Why is the cross limit function in boiler and how does it work?

[smahsan]

Hi Dear's
I m not much aware about this function of boiler bcz i m not directly involve on board operation.Is it protection of boiler or just funtion of control the boiler operation?Here i make it clear that this is of large capacity of boiler 1000ton/h steam generation.Pressure 172 bar and temp 550degc
Thanks and regards
S.M.Ahsan

 

[GarethJones]

Cross limiting is carried out by the boiler control system and forms part of the boiler safety systems. Its function is to prevent a fuel rich condition by requiring the air flow to increase before fuel flow when the load is rising and fuel flow to decrease before air flow when the load is falling. It operates in conjunction with other parts of the control system such as the air/fuel ratio controls.

 

[unclesyd]

I strongly recommend that you get a copy of the book "STEAM" at his website. It offers a tremendous amount of information that you will need around boilers.

http://www.babcock.com/pgg/tt/steambook.html

 

[curve3104]

I would suggest finding the oldest version of "Steam". B&W got smart in thier later publishings and deleted a lot of good info.

 

[smahsan]

Thanks for the information shared by gareth jones and books recommendations.I will try to find this book.
Thanks and regards
Ahsan

 

[seo]

Another good source is "Control of Boilers" by Sam Dukelow.