Flammability envelopes for methanol, ethanol, acetonitrile and toluene
Journal of Loss Prevention in the Process Industries, 20 (2):
144--150 (March 2007)DOI: http://dx.doi.org/10.1016/j.jlp.2007.01.001
Abstract
The flammability envelope was experimentally determined up to the
point of vapor saturation for four flammable liquids: methanol, ethanol,
acetonitrile, and toluene. The experimental apparatus consisted of
a 20-L spherical chamber with a centrally located 10 J fuse wire
igniter. The liquid was injected and vaporized into the chamber via
a septum and a precision syringe. Nitrogen and oxygen were mixed
from pure components using a precision pressure gauge. Pressure versus
time data were measured for each ignition test. Flammability was
defined as any ignition resulting in an increase in pressure of 7%
over the initial pressure, as per ASTM E 918-83. All data were obtained
at an initial temperature of 298 K and 1 atm. The experimental values
of the LFL agreed well with published values. Limiting oxygen concentrations
(LOC) were also determined--although these were somewhat lower than
published values. The calculated adiabatic flame temperature (CAFT)
method was used to model the data using a threshold temperature of
1200 K. A reasonable fit of the flammability envelope was obtained,
although this could be improved with a higher threshold temperature.