【作者】 侯勇；

【导师】 刘文毅； 宋景慧；

【作者基本信息】 华北电力大学(北京) ， 动力工程（专业学位）， 2016， 硕士

【摘要】 在实际运行过程中,由于受到设计、运行、煤种改变等因素的影响,电站锅炉的实际排烟温度将会比设计值高10-40℃,从而大幅度降低了锅炉效率。为了提高锅炉效率,有效回收烟气余热已刻不容缓。但由于煤炭中普遍都含有一定量的硫分,在烟气余热利用的过程中,烟气中的水蒸气和硫酸蒸汽进入低温受热面时,与温度较低的受热面金属接触,就可能发生凝结而对金属壁面造成腐蚀,将会影响设备的安全运行与使用寿命。要想突破腐蚀的限制充分利用锅炉余热,烟水换热器材料的耐腐蚀性能便成为影响电站锅炉烟气余热深度利用的重要因素之一。有鉴于此,本论文将开展低温硫酸露点腐蚀机理研究,并对国内外不同酸露点计算公式进行对比；开发一系列新型材料,通过腐蚀失重试验、电化学试验和模拟烟气腐蚀试验等手段对它们的耐腐蚀性能进行比较,结果表明非晶合金和氟塑料相比较于20G钢、ND钢和316不锈钢,在各个试验中均表现出优异的耐腐蚀性能,耐腐蚀性能排序为：氟塑料>非晶合金>316不锈钢>ND钢>20G钢；最后,对新型耐腐蚀材料进行挂片试验、喷涂试验和真实烟气腐蚀试验等现场试验,充分证明新型材料在现场环境下具有优异的抗积灰和耐腐蚀性能。本文的研究方法及成果将为电站锅炉低温烟气环境下的耐腐蚀材料优选提供重要的理论依据,有助于推动电站锅炉尾部余热利用系统由理论分析走向工程实践。更多还原

【Abstract】 In the actual operation process, because of the design, operation, coal and other reasons, the actual exhaust gas temperature will be 10-40℃ higher than the design value in many coal-fired power plants, reducing the efficiency of the boiler. It is no delay to effectively recovery flue gas waste heat so as to improve boiler efficiency. There is a certain amount of sulfur in the coal. In the process of flue gas waste heat utilization, when the steam and sulfuric acid vapor in the flue gas flows through low temperature heating surface, they will condense in the metal wall with a low temperature. The corrosion will affect the safe operation and service life of the equipment. In order to absorb the boiler exhaust gas waste heat, it is necessary to break the limitations of the corrosion. The corrosion resistance of material in water heat exchanger has become one of the important factors which affect the deep utilization of waste heat in power station.In summary, research will be carried out on the mechanism of low temperature sulfuric acid dew point corrosion, and all kinds of domestic and foreign acid dew point calculation formulas were compared; then a series of new materials will be prepared, the corrosion behaviors of materials were evaluated by corrosion weight-loss method, electrochemical tests and simulated flue gas corrosion tests. The results show that amorphous alloy and fluorine plastic showed excellent corrosion resistance in every test compared with 20G steel, ND steel and 316 stainless steel, and the corrosion resistance of these materials as follows:fluorine plastic> amorphous alloy> 316 stainless steel> ND steel> 20G steel; finally, the new materials were tested by coupon test, spraying experiment and real flue gas corrosion test, to prove that the new materials have excellent anti fouling and corrosion resistance in power plants.In this paper, the methods and results concluded can be important theoretical basis for the optimization of corrosion-resistant materials in low-temperature boiler flue gas, and will popularizes the waste heat utilization system to a large extent.更多还原