Effects of alternating current interference on cathodic protection potential and its effectiveness for corrosion protection of pipelines

Kuang, Da; Cheng, Y. Frank

doi:10.1080/1478422x.2016.1175773

Cited by 22 publications

(16 citation statements)

References 21 publications

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“…Conversely at −1 V vs. SCE, AC shifts potential in the positive direction. Similar observations were reported by Kuang et al [53,54]: the DC potential of X65 steel in near-neutral pH bicarbonate solution is shifted negatively by AC at −0.85 V vs. CSE, but positively shifted by AC under the CP of −1 V vs. CSE (Figure 2). Nevertheless, differently to what can be expected, the potential variation reported is higher at smaller AC density (Figure 2b).…”

Section: Effect On DC Potential (Cathodic Protection Condition)supporting

confidence: 89%

AC Corrosion of Carbon Steel under Cathodic Protection Condition: Assessment, Criteria and Mechanism. A Review

2020

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Cathodic protection (CP), in combination with an insulating coating, is a preventative system to control corrosion of buried carbon steel pipes. The corrosion protection of coating defects is achieved by means of a cathodic polarization below the protection potential, namely −0.85 V vs. CSE (CSE, copper-copper sulfate reference electrode) for carbon steel in aerated soil. The presence of alternating current (AC) interference, induced by high-voltage power lines (HVPL) or AC-electrified railways, may represent a corrosion threat for coated carbon steel structures, although the potential protection criterion is matched. Nowadays, the protection criteria in the presence of AC, as well as AC corrosion mechanisms in CP condition, are still controversial and discussed. This paper deals with a narrative literature review, which includes selected journal articles, conference proceedings and grey literature, on the assessment, acceptable criteria and corrosion mechanism of carbon steel structures in CP condition with AC interference. The study shows that the assessment of AC corrosion likelihood should be based on the measurement of AC and DC (direct current) related parameters, namely AC voltage, AC and DC densities and potential measurements. Threshold values of the mentioned parameters are discussed. Overprotection (EIR-free < −1.2 V vs. CSE) is the most dangerous condition in the presence of AC: the combination of strong alkalization close to the coating defect due to the high CP current density and the action of AC interference provokes localized corrosion of carbon steel.

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Section: Effect On DC Potential (Cathodic Protection Condition)supporting

confidence: 89%

AC Corrosion of Carbon Steel under Cathodic Protection Condition: Assessment, Criteria and Mechanism. A Review

2020

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“…The high-strength steel is very sensitive to hydrogen embrittlement (Hardie et al, 2006), and X80 steel has been widely used in oil and gas pipelines (Liang et al, 2009;Lei and Shan, 2005;Feng et al, 2020). Alternating current (AC) interference corrosion is one of the main causes of corrosion failure of X80 pipeline steel (Zhu et al, 2014a;Fu and Cheng, 2012;Kuang and Cheng, 2017).…”

Section: Introductionmentioning

confidence: 99%

“…Research by Zhu et al (2014a) showed that AC interference exceeding 100░ A/m 2 in a high pH environment may generate hydrogen atoms and cause HIC, increasing the stress corrosion cracking sensitivity of X80 steel. Research by Fu and Cheng (2012) and Kuang and Cheng (2017) showed that AC interference affected the stability of X80 steel's cathodic protection potential, resulting in excessive cathodic protection and hydrogen evolution reaction. Research by Wan et al (2017a) showed that the negative half-wave current (NC) promoted the hydrogen evolution reaction of X80 steel and increased the stress corrosion cracking sensitivity.…”

Section: Introductionmentioning

confidence: 99%

Study on hydrogen permeation behavior of X80 steel under AC stray current interference

Wang¹,

Deng²,

Li³

et al. 2021

ACMM

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Purpose Alternating current (AC) corrosion is a type of corrosion that occurs in buried pipelines under AC stray current interference, which can increase the hydrogen embrittlement sensitivity of pipelines. However, rare research works have been conducted on the hydrogen permeability characteristics of pipeline steel under AC stray current interference. The purpose of this paper is to study hydrogen permeation behavior of X80 steel under AC stray current interference. Design/methodology/approach In this paper, the hydrogen permeation behavior of X80 steel under AC interference is studied by AC hydrogen charging experiment in a dual electrolytic cell. The relationship between hydrogen evolution rate and hydrogen permeation flux is studied using the gas collection method. The difference between AC hydrogen permeability and direct current (DC) hydrogen permeability is also discussed. Findings The anodic dissolution caused by AC corrosion promotes the chemical desorption reaction of the adsorbed hydrogen atoms on the surface, reducing the hydrogen atom absorption ratio by 70%. When the AC is smaller than 150░ A/m2, the hydrogen permeation process is controlled by the hydrogen atom generation rate, and the hydrogen permeation flux increases with the increase in hydrogen atom generation rate. When the AC exceeds 400░ A/m2, the hydrogen permeation process is controlled by the absorption ratio. The hydrogen permeation flux decreases with the decrease in the absorption ratio. Under AC interference, there is a maximum hydrogen permeation flux that linearly correlates to the H+ concentration in the solutions. Originality/value The high-strength steel is very sensitive to hydrogen embrittlement, and X80 steel has been widely used in oil and gas pipelines. To date, no research has been conducted on the hydrogen permeation behavior of pipeline steel under AC interference, and the hydrogen permeability characteristics of pipeline steel under AC interference are not clear. The research results of this paper are of great significance for ensuring the intrinsic safety of high-strength pipelines under AC stray current interference.

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“…Alternating current (AC) corrosion refers to the corrosion process that may occur under the action of AC stray current or AC induced voltage on pipeline steel even though the cathodic protection system existed. Typically, AC corrosion is the electrochemical corrosion reaction to promote pipeline failure (Hu et al, 2010;Fu and Cheng, 2010;Fu and Cheng, 2012;Kuang and Cheng, 2017). Because of burying crosswise or parallelly with high voltage transmission line and AC electrified railways, AC stray current will produce in the pipeline and outflow the pipeline through the coating defect, causing AC corrosion perforation (Mi, 2008).…”

Section: Introductionmentioning

confidence: 99%

Effect of AC interference on hydrogen evolution reaction of x80 steel

Zhou

Liu

et al. 2020

ACMM

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Purpose The purpose of this paper is to quantify the influence of alternating current (AC) interference on hydrogen evolution reaction of X80 steel. Design/methodology/approach The hydrogen evolution potential was obtained by cathodic potentiodynamic polarization curve. The instantaneous potential under AC interference was obtained by high-frequency acquisition with three-electrode system. Electrochemical impedance spectroscopy and Tafel polarization curves were used to study the influence mechanism of AC interference on instantaneous potential. Findings It was concluded that the hydrogen evolution reaction could occur on X80 steel under AC interference. There were critical AC current densities of about 100 to 200 A/m2, beyond which the cathode reaction of X80 steel changed from oxygen absorption to hydrogen evolution. Besides the pH value, the initial polarization potential EZ and impedance module of the steel/electrolyte interface under AC interference were also the factors that affected the critical AC densities in different solutions. Originality/value This research quantified the hydrogen evolution capacity of X80 steel under AC interference, which could be applied to clear the effect of AC interference on hydrogen evolution reaction.

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Effects of alternating current interference on cathodic protection potential and its effectiveness for corrosion protection of pipelines

Cited by 22 publications

References 21 publications

AC Corrosion of Carbon Steel under Cathodic Protection Condition: Assessment, Criteria and Mechanism. A Review

AC Corrosion of Carbon Steel under Cathodic Protection Condition: Assessment, Criteria and Mechanism. A Review

Study on hydrogen permeation behavior of X80 steel under AC stray current interference

Effect of AC interference on hydrogen evolution reaction of x80 steel

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