【作者】 付强；

【导师】 余艳芝；

【作者基本信息】 武汉大学 ， 热能工程， 2005， 硕士

【摘要】 近年来,大型锅炉过热器和再热器超温爆管现象已经日益频繁,机组被迫停运检修的情况时有发生。而且,相当大一部分机组在不同程度上出现了整体或局部上的工质超温或欠温的现象。这些显然对机组安全、经济运行不利。高温过热器、再热器的管壁温度的准确计算与监控对于锅炉设计与运行中的具有极为重要的意义。但锅炉复杂的结构和经常性非设计工况下的工作,使准确计算受热面壁温变的困难,如何准确计算受热面壁温成为迫切要解决的问题。 本文介绍的电站锅炉过热器、再热器变工况三维壁温计算,是一种新的较为精细的校核受热面管壁温度的方法。该方法舍弃了以前那种通过取各种修正系数、对平均量进行修正的计算受热面壁温的思路,而是将过热器、再热器受热面管组离散化为若干小单元,然后对每个离散化的小单元逐一计算热平衡关系,得到受热面详细的三维壁温分布。该新方法更精确的反映了锅炉过热器、再热器壁温分布的内在本质,并使计算方向趋向简明。 本文以宁夏电厂330MW旋流对冲锅炉为例,对其分隔屏过热器、后屏过热器、高温过热器、高温再热器进行三维壁温计算。为了使计算更具有现实意义,本文分别计算了锅炉在燃烧设计煤种时,7种运行工况下锅炉过热器、再热器三维壁温分布。并根据计算结果对330MW锅炉过热器、再热器系统的设计和材料作出评价。更多还原

【Abstract】 In recent years, the failures of super-heater and re-heater occur frequently in the large-capacity boiler, which result in shutdown of the unit. To some extent, excessive temperature exist in super-heater and re-heater of many large units, which prevents the units from working safely and economically. The exact calculation and monitoring to the tube temperature of super-heater and re-heater are very important. Because the structure of boiler is very complex and it operates in the different conditions, the real temperature of super-heater and re-heater is very difficult to get. It is necessary to find a new way to solvethis problem.The three-dimensional calculation introduced in this paper is a new method. It cancalculate the super-heater and re-heater’s tube temperature when the boiler works under the varying operating conditions, and the calculation will be more particular and the result will be more various. This method is different from the old ones, which calculate the average tube temperature and consider the difference caused by the tube’s position. Firstly, the tubes are divided into many small segments, then the thermal equilibrium principle applied to each segment and the tube temperature calculated, lastly, the three-dimensional distribution of temperature of heat walls is calculated. This new method predicts the distribution of the super-heater and re-heater’s tube temperature more precisely, and the concept of the calculation is more concise.We calculate the anterior-screen super-heater, hider-screen super-heater, high temperature super-heater and high temperature re-heater of 330MW boiler in ZhongNing power plant. In order to enable the calculation to have the practical significance, we calculate separately the tube temperature when the boiler burn the design coal, and when the boiler work under 7 kind of operating conditions, and an appreciation on these is made.更多还原