How to calculate flash point of mixture?

Click For Summary
SUMMARY

The discussion centers on calculating the ideal ratio of 200 proof isopropyl alcohol (2-propanol) and an aliphatic hydrocarbon mixture to achieve a flash point of approximately 70ºF. The flash point of isopropyl alcohol is 53ºF, while the petroleum mixture has a flash point of 142ºF. A suggested approach involves adding water to the alcohol to raise its flash point and then combining this mixture with the petroleum. The solubility of the components is crucial, as a two-phase system may occur, affecting the overall flash point.

PREREQUISITES
  • Understanding of flash point and its significance in chemical mixtures
  • Basic knowledge of thermodynamics and phase behavior of mixtures
  • Familiarity with Material Safety Data Sheets (MSDS) for chemical properties
  • Knowledge of miscibility and its impact on chemical interactions
NEXT STEPS
  • Research the "Effect of Additives on the Flash Point of Flammable Liquid" for practical applications
  • Learn about the properties and behavior of higher alcohols in mixtures
  • Explore methods for calculating flash points of mixtures using thermodynamic principles
  • Investigate the implications of two-phase systems in chemical mixtures
USEFUL FOR

Chemists, chemical engineers, safety professionals, and anyone involved in formulating flammable liquid mixtures.

JGAN
Messages
1
Reaction score
0
Hey guys,
I would like to create a mixture out of two liquids with an ideal flash point of around 70ºF. The liquids I have to work with are 200 proof (100%) isopropyl alcohol (2-propanol) and aliphatic hydrocarbon mixture (aka hydrotreated petroleum distillates). What I'm looking for is the ideal ratio of alcohol to petroleum to mix in order to get a flash point close to 70ºF.

So far, I have collected this info on the liquids:
  • Alcohol MSDS: goo.gl/bFnGg
  • Flash point: 53ºF
  • Petroleum MSDS: goo.gl/XWEKf
  • Flash point: 142ºF
  • Petroleum % by weight: 100%
  • Petroleum consists of hydrocarbons having carbon numbers predominantly in the range of C9 through C16 and boiling in the range of approximately 150.degree.C to 290.degree.C (302.degree.F to 554.degree.F).
    More info: goo.gl/eJvHK
    Search for "64742-47-8"

Is there a formula I can use to go about doing this? Unfortunately, I only have a high school chemistry and physics background, so the farthest I have got is google :P

Thanks,
JGAN
 
Engineering news on Phys.org
Hi, a precise calculation, based in thermodynamics, is quite involved. However, if you Google something like "Effect of Additives on the Flash Point of Flammable Liquid" you will find that you can begin by adding water to the alcohol to raise its flash point (for example, a mixture of .7 water & .3 methanol seems to raise the flash point by 25 degrees C). You would then add this mixture to the petroleum.
 
One thing that makes this harder is whether the mixture will be 100% soluble or not- a two phase system is a strong possibility if even a slight amount of H2O contacts this, and then the vapor pressure exerted by the alcohol phase will rule the flashpoint as if the other was not even there.

If higher alcohols are available and exert the proper polar solvency for the application you propose for the mixture, they will ensure complete miscibility, be less prone to water breaking the phases, and will have a better flash point. They would also be able to mod the flash point of isopropanol so some of that can be incorporated.
 

Similar threads

Jet Fuel, JP-5, JP-8 & DFM: Properties, Chemical Composition & Toxicokinetics
  • · Replies 17 ·
Replies
17
Views
65K
Simple Distillation Homework: Methanol, Pentanol, & Azeotrope
  • · Replies 3 ·
Replies
3
Views
14K