between the small attack and the outer large surface were monitored by means of a zero resistance ammeter (ZRA). The results give strong and complementary evidence about the major role of acetic acid in the growth mechanism of localized attacks in CO2 corrosion. Pits seem to propagate and stifle mainly according to counteracting depletion effects of respectively acetic acid and CO2. It is also shown that the purely ohmic drop is not the only factor contributing to the stifling of localized corrosion attacks in systems like those of top of line corrosion. On the basis of the obtained results, a complete scenario was therefore proposed for the morphological trend of localized attacks, which is in good agreement with field observations. 相似文献
15.
An environment friendly inhibitor, chitosan thiophene carboxaldehyde Schiff base, was synthesized by a condensation reaction of the carbonyl group of thiophene 2‐carboxaldehyde and free amino groups of chitosan. The chitosan Schiff base was characterized by UV spectroscopy, Fourier transform IR spectroscopy, elemental analysis and thermal analysis. The surface morphology of the Schiff base derivative was examined by SEM. Gravimetric and electrochemical techniques were used to explore the behaviour of the chitosan thiophene derivative as a corrosion inhibitor for mild steel in an acidic environment. The effects of inhibitor concentration, exposure time and temperature were investigated. The chitosan Schiff base showed a good inhibition performance of 92% inhibition efficiency at room temperature for 12 h of immersion in a weight loss experiment. The electrochemical results showed that the chitosan derivative acts as an effective mixed type inhibitor. The adsorption of the inhibitor followed the Temkin isotherm model. SEM and AFM techniques were used to characterize the protective layer formed on the mild steel substrate. © 2016 Society of Chemical Industry 相似文献
16.
Low Temperature Liquid State Synthesis of Lithium Zirconate and its Characteristics as a CO2 Sorbent
《分离科学与技术》2012,47(2):283-296
Abstract In this study, a new preparation method providing greatly improved CO2 sorption is introduced. Li2ZrO3 sorbent was prepared by low temperature co‐precipitation and compared in CO2 sorption performance with a sorbent prepared by the conventional high temperature solid‐state reaction method. The two sorbents were characterized using scanning electron microscopy, X‐ray diffraction and thermo‐gravimetric analysis. The Li2ZrO3 powder prepared by the relatively simple co‐precipitation method showed significantly better performance than the one prepared by solid‐state reaction with respect to both kinetics and CO2 sorption capacity. Extensive study of the powder prepared by co‐precipitation has been performed at various conditions. 相似文献
17.
Bishweshwar Pant 《Chemical Engineering Communications》2020,207(5):688-695
AbstractIn this work, a growth of Ag2CO3-TiO2 NPs over GO sheets and reduction of GO were simultaneously achieved by the hydrothermal process at 130 °C for 4?h. The photocatalytic activity of the as-prepared Ag2CO3-TiO2 NPs decorated reduced graphene oxide (Ag2CO3-TiO2/rGO) composite was studied by the degradation of methylene blue (MB) solution under visible light irradiation. A remarkable enhancement in the photocatalytic activity of the TiO2 was achieved after sensitizing with Ag2CO3 and loading in rGO sheets which is attributed to the reduced charge recombination, enhanced dye adsorption, and the improvement in the light harvesting capacity of the composite. 相似文献
18.
Adsorption of carbon dioxide by hydrotalcites was investigated by using a gravimetric method at 450 ‡C. Hydrotalcites possessed
higher adsorption capacity of CO2 than other basic materials such as MgO and Al2O3. Two different preparation methods of hydrotalcite with varying Mg/Al ratio were employed to determine their effects on the
adsorption capacity of CO2. In addition, varying amounts of K2CO3 were impregnated on the hydrotalcite to further increase its adsorption capacity of CO2. The hydrotalcite prepared by the high supersaturation method with Mg/Al=2 showed the most favorable adsorption-desorption
pattern with high adsorption capacity of CO2. K2CO3 impregnation on the hydrotalcite increased the adsorption capacity of CO2 because it changed both the chemical and the physical properties of the hydrotalcite. The optimum amount of K2CO3 impregnation was 20 wt%. The hydrotalcite prepared by the high supersaturation method with Mg/Al=2 and 20 wt% K2CO3 impregnation has the highest adsorption capacity of CO2 with 0.77 mmol CO2/g at 450 ‡C and 800 mmHg. 相似文献
19.
The use of cerium salts as corrosion inhibitors for hot dip galvanized steel has been object of a numerous studies in the last few years. The role of cerium ions as corrosion inhibitors was proved: cerium is able to block the cathodic sites of the metal, forming insoluble hydroxides and oxides on the zinc surface. This fact leads to a dramatic decrease of the cathodic current densities and, therefore, to a reduction the overall corrosion processes. On the other hand, the potential of cerium oxides as corrosion inhibitors was also proposed. However, the real effectiveness of this kind of anticorrosive pigments has not been clarified yet.In this work cerium (IV) oxides are considered as corrosion inhibitors for galvanized steel. The corrosion inhibition mechanism of mechanically treated (milled) CeO2 alone and in combination with milled SiO2 nanoparticles was investigated. For this purpose milled CeO2, CeO2 and SiO2 milled together and milled SiO2 particles were studied as corrosion inhibitors in water solution. Therefore, the different mechanically treated particles were dispersed in 0.1 M NaCl solution to test their effectiveness as corrosion inhibitors for galvanized steel. The galvanized steel was immersed in the different solutions and the corrosion inhibition efficiency of the different particles was measured by means of electrochemical techniques. For this purpose, electrochemical impedance spectroscopy (EIS) measurements were carried out, monitoring the evolution of the corrosion processes occurring at the metal surface with the immersion time in the solution. The effect of the different pigments was also investigated by carrying out anodic and cathodic polarization measurements. The polarization curves were acquired under conditions of varied pH. The experimental measurements suggest that the mechanical treatment performed on the SiO2 and CeO2 particles promote the formation of an effective corrosion pigment. The tests evidence also the beneficial effect of the CeO2 milled particles when used in combination with the mechanically treated SiO2 particles. It was proved that in alkaline conditions the effect of the mechanically treated CeO2 and SiO2 particles is dramatically increased. 相似文献
20.
Saviour A. Umoren 《Journal of Adhesion Science and Technology》2016,30(17):1858-1879
The toxic nature of most organic and inorganic corrosion inhibitors has necessitated the search for corrosion inhibitors with an excellent environmental profile. The present work is focused on the widening utilization of plant extracts for metallic corrosion control and reports on the corrosion inhibition effect of mustard seed extract (MSE) for typical X60 pipeline steel in 2 M HCl and 1 M H2SO4 solutions. Gravimetric and electrochemical (electrochemical impedance spectroscopy, linear polarization resistance and potentiodynamic polarization) methods were employed. The effect of immersion time and temperature on the corrosion inhibition effect of the plant extract was also studied. Results obtained show that MSE inhibited the corrosion of steel in both media which was more pronounced in H2SO4 than in HCl environment. Inhibition efficiency increased with increase in the concentration of the extract but decreased with increase in temperature. The potentiodynamic polarization studies revealed that MSE functions as a mixed-type inhibitor. The corrosion inhibition is assumed to occur via adsorption of the components of the extract on the steel surface which was found to obey Langmuir adsorption isotherm model. The morphology of the corroding steel surface in the absence and presence of the MSE was visualized using scanning electron microscopy. 相似文献