Methanol - How long does it last? 1

[DMan1]

Hello,

I've got some methanol (M100) that I have been storing in plastic 5 gallon pails with the sealed lid (o-ring). Storage time has been about 3 years. Storage area is usually dark and temperatures have swung seasonally from about 0 deg F to 85 deg F.

Now its time to use some of the methanol. Is it still "good"?

More importantly, what does "good" mean in this context? Octane rating? Volatility? Not sure what characteristic I need to be concerned about.

Intended use is for automotive fuel.

Thanks in advance..

Denis



Denis Kefallinos

 

[franzh]

Recognize that as soon as the container is opened, its shelf life is over. It will absorb moisture from the atmosphere.
Use it in small concentrations if you are going to use it as a gasoline additive, any concentrations over 10% will initiate component corrosion. The BTU contect of neat methanol is only about half of gasoline.
Use face mask, eye protection, rubber gloves, etc. Do not spill any of it as it is groundwater soluable. Skin will absorb it and it may cause headaches or dizziness if prolonged contact with liquid or vapor. It's toxic if you ingest it.

Franz

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[DMan1]

Thanks for the safety tips.

So what exactly do you mean by shelf life is over? How much moisture does it absorb? Instantaneously the entire batch is bad? I've opened these containers before and subsequently used the fuel, so I don't understand what you mean.

Denis Kefallinos

 

[franzh]

The fuel absorbs water, and it depends on the ambient humidity present. 100% (neat) methanol has no water, but it does absorb some any time the container is opened, again, in varying amounts. There is no hard and fast rule to determine how saturated the fuel is, one method is to take a specific gravity test, a GC-FIC test, or a water paste test. All in all, Methanol is my least favorite fuel.

Franz

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[DMan1]

Excellent, thank you.

Are there any other factors or properties that degrade over time?

Denis Kefallinos

 

[patprimmer]

Methanol does not normally degrade over time. It simply absorbs water(as Franz has stated) from the atmosphere.

It will still absorb it very slowly if stored in a plastic container as plastics are not 100% impermeable to water vapour.

The time it takes to absorb water is anyones guess as it depends on temperature, humidity, air gap in the top of the container, quality of seals, material from which the container is made, and for plastic containers it depends on the wall thickness.

As Franz says, specific gravity will indicate water content.

You can use methanol with some moisture in it (in fact it always does have some as it starts to absorb it on any contact with any air, including the small amount of air in the top of the drum).

When you know the moisture content, you can correct the jets to compensate for water content.

For good quality (read pure dry) methanol, it will normally be less than 0.5% water when you use it, if you keep it stored in full, metal, well sealed drums and only add it to the tank within an hour or two of use.

If your stuff has say 5% water, increase jet cross sectional area by 5% vs correct jets for good methanol.

Regards

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[DMan1]

Excellent once again. Thank you

Denis Kefallinos

 

[tbuelna]

It has been documented that several gallons of methanol, when stored in the fuel cell of a top fuel dragster, will last approximately 4.6 seconds

 

[patprimmer]

We use special long life methanol in our door car. If there is 12 litres in the tank it lasts about 7.8 seconds.

Regards

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