Ha ha Ethanol.

[bc.gold 3,403]

This short video demonstrates how to test your gasoline for ethanol content but on the other hand also explains how to remove ethanol.

 

 

[lynnmor 7,354]

Since the refiners depend on ethanol to raise the octane of their crappy gasoline, you need to know how much you can remove before the octane is too low.  My guess is that very little can be removed before the gasoline becomes unusable.

[Beap52 867]

This modern gas sure plays havoc with my '71 El Camino.  Cold starts, it pops right off.  Cool to warm weather no problems but when we hit 90 degrees  like the past couple of days, if it sits and idles awhile, problems arise.  I guess the gas heats up in the fuel lines and the excess pressure overwhelms the needle valve in the carburetor and she loads up-with fuel dribbling out the side of the carburetor onto the outside of the intake manifold.  I took the air cleaner off and can hear the fuel boiling inside the intake manifold.  Once excess gas evaporates, it'll start up and run fine, just don't let it heat up idling.  I don't remember having this problem until the past 3 years or so and it's only happened two or three times--which is too many--especially when wife is driving like she was yesterday.  I may try burning premium gas-which is suppose to be ethanol free.  It seems that ethanol gas and preminum when sitting in hot weather or even in sunshine, side by side in plastic gas cans that the ethanol can will swell considerably more than premium.

 

It is a stock 350, 2 bbl.  Still using breaker points. I've tried to keep it a original as I can.  There is a 1/4 inch thick gasket between intake manifold and the carb.

[wallfish 17,083]

18 hours ago, lynnmor said:

Since the refiners depend on ethanol to raise the octane of their crappy gasoline, you need to know how much you can remove before the octane is too low.  My guess is that very little can be removed before the gasoline becomes unusable.

There is (or at least was) an oil based octane booster back when I was searching/learning about this stuff a while ago.

Funny was a video where the guy did all this crazy stuff to remove the ethanol from the gas and then at the end explains how it now needs an octane booster. Then proceeds to pour octane booster in it not realizing it's made of alcohol. Commenters really let'm have it too.

[wh500special 2,237]

i didn't watch the video.  I presume he's adding water to gasoline to try and extract the alcohol into a water phase at the bottom of the funnel. 

 

I do like reference to the separatory funnel though.  Great piece of lab glassware.

 

It's a very straighforward estimation process to determine the octane reduction when you take out the ethanol:

 

Since we are looking at octane level over a fairly small range (say 87-93) you can pretty well assume that the apparent octane level as a function of percent alcohol in the mix is going to be linear.  100% Ethanol has an octane level of around 100-115.  I'll use 110 as the baseline.  Typical base formulation regular grade gasoline for non-mountainous areas has an octane level of 87 but I suppose the refiners may drop the octane number slightly when the fuel is intended to be blended with ethanol as a booster.

 

If you were to blend 87 octane gas with 10 octane ethanol at a 50/50 mix you'd get an overall octane of about 99.  (87+110)/2 = 99.

 

If you blend at 10% ethanol to 90% gasoline you'd end up at about 89 in the blend.  0.9(87)+0.1(110)=89.

 

Working backwards from a pump posted value of 87 octane gasohol with a 10% ethanol content, then the base gasoline started life as 84 octane.  0.9(x)+0.1(110)=87 so   x=84

 

So if you remove the alcohol by extraction that's about where you end up.  That's probably too low for a lot of engines to like.

 

if this was higher octane fuel - say pump posted 91 octane -  with the ethanol in it and you extract the alcohol, then you'd land at about 89 octane when you're done.  That ought to work just fine in almost anything.

 

This all assumes, of course, that the ethanol was the only thing the blenders added as a means of boosting the octane number.  if they added other stuff too, then the reductions when you extract the alcohol will be somewhat less.

 

And what are you going to do with that water/alcohol/whoknowswhatelse mix that's left over?  You can be sure it's not just alcohol and water that can be responsibly dumped.  The safest thing to do with it would probably be to blend it in with a large quantity of gasoline and burn it .

 

Steve

[dcrage 628]

On 6/5/2023 at 8:41 AM, wh500special said:

i didn't watch the video.  I presume he's adding water to gasoline to try and extract the alcohol into a water phase at the bottom of the funnel. 

 

I do like reference to the separatory funnel though.  Great piece of lab glassware.

 

It's a very straighforward estimation process to determine the octane reduction when you take out the ethanol:

 

Since we are looking at octane level over a fairly small range (say 87-93) you can pretty well assume that the apparent octane level as a function of percent alcohol in the mix is going to be linear.  100% Ethanol has an octane level of around 100-115.  I'll use 110 as the baseline.  Typical base formulation regular grade gasoline for non-mountainous areas has an octane level of 87 but I suppose the refiners may drop the octane number slightly when the fuel is intended to be blended with ethanol as a booster.

 

If you were to blend 87 octane gas with 10 octane ethanol at a 50/50 mix you'd get an overall octane of about 99.  (87+110)/2 = 99.

 

If you blend at 10% ethanol to 90% gasoline you'd end up at about 89 in the blend.  0.9(87)+0.1(110)=89.

 

Working backwards from a pump posted value of 87 octane gasohol with a 10% ethanol content, then the base gasoline started life as 84 octane.  0.9(x)+0.1(110)=87 so   x=84

 

So if you remove the alcohol by extraction that's about where you end up.  That's probably too low for a lot of engines to like.

 

if this was higher octane fuel - say pump posted 91 octane -  with the ethanol in it and you extract the alcohol, then you'd land at about 89 octane when you're done.  That ought to work just fine in almost anything.

 

This all assumes, of course, that the ethanol was the only thing the blenders added as a means of boosting the octane number.  if they added other stuff too, then the reductions when you extract the alcohol will be somewhat less.

 

And what are you going to do with that water/alcohol/whoknowswhatelse mix that's left over?  You can be sure it's not just alcohol and water that can be responsibly dumped.  The safest thing to do with it would probably be to blend it in with a large quantity of gasoline and burn it .

 

Steve

Steve - Do you know what the relative solubility is for ethanol in gas versus water. I am not sure that water would come close to quantitatively stripping ethanol out of gas. I don’t know that it doesn’t but the ethanol preference for water would need to be 100(?)X bigger than for gas for this to be a good technique. 

[wh500special 2,237]

I don’t.  
 

And I’m not much of an expert on solubility in general. I always worked with systems that were already characterized and for which someone else had generated data.  

 

But not being an expert has never shut me up before…

 

I would think that the polar end of the ethanol molecule would have greater relative affinity for the surrounding water than would the non-polar end for the non-polar mix of stuff that makes up gasoline.  I base this guess on the high potency of hydrogen bonding in alcohols and water that gives them their almost magical properties of high boiling points, surface tension, and tendency to form azeotropes. 
 

So I’d surmise that the water would preferentially wash out the ethanol from the gasoline. 
 

But since gas is a mixture of a wide array of miscellaneous hydrocarbons - probably including a variety of other alcohols and things that would have some polarity like carbonyl and ester groups  - the water probably extracts them too during the wash.  Which would throw off the quantitative aspect of the water experiment. 
 

excellent point.  

Edited June 8, 2023 by wh500special

[wh500special 2,237]

Funny coincidence…

 

Autocorrect filled in carbonyl when I meant to type - and apparently misspelled -carboxyl.  That would be another polar group that probably shows up in gas. 
 

😂 

 

Steve