Влияние состава сжиженного природного газа на концентрационные пределы распространения пламени

Abstract

PURPOSE. The growth in the production of liquefied natural gas (LNG) in the Russian Federation sets the tasks of increasing safety level in this segment of the economy. The key parameter of the object of study under consideration is the concentration limits of flame propagation, which are determined by methane for LNG. However, the composition of LNG varies depending on its brand, storage process, transportation and loading and unloading operations. This fact requires a detailed analysis of the concentration limits of flame propagation for various LNG compositions. METHODS. The analysis of changes in the lower concentration limits of flame propagation (LFL) of methane, ethane, propane and butane presented in various reference data was carried out. The calculation method was used to establish LFL for the model composition of LNG vapors, and to determine the error between calculation and experiment. FINDINGS. The analysis of regulatory documents showed that the LFL value of 4.4 % for liquefied gas is the special case and requires clarification based on the LNG brand, storage process, transportation, and loading and unloading operations. The experimental data demonstrate the decrease in LFL of the model composition of LNG for class B compared to the calculated ones, the relative error does not exceed 14 %. RESEARCH APPLICATION FIELD. The results obtained will make it possible to differentiate the approach for determining fire and explosion hazard of LNG based on brand and life cycles of liquefied natural gas, which will allow applying a differentiated approach to the requirements for fire and explosion safety of LNG based on its composition. CONCLUSIONS. The concentration limits of flame propagation for LNG model compositions were calculated. Further directions of work on improving the methodology for calculating the parameters of liquefied natural gas explosion were determined, and the discrepancy between the normatively fixed LFL parameter of LNG vapors and experimental data was shown. It is proposed to take into account the brands and aging processes of LNG to predict the concentration limits of flame propagation.