The sealing ring of the external floating roof tank is prone to petroleum gas leakage due to material aging and oil corrosion. Petroleum gas leakage and diffusion easily accumulate above the floating deck. When it is within the explosion limit range, there will be the risk of explosion and fire. To deal with the explosion accident of storage tank caused by the concentration distribution of petroleum gas leakage for the sealing ring, and to study the influence of petroleum gas diffusion and concentration distribution after sealing ring leakage on the control area above the floating deck in the tank farm environment, this paper established numerical models of sealing ring leakage under different liquid level heights for 10 × 10⁴ m³ external floating roof tank. Through numerical calculation, it is found that the diffusion concentration of petroleum gas is related to the wind speed, the range of the control area above the floating deck, and leakage when sealing rings leak at different liquid levels. Through dimensionless analysis, the functional relationship of gas leakage diffusion concentration distribution under different liquid level heights of external floating roof tank sealing rings is verified by numerical calculation results. The results show that the numerical results are consistent with those predicted by the formula.

外浮顶罐的密封圈由于材料老化和油品腐蚀，容易发生石油气泄漏。石油气泄漏和扩散容易在浮甲板上方积聚。当在爆炸极限范围内时，会有爆炸和火灾的危险。针对密封环泄漏石油气浓度分布引起的储罐爆炸事故，研究密封环泄漏后石油气扩散浓度分布对罐内浮台以上控制区的影响农场环境，本文建立了10×10 ⁴  m ³不同液位高度下密封圈泄漏的数值模型外浮顶罐。通过数值计算发现，石油气的扩散浓度与风速、浮台上方控制区范围、不同液位密封圈泄漏时的泄漏量有关。通过无量纲分析，通过数值计算结果验证了外浮顶罐密封圈不同液位高度下气体泄漏扩散浓度分布的函数关系。结果表明，数值结果与公式预测的结果一致。