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  #1   IP: 66.173.202.15
Old 12-19-2006, 10:48 PM
Bob N Bob N is offline
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Another ethanol question

Does anyone have any data about the effect of temperature on ethanol separation from gasoline? I'm wondering if cold temperatures--like during winter storage-- might slow the process. (Wishful thinking, I know.)
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  #2   IP: 38.118.52.41
Old 12-20-2006, 02:50 PM
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Here's a link to some interesting reading on this subject. I found this on an EPA website.

Bill

Last edited by Administrator; 12-20-2006 at 05:44 PM.
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  #3   IP: 66.173.202.15
Old 12-21-2006, 11:16 PM
Bob N Bob N is offline
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The article attached to this link was very useful.
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  #4   IP: 38.118.52.41
Old 01-03-2007, 01:56 PM
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We have been reading and studying this recent EPA memo on water phase separation properties of 10% Ethanol fuel with great interest. This study is one of the first technical reports we’ve seen which contains sufficient quantitative information to actually give us an insight into how much water it would take to saturate Ethanol fuel and what it would look like if you added water beyond that point.

It was surprising to us to learn that a gallon of 10% Ethanol fuel would hold 3.8 teaspoons of water in solution, or 0.95 teaspoons per quart. We decided therefore to conduct a small (very unscientific) experiment to see what this amount of water looked like, and perhaps more importantly, whether or not this amount of water would really burn with no abnormal symptoms in an engine.

Test procedure:

We cleaned and dried 3 spaghetti sauce jars and put a quart of 10% Ethanol fuel in each jar. Being unable to measure hundredths of a teaspoon, we added one whole teaspoon of water (0.05 teaspoons over the theoretical saturation point) to the first jar, two teaspoons of water into the second jar, and retained the third jar as a reference point with unaltered fuel. For our test engine, just in case the operational results might be more damaging than expected, we used our faithful 6 HP John Deere single cylinder naturally aspirated family push lawn mower to test the saturated fuel.

Observations:

The water in both the first and second jars fell immediately to the bottom of the jars and lay there perfectly separated from the fuel. Even when we shook the jars to momentarily disperse the water throughout the fuel, it continued to settle out rather quickly as soon as we stopped agitating.

After approximately 30 minutes, however, as we sequentially continued to agitate the fuel and allow it to settle, some of the water seemed to linger behind in suspension for 10 to 20 minutes, creating a grey opaqueness in both jars one and two. See first attached photo of jar one and the reference jar.

NOTE: The black ring around above the opaque fuel in jar two is a magic marker line on the outside of the jar to indicate one quart.

During the time the fuel was clear there was a slight trace of water in the bottom of the jar one, but during the time the fuel appeared opaque (after agitation) there was no free water in evidence on the bottom of the jar. We assume this trace of water in the bottom of the jar between agitations to be the 0.05 teaspoons of water that we were attempting to “oversaturate” the fuel above the theoretical limit.

Not surprisingly, the same tendency to create a gray opaqueness appeared in jar two. However, the amount of water settling to the bottom of jar two was greater, apparently reflecting the second teaspoon of water (the amount we were attempting to oversaturate the second jar). See second attached photo.

Operational test:

For testing the saturated fuel, we sequentially added approximately one cup of the 100% water-saturated fuel from jar number one and two and operated the mower until it ran out of fuel in each case. The only apparent difference in the samples of fuel being added to the mower was that in the case of jar number two, the fuel was decanted from above a teaspoon of free water lying in the bottom of the jar.

In a nutshell, we observed no difference when operating on the saturated fuel from either jar, except for one small subtle symptom; when the engine was fully warmed up, it exhibited a mild tendency to backfire one time on most start-ups, but never to the degree of being hard to start.

NOTE: In our test, we actually transferred the test fuel while it was still opaque just after agitation to be sure that we had a worst-case situation from jars one and two. In other words, we believe we were using fuel in a slightly “supersaturated” state from both jars.


Conclusions:

1) The test tends to confirm 10% Ethanol fuel’s ability to absorb 3.8 teaspoons of water per gallon (a surprising 0.75 cups of water per 10 gallons). When more water is added, it simply settles to the bottom of the container/tank.

2) To this point, water-saturated Ethanol fuel has not adversely affected our test engine. We believe the slight tendency to backfire during starting was due to the fact that the saturated fuel resulted in a very slight leaning of the fuel/air mixture.

NOTE: We’ll continue to use saturated Ethanol fuel in our mower as long as the weather permits and continue in the spring. We’ll report results if they prove to be remarkable in any way.

3) Water which settles to the bottom of the tank (water in excess to 0.75 cups per 10 gallons of fuel) will of course present the same hazards to reliable operation with Ethanol fuel as it did in MTBE fuel. To this point, however, the free water in the bottom of the sample containers exhibit no threatening characteristics which would create additional problems to those normally associated with free water in any fuel (being sucked up into the feed tube during heavy sea conditions, etc.).

4) Based on another section of the EPA report, keeping fuel tanks full will minimize water absorption from moisture in the air above the fuel. However, whether a tank is kept empty or full, unless free water is introduced to a tank during refueling or draining into the tank from rain or melting snow, it is practically impossible to saturate Ethanol fuel from moisture from air alone.
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Last edited by Administrator; 01-03-2007 at 02:57 PM.
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Old 01-04-2007, 12:10 PM
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Ethanol in Fuel

As a chemist and an atomic 4 owner, I wanted to pass along some information that may be helpful. The three major simple alcohols that we deal with as consumers are, methyl alcohol, ethyl alcohol and isopropyl alcohol. Methyl alcohol has and is still used as "dry gas". Its a water scavenger which means it combines with water in our fuel systems, autos having been the main use for decades. While effective methyl alcohol is a low octane dry gas and it can cause your car to run a little rough while its being burned and the water "attached" is being vaporized. Ethyl alcohol has a higher octane rating and picks up water in the same fashion. A dry gas that is ethyl alcohol makes the burning of the alcohol/water solution smoother.

I have found that isopropyl alcohol, which can be obtained as a dry gas, such as "heet", has a much higher octane than the methy or ethyl alcohol. It can actually help boost the octane of your gasoline when it is added to it and also get rid of water. You have to look at dry gases carefully, many are methyl alcohol which I wouldnt use in my lawn mower. Others are ethyl alcohol and isopropyl alcohol, you have to pay more for the isopropyl alcohol but its worth the extra 75 cents a bottle and if you know that you have some water in your tank or even suspect water in small amounts it will be beneficial for you to add the isopropyl. You have to read the small print on the back of the bottles to make sure what youre getting though because all of these dry gases will advertise on the bottle that it will make your engine run smoother.
I add a bottle 12-16 ounces of the isopropyl alcohol to every tank of gas so I pick up 4-6 bottles when Im at the auto store.
One major thing to NOT do is to buy rubbing alcohol because it already has tons of water in it. If you were able to get isopropyl alcohol in larger quanities from a chemical company to help keep the cost down, purchase ONLY anhydrous alcohol, which means there is no water in it!
I hope this info can be helpful to you.
Sincerely
Bob
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  #6   IP: 68.43.29.20
Old 01-06-2007, 05:11 PM
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Ethanol and water

Hello, I just wanted to say that this was a very informative article and I will be sure to follow the advise given. We currently do not have ethanol gas here in Michigan yet and least on the water. I have been living with the Venerable Atomic Four for at least 28 years. Two boats. A 1970 Bristol 29 and now my 1977 C&C 36.
Thanks for the information.
Rick
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  #7   IP: 38.118.52.41
Old 01-06-2007, 11:03 PM
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Bob,

Thank you so much for sharing your very credible information regarding the different alcohol products. Do you have any sense of how much isopropyl alcohol one could use with 10% Ethanol fuel in an attempt to remove free water from the bottom of a tank? In other words, if one can of "heet" per tank full of fuel is good, would two cans be better?

Don
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  #8   IP: 38.118.52.41
Old 01-07-2007, 07:22 PM
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Don Moyer Don Moyer is offline
 
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Noel,

Your first question is easy to answer. According to a very authoritative report by a chemist (Bob) which appears on our Community Forum directly below the report we made on our test here at MMI, "Heet" is composed of isopropyl alcohol.

We had much the same question that you did regarding adding isopropyl alcohol (Heet). Notice in a follow-on question to Bob's report were asking him whether or not adding Heet to Ethanol fuel (or even two cans) will incrementally increase Ethanol fuel's ability to pick up more water.

Don
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