Carbon steel corrosion under anaerobic–aerobic cycling conditions in near-neutral pH saline solutions. Part 2: Corrosion mechanism

Hydrogen sulfide (H2S) is the most dangerous element which exists in oil and gas reservoir. H2S acidifies water which causes pitting corrosion to carbon steel pipelines. Corrosion reaction will increase fast when it combines with oxygen and carbon dioxide (CO2). Thus, they can significantly reduce service life of transportation pipelines and processing facilities in oil and gas industries. Understanding corrosion mechanism of H2S is crucial to study since many severe deterioration of carbon steels pipelines found in oil and gas industries facilities. To investigate H2S corrosion accurately, it requires studying physical, electrical and chemical properties of the environment. This paper concentrates, especially, on carbon steel corrosion caused by H2S gas. How this gas reacts with carbon steel in oil and gas reservoir is also discussed. This paper also reviews the developments of corrosion prediction software of H2S corrosion. The corrosion mechanism of H2S combined with CO2 gas is also in focused.

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THE EFFECT OF TANNIN ON CARBON STEEL CORROSION IN NITRIC ACID SOLUTIONS

Jurnal Teknologi Bahan dan Barang Teknik ◽

10.37209/jtbbt.v5i1.53 ◽

2015 ◽

Vol 5 (1) ◽

pp. 1

Author(s):

Anna Sonya Asoka ◽

Listiani Artha ◽

Isdiriayani Nurdin ◽

Hary Devianto

Keyword(s):

Nitric Acid ◽

Carbon Steel ◽

Acid Solution ◽

Corrosion Inhibitor ◽

Nitric Acid Solution ◽

Construction Material ◽

Steel Corrosion ◽

Corrosion Mechanism ◽

Acid Solutions ◽

Nitric Acid Solutions

Carbon steel is commonly used as construction material of processing equipment due to its strength, ease of fabrication, and low cost. Nevertheless, carbon steel is susceptible to corrosion by process fluid, like nitric acid. However, corrosion effect can be reduced by inhibitor addition. Tannin is one of carbon steel corrosion inhibitors in acidic solution. Tannin is an organic compound which has hidroxyl and carboxyl functional groups, decomposed easily, and non-toxic. The aim of this research is to determine the effectiveness of tannin as a corrosion inhibitor for carbon steel in nitric acid solutions. The corrosion rate is determined using the Tafel method, whereas the corrosion mechanism is predicted by cyclic voltammetry. The results showed that tannin is ineffective to inhibit carbon steel corrosion in nitric acid solution. The carbon steel corrosion reaction in nitric acid solution, with or without tannin addition, is reversible, involving single step oxidation-reduction reaction, resulting stable corrosion product, and not forming any passivation.Keywords: carbon steel, corrosion, inhibitor, nitric acid, tannin

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Effect of Additional Sulfide and Thiosulfate on Corrosion of Q235 Carbon Steel in Alkaline Solutions

International Journal of Corrosion ◽

10.1155/2016/8549312 ◽

2016 ◽

Vol 2016 ◽

pp. 1-8 ◽

Cited By ~ 2

Author(s):

Bian Li Quan ◽

Jun Qi Li ◽

Chao Yi Chen

Keyword(s):

Carbon Steel ◽

Photoelectron Spectroscopy ◽

Steel Corrosion ◽

Corrosion Products ◽

Alkaline Solutions ◽

Corrosion Mechanism ◽

Surface Cracks ◽

Weight Loss Method ◽

Q235 Carbon Steel ◽

Loss Method

This paper investigated the effect of additional sulfide and thiosulfate on Q235 carbon steel corrosion in alkaline solutions. Weight loss method, scanning electron microscopy (SEM) equipped with EDS, X-ray photoelectron spectroscopy (XPS), and electrochemical measurements were used in this study to show the corrosion behavior and electrochemistry of Q235 carbon steel. Results indicate that the synergistic corrosion rate of Q235 carbon steel in alkaline solution containing sulfide and thiosulfate is larger than that of sulfide and thiosulfate alone, which could be due to redox reaction of sulfide and thiosulfate. The surface cracks and pitting characteristics of the specimens after corrosion were carefully examined and the corrosion products film is flake grains and defective. The main corrosion products of specimen induced by S2−and S2O32-are FeS, FeS2, Fe3O4, and FeOOH. The present study shows that the corrosion mechanism of S2−and S2O32-is different for the corrosion of Q235 carbon steel.

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Corrosion behaviors of steels under supercritical CO2 conditions

Corrosion Reviews ◽

10.1515/corrrev-2014-0067 ◽

2015 ◽

Vol 33 (3-4) ◽

pp. 151-174 ◽

Cited By ~ 10

Author(s):

Liang Wei ◽

Yucheng Zhang ◽

Xiaolu Pang ◽

Kewei Gao

Keyword(s):

Carbon Steel ◽

Corrosion Rate ◽

Stainless Steels ◽

Steel Corrosion ◽

Carbon Steels ◽

Corrosion Mechanism ◽

Electrochemical Behaviors ◽

Structure Morphology ◽

Corrosion Behaviors ◽

Corrosion Scales

AbstractCarbon dioxide (CO2) corrosion at low partial pressure has been widely recognized, but research on supercritical CO2 (SC CO2) corrosion is very limited. By far, investigations on steel corrosion under SC CO2 conditions have mainly focused on the corrosion rate, structure, morphology, and composition of the corrosion scales as well as the electrochemical behaviors. It was found in aqueous SC CO2 environment, that the corrosion rate of carbon steel was very high, and even stainless steels (13Cr and high-alloy CrNi steels) were subjected to some corrosion. Inhibitor could reduce the corrosion rate of carbon steels and stainless steels, but none of the tested inhibitors could reduce the corrosion rate of carbon steel to an acceptable value. Impurities such as O2, SO2, and NO2 and their mixtures in SC CO2 increased the corrosion rate of carbon steel. However, the existing studies so far were very limited on the corrosion mechanism of steels in SC CO2 conditions. Thus, this paper first reviews the finding on the corrosion behaviors of steels under SC CO2 conditions, points out the shortcomings in the present investigations and finally looks forward to the research prospects on SC CO2 corrosion.

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The effect of aerobic corrosion on anaerobically-formed sulfide layers on carbon steel in dilute near-neutral pH saline solutions

Corrosion Science ◽

10.1016/j.corsci.2013.08.011 ◽

2013 ◽

Vol 77 ◽

pp. 257-264 ◽

Cited By ~ 4

Author(s):

B.W.A. Sherar ◽

P.G. Keech ◽

D.W. Shoesmith

Keyword(s):

Carbon Steel ◽

Neutral Ph ◽

Saline Solutions

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CORROSION CHARACTERIZATIONS OF CARBON STEEL IN CAI TAU RIVER WATER SYSTEM - VIET NAM

Vietnam Journal of Science and Technology ◽

10.15625/2525-2518/55/5b/12211 ◽

2018 ◽

Vol 55 (5B) ◽

pp. 66

Author(s):

T. K. N. Hoi

Keyword(s):

Carbon Steel ◽

River Water ◽

Surface Analysis ◽

Pitting Corrosion ◽

Electrochemical Techniques ◽

Water System ◽

Steel Corrosion ◽

Corrosion Mechanism ◽

Corrosion Properties ◽

Passive Behavior

Corrosion problem happens in Cai Tau river water system; however, the mechanism is still questionable, resulting in unsolved ways. Therefore, this study focuses on the corrosion characterizations of carbon steel in Cai Tau river water system to analyze the corrosion mechanism using advanced electrochemical techniques and surface analysis. Electrochemical results indicated that Cl‾ and SO42- ions shows a significant effect on corrosion of carbon steel, resulting in pitting corrosion. Whereas, carbon steel showed passive behavior when it immersed in solution containing CO32- ion. Furthermore, pH strongly affects the corrosion properties of carbon steel. It indicated that corrosion of carbon steel increased with a decrease of pH. Surface analysis was done to identify the surface area of the pitting corrosion of carbon steel. Corrosion rates, pitting and corrosion products were clearly observed and analyzed by optical microscopy and X-ray diffraction.

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