Calculated values of fire and explosion hazards in accidents of gas-cylinder cars
Authors: Зуйков В.А. , Земский Г.Т. , Зуйков А.В. 
Published: June 2023

Рассмотрены свойства топлива для газобаллонных автомобилей: сжиженного углеводородного топлива (СУГ), компримированного природного газа (КПГ), сжиженного природного газа (СПГ) и водорода. Рассчитаны размеры взрывоопасных зон, образующихся при разгерметизации баллонов с топливом различной вместимости, а также давление взрыва паров топлива в зависимости от расстояния от аварийного баллона. Показано, что по размеру взрывоопасных зон наиболее опасными видами топлива являются СУГ, СПГ и пропан. На расстоянии 30 м от наружной установки наибольшее расчетное давление взрыва образуется при разгерметизации баллонов СУГ (50:50), затем в порядке убывания следуют баллоны с СПГ, баллоны с пропаном, с водородом и баллоны с КПГ. При этом для достижения давления взрыва 5 кПа необходимо следующее количество газов: водорода – 0,2 кг, СПГ– 2,5 кг, пропана, пропан-бутана (1:1) и КПГ – по 3,5 кг.

The purpose of this publication is to consider the fire and explosive properties of gaseous fuels for cars. The task is to obtain by calculation the sizes of explosive zones, as well as the values of the excess pressure of the explosion of gas-air mixtures of various compositions in an open space. The article provides a brief digression into previously published materials on the use of gas-cylinder cars running on alternative fuels. It is noted that publications on the use of gas-cylinder cars can be divided into three areas: 1) containing information about the properties of fuels and justifications for their use; 2) containing the development of equipment for the use of fuel in cars; 3) containing conditions of fire and explosion-proof use of fuels. This publication applies to the third area. There are calculated the initial mass flow rates of the liquid and vapor phase of propane through holes of various diameters, as well as the sizes of explosive zones formed during equipment depressurization. It is shown that with an increase in the intensity of the outflow, the size of the explosive zone increases, and with an increase in the velocity of the air flow, the size of the explosive zone decreases. The initial flow rates of methane gas from cylinders under pressure of 15 and 25 MPa through holes of different cross-sections are also calculated. The flow rate increases both with an increase in pressure and an increase in the area of the hole. The sizes of explosive zones during depressurization of cylinders of various capacities with fuels are determined by calculation: methanon at an initial pressure in a cylinder of 20 MPa, liquid propane-butane at a pressure of 1.6 MPa, hydrogen at a pressure of 20 MPa. It is noted that according to this indicator, the most dangerous types of fuels are LPG, LNG and propane. Calculated data on the excess pressure of the explosion of gas-air mixtures in open space at different distances from cylinders with CNG, LNG, propane, propane-butane and hydrogen are presented. It is shown that at a distance of 30 m from the cylinders, the highest calculated explosion pressure is formed when the LPG cylinders are depressurized (50:50), followed by a cylinder with LNG, propane, hydrogen and CNG. At the same time, to achieve an explosion pressure of 5 kPa, the following amounts of gases are necessary: hydrogen – 0.2 kg, LNG – 2.5 kg, propane, propane-butane (50:50) and CNG – 3.5 kg each.