I originally posted in the Making Biodiesel section, but thought it may be more appropriate asked here.

After I processed my last batch and let sit overnight, I came back to find a light gray color oil all the way up my sight tube. There was only a little section at the top of the sight tube that looked like the BD usually does. I am not sure what has happened and I'm not sure what to do to save this batch or if it can be saved. Any ideas on what to try would be great

This is from a 140 liter batch, 28L methanol, titration originally 18, down to 4.5 after acid stage. I used KOH base of 7.5 plus 4.5. I used 17 liters methanol for the acid stage originally and then out of the 11 liters left for the base stage I used 5 liters in order to get my titration down to the 4.5 mark. This left me with roughly 6 liters to mix the KOH in. The methoxide was introduced very slowly because of the concentration, took about 30 minutes to get it all in. Processed for 2 hours at 130 degrees and let set overnight. Came back to find the light gray colored oil up most of the sight tube. I then added another 6 liters to the batch at 130 degrees and ran another 2 hours, settled overnight and same light gray color in the sight tube. When I go to drain some, it looks dark but not thick like glycerol and then turns to a lighter brown after only a few seconds. I'm not sure why the sight tube shows a darker color almost to the top of the fluid level, because like I mentioned above the oil comes out like looking like unreacted oil after just a little draining.
Again any help or direction on this would be great...thanks

keis779,

after the first acid stage did you try draining?
when you added the addition 5 liters of methanol did you add more acid? or just methanol?

by any chance did you try a 27/3 test while the stuff was mixed?

if the 27/3 fails just reprocess the batch using 50-75ml methanol and 2-2.5g KOH/liter

one last suggestion. instead of using the whole batch as a sample, just mix it up and drain out 500ml and reprocess that first. if you make several of these vary the amount of KOH from 1-3g in 0.5g increments. of course make sure to use the 27/3 test to test completion. separation alone isn't good enough.

-dkenny

I did try draining after the first acid stage, but I don't ever seem to get any water to drain until the second acid stage. And yes I did add acid with the 5 liters of methanol. I was then able to drain after that second stage.

No, i have not tried any 27/3 test yet, I didn't think I was at a point yet where that would show much. I am sure I would have fall out, but I guess if I have less than 3ml fallout then I do have some conversion?

I do like the small test batch idea, I didn't even think about that. I guess I will be trying that today.

Thanks dkenny

since you drained stuff out after the acid stage, you're short that much methanol for the base stage. so for the 2nd base stage add use the amount drained in methanol and 2g of KOH/Liter.

-dkenny

Thanks dkenny for your helpful comments. I think my problem turned out to be a wrong setting on my digital scale. I came back to do some re-processing and found my scale was in pounds. I assumed this was the problem and re-processed with the corrected difference, which was a considerable amount. Everything turned out great with the usual separation and successful passing of the 3/24 test. I guess this is what I get for getting in a hurry and not paying attention to the units I'm measuring in or the fact that I added way less than KOH than normal.

Whoops....I meant 3/27 not 3/24