New insights into the ignition characteristics of liquid fuels on hot surfaces based on TG-FTIR

There are many potential hazards related with hot surface in industrial processes. Therefore, the ignition characteristics of liquid fuels on hot surfaces play an important role for fire safety engineering involved with energy utilization. In this study, thermogravimetric analysis and hot surface tests were systematically conducted for some typical liquid fuels. In the hot surface tests, ignition parameters were measured and investigated, including ignition probability and characteristic ignition temperature. It was found that the ignition of liquid fuel on the hot surface was probabilistic. The boil -over phenomenon was observed for transformer oil when the hot surface temperature was above 693 K, where the liquid fuel burned over the pan. For the three liquid fuel selected in our studies, the order of lowest ignition temperature was not consistent with the order of the kinetic parameter. Furthermore, the comparative analysis revealed that the lowest ignition temperatures with ignition probability of 5% were observed to be within the temperature ranges of combustible gases generation, indicating that the ignition of the liquid fuels on the hot surface was significantly influenced by the combustible gas generated during the evaporation and thermal decomposition. Finally, the model describing the profiles for the concentration and temperature of combustible vapor was introduced to provide a detail explanation for the ignition mechanism of liquid fuels on hot surfaces. The established model could provide scientific basis to the fire risk assessment for liquid fuel fire caused by the hot surface, and further optimize the safe usage of liquid fuels.