Under-deposit corrosion(UDC)due to the presence of deposits has become a major concern threatening the safe service of pipelines in oil and gas fields,causing economic loss and even irreversible damage to life and env...Under-deposit corrosion(UDC)due to the presence of deposits has become a major concern threatening the safe service of pipelines in oil and gas fields,causing economic loss and even irreversible damage to life and environment.Herein,we provide a critical review of UDC in terms of testing methods,corrosion mechanisms and mitigation strategies,so as to better understand and prevent UDC.Two deposit simulation methods and three UDC testing systems are summarized.Two popular UDC mechanisms are discussed based on the coverage and protectiveness of deposits,and the galvanic couple caused by the uneven distribution of deposits is found to be the root cause for the prevailed localized corrosion under deposits.The mitigation strategies for UDC are reviewed from the aspects of scale controlling and corrosion inhibition.In the last,the demands for developing accurate deposit simulation methods,effective UDC inhibitors and advanced on-site scale monitoring technologies are proposed.展开更多
The corrosion behavior of deposit-covered aluminum alloy 7075(AA7075)caused by fungus Aspergillus terreus(A.terreus)was thoroughly investigated in artificial seawater aiming to offer some new insights into the under-d...The corrosion behavior of deposit-covered aluminum alloy 7075(AA7075)caused by fungus Aspergillus terreus(A.terreus)was thoroughly investigated in artificial seawater aiming to offer some new insights into the under-deposit corrosion mechanism of aluminum alloys in marine environments containing fungi.Electrochemical impedance spectroscopy,polarization curves,wire beam electrodes,and surface analysis were performed.Results indicate that A.terreus can survive beneath the deposit but the counts of sessile spores decline as the increase of deposit thickness,suggesting a poor biological activity of A.terreus beneath the deposit.Both the uniform corrosion and pitting corrosion are accelerated by A.terreus,while the pitting corrosion of AA7075 alloys beneath the deposit derives from a galvanic cell with a small anode and a large cathode.Deposits have a corrosion inhibition effect on AA7075.However,the galvanic effect caused by the bare and deposit-covered AA specimens is obviously enhanced by A.terreus.展开更多
利用动电位扫描(PDS),电化学阻抗谱(EIS)和线性极化电阻法(LPR),研究了石英砂沉积物覆盖下的X65管线钢在含氧盐溶液中的腐蚀行为及有机膦缓蚀剂乙二胺四亚甲基膦酸钠(EDTMPS)的作用效果.通过丝束电极(WBE)对沉积物所导致的电偶效应进行...利用动电位扫描(PDS),电化学阻抗谱(EIS)和线性极化电阻法(LPR),研究了石英砂沉积物覆盖下的X65管线钢在含氧盐溶液中的腐蚀行为及有机膦缓蚀剂乙二胺四亚甲基膦酸钠(EDTMPS)的作用效果.通过丝束电极(WBE)对沉积物所导致的电偶效应进行了测试.结果表明,沉积物覆盖下的X65钢平均腐蚀速率变缓,但伴随有局部腐蚀发生.在溶液中加注35 mg/L的EDTMPS后,裸露的X65钢电极的腐蚀速率在3 h内由0.17 mm/a降低并稳定在0.082 mm/a,沉积物覆盖下的X65钢电极在6 h内腐蚀速率由0.051 mm/a降低到0.026 mm/a并保持稳定,EDTMPS对裸钢和沉积物覆盖下的碳钢均有良好的缓蚀效果.WBE电偶效应测试结果表明,沉积物覆盖区域电位较低,表现为阳极区并伴随有严重的局部腐蚀发生.在注入35 mg/L缓蚀剂后,WBE平均电位迅速下降,阳极区域逐渐减小,在加入EDTMPS缓蚀剂24 h后,最大阳极电流密度和阳极总电流分别从0.21 m A/cm2和0.056 m A降低至0.078 m A/cm2和0.021 m A.监测数据表明,EDTMPS对沉积物覆盖所引起的电偶效应也有一定的抑制作用.展开更多
基金financially supported by the Opening Project of Material Corrosion and Protection Key Laboratory of Sichuan Province(No.2017CL18)
文摘Under-deposit corrosion(UDC)due to the presence of deposits has become a major concern threatening the safe service of pipelines in oil and gas fields,causing economic loss and even irreversible damage to life and environment.Herein,we provide a critical review of UDC in terms of testing methods,corrosion mechanisms and mitigation strategies,so as to better understand and prevent UDC.Two deposit simulation methods and three UDC testing systems are summarized.Two popular UDC mechanisms are discussed based on the coverage and protectiveness of deposits,and the galvanic couple caused by the uneven distribution of deposits is found to be the root cause for the prevailed localized corrosion under deposits.The mitigation strategies for UDC are reviewed from the aspects of scale controlling and corrosion inhibition.In the last,the demands for developing accurate deposit simulation methods,effective UDC inhibitors and advanced on-site scale monitoring technologies are proposed.
基金supported by Guangdong Basic and Applied Basic Research Foundation,China(No.2023A1515012146)the National Natural Science Foundation of China(No.52271083).
文摘The corrosion behavior of deposit-covered aluminum alloy 7075(AA7075)caused by fungus Aspergillus terreus(A.terreus)was thoroughly investigated in artificial seawater aiming to offer some new insights into the under-deposit corrosion mechanism of aluminum alloys in marine environments containing fungi.Electrochemical impedance spectroscopy,polarization curves,wire beam electrodes,and surface analysis were performed.Results indicate that A.terreus can survive beneath the deposit but the counts of sessile spores decline as the increase of deposit thickness,suggesting a poor biological activity of A.terreus beneath the deposit.Both the uniform corrosion and pitting corrosion are accelerated by A.terreus,while the pitting corrosion of AA7075 alloys beneath the deposit derives from a galvanic cell with a small anode and a large cathode.Deposits have a corrosion inhibition effect on AA7075.However,the galvanic effect caused by the bare and deposit-covered AA specimens is obviously enhanced by A.terreus.
文摘利用动电位扫描(PDS),电化学阻抗谱(EIS)和线性极化电阻法(LPR),研究了石英砂沉积物覆盖下的X65管线钢在含氧盐溶液中的腐蚀行为及有机膦缓蚀剂乙二胺四亚甲基膦酸钠(EDTMPS)的作用效果.通过丝束电极(WBE)对沉积物所导致的电偶效应进行了测试.结果表明,沉积物覆盖下的X65钢平均腐蚀速率变缓,但伴随有局部腐蚀发生.在溶液中加注35 mg/L的EDTMPS后,裸露的X65钢电极的腐蚀速率在3 h内由0.17 mm/a降低并稳定在0.082 mm/a,沉积物覆盖下的X65钢电极在6 h内腐蚀速率由0.051 mm/a降低到0.026 mm/a并保持稳定,EDTMPS对裸钢和沉积物覆盖下的碳钢均有良好的缓蚀效果.WBE电偶效应测试结果表明,沉积物覆盖区域电位较低,表现为阳极区并伴随有严重的局部腐蚀发生.在注入35 mg/L缓蚀剂后,WBE平均电位迅速下降,阳极区域逐渐减小,在加入EDTMPS缓蚀剂24 h后,最大阳极电流密度和阳极总电流分别从0.21 m A/cm2和0.056 m A降低至0.078 m A/cm2和0.021 m A.监测数据表明,EDTMPS对沉积物覆盖所引起的电偶效应也有一定的抑制作用.
