Abstract: For the sake of preventing the accidents of bursted tubes caused by both supercritical boiler oxide skin spalling and over-temperature, the paper was aimed at developing an operation control technology for supercritical boiler based on safe temperature change rate. A relationship was deduced between oxide skin exfoliation's critical temperature change rate and boiler's run time after studying the relationship between oxide skin thickness in tubes of supercritical boiler and run time. A certain 600 MW supercritical boiler in China was taken as an example, for which control lines of the safe temperature change rate preventing the oxide skin in supercritical boiler's tubes from exfoliating at different run time, different materials and different temperatures were drawn on the basis of data on the engineering safety margin. The results show that there is a negative correlation between the safety temperature change rate of the supercritical boiler and both the operating temperature and run time, that the safe operation control technology saying "starting the boiler uniformty", "shutting down the boiler acceleratively" and "shutting down the boiler and cleaning tubes", which is based on the smallest safe temperature change rate, should be adopted for different pipes.

Key words: supercritical boiler, oxide skin spalling, burst tube, safe temperature change rate, safe operation control technology