How can 10% ethonal gas produce 73% alcohol? (with water)

  • Thread starter NCBryan
  • Start date
  • #1
NCBryan
8
0
I purchased 22.752 gallons of gasoline containing +- 10% ethanol dispensing it into a 23 gallon gas tank. Then I drove 23 miles (mostly up hill) to a job site. At lunch time I was not able to crank the engine. The symptoms were clear, it was water in the gas. I have a video if you want to see how I did it but long story short I got 2+ gallons of water out of the tank. Well the only place that water could have come from is the gas pump. This had me completely dumbfounded as I know you cannot burn water. Non the less I complained to the pump owner and he said I could not have made it out of the parking lot with that much water in my tank, normally I would agree with that statement but the facts suggest otherwise. After racking my brain for a minute it occurred to me that the gas contained alcohol (ethanol). I know from my Bunsen burner what that means. Fortunately I had the foresight to save the water. I happen to have a separatory funnel a beaker and a hydrometer. So I wanted to see how much alcohol was in the water and was it possible it would partially burn. There is only 10% in the gas so I was thinking it might be as high as 8%. LOL (I did it for you). Then maybe this 8% alcohol and the 50% gas I was getting from the fuel pump would be enough to burn. After checking the alcohol content of the water it came out to 73% (which will burn in my Bunsen burner). Well that blew my mind. Now my problem is going to be, how do I explain to a judge that it is possible for gas containing 10% alcohol to produce water containing 73% alcohol?

It would be so helpful if you can explain it to me.

Thank you.
 

Answers and Replies

  • #2
Borek
Mentor
29,172
3,847
No idea where the judge comes into the discussion from, but try googling "partition coefficient".
 
  • #3
NCBryan
8
0
No idea where the judge comes into the discussion from, but try googling "partition coefficient".
I have to sue the pump owner. He says it is impossible for water to come out of the pump, then he says other cars never made it out of the parking lot when it happen to other customers. Because it is unlikely that the judge is going to be a mechanic or a chemist, I will need to explain it to him in a way he will understand.

Thanks for the tip.
 
  • #4
NCBryan
8
0
That seems to be very close but not exactly what I am looking for because ethanol and gas can mix together.
 
  • #5
Borek
Mentor
29,172
3,847
That seems to be very close but not exactly what I am looking for because ethanol and gas can mix together.

You have water and gas that don't mix, and ethanol that dissolves in both.
 
  • #6
NCBryan
8
0
You have water and gas that don't mix, and ethanol that dissolves in both.
I understand that. I have gas with 10% ethanol, water is added to the gas, water then (In some way??) contains 73% ethanol, how do I explain how the gas that only has 10% ethanol can cause the water to contain 7 times more ethanol. Saying ethanol dissolves in both gas and water in no way explains anything that the judge would not, most likely, already know.

In my mind I understand how it happens I just do not know the terminology to explain it.
 
  • #7
Asymptotic
782
528
Then I drove 23 miles (mostly up hill) to a job site.
What make/model/year is the vehicle? Some manufacturers locate the pick-up tube towards the front of the fuel tank while others place it toward the rear. Water is heavier than gasoline/ethanol, and it may not have reached a forward-located pickup tube.

I don't know whether ethanol percentage of "E10" is by weight (although it probably is, and will shift the numbers around a bit) or as volume. Discounting water content, and figuring it as % volume, 22.752 gallons of E10 gasoline should be 20.48 gallons of gasoline and 2.28 gallons of ethanol.

As @Borek says, water doesn't mix with gasoline (or hydrocarbons in general), but alcohol mixes with both. A portion of the ~ 2 gallons of "water" pulled from your gas tank was ethanol, and the remainder of the ethanol remained mixed in the gasoline. 73% ethanol in the 2 gallons separated out of the fuel tank is about 1.5 gallons of pure ethanol and 0.5 gallons of water.

Aside: The ability for alcohols to go into solution with both hydrocarbon fuels and water is what made 'dry gas' useful in removing small amounts of water from gasoline in the days before ethanol blended fuels became the norm. 'Dry gas' was originally a trade name for anhydrous methanol (and is still available as Heet in the red bottle) although anhydrous isopropyl alcohol (Heet in the yellow container) is superior in it's ability to remove water. The ability for ethanol to soak up moisture is somewhat between methanol and isopropyl alcohol and (so long as water content doesn't get way out of hand, as in your case) ethanol blended fuels serve as their own 'dry gas'.
 
  • #8
NCBryan
8
0
What make/model/year is the vehicle? Some manufacturers locate the pick-up tube towards the front of the fuel tank while others place it toward the rear. Water is heavier than gasoline/ethanol, and it may not have reached a forward-located pickup tube.

I don't know whether ethanol percentage of "E10" is by weight (although it probably is, and will shift the numbers around a bit) or as volume. Discounting water content, and figuring it as % volume, 22.752 gallons of E10 gasoline should be 20.48 gallons of gasoline and 2.28 gallons of ethanol.

As @Borek says, water doesn't mix with gasoline (or hydrocarbons in general), but alcohol mixes with both. A portion of the ~ 2 gallons of "water" pulled from your gas tank was ethanol, and the remainder of the ethanol remained mixed in the gasoline. 73% ethanol in the 2 gallons separated out of the fuel tank is about 1.5 gallons of pure ethanol and 0.5 gallons of water.

Aside: The ability for alcohols to go into solution with both hydrocarbon fuels and water is what made 'dry gas' useful in removing small amounts of water from gasoline in the days before ethanol blended fuels became the norm. 'Dry gas' was originally a trade name for anhydrous methanol (and is still available as Heet in the red bottle) although anhydrous isopropyl alcohol (Heet in the yellow container) is superior in it's ability to remove water. The ability for ethanol to soak up moisture is somewhat between methanol and isopropyl alcohol and (so long as water content doesn't get way out of hand, as in your case) ethanol blended fuels serve as their own 'dry gas'.

Yes, E10 is derived by weight.

Ok i think we are on the right track, more in layman's terms and should suffice. So basically the gas had .5 gallons of water in it and the ethanol being designed to dry the gas was attracted to the water and thus their should be no ethanol left in the gas? (+-)

So, how can I test the gas to determine the amount of ethanol present?

1978 Chevy K5 Balzer 4WD 305
 
  • #9
Borek
Mentor
29,172
3,847
I understand that. I have gas with 10% ethanol, water is added to the gas, water then (In some way??) contains 73% ethanol, how do I explain how the gas that only has 10% ethanol can cause the water to contain 7 times more ethanol. Saying ethanol dissolves in both gas and water in no way explains anything that the judge would not, most likely, already know.

In my mind I understand how it happens I just do not know the terminology to explain it.

Have you checked how is the partition coefficient defined? It tells you what is the ratio of concentrations. Basically it is about solving set of two equations - one is ratio of concentrations, second is mass balance - total amount of ethanol doesn't change, how much was present in the gas initially, that much is present in both water and gas afterwards. Yes, it means final concentration in one of the phases can be much higher than it was in the other phase, if the partition coefficient is high enough and there is lot less of one phase than the other.
 
  • #10
Asymptotic
782
528
ethanol being designed to dry the gas was attracted to the water and thus their should be no ethanol left in the gas?
There shouldn't be much water left in the gasoline, but there will be ethanol. That ethanol and water mix together is a by-product; by design, ethanol is there reduce fossil fuel usage, and to boost octane (rather than using MTBE or tetraethyl lead for this purpose).

I don't know how a lab would test for the amount of ethanol in gasoline.

Here is a drawing of a typical Chevy Blazer fuel tank arrangement. I can't say one way or the other looking at it whether the fuel pickup would tend to be in the water-rich area of the tank volume. http://www.lmctruck.com/features/cc/CC3CB.htm
 
  • #11
NCBryan
8
0
Have you checked how is the partition coefficient defined? It tells you what is the ratio of concentrations. Basically it is about solving set of two equations - one is ratio of concentrations, second is mass balance - total amount of ethanol doesn't change, how much was present in the gas initially, that much is present in both water and gas afterwards. Yes, it means final concentration in one of the phases can be much higher than it was in the other phase, if the partition coefficient is high enough and there is lot less of one phase than the other.

Let me say one thing, I am dyslexic so it is difficult for me to perceive certain things. I am good with math (not so much with word problems) but sometimes I can't tell the chicken from the egg. I appreciate you sharing this with me, I love learning, but I am one of god's curl jokes, a dyslexic INTJ. It will take me a while to get my head wrapped around it. Thank you for your patients.
 
  • #12
NCBryan
8
0
OK, I found this so I get it now. Thanks for guiding me to this.
I am still open to any other suggestions.

Thanks
 
  • #13
ChemAir
Gold Member
172
178
Without analyses of your tank prior, their tank, and your tank after, accurate discussion of three component miscibility in this case is probably a non-starter, and probably confuses the water decanting issue.

Some more mechanical thoughts why the car could initially run after filling, and not later, that might be easier to explain to the store owner and a judge:

1) Agitation, vibration, etc, during filling could prevent a large pool from coalescing or reaching the fuel pickup in the tank, at least initially. When left still for a while, the water will settle to the bottom of the vehicles tank, and will prevent the engine from running if the level reaches the fuel pickup (pump suction).
2) Another possibility is that the car was sitting at a different attitude when at the pump, making the low point in the tank somewhere other than the fuel pump pickup, only for it to be in a different orientation at a later time that submerges the pickup.

These speculations don't address unique issues that your car, its tank, fuel system, and induction system might bring that are different from the norm. Locating the fuel pickup location and return would be good to help determine which of the above may have contributed, though.

If you have full insurance coverage on the vehicle, it may be time to contact the insurance company to make a claim. They (the insurance company) may be better suited to argue this case.
 
Last edited:
  • #14
NCBryan
8
0
Without analyses of your tank prior, their tank, and your tank after, accurate discussion of three component miscibility in this case is probably a non-starter, and probably confuses the water decanting issue.

Some more mechanical thoughts why the car could initially run after filling, and not later, that might be easier to explain to the store owner and a judge:

1) Agitation, vibration, etc, during filling could prevent a large pool from coalescing or reaching the fuel pickup in the tank, at least initially. When left still for a while, the water will settle to the bottom of the vehicles tank, and will prevent the engine from running if the level reaches the fuel pickup (pump suction).
2) Another possibility is that the car was sitting at a different attitude when at the pump, making the low point in the tank somewhere other than the fuel pump pickup, only for it to be in a different orientation at a later time that submerges the pickup.

These speculations, don't address unique issues that your car, its tank, fuel system, and induction system might bring that are different from the norm. Locating the fuel pickup location and return would be good to help determine which of the above may have contributed, though.

If you have full insurance coverage on the vehicle, it may be time to contact the insurance company to make a claim. They (the insurance company) may be better suited to argue this case.

Thank you for your input. It could very well be 1 and 2.

I have been doing a lot of experiments since Borek turned me on to the partition coefficient thingy. Thank you again Borek.
I have determined/observed:
1. The amount of water is only .5+- gallons
2. Additionally there is 1.5+- gallons of ethanol.
3. it takes more that a couple of minuets for the 70% alcohol to precipitate out of the gasoline.
4. It is a 15 minute ride to the destination.
5. The 70% mix is inflammable.
6 It is a very curvy road to the destination.
7. It does not take a lot of agitation to combine the ethanol with the gasoline.

If i have overlooked anything please chime in.
Thanks.
 
  • #15
Efferneti
3
1
A few thoughts:

  • ethanol naturally forms an Azeotrope with water at 96% ethanol.
  • The petrol is likely to reduce the azeotropic level of water
  • How does the petrol get mixed with the EtOH? Is it done in situ or does the gas station get it supplied as a mixture?
  • How is it stored if it comes as a mixture?
  • The petrol would likely rise to the top over time if it is left to stand for a long while, liberating the EtOH and water
  • The EtOH will still be partially soluble in the ethanol, meaning that all of its azeotropic water may settle out leaving most of the EtOH in the water and some (dryer) EtOH in the petrol
  • If the above is true then you could have just got the dregs at the bottom of the gas stations store and filled ur tank up with that.
  • >>>>U may need to sue the gas stations supplier
 
  • #16
sysprog
2,613
1,783
Thank you for your input. It could very well be 1 and 2.

I have been doing a lot of experiments since Borek turned me on to the partition coefficient thingy. Thank you again Borek.
I have determined/observed:
1. The amount of water is only .5+- gallons
2. Additionally there is 1.5+- gallons of ethanol.
3. it takes more that a couple of minuets for the 70% alcohol to precipitate out of the gasoline.
4. It is a 15 minute ride to the destination.
5. The 70% mix is inflammable.
6 It is a very curvy road to the destination.
7. It does not take a lot of agitation to combine the ethanol with the gasoline.

If i have overlooked anything please chime in.
Thanks.
You might ask the judge to consider the water as mainly being added to only the 10% ethanol component of the fuel. It's common knowledge that water mixes easily with alcohol, and that it doesn't mix with petroleum products. For example: 80 proof vodka is about 60% water, and it stays mixed, whereas oil and water don't mix, or at least don't stay mixed -- that's why you shake the bottle of Italian dressing.

E10 can absorb about 20ml of water per gallon before phase separation starts to pull water-diluted ethanol out of the gasoline.

Here's an EPA reference on the matter: https://www.epa.gov/sites/production/files/2015-09/documents/waterphs.pdf
 
Last edited:
  • #17
I_think_4_myself
1
0
Do not know if this was contributed:

There may have been a little water in your tank before you gassed-op.
Not enough to be sucked into the pick up tube.
As said above,
The E10 you purchased had about 2.5 gals of ETOH in it, and perhaps a little water too, up to maybe a quart, but not enough to separate out. When it splashed into your mostly empty tank, between any water in the bottom of your tank + whatever was in the gas was a sufficient amount of water to grab the ETOH. The mixture in your tank reached an equilibrium at 2+ gallons of 73% ETOH and water, and likely 25gls of 4% ETOH and gasoline. Unfortunately that 2+ gals was enough that the fuel pick-up line was now sucking up a 73% ETOH and water mix, slightly weaker than 151 Rum, me hearty...With the fuel air mix setting on your truck, there was an insufficient % of ETOH vapors to combust. Your truck would not start.
Also consider:
The flashpoint of 70% ETOH is 62F. Depending on where you live, the temperature of the fuel in the underground tank may have been as low as 52F. Also depending on where you live, the outside temperature in April may have been less than 62F. After your truck sat, the temperature of the ETOH may have been below its flashpoint.
A definite NO GO!
 

Suggested for: How can 10% ethonal gas produce 73% alcohol? (with water)

Replies
21
Views
557
Replies
22
Views
1K
  • Last Post
Replies
2
Views
391
Replies
11
Views
653
Replies
3
Views
411
  • Last Post
Replies
24
Views
2K
Replies
3
Views
431
Top