| 摘要 |
PURPOSE:To make it possible to completely clean a boiler without impairing the heat transfer surface thereof and to completely recover the heat exchange ability thereof by temporarily raising the surface temperature of a heat transfer part to a decomposition temperature or higher at which a solid product is decomposed thereby to decompose and remove the solid product, and thereafter restoring the heat transfer part to a normal condition. CONSTITUTION:At a time point where the lowered performance of a boiler is detected by means to measure the pressure difference of a waste gas or to measure the flow rate of a generated vapor, the temperature of the heat transfer pipe of a waste heat boiler 3 is raised. When the temperature of the heat transfer pipe is raised up to a decomposition temperature or higher at which a salt of ammonium sulfate is decomposed and a short time is passed, the salt of ammonium sulfate adhering to the heat transfer pipe and the like is decomposed and again formed into a sulfurous acid gas SO3, ammonia NH3, and a steam H2O and is discharged in the form of a waste gas 1c. Thus, at a time point where the salt of ammonium sulfate has been removed from the heat transfer pipe, an air flow pressure is reduced and the heat exchange ability is recovered, and hence the temperature of the heat transfer pipe is again reduced and the operation is shifted to a normal operation. The above described steps are repeated to continue the operation. |
