分馏塔顶空冷换热器腐蚀环境的研究

发布时间：2018-06-06 03:14

本文选题：催化裂化 + 空冷器管束　；参考：《西安石油大学》2017年硕士论文

【摘要】：本文针对催化裂化装置分馏塔顶空冷器管束内侧的腐蚀行为进行了分析研究。对设备材料点蚀穿孔的原因进行分析,得到炼油厂催化裂化分馏塔顶空冷器管束腐蚀影响主要因素有氯离子、硫离子、温度和pH值等。选择了现场常用的三种管束材料(10#钢、20#钢、304钢),在模拟实际工况的介质的溶液中研究了各个因素对材料腐蚀行为的影响,为系统的腐蚀防护提供参考。对主影响因素Cl~-浓度、S~(2-)浓度、温度、pH值逐个进行试验,得到极化曲线和交流阻抗谱。极化曲线进行分析,拟合得到曲线的腐蚀电位Ecoor和年腐蚀率,分析得到致钝电流密度Ip、点蚀电位Eb等参数。对结果进行分析,判断各因素影响腐蚀行为的规律和显著性程度。通过交流阻抗谱,建立等效电路的方式对各个因素进行分析,确定各因素对腐蚀行为影响的规律和显著性程度。极化曲线和阻抗谱均表明,10#钢、20#钢和304钢的腐蚀性,随氯离子和硫离子的增大而增大;经分析比较发现,在所研究的温度和PH值变化范围内304钢的耐腐蚀性最强,而10#钢耐腐蚀性次之,20#钢强的耐腐性最差;对三种材料来说,温度的增加促进材料的腐蚀,PH值的增加抑制材料腐蚀。
[Abstract]:The corrosion behavior of the inner side of the tube bundle of the top air cooler in the fractionator of FCC unit was studied in this paper. By analyzing the causes of pitting perforation of equipment materials, it is found that the main factors affecting the corrosion of the top air cooler tube bundle of FCC fractionator in refinery are chloride ion, sulfur ion, temperature and pH value, etc. Three kinds of pipe bundle materials, such as Gui10# steel and 20# steel, are selected. The influence of various factors on the corrosion behavior of the material is studied in the medium solution simulating the actual working conditions, which provides a reference for the corrosion protection of the system. The main influencing factors such as Cl-concentration and temperature and pH value were tested one by one and the polarization curves and AC impedance spectra were obtained. The polarization curves were analyzed, the corrosion potential Ecoor and the annual corrosion rate were obtained by fitting the curves, and the insensitive current density I _ p and pitting potential E _ b were obtained. The results were analyzed to determine the law and significance of the influence of various factors on corrosion behavior. By means of AC impedance spectrum, an equivalent circuit is established to analyze each factor and determine the law and significance of the influence of each factor on corrosion behavior. The polarization curves and impedance spectra show that the corrosivity of the two steels increases with the increase of chloride ion and sulfur ion, and the corrosion resistance of 304 steel is the strongest in the range of temperature and PH value studied, and the corrosion resistance of steel 304 increases with the increase of chloride ion and sulfur ion, the results show that the corrosion resistance of steel 304 is the strongest in the range of temperature and PH value. The corrosion resistance of 10# steel was the second, and the corrosion resistance of steel 20 # was the worst. For the three kinds of materials, the increase of temperature promoted the corrosion of the material and the increase of PH value inhibited the corrosion of the material.
【学位授予单位】：西安石油大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TE986

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