The flammability limits are essential
parameters that reflect the
risk of a gas explosion and are affected by the temperature, pressure,
and inert gas. Many industrial processes are run at high temperatures
and high pressures. Incidents involving combustible gas explosions
are frequent; however, issues with gas explosion safety at high temperatures
and pressures are never addressed. There have been no substantial
advances in theoretical prediction for a long time and a dearth of
perfect theories and systematic data collection. Many factors, such
as thermal decomposition and slow oxidation, need to be considered
at high temperatures and high pressures, which causes difficulties
in measurements and inadvertently increases the potential explosion
risk. This paper reviews the historical experimental research on the
flammability limit of combustible gases at elevated temperatures and
pressures and the prediction model of flammable limits by examining
the influence mechanism of high temperatures and high pressures. An
overview of the theory of flammability limits, criterion of flammability
limits, experimental studies, and current status of flammability limit
prediction models for combustible gases at high temperatures and pressures
are highlighted to help establish and improve the accuracy of flammability
limit prediction models at high temperatures and pressures.