Report on Oxidation and Polymerization of Vegetable Oil

[fgregg]

I'm very pleased to finally release Joe Beatty's report on the oxidation and polymerization of vegetable oil. Mr. Beatty, known on this forum as grzpdlr, has worked his whole life in the vegetable oil business, and this report represents a very generous sharing of his expertise, along with a considerable expenditure of time, effort, and expense.

Mr. Beatty's original research should be troubling to everybody in this field. Work continues to bring the antioxidant and metal inhibitors mentioned in report to market, but right now there is no solution to oxidation and polymerization of vegetable oil, although Mr. Beatty discusses many ways we can mitigate these processes.

-Forest

[corrected version uploaded Jan 2, 2006. Corrections: typographical error; SVO Supply was misidentified as a contributors of test samples, it was Fpmbstca.]

[RNCarl]

Simply outstanding!

Much better than all the chest beating and finger wagging!!!

Questions and comments.

1. Would a bladder tank similar to a racing fuel cell help with the sloshing and decrease the air exposure?

2. The antioxidants. Do they increase pollution when burned? i.e. in the fuel.

3. What about polymer tanks? Interfaced with stainless parts?

Now I know why my conversations with the local chem profs here got me patted on my head and sent on my way. I don't have access to any of the equipment used in this testing. Nor, frankly, is my 2 semesters of chemistry sufficient.

Thanks!

C.


.

[phil]

Interesting, and I am always appreciative of research. But it makes it sound like driving a car with a half filled veggie tank is a death sentance.

This has not been my experience; I'm guessing it is a case where it appears much worse in the laboratory. Nevertheless, I would be interested in those additives.

I also noticed the suggestion about looping the fuel return. I've always done this and find it works well for many reasons.

[siebertluke]

Wow, lots of stuff there. Can someone put it into laymens terms for me? How does this effect the way we de-water w/ the frybrid still? Is this still recomended? What about heating to get through filters on the still?

[cgoodwin]

Don't misunderstand the research. If you examine the results they will likely be very close to what we all experience, heat and exposure to reactive metals speed polymerization, this is why everyone experiences more frequent filter changes in the summer, the ambient temp is higher throughout the day speeding the process. Even if you have a copper coil in your tank the process would take 12 hours continuous heating the raise peroxide values to 50 mEq/l. If you have a 15 gallon tank and drive for 12 hours at highway speed you would have to get better than 48 mpg for the fuel to reach this point.

It should be viewed as a guideline for system design, avoid reactive metals, do not insulate the tank so it cools quickly, heat the oil being drawn from the tank rather than attempting to heat the entire tank, have a tank with baffles to avoid agitation, limit heated fuel returning to the tank or return it where it will be drawn up and used. These are many of the design parameters we use in the Frybird system and if you aim for a design which minimizes thee processes, you will be ahead of the game.

We have drained many gallons of polymerized fuel from vehicles, often those which have been stored for some time with VO in the tank or vehicles which had been driven for some time without using the VO in the tank. Polymerized fuel still seems to produce good biodiesel and even properly made biodiesel will go through this exact same route to polymerization. Modern fuels and oils have chelating agents and antioxidants added to stabilize them, there is currently work being done toward producing such an additive for VO.

[Pir8Darryl]

Chris, and others in the know...
If I read that correctly, exposure to air and the presence of a reactive metal facilitate the poly and ox process. [or at least speed it up]

Any benefit to powder coating the inside of the tank?

Any benefit to flushing the VO tank every so often? If so, with what?

How does stainless steel stack up against alum, copper, mild steel?

[cgoodwin]

Aluminum seems to be the least reactive common metal, there are other factors to consider as well, like the evidence that polymers can only bond to steel..

You want to limit exposure to 02 and to reactive metals and limit heat, the only practical way to limit o2 exposure is to keep the fuel from sloshing about as much as possible, limit exposure to reactive metals and use the fuel in your tank. If you have a 100 gallon tank and only use 15 gallons a week, maybe a smaller tank would be an idea.

[JeffNLisa]

Grzpdlr:
THANK YOU THANK YOU THANK YOU for everything that yoy put into that report.



Chris,

Originally Posted by Pir8Darryl

Any benefit to flushing the VO tank every so often? If so, with what?

If you have input on this one specifically I would like to know also.

Seperately, it's been about a year since I remember reading something you said that I haven't been able to find again and I've looked. It seems you suggested that BioD would also lead to crankcase polymerization, if used as a startup fuel, because of excessive blow-by when the engine is cold. In this thread you have confirmed your feeling that BioD does indeed polymerize under the correct conditions.

Do you think (or are you aware of any more specific info supporting) that BioD as a startup fuel will lead to this problem?

Thank you.

Jeff



AND THANK YOU THANK YOU for everything that Frybrid put into that report. You and Forest both.

Jeff

[dana linscott]

More research needs to be done as to acceptable levels of
water in fuel. Toward this end the Karl Fisher unit used in this
study can be made available if someone would wish to pursue this
further.

Indeed!
In fact I believe I know of someone who would be very interested in continuing this research. How do they arrange for use of this unit?

I see several conclusions I believe could be sucessfully challenged and a few omissions which appear to slant the conclusoions significantly.

I am not sure if it is permissible to submit challenges or critiques however.
Please let me know if it is.

[phil]

I would think that keeping the tank full should also help. Perhaps top it off every evening?

And JeffnLisa has a very good question about polymerization of biodiesel. Does anyone know the answer?