OT: Why do you think there is water in the ethanol that gas stations sell?

What I've heard about it is that water and ethanol mix in an extreme range of proportions, and gasoline and ethanol do, too. But when there is more than 3% or 4% water in the ethanol, it won't mix with gasoline.

So a strong shot of ethanol will absorb water in your gas tank, but if there's too much water, the resulting solution won't mix with the gas. And gas/ethanol mixtures that pick up too much water will separate the gas and the ethanol.

Or so I've read.

There WILL be water in your gas, with or without ethanol. Anhydrous ethanol is pretty expensive to make, it forms an azeotrope around about 96-97%(too lazy to look it up), which means you can't get the anhydrous stuff by plain distillation. It's pretty expensive to get the rest of the water out by other means, so they don't for gasahol. So what you're getting already has a few percent in it, plus whatever the ethanol picks up in storage and transport and it WILL do that. Then the gas itself will dissolve a few percent of water, always present in the storage tanks because of condensation. I had a 2 gallon container of gasahol that was exposed to -6 temps, it had a silver-dollar-sized slug of ice in the bottom when I drained it.

Gas additives, like Heet, mostly have methanol in them, much easier to get anhydrous and not too corrosive in small volumes.

Trinary mixtures can get some fairly strange results(non-intuitive, anyway), pure ethanol can mix with gasoline, but if water is present, it knocks solubility down and the excess drops to the bottom, conveniently where the gas pump intake resides. But water, sans gas, will mix in any proportion with ethanol. So if the service station hasn't drained water in awhile, someday you may be sucking a water- ethanol mix one cold morning. Solubilities also change with temperature.

Stan

"dry" ethanol does not stay dry when exposed to air with moisture in it - ethanol has a great affinity for water.

Id does, and that is the problem. It absorbs the water and mixes it with the gasoline.

That is one sourse - but the same thing happens in the distribution tank.

When more water is absorbed than the ethanol can hold at a given temperature, it "falls out". It is called Phase Separation. Ethanol holds more water when warm than when cold.

Add a bit more water, so in effect the hooch is only 60 proof, and you will likely see a difference. If not, put it in the refrigerator.

neet ethanol has just over half the calorific density per unit weight of gasoline. With the SG of both ethanol and gasoline being very close to 0.78 that means the energy density of ethanol is roughly hald that of gasoline. HOWEVER, IF ethanol can hold 50% water at a given temperature and pressure, then the ethanol/water portion of the fuel has only 1/4 the energy density of gasoline

The label on one of my single malt bottles said that when you add water, or let a poured drink stand, it will become slightly cloudy, which is natural. That would be the phase separation. I've seen it, although poured drinks don't always last that long.

Pete Keillor

I run 91 premium pump gas in my airplane. The gas has somewhere between 0%-10% ethanol in it. I drain a sample from the lowest part of the fuel system and check it every time I fly.

I have never seen any water in it. I'm certain that there is some water absorbed by the ethanol, but never enough to separate out.

Hold on, non-gasohol gasoline doesn't absorb water.

Gasohol with shall we say, dry ethanol, can absorb some water.

Someone get out your graduated cylinder and start adding water to a volume of gasohol until the mixture won't take anymore water and get back to us with the numbers.

Wes

-- "Additionally as a security officer, I carry a gun to protect government officials but my life isn't worth protecting at home in their eyes." Dick Anthony Heller

Isn't that exactly what it says above?

Yes it does - a small amount, but some.. In the range of 0.0175 grams watter per 100 grams of gasoline, or

That is roughly 1/2 gram per gallon.

The generally accepted numbers for E10 gasoline are maximum .5% at standard atmosphere (72F at sea level) - or 3.8 teaspoons per gallon. (18.7 grams) which is roughly 36 times as much as clear gasoline can hold.

Other sources state E10 holds 50 times as much water as non-oxygenated gasoline.

At higher temperatures this is increased marginally, and at cooler temperatures this capacity drops.

I wonder why there is ethanal in gasoline to begin with?

The corn lobby.

yepper!

WE HAVE A WINNER!!!

If there is a technical reason, I think it's job is to replace tetraethyl lead in order to slow down the burn and reduce or eliminate predetonation or "pinging". But I don't know if you need nearly as much as 10% to do that job.

Pete Stanaitis

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Buerste wrote:

spaco fired this volley in news:geSdnceSms9MiODRnZ2dnUVZ snipped-for-privacy@bright.net:

The stated reason is to add an "oxygenated fuel" in an effort to lower "emissions"; but whatever goes in must come out, so it's only going to have the effect of lowering _certain_ emissions in favor of increasing others. Primarily it is NOx and CO they're going after with ETOH.

We have one fuel station near us that sells "non-ethanol gasoline" as a specialty (not racing fuel, but not sold as regular highway gasoline, either).

My old '96 LeSabre gets 28mpg on "straight" summer-mix regular. It gets

- or almost a 25% increase in fuel consumption and total emissions.

Less ozone-attacking and greenhouse gasses are produced, if you believe the government test figures -- but I think they base that on the expected small reduction in economy of only 5-6%. Maybe re-chipping the LeSabre would help.

LLoyd

Thank you for some numbers I can try to keep in my head.

Wes

Clair says .63 oz of water will mix with 128 oz of E10 gasohol. Okay, still thinking .63 oz into 12.8 oz of ethanol. 4.+% . Okay, I got it, you got it. It was past my bed time last night.

Wes

-- "Additionally as a security officer, I carry a gun to protect government officials but my life isn't worth protecting at home in their eyes." Dick Anthony Heller

I think the stated purpose was to reduce dependance on foreign oil. So, they drive tractors up and down the field to plant, and harves. More fuel to haul the corn to the distillery. More fuel to heat the mash to get the alcohol out. And then more fuel to haul the alcohol to the gasoline factory.

They would be better off, to encourage drilling and oil production on US soil, and off the coasts. If that really is the agenda, of course.

spaco on Mon, 30 Aug 2010 12:39:40 -0500 typed in rec.crafts.metalworking the following:

More like "Do I see any ethanol separated from the water?" No. H20 and C2H6O "like" each other. Pour both in a sample of gasoline, and like frat boys in a mixer, they'll 'hang out together'. Of course, how well they do that is also dependent on concentration and temperature, and all that chemistry stuff.

Ayup.

One of the reasons for the deforestation of the Amazon basin was to plant sugar cane to make fuel ethanol, Brazil not having much in the way of local petroleum sources.

With 20% lower energy, don't we burn 20% more fuel to get there?