Flammability Limits of Combustible Gases at Elevated Temperatures and Pressures: Recent Advances and Future Perspectives

20 ABSTRACT: 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 15 8 10 1 5 0 0 flammable mixtures LFL - -a- -Gan 2018-+--Cui2016 - - --Wiezba1999--r- Huang 2021 - diamond -Zhu 2019 - -Gao 2018 200 temperatures and high pressures, which causes difficulties in temperate ec 250 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. 40 Q A' 30 ig 20 4 10 I flammable mixtures -Chen 2003 - - Hottappels 2002 - - Vanderstraeten 1997 -Zhu 2019 -R- Gao 2017 LFL 50 100 150 300 350 0 0 0.5 1.0 pressure, MPa 1.5 20