miscibility problems of stable and homogeneous mixture of diesel and vegetable oils
Keywords: blends, blend, oil, fuel, gas oil, diesel, viscosity holding risks additive.
This article is intended for all users of pure vegetable oil or rolling mixed frying.
Recently, many users of mixtures GO-HVP found mechanical problems on their injection pump.
The reason: it seems (it is even verified) that the new diesel (major oil brands) contain an additive that allows more good miscibility vegetable oils.
Here is the testimony and the tests of 2 users of pure oil. Click on the photos to enlarge.
1) First testimony: miscibility, viscosity and durability tests carried out in winter (end of 2005) at -2 ° C with new frying oil.
The author compares 3 mixtures (the letters are indicated in the photos):
1) P = 50 50%% oil + oil
2) D = 50 50% +% diesel oil
3) H = pure oil
When we talk about oil, it is actually kerosene used in auxiliary heating stoves (and sold for up to 2 € / L by the way!). It is a product which is situated, at the level of refining, and therefore of "heaviness", between diesel and gasoline. It looks a lot like kerosene.
The oil is a mixture of different new frying oils: rapeseed / palm / sunflower. This is often the case for frying oils, they are sold already mixed!
Results in images after 2 weeks homogeneous mixtures were still nearly -2 ° C.
We can clearly see that the oil has long since reached its cloud point. This haze effect is completely canceled out by kerosene and to a lesser extent by diesel.
Conclusions: the resistance of the mixtures in winter and after 2 weeks is almost complete. The beginning of the freezing of the oil clearly shows that it is very risky to run at 100% oil in cold periods, but the frozen oil once again became perfectly fluid once mixed with the kerosene.
2) Second testimony: miscibility problems with new gas oils (June 2006)
The author shows that the miscibility would no longer be correct with the new diesel! This testimony is currently the only one and will be confirmed later. Tests are in progress, mixture of diesel incompatible with vegetable oil?.
»(…) The fuel has changed in appearance, smell and additives; if you haven't noticed it, know that your diesel is not the same as it was a year ago.
It foams less you will tell me, moreover it is sold with an anti-foam additive, but it has especially become different to try to prevent the additions of vegetable oil.
How, that's another story, still it is that the addition of rapeseed oil (the cheapest and the most used) in the current diesel mixes badly and diesel pumps do not like mixtures non-homogeneous, this creates eddies with variations in pressure and the destruction of the pump becomes a sad reality !!!
4 people have already notified me of serious engine problems (2 destruction of the injection pump, on old cars), so I did a little test (analyzes will follow).
The two vegetable oils that have served to test:
These two oils were bought at a "Discount" super market famous for its low prices (0,85 and 0,89 euros).
Now here is the result of the addition of these two oils in current diesel:
In the left tube has been added rapeseed oil, as we can see the bottom is lighter (Rapeseed) than the top (Gasoil) and in the right tube has been added sunflower oil, miscibility is better but far from perfect!
To accentuate the appearance of the mixture, a slight coloration of the diesel was carried out in the two tubes:
As you can see, the oils do not mix very well in both cases, but mainly in the first tube that received rapeseed oil!
Here is the final result after mixing with the agitator and a little rest:
Conclusion: although I think it is not necessary to conclude, the proof is there (you can check for yourself if you wish), rapeseed oil is to be avoided !!! As for Sunflower oil, only time and tests on your part will tell us; but I recommend you to be careful.
The addition of 1% kerosene in the sunflower / diesel mixture improves the homogenization of the mixture (no effect with rapeseed) ...