Sciencemadness Discussion Board - getting the ethanol out of E90 and E85

getting the ethanol out of E90 and E85

contrived - 27-8-2007 at 10:53

The governor of this (oh so green) state has signed a bill mandating all fuel sold here be E90 or richer in EtOH. Until some reason is recovered a lot of vintage motorcycles are going to be running on avgas, not at all or deteriorating quickly. The older seals just won't withstand the solvent effects.

I'm looking for a relatively safe and cheap way to get the ethanol out of the fuel. To be practical it has to be a fairly rapid, one step process. Distillation is out for safety reasons and probably wouldn't work anyway .. at 78-80 deg, ethanol sits in the lower middle of the curve.

Ethanol mixes with water so there's the beginning of an approach. I'm hoping to find a zeolite that will work as an ethanol sieve. I haven't run accross such a thing and don't know if anyone has tried but I'd be surprised if there weren't something in the literature ..

Anyway- I just heard about the mandate and started thinking about this last night. Anyone else got ideas ? I'd be up for a partnership and never have been stingey sharing money or credits...

Drone - 27-8-2007 at 11:20

I can also get E85 and have an interest in extracting clean ethanol from it.
I have only tried a few methods:

1) Slowing fractionating it: I got no clearly defined ethanol fraction. Even the lowest fraction (~60 C) had ethanol in it. I collected the fraction 75 - 85. It still had the same odour as the E85. On addition of water a suspension of non-polars formed.

2) Mixing equal volumes of water and E85: I added water to the E85 until the suspension of NPs stopped increasing. This turned out to be about equal volumes of water and E85. After a few days 2 layers formed and could be seperated. The polar layer still had a foul odour. This seems to work, but the ethanol would have to be distilled out of the water.

A particularly useful property of E85 is that it has a low water content. So if a method of extracting the ethanol from the fuel is feasible it could be a quick route to dry ethanol.

Thinking about. 4 Angstrom molecular sieves absorb ethanol. So it might be worth attempting to saturate the sieves in fuel and them bake them to remove the ethanol.

[Edited on 27-8-2007 by Drone]

evil_lurker - 27-8-2007 at 11:56

One could possibly add concentrated sulfuric acid to the E85 forming ethyl hydrogen sulfate.

I'm assuming that the aliphatic and aromatic components would not react to the sulfuric acid and would form a bilayered solution which could be seperated off rather easily, and/or distilled at low temps (sub 90ºC) to remove most of the aromatics.

If heated more it would form diethyl ether...

not_important - 27-8-2007 at 12:49

E90? In the US? Fat chance. I think you'd better read the legislation in question, all such bills that I know of go no further than Oregon's :

Quote:

The major components of Bill 2210 include that all gasoline sold in the state must be blended with 10 percent ethanol after Oregon production of ethanol reaches 40 million gallons per year.

which means they must ramp up ethanol production to that level first.

If it is indeed E90 that will be sold, then the best way to get ordinary gasoline from it is to put it in you fuel tank and drive to another state where you can still buy ordinary gasoline. At E90 the remaining hydrocarbons are going to be more for lubrication than being good fuel, if you could wisk away all the ethanol the remaining 10% is going to be piss poor gasoline, likely knock badly, and just be near to paint thinner as a fuel.

The problem with absorbents is in their regeneration. For pulling the 10% of alkanes out of E90 I suspect that pervaporation with a very non-polar membrane might be the best route.

That holds true for cleaning it up for the ethanol, too. While adding water will result in most of the hydrocarbons spearating, you'll need to add a lot of water to minimise the amount of alkanes dissolving in the water-alcohol layer. After the separation, careful distillation should remove most of the remaining hydrocarbons as azeotropes, leaving a dilute solution of ethanol in water.

chemrox - 23-9-2007 at 21:05

"after Oregon production of ethanol reaches 40 million gallons per year."

I find that comforting because I also have a vintage motorcycle that won't like E90. I think the idea of mol. sieves is probably the way to go though...zeolites are the cheaper sieves .. maybe even the one in the hardware store will do it.

Someone here and I were planning to experiment with a zeolite column that could be engineered to become an inline appliance and could be stashed under the fuel tank or on the frame somewhere.

I'm not clear on how to discharge the captured ethanol but am sure that will become apparent with more reading. I don't see Oregon farmers giving up the lucrative grass-seed trade for ethanol crops anytime soon so it's a back burner kind of project.

[Edited on 23-9-2007 by chemrox]

Eclectic - 23-9-2007 at 22:14

It sounds like he is talking about E10 and E15. Recovering gasoline from E85 and E90 doesn't make ANY kind of sense.

What kind of seals can tolerate mixed hydrocarbons but can not stand up to 10% ethanol? Shellac? If there is such a sealing material used isn't it more practical just to replace the seal with a compatible material?

Using E85 as denatured ethanol should work fine for estherifications if you fractionate using a good column. Cleaning it up to be drinkable might be a bit of a problem.

Antwain - 24-9-2007 at 02:00

They have just jumped on the ethanol bandwagon here in Australia. They sell E10 fuel at prices ranging from ~3% more to 2% less than regular unleaded. Considering that its not just not an idea fuel for engines not designed for ethanol (forget fuel consumption, which I have heard can rise by over 15%, but I don't know if thats true) I never use it.... even though its "recommended for new engines". Also they sell E40 as "performance fuel" for the stupid hoons to buy for like 50+% more.

Anyhow, I have always figured that its easier to buy ethanol as 'methylated spirits'. In Australia, as best my research has shown, they only use bitterex and no methanol, but I don't know how this applies to the rest of the world. On a per litre basis, metho is about the same price as petrol. I just chuck in a small amount of sulfuric acid to sequester the bittering compound, distill off 90% or so of the stuff and chuck the rest. This also removes a little bit of the water, as shown by the temperature rising to ~100 if you do try to distill the last 5-10%.

As for removing ethanol from fuel for the sake of my poor car, I don't need to worry yet, but when the time comes I cant think of an easy way of doing it on that scale

JohnWW - 24-9-2007 at 14:42

How much sulfuric acid per liter of "methylated spirits" do you use to sequester the bittering compound added to it? What is "Bitterex" chemically? The only reference I can find for Bitterex on Google which says what it is states that it is extracted from "bitter melon seed".

[Edited on 25-9-07 by JohnWW]

not_important - 24-9-2007 at 15:00

Quote:

Originally posted by JohnWW
... What is Bitterex" chemically?

http://en.wikipedia.org/wiki/Denatonium

BromicAcid - 24-9-2007 at 16:51

I remember seeing kits sometime back for testing the amount of ethanol in gasoline. They included a graduated cylinder (whose graduations had a gap at the begining) and a blue colored solution. Basically you put the solution in the graduated cylinder to the first line. Then added the gasoline and used the stopper for the cylinder and shook it. You ended up with an aqueous phase and a organic phase and the aqueous contained the ethanol. And it was blue so you just measured the volume of the blue phase. I figured it was just food coloring and water. From what I understand, if there is only a few percent of water it is impossible to blend ethanol and gasoline, they just separate. At least that was my understanding.

I know drone already mentioned this, but maybe less H<sub>2</sub>O would have to be used than he used so long as one gave it enough time to seperate. Of course you still have the problem of water in your ethanol though. Maybe some sort of polyol might work and then distillation could be accomplished simply. Or like evil_lurker suggested, sulfuric acid.

Ozone - 24-9-2007 at 18:07

I'm with Evil_lurker on this one. The problem, though is the same one you have with biodiesel made via acid catalysis. Removal of the acid. I know, wash it with water...But then you have to dry it...

Solid phase might work. I know for a fact that Ether can be made in high yield this way from ethanol.

You could run it through a strong acid cation exchange resin at elevated temperature and then flash off the ether.

I think that a continuous process may be feasible here.

Alternatively, you could partition it against salt. Just make sure to distill it afterward to avoid putting salt in your tank (oops, more than one step). Yep, partitioning vs. water is a viable strategy (with similar problems)!

Are we included in the patent of a one-step ethanol removal strategy that does not involve distillation? Imagine the isolation of ethanol or diethyl ether from stillage w/o distillation of a product boiling at ~78°C...

Cheers,

O3

Drone - 25-9-2007 at 01:24

Quote:

Originally posted by BromicAcid
I know drone already mentioned this, but maybe less H<sub>2</sub>O would have to be used than he used so long as one gave it enough time to seperate. Of course you still have the problem of water in your ethanol though. Maybe some sort of polyol might work and then distillation could be accomplished simply. Or like evil_lurker suggested, sulfuric acid.

I have recently tried this. to 100ml of the fuel I added 15ml water. A milky suspension was formed. Over about 3 days it mostly cleared up. A small amount of curdy white precipitate had settled out and a small upper layer of hydrocarbons had formed. I separated out the aqeous layer and filtered it to get a clear liquid.

Addition of 1 drop of water to this caused more of the suspension to form, so I added another 40ml of water. The milky suspension was back. I separated the aqueous layer again, but any addition of water still caused the suspension to reform.

Trying to distill this liquid still results in azeotropes of ethanol / hydrocarbons at 73, 75 and 76.5 degrees before the ethanol / water starts to come across, showing there are still considerable amounts of non-polars in it.

I have currently fractionated 1.5L of the E85 and saved the fraction between 73 and 79 degrees (1.1L). To this I have added 2L of water and retained the aqueous layer. I am planning to distill this and see what quantity of hydrocarbons remain.

Eclectic - 25-9-2007 at 04:10

An extraction of the distillate between 70-80F with VM&P naphtha might remove most of the low boiling hydrocarbons without having to add water. Then redistill and treat with activated carbon.

Drone, how much hydrocarbon layer did you get from your 73-79F fraction after mixing with water? Would this be a practical source of hexanes (pet.ether)?

[Edited on 9-25-2007 by Eclectic]

contrived - 26-9-2007 at 14:23

I'm working with CRX on this. We want to get a removal scenario that doesn't require a lot of steps or equipment. The goal being to have something that could be used at the gas pump or on the vehicle. However, unless Oregon kicks up EtOH production its not going to be a lucrative project.

not_important - 26-9-2007 at 16:18

Well, you never did come back with an answer as to is it really E90 or E10. If it's E90 then there is no way because the hydrocarbon portion just isn't very close to decent gasoline.

If it is E10, then 4A molecular sieves are likely to do the job, it might be better to have a preliminary bed of 3A to remove water followed by the 4A bed. This could be done with an in-line filter.

Note that molecular sieves are zeolites. The common cheap desiccant zeolites that don't have the 'molecular sieve' tag are not selective enough to use to separate ethanol out of E10, they will absorb many of the shorter chain hydrocarbons as well.

Regeneration would likely be done by blowing steam at 100 to 105 C through the sieves for some time, switching from steam to preheated air and slowly raising the temperature up to 230 to 250 C for awhile, switching to dry air, then pulling a vacuum on the hot sieves for 15 minutes, sealing them off, and letting them cool. The stream will carry off any trapped hydrocarbons as well as the ethanol, and will need to be processed to prevent those from entering the environment.

Antwain - 27-9-2007 at 09:04

@JohnWW -

I added ~10 to 20mL of conc. H2SO4 to each 1L bottle of metho, recapped and shook well, then added 5L through a dropping funnel, 100s of mL at a time, over the several; hours the distillation took. The last liter that came across smelt very weakly odd, and not like bitterex smells if you dry metho and heat the crud so it was probably hydrolised (serves it right). Also while the last liter which smelt funny is now used only for washing glassware, the 300mL which I didn't distill across smelt downright awful and potent. It went straight down the drain followed by some bicarb.

JohnWW - 27-9-2007 at 13:25

Thanks, Antwain. Do you mean you distilled 5 L of acidified "methylated" spirits at a time, from a 5 L flask heated on an electric rotovap? Also, you would have to be careful when adding the concentrated H2SO4 - its reaction with C2H5OH, depending on the concentration and temperature, can convert it to either (C2H5)2O (which is more volatile and hazardous than alcohol in which it is soluble, boiling at 30ºC) or dehydrate it further to C2H4 gas. However, the water present to the extent of 5 to 10% in the spirits would reduce the possibility of such reactions, but it means that the H2SO4 would have to be added very slowly with stirring because of the heat liberated due to hydration.

BTW If Bitterex is non-volatile even without acidification with H2SO4 (which probably converts it to the hydrosulfate if it is a free-base plant alkaloid, which however would be more volatile than the hydrosulfate), and is the only adulterant that so-called "methylated" spirits contains to make it unpalatable, then it should be possible to purify it from the Bitterex simply by distillation, without acidification. However, it would still contain 5 to 10% water, which the H2SO4, especially if in excess, would reduce in the distillate due due to the salting-out effect.

[Edited on 28-9-07 by JohnWW]

[Edited on 28-9-07 by JohnWW]

Antwain - 27-9-2007 at 18:46

My reasoning was as follows: if you could make drinkable alcohol by simply boiling and condensing metho (<$3AU/L ----> ~$1/L * 40%, ie $1 per liter of vodka) then people would. And I would have heard about it. Therefore it follows that despite its large molecular mass bitterex is volatile, or forms an azeotrope of sorts with ethanol. Having an amine group, reaction with a strong, non-volatile acid would likely cause it to not be volatile. If it was hydrolised, and something did come over, it will still only be ppm. Best case scenario, it is removed completely, worst case there will likely be less crap in my distillate.

I distilled from my largest RB flask, 1L, keeping the level above 500mL so that the 'crap' never became concentrated enough to raise the temperature.

I added to sulfuric acid directly to the metho bottles so that for each amount of bitterex + water added to the distillation flask an equivalent amount of acid was added, and so that the acid was never concentrated (ie to make ether and other non desirables). When I addded the acid, the 1L of metho became vaguely warm (15*C temp rise, maybe) and misted slightly, no violent reaction.

chemrox - 27-9-2007 at 21:20

I'm working on this with contrived.
@Not-important:

"Well, you never did come back with an answer as to is it really E90 or E10. If it's E90 then there is no way because the hydrocarbon portion just isn't very close to decent gasoline."

In local parlance, E90 is 10% ethanol, 90% gasoline hydrocarbons. I think E10 would be better nomenclature for 10% EtOH but there it is.

But as to shaking methylated spirits with H2SO4 and distilling it, aren't you making ether? Sure sounds like the ether process to me.

Eclectic - 28-9-2007 at 00:07

Your "local parlance" is backwards to the rest of the country and the automotive industry. E85 is 85% ethanol, 15% hydrocarbons.

E85 Flex Fuel

chemrox - 2-10-2007 at 10:28

I was wrong! E85 is indeed 85% ethanol in "local parlance." I misunderstood the flier-reading too fast. Mea Culpa!

The Oregon madate is all fuel to be at minimum ethanol content- E10. And as was mentioned; ethanol production has to go up to 40M/year but that size plant is going in to Boardman this year. So even if Boardman falls short, it's likely state production will make the mark and we'll be stuck with E10.

[Edited on 2-10-2007 by chemrox]

Eclectic - 2-10-2007 at 19:22

Which is unlikely to harm your antique engines any more than the oxigenates currently in unleaded fuel...

engine harm

chemrox - 2-10-2007 at 20:19

Several people I know through an antique/vintage bike organization have stated that their engines were harmed by E10 ethanol. The reported damage involved or was caused by compromised seals that were attacked by the ethanol. "Other oxidizers' may not be so hard on the rubbers and polymers in the older engines. The same concern came up with aircraft engines and av gas is going to remain E-free. You may see a lot of BMW's and Moto-Guzzis line up on the tarmac at general av airports in the short term.

evil_lurker - 25-10-2007 at 12:19

I finally got my hands on some E85 and decided to see what would happen when 30ml was added to 30ml 98% H2SO4.

There was some scorching as I had feared, but what really amazed me is that it formed a quad layer mixture.

Definately odd.

chemrox - 25-10-2007 at 22:11

Damned interesting! Now I must ponder it. That looks like a pretty huge condenser behind the graduate old man.

evil_lurker - 26-10-2007 at 11:13

The thing behind the graduate is a 1L jacked reaction flask. Got it off Ebay for $65 along with a freebie 4 neck head.

It looks like the answer to the problem is going to be adding warmish hot water, seperating in a funnel, and distilling, which ain't exactly ideal considering the EtOH azeotrope.

As an expirement, 1000ml E85 was added to 1000ml of water. After allowing to seperate for 20 minutes, exactly 175ml of gasoline was recovered.

I'm going to distill it this afternoon and see what I get... hopefully it will clean it up some.. there is this really rank smell of "rotting potato" and gasoline left over after seperation.

I really need a bigger reflux column (around 500mm) and flask in 29/42 joint for doing EtOH distillations but that will have to wait until I can come up with some more fundage.

Eclectic - 26-10-2007 at 12:55

You could try extracting your 50% Ethanol fraction several times with a small quantity of VM&P naphtha before distilling to remove residual low boiling hydrocarbons.

Antwain - 26-10-2007 at 13:11

What exactly is the goal of extracting the EtOH?

Never one to discourage experimentation...but, i think this may be barking up a useless tree. I can't see this being an economical route to ethanol, even in countries where methylated spirits contain MeOH. And I wouldnt want to put stuff that had been anywhere near mineral acids into my car.... If you think ethanol is bad just see what H2SO4 will do to the engine.

Also, you know that olefins (AFAIK) dissolve in conc. sulfuric acid and possibly visa versa. I believe it involves addition across the double bond. Hydrolysis will then probably??? give alcohols.

evil_lurker - 26-10-2007 at 15:56

The goal of the EtOH is suitable feedstock for conversion into diethyl ether.

Taxes on food grade pure grain alcohol run $27 per gallon making it prohibitively expensive. Common off the shelf hardware store denatured usually contains 49% MeOH so that is out of the question as well. Specially denatured is even more of a rip off, usually they want taxes and hazmat shipping fees.

If only 1.5 liters of good clean EtOH could be extracted from a gallon of E85 that costs $3, then it would be great.

I'm not sure if it would be worth it to extract the low boiling fraction. 100ml of the heads fraction from the 1.375L was cut and added to water. Approx 12ml of low boiling hydrocarbons was seperated out. Its interesting to note that the condenser was dripping even before the temp hit 50ºC. There also seems to be some sort of azeotrope from 75-77.5ºC

So far I've managed to distill off about 500ml of 2750ml water/E85 having a boiling point less than 79ºC by going veeeerrrryyyy slowly. Which is OK since there ain't much babysitting it... the still is pretty much able to be left unattended since I'm using a heating mantle and so the heat stays rock solid steady.

I figure after I catch 2L or so, I'll carbon filter it, redistill and try to get a liter of azeotrope, then run over molecular sieves till anhydrous.

Antwain - 26-10-2007 at 18:34

Surely seperating MeOEt from Et2O is not that hard. Me2O is a low bp. gas, and if you only want it as a solvent then some MeOEt dissolved in the Et2O will not present a problem... Its got to be easier..?

Also are you sure that only EtOH and not MeOH, PrOH or iPrOH etc will be present in petrol, which is usually a complex concoction.

Edit- and at $3/gallon, perhaps you could send some my way.... over here its AU$1.40/L and I would dread to buy petrol in europe

[Edited on 27-10-2007 by Antwain]

not_important - 26-10-2007 at 20:37

Check the azeotrope tables. Many of the hydrocarbons in motor fuel also have azeotropes with water, and most have them with ethanol; heptane and ethanol have an azeotrope boiling at 72 C or so.

Certain denatured alcohols do have a lot of methanol in them, it appears that "Klean Strip" is one of the half-and-half types. But others have 10% or less methanol, a few have none.

http://www.distill.com/specs/EU2.html

http://www.sodes.fr/Pdf/fdsgb3r1.pdf

http://www.sciencelab.com/xMSDS-Alcohol_denatured_with_IPA_a...

http://www.customs.govt.nz/about/News/alcohol+150404.htm

http://www.ifa.hawaii.edu/instr-shop/MSDS/Klean%20Strip%20De...

http://www.pharmco-prod.com/pages/MSDS/RA_Denatured_190.pdf

denatured alcohol that has a low percentage of methanol
http://alcoholsoaking.blogspot.com/2006/03/alcohol-brands-an...

If you make ether with alcohol containing both ethanol and methanol you will get aq mixture of dimethy-ether (bp -23 C), methyl-ethyl-ether (bp 7.4 C), and diethyl-ether (bp 34.6 C). For most purposes the condensate from such a preparation will work as well as pure dimethyl ether, the main concern would be the loss of ethanol as the mixed ether.

Ethanol is likely to be the alcohol used in petrol in the US, current legislation providing support for large agriculture companies promotes the production of ethanol from crops, methanol and isopropanol are petrochemical products.

[Edited on 27-10-2007 by not_important]