I was wondering if anyone had ever had any experience converting an old dairy holding tank into a biodiesel reactor.

These things are usually stainless steel with a mixing paddle and are sometimes jacketed.

Please advise.

-Water Boy.

The milk tanks I've seen are all horizontal and have undesirable corners where unreacted oil could be trapped.
Also, the tanks I saw did not have tight sealing lids.

Do you need to have tight sealing lids on the reactor?

My appleseed currently has 2 vent tubes that allow gasses to escape is why I am asking.

The horizontal nature of the tanks are weird for sure, but the agitator in it is desirable, don't you think?

quote:

Originally posted by H20 Boy:
Do you need to have tight sealing lids on the reactor?

My appleseed currently has 2 vent tubes that allow gasses to escape is why I am asking.

The horizontal nature of the tanks are weird for sure, but the agitator in it is desirable, don't you think?

If you don't want methanol vapors in your work space, YES.

quote:

Originally posted by H20 Boy:
Do you need to have tight sealing lids on the reactor?

My appleseed currently has 2 vent tubes that allow gasses to escape is why I am asking.

The horizontal nature of the tanks are weird for sure, but the agitator in it is desirable, don't you think?

I don't believe the agitator in a milk tank would have the aggressive characteristics required for biodiesel mixing. While that doesn't mean it couldn't be used to compliment a pump mixer, there are other issues involved such as the design of the agitator mechanical system. One little spark in the wrong place and your milk tank might go sub-orbital. In-tank type mixing devices require special seals to prevent any chance of becoming an ignition source.

I would strongly recommend against using a milk tank of that type. While I do recognize they are common and easy to come by, you'd be better off with a cheap 500 gallon propane tank like my MM500 plans use.

We've used a 2000 gallon horizontal dairy tank for a couple of years now in our facility and it works really well. It has a horizontal agitator and 50% jacketed wall for heating. That may be a different type of dairy tank than what you're thinking, but it was a dairy tank. I think that they're right, if you get a square dairy tank, you'd need really good agitation to keep from getting stagnation in the corners. Just my 2cents.

-Dave