HOW TO PREPARE FUEL DILUTION STD. FOR FUEL CALIBRATION BY FTIR METHOD?
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According to the ASTM method E2412
Fuel Dilution standards are to be preapred by Diluting the Fuel in an Aromatic Free base oil.The fuel to be used has to be the original Fuel being used in that engine.
The samples have to be aged at 107 degrees C.with stiring for 30-45 minutes.
The problem with these standards is that if the Fuel in the engine changes then it will not work and a new method has to be prepared for that oil with new fuel.
Fuel Dilution standards are to be preapred by Diluting the Fuel in an Aromatic Free base oil.The fuel to be used has to be the original Fuel being used in that engine.
The samples have to be aged at 107 degrees C.with stiring for 30-45 minutes.
The problem with these standards is that if the Fuel in the engine changes then it will not work and a new method has to be prepared for that oil with new fuel.
Before going further, you should know that GC is the absolute method for the determination of fuel concentration in oil. This method however requires a certain amount of expertise, knowledge and investments.
As for FTIR for fuel detection, the method relies on the presence of aromatic molecules basically coming from the sulfur additive (arround 3050, 1605, 874, 811, 748 cm-1). If low sulfur fuel is analyzed, FTIR won't tell anything. The method was working OK with 5000 ppm sulfur fuel in the past. It is not the same game with 50 ppm and 15 ppm sulfur content. Still, depending on the regions or on fuel batches, sulfur level weren't always be the same thus, method was not precise on a quantitative level.
Flash point can give you an idea, particularly if it is compared to viscosity. That is what I do in my lab but I must say that I analyze oil from our units weekly (close follow-up) and oil is always of the same type.
This method is however not fully reliable due to several possible interference: oil contamination (water, glycol, soot and other), hydrocarbon molecules shear down...etc. There was an interesting article talking about this subject in Practicing oil analysis a couple of months ago.
As for FTIR for fuel detection, the method relies on the presence of aromatic molecules basically coming from the sulfur additive (arround 3050, 1605, 874, 811, 748 cm-1). If low sulfur fuel is analyzed, FTIR won't tell anything. The method was working OK with 5000 ppm sulfur fuel in the past. It is not the same game with 50 ppm and 15 ppm sulfur content. Still, depending on the regions or on fuel batches, sulfur level weren't always be the same thus, method was not precise on a quantitative level.
Flash point can give you an idea, particularly if it is compared to viscosity. That is what I do in my lab but I must say that I analyze oil from our units weekly (close follow-up) and oil is always of the same type.
This method is however not fully reliable due to several possible interference: oil contamination (water, glycol, soot and other), hydrocarbon molecules shear down...etc. There was an interesting article talking about this subject in Practicing oil analysis a couple of months ago.
We were able to develop a chemometric model using quantificiation software to correlate FTIR spectra with results we obtained on the GC. The model was certainly tricky to build and required a large collection of spectra / fuel results and plenty of refinement. We use it to predict when to do an actual fuel determination by GC as the predicted results are not always reliable. However if the viscosity is low and there is predicted fuel, there is almost always fuel dilution and the converse is also true.
To address your initial question, In my experience the only way to obtain standards that are valid is to obtain real samples which contain the desired amount of fuel from engines known to have a fuel dilution issue. I have tried a number of lab techniques to age fuel but have found these to be far from ideal.
To address your initial question, In my experience the only way to obtain standards that are valid is to obtain real samples which contain the desired amount of fuel from engines known to have a fuel dilution issue. I have tried a number of lab techniques to age fuel but have found these to be far from ideal.
