03-14-2014 01:35 PM
The fuel correction factor will be different due to the condition of each engine. One engine could have more wear than the other. Excessive wear on the turbo charger, blowby, etc. Our 3520s are never at the same fuel correction level. 8.2% O2 seems very high compared to our sites. Typical we run below 2% and have ran up to 5%. The higher the O2 the more probabilty of taking out turbos and cyliner heads upon hard shutdowns. Witnessed this on other makes also. There should be no issue using a 4-20 as long as it is scaled. Although the engins will run a lower methane number they dont quit like it. So depending on your site it will depend. Tailor it to your site but within specs. You might want 4 at 40% and 20 at 65% really depends on the characteristics at your site.
01-06-2014 07:26 AM
We have 6 engines at a LFG in argentina.
We seted the window for the signal of CH4 level in that way:
LLHV HLHV Use Fuel Quality
MJ/Nm3 MJ/Nm3 MJ/Nm3 Fuel Correction Factor
GE 1 12,5 26,4 20,36 104
GE 2 12 26,8 20,08 106
GE 3 12 27,2 20,79 102
GE 4 12,5 26,8 20,4 100
GE 5 12 27,2 20,24 100
GE 6 13,7 26,5 20,64 100
CH4 Level informed by FSU Landtec 57,1%
this values were found with a O2 around 8.2% and NOx around 140 ppm.
we have 2 questions
- Why the difference in the FCF (Fuel Correction Factor), in some cases the FCF for the engine 2 is 112 and at the same moment for the engine 6 is 100.
- Is ok that we send a signal 4..20 mA with the level of methane or it need a conversion to other value.