喷涂防结渣涂层锅炉过热汽温偏低问题及解决方案

Issues and solutions of low superheated steam temperature in boilers with anti-slag coating sprayed

中文关键词: 锅炉结渣  过热器欠温  陶瓷涂层  传热效果  数值模拟

英文关键词: boiler slagging  heater under-temperature  ceramic coating  heat transfer performance  numerical simulation

中文摘要:

      针对某台670 t/h燃煤锅炉喷涂防结渣复合陶瓷涂层后出现的过热蒸汽欠温问题，采用涂层材料传热参数测试和锅炉受热面传热数值模拟方法，分析上述问题产生原因并提出解决方案，结果表明：涂层发射率相较受热面金属材料显著提升，为0.9左右，而喷涂涂层后的热导率基本不变；将测得的发射率和热导率值用于锅炉传热模拟计算，发现喷涂涂层后锅炉水冷壁吸热量增加10.9%，大屏和后屏则分别减少7.2%和13.4%，受热面吸热比例失调是过热蒸汽欠温主要原因；通过模拟计算获得过热蒸汽欠温问题解决方案为，在原先喷涂方案基础上对大屏过热器全部进行喷涂，增加过热器吸热从而缓解过热器欠温问题，且该方案可有效降低NOx排放量。研究成果可供同类锅炉在防结渣涂层应用时的设计和改造提供参考。

英文摘要:

      The issue of overheating steam temperature deficiency observed after the application of a slag-resistant composite ceramic coating to a 670 t/h coal-fired boiler was analyzed through heat transfer parameter testing of the coating material and numerical simulations of the boiler's heating surfaces. The findings revealed that the emissivity of the coating significantly increased in comparison to the metal materials of the heating surfaces, reaching approximately 0.9, while the thermal conductivity of the sprayed coating remained nearly unchanged. Utilizing the measured values of emissivity and thermal conductivity for simulations of heat transfer in the boiler, it was discovered that the heat absorption of the water-cooled wall increased by 10.9% post-coating, whereas the heat absorption of the front and rear screens decreased by 7.2% and 13.4%, respectively. This imbalance in heat absorption across the heating surfaces was identified as the primary cause of the overheating steam temperature deficiency. Through simulation calculations, various solutions were assessed, with the optimal approach being the complete coating of the front superheater in addition to the original spraying plan. This adjustment will enhance the heat absorption of the superheater, thereby alleviating the problem of underheating while also effectively reducing NOx emissions. The research results can provide a reference for the design and modification of similar boilers in the application of anti-slag coatings.