ISO 2314:ôGas turbines: acceptance testsö 1

[engy74]

I have to define the performances of a gas turbine fed by natural gas for a new plant.
I need then to define the tolerances of the guaranteed values (electrical power and gas consumption) and of the instruments to use to measure these values.
Could you indicate me, please, which is the norm that rule the acceptance of the gas turbine defining these values?
I remember this: I have to define the performances of a gas turbine fed by natural gas for a new plant.
I need then to define the tolerances of the guaranteed values (electrical power and gas consumption) and of the instruments to use to measure these values.
Could you indicate me, please, which is the norm that rule the acceptance of the gas turbine defining these values?
I remember this: ISO 2314: 1989 “Gas turbines: acceptance tests”: could you confirm please?
In case, could you indicate me if there are other norms, and where can I find them (possible free)?
Also an indication about the possibility to find (free) the ISO 2314 would be appreciated.
Best regards and thank You.
Engy 74

 

[TD2K]

I would first review the engineering and purchasing documents for this unit, is there anything in those documents that specifies how the unit's output and rating will be defined and evaluated?

If those documents state 'these are the terms for equipment evaluation', you might as well start there. Results from other methods if they indicate a problem aren't going to be accepted by the vendor as they as not per the terms of the contract.

 

[engy74]

Thank You,TD2K,but the actual situazion is this (with more details)I'm in the proposal phase, so there isn't a contract between my Company and the GT supplier: I have in my hand only the documents produced by my GT supplier, in which are indicated the tolerances on the values of natural gas consumption (the electrical power is guarantedd without tolerances ).
Clearly, this value don't consider the tolerances of the measurement devices (Coriolis devices on the natural gas, for istance).
Now it's my duty, as potenzial contractor to the final Customer, define for the Customer the other tolerances (on the measurement instruments) to evaluate the performances of the machine.
For the performing test of two natural gas engines I have installed I referred to ISO 8528-1, but, as I haven't experiences in GT fields, I need help to find something similar to the rules for engines.
Bye
Engy 74

 

[pmover]

what you need to establish with supplier are site design conditions (winter, summer, & normal conditions), fuel gas composition (if natural gas) and include any variations of fuel gas (i.e. different compositions if applicable), and the guarantee turbine output power for each site design condition.

Another reference is API-616. i do not have my copy with me, but if requested, within the next day or so, i can get it and provide you essential guarantee information.

gt suppliers will gladly furnish you with preliminary performance data upon request.

in terms of performance tolerance, the test standard (iso or API) will provide you the guidelines. be certain that the purchase requisition/contract has performance parameters included.

i also highly recommend that you familiarize yourself with the performance calcs in correcting gt performance to some ambient condition.

sounds like a fun project!
good luck!
-pmover

 

[pmover]

whoops! forgot...

as far as a "back-up" copy of the iso or api std, good luck in trying to obtain one. i highly recommend that you -purchase one yourself. it will be worth every penny!
-pmover

 

[1969grad]

See ASME power test code for gas turbines. I think it is PT-10.

Nothing is free from ASME or API. You have to pay for it. If someone did try to put publications from these organizations on the internet then they would be in violation of the copywrite laws.

 

[engy74]

Thank You very much,PM over...with reference to reference conditions for the performances of the GTs, I don't have troubles: average ambient temperature, site altitude, pressure losses at inlet / outlet, and so on are parameters well known and well defined; so this isn't a problem (and I have checked, for the various situations, the performance of the machine...)
Now the things to defines are the measurement devices: to tell my Customer (or potential Customer: this is only a proposal...) : "the values are given with tolerances of xxx % "PLUS" the tolerances of the measurement devices (for istance 5%)."
the tolerances of the values guaranteed by my GT supplier are known for both the gas consumption and electrical power.
It remains to indicate the values of the tolerances of the instruments...so, if You are so kind to send give me some indication by API 616 it would be a good start...
In the worst case I can ask my Supplier some suggestions: but, don't to appear disinformated about these things, as You understand, I'd prefer avoid to ask...
Best regards,
Engy 74

 

[TheTestEngineer]

Dear Engy74.

I serve on the ASME PTC-22 committee for gas turbine testing. I should be able to help. I have presented papers on this topic. Many buyers give away a lot in their contracts.

First, some definitions:
"Test tolerances" is purely a commercial item. View it as a reduction in the guarantee. For example, suppose you get quotes for 100 MW with no test tolerance, 101 MW with 1% test tolerance and 103 MW with 3% test tolerance. These three are identical. Each will begin to pay liquidated damages if the test result is below 100 MW.

Test Result
The test result is adjusted for instrument calibrations and for corrections to the guarantee basis only. The test result is the most probable actual value. There will be a 50% probability that the actual value is above the test result and a 50% probability that the actual value will be below the test result. If you allow test tolerance equal to test uncertainty, then you are accepting a turbine that may have been proven with 97.5% certainty that it failed to meet the guarantees.

Uncertainty.
This is the width of the probability distribution that includes the 95% confidence interval. In other words, it is equal to 2 standard deviations, assuming a bell curve distribution, of the possible test results around the actual true value.

Test Uncertainty Calculation
Test uncertainty is calculated as the root sum square of the individual measurement uncertainties. Test uncertainty = sqrt (sum of (each measurement uncertainty * each sensitivity)^2), in other words, the root sum square (RSS) or the hypotenuse of a multidimensional triangle.

Individual Measurement Uncertainties
Measurement uncertainties include the instrument accuracy, repeatability, and the spatial variation. For example, suppose you put a perfect RTD in the gas turbine inlet.
Since the variation from one location in the inlet and another can differ by 3F, we might estimate your uncertainty as +/-3F. But if you install 9 RTDs, then the uncertainty may be judged to be 0.5F.

Measurement Sensitivities
Measurement sensitivities are the slopes of the correction curves. They can also be found by calculating corrected heat rate, for example. Then change power by 1%. Heat rate changes 1%. So the sensitivity is 1%/1%.

GOAL
With good selection of instruments, you should be able to get power within +/-0.4% and heat rate within 0.8%. The uncertainty analysis will tell you the quality of the test and will tell you which instruments are most important, and where you should spend your instrument and calibration dollars.

I hope this helps.
TheTestEngineer

 

[engy74]

Thank You very much,TestEngineer.
Your reply was one of the most interesting and complete I have received... now I'd like to understand if there is a norm which indicates the quality of instruments and therefore their accuracy...so I will be able to indicate a value (maximum, for istance) with reference to which define heat reat and power of the machine I have proposed.
Thank You again and best regards.
Engy 74

 

[msonnet]

Try this one out, gives you a complete list of standards, even a schematic of where to put the instrumentation and their precision.

http://www.tuv-energy.co.uk/Download/CIMAC98.PDF

Hope it helps

 

[TheTestEngineer]

Dear engy74,

I think msonnet has answered your question very well by providing the paper by TUV. I marked his posting as a helpful post.
Best Regards,

 

[engy74]

Thanks everyone,but it's impossible for me(and I don't know why) to download the file...if You can, You can send it at viaggiatore74@hotmail.com.Best regards, Engy 74