In my ever ending quest to figure what to do with raw biodiesel byproduct, I have been toying with acidification (just a gatorade bottle and a randon spash of HCL s far). I got a glycerin layer on the bottom and a really dark (and thin/much more liquid )till it gets cool at night)) layer of what I think is hopefully pretty pure FFA on top.
Was wondering if anyone has figured out something good to do with this really dark FFA layer. I think it is ~ 1/3 of the total volume of the starting byproduct.
The glycerin is a lot lighter (still a dark murky orange you - about about the same color as some "average" WVO). I assume any extra acid i may have added is in the glycerin (not the FFA). Am I correct here?
Ideas and experiences would be appreciated.
Thanks in advance.
Have you tried Acid Esterification?
Here are some notes about some tests... I kind of got lost in the middle.
But, as far as I can tell, it requires A LOT OF METHANOL.
I.E. Perhaps an equal amount of Methanol and FFA (or more). Which, of course, you would recover in a later step.
Thanks for the read Keelec. Sounds like AE of pretty much pire/very high percentage FFA might not be practical. I did finally get hold of a batch of really bad oil (preliminary trtration amples range from 20-30 NaOH). So I am going to see how AE goes for me on that.
But maybe, if that goes well and doesn't show to add too much cost/trouble, I can (alway, as a part of my batch process) acidify the byproduct. I do a WBD (whole batch demeth) first so the methanol is "mostly gone I think". Then add the FFA to the next batch and just do some AE as part of the normal process for every batch (even for fairly good starting oil..
Wonder how much that will drive up cost. I am going to get 4 liters of sulfuric acid shipped in to start on this bad oil.
But then.. I think I have that watery acidy methnol black stuff you have to drain after AE that I have read about....(shhesh)
I'm not sure...
You probably don't want to add MORE FFA's to a batch of clean oil, although I was wondering if one could do the Acid Esterification... then use that as part of the methanol for the next batch.
Water content, of course, would be an issue, especially considering that Acid+Base ==> Water + Salt.
Many people add acid as an intial step. See the films by Graydon & Utah Biodiesel.
I have run the split FFA mixed 50/50 with biodiesel in my vehicle with no issues. I believe it is a bit more corrosive than straight bio or dino diesel. the key is making sure that you get all of the salt out of the FFA, which can be a real PITA. I used centrifuges for this and it took a long time. You can also water wash it and cold filter down to 5 microns or less.
my ffa layer titrated at about 20 KOH, and the specific gravity was very close to that of biodiesel. I can't remember exactly what it was right now, but I know it was close.
the WVO users are already burning FFA successfully in their vehicles (plus glycerin) so I figured it was low risk.
do you routinely crack the glycerin and get 20KOH oil from the top layer?
I'm asking..I know its been a while since you posted..but 20 KOH is easy to process with AE..
I'm wondering if I should figure out the acidulation of glycerin and reclaim the FFA's. Then I would just take the FFA mix with incoming oil..titrate and process as needed.
'84 bluebird school bus, DD8.2L turbo( 4/2011, the bus tranny has died.. 8.23.11 bus driven to scrap yard )
2006 Jeep Liberty CRD - the wife's
99 dodge 2500 5.9l 24v..-mine
everything run B100 when its warm enough
Yes, that is correct. 20KOH titration from the FFA layer after cracking the by-product with sulfuric acid.
You can indeed use the FFA as additional feedstock. I have done that too, I typically just mix the FFA 50/50 with the WVO and dewater/titrate/process. The key is making sure the FFA is clean enough to process. You really need to make sure that you get good separation, otherwise your FFA layer is polluted with salts. You can do a soap titration with bromophenol blue to figure out how much acid is need to completely nuetralize the FFA. I usually just take a few half liter samples, add different quantities of sulfuric and determine the winning amount. Typically 3%-5% by volume sulfuric.
I think of the ffa layer as free feedstock.
|Powered by Social Strata|