Gas Line Antifreeze?

[y_p_w]

Originally Posted By: kschachn

There is no such thing as water saturated ethanol. Water is completely miscible in ethanol. Once again the only determining factor would be the concentration of alcohol in the gasoline. The guy keeps talking about alcohols being saturated with water which is meaningless.

Water could be saturated to the point where the ethanol content isn't enough that the blend of water/ethanol/gasoline is miscible.

Then there's phase separation. I've personally seen that in a lawn mower. I suppose that's more likely because the tank isn't sealed like a modern vehicle. I wasn't quite sure how to fix it either.

 

[SHOZ]

I have a Briggs motor on a pressure washer. It pulls the gas out of the tank and then into a small cavity on top of the tank for the carb to draw on. It is horrible for accumulating water that the ethanol has absorbed from the air.

I tried straight ethanol, straight isopropanol and straight methanol. None would get the mix with the water and remove it completely. I have to disassemble the tank completely to get it out.

 

[John_Conrad]

The way i understand the phase separation, is that it can occur as an ethanol & water mixture or depending on the temperatures and water content, a separate water only layer can form along with the gasoline.

So one could encounter gasoline, and a phase separated ethanol and water mix.

Or gasoline, a phase separated ethanol and water mix and possibily a third layer of water, if the temps dropped enough while water content was excess and the ethanol was not able to hold it all due to the temp drop.

I am not edumucated in this field so I put this out for my learning curve if not so. thanks.

 

[SHOZ]

Once the ethanol has absorbed enough water both it and the water drop out of the gasoline mixture. No significant amount of either is left behind in the original mix.

 

[kschachn]

That's absolutely not true for a given temperature. Did you look at that paper I linked?

It's no different really than adding salt to water. Once it is saturated no more will dissolve, but it doesn't precipitate out of solution.

Originally Posted By: SHOZ
Once the ethanol has absorbed enough water both it and the water drop out of the gasoline mixture. No significant amount of either is left behind in the original mix.

 

[SHOZ]

I took 500 mL of E10 gas. Added 500 mL of water. Ended up with 450 mL of gas and 550 mL of water and ethanol sitting on the bottom. This happened almost instantaneously.

 

[kschachn]

Except that the ETOH will not separate, why would it? It is soluble in the gasoline while the water (past the solubility shown in that paper I posted) is not. Water will separate if the temperature falls or there is more water than the concentration of ETOH in gasoline can solubilize.

Originally Posted By: John_Conrad
The way i understand the phase separation, is that it can occur as an ethanol & water mixture or depending on the temperatures and water content, a separate water only layer can form along with the gasoline.

So one could encounter gasoline, and a phase separated ethanol and water mix.

Or gasoline, a phase separated ethanol and water mix and possibily a third layer of water, if the temps dropped enough while water content was excess and the ethanol was not able to hold it all due to the temp drop.

I am not edumucated in this field so I put this out for my learning curve if not so. thanks.

 

[John_Conrad]

I agree with what you are saying kschachn, although i may not have written so everyone could understand it.

Is it not possible that all of the alcohol could be separated from the gasoline given the right amount of water and temp? Leaving you with the original low octane gasoline and the (ethanol water mix) phase separation...thanks for your help.

 

[tony1679]

Originally Posted By: SHOZ
I took 500 mL of E10 gas. Added 500 mL of water. Ended up with 450 mL of gas and 550 mL of water and ethanol sitting on the bottom. This happened almost instantaneously.

Exactly! This is what i was trying to get at. 500mL ×.1 (10% Ethanol) = 50mL. Which means the ethanol has mixed with the water and made the "water" level RISE (ethanol "fell" out of gasoline mixture). I am not a scientist or chemist, but I am good at math! Lol

 

[addyguy]

Whether it is necessary or not, I will tell you that gas line antifreeze sells very well in Canada in the winter.