Monday, July 7, 2008

Q&A: Vegetable Oil Storage

I recently received the following questions from Scott via email:
I am thinking of going with a WVO system in my 2000 Jetta TDI. I would like to know what kind of storage container (metal or plastic) I should get? Is one better than the other?

Also, I live in an area that gets very hot and humid in the summer. Should this be a concern?

What should I do for long term storage of filtered and de-watered WVO?

I have also been told that burning WVO (filtered and de-watered) causes Sulfuric Acid to be created and that will damage the valve train and exhaust system. Is this true? How can it be prevented? Thank you very much.

Best regards,
Scott H.
Hi Scott,

Thanks for your message!

As far as storage goes, I always used the standard 4.5 gallon plastic "cubies" that restaurants purchase their oil in. They're light weight, (usually) free, and recyclable.

The downside is that they aren't as strong as other storage containers. I never had a problem, but I was always careful to store them on a cloth tarp instead of bare concrete (to prevent punctures), and I never stacked them.

Despite my personal practice, I really like Lovecraft Biofuels' home fueling station/storage container (they don't seem to have them in stock at the moment). It's just a barrel, wheels (for the barrel), a hand pump, and a sock filter (link). You could probably remake one of these with parts from Harbor Freight and McMaster for pretty cheap.

Hot and Humid Climate: While I owned Minnie, we traveled through many hot and humid environments (including a swamp), and I didn't have many issues. My advice is pretty standard: keep your fuel in a dark place, keep a lid on your fuel, remove fuel from the top or middle, never the bottom (that's where water settles!), if you're worried or if you see stuff growing in your fuel, use a biocide in the summer to treat your fuel (ask your local diesel mechanic or farmer's supply).

Sulfuric Acid: I wonder where you heard that rumor about sulfuric acid coming from veggie oil because there is zero sulfur in vegetable oil, so no sulfuric acid can possibly be produced when it is burned.

On the other hand, petroleum does contain sulfur, so sulfur oxides are produced when you burn petroleum diesel. When those sulfur oxides react with atmospheric water, sulfuric acid and acid rain are formed. Notice that none of that acid is formed in your valve train or exhaust system. Note: in 2007, new ultra-low sulfur fuel was introduced in the US, but there is still some sulfur present in all petroleum diesel fuel.

There are (of course) other issues with burning veggie oil, but sulfur isn't one of them. Religiously change your engine oil every 3,000 miles and give your engine a few doses of diesel purge every once in a while and you'll probably be fine.

I hope this helps, and good luck with converting that Jetta!

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