真空相变锅炉低排烟温度设计与低温腐蚀

Discussion on the Conformable Super-low Exhaust Gas Temperature and the Low Temperature Corrosion Problem of the Phase Change Vacuum Boiler

真空相变锅炉是否会明显发生烟气低温腐蚀,一直众说不一。文章从锅炉发生低温腐蚀的机理入手,通过理论分析计算并通过实践检验,提出了真空相变锅炉虽然不能完全避免低温腐蚀问题,但不论排烟温度是否高于烟气露点,低温腐蚀的程度都很弱的观点;给出了真空相变锅炉沿烟气流程金属壁面的腐蚀速度与壁面温度的关系曲线,和烟气温度低于酸露点时金属壁面的腐蚀速度与壁面温度的关系曲线;同时,文章推荐真空相变锅炉的设计排烟温度取130℃左右的低排烟温度。根据上述观点设计的数百台产品已经过多年实际运行,未发现明显低温腐蚀。

It is uncertain all along that if the phase change vacuum boiler can be corroded obviously under super low temperature. In the present work, based on the mechanism of low - temperature corrosion, an opinion was presented by theoretical analysis and computation, that is the vacuum boiler can not avoid being corroded completely under low temperature, but the corrosion is very weak no matter if the exhaust gas temperature is higher than the flue gas dew point; it was obtained the relationship between the corrosion velocity of metal wall and wall temperature along gas pass of vacuum boiler, and the one between the corrosion velocity of metal wall and wall temperature under the condition that the flue gas temperature is lower than the acid dew point. The authorspecialized in the design of vacuum boilers for many years and has never found the obvious low temperature corrosion during the running of hundreds of products designed by the above opinion.