Not sure if this has been discussed. Has anyone tried washing by distillation with ethanol? It would probably be harder to reclaim ethanol of a reusable purity due to the closer boiling points of ethanol and water. But then again, no water wash, no emulsions. No?
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Personally I suspect that the risk of reverse reaction would be higher with ethyl esters because there's so much more glycerine suspended in the batch.
I see this because on my first wash on batches that separated well and had settled for several days, I still got brownish water as though I hadn't removed the glycerine properly.
But that's just speculation on my part.
I asked the same question on one of the UK biodiesel sites where a lot of people have experience with Graham Laming's distillation-settling process, and apparently one guy might be doing ethyl esters and GL1:
A few notes:
We've been working with some novel processes here in Davis, CA using ethanol and KOH. So far as I can tell, anything over 28% by volume of ethanol is excess. We see no improvements in conversion above 30% and we see some reductions below 28% so ... that has been our observations over the past year.
As far as separation, washing, soap formation, etc. I suspect you will need to flash off your excess ethanol before attempting any type of wash. Your catalyst is concentrated in the (dissolved in) alcohol and as soon as you add water, boom, the catalysts waves goodbye to the alcohol and seeks out oil molecules.
Re: the color in your wash water ... again, this is probably due to remaining alcohol rather than glycerin. Our tests are on a process which converts glycerin in suspension to create a BioDiesel with a depressed gel point, so I can't guaranty that we are not seeing "glycerin" come out, but our wash water before flashing off the excess alcohol was always nicely colored. After, no color.
My last comment ... and hopefully you can put up more info on the solar zeolite driers you found in Fiji, but ... Don't bother to dehydrate the ethanol until after you mix in your KOH ... then run it through the Zeolite to suck out the water! This should give you a nice reaction with virtually no soap or settling problems (more likely due to soap in suspension than alcohol in suspension).
One last tiny tidbit, it may be that the larger ethanol molecule can divide and recombine in side reactions during your processing. We are using ethanol denatured with 5% methanol and unfortunately our process is designed to create useful side reactions from the time we start pretreatment of FFA's to the time we recover the excess alcohol, so I can't promise you will get the same effect, still, considering the conditions available with K or NA in your solution, some amount of H+ and OH- as well as H2O ...probably a bit of heat and mechanical activity .... you can theorize that the components are there to create simpler alcohols out of more complex ones
how were you testing for conversion there?
Are you up for a visit and a chat about this stuff while I'm in California, which is going to be a lot this spring?
I was doing experiments with water-containing ethanol and KOH catalyst, which yielded more soap but had easier separation than water-free ethanol did. However, I didn't have a good way to test for conversion, so I dont' know that I was actually making very good ethyl esters.
However, it's been pointed out that water should interfere with the process of making ethoxide when you mix KOH and ethanol, because mixing KOH and ethanol releases water, meaning presumably that this is a reversible reaction, meaning water from any other source (like water in the alcohol to begin with) will interfere.
Are you finding otherwise, or am I misunderstanding something of the ethoxide chemistry and the source of the water when making ethoxide?
Re testing conversion: We run a sample through with additional KOH and ethanol to check for any additional bound glycerin. Since most of our work is on the equipment and special processing methods, we don't make much quantity yet. We are just reaching the point of needing to go to lab testing on our results but have yet to hook up with a partner to fund this.
As per your ethanol/water question. One of the processing problems in our mix is how to use ethanol and oil with water in it. I can't publicly tell you how we are working on this, but we have a couple of solutions. The one thing I mentioned was to run your "ethoxide" through your zeolite _after_ mixing ... this should dehydrate your ethoxide and solve your basic water problem. Your KOH doesn't care if you mix it with water or ethanol ... your oil does, but you will solvate your Potassium with either one. It is the Potassium Ion that you need to drive your transesterfication reaction.
I'm noting that post transesterfication processing with ethanol is extremely temperature sensitive. If we try to Precipitate out Potassium with Phosphoric Acid or wash the BioDiesel while it is still warm, Soap forms very easily. So far, the only way I've found around this is to flash off any remaining ethanol and then let the Bio cool. Not yet sure what the max temperature is. We had a bad batch just last week when we tried a new evaporator setup ... could have been poor distillation or warm fuel. Oil + Potassium + water + heat is a standard liquid soap recipe. Since we almost always have water in the Phosphoric acid, I'm leaning towards heat as the initiator of the soap formation when we precipitate out our Potassium.
Not sure why anyone would want to come back to CA after leaving for the East, but I'd be glad to compare notes if you are out this way.
Oh yes, most of the time if we are not getting a good reaction, you will be able to see a separate oil phase after settling. You might want to simply invest in a cheap lab (test tube) centrifuge and put some samples in to speed up separation. Honestly, we decided at the beginning not to work with Methanol so I can't tell you if you will get the same. For us, our initial oil measures 92 - 93 with a hydrometer. Our finished Bio runs from 87.5 - 89 (again, we are doing some unique processing so you may read a bit different).
(edited to correct spelling errors ... sorry, I'll try to use spell check next time. Ed)This message has been edited. Last edited by: mensafarmer,
Pick up any lab book from basic to advance chem and you will find NA and K being dissolved in Water.
The basics should be that water the positive Alkali Metal Ion, either NA+ or K+ is attracted to the polar Water molecule more than Neutral NA or K.
Simple alcohols are similar polar molecules and work the same way. Your NA+ or K+ exists in solution rather than bonded to water or alcohol.
With this in mind, water in your alcohol will not prevent KOH from dissolving. In fact, Water will speed up dissolving your base. Problem is, you will be left with water in your "ethoxide" and the water you start with will be brought in to your reaction. You will have less alcohol by volume since some of it is water and water tends to keep your Na+ or K+ from being available to the triglyceride as a catalyst. When it does get free, then you have water sitting around available for bonding with your oil.....
....so, I suspect that water in your ethanol at the beginning would lead to a reduced reaction and at the same time help you make as much soap as you have water and catalyst to support.
As for making water with ethanol and KOH, should not be any worse than with methanol and KOH ... simply easier to find "dry" methanol than ethanol ... IMHO.
Hey guys, I've been making some ethyl esters in my Appleseed. The batches have failed 3/27 with ethanol or methanol as the solvent. They are too thick and obviously still hold some glycerides. The viscoscity is similar but slightly thicker relative to methyl esters, color is slightly darker. Burns well, not much smoke emissions, good power, good mileage, no excessive cold filter plugging. The last 2 batches have been with 2-stage base, and washed really easily. The ethyl esters have been harder starting especially with colder weather. I've been using 20-22% ethanol by volume, using 98-99% pure ethanol denatured with 1-2% RUG, and 7-9 grams of NaOH plus titration. I've had to use water to force separation. Maybe for the next batch I'll use 28% ethanol and maybe a trace of methanol in my next batch, unless this latest batch passes 3/27. I REALLY don't want to go back to methanol, but I am getting just a bit frustrated.
My latest batch described in the last post had a slight amount of dropout with the standard methanol 3/27 test, passed with ethanol so its probably a bit like turbinepowered's fuel. My other batches have been miserable failures with methanol 3/27 and had significant dropout even with ethanol 3/27
In looking at your numbers, I think you are under on your ethanol.
Not sure if you are using 20-22% by volume of 98% ethanol? If so, then you are not accounting for the RUG (regular unleaded gas) that will not be involved in your reaction. If this is the case, then your 20% by volume becomes 20 x .98 = 19.56% and your 22% becomes 22 x .98 = 21.56%. Both of these sound low.
I'm also not sure how fresh your ethanol is. Since ethanol tends to suck up water pretty easily, this could be a problem since you are already low on alcohol. While you can dissolve your catalyst into the water in your ethanol, you are going to get a double whammy by reducing your ethanol further based on the percentage water present in the ethanol AND loosing the amount of catalyst the water has dissolved.
So, I would first up the alcohol. Not sure if your last post referred to better results @ 28% or if you had yet to try that. Remember, 28 x .98 = 27.44% and if you are unable to determine you are getting totally dry denatured (ours comes in 55 gallon drums sealed @ the factory) then you should probably knock off another percent or two.
If you think you have wet alcohol, increase the KOH.
So I'm confused, you posted that you were using wet ethanol and I'm thinking you were doing this to get a good glycerin separation.
What kind of stock were you working with? How much water did you add to the ethanol? Were you trying a 5% prewash or adding the water to your ethanol before mixing w/ your KOH?
I haven't tried producing glycerin on purpose since last summer but I recall adding a small amount of Acetone to the oil before processing increases separation speed dramatically.
It sounds like you are working on something with a high FFA content since you mention using an Acid Base process. Are you sure of your numbers for the amount of base needed to neutralize your initial acid (our most common problem resulting in under processed BD ... soapy and impossible to wash)?
Ed that batch was in the 20% range, the one with the better results. I made one last night with 25% alcohol, using 10 gallons of ethanol and 5 of methanol. We'll see how that batch works on the quality tests. I had to force separation with glycerin and water. I'm rfeally a bit surprised that with that much methanol involved, the batch didn't just separate like a traditional methanol batch. yes, I believe my ethanol has a percent or two of RUG in it and I have not been adjusting for that. I've been assuming that the difference is just too small to worry about. My ethanol is probably still pretty dry, but I bet it has a percent or two of water by now. I bought it in late December. Getting close to time to get some more. Almost have used all of it.
I'm posting a link, not sure if it will work or if you will need to cut and paste.
The link is to a paper (no date) from the University of Idaho Re: the use of Ethyl Alcohol, and specifically quantity needed for completion of processing.
After reading their test results, it makes sense that there would be problems with Glycerin separation as well as testing of product using the 3/21 approach if you are under on the amount of alcohol.
As I posted earlier, we are getting good results with ethanol in the 28% - 30% by volume range. Less than 25% and a lot of things happen.
In thinking about the problems in this thread, I don't see any co-solvency type of activity indicated, at least not enough to generate the types of problems being reported.
More likely, there is a lack of conversion due to process water, the breakdown of ethanol during processing and potentially going under the needed quantity of KOH.
What we are seeing here, and again, we have some different processing features so results may vary, is that as soon as we get a complete conversion, we can separate out some of our excess alcohol and anything else we might be trying to make. This starts within a minute or two of stopping mixing and is typically 90%+ complete after 30 minutes.
All three components, Ethanol, Potassium and Glycerin prefer water to Oil and unless there are special steps taken, you will need to increase Ethanol and Potassium to account for water in order to achieve complete conversions.
What I've worked with in the way of underconverted oil to date makes a mean emulsion, lots of soap and takes days to weeks to settle out if you try to wash it with even moderate mixing.
Ed, I've got another batch going on out there right now, this time we're in the 28-33% by volume range with the ethanol. It will be interesting to see if I still have to force separation with glyc/water and then we'll see how the conversion tests go. I have not had too much trouble with washing and drying with the fuel that has failed the methanol 3/27 tests. It is not grossly underconverted it is somewhat(who knows how much) short of ASTM spec. It burns well in my 6.9 IDI runs just like methyl esters or D2. Are you saying that you have to flash evaporate your excess ethanol off before you can get separation? What sort of technique do you use to evaporate the ethanol off?
No, I'm not saying that you have to take the ethanol off before you can get separation.
I am suggesting that problems with separation are probably related to remaining ethanol, mono and diglycerides in the Bio.
The process we are developing is not one where we separate out Glycerin. We add to the typical BD processing to convert the Glycerin into a useful part of the process ...using it up... as we process. Because of this, we don't have a lower glycerin phase, instead we have an upper phase of surplus liquid alcohol which we decant off.
Since we are experimenting with various things like finding the lower temperature for the process to work, we get more normal things like a BD w/ glycerin. We also started the current experiments by making typical BD w/ Ethanol but we have not intentionally done so since last summer.
So, I'm taking our year old information and adding to that the chemistry of what we've been doing since then. Since we need to remove the Glycerin and make a new ester in order for our process to work, it is more demanding and tends to amplify problems with transesterfication.
I did a 3-27 test on the last 2 batches we did here and they indicated we had a complete reaction although this is not a definitive test for our final product.
We've found that testing the change in specific gravity and measuring the byproducts and products gets within range. We tend to produce soap from any under reacted oil so there is also a pretty positive visual indicator for us.
Just curious here. I work in an ethanol plant and am preparing to make BD at home... I know the difference between E85 that is sold @ the pump and the 200 proof that we make at work.
Has anyone tried using 200 proof ethanol instead of E85 to make BD? If so what were the results and what are the ratios needed?
Eagerly Await Reply,
Take some time to study these forums -- your questions and more are all addressed.
Learn how to make biodiesel with methanol first -- it's much easier.
200 proof ethanol is better than E85 for biodiesel.
As provo says there are lots of threads here that can help.
Down here in OZ there are a few of us that are using the OCH Master Formula with great success since it is easy to buy 99.7% pure ethanol (Methylated Spirits), in most hardware stores and cheap too. I understand though that the ethanol in Methylated Spirits in the US is not as pure.
However with you working with 200 proof, that won't be your problem.
Take a look at http://biodiesel.infopop.cc/eve/forums/a/tpc/f/719605551/m/555604723/p/1
You can read both sides of the story there. So far we have used this fuel in generators then went onto forklifts then onto bobcats then isuzu trucks and will soon be using it in Landrover Discovery TD5's.
We are also about to send off samples to a NATA approved testing facility to compare it to other bd versions for viscosity, etc.
Finally, for us it is easy to make, you make sure that your waste oil is "dry" then follow the formula. It's that easy and with this method not only do you get more fuel than the traditonal method but you also don't even end up with any by-product to get rid of.
Anyway, take a look and draw your own conclusions.
Good luck either way and welcome to the forum!
I dont know if this will be of any use but here goes.
The molar ratio 5.1 : 1 ethanol : oil
And the excess should be 70%
I don't know what oil your using so i can't calculate it for you but it should be volume wise a little less than methanol bio production which is 6:1.
Hey, and ethanol is supposed to be much more miscible with oil than methanol.
Ooops, I think there is still some humble pie in the fridge!
I have been reading this thread more thoroughly in the time since my last irrelevant posting and iv'e had a couple of thoughts.
I make the stochiometric equivelent for ethanol use (using a molecular weight of 282 (rapeseed))
as 16.3% mass / mass.
This is probably not far out for you guys in the US using Soyabean oil which from what I can see is arround 280.
I am using a molar ratio of 5.1 : 1 for ethyl ester production which is the literature value.
Comparing that to methyl esters which uses a 6:1 molar ratio methanol to oil that works out to be roughly 60% excess to the stochiometric equivelant using methanol.
Remember, the excess is only there to speed up the reaction and help drive it to completion - it is not a strict requirement and can be varied depending on reaction conditions.
Sooo... a 60% excess using ethanol works out to 33% by volume of ethanol to oil (282) ps- i'd add this over two stages 70% ist 30 % second, with a glycerol drain in between.
The fact that some ehtyl ester producers are using less than the methanol 60% XS I think is due to two reasons.
First, ethanol solubalises oil better than methanol and we start moving away from a micelle type reaction mixture seen with methanol to something more homogenous.
Second, I think the ethoxide species is chemically more stable than the methoxide species and is less likely to form side reactions with water and or ffa due to the electron donor effect of the extra methyl group.
Has anybody seen slower reaction times or increased temperature requirements?
If your having problems washing you haven't done the reaction properly ie: youv'e not made a high enough ester content.
There is no extra water contribution using ethanol than methanol therefore the increased soap content some people are seeing is wierd.
I'D appreciate any observations / experiences you have with washing / making ethyl esters because I'm about to make some from bio-ethanol and I would welcome any comments/ experiences youv'e had to date.
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