Hydrodynamic and temperature effects on the flow-induced local corrosion rate in pipelines

When a flow enters a pipeline or goes over an obstacle, a new boundary layer is developed and produces a local corrosion rate that is greater than the average corrosion rate. Equations are developed to calculate this local flow-induced corrosion rate. The calculated local corrosion rate varies from a fraction of mm/year to 1.27 mm/year (50 mils/year), depending on the temperature, velocity, and location of the flow. The calculations also show that the maximum local corrosion rate occurs at a short distance from the edge of the pipe entrance. The wavy appearance of erosion-corrosion failure on metal surfaces can be explained by the boundary layer theory and the convective mass transfer of ferrous ions.     

HYDRODYNAMIC AND TEMPERATURE EFFECTS ON THE FLOW-INDUCED LOCAL CORROSION RATE IN PIPELINES

When a flow enters a pipeline or goes over an obstacle, a new boundary layer is developed and produces a local corrosion rate that is greater than the average corrosion rate. Equations are developed to calculate this local flow-induced corrosion rate. The calculated local corrosion rate varies from a fraction of mm/year to 1.27 mm/year (50 mils/year), depending on the temperature, velocity, and location of the flow. The calculations also show that the maximum local corrosion rate occurs at a short distance from the edge of the pipe entrance. The wavy appearance of erosion-corrosion failure on metal surfaces can be explained by the boundary layer theory and the convective mass transfer of ferrous ions.     

碳钢在固/液两相流条件下流动腐蚀的数值模拟

在单相流数值计算的基础上,引入固相颗粒运动理论,对双相流中的碳钢磨损腐蚀进行了数值模拟.结果表明：在0～18m•s^-1流速范围内,固体颗粒与材料壁面的碰撞角度、碰撞频度和碰撞速度等颗粒相力学参数对表面切应力、传质系数影响强烈,导致碳钢磨损腐蚀加剧,但对碳钢的切削磨耗作用不大.腐蚀速度的模拟计算值与实测值基本一致,验证了碳钢在两相流加剧腐蚀的协同效应中腐蚀电化学作用仍占主导地位.随着流速进一步增大,磨耗量虽小,但会有所增加.     

Mannich碱型缓蚀剂的合成

以苯乙酮、甲醛、乙二胺为主要原料,合成了一种适用于盐酸介质的Mannich碱型高效酸化缓蚀剂JKY,并将其与OP-10、甲醛复配,得到复配缓蚀剂．分析比较了各缓蚀荆的缓蚀效果。结果表明,60℃、常压下。在土酸（12％HCl＋3％HF）中加入质量分数为0．3％的缓蚀剂JKY,N80钢片腐蚀速率为1．431g·m^-2·h^-1。缓蚀率为98．3％;复配缓蚀剂有效地解决了单一Mannich碱型缓蚀剂水溶性差的问题,且抗HCl和HF腐蚀性能更好,其加量为1．0％时。在最佳复配比（JKY：OP-10：甲醛=0．7％：0．1％：0．2％）下,N80钢片腐蚀速率仅为0．294g·m^-2·h^-1,缓蚀率达99．65％。     

集输管道T型管内冲刷腐蚀数值模拟

T型管在油气集输系统中应用广泛,但容易形成冲刷腐蚀,发生泄漏事故,有必要对腐蚀影响因素进行研究。建立了流动控制方程,借助CFD软件对油气混输流体流经T型管进行流场和应力分析,探讨了流体组成、流体性质和流动参数等对冲刷腐蚀的影响。结果表明:T型管内壁面剪切应力的大小和分布受多种因素影响;最大壁面剪切应力分布在正对来流方向主管和支管的交接处。适当降低流速和流体粘度、增大含气率和支管直径可减缓T型管冲刷腐蚀。研究结论可为管道腐蚀防护和安全稳定运行提供理论依据。     

多苯环双子季铵盐在油水两相中的传质性能

采用紫外分光光度法测定了2种联结基不同的阳离子双子季铵盐缓蚀剂(bi-PDTBP和PDTBP)在油水两相中的分配系数，通过分配系数及有关理论，计算出2种阳离子双子季铵盐缓蚀剂在分配时的热力学参数，并系统考察了温度、油水比例、盐浓度、缓蚀剂浓度和时间对缓蚀剂在油水介质中迁移的影响；最后通过失重法研究了2种缓蚀剂在1 mol/L盐酸中对Q235钢的缓蚀性能。结果表明：温度和缓蚀剂浓度可促进缓蚀剂在油水介质中的分配，而盐浓度和油水比例会阻碍缓蚀剂在油水介质中的分配；另外，随着2种缓蚀剂浓度的增加，缓蚀效率逐渐提高，且bi-PDTBP在高温下的缓蚀性能优于PDTBP。     

一种新型抗高温酸化缓蚀剂的制备与性能评价

硫脲、多乙烯多胺、油酸按照质量比0.2∶1∶2,通过缩合脱水反应合成出了一种油酸硫脲基咪唑啉,并复配表面活性剂、吡啶、醛、炔醇等,得到一种新型抗高温酸化缓蚀剂LX-1,对缓蚀剂的缓蚀性能、相容性、抗温性能进行评价。结果表明,缓蚀剂的缓蚀性能良好,LX-1加量为0.6%时,缓蚀率达到95%,腐蚀速率达0.015 mm/a;与地层离子及各种化学剂相容性好;能抗高温90℃,盐酸浓度20%时,腐蚀速率0.023 mm/a,缓蚀率89.0%。     

双咪唑啉缓蚀剂抑制油田CO_2腐蚀的性能研究

以葵二酸、三乙烯四胺和氯化苄为原料,合成了双咪唑啉缓蚀剂。通过电化学阻抗法,研究了双咪唑啉缓蚀剂在饱和CO_2油田采出水介质中对J55油管钢的缓蚀性能,并对两口CO_2腐蚀严重的油井进行了现场加注试验。结果表明,双咪唑啉缓蚀剂在油田水介质中抑制CO_2腐蚀性能优异:加入缓蚀剂后可使电荷传递电阻大幅增加,在缓蚀剂浓度为150ml/L时,缓蚀率可达96.3%;两口试验井加注缓蚀剂后,腐蚀速率大幅下降,缓蚀率可达85%以上,现场使用效果优异。     

一种酸化缓蚀剂的合成及性能研究

以甲醛、乙二胺、苯乙酮为反应主要原料,利用Mannich反应合成了曼尼希碱缓蚀剂。最佳合成条件:反应温度50℃,反应时间12 h,pH值为4,苯乙酮、甲醛、乙二胺物质的量比为2:4:1。用静态失重法对其缓蚀性能进行了综合评价。结果表明,在90℃、15%的盐酸中加入1%的缓蚀剂,N-80钢片的腐蚀速率可以达到2.473 g/(m2.h),具有良好的缓蚀性能。     

双相不锈钢管固液两相流动腐蚀的数值模拟

在碳钢流动腐蚀数值模拟的基础上,针对管道流动体系,对固液两相流条件下双相不锈钢的流动腐蚀进行了数值模拟.模拟了固液两相流体动力学过程和双相不锈钢腐蚀动力学过程,模拟计算得到的腐蚀速率与实测值基本一致,表明建立的两相不锈钢流动腐蚀的综合数学模型是正确的,揭示了两相流中双相不锈钢的流动腐蚀机理,并进行了实验验证.两相流中双相不锈钢流动腐蚀的加剧主要是由于颗粒相的存在会大大强化液相流体的流体力学因素,导致钝化膜内传质速度加快所致.计算结果同时也表明,对于表面覆盖有钝化膜的材料的数值模拟,建立合理的流动腐蚀动力学模型是数值计算方法应用成功与否的关键.     

Amikacin disulfate: an aminoglycoside antibiotic drug as a corrosion inhibitor for copper in 1 M nitric acid medium

The effect of commercially available pharmaceutically active compound amikacin disulfate (AMK) against the corrosion of copper in 1 M HNO₃ solution was investigated using Tafel polarization, electrochemical impedance spectroscopy (EIS), and weight loss techniques. The results show that inhibition efficiency (IE %) increases with increasing inhibitor concentration from 0.1 to 1.0 mM. Increasing the temperature increased the corrosion rate, and results decreased the inhibition efficiency. The adsorption of inhibitor obeyed Langmuir adsorption isotherm model via physisorption mechanism. EIS technique exhibits one capacitive loop, indicating that the corrosion reaction is controlled by charge transfer process. Polarization measurements showed that the AMK is mixed-type inhibitor. The surface morphologies were studied by scanning electron microscopy and atomic force microscopic techniques. The corrosion mechanism were explained by Fourier transform infrared spectroscopy.     

基于热质传递解耦特性的溶液除湿过程传热传质系数(Ⅱ)实验与Le-hD分离测量法应用

对采用规整波纹填料结构的溶液除湿器除湿过程进行了实验研究,空气与溶液流型组织形式为叉流,基于Le-hD分离测量法得到空气入口流量、温度、含湿量以及溶液入口质量分数、温度对耦合传质系数的影响,并采用数据回归的方法对传质系数与Lewis数进行拟合,得到该类结构除湿器除湿过程的传质系数与Lewis数的关联式,并进行了74组稳态实验对该关联式进行误差分析与验证,结果表明根据关联式计算得到的进出口参数变化与实验进出口参数变化之间相对误差很小,进出口空气温度变化、含湿量变化误差分别仅在6%、10%以内,进出口溶液温度变化相对误差不超过12%,表明Le-hD分离测量法的准确性和可接受性。     

基于热质传递解耦特性的溶液除湿过程传热传质系数(Ⅱ)实验与Le-hD分离测量法应用

对采用规整波纹填料结构的溶液除湿器除湿过程进行了实验研究,空气与溶液流型组织形式为叉流,基于Le-h_D分离测量法得到空气入口流量、温度、含湿量以及溶液入口质量分数、温度对耦合传质系数的影响,并采用数据回归的方法对传质系数与Lewis数进行拟合,得到该类结构除湿器除湿过程的传质系数与Lewis数的关联式,并进行了74组稳态实验对该关联式进行误差分析与验证,结果表明根据关联式计算得到的进出口参数变化与实验进出口参数变化之间相对误差很小,进出口空气温度变化、含湿量变化误差分别仅在6％、10％以内,进出口溶液温度变化相对误差不超过12％,表明Le-h_D分离测量法的准确性和可接受性。     

一种高效盐酸酸化缓蚀剂的性能评价

采用静态挂片失重法和电化学法考察了缓蚀剂的缓蚀性能,讨论了缓蚀剂加量、温度对腐蚀速率的影响。静态腐蚀评价可知:结果表明,温度为90℃时,在15%工业盐酸介质中N80钢片的腐蚀速率随着缓蚀剂加量的增大而减小、随着温度的升高而增大。当缓蚀剂的加量为1.0%时,仍可获得光亮钢片表面,该缓蚀剂对N80钢片的缓蚀率可达到98%。电化学极化曲线和交流阻抗图谱结果表明:该缓蚀剂对金属腐蚀的阴、阳极过程均有抑制作用,属于混合型缓蚀剂,缓蚀机理属于"负催化效应"。通过电镜扫描照片可知腐蚀容易发生在钢片有局部缺陷的地方,且缓蚀剂的加入可有效的在钢片表面形成保护膜,阻止了腐蚀介质与钢片的接触,抑制金属的腐蚀。     

The effect of electrolyte flow rate and temperature on corrosion and protection of Al–2.5 Mg alloy by (+)-catechin

The effects of flow rate and temperature on the corrosion behaviour of the Al–2.5 Mg alloy in a 3% NaCl solution and the inhibiting efficiency of (+)-catechin on the corrosion of the same alloy have been examined. Measurements were carried out in a flow-through cell, at different flow rates (v ₁ = 0.0029 m s⁻¹, v ₂ = 0.0059 m s⁻¹ and v ₃ = 0.0118 m s⁻¹) and temperatures (20, 30, 40 °C). Electrochemical parameters for the Al–2.5 Mg alloy were determined by polarisation techniques and electrochemical impedance spectroscopy (EIS). Increased flow rate and temperature cause a stronger corrosion attack on the alloy. The addition of (+)-catechin inhibited corrosion at all temperatures and flow rates. The inhibitor efficiency decreased with increase in flow rate and temperature.     

Effect of pulp fiber suspensions on the rate of mass transfer controlled corrosion in pipelines under turbulent flow conditions

The present study aimed to investigate the corrosion behavior of a pipeline carrying dilute pulp fiber suspensions (0.1–0.3% consistency). To examine the role played by pulp fibers on the rate of diffusion controlled corrosion of metals an accelerated test which involved the diffusion controlled dissolution of copper in acidified dichromate was used under turbulent flow conditions. Different concentrations of pulp fibers at different solution velocities were studied. The rate of mass transfer controlled corrosion of copper was found to increase by increasing solution velocity and decrease by increasing pulp consistency. The data in the presence and absence of the pulp slurry were correlated by dimensionless equations.     

管道两相流冲刷腐蚀的CFD研究进展

介绍了冲刷腐蚀对石化行业的危害,阐述了影响冲刷腐蚀的因素,即主要是流体力学因素、材料因素、固相颗粒等因素的耦合作用。对计算流体力学(CFD)方法在管道防腐中研究的进展情况进行总结,指出了研究的优点和缺点。CFD数值模拟为防腐蚀研究提供了新的方法。通过模拟结果可以预测腐蚀的发生和发展,并为管道优化设计和工艺防腐提供可靠的理论依据。     

Eco friendly corrosion inhibitors: Inhibitive action of quinine for corrosion of low carbon steel in 1 m HCl

Quinine, a natural product, was investigated as a corrosion inhibitor for low carbon steel in 1.0 m HCl solution. Electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization were used to study the inhibition action in the temperature range 20–50 °C. The corrosion of steel was controlled by a charge transfer process at the prevailing conditions. The electrochemical results showed that quinine is an efficient inhibitor for low carbon steel and an efficiency up to 96% was obtained at 20 °C. The inhibition efficiency increases with inhibitor concentration and reaches a near constant value in the concentration range 0.48 mM and above. Application of the Langmuir adsorption isotherm enabled a study of the extent and the mode of adsorption.     

Mitigation of corrosion of zinc with amylopectin: Electrochemical,adsorption, and surface studies

Carbohydrate polymers are proven to be potential green corrosion inhibitors because of their outstanding structural features and eco-friendliness. Work undertaken reflects the effectiveness of biopolymer amylopectin (AMP) as an eco-friendly green inhibitor to mitigate the deterioration of zinc in 0.1 M sulphamic acid (NH₂SO₃H). Electrochemical studies like potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy (EIS) were applied for corrosion rate measurement in the absence and presence of AMP. Thermodynamic and kinetic parameters were calculated and described in detail. The results were fitted into a suitable adsorption isotherm model, and an appropriate mechanism was proposed for the corrosion inhibition process. A detailed surface morphology study was done using scanning electron microscopy (SEM), electron-dispersive X-ray (EDX), and atomic force microscopy (AFM) techniques. The inhibition efficacy of AMP increased with an increase in its concentration and temperature. Upon the addition of the inhibitor, corrosion potential shifted more towards the positive side, indicating more control of the anodic process. The adsorption of AMP over zinc conformed to the Freundlich adsorption isotherm. For the concentration of 0.1 gL⁻¹, maximum corrosion inhibition efficiency of 74% could be accomplished. Surface studies reaffirmed the adsorption of AMP on the surface of the metal. Thus, AMP turned out to be an effective green inhibitor with economic benefits.     

酰胺醚类酸洗缓蚀剂在1M盐酸中的缓蚀行为研究

以烟酰胺基甲基醚(NAME)为一种新型酰胺醚类缓蚀剂,采用失重实验、电化学阻抗、极化曲线和量子化学计算等技术,研究了在1M盐酸溶液中对Q235碳钢的缓蚀作用和机理。实验结果表明,随着NAME浓度的增加,缓蚀效率变大最高可达94.8%,吸附行为符合Langmuir吸附等温式;极化曲线结果表明,NAME是一种阴极抑制为主的混合型缓蚀剂;单容抗弧表明腐蚀过程为电荷转移步骤控制;量子化学计算结果表明,吸附活性中心是杂环、N、O原子上。