Определение критической толщины пенного слоя для локализации и ликвидации пламенного горения проливов сжиженного природного газа

Abstract

PURPOSE. Increasing attention has been paid recently to applying high-expansion foam as means of localizing and eliminating liquefied natural gas spills flaming combustion. Scientific sources widely discuss the issues of foam expansion rate and elasticity, critical intensity of its supply and application rate. However, critical foam layer thickness is underestimated. At the same time one of the reasons for fire-fighting foam low efficiency is precisely the difficulty in providing required foam layer thickness. The purpose of this publication is to assess relationship between critical foam layer thickness and main parameters of localizing and eliminating liquefied natural gas flaming combustion. METHODS. Review of scientific works covering the issue of flammable liquids and liquefied natural gas foam fire extinguishment has been carried out. Methods for providing required foam layer thickness and determining foam fire extinguishing efficiency are analyzed. Results of researchers’ own experiments have been discussed, taking into account international and domestic experience in conducting similar studies. FINDINGS. Based on researchers’ own experimental data analysis, taking into account information from scientific sources, critical foam layer thickness assessment has been made for foams of various expansions used to localize and eliminate liquefied natural gas spills flaming combustion. Approximate foam layer thickness in centimeters should be at least a quarter of high-expansion foam expansion value. RESEARCH APPLICATION FIELD. The results obtained provide general understanding that to ensure efficiency of liquefied natural gas flaming combustion localization and elimination, it is necessary to ensure not only appropriate foam expansion and application rate, but also required foam layer thickness. The results can be used in scientific research and educational process, as well as by fire services and emergency rescue units in elimination of accidents accompanied by liquefied natural gas spills flaming combustion. CONCLUSIONS. Foam layer thickness is the key parameter for liquefied natural gas spills foam fire extinguishment and providing controlled burning technology. Depending on foam supply intensity the necessary condition for providing liquefied natural gas flaming combustion localization and elimination is to achieve or exceed critical foam layer thickness. Critical foam layer thickness depends on foam expansion ratio. As foam expansion ratio increases, critical foam layer thickness rises, its value can exceed two or more meters.