【作者】 王伟；

【导师】 刘宗德；

【作者基本信息】 华北电力大学(北京) ， 动力工程及工程热物理， 2021， 硕士

【摘要】 由于垃圾污染问题日益严重,垃圾处理压力随之不断增加,而垃圾焚烧发电作为处理垃圾的主要方式面临着严重的腐蚀问题。由于垃圾成分的复杂多变以及垃圾中含有大量的氯,所以垃圾燃烧产生过多的氯气与二氧化硫气体以及含有大量碱金属盐的飞灰。这些使得垃圾锅炉受热面的高温腐蚀要比燃煤锅炉严重得多。所以需要研究垃圾锅炉的高温腐蚀特性,并据此发展防护措施。垃圾发电锅炉的腐蚀因素包括氯腐蚀、硫腐蚀以及碱金属熔融盐腐蚀等,其中碱金属熔融盐腐蚀为最大的腐蚀因素。实验课题以C22、NiCrMo15和inconel 625合金粉作为实验材料,利用激光熔覆技术将三种合金粉熔覆制备并切割备用。使用KCl、NaCl、K2S04和Na2SO4以1:1:1:1的质量比例作为高温腐蚀试剂。使用管式炉模拟垃圾锅炉受热面的腐蚀温度,温度设定为500℃、550℃、600℃和650℃,腐蚀时长为24h、48h、72h直至288h,探究三种Ni-Cr-Mo合金熔覆层的耐腐蚀性能。使用扫描电子显微镜(SEM)、能量色散谱(EDS)和X射线衍射仪(XRD)对腐蚀产物进行表征。通过对腐蚀深度及速率的分析以及腐蚀产物的表征,可以得出以下结论:在试验温度下,耐腐蚀性能从强到弱的顺序为:inconel 625合金、NiCrMo15、C22;650℃下,inconel 625合金产生严重点蚀,C22合金和NiCrMo15合金主要为均匀腐蚀;C22和NiCrMo15两种合金材料受温度影响大,相比较下inconel 625合金在不同温度下腐蚀情况相对差异较小。三种材料在650℃下的腐蚀速率要明显快于600℃;500℃-650℃四个温度点的腐蚀产物均检测到Cr2O3,在600℃和650℃下的腐蚀产物还检测到NiCr2O4,以及观察到银白色金属液滴流出。更多还原

【Abstract】 As the problem of garbage pollution is becoming more and more serious,the pressure of garbage disposal continues to increase,and garbage incineration power generation as the main method of garbage disposal is facing serious corrosion problems.Due to the complexity of the composition of the garbage and the large amount of chlorine in the garbage,the combustion of garbage produces too much chlorine and sulfur dioxide gas and fly ash containing a large amount of alkali metal salts.These make the high temperature corrosion of the heating surface of the garbage boiler much more serious than that of the coal-fired boiler.Therefore,it is necessary to study the high-temperature corrosion characteristics of garbage boilers and develop protective measures accordingly.The corrosion factors of waste-to-energy boilers include chlorine corrosion,sulfur corrosion,and alkali metal molten salt corrosion,among which alkali metal molten salt corrosion is the biggest corrosion factor.The experimental subject uses C22,NiCrMo15 and inconel 625 alloy powders as experimental materials,and uses laser cladding technology to prepare and cut the three alloy powders for use.Use KCl,NaCl,K2SO4 and Na2SO4 in a ratio of 1:1:1:1 as high temperature corrosion reagents.Use the tube furnace to simulate the corrosion temperature of the heating surface of the garbage boiler.The temperature is set to 500℃,550℃,600℃ and 650℃,and the corrosion time is 24h,48h,72h and 288h.Explore the melting of three Ni-Cr-Mo alloys.Corrosion resistance of the coating.The corrosion products were characterized by scanning electron microscope(SEM),energy dispersive spectroscopy(EDS)and X-ray diffractometer(XRD).Through the analysis of corrosion depth and rate and the characterization of corrosion products,the following conclusions can be drawn:At the test temperature,the order of corrosion resistance from strong to weak is:inconel 625 alloy,NiCrMo15,C22;at 650℃,inconel 625 alloy produces Severe pitting corrosion.C22 alloy and NiCrMo15 alloy are mainly uniform corrosion;C22 and NiCrMo15 alloy materials are greatly affected by temperature.In comparison,the corrosion conditions of inconel 625 alloy at different temperatures are relatively small.The corrosion rate of the three materials at 650℃ is significantly faster than 600℃;Cr2O3 is detected in the corrosion products at the four temperature points of 500℃-650℃,and NiCr2O4 is also detected in the corrosion products at 600℃ and 650℃,and The outflow of silver-white metal droplets was observed.更多还原