| 摘要 |
PURPOSE:To prevent heat transfer pipes from corrosion owing to high temperature, by changing the kind of coal or the mixing ratio of coal when the difference between the temperature of combustion gas in a high temperature part and the melting temperature of ash comes down below a predetermined value. CONSTITUTION:The temperature 3 in combustion gas at the outlet of a coal economizer, the temperature of combustion gas at the inlet of a reheater, the temperature in combustion gas at the inlet of a superheater, and the temperature in combustion gas at the outlet of a furnace (f) are calculated in turn from the temperature 3 in combustion gas at the outlet of a coal economizer and the absorption of heat of feed water passing through the pipes in a coal economizer, and also from the absorption of heat of steam passing through the pipes in a reheater and a superheater. The difference between the temperature in combustion gas and the melting temperature in ash is the allowable tolerance temperature 5 to fusion of ash. When the tolerance temperature 5 to fusion of ash in a high temperature part comes down below a predetermined value, the kind of coal or the mixing ratio of coal should be changed. By this method, heat transfer pipes disposed in the high temperature part of a furnace are prevented from being covered with melted ash, and are prevented from corrosion due to high temperature. |
