Benchmarking for 9FA

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Thread Starter

mkgupta

I am looking from my colleagues who can help in CCPP benchmark.
Kindly share your experience in bench marking of CCPP having block configuration of 1:1:1 for plant availability, Plant heat rate, forced outage, & auxiliary consumption.
 
mkgupta,

I'm not familiar with a 1:1:1 configuration; can you please explain?

Benchmarking 9FAs, in particular, should only be done when you are absolutely certain that the configurations of the machines being used in the project are all the same--that is, that they all have the same compressor components (flared vs. non-flared; snowflake vs. non-snowflake; etc.). There are sites in some places in Southeast Asia with multiple 9FA turbines on the same site which have wildly differing configurations on the same site.

Also, care must be taken to ensure that the data-gathering methods are similar on all sites. And, that the calibration of the equipment used at all sites is within specification. And that all data is taken at similar operating conditions (specifically, when the grid frequency is stable and at rated). One of the biggest complaints I hear about 9FA turbines in Southeast Asia is that they don't always produce rated power output. And, after a few questions it always comes out that these periods of low power output occur when the grid frequency is below rated--sometimes significantly below rated and for extended periods of time. No gas turbine--not even a 9FA--can produce rated power during off-frequency conditions, and expecting otherwise is not reasonable. (Of course, neither is forgetting to mention that these low output periods coincide directly with off-frequency operation (reasonable, that is).)

Trying to compare availability and reliability (forced outages) is also fraught with problems because too many times the reasons for the forced outages are never really understood or are "massaged" to protect the guilty. There is just too much room for subjective reasoning in some of these methods and in "justifying"--or not--some of the reasons for forced outages. For example, most electro-hydraulic servo-valve "failures" are attributed to the servo-valve, <b>NOT</b> to poor oil analysis and lack of oil maintenance practices. So, which is it: A servo-valve quality problem, or a maintenance issue? (You don't have to guess which the Maintenance Department thinks it is in almost every case.)

Lastly, the fuel analysis for the fuels used on any site must be used for any benchmarking purpose.

Differences in HRSGs can also cause huge disparities in data.

Benchmarking against other machines at various sites can be useful if the proper methods and comparisons are made, and are done so using similar practices. Otherwise, trying to correct for too many variables can lead to some outlandish results--and conclusions.
 
> I'm not familiar with a 1:1:1 configuration; can you please explain?

I suspect 1:1:1 configurations is Gas Turbine : Generator: Steam Turbine, (or maybe the Steam Turbine is in the middle, but FA's usually have the generator in the middle). More commonly, this is called Single Shaft STAG on GE design installations.
 
otised,

Long time no hear from you; good to have you back!

And, why didn't he just say it was a single-shaft STAG unit? (Rhetorical question--if it is a single-shaft STAG unit. I've been hearing some odd terms used lately for CCPPs (Combined Cycle Power Plants) and I suspect this is another one of those. Maybe.)
 
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