Abstract: Flue gas dew point is the key indicator of low temperature corrosion, and restricts deep utilization of boiler flue gas heat. Fouling of heat exchanger surface is a major factor in deterioration of heat transfer. When fluid flows across heat exchange tubes, fouling and acid condensation influence heat transfer of heat exchanger. In the flue gas environment with dust and acid, a hot-state test was conducted to analyze heat transfer characteristics at different outer wall temperatures, and the dew point of flue gas for engineering application was obtained with a higher use value. The influence of the tubes' heat transfer characteristics with varying fouling and acid condensation was determined. Ash deposition with different amounts of acid condensation was investigated through analyzing the ash samples at different outer wall temperatures. The value of applied dew point for engineering was given as 72℃, which was at least 35℃ lower than the acid dew point in thermodynamics.

Key words: condensation, deposition, heat transfer, corrosion, acid dew point

摘要： 烟气露点是低温腐蚀的关键指标，制约着锅炉尾部排烟余热的深度利用。换热器表面积灰是传热特性恶化的主要原因，电站锅炉尾部烟气环境中，积灰与酸凝结共同作用影响换热器的传热特性。在含尘、含酸的烟气环境下对换热器传热特性进行热态实验研究，以套管换热器为基础，得到具有更高使用价值的烟气工程应用露点，结合传热特性随外壁温的变化情况，得到换热管传热特性随积灰及酸耦合的变化规律；并通过对不同外壁温下灰样的分析，得到不同酸凝结状况下积灰规律，得到实验环境下的工程应用酸露点温度为72℃，较传统热力学酸露点低35℃以上。

关键词: 凝结, 积灰, 传热, 腐蚀, 酸露点