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ta5ari (Automotive) (OP)
9 Jun 08 5:37
I need information on gasoline vapour pressure at different temperature, in particular in the 20°C to 80°C range.
I only find data at 100°F and that is not enough for my calculation purposes.
Any suggestion where I can find detailed abacus?


 
dcasto (Chemical)
9 Jun 08 10:46
First, because by definition, the Ried Vapour Pressure stated in literature is ONLY at 100F.  


Second, gasoline is a mixture of hydrocarbons, so there is no fixed value of a TRUE VAPOUR PRESSURE (thats the name for a vapour pressure at differnt temperature).

I ran a simulation on a mixture and got the following:  For a 10 pis RVP, the true VP was 5.2 psia at 20 C and 33 psia at 80C.  This is an example only, you need to do your own bubble point flashes on your composition.
 
dgallup (Automotive)
9 Jun 08 11:17
Gasoline RVP varies by local statute, season & altitude.  You can buy different RVP test fuels for hot start testing, etc.  You might want to contact Chevron Phillips or other fuel suppliers for more details.
black2003cobra (Automotive)
11 Jun 08 21:43
Not sure this is useful to you.  From the Taylor brothers' book.  Isooctane is on the graph, but not gasoline.  I believe vapor pressure of gasoline is varied between summer and winter blends.
Helpful Member!  mbeychok (Chemical)
25 Jun 08 15:14
ta5ari:

As noted by dcasto, Reid Vapor Pressures (RVP) are always at 100 deg F. And as noted by dgallup, the RVP of a gasoline varies by season, region, altitude and local regulation.

The U.S. Environmental Protection Agency's publication "AP-42: Compilation of Air Pollution Emission Factors", Chapter 7, Table 7.1-2, publishes the True vapor pressures (in psia) at 40, 50, 60, 70, 80, 90 and 100 deg F for gasolines having Reid Vapor Pressures of 7, 7.8, 8.3, 10, 11.5, 13, 13.5 and 15.

That Table 7.1-2 is at: http://www.epa.gov/ttnchie1/ap42/ch07/final/c07s01.pdf

If your need for such data is for calculating vapor emissions from gasoline storage tanks, then the EPA also provides a software program called TANKS which can be downloaded at http://www.epa.gov/ttnchie1/software/tanks/#order

Milton Beychok
(Visit me at www.air-dispersion.com)
.

 

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