Chemical Engineer types - Ethanol? and motorheads

[ascast]

I have a couple questions on the ethanol issue. I would like to get some real scientific answers. I'm sure somebody out there knows exactly what I am talking about.
as background info; I have used 89oct 10% E for everything on the farm. The ONLY time I have had trouble that I know for sure was Ethanol was in as tractor that would not run after a rain. I found a 5 inch crack in the top of the gas tank from a "bubba" brazing job. Prior to this find, I would have to drain out a bunch of fuel before it would clear up and run the engine. The contaminated fuel would burn if poured on a stick and a match was used, but not under compression. No visible line between gas and water was noticed. No line appeared when lots more water was added to sample. No apparent saturation point. Yet it would still burn.
So...

PART #1
I would like to have a Chemical Engineer type or similar do a molar balance on the Ethanol-gas issue. It has been years for me and I am too lazy to figure it out.

What I am looking for is just how much water will be absorbed by a gallon of fuel.

Lets say 1 U.S. gallon, 89 octane, 10% ethanol. Assume other additives are trace and not significant. (unless you know differently)
You may use metric or SI for calculations, but express result in "bubba" units, like pints or tablespoons or provide conversion factors. Or a % increase in gross volume. remember, nobody can visualize 17.3 milliliters, or 637ml either
you need not show your work, but if you can, great

PART #2
For the motor heads - I have been told that modern full on computer ignition systems in cars will compensate for Ethanol / water contamination fuels. I run nothing newer than 1995 so I have no real experience.
I understand that real gasoline needs about 1:13 oxygen to be explosive at STP. It is different in a pressurized vessel, like a piston/cylinder.

So..
Is this true
What is max water content ( saturation) for, say 86 Oct 10% E to be a viable fuel in a standard car? Standard use, start up and go, no coughing or bogging down under load _ BUT
NOT hot rodding.

I would like to get some general discussion on this from people schooled or job experienced to know, several levels above bubba.




ps yes, most people think I am a nerd/jerk etc.... sue me

[SciFiJim]

Interesting things I have wondered myself. I will keep an eye on this thread. I hope someone can supply the answers.

[ironmonger]

This is completely anecdotal, but I remember reading on a motorcycle forum that ethanol could be removed by 'overloading' the gasahol by adding water. Shake it up and let it stand and the water ethanol/gasoline would separate. The down side was that the remaining gas might not have as high an octane as the original mixture as the alcohol is used to raise the octane in addition to screwing up the fuel. I have not tried this, just lazy, I guess.

I have a few 2 stroke engines that I use ethanol free fuel in. I purchase ethanol free premium from outside of my county and add Stabil, Isoheet and Lucas top end lube in addition to the 2 stroke oil. This fuel, minus the 2 stroke oil, is used in my 4 stroke snowblower as well... ugly but necessary here in the dark months... which I park in the spring with a full tank of fuel and restart in the fall with a pull or two on the rope.

paul

[NavyVet1959]

It's been said, "Using ethanol in gasoline is a waste of perfectly good corn squeezings". I tend to agree with this. My truck gets considerably worse gas mileage with an ethanol blend. You would think that with 10% ethanol, at worse you might get 10% worse fuel economy, but I get about 20% worse.

Also, my carbureted motorcycles are more likely to get gummed up if I don't constantly ride them with ethanol contaminated fuel. My fuel injected motorcycle does not have that problem.

[JonB_in_Glencoe]

Check into the actual recommended shelf life of Gas.
I haven't checked into this for a few years...maybe even a decade, But IIRC when I did:
Non-oxy fuel was 30 days
Gas with 10% ethan was 15 days.

An old timey farm tractor, with the fuel tank on top of the engine, if sitting outside, will see greater temp changes, humidity changes, speeding up the degradation. But you probably already knew that.

signed, Bubba Jon

[pmer]

I seem to remember a car guy on the radio saying 10% ethanol blended fuels can and do have water but you don't need to add products like HEET to displace the water because the ethanol is doing that already.

As far as air to fuel ratio, it needs less air for a proper burn. In other words you can go richer which is why economy goes down. I suppose newer cars sense a change in exhaust temperature.

A little thread drift here but E85 in a race application is pretty fun if you set up your engine to run on it. Economy goes out the window but its cheaper than race gas.

[ironmonger]

I seem to remember a car guy on the radio saying 10% ethanol blended fuels can and do have water but you don't need to add products like HEET to displace the water because the ethanol is doing that already.

<<polite snip>>

The Iso-Heet is isopropyl alcohol. It can hold a much higher quantity of water in solution than the ethanol. The water/isopropyl mixture is more miscible with the gasoline. The amount water that ethanol can hold in suspension is lower than what the isopropyl can hold. Not saying it's a good thing, just making the best of a bad situation.

My auto parts store had a display that consisted of two test tubes, one had gasoline and ordinary heet and water, the other had all the same stuff except iso heet was substituted for the standard heet, which is methanol I believe. When you shook the display the methanol would break up the water that was laying on the bottom of the tube in to a cloud of tiny 'bubbles' which then promptly separated and fell to the bottom of the test tube. Very graphic and they’ve had me ever since.

paul

[popper]

Non-oxy fuel was 30 days Gas with 10% ethan was 15 days.

And all the additives are placed in the delivery tankers for local GS. H2O injection was used in prop WWII aircraft for added power at takeoff, old de-carboning trick was to trickle H2O into the carb - much higher combustion pressure with some cooling effect. Ethanol has much lower energy content than methanol.

[bangerjim]

It's been said, "Using ethanol in gasoline is a waste of perfectly good corn squeezings". I tend to agree with this. My truck gets considerably worse gas mileage with an ethanol blend. You would think that with 10% ethanol, at worse you might get 10% worse fuel economy, but I get about 20% worse.

Also, my carbureted motorcycles are more likely to get gummed up if I don't constantly ride them with ethanol contaminated fuel. My fuel injected motorcycle does not have that problem.

My Lexus hybrid vehicles give instant, 10 minute, and total gas mileage reports on the LCD screen of the nav system. I can DEFINITELY see a decrease in MPG on the winter to summer blends we use here in PHX.

Other areas of the state do not use MTBE or ethanol and the mileage is better!

banger

[xman777]

So this depends on if you want real world knowledge or pure chemistry/physics knowledge.
My credentials: MSCE Penn State. Current job: Lead Field Process Engineer semiconductor industry. 10 years in gas industry. Mostly compressed.
First some observations:
~I'll guess that your under compression scenario was that you were compressing the contents in the bottom of that tank and that just so happens to be the phase separation layer. This layer is almost entirely ethanol and water. Not flammable at all.
~Additionally for the pour test, you are likely combining both layers in a concentrated stream thus some flammability should have been noticed.
With E10 fuel at 15°C (Call it 60°F), this saturation point is at approximately 0.5% water to the volume of fuel. Once the blended fuel reaches this saturation level, the ethanol-water mixture separates from the fuel and falls to the bottom, since its density is now higher than the fuel with which it is mixed. In this layer, where when saturated would separate from the rest of the gasohol, there will typically be 3-4 parts of ethanol for each part of water. This would be called Phase Separation. You can google that for some more fun with numbers if that excites you.
Is that all you wanted to know chemically?

With regard to the gearhead in me:
My credentials: HOBBYIST. Formerly ASE Certified in my younger days, before I got tired of being a grease monkey.

If you can fiddle with the compression ratio, it really will be hard to put a bad fuel in it. Your injectors/nozzles and compression help the most with the explosive nature of the gasoline, not so much its octane rating. That said of course, there will be a point where wet gas will simply not fire, but you can tweak the curves with a stand alone system like a F.A.S.T. You'll need a high end ignition though. Something like an MSD. I'd say if you have access to a dynamometer and a nifty auto programmer like myself, well you could just about run mayonnaise in your car. I run a farm tractor off of recycled motor oil. It fogs the mosquitoes as a bonus. The basics of gasoline engines are suck, squeeze, bang and blow. Mess with any combination of that and get it right, you're well on your way for whatever this project consists of. No matter what you do, you cannot run phase separated ethanol in the tank. Good luck!

[dkf]

I seem to remember a car guy on the radio saying 10% ethanol blended fuels can and do have water but you don't need to add products like HEET to displace the water because the ethanol is doing that already.

As far as air to fuel ratio, it needs less air for a proper burn. In other words you can go richer which is why economy goes down. I suppose newer cars sense a change in exhaust temperature.

Ethanol doesn't replace a product like HEET. Yes ethanol will mix with water. The problem is the ethanol and water mix does not want to mix with the gas. Thus when the vehicle is parked the water/ethanol mix will settle to the bottom of the tank. The fuel pick up is at the bottom of the tank as well. Products like HEET make the water mix with the gas so it can be ran through the system and burned.

Stoich for E10 is around 14.2:1 and pure gas is 14.7:1 so yes you need more fuel with E10. Some vehicles have sensors in the fuel system can that can detect the octane rating and adjust accordingly but most of them are newer flex fuel vehicles. A lot of older vehicles still are set up to run a 14.7:1 A/F ratio which can be problematic.

I prefer fuel without ethanol. If the EPA gets their way and mandates over 10% ethanol there are going to be a lot more problems than we have even now with E10.

[perotter]

Ethanol doesn't replace a product like HEET. Yes ethanol will mix with water. The problem is the ethanol and water mix does not want to mix with the gas. Thus when the vehicle is parked the water/ethanol mix will settle to the bottom of the tank. The fuel pick up is at the bottom of the tank as well. Products like HEET make the water mix with the gas so it can be ran through the system and burned.
......

For years gasoline with ethanol in it has been all that is sold here in MN. It's hard to even find someone under 40 years old who has even heard of a gas line freezing or know what HEET is or why one would use it. It's even getting hard to find HEET to buy.

In the pre-ethanol days it was normal for most people to put a can of HEET in the tank every time gasoline was bought from December thru March.

[Skunk1]

I can't burn ethnol in my car or truck during the summer. Causes them to vapor lock. Jeep runs good on it, gas mileage isn't that great but I don't use it in any of my small engines. My 2 old fords get straight gas also. We have a couple ethnol plants near me and I've heard they give tours but don't really have any interest.

[MtGun44]

First issues is that ethanol has roughly half the energy per gallon as gasoline, so with 10%
ethanol, you will use somewhere around 5% more fuel per mile. Next issue is corrosion -
somewhere beyond 10% (memory says something like above 16% or so, may not be right)
you get some nasty corrosion issues.

One big issue can be excess water causing the ethanol water mix to drop out of suspension in the
gasoline, leaving a layer of ethanol water on the bottom, messing up your system. I think the max
percentage of water in 10% gasohol is only about half of one percent before it is a problem.

Bill

[.45Cole]

1. You seem to understand mol ratios, in chem e there are usually mass ratios. You are looking for a tertiary phase diagram of the octane(or a BTEX)-water-ethanol system. In a limited search I found physical data, but not an actual diagram (you would most likely have to pay for one). If you played nice and called a refiner's process engineer, you might get one. Assume octane or hexane to be your hydrocarbon. Page 1088
I know that the Reid vapor pressure is guaranteed for something like 60 days when I saw fuel reports from working at a grocery store. That is its volatility (kinda like it's flammability) and the lower the RVP, the higher the octane rating I assume.

Ethanol is totally soluble in water and water is minimally soluble in gas. You can extract the ethanol out of the gas using water, then allowing the gas-water mixture to phase separate, then skim off the ethanol/water phase. A couple of times of this should do the trick.

2. Some supercharged cars inject water/methanol solution into the intake to cool the charge air rather than use an intercooler. My cousin dilutes HEET with water to inject into his mustang. The water of course doesn't combust, but will go into the vapor phase, absorbing energy in the process; with a supercharger he really doesn't see it (and you lose so much to heat and sound anyhow) As long as the water isn't allowed prolonged contact with the metals of the car, it shouldn't rust as the hydrocarbons are probably the wetting fluid.

Bonus. Jets will inject water into the engine because the water vapor expelled has more mass than the resultant combustion gasses. The jet is propelled by the simple physics m1v1=m2v2. More mass (combustionn gasses) moving at a higher velocity pushes the other mass (jet) to higher velocity as the jet's mass doesn't change (relatively). Once again, the energy loss to the latent heat of water (phase change) is minimal to the energy generated by combustion.

[.45Cole]

"Or a % increase in gross volume" that's a nasty calculation, unless you have some sophisticated measuring devices. It takes a GC or some other form of chromatography to pull constituents of a phase; I think you will have to go the phase diagram way or a simulation software package, but I have neither.

[AllanD]

One comment I've made about Ethanol in gasoline is a simple one that nobody answers...

Ethanol costs $5-$7/gallon to produce under ideal circumstances, so ignoring government subsidies on ethanol
and government mandates to add it to our gasoline, at what point does adding $5-$7 Ethanol to our gasoline
accomplish anything other than create an Ethanol fuel industry, that could not exist economically without the
subsides and mandates?

[GhostHawk]

AllanD you could if you wished even go so far to say that to grow corn, haul it, turn it into Ethanol burns more oil than the Ethanol replaces. Gallon for gallon you are in the hole, big time. Not that I'm against making alcohol out of corn, by all means, Pappy's corn squeezins is good stuff. But don't waste it putting it in cars.

Get the government out of the subsidy business, concentrating on where they can cut waste and we might have a chance at a balanced budget. And while you are at it, bring the boys home, put them to work on our borders, and inspecting anything and everything that enters our ports. And quite for pete's sake giving money and aid to country's that hate our guts so we can have an airbase on their soil.

Plain fact is the USA has been spending more than it brings in since WWII with a few minor hiccups.
You can't spend yourself out of debt. You can only do that by living below what you take in, and working hard, being frugal.
But that is NOT what government wants. It wants control, you get that with money.

[perotter]

One comment I've made about Ethanol in gasoline is a simple one that nobody answers...

Ethanol costs $5-$7/gallon to produce under ideal circumstances, so ignoring government subsidies on ethanol
and government mandates to add it to our gasoline, at what point does adding $5-$7 Ethanol to our gasoline
accomplish anything other than create an Ethanol fuel industry, that could not exist economically without the
subsides and mandates?

Do you have the break down on that $5-$7?

Do you have the details of the subsides? The Federal tax credit expired in 2012. A tax credit isn't a subsidy, unless one thinks that everything belongs to the government and what they don't keep is a subsidy.

[perotter]

AllanD you could if you wished even go so far to say that to grow corn, haul it, turn it into Ethanol burns more oil than the Ethanol replaces. Gallon for gallon you are in the hole, big time. Not that I'm against making alcohol out of corn, by all means, Pappy's corn squeezins is good stuff. But don't waste it putting it in cars.

Get the government out of the subsidy business, concentrating on where they can cut waste and we might have a chance at a balanced budget. And while you are at it, bring the boys home, put them to work on our borders, and inspecting anything and everything that enters our ports. And quite for pete's sake giving money and aid to country's that hate our guts so we can have an airbase on their soil.

Plain fact is the USA has been spending more than it brings in since WWII with a few minor hiccups.
You can't spend yourself out of debt. You can only do that by living below what you take in, and working hard, being frugal.
But that is NOT what government wants. It wants control, you get that with money.

Do you have any study that shows that it takes more oil to make ethanol from corn than fuel that is produced?

You skip the study that the bug doctor did, as it says that it takes 1000 gallon of fossil fuel to grow an acre of corn. If that was true, there would be no fossil fuel of much of anything else. Also, keep in mind that it takes more than a gallon of oil to produce a gallon of gasoline.