PTC4 corrected efficiency calculation 1

[BINGMD]

When I use PTC 4 to calculate the boiler efficiency, I always perform a tested efficiency calculation and a corrected calculation and then compare the two efficiencies to make sure the difference is below 2% since we always pick a test fuel close to the design fuel.

There is a different opinion. For oil & gas boiler, the natural gas property will not vary much, therefore, no need to take fuel sample and analyze it. So it is ok to use the design fuel analysis directly and only work on a corrected efficiency calculation. Is this acceptable?

Also, is it acceptable to use the measured fuel flow rate in the calculation directly without iteration?

Thanks a lot for your help!
Bing

 

[athomas236]

Are the tests to show compliance with contract guarantees or part of a regular monitoring programme of boiler efficiency?

Regards,

athomas236

 

[BINGMD]

It is the test to show compliance with contract guarantees. Thanks.

 

[athomas236]

In that case I would stay strictly with the requirements of the test code, just in case there are any problems which would allow the contractor to then argue that if the test had been done to the code he would have met the guarantee.

I am reviewing a performance test procedure at the moment with oil being supplied from a refinery local to the plant and no one has even suggested not taking fuel samples for analysis.

Regards,

athomas236

 

[BINGMD]

Good point. Thanks!

 

[BINGMD]

BTW, do you know what method shall I use to take natural gas or oil sample?

 

[athomas236]

For oil, we would take 2 or 3 samples from a drain on the pipe to the burners. The quantity would be 3 times what is needed by the laboratory. One sample would be tested by the contractor , one by the client and one kept by the consultant/owner's engineer for reference.

When I have tested gas fired plant, we had high quality tariff meters that incorporated gas chromography which gave composition and calorific values at 15min intervals, so we used this.

For gas sampling, there may be some ASTM standards.


Regards,

athomas236