The study of self-ignition temperature dependence on the concentration of flammable liquid vapours
Authors:   State Fire Academy of EMERCOM of Russia, BEGISHEV Ildar R. , REFORMATSKAYA Irina I. ,   State Fire Academy of EMERCOM of Russia, LANIN Sergey N. ,   Lomonosov Moscow State University, ASHCHEULOVA Irina I. ,   State Fire Academy of EMERCOM of Russia, PETRILIN Dmitry A. ,   State Fire Academy of EMERCOM of Russia
Published: April 2024

Purpose. The currently used methodology for determining flammable liquid self-ignition temperature, which is well-known as the “drop method”, makes it impossible to obtain the dependence of self-ignition temperature on flammable liquid concentration that corresponds to theoretical concepts. It is related to the fact that while conducting experiments a flammable liquid is injected into the neck of an open heated vessel. The preliminary calculation of the required quantity of flammable liquid for creating its given concentration does not take into account the substance loss when it is injected into the reaction vessel. The main aim of the research is to improve the methodology for determining flammable liquid self-ignition temperature depending on the concentration of its vapors. Methods. To study the relationship between the volume of flammable liquid injected into the neck of the reaction vessel heated to a certain temperature and self-ignition temperature of this liquid the method of experimental data analysis was used. The experimental results were obtained with the help of the experimental method that involved injection of different volumes of flammable liquid and then recording flame presence or absence. Findings. A relationship was established between the fuel concentration in the vapor-air mixture and the volume of the injected sample. The methodology for determining the flammable liquid self-ignition temperature was corrected. Research application field. The results can be used in determining flammable liquids self-ignition temperature of various chemical composition, as well as in the educational process when students carry out a laboratory work on determining a flammable liquid self-ignition temperature depending on its concentration. Conclusions. The findings of the research allowed the authors to draw the following conclusions: 1) in the methodology for determining a flammable liquid self-ignition temperature when calculating the volume of the injected sample to create the required concentration of fuel in the vessel, the flammable liquid losses occurring on its injection into a heated reaction vessel were not taken into account. It is recommended to use a correction factor of 2 to take into consideration losses in calculation formulas. 2) to equally distribute the concentrations of the used fuel on the graph of the dependence under study within the lower and upper flammability limits, to calculate the volume of a flammable liquid, fuel concentration must be preset as follows: ϕ1 = 1,2ϕн, ϕ2 = ϕстех, ϕ3 = 1,8ϕстех, ϕ4 = 0,8ϕв. 3) the methodology for determining the self-ignition temperature of a flammable liquid is also valid in case of using high molecular weight aliphatic (non-cyclic) alcohols, for example, butanol, pentanol, hexanol.