海水中阴极保护35钢有限元模拟研究

设计了海水中铝基牺牲阳极阴极保护35钢的电极电位分别处于保护范围内、过保护、欠保护状态下的物理模型,推导Laplace方程的弱形式,方便了有限元程序设计。利用Kriging网格化插值法比较了有限元计算和实验数据。结果表明,有限元法模拟计算三种保护状态下的电位分布接近测量值。     

土壤电阻率和阳极埋设方式对长输管线阴极保护电位分布的影响

为了研究土壤电阻率和阳极埋设方式对长输管线阴极保护电位分布的影响,建立了长输管线阴极保护的简单物理模型,利用边界元算法的管单元法建立相应的数学模型,采用Matlab编程进行模拟求解。首先设计试验验证模拟结果的正确性,然后分别设定了不等的电阻率以及不同的阳极埋设方式进行模拟计算。结果表明,不同的土壤电阻率和不同的阳极埋设方式均会对长输管线阴极保护电位的分布产生很大影响。     

钢质贮罐底板外侧阴极保护时的电位分布

钢质贮罐底板外侧阴极保护时的电位分布往往不均匀。本文用有限元法计算了几种情况下的电位分布和电流分布规律,并在此基础上讨论了多种因素对电位分布的影响,包括土壤的电阻率、贮罐底板外侧表面状态、阳极的数量和分布以及极化量等。这些结果可以解释罐底阴极保护的特征。这个计算方法可用于贮罐底板外侧阴极保护系统的设计。     

基于深井阳极阴极保护技术的储罐等级研究

针对以往深井阳极对储罐底板阴极保护数值模拟中存在的缺陷:金属构件极化曲线试验限定条件不同导致电位计算系统误差;没有考虑计算区域环境介质的不连续性,本文提出一种根据典型电流密度分布假设求解保护电位的方法:计算区域由土壤和沥青砂基础构成,根据阴极保护体系物理模型近似计算深井阳极极化电位。数值结果与现场实测电位数据对比验证了数值方法的可靠性,研究了单支深井阳极完全有效保护的临界储罐直径(等于56米)。     

长输管线阴极保护电位分布的数值模拟

建立了长输管线阴极保护电位分布的简单物理模型,并采用边界元算法的管单元法推导出电位分布的简单数学模型,以实测阴极极化曲线作为边界条件,分段线性法进行拟合处理;依据以上的数学模型以及边界条件,采用Matlab工具编程,计算出长输管线阴极保护的电位分布,与试验设计测试的管线电位相比误差较小。讨论了管单元数目的划分对计算结果的影响,管单元数目的合理选择对于数值计算效率的提高和误差的控制很有意义。     

管线腐蚀与防护势态的灰色评估研究

分析了影响输油管线防护状态的4项因子即管地电位 、阴极保护电位、土壤中碳钢腐蚀电流密度以及防腐层电阻的统计分布特征,发现它们分别 服从正态分布或对数正态分布;且新旧两条输油管线的管地电位与防腐层绝缘电阻的均值与 方差具有显著性差异,而土壤腐蚀电流密度与阴极保护电位则不构成显著差异.应用灰色决 策（灰靶）理论对管线综合势态和运行风险进行了分级和评估,为减少管道腐蚀事故和管道 的预防性维修提供依据.     

典型站场区域阴极保护系统对线路阴极保护系统干扰的检测及处理

为了消除区域阴极保护系统对线路阴极保护系统的干扰,使线路阴极保护系统能够正常恒位运行,采用阴极保护电位分布数值模拟及干扰模拟计算的三维几何模型对干扰进行了分析,并通过现场测试对模拟进行了验证.根据模拟及现场测试的结果对干扰采取了有效的治理,消除了区域阴极保护系统对线路阴极保护系统的干扰,将线路恒电位仪的输出参数恢复至干扰前的水平.     

储罐底板阴极保护电流密度分布规律研究

建立了深井阳极对储罐底板阴极保护体系的数学模型,使用两种典型的电流密度假设求解保护电位,研究了储罐底板水平轴线、垂直轴线和斜对角线的电位分布情况,将数值计算结果与实测电位数据进行了对比,根据对比结果评价了两种电流密度假设的优劣性,这对于研究储罐底板电流密度分布规律和新建阴极保护工程具有一定的指导意义。     

外部结构对储罐底板外壁阴极保护电位分布影响的数值模拟计算

利用有限元和有限差分法,建立了储罐底板外壁阴极保护电位分布的数学模型,利用BEASY软件模拟计算外部结构对罐底外壁的阴极保护电位分布影响,包括接地类型、砂土层、阳极形式等。探讨了采用深井阳极对储罐底板外壁进行阴极保护时,输出电流较大、保护效果不理想的主要原因。     

用带状牺牲阳极对埋地钢管实施阴极保护时的电位和电流分布

用带状牺牲阳极对埋地长输钢管实施阴极保护时,沿着轴线方向的电位分布一定是均匀的。本文通过有限元法计算,进一步研究沿着管道圆周上的电位和电流分布的规律。结果表明,在研究的参数范围以内,沿着管道圆周的电位分布也是相当均匀的。土壤电阻率越低,电位极化值越大,但所需的保护电流也增大。防护性能好的涂层总是有利于阴极保护。阳极距离和管道外径对电位和电流分布没有什么影响。这些结果可以供工程上参考,同时说明用带状牺牲阳极对埋地长输钢管实施阴极保护是十分理想的。     

Cathodic protection of steel in concrete using magnesium alloy anode

Corrosion of steel embedded in concrete structures and bridges is prevented using cathodic protection. Majority of the structures protected employ impressed current system. Use of sacrificial system for the protection of steel in concrete is not as widely employed. The use of magnesium anodes for the above purpose is very limited. This study has been carried out with a view to analyse the use of magnesium alloy anode for the cathodic protection of steel embedded in concrete.Magnesium alloy anode, designed for three years life, was installed at the center of reinforced concrete slab, containing 3.5% sodium chloride with respect to weight of cement, for cathodic protection. Potential of the embedded steel and the current flowing between the anode and the steel were monitored, plotted and analyzed. Chloride concentration of concrete at different locations, for different timings, were also determined and analyzed.The magnesium anode was found to shift the potential of the steel to more negative potentials initially, at all distances and later towards less negative potentials. The chloride concentration was found to decrease at all the locations with increase in time. The mechanism of cathodic protection with the sacrificial anode could be correlated to the removal of corrosive ions such as chloride from the vicinity of steel.     

格形板桩码头牺牲阳极阴极保护效果检测与评估

对华南某港口5万吨级码头格形板桩牺牲阳极阴极保护效果的检测,详细介绍了检测的内容和方法.本工作采用修正的计算公式,准确计算了阳极的剩余寿命,分析了码头端部钢桩保护电位偏低的原因,并提出了一些维修建议.     

Throwing power of cathodic prevention applied by means of sacrificial anodes to partially submerged marine reinforced concrete piles: Results of numerical simulations

The paper deals with the determination of current and potential distribution in reinforced concrete elements partially submerged in seawater aimed at predicting the throwing power of cathodic prevention applied by means of sacrificial anodes. Experimental results from previous laboratory tests showed that the throwing power of cathodic prevention is higher compared to that of cathodic protection [1]. In order to extend the results obtained on small-scale specimens to elements of higher dimensions, FEM numerical simulations of potential distribution were carried out. Several cases were considered, representative of conditions differing in electrochemical behaviour of steel bars, geometry of the pile and of sacrificial anodes, concrete resistivity. The results allowed to discuss the role of different factors on the throwing power that can be reached by using sacrificial anodes immersed in the seawater to protect reinforcing steel bars in the emerged part of a pile.     

金塘大桥承台钢底板阴极保护

承台钢底板与钢管桩的绝缘较差时,钢底板将会吸收钢管桩的阴极保护电流,加速了牺牲阳极的消耗,最终牺牲阳极的寿命达不到设计年限,影响阴极保护效果.文章介绍了承台钢底板牺牲阳极阴极保护设计及施工.经检测,保护电位满足设计要求.     

淡水介质中筒状设备内壁阴极保护电位分布研究

研究了室温自来水介质中用镁合金牺我阳极保护Ａ３钢时,阴阳极之间的距离阴极保护时间及阳极数量对保护电位的影响。依据实验结果,对辽化某装置实施了阴极保护,取得了较好的效果。     

铁基牺牲阳极性能及其对12Cr钢管的阴极保护

采用恒电流试验测试了铁基材料在海水中的牺牲阳极性能,并结合12Cr钢管的极化和循环伏安曲线测试以及阴极保护的实海试验,分析了铁基阳极用于12Cr钢管牺牲阳极保护的可行性。结果表明,所选铁基阳极中材料C具有良好的牺牲阳极性能,工作电位稳定,电流效率高,溶解均匀,消耗慢;对12Cr钢管进行阴极保护时具有足够的驱动电压;实海阴极保护试验显示铁基阳极材料C对12Cr钢管有良好的保护效果。     

Possibility of High Phosphorus Pig Iron as Sacrificial Anode

Cathodic protection is an effective method to control the corrosion of underground pipelines and submerged structures. In the present work, high phosphorus containing pig iron was utilized as sacrificial anode for cathodic protection of underground mild steel plates and the results were compared with that of a commercially pure magnesium sacrificial anode. Driving potential and current between the galvanically coupled sacrificial anodes and mild steel plates were continuously monitored in real time for one month. Microstructure and morphology of the corrosion products formed on the surface of pig iron, magnesium sacrificial anodes and mild steel plates were observed with the help of optical microscope and scanning electron microscopy, and phase identification were performed using x-ray diffraction, Raman spectroscopy and Fourier transform infrared spectroscopy. The distribution of phosphorus in the pig iron matrix and soluble rust formation on the surface of pig iron under buried condition were critical from the point of sacrificial effect, indicating the possible scientific reasons for high phosphorous pig iron to be used as sacrificial anode.     

钢质石油储罐罐底外壁牺牲阳极阴极保护

本文对钢质石油储罐的腐蚀机理、因素进行了分析,介绍了牺牲阳极阴极保护的原理,对1座10000m3的钢质石油储罐罐底外壁进行了牺牲阳极阴极保护设计,并对其保护效果进行了检验。结果显示该储罐实施牺牲阳极保护后,牺牲阳极保持较低的工作电位,使罐底外壁得到相应保护,达到了设计技术要求,有效减缓罐底外壁的腐蚀速率。