I've learned a lot on this site and want to thank you all for the insight and tips. I started with UCO, titrated instantly so I used 3.5g NaOH/l and did the mason jar version of the Dr. Pepper process. Worked fine. Moving onto WVO... nothing but gloop to date. The oil I have titrates at 10 NaOH. I have read that KOH works better with high percent FFA so I moved onto the two stage process where my first sample dropped to a 3.0... continued with the base phase using 6.5 g NaOH/l and again gloop!

Question is... can NaOH do the job or does it have to be KOH?

I think my titrations, measurments, temperatures etc are pretty good but my one weakness at this point is the mixing of methoxide and WCO. I am using a mason jar so I have remove jar from heated water bath, mix, return to bath and put the stirring rod in and turn motor on. The motor does not turn fast enough to create any visible vortex.

Any thoughts or comments would be appreciated.

Thanks, Greg

mac48,
with oil this bad it needs different processing or preparation before processing.
first choice -> acid/base processing. read all you can about it.
second choice -> using baking soda and water mixed together then mixed with the oil. -> there are many post on how to do this.

on you current mixing setup, you might be loosing methanol when you remix.if this is Dr.Pepper size batch just shake the container.

-dkenny

Mac,

Make sure that your titration measurement corresponds to your Lye.

Example: Lets assume you use KOH 90% pure and your oil titrates at 10. In this case you will mix 3 grams of KOH lye into 3 liters of distilled water for your lye solution.

If you are going to consider switching to NaOH, make sure that you make your lye water batch out of 3 grams of your NaOH in 3 liters of distilled water.

If you titrated at 10 for KOH (purity 90%), then the titration value for NaOH (purity 95%) may give you a different value.

Does that make sense?

dkenny,
sorry I wasn't clear, I did use the acid/base process. The acid step is where my titration dropped from 10 to 3 NaOH. I then performed the base step using 3.5 + 3.0 for 6.5g NaOH/l. I think your comment about "oil this bad" is very helpful. If the required catalyst is 3.5 and 7.0 g/l for NaOH and KOH respectfully, then my oil would titrate at 20 using KOH! I have KOH on order and I will seek out additional samples from other sources.

OOPS, I just did the math and found only a 40% difference in the normality of 1g of NaOH and KOH in 1 litre of H2O so I think oil that titrates at 10 NaOH would titrate at approx 14 KOH. This also means that if 7g/l KOH is correct, then 3.5g/l NaOH is low and should be about 5.0

PwrStrk,
I am using NaOH now and with little success wonder if KOH is the way to go. Your 3 grams KOH in 3 litres of water is a good way to increase accuracy of titration.

Anyone having luck using NaOH on high FFA oil?

Thanks

I still screwed up the base step somehow but at least I got a quality acid process where the WVO originally titrated at 16 (KOH) and ended up with 2.6 after 16 hrs.

By the way, I did a titration using both KOH and NaOH and found that the KOH number is 1.4*NaOH number/KOH purity.

Hopefully I get another good acid process and will re-attempt base stage. I'm doing this in a mason jar so what do you think of mixing methoxide and oil at room temp, shaking manually for 15-20 minutes and then heating to 60C without mixing?

Thanks,
Greg

mac48,
yep the difference between KOH and NaOH is 1.4..

first if you stay with NaOH you're not using enough for the base number it should be 5 not 3.5. 3.5 is what was used a couple of year ago. for KOH your 8 or 8.5 for the base

as for processing in mason jar..don't know. I do know the acid stage can and does work ( takes longer) if its just sitting. it might be better if you heated the oil to 60C first then added the methanol/acid...shake then let it sit..just a speculation. the smallest acid batch that I've done was 55 gallons..yep a full batch..

please keep us post on the results.

-dkenny

Dkenny; your right on with the acid stage working well with little or no heat and stirring. My last sample measured 15.5 KOH. I mixed the meth and acid and added to room temp oil (dried and filtered), shook well for 5-10 minutes and placed in a water bath at 40C for about 36 hrs. The oil then titrated at 2.5 KOH.

The reason I went to a lower temp and no stir rod is I had discovered that I was losing as much volume during the acid step as the meth I had added. This of course explains the last "jar-o-gel" I made last base step.

So I get home this evening all primed for what I know is going to be a huge success and as I'm getting everything ready.... I knock my 2.5 jar of oil off of the table which then smashed on the concrete floor! Ugggghh! Oh well.. back to one.

Thanks again for the input and I will report back in a few days.

mac48,

sometimes things happen...don't ask the number of times I've washed my shed floor with water and BD...if you're curious BD and water makes a great floor clearer. even if its a wood floor.



-dkenny

dkenny

I do believe I have found the problemo. Each previous attempt of acid/base processing had little time (1/2 day) between acid and base steps. Each attempt went hideously wrong in one manner or another. Anyhow because of work and weather, the latest attempt sat for about a day and a half after acid. It was cold when I went out this am and noticed that there were two distinct precipitated layers. The bottom most maybe maybe 20-30 ml (total sample 575 ml) and the second which seemed to be particulate matter about 50 ml. Original oil titrated at 16 KOH.

Question is... how do you filter your WVO. I don't think I'm doing a good job of it.

Thanks as always.

mac48,
I only filter my oil through a window screen. so I too end up with junk the glycerin layer.

-dkenny

I do believe there's biodiesel in that there mason jar. I siphoned off a sample from the previous post after acid catalysis, titrated 2.6 and reacted with appropriate meth and KOH, processed and allowed to stand over night. There was a perfect 80/20 separation but I was surprised at how dark the bd was. I proceeded to the wash test where I put a small sample in jar followed by same amount water, I swirled for 5-10 seconds. The two separated within moments and now the bd was much lighter in color. I then screwed the lid on and shook, the bd and water again separated very quickly but this time the bd was cloudy. I then put 27ml meth in a small jar and added 3ml unwashed bd and mixed. The solution was light yellow and appears as the bd was completely dissolved. After nine hrs the solution is same color and no discernable precipitant. What do you think?

Thanks,
Greg

sounds great to me.
you made biodiesel

the wash test really doesn't tell you much until the fuel is well washed. then it'll give a crude indication of the soap content.

the 27/3 is a much better test. sometimes I'll try putting in more BD. upwards of 7mls. some batches it'll dissolve and sometimes they won't. as along as they pass 3mls I'm happy.

-dkenny

Cool beans man. I'm now looking for oil sources and trying to decide on a reactor design.

Thanks again for the help and I'm sure I'll be back for more help in the future.

Greg