COUNTERMEASURES FOR MAIN STEAM OVERTEMPERATURE OF 600 MW SUPERCRITICAL UNIT DURING TURBINE SPEED-UP

A 600 MW unit supercritical unit encountered the problem of higher temperature and lower pressure of main steam on boiler side during turbine speed-up,which do not fit in with the required parameters during turbine speed-up.To address this problem,the following measures are proposed:keep the fuel consumption at 12-13t/h and stop low feedwater protection during speed-up.Reduce the feedwater flow rate to 160-180t/h.Put HP and LP heater at soon as the turbine starts to speed up,with the feedwater temperature up to 200 ℃.After the above measures have been implemented,main steam temperature is controlled at 400 ℃,main steam pressure 6-8.73Mpa and boiler water wall temperature below 350 ℃.In this way,not only main steam overtemperature problem is solved but also fuel is saved.It has both economy and safety benefits.