Study on Leakage and Diffusion Law of 'Large Breathing' Loss of Gasoline Storage Tank Based on PHAST

摘要

Volatile organic compounds (VOCs) from breathing loss of storage tanks account for more than 50% in chemical enterprises, so it is necessary to study the leakage and diffusion law of breathing loss in tank areas. In this paper, the empirical formula of China Petrochemical system was used to calculate the "large breathing" loss of the internal floating roof gasoline tank, and the diffusion simulation of "large breathing" loss of a petrochemical gasoline tank was carried out by PHAST. Because there is no "breathing loss" model of tank in PHAST, a user-defined model was used to simulate the "large breathing" loss of gasoline tank with internal floating roof. The simulation results show that when the atmospheric stability is constant, the greater wind speed is, the larger diffusion distance of VOCs is at the same time. When the wind speed is constant, the more unstable atmospheric stability is, the larger diffusion distance of VOCs is at the same time. When the wind speed is constant, the more stable atmosphere is, the higher concentration of VOCs is at the same location. The more unstable atmosphere is, the higher wind speed is, the more VOCs could be enriched near the storage tank in downwind direction. The simulation results provide reference for safe operation and division of emergency area, and provides reasonable theoretical support for safety management and safety evaluation.