How is the superheater protected during boiler startup?

I don’t know much about it; I only know in general that no steam is generated when the boiler starts up, so external steam is introduced into the superheater to cool its tubes and prevent damage.

In addition to the main boiler, power station boilers also have start-up boilers (usually chain-grate boilers or oil-gas boilers), which are used for warming the pipes and supplying steam to the main boiler’s superheater.

I know what was said upstairs, but thanks anyway

If it is a single furnace with no other steam supplied, how is the superheater protected during startup?

How is the superheater protected during boiler startup? When the boiler is operating normally, steam flows at high speed through the superheater tubes, and it is the cooling effect of this steam that ensures the safe operation of the tube metal. During startup, even though the flue gas temperature is not high, the tube walls may overheat. This is because, at the beginning of operation, there is no steam flowing through the superheater tubes or the amount of steam is very small; water accumulates inside the vertical superheater tubes. Until this water is removed, the superheater operates in a dry-burning condition. Additionally, the thermal deviation is also quite significant at this time. All of the above indicate that the cooling conditions for the superheater during boiler startup are poor, and some tubes may experience overheating. To prevent the superheater tube walls from overheating, when the flow rate is 10%–15% below the rated value, it is necessary to control the temperature of the flue gas entering the superheater, by means of limiting the combustion rate or adjusting the position of the flame center inside the furnace. As the pressure increases, the steam flow rate rises, and the cooling conditions in the superheater improve. At this point, it is possible to protect the superheater by limiting the steam temperature at its outlet; the steam temperature at the outlet of the boiler superheater should be 50–100°C lower than the rated temperature. The methods involve controlling the combustion rate and exhaust volume, as well as adjusting the position of the flame center inside the furnace or changing the excess air coefficient. However, from an economic perspective, it is not recommended to use changing the excess air coefficient as a method to regulate the steam temperature. This post was last edited by *aojoinson on 2009-2-15 15:19]

This thread contains information on the commissioning of coal powder boilers: http://bbs.hcbbs.com/viewthread.php?tid=229546&highlight=%C3%BA%B7%DB%B9%F8%C2%AF

I have worked on coal-fired boilers, those with four corners and cyclone types; feel free to discuss any issues