I am just getting started in Bio-diesel when I first looked in to it every one was talking about Methanol but now I hear a lot about ethanol is there any differences when it comes to bio-diesel?

Ethanol is a bit trickier to work with, and usually a bit pricier than methanol. Make sure your ethanol is Anhydrous (less than 1% water), and use KOH as the catalyst. Also note that the KOH will take much longer to dissolve into ethanol than it would into methanol. Use a bit more ethanol than you would methanol.


Ethyl esters (ethanol-based biodiesel) have much better cold-weather properties than methyl esters (methanol-based). Ethanol is also much more environmentally benign (meaning your glycerine, wash water etc is much easier to dispose of), much less toxic, and much safer to work with. It is also much more likely to have been produced from renewable source, meaning your biodiesel will be more renewable than if it were made using methanol.

But then again, methanol is easier to work with.

You'll have to use more catalyst too (for ethanol that is) - up to twice as much.

Myke
I've never heard anyone say more catalyst was needed for EtOH. Do your experiments show this? Does it indicate that the unwanted side reaction making soap is faster in EtOH? Or does it mean that EtOH usually contains more water which promotes the unwanted reaction?

Also, ethanol is a heck of a lot safer. It's the stuff some of us drink after all! What types of places should I look for anhydrous ethanol? BTW, the guys are correct, more KOH is needed to form EtOH than methoxide. Still this is what I'd like to use. I place a premium on safety. While you can make methanol safe enough with some effort, I'd rather be able to enjoy the process and not worry about buying the farm if I get the slightest bit of alcohol on me, or if I catch a whiff of the junk. Hopefully you guys will give me some feedback

I was also advised to use a lot more catalyst, but all I found was the mixture bound up into a solid gel.

A case of too much catalyst I suspect, but I used the recommended 10g for 1 litre using 250ml Anhydrous ethanol. Beats me, I will try it again with the usual amount. One thing that was pointed out also, was it is a lot easier to use ethanol with low FFA oil. ie titrates 1g of catalyst or better.

Be warned! If it works please let us know too!

Best of luck.

In fact, out of all ethanols obvious sterling qualities, about the only thing it does not do very well is make biodiesel.

Tilly SBC/IBA

"The Book" says use 3.5g od NaOH per litre of virgin oil. However most people find that 4 to 4.5g is better.

On top of that you need to add an amount to soap out the FFA. This amount is worked out by doing titration tests.

However, for most WVO, the catalyst levels are not really that critical. It's reasonable to do a range of test samples with varing "guestimated" additional NaOH. e.g. 5g, 6g, 7g and 8g per litre. The one with the best separation for the lowest amount of NaOH is the one to use for the main batch.

Myke and Mathew

Who told you to use more catalyst with EtOH? Did they give a sound reason for the advice, either a scientific explanation or experimental evidence?

I suspect that there may be some confusion here.

As you need to use KOH with ethanol rather than NaOH and you need more KOH than NaOH for a given volume of oil, some people are assuming that you need more catalyst when using ethanol.

Apologies if this is not the case.

H

http://groups.msn.com/Pinzgauerdiscussiongroup/homepage

If I recall properly a contact on the Yahoo list.

I found this info also on the journeytoforever pages, its was under making Bio with ethanol but I cannot find it at the moment. I was severly disheartened in my experiment. I obtained 1 litre of anhyd ethanol and this was my first real disaster making biodiesel.

Found the link
http://journeytoforever.org/biodiesel_link.html#ethylester

No offence or slight intended in mentioning this.

Matt

Now, who is it that has decided ethanol is better than methanol for making biodiesel?

Tilly SBC/IBA Drink the ethanol div

Yes it is confusing. It depends on whether you're using NaOH or KOH and working in moles or grams. If you use KOH to do the titration and the reaction you would use exactly the calculated amount for the FFA.

If you use NaOH for the titration and KOH for the reaction you would multiply everything by 1.403 to change to KOH if both were the same purity.

However there is nothing in this which requires more catalyst for ethanol than methanol. If you have been reading my posts you will know that my experiments show the reaction with methanol and NaOH works better with 5g per litre plus titration than with the usual 3.5. Perhaps with ethanol exactly the same thing applies. Where are the experimental results which enable one to graph yield and conversion against catalyst for ethanol?

With methanol 5g NaOH per litre of new oil is a good compromise between yield and conversion.

[This message was edited by neutral on 30 April 2003 at 12:56 PM.]

I dont think anyone said that ethanol is Quote, "better than methanol for making biodiesel"

It's well reported to be a real hassle, if only because of it's water content.

Thanks Neutral, I must say I was entirely confused when it said to use nerly 10g of KOH per litre of oil for starters. This in my limited expereince would cause sever gelling if using methanol, and it is exactly what happened to my ethanol experiment.

I did email the author, and I was advised that ethanol is less efficient? It needs more cat to get the reaction to happen/occur.

I resolved immediately to wind it all back to the same amounts used with menthonal next time.

I must try this one weekend, I have 0.75 litres of my ethanol left, it is a precious resource, even if you can't drink this type.

Matt

Just a note that may be of interest:

I know from my soap making experience that KOH provides a liquid soap (for pump packs, etc) while NaOH provides the more solid form. Is it possible that the higher/lower gelling temperatures attributed to eth/meth are in fact due to the predominantly used catalysts eth=K, meth=Na)?

Just a thought. But if it turns out to be correct, then we should be able to get good thermal behaviour from meth esters by using KOH as the catalyst.

Thoughts?

I think if I am reading the literature correctly, ethanol might work really well with fresh food grade oil. I plan to do a couple of test batches with ethanol soon, and I will perfect my technique with virgin oil before I even attempt WVO. I also wonder if using teh denatured ethanol with about 95% eth and 4.5% methanol would be better than the 200 proof drinking grade ethanol. Remember, that oil has to be thoroughly dried out for the ethanol method to have half a chance to work. According to the journey to forever site, "one half of one percent of water can kill the reaction." Good luck and let me know if you have any better results to report with ethyl esters. Don't forget if you are comfortable working with methanol, and have some of this noxious poison on hand, you can "force' the reaction by adding some methoxide to the mix.

That sounds a bit drastic.

I am not sure you can purchase 200 proof drinking ethanol.
The old Idaho web site did say that anhydrous ethanol denatured with petrol made did make biodiesel.

Tilly SBC/IBA

I am noy used to working with stiff where the slightest mistake could kill you. I'm sure for you and others using recommended safety procedures it isn't quite that bad. Yeah, you can purchase 200 proof ethanol with no denaturants in it-it is "kosher for passover" do I assume it's intended for human consumption. Would I drink it? No! But I basically don't drink anyway, just a little wine here and there. It could be diluted and you could drink it, but if you drank the straight stuff, I imagine your body would treat it like a poison. This company also offers 95 percent ethanol with 4.5% meth and other denaturants. That would probably also work. But it would be poisonous for the table. It sounds like you still need to be careful with the catylst even if your are making ethoxide instead of methoxide. The MSDS says that KOH can cause seevr burns and death and not to inhale the fumes at all. I will invest in an organic respirator either way and still be careful. The organic respirator will come in handy as I plan to restore a boat later in the year.

Tilly SBC/IBA