三分仓回转式空气预热器径向漏风对锅炉效率影响的研究及评估

Research and Evaluation on the Influence of Radial Air Leakage ofTri-sector Air Preheater on Boiler Efficiency

回转式空气预热器漏风问题是其不可避免的缺陷,其中径向漏风是最主要的漏风形式.以某电厂660MW机组锅炉的三分仓回转式空气预热器为研究对象,基于空气预热器整体建模的方式对其径向漏风特性进行研究,系统分析漏风率对转子易发生腐蚀积灰区域和锅炉效率的影响规律.结果表明:空气预热器的排烟温度随着热端径向漏风率的增加而升高,随着冷端径向漏风率的增加而降低,并且冷端径向漏风会加重低温腐蚀;热端径向漏风对排烟损失的影响远大于冷端径向漏风,排烟损失随径向漏风率的增加而增加;在锅炉最大连续蒸发量(BMCR)工况下,空气预热器热端径向漏风率每增加1%,锅炉效率降低0.02%.

The rotary air preheater has the inherent defect of air leakage, and the radial air leakage is the most influential air leakage form. Taking the tri-sector air preheater of a 600 MW unit boiler in a power plant as the research object, the characteristics of radial air leakage were researched based on the whole modeling of air preheater, while systematic analyses were conducted on the influence of the air leakage rate on the rotor area with a high risk of corrosion and ash accumulation, and the boiler efficiency. Results show that, the exhaust gas temperature of air preheater increases with the increase of radial air leakage rate at the hot end, and decreases with the increase of radial air leakage rate at the cold end;meanwhile, the radial air leakage at the cold end may aggravate the low temperature corrosion. Compared with the radial air leakage at the cold end, the radial air leakage at the hot end has a greater influence on the exhaust gas heat loss, and the exhaust gas heat loss increases with the increase of radial air leakage rate. When the radial air leakage rate at the hot end of the air preheater increases 1%, the boiler efficiency will decrease by 0.02% under boiler maximum continuous rating (BMCR) condition.