SHELL drum level while driving
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How to tell if the liquid level in the steam drum while driving is a false level.
70–80%. If the liquid level is too high, it becomes difficult to control the pressure, and water can be carried in; it is essential to purge the steam drum before starting up
It is precisely because we knew it was a false liquid level that we kept the initial liquid level above 70.
There is a fixed amount of fluid that needs to be added before driving. If, during driving, the liquid level rises while the amount of fluid added does not increase or only increases slightly, then it must be a false liquid level reading. There’s also the amount of water that needs to be added as experience gains; after driving normally, there is a certain amount of water that needs to be added – remember that amount and take it into consideration in your overall planning
We usually compare the on-site situation with that from the control room, and generally the on-site information takes precedence.
This post was last edited by Tianya Langji on 2009-9-6 at 15:01. The drainage volume can be increased, along with the water supply volume, in order to quickly remove the heat generated by the vaporization furnace; this prevents foam from forming in the steam drum and avoids the occurrence of false liquid levels. Once all the burners are in use, the drainage/water supply volume can be gradually reduced to normal levels. However, this will lead to waste of boiler feed water. Be careful: do not stop the water supply as soon as you see that the liquid level is high. During normal driving, the high liquid level interlock and steam temperature interlock are usually disabled, and they are reactivated once normal operation is resumed.
Based on the three-momentum control principle, as the liquid level rises, the steam production also increases; this is considered to be a false liquid level