Help! I have been making BD for a couple years now and started with new fresh oil which I pressed from this past summer, so it's clean and good. I titrated numerous times and have now made a few mini batches from the new oil. The reaction seems to be great BUT I have noticed a thin layer of water between the fuel and the glycerin. Why is this?? Can anyone help me figure out how to remove it? Any ideas will be helpful. Thank you!
Are you absolutely certain that it is water ? The glycerine layer is very hygroscopic, meaning it readily absorbs water, so for water to be sitting atop the glycerine is unlikely.
What you may have is un reacted oil. Are you sure the titration value is correct and that sufficient caustic was used in the reaction? Next on the list would be the quality of the caustic; has it been exposed to humidity which would diminish it's properties and affect the end product.
Was it reacted long enough at 55C (130F) to assure a complete reaction ?
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I am not absolutely sure it is water. I did a water test the other day, on the oil I used to make the small batch and it read at 5.3 psi which is .053% water content?? I think. I am not sure on all aspects of water in oil and what is acceptable, this is somewhat new to me. The reason I first though it was water is that the fuel was cloudy for like 40hrs and then it cleared up and this is when I noticed that there was a layer of sorts on the glycerin, this layer looks like it indents into the glycerin, almost like craters on the moon. Today I will try and reheat the fuel as maybe, as you mentioned, I did not keep the oil hot enough long enough. I did originally bring the oil to 130 degrees but when I added the hydroxide it was probably down to 125, perhaps this is the problem?
As for the NaOH, we had an issue with mice in the building, we also store our sunflower seeds at the same place, sorta, so I opened the bags we had left and poured them into new 5 gal buckets then sealed them with a hammer and all....do you think that this NaOH could be bad?? We had a back that got chewed open by mice, when I realized it I poured this one into a bucket of it's own, this one did have a few 'clumps' but they were not hard and easily broken up. Any thoughts here?? Also do you think if we held onto the bags for a few months that the bag itself is good enough to preserve the NaOH?
Thanks for your help!!
Sodium hydroxide and potassium hydroxide react with carbon dioxide in the air. I keep a tight lid on my potassium hydroxide. You say you added your hydroxide to the warm oil at about 130 degrees farenheit? Do you mean you added the caustic dissolved in methanol, or you added the sodium hydroxide as a solid to the warm oil?
Yes I certainly dissolved the NaOH in Methanol, made sure it was all dissolved then added it to the oil. I reheated my batch I had made, that looked like it had the water layer and it now looks perfect!
I do have an issue with my 'old' oil, which is NOT used for frying, I press oil seeds then clean the oil and make fuel out of that, so when I say 'old' oil I mean I am trying to work with oil I pressed and harvested in the Fall of 2012 so it sat around in a 250 gal tote, inside for a few months. I have tried titrating this oil numerous times but every time I get a titration of 4.0-4.5 which is really high, I continue on to make a small batch of fuel but it completely gels up once it cools down a little. This is where I am having most of my issues. I really want to use up this oil as I have a lot of it but I don't know how to get it to react properly. I did do a water test on this oil as well and came up with 7.4 psi or .074% or 740 PPM . Is this oil too wet? Should I heat the oil to remove the water? We have a large vat which I can heat up the oil in and has an open top so water could evaporate here? I am thinking of trying this process then titrating the old oil again.
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