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Article
Publication date: 15 January 2019

Jun Wang, Zili Li, Gan Cui, JianGuo Liu, Chuanping Kong, Long Wang, Ge Gao and Jian Guo

The purpose of this paper is to study the corrosion behaviors of X70 steel under direct current (DC) interference at 0-1,200 A/m2 in simulated soil solution.

Abstract

Purpose

The purpose of this paper is to study the corrosion behaviors of X70 steel under direct current (DC) interference at 0-1,200 A/m2 in simulated soil solution.

Design/methodology/approach

The Tafel polarization curves of X70 steel under DC interference were tested using electrochemical method, the corrosion rate was calculated using weight-loss method and the change in steel surface was analyzed by optical microscopy.

Findings

The results showed that E-I polarization curves under 200-1,200 A/m2 interference were linear; with an increase in the DC density, the corrosion potential of X70 steel shifted positively, solution pH after the weight-loss tests increased and corrosion rate increased linearly. A mathematical relationship between polarization resistance Rp and current density was established. Corrosion morphology indicated that pitting corrosion and crevice corrosion occurred on the X70 steel under DC interference in simulated soil solution.

Originality/value

All tests were conducted at a relative higher DC density (200-1,200 A/m2). The linear fitting method is proposed to fit data of Tafel polarization curves under DC interference. This study provides guidelines for safe operation of X70 steel pipelines.

Details

Anti-Corrosion Methods and Materials, vol. 66 no. 3
Type: Research Article
ISSN: 0003-5599

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Article
Publication date: 17 December 2018

Ziqing Yang, Gan Cui, Zili Li and JianGuo Liu

In recent years, the demand for oil and gas pipelines has increased rapidly. Due to the restrictions of the pipeline routing, pipelines are generally laid in parallel or…

Abstract

Purpose

In recent years, the demand for oil and gas pipelines has increased rapidly. Due to the restrictions of the pipeline routing, pipelines are generally laid in parallel or in the same trench, which results in stray-current interference between the independent cathodic protection (CP) systems. The purpose of this paper is to study the interference between the long-distance parallel pipelines and to obtain the optimized operation for the CP systems.

Design/methodology/approach

In this study, first, the numerical model of parallel pipelines was established using the boundary element analysis software (BEASY). Second, the effects of horizontal distance between parallel pipelines, coating damage rate, soil conductivity and anode output current on the interference of parallel pipelines were studied. Finally, by varying the layout or the output currents of CP stations, an optimized operation scheme osf long-distance parallel pipelines was put forward.

Findings

Simulation results showed that with a decrease in soil conductivity or coating damage rate, the interference increased. Moreover, the interference decreased with an increase in horizontal distance between two parallel pipelines or a decrease in anode output current. It was found that there are three methods to reduce the interference between long-distance parallel pipelines: to reduce the output currents of CP stations, combined protection and to close part of the CP stations. Among them, to close part of CP stations was the optimized scheme because of the lowest operating and maintenance cost.

Originality/value

The optimized operation scheme proposed in this study can not only solve the interference between parallel pipelines but also provide guidance for the parallel pipelines to be built in the future. Reasonably arranging the cathodic protection stations using numerical simulation can avoid the interference in the cathodic protection systems, and reduce the construction cost.

Details

Anti-Corrosion Methods and Materials, vol. 66 no. 2
Type: Research Article
ISSN: 0003-5599

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Article
Publication date: 29 March 2021

Ailing Wang, Yong Deng, Kaihong Li, Wenlei Li, Dongliang Yu, Gan Cui, JianGuo Liu and Zili Li

Alternating current (AC) corrosion is a type of corrosion that occurs in buried pipelines under AC stray current interference, which can increase the hydrogen…

Abstract

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.

Details

Anti-Corrosion Methods and Materials, vol. 68 no. 2
Type: Research Article
ISSN: 0003-5599

Keywords

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Article
Publication date: 31 January 2020

JiaYu Zhou, Zili Li, JianGuo Liu, Xiao Xing, Gan Cui, ShouXin Zhang, Ran Cheng and YiShu Wang

The purpose of this paper is to quantify the influence of alternating current (AC) interference on hydrogen evolution reaction of X80 steel.

Abstract

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.

Details

Anti-Corrosion Methods and Materials, vol. 67 no. 2
Type: Research Article
ISSN: 0003-5599

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Article
Publication date: 3 September 2019

Qingmiao Ding, Zili Li, Tao Shen and Gan Cui

This paper aims to research the corrosion behavior of the metal under the disbonded coatings interfered with AC through electrochemical method.

Abstract

Purpose

This paper aims to research the corrosion behavior of the metal under the disbonded coatings interfered with AC through electrochemical method.

Design/methodology/approach

The corrosion behavior of the metal under disbond coating interfered with alternate stray current (AC) was studied by electrochemical methods using the rectangular coating disbonded simulator. The obtained data from electrode potential test, electrochemical impedance spectroscopy (EIS) and polarization curves in simulated soil solution indicated that under the natural corrosion condition, the self-corrosion potential and the corrosion current density of the metal at different depths under disbond coating had obviously changed if there was AC interference.

Findings

The self-corrosion potential of the metal at the same depths under disbond coating shifted negatively with the rising of the AC voltage. Under the condition of cathode polarization, there was still obvious potential gradient with the extension of the deep peeling of the coating gap, and the corrosion current density of the test points was minimum, and the protection effect was best when the cathode protection potential was −1.0 V. When the metal was applied with over-protection, the corrosion rate of the metal increased as AC stray current flowing through it increased.

Originality/value

This paper used the rectangular aperture device to study the corrosion behavior of X80 steel under the disbonded coatings through electrochemical methods when the AC stray current interference voltage was 0V, 1V, 5V or 10V and the protection potential was 0V, −0.9V, −1.0V, −1.2V or −1.3V, respectively. There is great significance to the safe operation and long-term service of pipeline steel in soil environment.

Details

Anti-Corrosion Methods and Materials, vol. 66 no. 6
Type: Research Article
ISSN: 0003-5599

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Article
Publication date: 12 December 2018

Zili Li, Chao Yang, Gan Cui, Shouxin Zhang and Chengbin Zhang

When hydrogen evolution reaction occurs on a metal surface, on the one hand, the generated hydrogen atom may penetrate into the metal that causes the hydrogen…

Abstract

Purpose

When hydrogen evolution reaction occurs on a metal surface, on the one hand, the generated hydrogen atom may penetrate into the metal that causes the hydrogen embrittlement failure of materials; on the other hand, the hydrogen generation may increase the local pressure in the coating and cause coating blistering. The purpose of this study is to study the effect of NaCl concentration and pH on hydrogen evolution reaction of X60 steel.

Design/methodology/approach

A cathodic polarization curve 257E-2V vs OCP and EIS was obtained by conventional three-electrode system in different NaCl concentrations, 257E3.5 and pH. Second, various parameters such as hydrogen evolution, over-potential current–density polarization resistance and capacitance of double electric layer were obtained based on fitting of the experimental data. Finally, the reaction mechanism was determined by Tafel curves.

Findings

It was concluded that in different NaCl concentrations, diffusion layer induced by concentration polarization affects the diffusion process of H+ ions, which makes over-potential increase. Under great effect of concentration polarization, the reaction is different in acid and alkaline environments, and the dielectric layer shows the characteristic of meta-alkaline adsorption, which makes difference in mechanism.

Originality/value

This research not only has theoretical significance but also gains utilization prospect. Ultimately, this research could be applied to clear hydrogen evolution process and protect long-distance pipeline against delamination.

Details

Anti-Corrosion Methods and Materials, vol. 66 no. 2
Type: Research Article
ISSN: 0003-5599

Keywords

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Article
Publication date: 1 January 2016

Gan Cui, Zili Li, Chao Yang and Xiaoyong Ding

Under normal conditions, there are different protection objects inside and outside the gas station, so two sets of independent cathodic protection systems are adopted. At…

Abstract

Purpose

Under normal conditions, there are different protection objects inside and outside the gas station, so two sets of independent cathodic protection systems are adopted. At the same time, an insulating flange is applied at the position where trunk pipelines access to the gas station, which realizes electrical isolation of the structures inside and outside the station. However, as a result of short distance between the two cathodic protection systems, there will be stray current interference between them. The purpose of this paper was to study on the interference between cathodic protection systems of gas station and long distance trunk pipeline.

Design/methodology/approach

Based on the above, in this paper, first, the mathematical model of interference between cathodic protection systems was established and the control equations solved using the boundary element method. Second, the influence of cathodic protection system of gas station on long distance trunk pipeline and the influence of cathodic protection system of long distance trunk pipeline on gas station were studied separately using BEASY software. Finally, a new thought of cathodic protection design for local station was put forward.

Findings

It was concluded that there were serious interference problems between the cathodic protection systems of gas station and long distance trunk pipeline. By moving the potential control point to area outside the influence scope of anode ground bed could avoid the influence of cathodic protection system of gas station on long distance trunk pipeline. By moving the auxiliary anodes away from gas station could avoid the influence of cathodic protection system of long distance trunk pipeline on pipelines in gas station. The new thought of cathodic protection design could avoid the interference between the cathodic protection systems effectively.

Originality/value

It is considered that the results can guide cathodic design for gas station and long distance trunk pipeline. The results can also avoid the interference corrosion between the structures in gas station and trunk pipeline.

Details

Anti-Corrosion Methods and Materials, vol. 63 no. 5
Type: Research Article
ISSN: 0003-5599

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Article
Publication date: 21 October 2013

Clark Shi-Ming Tang, Thomas Li-Ping Tang and Xiao-Yan Li

This study aims to develop a Chinese core self-evaluations scale (CCSES) (Study 1) and examines the relationship between CCSES and self-reported job performance among…

Abstract

Purpose

This study aims to develop a Chinese core self-evaluations scale (CCSES) (Study 1) and examines the relationship between CCSES and self-reported job performance among entrepreneurs in private small and medium enterprises in People's Republic of China (Study 2).

Design/methodology/approach

In Study 1, the paper incorporated two indigenous Chinese constructs, team-based self-esteem and personal integrity, into the existing literature of CSE and developed a new CCSES using a sample of 300 Chinese entrepreneurs in Hangzhou, China. In Study 2, the paper validated the CCSES in a separate sample of 306 entrepreneurs and investigated the relationships between CCSES and self-reported job performance.

Findings

The paper identified four sub-constructs in the 13-item CCSES: personal self-esteem, team-based self-esteem, personal integrity, and self-competence. Results from exploratory and confirmatory factor analyses showed good psychometric properties and high reliability in Study 1. In Study 2, the paper found a good fit between the measurement model and the data, and a significant relationship between CCSES and the overall measure of job performance and its three components. Males had significantly higher Chinese core self-evaluations (CCSE) scores than females. There were no differences in CCSE scores across age and educational background.

Originality/value

Borrowing the CSE construct in the Western literature, the paper includes two indigenous Chinese constructs, team-based self-esteem and personal integrity, provides a new perspective of the CSE construct for entrepreneurs, and investigates its relationship with job performance in China.

Details

Journal of Chinese Human Resource Management, vol. 4 no. 2
Type: Research Article
ISSN: 2040-8005

Keywords

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Article
Publication date: 2 November 2015

Gan Cui, Zili Li, Lingyu Zhao and Xu Wei

The purpose of this investigation was to study these problems and design regional cathodic protection, using numerical simulation. Regional cathodic protection technology…

Abstract

Purpose

The purpose of this investigation was to study these problems and design regional cathodic protection, using numerical simulation. Regional cathodic protection technology is immature at home and abroad. This is reflected in the fact that in gas stations, there are many underground pipelines, which can lead to serious interference and shielding phenomena, and there are many grounding networks that can cause substantial loss of the cathodic protection current.

Design/methodology/approach

Based on the above, in this article, first of all, the mathematical model of the buried pipeline cathodic protection potential distribution was established and the control equations solved using the boundary element method. Second, the cathodic shielding effect in pipeline concentration areas, the effect of instrument equipment grounding systems on cathodic protection and the influence of DC stray current on the interference of pipeline corrosion were studied separately using BEASY software. Finally, the BEASY software was used for a regional cathodic protection design for a real gas station.

Findings

It was concluded that impressed current used in combination with sacrificial anodes for regional cathodic protection design is often the most economic and effective approach. However, the output current of the auxiliary anode is large with high energy consumption. In consequence, it may be recommended that the station pipelines should be laid on the ground, rather than under it.

Originality/value

It is considered that the results can guide regional cathodic protection design for real-life installations very well.

Details

Anti-Corrosion Methods and Materials, vol. 62 no. 6
Type: Research Article
ISSN: 0003-5599

Keywords

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Article
Publication date: 24 June 2020

Yang Zhao, Lin Wang and Yaming Zhang

The paper aims to clarify the importance of the psychological processing of contextual cues in the mining of individual attention resources. In recent years, the research…

Abstract

Purpose

The paper aims to clarify the importance of the psychological processing of contextual cues in the mining of individual attention resources. In recent years, the research of more open spatial perspective, such as spatial and scene perception, has gradually turned to the recognition of contextual cues, accumulating rich literature and becoming a hotspot of interdisciplinary research. Nevertheless, besides the fields of psychology and neuroscience, researchers in other fields lack systematic knowledge of contextual cues. The purpose of this study is to expand the research field of contextual cues.

Design/methodology/approach

We retrieved 494 papers on contextual cues from SCI/SSCI core database of the Web of Science in 1992–2019. Then, we used several bibliometric and sophisticated network analysis tools, such as HistCite, CiteSpace, VOSviewe and Pajek, to identify the time-and-space knowledge map, research hotspots, evolution process, emerging trends and primary path of contextual cues.

Findings

The paper found the core scholars, major journals, research institutions, and the popularity of citation to be closely related to the research of contextual cues. In addition, we constructed a co-word network of contextual cues, confirming the concept of behavior implementation intentions and filling in the research gap in the field of behavior science. Then, the quantitative analysis of the burst literature on contextual cues revealed that the research on it that focused more on multi-objective cues. Furthermore, an analysis of the main path helped researchers clearly understand and grasp in the development trend and evolution track of contextual cues.

Originality/value

Given academic research usually lags behind management practice, our systematic review of the literature to a certain extent make a bridge between theory and practice.

1 – 10 of 141