Steam generator furnace pressure 4

[Scruel]

Hello to everyone, i work at a thermal power plant that a firing optimisation and rehabilitation project is going on now. We have started to commisioning at unit 1. But we have a problem. Problem is following, before the rehabilitation furnace presseure was fluctuating between -2 and 0 mbar but now it is fluctuating between -8 and 0 mbar. Do you think what must be the fluctutating range ? And how can i find a standard or other document about this subject.

 

[ash9144]

You are pulling too "deep" of a draft. If natural convection then check your dampers that they are set properly. If forced you may have a problem with a fan or other mechanism.

 

[Scruel]

Yes we have a forced convection. We think that problem is ID fans. But i wonder that what must be fluctuating rate of furnace pressure. Thanks for reply.

 

[athomas236]

For long term fluctuations I would look at ID fan controls, for short term fluctuations I would look at burner controls and set up.

athomas236

 

[ccfowler]

I agree with athomas236, but I would pay some attention to the forced draft fan controls as well.

Also, partial plugging of regenerative air heaters could be introducing instabilities that could be disturbing the responses of the fan control systems. If the frequency of pressure fluctuations is similar to the rotating frequency of the air heaters, then I would want to pay this possibility more serious attention.

 

[boilerone]

This is what I learned from the operators: to determine if it is the fan control making the problem, temporarily switch to manual and see if the pressure variation goes away.

If the fans are eliminated as suspects, the next things to look at are burner control and fuel feeding.