Thermal expansion of glycol mixture

[dpenz]

I need the coefficient of thermal expansion for a 50% mixture of ethylene or propylene glycol in water from 20 to 95C. I have found values for 100% glycol (650 to 700E-6 per degree C), and water is about 200E-6. Would it be correct to average the values for 100% water and 100% glycol?

 

[prex]

See

http://www.mrc-eng.com/Downloads/Brine Properties.pdf

but please review also FAQ731-376 point 2!

prex

http://www.xcalcs.com

Online tools for structural design

 

[dpenz]

Prex,

Thank you. I did search on the Internet quite a bit but under "thermal expansion" and "glycol", and didn't think to try "brine".

I'm still missing something, though. Several sources list the volume coefficient of thermal expansion (Beta) for water at 20C as 0.000207 per degree C. Looking at the chart in your reference, for 0% concentration, the chart shows 0.055 per degree K.

Would you please help me reconcile these numbers? Thanks.

 

[MJCronin]

dpenz,

I suggest that you contact the people at DOW Chemical....

They supply a number of different grades of both ethylene and propylene glycol under the "DOWFROST and "DOWTHERM" brand names

Good luck

MJC

 

[jmw]

There you go, talking at cross purposes!
I spent a long time talking with a pharmaceutical engineer about controlling his brine concentration and i was doing well till i asked if it was a sodium chloride brine. He looked at me as if i was from another planet and patiently explained that it was monoethylene-glycol and water. Well, what else could it be?
Beware of all such euphemisms!

 

[quark]

Jmw!

I too might have reciprocated in the same way. But you didn't talk to me definitely. In our pharmaceutical companies we do use MEG (sometimes CaCl₂, but I don't know the origin)

As it is mostly used for chilling application, increase in concentration is not a problem. It gets diluted often because of mixing with cooling water (in Bulk API plants)

Regards,

 

[jmw]

OK, humour to one side, this site has some temperature density and temperature viscosity charts for various strengths of solution so i guess it shouldn't be too hard to figure out from the change in density wirth temperature the thermal expansion figures:

http://www.houghtonchemical.com/fluids/wintrex/