应用EFM和CMAS评价缓蚀剂对P110钢的缓蚀效果

针对P110钢在模拟油田采出水中发生的严重腐蚀情况,采用一种双季铵盐类复配缓蚀剂对其进行腐蚀防护.通过失重挂片法,电化学频率调制技术和耦合多电极技术评价该缓蚀剂的缓蚀性能.结果表明,该缓蚀剂能够有效地抑制P110钢的腐蚀,在60 ℃,当复配缓蚀剂的浓度为150 mg/L时,缓蚀率达到95.31%,在90 ℃时虽然缓蚀率不高,但是能够有效的抑制局部腐蚀.电化学频率调制技术 (EFM) 和耦合多电极矩阵传感器(CMAS) 均能够用于监测金属的腐蚀情况,评价缓蚀剂的缓蚀性能.通过EFM校验因子能够清楚地表明该缓蚀剂对局部腐蚀的抑制效果,而通过CMAS表明,缓蚀剂在金属表面上的吸附能够有效地消除金属表面上存在的阴极点和阳极点,从而抑制金属的局部腐蚀.

Evaluation of Corrosion Inhibitors for P110 Steel in Simulated Oilfield Produced Waters Using EFM and CMAS Techniques

Inhibition performance of a complex inhibitor of bis-quaternary ammonium and thiourea (with mass fraction 1∶1) for the serious corrosion of P110 steel in simulated oilfield produced waters was studied by means of techniques of mass loss, electrochemical frequency modulation (EFM) and coupled multielectrode array sensors (CMAS). Experimental results indicate that this inhibitor could inhibit P110 steel from CO₂ corrosion efficiently. The inhibition efficiency was up to 95.31% when the concentration of inhibitor was 150 mg/L at 60 ℃. The inhibition efficiency decreased at 90 ℃, however, the inhibitor could eliminate the pitting corrosion of P110 efficaciously. EFM and CMAS techniques could monitor the corrosion process of the steel and evaluate the effectiveness of the inhibitor. The deviation from theoretical value of causality factor of EFM could reveal the effectiveness of the addition of inhibitor, i.e. the inhibitor could protect P110 from pitting corrosion. The results of CMAS showed that the prevention of pitting corrosion could be attributed to the adsorbing of inhibitor on the steel surface to relieve the concentrated distribution of cathodic and anodic currents.