Dry And Wet Mode in Supercritical Boiler

#wetmode #drymode #thermalpowerplant
Wet and Dry Mode operation of supercritical boiler
Wet Mode
Operation of the boiler in which we get a mixture of water and the steam at the exit of boiler(vertical tubes) .In this condition the steam separates from water in separators because the boiler tubes from bottom ring header of boiler to separator filled with water thats why we call it wet mode
In wet mode operation we use Boiler Recirculation Pump /BCP to pick water from the separator and put it back at the economiser inlet so a flow can be maintained in the boiler . This circulating water helps to avoid tube damage which occurs due to localised heating of eco tubes and boiler tubes.
Dry Mode
As the name suggests in dry mode there is no moisture or water present in the separator and the exit of the boiler .
This type of operation is taken into service when we reach a certain load where the main steam flow is more than 40% subsequently we have sufficient flow of feed water at the inlet of the economiser to prevent damage of tubes due to thermal stress (tube leakage) . Now we don't need any recirculating water so we have to stop the BCWP .
The Dry Mode also called as Once through Mode because there is no recirculation happens in boiler
For Dry mode operation the separator outlet temperature should be greater than saturation temperature and we have to maintain dT greater than 17 deg centigrade . So we can ensure the dryness of steam .

[@lingarajpradhan]

Sir Very nicely explained. I will share with my colleagues.

[@BhagwanSRathore]

Thanks

[@e-music3845]

I looked for every video

[@desseado1234]

Nicely explained Rathore sir.
One doubt sir . How to know which saturation temperature to check at separator outlet ? When we are slowly increasing the load of the boiler , pressure is increasing, so is the saturation temperature ? .

[@BhagwanSRathore]

You can get saturation temp from the steam table or from your operating system which gives you sat temp wrt pressure
If you increase the pressure the saturation temp will also increase accordingly till you get 221 bar at this point 373 deg c is the sat temp this is the maximum saturation temp of water or say critical point condition after this if you increase the pressure the saturation temp will always be 373deg c
Case 1
Sep temp is less than or equals to saturation temp than water will rise in the seperator you need to control it by lowering feed water
Case 2 if sep temp is very high compared to sat temp you need to give more water to maintain proper dT
So if the separator is going down it means you are maintaining higher dt
And giving less feed water
And if the separator goes high it means you are giving more feed water than required
Thats why we maintain greater than 17 deg c dT in dry mode so there should be no water present in the separator

[@MrSomenath1986]

Why this parameter archive eco inlet feedwater temperature and high pressure heater outlet difference more than 10deg during wet to dry mode change over

[@NarendraKumar-uk7wd]

This 660mw blr is made of BHEL OR SOME OTHER COMPANY?

[@BhagwanSRathore]

Bhel

[@motive0507]

Sir,Could you please tell me about BMCR and TMCR simply

[@motive0507]

Sir please explain this simply
BMCR is maximum MS flow right?
please tell me about TMCR

[@BhagwanSRathore]

Boiler maximum continuous rating or the highest capacity of boiler to continuous steam produce
Turbine maximum continuous rating is the maximum load capacity which is generally 10% higher than rated like for 660 mw unit it will be 660+10%

[@gopikrishna.m8460]

sir, please explain feed water control loop, keeping in auto

[@BhagwanSRathore]

Please go through the playlist on the channel so you will find what u looking for

[@e-music3845]

Sir please make grade video in power plant

[@BhagwanSRathore]

You mean grid?

[@sudhirsingh3328]

Sir make a video on feedwater controller of super critical Boiler

[@BhagwanSRathore]

Thanks for the comment i will try to do so