Propylene Glycol

[SMD]

Hi,

I'm looking into a high temperature application for my Woodgun E250. I want to fill the boiler with about 80/20 propylene glycol to water mix. Then run it at 300F, circulating the hot glycol through pans to boil water. (Maple sap for a maple syrup operation.)

Does anyone have experience running proplyene glycol in their boiler at high temperature?

Thanks,

Andrew

 

[peakbagger]

I have looked at it for industrial applications. If you go over 250 deg F you need the acid inhibited variety.
(broken link removed to https://www.dynalene.com/wp-content/uploads/2018/09/Dynalene_PG_Technical_Data_sheet.pdf)

If you overheat it if gets very acidic very quickly.

 

[SMD]

Thanks, that's excellent information. Is the high limit 300F?

 

[peakbagger]

Looks to me to be 350 F. There are some exotic heat transfer fluids that will go higher.

 

[NateB]

What if you used your Woodgun to get the temp up to 180 - 190 with water, and a fuel and burner to do the rest? Putting a poisons liquid through a pipe that is in a edible liquid would make me very nervous. What would be cool is a wood gas burner.

 

[maple1]

I guess I will say it in this thread too. I am about 95% sure doing something like this will lead to disappointment of some sort. And now talking about glycol in such close contact with a food product is extra bad mojo.

 

[peakbagger]

Polypropylene Glycol is relatively safe compared Ethylene glycol. Its used as food additive and any one that ever have colonoscopy had to chug down a gallon of it. Not sure on the toxicity of the inhibitors.

 

[maple1]

Dont think I'd want it any where near my maple.

 

[S.Whiplash]

What if you used your Woodgun to get the temp up to 180 - 190 with water, and a fuel and burner to do the rest? Putting a poisons liquid through a pipe that is in a edible liquid would make me very nervous. What would be cool is a wood gas burner.

This is a better method IMO, it uses the wood boiler within the constraints of it's design and does not void the warranty. I have seen a Polar G-3 used in conjunction with a NG boiler to purify honey in this way and the whole operation works very well and does not contravene safety standards in any way.

 

[SMD]

Propylene glycol is edible. Really, though, if the glycol is getting into the syrup, that means a ruptured heat exchanger, and I have problems way beyond glycol in my syrup!

Thanks all for the input, very helpful.

 

[maple1]

This is a better method IMO, it uses the wood boiler within the constraints of it's design and does not void the warranty. I have seen a Polar G-3 used in conjunction with a NG boiler to purify honey in this way and the whole operation works very well and does not contravene safety standards in any way.

Making maple syrup takes waaay more energy than purifying honey. Huge amounts more. Which is why this whole thing IMO would end in disappointment.

 

[NateB]

Chances are your HX will not rupture, but will get a pin hole leak, and will mix in to your maple syrup slowly. By the time you figure out it is leaking, how many gallons have you processed? I know the government says its ok to eat, but I would not want it in my syrup, and are you will to list it as an ingredient on the label when you have a leak?

 

[maple1]

Propylene glycol is edible. Really, though, if the glycol is getting into the syrup, that means a ruptured heat exchanger, and I have problems way beyond glycol in my syrup!

Thanks all for the input, very helpful.

If maple syrup gets to the public with anything like that in it, you would have problems way beyond a leaky HX.

 

[SMD]

I couldn't agree more on comments on glycol in syrup. Absolutely unacceptable.

This is a research project, and the conclusion may very well be that it's a bad idea.

Again, thanks all for you input!