Mogas -2.5% alcohol in all forecourt petrol from April.

[Maoraigh1]

On Tuesday 25 March, on P5 of the Aberdeen "Press and Journal" it is stated:
" From next month, biofuels are to be used to partially power every vehicle in the country. Under the Renewable Transport Fuels Obligation they will have to comprise at least 2.5% of fuel at the pump.
"Next month" means April. The biofuel added to petrol is ethanol(alcohol).

[soay]

Unless the government sees sense, before it's too late:

Top scientists warn against rush to biofuel (http://www.guardian.co.uk/environment/2008/mar/25/biofuels.energy1)

[Rod1]

“The biofuel added to petrol is ethanol(alcohol)”

This is not correct. Bio petrol can use ETBE which contains not one drop of any form of alcohol.

Rod1

[soay]

ETBE ... contains not one drop of any form of alcohol.
ETBE is synthesized by mixing ethanol and isobutylene and reacting them with heat over a catalyst, according to wikipedia (http://en.wikipedia.org/wiki/ETBE).

[Rod1]

Correct, the reaction completely consumes all the ethanol and non is left in the fuel. The resultant bio petrol does not have any of the bad properties associated with fuel containing ethanol. Your 2.5% alcohol in fuel is therefore wrong and helps perpetuate the myth that all Mogas contains alcohol.

Rod1

[Mariner9]

Rod's comments are correct regarding ETBE, but this whole thread is based on an incorrect premise.

Under the Renewable Transport Fuels Obligation they will have to comprise at least 2.5% of fuel at the pump.

That is an incorrect interpretation of RTFO.

RTFO obliges Fuel companies to supply 2.5% transport fuels from renewable sources. This does not mean that 2.5% biocontent will automatically be added to all fuels.

At the moment, many fuel companies intend to meet their current obligation primarily through biodiesel to which 5% FAME -(a biofuel) can be added under current specs, and not biogasoline which is technically more difficult to produce. There is also a "get out" clause available which enable fuel co's to purchase carbon credits if the obligation is not met (although to be fair, commercial pressures will most likely make the companies strive to avoid this option)

No doubt the situation will change as things develop over the next 2 years, but there is no need to abandon Mogas as an aviation fuel just yet. Keep doing the prescribed alcohol test - if it passes use the fuel.

[Maoraigh1]

Thanks Mariner and Rod.
I had hoped someone with industry information would respond.

[BackPacker]

Keep doing the prescribed alcohol test - if it passes use the fuel.

The only "prescribed" alcohol test I know of for GA is where you put a measured amount of water and a measured amount of fuel into a container. Stir or shake vigorously, let it settle and see if the "apparent" fuel/water ratio has changed.

Sounds good in theory, but with a potential alcohol content of 2.5%, or possibly up to 10% in some places, it doesn't come across as a huge potential change in the ratio. Plus you need a see-through container that can be sealed properly and is resistant against everything that may be added to the fuel, and a very accurate way to either measure the fuel beforehand, or write on the container to see what the start and end levels are.

Does anybody have practical experience using this method? Particularly of course if you actually found alcohol so you've proven the method to work. Any tips? What sort of container do you use?

[GOLF_BRAVO_ZULU]

Any of you chaps remember this stuff?

http://www.advertisingantiques.co.uk/Portals/19/VizGallery2749/1805.jpg

[Maoraigh1]

I use a glass tube, 5mm diameter, melted to seal one end. A brush bristle is araldited about 25mm from the bottom. The tube is about 200mm long. I use a thinner glass tube to fill it to the mark with water. I then fill it up with petrol. My finger seals the end. I invert several times. The alcohol from ALL the petrol should go into the water. (Well, some of the alcohol from all of the petrol.) I've only once got a small rise in water level. I repeated the test several times, then put the petrol in my car.
At least I can honestly face the AAIB and Insurance company if I survive an engine failure.

[BackPacker]

Maoraigh, looks good. Thanks. Were your results consistent from one test to the next (with the same batch of fuel)? In other words, do you consider it consistent enough to accurately detect ethanol? Not just for the insurance and AAIB, but for your loved ones as well?

And the one time you got a positive result, did you by any chance follow it up with the supplier and confirmed that there was indeed ethanol added, and what percentage?

[Mariner9]

For Backpacker and everyone:

The official procedure is to use ASTM method D1094 or the equivalent IP289. In this method, 80 ml of fuel sample is shaken with 20ml of water (Well actually, its a "phosphate buffer solution" which is water with K2HPO4 and KH2PO4 but pure (distilled ideally) water will do for a field test) in a graduated glass cylinder for 2 minutes at a rate of 2-3 strokes per second.

The water volume is measured before and after the test to the nearest 0.5ml. The maximum increase to meet Avgas specs is a 2ml increase, which, if all water miscible components seperated into the water phase, would equate to 2.5%.

Therefore, even if a Mogas contained 2.5% ethanol, and that all ethanol seperated into the water phase (which it wont), then the fuel would still be within the limits specified for Avgas and hence suitable for use as an aviation fuel. :8

[Maoraigh1]

I usually use Tesco for fuel. The one sample that failed was a one-off purchase (Somerfield??). I would never query it with a supplier -the effect I would expect would be for them to ban me from filling jerrycans. They don't know it's for an aeroplane.
Apart from that one instance, I usually do one check only.
Mariner's proper method is interesting. I suspect the right proportions
petrol:water might be O.K.
I'll mention a proper measuring cylinder to the group.
That 2.5% alcohol is acceptable is interesting.

[Mariner9]

Technically, the CAA rules state that Mogas should not contain any alcohol, not that it should pass the test. However if it passes the test, there is no way you could know if the fuel contained alcohol or not.

Incidentally, the max alcohol allowed under the current Mogas specs is 5% not 2.5%. However, the reality is that a field test would be unlikely to detect 5% alcohol - its only really possible for a trained chemist working in the controlled conditions of a petroleum laboratory.

If you really want to avoid alcohol in fuel altogether, Tesco's may not be the best choice