7 replies to this topic

[Sadananda Konchady]

I am looking for the value of the volumetric coefficient of expansion of ethanol at 65 deg C. Does NIST or other sources have this information?   Perry's Handbook indicates the density of ethanol up to 40 deg C.

 

Thanks,

[PingPong]

http://ddbonline.ddb...mponent=Ethanol

[MrShorty]

PingPong's link shows how to calculate density using DIPPR's variation of the Rackett equation for ethanol. From NIST's website (http://webbook.nist....hemistry/fluid/ ) you can calculate densities for ethanol using their EOS. From those densities and your definition of volumetric expansion coefficient, you should be able to calculate the desired coefficient.

[breizh]

http://www.ddbst.com...PCP/DEN_C11.php

Consider this table .

Breizh

[Sadananda Konchady]

Thank you very much Breizh, Mr. Shorty, and PingPong for your information on ethanol.

[katmar]

Disclaimer: I am the author of the computer program AlcoDens which is aimed specifically at ethanol density calculations and I may not be as objective as the other posters.

 

The results given by the DDBST correlations differ fairly significantly from the Perry data for temperatures below 40°C.  The Perry data originates from the same sources that were used in the generation of the alcoholometric tables that are used in the beverage industry.  These tables have been used for around 100 years and have stood the test of time.  Even though the DDBST data are newer I would use them with caution because of the differences from Perry.  The graph on the DDBST web page shows a fair degree of scatter, which adds to my nervousness.

 

Note also that the experimental data reported by DDBST (see breizh's post) include high pressure data.  Liquid ethanol is somewhat compressible and the pressure should be taken into account in calculating the expansion coefficients.

 

In calculating thermal expansion coefficients you will be more interested in the changes in density with temperature than in the absolute densities themselves, so perhaps the discrepancies are not too bad.  It depends on the accuracy you need for your particular application.  Using the AlcoDens data I would estimate the thermal expansion coefficient at 65°C to be 0.00126 m³/m³.°C and using the DDBST data it would be about 10% higher.

[Sadananda Konchady]

Thanks Katmar for your feedback.  I tried to estimate the value for volumetric thermal expansion coefficient at 65 deg C from the DDBST data and it seems to be 0.00128 m3/m2.deg.C based on the experimental density values at 59.85 deg C and 76.85 deg C.  It is indeed close to your answer.

 

Regards

 

Sadananda Konchady

[P.K.Rao]

Reference: 

http://ddbonline.ddb...mponent=Ethanol

 

Please visit the above web page