Chemical Engineers - I need your help

[meadowfield 2,808]

 

 

Boo, the other question I have is when the ethanol absorbs water, does it actually change into a different compound or does the ethanol just hold onto the water? I guess my question is like asking if a sponge is no longer a sponge just because it now has absorbed water.

 

 

 

 

 

[meadowfield 2,808]

 

 

This is what I fear most - oxide particles plugging the carb passages more so than hydrocarbon or alcohol residues Oxide particles cannot be spray cleaned away with a shot of carb cleaner and may account for many of the "non - repairable" carbs we toss away. .We may all need a lesson on popping off the welch plugs on carbs to mechanically clean out oxides from the passageways.

 

Boo, the other question I have is when the ethanol absorbs water, does it actually change into a different compound or does the ethanol just hold onto the water? I guess my question is like asking if a sponge is no longer a sponge just because it now has absorbed water.

 

 

When ethanol mixes with water it is diluted ethanol - by nature a compound...  So yes it is still a sponge  separation can only be achieved by squeezing  or distillation

[wheeledhorseman 579]

Living in the UK I sometimes forget that we share a 'common language' that's different and I don't always manage to allow for this. It was called ethyl alcohol when I did chemistry at school but later when teaching chemistry we had adopted 'ethanol' as part of the IUPAC standardisation.

 

Ethanol = ethyl alcohol = C₂H₅OH = the stuff they're adding to gas.

 

The fact that it is miscible (mixes) with water is a good lhing if you like beer which wouldn't be the same otherwise.

Water can be separated from ethanol by distillation, again a good thing if you like your spirits otherwise these would not be possible.

The last 1 - 1.5% of water cannot be removed from ethanol by distillation or other means so in a way there is no such thing as 'pure' ethanol. Absolute (200 proof) alcohol always contains that last little bit of water that can't be removed even if it is sometimes called ''dehydrated'.

 

When water mixes with alcohol it does not change the chemical formula of the ethanol which remains C₂H₅OH, they are simply mixed together. Ethanol will mix with water in any ratio hence the range of week beer - strong spirit - absolute (sort of pure) alcohol that's used in the medical world and certainly not suitable for drinking! 

 

Adding it to gas certainly changes the properties of it as a fuel, I say this for a number of reasons that are confirmed to my mind by the fact that here in the UK whereas regular unleaded does not have to meet a specific standard, super unleaded (higher octane) still does and the oil companies seem to have delayed adding ethanol, presumably because they cannot make it meet that standard.

 

Kohler would, I guess, have extensively tested fuels available at the time round the world before stating that up to 10% ethanol was ok. They do say that no other gas / alcohol blends are approved which I take to mean ethanol over 10% or the use of methanol (methyl alcohol) in any quantity. It is the prospect of 15% ethanol in gas that is perhaps most worrying and the point at which many of the scare stories start to become a reality for older engines.

 

Picking up on Mark's point about fuel pumps - my 316 has been problematic to start since I got it a year or so ago if left for a few days even with the tank valve closed to prevent drain back. Easy to have blamed that on the fuel but a new pump has cured it completely and the Onan is now 'on the button' as we say here. The pump could obviously still pump fuel but I guess the valves had become leaky and maybe the alcohol content increased this effect but it was the original pump that had done 1700+ hours.

 

Don't get me wrong, I hate the new fuel, not least for the way it is far more aggressive in attacking some types of enamel paint if spilled on it and the fact that we are told that it is a 'greener' option when many eco organizations disagree with this.

 

Andy

 

 

 

 

 

[Coadster32 793]

Really interesting thread. Wish I had something interesting to add to it...other than distilling ethanol happends at 152 degrees F. 

[papaglide 542]

I find this thread interesting as well. I hope that we can come to some sort of conclusion regarding this.

[dcrage 631]

I was going to chime in today, but Andy beat me to it on the 'mechanics' of ethanol mixing with gasoline; i.e. it is a true solution with NO chemical reaction occurring -- A small addition/correction which might be of interest to some of us

 

From Andy's last reply:

 

"Water can be separated from ethanol by distillation, again a good thing if you like your spirits otherwise these would not be possible.

The last 1 - 1.5% of water cannot be removed from ethanol by distillation or other means so in a way there is no such thing as 'pure' ethanol. Absolute (200 proof) alcohol always contains that last little bit of water that can't be removed even if it is sometimes called ''dehydrated'."

 

Not quite true -- There is high purity (>99.9%) ethanol out there (You would never want to drink any of this stuff!!!) -- One historical way to obtain this is to make use of an "azeotrope distallation" where another solvent is added (benzene or toluene are two examples) and the mixture of these two organic molecules (ethanol + benzene) can be distilled away from the water and then the ethanol can be seperated from the co-solvent by normal distallation -- There will be traces of the co-solvent (benzene; bad stuff to consume) left in the resultant mixture -- There are other techniques available (use of "molecular sieve' to absorb the water for example) -- All cost $$$$ and you would need to have a really good reason for needing to get rid of the 1-2% water

[tunahead72 2,581]

Really interesting thread. Wish I had something interesting to add to it...other than distilling ethanol happends at 152 degrees F. 

 

It figures that Steve would "like" this particular post.

 

Can't say that I blame him, I do too.

 

I don't understand most of what you guys are discussing here (barely passed high school chemistry and had no business taking it in college, but I did), but it IS interesting, can't wait for the actual experiments.

[AMC RULES 37,236]

I imagine Steve may be home conducting laboratory experiments...as we speak.       

Edited June 6, 2013 by amcrules00

[boovuc 1,090]

Well I have two of our crack team looking into it. (This may also be a polite way of these guys blowing me off but that remains to be seen).

SOI. Your question was answered earlier in the thread. The ethanol will just become more dilute with water. Since water and ethanol are completely miscible, you could have a 70/30 mix of ethanol/water or just the reverse.

Isopropanol, (Isopropyl alcohol), and water at 70/30% is commonly referred to as Rubbing Alcohol.

Getting rid of water is easy in a fuel system. Getting the corroded/oxidized residuals from the water is the problem. I have also seen what I called "gelled gas" where the gasoline has simply broken down. (Colored turned darker, micron sized gels are visible, viscosity has risen). 

This comes with age and will hose a carb quicker than water will. The combination of the two is worse yet!

A lot of fuel distributors test there own tanks for semi-accurate readings of the amount of ethanol they need to add by using a product called "Quick Check Solution kit" and similar fuel industry indicators.

I'll stay on them until I get an answer for discerning gasoline, alcohol and water if possible. (Quick check can't discern the alcohol and the water content if present).

[Keith 21]

I think that alcohol absorbs water is the major problem.  If you make a habit of running the fuel tank to near empty there will be less problems, then drain the tank before adding fresh fuel.  The humidity from the atmosphere condenses into the fuel, eventually the water separates and settles out.  Instead of just shutting off the ignition use a valve to allow the motor to consume the fuel in the lines and carb.  Alcohol is more corrosive on metals than gasoline, but I think the mix with water causes most problems.  The alcohol causes rubber to soften over time but new fuel lines are a minor repair.  The water in the fuel rusts a metal tank, the dirty tank sediment gets into the carb.  A plastic fuel tank compatible with ethanol improves the situation.  On the new motor I just got the manual says to not use a metal fuel tank, but the motor came with a metal fuel tank.

[Anglo Traction 761]

Great Thread you started here SOI!. I'm no Chemist or Geek, but loved Physics/Chem at school.

I found a link to the process you plan to adopt that may be of interest- http://www.google.com.mx/patents/US4962039

I understand the principle of identifying the presence of H20 in your Fuel samples, but my curious mind tells me that, if Ethanol contains an element(quantity) of water, would your 'Identifier Dye' that you use, actually colour the Ethanol?.

I can understand that if your testing pure petroleum, any water would separate at the bottom and the dye would find it/show up clearly. In an Ethanol/Petro mix, would it not be suspended, and subsequently tint the whole sample?.

[wh500special 2,352]

Chuck,

I'm late to the discussion and I see a lot of things have been covered, but I have a few comments.

Today's gasoline is good stuff. I've been living right i guess since I can't blame stale fuel for any problems I've had even though people around here insist that we have bad gas. Or, maybe they mean something else...

I'm a chemical engineer, but have been sort of out of my field for a few years. I also think I know everything about every single subject, so take anything I say with a pound of salt and a shot of ethanol (etoh).

I'd think that finding a alcohol only soluble dye will be difficult for the experiment you'd like to conduct. I'll look in some of my catalogs next week when i get back in the office.

In addition to having an affinity for water, etoh also dissolves extremely well in gasoline. The gas likes the other end of the etoh molecule that the water does. Since water and etoh like to stick together, I think you'd be fighting solubility of your dye in both phases of the mixture (ie some etoh will remain in the gasoline phase even after phase separation and will carry dye with it). If you do find a dye, I think you'll want to use the absolute minimum amount possible to decrease its tendency to color the gasoline phase of the liquid.

Huzzah for ethanol in gasoline! I believe it probably prevents more water issues than it causes in almost all instances (marine engines being the exception). The fact that it draws water out of the tank keeps it from accumulating in significant amounts. Etoh's affinity for water probably reveals existing equipment problems with water intrusion into the fuel system. With pure gas, these problems are disguised since the water usually sits at the bottom of the tank and doesn't get sucked into the fuel line and pumped upstream.

That said, phase separation is a real phenomenon but it shouldn't be a problem for fuel tanks or engines that don't get doused with water regularly. In a boat gas tank or underground tank water can get in through leakages of one sort or another. These aren't likely moisture accumulations from breathing by the vent system of the tank trapping airborne humidity since that trivial amount of water would be sucked up by the etoh and carried harmlessly through the fuel system and engine.

Older fuel storage tanks that never had alcohol enhanced fuels generally ought to have a puddle of water sitting in the bottom of them. When the fuel truck dumps a new load of alcohol laced gasoline that water is soluabilized to some degree and comes up the pipe with the gas. Along with it comes the water soluble crud and schmutz that had previously sat harmlessly in the bottom of the tank. This was a problem when gasohol was introduced in the 1970's and isa problem again now that all fuel sold must average some percentage of ethanol (this is thanks to the corn growers association by the way) as an octane improver.

There can be rubber issues that ethanol exacerbates. Usually, it affect sold seals and gaskets that were (postulating here)going to have problems in the near future anyway. Just be thankful we don't use methanol. It's even more aggressive on rubbers and plastics.

I don't use stabilizers as a matter of routine. The gas in my generator was installed when I moved into this house 3 years ago. I thought I stabilized it, but I notice my only bottle of stabil is unopened, so i might have never gotten around to it. It starts up first pull every month when I exercise the thing. 3 years does make me a bit nervouse though, soone of these days I will be draining it and putting it in the car. All of my questionable fuel goes in the car by the way. I figure dilution will take care of any problems.

The ethanol in fuel issue is something that almost believers on both sides at nearly religious levels. For the last 20 years I'vegenerally sought out the fuel that was doped with ethanol so you can imagine what side I'm on. For me, it's always been about keeping the water from accumulating in the tank. We know it's going to get in there,so etoh gives it a way to get out. On the east coast evidently theytraditionally spiked the fuel with mtbe, so now you're all paying the water price we did in the Midwest 30+ years ago.

The only better use for ethanol is for filling the cup of a certain guy from Elgin.

Best wishes,

Steve

I apologize for the typo's. The iPad won't let me use capital letters properly either...

[boovuc 1,090]

I agree with you Steve in that ethanol fuels take care of moisture issues. When one thought we had an issue with water in our gasoline, we added "dry gas" which was "ethanol". Methanol is more aggressive than ethanol on rubber components but any alcohol is more aggressive on rubber and synthetic rubbers than gasoline period. (Think about that when you realize what is at the end of all our carburetor's needle valves).

I know this is off-topic from SOI's hunt for phase indicators.

All in all, there are pros and cons to 10% ethanol gasoline. My old Harley Sportster hated 10% ethanol fuels and actually required me to add a lead additive to my gas or it wouldn't run correctly no matter what I did.

10% ethanol fuels are great if you have a fuel injected engine. They are not so great with any naturally aspirated engine. (God I love to say "naturally aspirated engine" instead of carburetor equipped). Those are grown up words!

[boovuc 1,090]

OK SOI............The answer to your question is...............................Nope!   

 

I spoke to two of our degree people today and the day before. Technically, since the ethanol is present and it is completely miscible with water, it won't phase out meaning that if you have gasoline with ethanol and I mean gobs of ethanol let alone the pump's 10% max content, the only layering or phasing you will see is that of gasoline and ethanol. Even if you throw in water, the ethanol will absorb it to a point where again, you will see a distinct layer of the gasoline and of the water/ethanol solution or ethanol/water solution. They knew of no dyes or indicators that would phase the three components in a single solution. You would only see two layers.

 

I believe what most of us have seen in the bowls of carburetors of small engines over the years is a water sludge left after the gasoline has evaporated and since the advent of 10% ethanol fuels, the remnants of ethanol/water left over after gasoline has evaporated away. (Remember that the gasoline will evaporate faster than the ethanol. The water would take much more time). Over time, I think that if you have a small amount of gelled gasoline/ethanol/water solution in the bowl, fresh gasoline won't absorb it or won't absorb it well and over time, it will begin to effect the float and other internals of the carb.

 

Just for s#%ts and giggles, find a wide shallow glass vessel like the bottom of an old butter dish and put about an ounce or two of regular 87 octane gasoline in it and let it evaporate. Do this a few times and I'll bet you'll see and mostly feel a film on the bottom of that glass surface.

 

My Kohler Twin when left sitting for two weeks needs a lot of cranking to start. I have also heard that from a few other folks here with KT17's in their C-175's and the 19 horse C-195's. I took my carb off the C-175 this Spring and never put it back together yet. If was full of gunk in the bowl. (Slightly yellow viscous gel). It will get all new fuel lines, a new tank valve and grommet and a new fuel filter. It may get a new carb since I have a fresh rebuild in a box.

The warmer the climate, the shorter the shelf life is on ethanol added fuels. Winter temps actually help keep the fuels stable.

 

I think there are Wheelhorse tractors that were built with susceptible carbs and fuel systems as well as many that can stand the abuse of parking it for the winter and firing it right back up in the Spring using the old gasoline in it without issues.

I don't do it with any of mine anymore.

[Save Old Iron 1,571]

Thanks Boo and Steve,

 

I think we have begun to provide a solid foundation for folks to intelligently discuss what a "bad gas " situation is and is not. I agree with the statement E blend can be an advantage as in many respects it "polices itself" of water contaminates. I still would love to understand why folks put a 30 day life on E blended fuels. In certain poorly regulated storage conditions,

 

Truth be known, when my father passed away a few years back, he left behind a bass boat with a full fuel tank. I brought the boat and the 40 gallons of 5+ year old gas to my home and started to use the fuel as an experiment. If this craps up the carb, I'll rebuild it. Well sir, I used nearly all the 40 gallons without any issues. And before you say it, I know my dad. The tank was full of the cheapest gasoline that existed in the Scranton Pa. area the day he filled up. I used to roll my eyes as he would tow the boat an extra 15 miles to another station that sold gas for 3 cents a gallon cheaper. So no! It was not av gas or marine gas. Guaranteed.

 

I can understand where extremely poor storage conditions can allow moisture or even water run to enter into the E blend and cause a phase change. I admit my storage conditions and containers are not always ideal but somehow I survive without issues. My alliance with the Seafoam and Magic snake oil gods be praised - Can I get a Hallelujah?

 

As far as dye for phase separation, I understand the diluted etoh will not separate further from the water when the E blend fuel to form 3 distinct layers within the mixture. I also understand the water soluble dye may tint the E blend fuel slightly when the etoh is properly dissolved within the gasoline. I also believe there should be a rather distinct change in this tint when the etoh / water does drop out of the E blend fuel. It is ultimately the bottom 10 - 15% of the container I expect to be most heavily colored with the dye when phase change occurs.

 

Do you believe there may be a natural evolution of rubber gasket compounds to become more etoh resistant?

Will the old rubbers be thrown out and new rubber compounds find their way into everyday use, maybe even gracing the individual components of the Kolher carb rebuild kits?

[Save Old Iron 1,571]

 

The next tractor chat topic of discussion should concern fuel stabilizers. Chemically, what do they do?  Do they just add even more ethanol into the gas to allow an even greater absorption of water and preventing a delay phase change?  Discuss...............

[gwest_ca-(File Mod) 11,762]

Thought these may be of interest to an old concern

 

Garry

[Save Old Iron 1,571]

Here is one item I'm adding to my list for defense against E blended fuels. Remember guys - stop grousing and get busy investigating how to defend against the effects. If we need to upgrade fuel lines to poly - do it. If you need to change your habits of leaving too little E fuel in the gas tank when you store the tractor for the week - fill the tank before you store the tractor - don't grouse - do it!

 

If you must leave the tractor exposed to the elements, find a way to prevent and water from entering in the gas tank. Is your fuel gauge lens cracked ? Then order one from Glenn and don't give water an easy entry into the fuel tank. Don't store your gas tank outside where rain water can intrude into the container. Stop whining - change your habits - look around and see where corrections need to be made.

 

I am going to investigate coating the exposed portions of the internal parts of the carb with  this

 

http://damonq.com/red-kote.html

 

I figure coating the inner surfaces of the fuel bowl and the "roof" of the fuel chamber above the bowl will certainly provide some protection against water oxidizing the aluminum parts of the carb and allowing oxide particles into the fuel system.

 

We will see how easy this will be to accomplish and how durable the finish will be.

 

I believe POR makes a similar product too. This one appears to be more easily applied. We will see.

[wh500special 2,352]

Well, I poked around a bit today in some catalogs for dyes and came up short. Maybe something will turn up later when I look a little deeper.

This weekend, I ran into a problem that had me almost rethinking my postulates on ethanol fuels....my wife and I took the boat out Saturday hoping to scratch a crappie or walleye. My motor started like it always does, but the more I ran it it developed a miss and died a few times. I swapped out the plugs hoping for improvement, but still running horribly.

A few guys narrowed my problem down to "bad gas" and ethanol on an Internet forum. A call to a local dealer, who listened to my symptoms and asked a lot of questions, suggested I have a bad fuel injector. I asked about the fuel issue and he said it was probably unlikely due to the pattern of symptoms I explained, but he said it's a popular go-to diagnosis for every problem encountered with an outboard today. Of course, this doesn't yet rule bad gas out. Anyway, the motor is going to the shop for who knows how long and for what cost.

The thing that got me was that the gas I am having problems with was brand new, so it wasn't terribly suspect to me. But after my boasts about never having a fuel problem I fear I might have jinxed myself.

So much for the charmed life.

Steve

[Save Old Iron 1,571]

Guess I really did not need dye to observe the phase separation. I finally had the opportunity to experiment a bit with E10 and adding water. Experiment successful !!

 

 

 

Click on the image to play the movie - yes, that is a layer of water + EtOH on the bottom of the container separated from the gasoline component on top. The container shows about 20% water and EtOH to 80% gasoline. That is pretty darn close to what you would expect.

 

 

Edited July 31, 2013 by Save Old Iron

[KATO 115]

WOW!!

[Save Old Iron 1,571]

Chem guys - can I calculate the lowered octane rating of the supernatant?  If my intent would be to use the now ethanol free supernatant, I wonder how much Premium gas I would need to keep the octane above regular grade octane when I added the supernatant to a quantity of Premium grade E10.

[wh500special 2,352]

Fuel octane blends more or less linearly.  If you blend half and half 91 octane and 87 octane you get 89 octane.  Most gas stations only keep high test and regular in their tanks and then blend at the pump to whatever is supposed to be dispensed.

 

I think Ethanol is about 103 octane.  If the E10 you bought was labeled as 87 octane, the resultant gasoline phase is probably close to 85. 

 

Let X=octane of gasoline portion of the mixture

 

(0.10)*(103)+(0.90)*(X)=87, solve for X.

 

The logic to this calculation is:

 

(volume fraction ethanol)*(octane of ethanol)+(volume fraction gasoline)*(octane of gasoline)=Octane of mixture

 

I'd bet 85 octane is high enough to run a lawnmower engine without a lot of complaint until it gets hot.  Then it might knock a bit.

 

Steve

Edited August 1, 2013 by wh500special

[wh500special 2,352]

I forgot to update my boating woes...

 

Nearly $700 dollars later, we can affirm that I had water in the fuel.  I didn't lose any injectors or anything, but it sat with water in it long enough to develop rust in my fuel filter canister which found its way into the two fuel pumps and all of the lines.

 

The service tech said ethanol was the culprit.  Maybe.  But we had a ton of rain and I'm thinking it's possible the tank breathed it in and I might have got the water from the bottom of the gas station's tank.  Anyway, some would say this is a smoking gun for ethanol phase separation, but I don't think there's really any way to know from the limited data available.  Could be; might not be.  No way to know for sure.

 

The service tech told me he couldn't believe the motor even ran on the fuel I was feeding  No permanant damage to anything and I used the boat last weekend without incident.

 

Didn't catch anything though.

 

Steve

[bowtieguy 334]

Steve...you can't catch crappie or walleye on cheap gas!!!.....try DY-NO-MITE....that chemical will literally make em' "jump in yer boat"!!

 

Sorry to hijack your thread SOI....but I have read all comments with interest...looking forward to your final report!