Sciencemadness Discussion Board

Which liquide for a recirculator heating bath

Lefaucheux10 - 12-2-2017 at 02:39

Hi everybody,

I recently buy an old Lauda heating recirculator bath and i have a double wall 1,5L glass reactor

( http://www.used-line.com/PicturesAuto/623/10616623.jpg )


the problem is the bath can go at over 350°C and using water in the bath not permit the reactor to reach more than 90°C

The question is what is better ?

the bath is 5L one

I have choice of thir 3 products what is the best ?

https://www.mon-droguiste.com/huile-de-paraffine-industriell...

44.15 €

https://www.mon-droguiste.com/huile-de-vaseline-clarifiee,fr...

37.05€

https://www.mon-droguiste.com/monopropylene-glycol,fr,4,PROG...

55.80€

scuse my poor english,


Thanks for your answers




Sulaiman - 12-2-2017 at 03:32

Boiling points;
287C, Paraffin oil
188C, Monopropylene Glycol
68C, Clarified vaseline oil

other options:
https://en.wikipedia.org/wiki/Cooking_oil

unionised - 12-2-2017 at 05:47

Quote: Originally posted by Sulaiman  
Boiling points;
287C, Paraffin oil
188C, Monopropylene Glycol
68C, Clarified vaseline oil

other options:
https://en.wikipedia.org/wiki/Cooking_oil


Cooking oil is a good option; so are some silicone oils (at much higher cost).
Can i ask you to check on "68C, Clarified vaseline oil"?

Sulaiman - 12-2-2017 at 06:42

I took the 68C from the link in the OP
but further research yields 'better' results
e.g. 302oC http://www.inchem.org/documents/icsc/icsc/eics1440.htm

there may be a problem with the viscosity of vaseline at room temperature .. blocking pipes, pump etc. ?

BromicAcid - 12-2-2017 at 13:46

Don't just go by boiling point. Take note of autoignition temperatures if you're going anywhere near 350C. Also note smoke points if you are thinking about using oils. We have a high-temperature recirculating bath that we use at work for 175C or so and because it is not a sealed system we cannot go higher than that because of the oxidation that will occur to the thermal fluid at those temperatures. If you're expecting anything more than one time use at those temperatures I would recommend an engineered thermal fluid.

Find the manual and look it over closely, the manufacturer may recommend certain thermal fluids. You might want to stick with those for seal/gasket compatibility. Also, where is the 350C figure coming from? Is this just from the dial on the unit or does the literature say that it will get this hot? It just seems a bit excessive for a unit like this, if it is just something on the dial I would wager that while you are circulating and putting a load on the system it won't get near that actual value.