Is there someone who knows a manner to reduce the free fatty acids of oil (6% FFA to 1,5-2 % FFA)but the triglyceride of the oil may not been changed. The oil will be used ass fuel

Is this possible?

talking out my back-side... but

couldn't you cool the oil until the ffa solidifies then decant the still liquid non ffa oil off.

haven't researched or thought about it before... but seems like one possible solution.

I will try

I believe you can wash out FFAs with methanol by adding 20% methanol, mixing well, allow the oil and methanol to separate and draining off the methanol. If you want to eliminate all the FFAs it might take multiple washes. You could acid process the FFAs washed out of the oil separately to increase your yield.

supposedly you can also reduce FFA and also remove some fats by mixing the waste oil with glycerine byproduct from biodiesel production and then letting everything settle.

Mark

What exactly are you refering to as FFA's? Are your Percentage numbers derived from doing a biodiesel titration test ? Are you refering to diglycerides and monoglycerides, or do you mean high meltpoint oils like tallow and hydrogenated oil, or possibly water soluable acids ? There have been discussions concerning the definition of FFA's, apparently high meltpoint fats and hydrogenated oil do not nescicarrily qualify as FFA"s

Do you want to save the FFA's or dispose of them. the glycerin mix will end up with the glycerin in the FFA (tallow and fats) so it is pretty well lost, same with using lye to make soap out of them and then draw off the remaining unreacted oil(there are discussions here about both methods, try the "find" button).

I do a water wash with baking soda to neutrilize the water soluable acids.

I am just now starting to build a refrigerated 25 gallon tank device to seperate clean dewatered warm filtered oil into high and low meltpoint oils. I intend to use the higher meltpoint stuff (hydrogenated oil and animal fats) in a heated vehicle tank and use the low meltpoint oil for blending. I will post a discussion on this once I get it built and do testing.

I use BS also. It is soposed to reduce ffas. Mostly it makes my oil nice and thing which is good since I dont heat my tank. Can anyone educate me ass to the dangers of FFAs??
Erik

glycerolis: which proportions(glycerol/oil) do you use?

the engines we use are resistant against 2% free fatty acids.

BTW: freezing doesn't work 6 %FFA --> 5,8 %FFA

Can you explain the "freezing doesn't work" statment, you can't simply freeze the oil, you need to pick a temp where you want to seperate the oils so some oil stays liquid and some turns solid, I will be shooting for 40 deg f. You will have to wait for whatever time it takes for the complete tank of oil to stabilize at that temp and then wait for another few days for the high melt point stuff to solidify out of the oil and drop to the bottom of the tank.

Here are a couple discussions I found by using the "find" button at the top of the page.

lye stripping

Reducing ffa discussion from 2004.

A hot water/NaOH wash is what is used commercially where the FFA and some feedstock is converted to soap-stock which settles out....

Treatment of the soap-stock with H2SO4 will recover the FFA for further treatment....

The oil from the first-stage will then need to be dried before use....

The FFA recovered from the second-stage, could be Acid-Esterified to make BioDiesel for your twin-tank system.....

Freezing will only remove high melting point fats. It wont effect FFA which are Free Fatty Acids which are carbon chains that have broken off the glycerine in the triglyceride molecule. They are acidic but not high melting point.

For some reason there is a long standing widespread confusion between FFA and high melting point fats such as animal fats. They are not actually related.

OK - Good info - I thought I had read something about high meltpoint stuff not actually relating to FFa.

Apparently then the only way to reduce actual FFA's HAS TO BE some sort of chemical process, either acid or soponification ?

what about water bubble washing to remove the acids?

not water soluble.

Mark

quote:

Originally posted by erikk:
Can anyone educate me ass to the dangers of FFAs??
Erik

According to various industry sources, there was research done which showed that FFA in biodiesel (not in WVO) can sometimes cause some kind of gummy deposit to form.

I don't know of a Web link to this, it's probably not posted anywhere, but you can ask Steve Howell of the NBB if you're really interested, he's one of the people who told me that these studies were done in the early days of biodiesel research in the USA.

Mark

I don't think it is because of high FFA's but I sure have a lot of gummy deposits all over everything associated with my WVO.

(sorry, just could not pass that up. Hope it does not confuse the issue any more than it already is.)

that would be polymerisation at work...

Does polymerization require heat.. high heat? I noticed some gumminess around my fuel tank filler neck area.
Rich

just kidding. Yes, when WVO 'dries', it's technically polymerisation. I think it'll happen even without heat, unless you count a hot summer sun beating on a restaurant grease barrel as 'heat'.

Mark

http://64.233.183.104/search?q=cache:8woATC3MKqwJ:www.n...=10&client=firefox-a

discussion of ffa removal. p32 says ethanol is good to remove ffa but doesnt say how - perhaps just mix and settle as dave_d says to do with methanol. Only difference is that with ethanol you wouldnt have to bother with washing out the ethanol contamination.
Furfurol looks interesting too - it says it seperates liquid and solid fats but, again, no method - wash and settle?.