The Experts below are selected from a list of 372 Experts worldwide ranked by ideXlab platform
Wei Ke - One of the best experts on this subject based on the ideXlab platform.
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high temperature Naphthenic Acid Corrosion and sulphidic Corrosion of q235 and 5cr1 2mo steels in synthetic refining media
Corrosion Science, 2006Co-Authors: D. R. Qu, H. M. Jing, Yingkui Zheng, Wei KeAbstract:The Corrosion of Q235 and 5Crl/2Mo steels in synthetic refining media containing Naphthenic Acid and/or sulphur compounds was studied to evaluate Naphthenic Acid Corrosion (NAC), sulphidic Corrosion (SC), and their interaction. Corrosion dependencies on the test duration, temperature, total Acid number (TAN) and content of sulphur compound were assessed. Specimens after NAC and SC tests were characterized by SEM/EDX, and XRD. It is found that in liquid phase of media containing only Naphthenic Acid and at temperature about 230 degrees C, 5Crl/2Mo and Q235 steels have almost the same NAC rate, and above 230 degrees C, 5Crl/2Mo has a higher NAC rate than Q235 has due to the higher NAC activation energy (63.2 kJ mol(-1)) of 5Crl/2Mo than that of Q235 (54.0 U mol(-1)), indicating that increasing temperature accelerates NAC rate of 5Crl/2Mo more than that of Q235. In oil containing only dimethyl disulphide, the growth of SC film follows parabolic kinetics, and the film of Q235 grows faster than that of 5Crl/2Mo while SC rate of Q235 is higher than that of 5Crl/2Mo. In oil containing both Naphthenic Acid and dimethyl disulphide, 5Crl/2Mo has a lower Corrosion rate than Q235 has. On the basis of "Naphthenic Acid Corrosion index" (NACI), the benefits of 5Crl/2Mo over Q235 should ascribe to that the pseudo-passive film for 5Crl/2Mo has better NAC resistance than that for Q235. This is close related to the existing of additional chromium sulphide (Cr5S8) on the pseudo-passive film of 5Crl/2Mo, in contrast with the pyrrhotite (Fe7S8) and troilite (FeS) on the film of Q235. (c) 2005 Elsevier Ltd. All rights reserved.
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High temperature Naphthenic Acid Corrosion and sulphidic Corrosion of Q235 and 5Cr1/2Mo steels in synthetic refining media
Corrosion Science, 2006Co-Authors: D. R. Qu, H. M. Jing, Yingkui Zheng, Wei KeAbstract:The Corrosion of Q235 and 5Crl/2Mo steels in synthetic refining media containing Naphthenic Acid and/or sulphur compounds was studied to evaluate Naphthenic Acid Corrosion (NAC), sulphidic Corrosion (SC), and their interaction. Corrosion dependencies on the test duration, temperature, total Acid number (TAN) and content of sulphur compound were assessed. Specimens after NAC and SC tests were characterized by SEM/EDX, and XRD. It is found that in liquid phase of media containing only Naphthenic Acid and at temperature about 230 degrees C, 5Crl/2Mo and Q235 steels have almost the same NAC rate, and above 230 degrees C, 5Crl/2Mo has a higher NAC rate than Q235 has due to the higher NAC activation energy (63.2 kJ mol(-1)) of 5Crl/2Mo than that of Q235 (54.0 U mol(-1)), indicating that increasing temperature accelerates NAC rate of 5Crl/2Mo more than that of Q235. In oil containing only dimethyl disulphide, the growth of SC film follows parabolic kinetics, and the film of Q235 grows faster than that of 5Crl/2Mo while SC rate of Q235 is higher than that of 5Crl/2Mo. In oil containing both Naphthenic Acid and dimethyl disulphide, 5Crl/2Mo has a lower Corrosion rate than Q235 has. On the basis of "Naphthenic Acid Corrosion index" (NACI), the benefits of 5Crl/2Mo over Q235 should ascribe to that the pseudo-passive film for 5Crl/2Mo has better NAC resistance than that for Q235. This is close related to the existing of additional chromium sulphide (Cr5S8) on the pseudo-passive film of 5Crl/2Mo, in contrast with the pyrrhotite (Fe7S8) and troilite (FeS) on the film of Q235. (c) 2005 Elsevier Ltd. All rights reserved.
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High temperature Naphthenic Acid Corrosion and sulphidic Corrosion of Q235 and 5Cr1/2Mo steels in synthetic refining media
Corrosion Science, 2006Co-Authors: D. R. Qu, Z. M. Yao, H. M. Jing, Y.-g. Zheng, Wei KeAbstract:The Corrosion of Q235 and 5Cr1/2Mo steels in synthetic refining media containing Naphthenic Acid and/or sulphur compounds was studied to evaluate Naphthenic Acid Corrosion (NAC), sulphidic Corrosion (SC), and their interaction. Corrosion dependencies on the test duration, temperature, total Acid number (TAN) and content of sulphur compound were assessed. Specimens after NAC and SC tests were characterized by SEM/EDX, and XRD. It is found that in liquid phase of media containing only Naphthenic Acid and at temperature about 230 ??C, 5Cr1/2Mo and Q235 steels have almost the same NAC rate, and above 230 ??C, 5Cr1/2Mo has a higher NAC rate than Q235 has due to the higher NAC activation energy (63.2 kJ mol-1) of 5Cr1/2Mo than that of Q235 (54.0 kJ mol-1), indicating that increasing temperature accelerates NAC rate of 5Cr1/2Mo more than that of Q235. In oil containing only dimethyl disulphide, the growth of SC film follows parabolic kinetics, and the film of Q235 grows faster than that of 5Cr1/2Mo while SC rate of Q235 is higher than that of 5Cr1/2Mo. In oil containing both Naphthenic Acid and dimethyl disulphide, 5Cr1/2Mo has a lower Corrosion rate than Q235 has. On the basis of "Naphthenic Acid Corrosion index" (NACI), the benefits of 5Cr1/2Mo over Q235 should ascribe to that the pseudo-passive film for 5Cr1/2Mo has better NAC resistance than that for Q235. This is close related to the existing of additional chromium sulphide (Cr5S8) on the pseudo-passive film of 5Cr1/2Mo, in contrast with the pyrrhotite (Fe7S8) and troilite (FeS) on the film of Q235. ?? 2005 Elsevier Ltd. All rights reserved.
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study on high temperature Naphthenic Acid Corrosion and erosion Corrosion of aluminized carbon steel
Journal of Materials Science, 2004Co-Authors: Xinqiang Wu, H. M. Jing, Yingkui Zheng, Wei KeAbstract:High-temperature Naphthenic Acid Corrosion (NAC) and erosion-Corrosion (NAEC) behaviors of pack-aluminized carbon steel have been investigated in laboratory to evaluate the resistance of aluminized layer to the NAC and NAEC. A field erosion-Corrosion test of 700 days was also performed in an oil refinery. Parallel tests were carried out for carbon steel. It was found that the aluminized steel exhibited a better NAC resistance only at early testing stage than the carbon steel in high total-Acid-number (TAN) environment. The NAC resistance degraded rapidly with increasing testing time, and became even worse than that of the carbon steel at final testing stage, accompanying a step-like or lamellar spallation in the aluminized layer. In low TAN environment, the aluminized steel exhibited a much better resistance to both the NAC and NAEC in comparison with the carbon steel. Similarly a good erosion-Corrosion resistance was found for the aluminized steel in actual oil-refining environment although relatively serious erosion-Corrosion attack simultaneously took place in the aluminized layer. Based on the above results, possible NAC and NAEC mechanisms for the aluminized steel are discussed.
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Resistance of Mo-bearing stainless steels and Mo-bearing stainless-steel coating to Naphthenic Acid Corrosion and erosion-Corrosion
Corrosion Science, 2004Co-Authors: X.j. Wu, Z. M. Yao, H. M. Jing, Y.-g. Zheng, Wei KeAbstract:Naphthenic Acid Corrosion (NAC) and erosion-Corrosion (NAEC) behavior of Mo-bearing (0-7.0 wt.%) stainless steels have been investigated in laboratory to evaluate the essential role of Mo on their NAC and NAEC resistance. The NAC and NAEC resistance of a high-velocity-oxygen-fuel (HVOF) thermal sprayed Mo-bearing stainless-steel coating was also investigated in both laboratory and an oil refinery. It was found that increasing the Mo content remarkably enhanced the NAC and NAEC resistance of stainless steels. The Mo-rich areas or phases in the steels played an importance role in resisting the NAEC. The HVOF coating showed excellent NAC and NAEC resistance in laboratory tests. The 700-day field test in an oil refinery revealed that the coating can effectively prevent the carbon-steel substrate from erosion-Corrosion during long-term exposure in oil-refining environment. The corresponding NAC and NAEC mechanisms of the stainless steels and the beneficial role of Mo were discussed by taking account of inherent susceptibility of metal elements to Corrosion, possible effects of Mo on surface films, and Mo-induced change in microstructure and microhardness. ?? 2003 Elsevier Ltd. All rights reserved.
D. R. Qu - One of the best experts on this subject based on the ideXlab platform.
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Naphthenic Acid Corrosion characteristic and Corrosion product film resistance of carbon steel and cr5mo low alloy steel in secondary vacuum gas oil
Corrosion Engineering Science and Technology, 2016Co-Authors: X L Zhang, D. R. Qu, Yougui Zheng, S L Jiang, X Jiang, Qixing YangAbstract:Although Naphthenic Acid Corrosion (NAC) has been studied for many years, the mechanism of NAC is not fully understood. The objective of this paper is to study high-temperature NAC in secondary vacuum gas oil of an industrial crude oil vacuum distillation tower. A high-temperature autoclave was applied to conduct high-temperature Corrosion test to investigate NAC behaviour of carbon steel and Cr5Mo low alloy steel at different sulphur contents and total Acid numbers (TAN). The result shows that the Corrosion rate of carbon steel and low alloy steel is high at low TAN and high TAN while it keeps at a low value at medium TAN. Corrosion product film on Cr5Mo low alloy steel surface is denser and more compact than that of carbon steel at high TAN. The chromium present in Cr5Mo low alloy steel plays an important role in NAC resistance by the formation of Cr7S8 film in the inner layer of the scale. Corrosion rates of the two steels in secondary vacuum gas oil are high at low TAN and high TAN, but low at medium ...
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Naphthenic Acid Corrosion of mild steel in the presence of sulfide scales formed in crude oil fractions at high temperature
CORROSION 2010, 2010Co-Authors: GM Bota, D. R. Qu, SM Nesic, H. Alan WolfAbstract:Increasing demand on the oil market has raised interest in oils with high Naphthenic Acid (NAP) concentration. These oils were previously considered of lower quality due to their corrosive character. Processing such oils at elevated temperatures encountered in refineries (300-350°C) may cause aggressive corrosive attack on the inside walls of equipment such as pipes and distillation towers. Naphthenic Acid Corrosion attack is a nonaqueous Corrosion process and can be retarded by sulfur containing compounds inherently present in crude oil fractions in the form of soluble sulfides. Although these sulfides can be corrosive as well, they can also form iron sulfide scale on the metal surfaces potentially offering a degree of protection against Naphthenic Acid attack. However the iron sulfide scales can be removed from metal surfaces under the combined effects of high velocity flow and NAP attack. This research project has focused on the role of iron sulfide scales formed in different crude oil fractions on samples made from mild as well as chromium containing steels. They were exposed to Naphthenic Acid attack under high flow rates at high temperature. © 2010 by NACE International.
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high temperature Naphthenic Acid Corrosion and sulphidic Corrosion of q235 and 5cr1 2mo steels in synthetic refining media
Corrosion Science, 2006Co-Authors: D. R. Qu, H. M. Jing, Yingkui Zheng, Wei KeAbstract:The Corrosion of Q235 and 5Crl/2Mo steels in synthetic refining media containing Naphthenic Acid and/or sulphur compounds was studied to evaluate Naphthenic Acid Corrosion (NAC), sulphidic Corrosion (SC), and their interaction. Corrosion dependencies on the test duration, temperature, total Acid number (TAN) and content of sulphur compound were assessed. Specimens after NAC and SC tests were characterized by SEM/EDX, and XRD. It is found that in liquid phase of media containing only Naphthenic Acid and at temperature about 230 degrees C, 5Crl/2Mo and Q235 steels have almost the same NAC rate, and above 230 degrees C, 5Crl/2Mo has a higher NAC rate than Q235 has due to the higher NAC activation energy (63.2 kJ mol(-1)) of 5Crl/2Mo than that of Q235 (54.0 U mol(-1)), indicating that increasing temperature accelerates NAC rate of 5Crl/2Mo more than that of Q235. In oil containing only dimethyl disulphide, the growth of SC film follows parabolic kinetics, and the film of Q235 grows faster than that of 5Crl/2Mo while SC rate of Q235 is higher than that of 5Crl/2Mo. In oil containing both Naphthenic Acid and dimethyl disulphide, 5Crl/2Mo has a lower Corrosion rate than Q235 has. On the basis of "Naphthenic Acid Corrosion index" (NACI), the benefits of 5Crl/2Mo over Q235 should ascribe to that the pseudo-passive film for 5Crl/2Mo has better NAC resistance than that for Q235. This is close related to the existing of additional chromium sulphide (Cr5S8) on the pseudo-passive film of 5Crl/2Mo, in contrast with the pyrrhotite (Fe7S8) and troilite (FeS) on the film of Q235. (c) 2005 Elsevier Ltd. All rights reserved.
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High temperature Naphthenic Acid Corrosion and sulphidic Corrosion of Q235 and 5Cr1/2Mo steels in synthetic refining media
Corrosion Science, 2006Co-Authors: D. R. Qu, H. M. Jing, Yingkui Zheng, Wei KeAbstract:The Corrosion of Q235 and 5Crl/2Mo steels in synthetic refining media containing Naphthenic Acid and/or sulphur compounds was studied to evaluate Naphthenic Acid Corrosion (NAC), sulphidic Corrosion (SC), and their interaction. Corrosion dependencies on the test duration, temperature, total Acid number (TAN) and content of sulphur compound were assessed. Specimens after NAC and SC tests were characterized by SEM/EDX, and XRD. It is found that in liquid phase of media containing only Naphthenic Acid and at temperature about 230 degrees C, 5Crl/2Mo and Q235 steels have almost the same NAC rate, and above 230 degrees C, 5Crl/2Mo has a higher NAC rate than Q235 has due to the higher NAC activation energy (63.2 kJ mol(-1)) of 5Crl/2Mo than that of Q235 (54.0 U mol(-1)), indicating that increasing temperature accelerates NAC rate of 5Crl/2Mo more than that of Q235. In oil containing only dimethyl disulphide, the growth of SC film follows parabolic kinetics, and the film of Q235 grows faster than that of 5Crl/2Mo while SC rate of Q235 is higher than that of 5Crl/2Mo. In oil containing both Naphthenic Acid and dimethyl disulphide, 5Crl/2Mo has a lower Corrosion rate than Q235 has. On the basis of "Naphthenic Acid Corrosion index" (NACI), the benefits of 5Crl/2Mo over Q235 should ascribe to that the pseudo-passive film for 5Crl/2Mo has better NAC resistance than that for Q235. This is close related to the existing of additional chromium sulphide (Cr5S8) on the pseudo-passive film of 5Crl/2Mo, in contrast with the pyrrhotite (Fe7S8) and troilite (FeS) on the film of Q235. (c) 2005 Elsevier Ltd. All rights reserved.
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High temperature Naphthenic Acid Corrosion and sulphidic Corrosion of Q235 and 5Cr1/2Mo steels in synthetic refining media
Corrosion Science, 2006Co-Authors: D. R. Qu, Z. M. Yao, H. M. Jing, Y.-g. Zheng, Wei KeAbstract:The Corrosion of Q235 and 5Cr1/2Mo steels in synthetic refining media containing Naphthenic Acid and/or sulphur compounds was studied to evaluate Naphthenic Acid Corrosion (NAC), sulphidic Corrosion (SC), and their interaction. Corrosion dependencies on the test duration, temperature, total Acid number (TAN) and content of sulphur compound were assessed. Specimens after NAC and SC tests were characterized by SEM/EDX, and XRD. It is found that in liquid phase of media containing only Naphthenic Acid and at temperature about 230 ??C, 5Cr1/2Mo and Q235 steels have almost the same NAC rate, and above 230 ??C, 5Cr1/2Mo has a higher NAC rate than Q235 has due to the higher NAC activation energy (63.2 kJ mol-1) of 5Cr1/2Mo than that of Q235 (54.0 kJ mol-1), indicating that increasing temperature accelerates NAC rate of 5Cr1/2Mo more than that of Q235. In oil containing only dimethyl disulphide, the growth of SC film follows parabolic kinetics, and the film of Q235 grows faster than that of 5Cr1/2Mo while SC rate of Q235 is higher than that of 5Cr1/2Mo. In oil containing both Naphthenic Acid and dimethyl disulphide, 5Cr1/2Mo has a lower Corrosion rate than Q235 has. On the basis of "Naphthenic Acid Corrosion index" (NACI), the benefits of 5Cr1/2Mo over Q235 should ascribe to that the pseudo-passive film for 5Cr1/2Mo has better NAC resistance than that for Q235. This is close related to the existing of additional chromium sulphide (Cr5S8) on the pseudo-passive film of 5Cr1/2Mo, in contrast with the pyrrhotite (Fe7S8) and troilite (FeS) on the film of Q235. ?? 2005 Elsevier Ltd. All rights reserved.
Gheorghe Bota - One of the best experts on this subject based on the ideXlab platform.
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Effect of Thiophenes on High-Temperature Corrosion by Sulfidation and Naphthenic Acids
Energy & Fuels, 2019Co-Authors: Winston K Robbins, Gheorghe BotaAbstract:Owing to the depletion of light sweet crude, high-temperature Corrosion by sulfidation and Naphthenic Acids in the oil phase has become one of major challenges for crude oil refineries. The Corrosion by model sulfur compounds and Naphthenic Acids has been extensively studied in laboratories, but the effect of thiophenes, which are widely present in crude oil, is often ignored due to their noncorrosiveness. In the current study, sulfidation and Naphthenic Acid Corrosion are studied in the presence/absence of two model thiophenes, dibenzothiophene and benzothiophene. It is found that thiophenes show an inhibitory effect on Naphthenic Acid Corrosion while not deterring sulfidation significantly. It was proposed that Naphthenic Acid may corrode the steel, generating iron naphthenates underneath an adsorption layer of thiophenes and producing magnetite.
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kinetic reaction modeling of Naphthenic Acid Corrosion and sulfidation in refineries a mechanistic model
Corrosion, 2018Co-Authors: Winston K Robbins, Gheorghe BotaAbstract:Corrosion by Naphthenic Acids and sulfur compounds has long plagued the refining industry, generating a large body of research and field literature. However, the Corrosion mechanism is not well und...
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Kinetic Reaction Modeling of Naphthenic Acid Corrosion and Sulfidation in Refineries—A Mechanistic Model
Corrosion, 2018Co-Authors: Winston K Robbins, Gheorghe BotaAbstract:Corrosion by Naphthenic Acids and sulfur compounds has long plagued the refining industry, generating a large body of research and field literature. However, the Corrosion mechanism is not well und...
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method for isolation and detection of ketones formed from high temperature Naphthenic Acid Corrosion
Energy & Fuels, 2017Co-Authors: Logan C Krajewski, Winston K Robbins, Gheorghe Bota, Vladislav V Lobodin, Alan G Marshall, Ryan P RodgersAbstract:Corrosion control at refineries remains a challenge because the mechanism of Naphthenic Acid (NAP) Corrosion is still not fully understood. The rate of NAP Corrosion does not correlate with Acidity (as measured by total Acid number); therefore, it has been suggested that a subset of NAP in petroleum fractions may be more corrosive than others. Because the primary Corrosion product (iron naphthenates) may thermally decompose to ketones at Corrosion temperatures (250–400 °C), ketones in Corrosion fluids could potentially be used to implicate specific problematic Acids in Corrosion tests. To that end, we have developed a method for isolating and characterizing ketones in Corrosion test solutions. Ketones from tests on palmitic and 4-cyclohexyl pentanoic Acids (C16H32O2 and C11H20O2) have been successfully isolated with a strong anion exchange solid-phase separation. Gas chromatography/mass spectrometry identifies ketones formed as a result of model Acid Corrosion. Fourier transform ion cyclotron resonance ma...
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characterization of magnetite scale formed in Naphthenic Acid Corrosion
JOM, 2017Co-Authors: Winston K Robbins, Gheorghe Bota, Srdjan NesicAbstract:Naphthenic Acid Corrosion (NAC) is one of the major concerns for Corrosion engineers in refineries. Iron sulfide (FeS) scales, formed from sulfur compound Corrosion, are traditionally considered to be semi-protective and lower NAG However, no relationship has been found between protectiveness and the characteristics of FeS scale. In this study, the corrosive processes of refineries have been probed with laboratory experiments using a model sulfur compound and petroleum-derived Naphthenic Acids. The morphology and composition of scales were analyzed with a combination of scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDS), and convergent beam electron diffraction (CBED). These high resolution microscopy techniques revealed the presence of an iron oxide (Fe3O4 or magnetite) layer on metal surfaces under a FeS layer in the scale. The presence of an oxide scale was correlated with the NAP Acid activity during the experiments. It is postulated that the formation of the Fe3O4 layer resulted from the decomposition of iron naphthenates at high temperatures.
H. M. Jing - One of the best experts on this subject based on the ideXlab platform.
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high temperature Naphthenic Acid Corrosion and sulphidic Corrosion of q235 and 5cr1 2mo steels in synthetic refining media
Corrosion Science, 2006Co-Authors: D. R. Qu, H. M. Jing, Yingkui Zheng, Wei KeAbstract:The Corrosion of Q235 and 5Crl/2Mo steels in synthetic refining media containing Naphthenic Acid and/or sulphur compounds was studied to evaluate Naphthenic Acid Corrosion (NAC), sulphidic Corrosion (SC), and their interaction. Corrosion dependencies on the test duration, temperature, total Acid number (TAN) and content of sulphur compound were assessed. Specimens after NAC and SC tests were characterized by SEM/EDX, and XRD. It is found that in liquid phase of media containing only Naphthenic Acid and at temperature about 230 degrees C, 5Crl/2Mo and Q235 steels have almost the same NAC rate, and above 230 degrees C, 5Crl/2Mo has a higher NAC rate than Q235 has due to the higher NAC activation energy (63.2 kJ mol(-1)) of 5Crl/2Mo than that of Q235 (54.0 U mol(-1)), indicating that increasing temperature accelerates NAC rate of 5Crl/2Mo more than that of Q235. In oil containing only dimethyl disulphide, the growth of SC film follows parabolic kinetics, and the film of Q235 grows faster than that of 5Crl/2Mo while SC rate of Q235 is higher than that of 5Crl/2Mo. In oil containing both Naphthenic Acid and dimethyl disulphide, 5Crl/2Mo has a lower Corrosion rate than Q235 has. On the basis of "Naphthenic Acid Corrosion index" (NACI), the benefits of 5Crl/2Mo over Q235 should ascribe to that the pseudo-passive film for 5Crl/2Mo has better NAC resistance than that for Q235. This is close related to the existing of additional chromium sulphide (Cr5S8) on the pseudo-passive film of 5Crl/2Mo, in contrast with the pyrrhotite (Fe7S8) and troilite (FeS) on the film of Q235. (c) 2005 Elsevier Ltd. All rights reserved.
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High temperature Naphthenic Acid Corrosion and sulphidic Corrosion of Q235 and 5Cr1/2Mo steels in synthetic refining media
Corrosion Science, 2006Co-Authors: D. R. Qu, H. M. Jing, Yingkui Zheng, Wei KeAbstract:The Corrosion of Q235 and 5Crl/2Mo steels in synthetic refining media containing Naphthenic Acid and/or sulphur compounds was studied to evaluate Naphthenic Acid Corrosion (NAC), sulphidic Corrosion (SC), and their interaction. Corrosion dependencies on the test duration, temperature, total Acid number (TAN) and content of sulphur compound were assessed. Specimens after NAC and SC tests were characterized by SEM/EDX, and XRD. It is found that in liquid phase of media containing only Naphthenic Acid and at temperature about 230 degrees C, 5Crl/2Mo and Q235 steels have almost the same NAC rate, and above 230 degrees C, 5Crl/2Mo has a higher NAC rate than Q235 has due to the higher NAC activation energy (63.2 kJ mol(-1)) of 5Crl/2Mo than that of Q235 (54.0 U mol(-1)), indicating that increasing temperature accelerates NAC rate of 5Crl/2Mo more than that of Q235. In oil containing only dimethyl disulphide, the growth of SC film follows parabolic kinetics, and the film of Q235 grows faster than that of 5Crl/2Mo while SC rate of Q235 is higher than that of 5Crl/2Mo. In oil containing both Naphthenic Acid and dimethyl disulphide, 5Crl/2Mo has a lower Corrosion rate than Q235 has. On the basis of "Naphthenic Acid Corrosion index" (NACI), the benefits of 5Crl/2Mo over Q235 should ascribe to that the pseudo-passive film for 5Crl/2Mo has better NAC resistance than that for Q235. This is close related to the existing of additional chromium sulphide (Cr5S8) on the pseudo-passive film of 5Crl/2Mo, in contrast with the pyrrhotite (Fe7S8) and troilite (FeS) on the film of Q235. (c) 2005 Elsevier Ltd. All rights reserved.
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High temperature Naphthenic Acid Corrosion and sulphidic Corrosion of Q235 and 5Cr1/2Mo steels in synthetic refining media
Corrosion Science, 2006Co-Authors: D. R. Qu, Z. M. Yao, H. M. Jing, Y.-g. Zheng, Wei KeAbstract:The Corrosion of Q235 and 5Cr1/2Mo steels in synthetic refining media containing Naphthenic Acid and/or sulphur compounds was studied to evaluate Naphthenic Acid Corrosion (NAC), sulphidic Corrosion (SC), and their interaction. Corrosion dependencies on the test duration, temperature, total Acid number (TAN) and content of sulphur compound were assessed. Specimens after NAC and SC tests were characterized by SEM/EDX, and XRD. It is found that in liquid phase of media containing only Naphthenic Acid and at temperature about 230 ??C, 5Cr1/2Mo and Q235 steels have almost the same NAC rate, and above 230 ??C, 5Cr1/2Mo has a higher NAC rate than Q235 has due to the higher NAC activation energy (63.2 kJ mol-1) of 5Cr1/2Mo than that of Q235 (54.0 kJ mol-1), indicating that increasing temperature accelerates NAC rate of 5Cr1/2Mo more than that of Q235. In oil containing only dimethyl disulphide, the growth of SC film follows parabolic kinetics, and the film of Q235 grows faster than that of 5Cr1/2Mo while SC rate of Q235 is higher than that of 5Cr1/2Mo. In oil containing both Naphthenic Acid and dimethyl disulphide, 5Cr1/2Mo has a lower Corrosion rate than Q235 has. On the basis of "Naphthenic Acid Corrosion index" (NACI), the benefits of 5Cr1/2Mo over Q235 should ascribe to that the pseudo-passive film for 5Cr1/2Mo has better NAC resistance than that for Q235. This is close related to the existing of additional chromium sulphide (Cr5S8) on the pseudo-passive film of 5Cr1/2Mo, in contrast with the pyrrhotite (Fe7S8) and troilite (FeS) on the film of Q235. ?? 2005 Elsevier Ltd. All rights reserved.
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resistance of mo bearing stainless steels and mo bearing stainless steel coating to Naphthenic Acid Corrosion and erosion Corrosion
Corrosion Science, 2004Co-Authors: Xinqiang Wu, H. M. Jing, Yingkui Zheng, W KeAbstract:Abstract Naphthenic Acid Corrosion (NAC) and erosion–Corrosion (NAEC) behavior of Mo-bearing (0–7.0 wt.%) stainless steels have been investigated in laboratory to evaluate the essential role of Mo on their NAC and NAEC resistance. The NAC and NAEC resistance of a high-velocity-oxygen-fuel (HVOF) thermal sprayed Mo-bearing stainless-steel coating was also investigated in both laboratory and an oil refinery. It was found that increasing the Mo content remarkably enhanced the NAC and NAEC resistance of stainless steels. The Mo-rich areas or phases in the steels played an importance role in resisting the NAEC. The HVOF coating showed excellent NAC and NAEC resistance in laboratory tests. The 700-day field test in an oil refinery revealed that the coating can effectively prevent the carbon-steel substrate from erosion–Corrosion during long-term exposure in oil-refining environment. The corresponding NAC and NAEC mechanisms of the stainless steels and the beneficial role of Mo were discussed by taking account of inherent susceptibility of metal elements to Corrosion, possible effects of Mo on surface films, and Mo-induced change in microstructure and microhardness.
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study on high temperature Naphthenic Acid Corrosion and erosion Corrosion of aluminized carbon steel
Journal of Materials Science, 2004Co-Authors: Xinqiang Wu, H. M. Jing, Yingkui Zheng, Wei KeAbstract:High-temperature Naphthenic Acid Corrosion (NAC) and erosion-Corrosion (NAEC) behaviors of pack-aluminized carbon steel have been investigated in laboratory to evaluate the resistance of aluminized layer to the NAC and NAEC. A field erosion-Corrosion test of 700 days was also performed in an oil refinery. Parallel tests were carried out for carbon steel. It was found that the aluminized steel exhibited a better NAC resistance only at early testing stage than the carbon steel in high total-Acid-number (TAN) environment. The NAC resistance degraded rapidly with increasing testing time, and became even worse than that of the carbon steel at final testing stage, accompanying a step-like or lamellar spallation in the aluminized layer. In low TAN environment, the aluminized steel exhibited a much better resistance to both the NAC and NAEC in comparison with the carbon steel. Similarly a good erosion-Corrosion resistance was found for the aluminized steel in actual oil-refining environment although relatively serious erosion-Corrosion attack simultaneously took place in the aluminized layer. Based on the above results, possible NAC and NAEC mechanisms for the aluminized steel are discussed.
Z Y Jiang - One of the best experts on this subject based on the ideXlab platform.
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synergy effect of Naphthenic Acid Corrosion and sulfur Corrosion in crude oil distillation unit
Applied Surface Science, 2012Co-Authors: B. S. Huang, D. H. Sang, Z Y JiangAbstract:Abstract The synergy effect of Naphthenic Acid Corrosion and sulfur Corrosion at high temperature in crude oil distillation unit was studied using Q235 carbon-manganese steel and 316 stainless steel. The Corrosion of Q235 and 316 in Corrosion media containing sulfur and/or Naphthenic Acid at 280 °C was investigated by weight loss, scanning electron microscope (SEM), EDS and X-ray diffractometer (XRD) analysis. The results showed that in Corrosion media containing only sulfur, the Corrosion rate of Q235 and 316 first increased and then decreased with the increase of sulfur content. In Corrosion media containing Naphthenic Acid and sulfur, with the variations of Acid value or sulfur content, the synergy effect of Naphthenic Acid Corrosion and sulfur Corrosion has a great influence on the Corrosion rate of Q235 and 316. It was indicated that the sulfur accelerated Naphthenic Acid Corrosion below a certain sulfur content but prevented Naphthenic Acid Corrosion above that. The Corrosion products on two steels after exposure to Corrosion media were investigated. The stable Cr5S8 phases detected in the Corrosion products film of 316 were considered as the reason why 316 has greater Corrosion resistance to that of Q235.
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Synergy effect of Naphthenic Acid Corrosion and sulfur Corrosion in crude oil distillation unit
Applied Surface Science, 2012Co-Authors: B. S. Huang, W. F. Yin, D. H. Sang, Z Y JiangAbstract:The synergy effect of Naphthenic Acid Corrosion and sulfur Corrosion at high temperature in crude oil distillation unit was studied using Q235 carbon-manganese steel and 316 stainless steel. The Corrosion of Q235 and 316 in Corrosion media containing sulfur and/or Naphthenic Acid at 280 °C was investigated by weight loss, scanning electron microscope (SEM), EDS and X-ray diffractometer (XRD) analysis. The results showed that in Corrosion media containing only sulfur, the Corrosion rate of Q235 and 316 first increased and then decreased with the increase of sulfur content. In Corrosion media containing Naphthenic Acid and sulfur, with the variations of Acid value or sulfur content, the synergy effect of Naphthenic Acid Corrosion and sulfur Corrosion has a great influence on the Corrosion rate of Q235 and 316. It was indicated that the sulfur accelerated Naphthenic Acid Corrosion below a certain sulfur content but prevented Naphthenic Acid Corrosion above that. The Corrosion products on two steels after exposure to Corrosion media were investigated. The stable Cr 5S 8 phases detected in the Corrosion products film of 316 were considered as the reason why 316 has greater Corrosion resistance to that of Q235. © 2012 Elsevier B.V. All rights reserved.
