Boil kettle with a hot oil jacket?

Hi

I'm building an electric fired 55 gal system of used SS tea tree oil drums.

I'm considering to put the heating elements below the bottom of the boil kettle in a sealed jacket filled with thermal oil. One of the benefits of this is cleaning would be a lot easier, and i could have a perfect whirlpool.

I would like to hear your comments on this, and experience if any.

Thanks.

Lars

Oil jacket makes sense to me, but I'm no engineer.

You know that tea tree oil can be toxic if taken internally, right? Clean those drums well.

I wouldn't seal the jacket, all fluids expand/contract even engineered themal oils. If you use the following oil expect 10% expansion at boiling, assuming 50F is the lowest the unit will see while in storage:
(212-50) x .0564 = 9.1368%
http://www.heat-transfer-fluid.com/heat-transfer-fluid/duratherm-450

The concept intrigues me, please keep us updated. I'd like to follow your build. What's your source on the SS drums?

Thanks to TimpanogosSlim for the advice to clean them well.

Last year I bought a rotating tank washer. I'm planning to wash (CIP) them with 80 C (176 F) 5% caustic solution in one hour, and a cold wash with 2% peracetic acid solution in 20 minutes and finally a clean water rinse.

I'll then boil 50 lites of water, and then boil another 50 liters. If it the smell of tea tree oil, I'll start all over.

Any comment are welcome.

Thanks to outside92129 for the comment on the oil, and it's expansion and the tip of the special oil, which i'll check out.

I'm in Copenhagen, Denmark and got the drums at a hardware store selling them for $50 a piece, pretty cheap i must say. SS and brewing gear is extremely expensive in DK. US prices is aprox. 1/3 of DK prices. So normally when ever friends or familly travels to the US they carry loads of stuff home to me

I friend just carried a Blichmann 55 gal false bottom home to me, and the next i need is the strainer from BrewersHardware.com for the boiler.

I'll keep you updated.

Thanks.

i remember the same question on the other website and answer that made a lot of sense to me was that it would be very inefficient method (sorry i dont remember explanation right now) and that steam jackets BK are so popular because they are something about 4 times more efficient in heating

Steam could be very nice, but very expensive.

Releasing 240 cal pr gram (1/1000 kg) in going from steam to liquid is a lot of energi and only at 134 Celcious.

Could be nice for me, but not for my my wallet.

IMHO if the outer layer were also insulated most of the energy would go into the wort, so it'll still be much more efficient than propane.

A thought to solve the thermal expansion problem: install a relief valve that relieves to an expansion tank (aka an over flow tank). That way you maintain a solid layer of oil while minimizing over pressure and possible rupture of the drum. Im not sure what size or pressure rating you would want the valve, but it should work.
A nice insulation jacket around the outside of the oil drum should also ensure the majority of thermal energy goes into the wort.
Another idea, complete tangent... Build an immersion heater with oil circulating through it. As long as you pressure test and use a solid chunk of Cu, there shouldn't be a problem (other than cleaning, but you will get a more complete thermal transfer with the coil heater).

IMHO way to much work and risk of personal injury (not to mention risk to your home) for the small savings in propane

If you don't plan to push the temperature too hard, consider using propylene glycol in the jacket. It is relatively cheap, non-toxic (food safe), and low vapor pressure.

Lazarous said:

IMHO way to much work and risk of personal injury (not to mention risk to your home) for the small savings in propane

Click to expand...

Have you seen the price of propane in DK lately?

bendiy said:

Have you seen the price of propane in DK lately?

Click to expand...

No I have not, but I have seen what happens when a liquid filled container is heated to the point of bursting. IMO when it comes to safety it's worth it to spend the extra money. With projects like this if you don't know exactly what you are doing its better to hire a professional

Thank you for all your comments.

At the present time, I haven't decided whether I'm going the hot oil way or what. I'll keep you informed. It's kind of unknown territory.

For those who care I can inform that propane for a 42 gal batch will cost around $50, all included. ;-)

Lars