滨海电厂冷凝器应用管材的评价研究

发布时间：2018-02-14 02:00

本文关键词： 冷凝器力学性能耐蚀性能模糊数学　出处：《中国石油大学(华东)》2014年硕士论文　论文类型：学位论文

【摘要】：冷凝器作为辅助发电机组的重要冷却设备。它的好坏直接关系到整个发电厂的稳定运行。目前国内电厂选用铜管(海军铜管、含砷黄铜管)或钛管。对铜管而言,由于冷却水多为海水或咸水,Cl-的质量浓度较高,极易诱发铜管的点蚀和缝隙腐蚀导致凝汽器泄漏,引起入炉水质恶化等一系列安全问题;同时,由于铜材价格飞涨,更换凝汽器的全部铜管对投资总额和运行维修费用的影响较大。钛管的使用能极大的改善冷却管抗局部腐蚀能力,减缓由凝汽器泄漏引发的一系列问题。然而,钛管的造价过于昂贵,寻找一种能够降低成本且性能优良的材料势在必行。超级铁素体作为一种较新的应用材料,具有高强度、低热膨胀系数、耐腐蚀特点,符合滨海电厂的工作要求。本文选取S44660超级铁素体、TA2钛、B30铜三种常用管材作为研究对象,对三种管材进行多方面的评价,通过评价结果,选出最适合滨海电厂的冷凝器管材。本论文通过拉伸实验对三种材料的强度与拉伸率进行了简单分析,三者材料中,超级铁素体S44660强度与拉伸率明显好于钛TA2与铜B30。通过洛氏硬度法测试得出,三种材料的HRB硬度值相差不远,处于90-100HRB之间,都达到了滨海电厂冷凝器管材要求。从电化学极化曲线分析,在不同pH值、盐度、温度中,钛TA2与超级铁素体S44660腐蚀电流密度相差不远,在高盐度中,S44660超级铁素体表现出较强的抗氯蚀性,它是三种材料中最耐氯蚀的管材,最适合在海水为冷却水的滨海电厂工作。相比而言,B30铜的腐蚀电流密度明显大于其它两种材料,这说明三者中B30铜耐蚀性最差,在应用中最容易发生腐蚀。在前文实验基础上,本文结合评价方法,创新性地引用了模糊决策理论,通过安全、耐蚀、经济三大准则层,建立各因素判断矩阵,完成对不同指标的考察,通过计算矩阵,得出各因素权重值大小,从权重值大小判断得出S44660超级铁素体是最适合滨海电厂环境的冷凝器管材。
[Abstract]:Condenser is an important cooling equipment for auxiliary generator set. Its quality is directly related to the stable operation of the whole power plant. At present, copper tube (navy copper tube, arsenic containing brass tube) or titanium tube are used in domestic power plants. Because the cooling water is mostly seawater or salt water with high concentration of Cl-, it is easy to induce pitting corrosion and crevice corrosion of copper pipes and lead to a series of safety problems, such as leakage of condenser, deterioration of water quality in the furnace, etc. Meanwhile, the price of copper materials is soaring. Replacing all the copper tubes of the condenser has a great influence on the total investment and maintenance cost. The use of titanium tube can greatly improve the local corrosion resistance of the cooling tube and alleviate a series of problems caused by the condenser leakage. The cost of titanium tube is too high, it is imperative to find a kind of material which can reduce the cost and have good performance. As a new application material, super ferrite has the characteristics of high strength, low coefficient of thermal expansion and corrosion resistance. In accordance with the working requirements of Binhai Power Plant, three kinds of commonly used pipes, S44660 super ferrite, TA2 titanium and B30 copper, are selected as the research objects, and the three kinds of pipes are evaluated in many aspects, and the evaluation results are given. In this paper, the strength and tensile rate of three kinds of materials are analyzed by tensile test. The strength and tensile rate of super ferrite S44660 are obviously better than that of titanium TA2 and copper B30.The results of Rockwell hardness test show that the HRB hardness of the three kinds of materials is similar to that of 90-100 HRB. According to the electrochemical polarization curve, the corrosion current density of titanium TA2 and super ferrite S44660 is not different from that of super ferrite S44660 in different pH, salinity and temperature. The super ferrite S44660 shows strong resistance to chlorine corrosion in high salinity, and it is the most resistant to chlorine corrosion of the three kinds of materials. The corrosion current density of B30 copper is obviously higher than that of the other two kinds of materials, which shows that the corrosion resistance of B30 copper is the worst and the corrosion is the most likely to occur in application. In this paper, the fuzzy decision theory is innovatively cited in combination with the evaluation method. Through the three criteria of safety, corrosion resistance and economy, the judgment matrix of various factors is established, and the inspection of different indexes is completed, and the matrix is calculated. The weight value of each factor is obtained and judging from the weight value it is concluded that S44660 super ferrite is the most suitable condenser tube for coastal power plant environment.
【学位授予单位】：中国石油大学(华东)
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM621

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