火电厂湿法烟气脱硫系统烟囱的腐蚀与修复研究

发布时间：2018-05-25 15:43

本文选题：湿法脱硫 + 低温腐蚀　；参考：《青岛理工大学》2013年硕士论文

【摘要】：燃煤电厂排放的烟气中含有少量的SO2等腐蚀性气体，湿法脱硫（FGD）工艺在国内外火电行业的脱硫工艺中应用最为广泛，烟气经湿法脱硫后，无论是否加装气-气加热系统（GGH），脱硫后的烟气温度均低于烟气的酸露点，烟气中的腐蚀性气体与水蒸气结合形成酸性冷凝液，对钢筋混凝土烟囱低温腐蚀。腐蚀性冷凝液侵入混凝土引发钢筋锈蚀，混凝土结构的使用寿命大大缩短，并可能在短期内造成结构的腐蚀破坏。本文通过从威海某烟囱钢筋混凝土烟囱中不同高度的钻取芯样，对烟囱在腐蚀环境条件下各种腐蚀离子侵蚀路径进行研究，通过现场试验和实验室试验测定试件的腐蚀电位、CaCO_3含量、碳化深度、SO~(4-)离子含量、Cl~-离子含量、NO~(3-)离子含量、孔隙率、烟囱外壁的回弹值及其抗压强度，分析混凝土烟囱的腐蚀因素。试验结果表明：回弹法测定混凝土抗压强度和钻芯法检测混凝土强度均满足设计要求，混凝土的密实度高钢筋保护层厚度的满足设计要求，烟囱下部外侧的钢筋锈蚀概率低，基本无腐蚀活动；烟囱的外侧碳化轻微，积灰平台处和下部碳化十分严重；孔隙率表明混凝土的密实程度高；钢筋的保护层厚度均值较大；烟囱筒内上部混凝土离子侵入十分严重，，现有单筒式烟囱腐蚀破坏较为严重，其耐久性较差。本文对单筒烟囱的耐久性进行了综合分析和评价，结合当前我国的施工技术和经济性等方面因素，参考国外的相关技术及其实施的可行性，综合考虑烟囱腐蚀的研究，结合各个方面腐蚀因素，提出比较系统的修复措施，为现有烟囱的修复改造和今后烟囱的建造提供一定的参考。
[Abstract]:The flue gas emitted from coal-fired power plant contains a small amount of corrosive gases such as SO2. The wet desulphurization process is the most widely used in the domestic and foreign thermal power industry, and the flue gas is desulphurized by wet method. The flue gas temperature after desulphurization is lower than the acid dew point of the flue gas whether or not the gas-gas heating system is installed. The corrosive gas in the flue gas combines with water vapor to form an acid condensate which corrodes the reinforced concrete chimney at low temperature. The corrosion condensate invades the concrete and causes the corrosion of the steel bar, the service life of the concrete structure is shortened greatly, and may cause the corrosion damage of the structure in the short term. In this paper, the corrosion paths of various corrosion ions of a chimney under corrosive environment are studied by drilling core samples from different heights of a reinforced concrete chimney in Weihai. The corrosion potential (CaCO3) content and carbonation depth (so _ (4) ion content of the specimen were determined by field and laboratory tests. The corrosion factors of concrete chimney were analyzed. The corrosion factors of concrete chimney were analyzed by means of the corrosion factor of concrete chimney, including the ion content, porosity, the rebound value and compressive strength of the outer wall of the chimney, and the corrosion factors of the concrete chimney were analyzed. The test results show that the compressive strength of concrete measured by rebound method and the strength of concrete measured by drilling core method meet the design requirements, the thickness of concrete with high compactness meets the design requirements, and the corrosion probability of steel bar outside the lower side of chimney is low. The outside carbonation of chimney is slight, and the carbonation of the ash deposit platform and the lower part is very serious; the porosity indicates that the density of concrete is high; the thickness of protective layer of steel bar is larger; The concrete ions in the upper part of chimney tube are very serious, the corrosion damage of single chimney is serious, and its durability is poor. In this paper, the durability of single tube chimney is comprehensively analyzed and evaluated. Considering the factors of construction technology and economy in our country at present, and referring to the relevant technologies abroad and the feasibility of their implementation, the study on the corrosion of chimney is considered synthetically. Combined with various corrosion factors, this paper puts forward some systematic repair measures, which can provide some references for the repair and reconstruction of existing chimneys and the construction of chimneys in the future.
【学位授予单位】：青岛理工大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TU761.2

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