ours is GE F 9E M/C is maintaining hi spreads, we have changed flow divider, clutch (warren pump), Warren pump, no water injection, nozzles were changed very recently, at 83MW spreads are suddenly raising to 55 to 61 + oc.pl give me an suggestion.

 

Changing liquid fuel pumps or clutches won't usually resolve a spread problem, since they are "common" to all combustors and exhaust T/Cs. When you changed these components, was it done one component at a time, or in a "shotgun" approach? If done one component at a time, what were the results? Did the location of the spread move or did it remain in the same location?

It's highly unlikely that yours is a controls problem.

The first suggestion would be: Provide more information about the spreads, their locations, etc. You haven't told us much about the spread problem.

When did this problem begin? After a maintenance outage? Suddenly? What changed, if anything, immediately before the problem started?

Is the spread always in the same area, or, when you change nozzles does the spread problem move? I've seen people change nozzles repeatedly, and the spreads move around the machine each time.

One of the biggest factors affecting spreads is the difference in flow characteristics of fuel nozzles. Each nozzle can be flow-checked to determine it's capability, and it's very common for many customers to put together sets of nozzles that are "matched" with each other very closely, to within say 5% of each other, or in some case, even less. Flow mismatches of more than 10% in a set of nozzles usually result in higher-than-normal spreads.

Liquid fuel nozzles can be a little more problematic than gas fuel nozzles because they are usually composed of multiple components. But, they can still be tested and matched for best results. Were components re-used when rebuilding the liquid fuel nozzles? How closely were the components checked for wear and tolerances? Do you buy your components from the OES or from an aftermarket source? What kind of confidence do you have that you receive components with similar tolerances?

Have any exhaust T/Cs been replaced recently, such as just before this problem began?

Have you checked all the exhaust T/Cs to ensure they are properly installed in the radiation shields, that the T/C tips are not touching any portion of the radiation shield, and that the T/Cs are inserted to the proper depth? There is usually a note on the exhaust T/C arrangement drawing that describes how to install exhaust T/Cs, and I believe it says to insert the T/C until it bottoms out in the radiation (the T/C touches the radiation shield), then pull the T/C back some amount (I can't recall the distance), and then set the ferrule on the sheath with the nut. I've seen some T/Cs come from the vendor which have the ferrules set improperly; the ferrules can be cut off with a small die grinder if necessary as long as the sheath isn't damaged when doing so.

I've seen exhaust T/C tips bent over in the radiation shields by labor working in the exhaust area. For what reason, who knows, but it might be "exciting" to push the T/C tips by inserting one's finger into the radiation shield.

I've also seen loose metal sheets in the exhaust area cause problems with air flows. Rusted exhaust diffusers can also cause similar problem. Has anyone inspected the exhaust area for unusual problems?

Sometimes, air flows in the exhaust can cause problems at certain loads. If the unit can be loaded above 83 MW, do the spreads get worse or better? What is the IGV angle when the spreads are highest?

If, after a maintenance outage, the seals between the transition pieces (in the combustor/combustion wrapper) are not properly installed, then air leaks can cause high spreads. If you change reasonably flow-matched nozzles and the spread doesn't move, this could be an indication of such a problem. (See how installing flow-matched nozzles can be an even bigger help when troubleshooting spread problems?)

Cracked combustion liners and transition pieces allowing excess air into the combustor gas path can also cause similar problems. If you change reasonably flow-matched nozzles and the spread doesn't move, this could be an indication of such a problem.

But, when you post a problem like this you must provide more information about the circumstances and where the spread is and if it moves when you change nozzles, etc.

This problem is likely not controls-related, and the only reason any assistance is being offered is because we're trying to teach people how to post problems and provide sufficient information when they do post a controls-related problem.

The people contributing to this site *can not* intuit any of the conditions or results of any troubleshooting or problems that occur at your site.

And, a considerable amount of time is spent trying to cover as many possible scenarios as possible. Sometimes we get get feedback, most times we don't. Please provide some answers to the above questions, and if you resolve the problem please let us know what was done and how you resolved your problem.

Please try to provide more information the next time you post.

 

First I need to know the reason why you have changed the fuel nozzles recently. Second I need to know the new nozzles mounted on the machine is calibrated.

Jais
0097150 2548904