Experimental evaluation of the formation of an explosive environment over the floating roof of an oil storage tank during pumping out of a neighboring tank in case of fire

Introduction. The study of the formation of explosive concentrations of vapors of flammable liquids (hereinafter referred to as flammable liquids – LVL) in the gas space of a tank with a floating roof when pumping oil out of it during a fire of a neighboring tank in oil storage facilities in Vietnam. Goal and tasks. Consider the reasons for the spread of fire from a burning vertical, steel floating-roof oil storage tank (hereinafter – RVSPK) to an adjacent non-burning RVSPK with oil. Develop a program of experiments. Create an industrial experimental setup for measuring explosive and fire hazardous concentrations of light oil fractions above the floating roof of a full-scale reservoir with a volume of 65 000 m3 of crude oil. Conduct an experiment to measure the concentration of light fractions of oil over a floating roof during pumping. To experimentally determine the possibility of the formation of explosive and fire hazardous concentrations of light fractions of oil (methane), within the lower concentration limit of flame propagation, in the steam space above the floating roof of the RVSPK in real time in the process of lowering the level of the floating roof during pumping out oil in the event of a fire on a neighboring tank. Method. Analysis. Full-scale experiment. Results and discussion. A natural experiment was carried out. The results of studies on the distribution of concentrations of combustible vapors of light fractions of oil (methane) in the gas space above the floating roof of a non-combustible tank of 65000 m3 during oil pumping are obtained. The most probable places of formation of explosive concentrations are determined. To reduce the fire load, the risk of fire spread, possible damage and death caused by fire in large-capacity RVSPK oil storage facilities in Vietnam, it is proposed to pump oil from the adjacent RVSPK to the burning RVSPK in combination with concentration control in the aerodynamic shadow zone inside the RVSPK gas space. Conclusions. When crude oil is pumped out of the tank in the annular zone around the floating roof, an explosive methane-air mixture zone is formed with a methane concentration reaching the lower concentration limit of flame propagation. Keywords: fire, fire and explosion safety, reservoir, floating roof, concentration, combustion.