海上事故有害气体的扩散研究 ——以"桑吉"轮撞船事故为例

发生海上事故后，为对周边海域船只和人员进行疏散及为应急处置提供科学依据，并实现对不同检测位置检测浓度的校正，需要对事故有毒有害气体的扩散进行计算。本文先通过经验公式计算，模拟事故船舶自然燃烧，而后采用高斯烟羽模型，通过结合事故现场的风浪等水文气象参数，构建海上事故有毒有害气体扩散模型。该模型在改进的高斯烟羽模型的基础上，通过与 ArcGIS 结合，实现事故海域区域范围内有害气体扩散定量可视化，实验结果表明，“桑吉”轮撞事故中，有害气体沿向下风向西北处扩散，以事故点为起点向西北方向划线为轴线，宽幅选取 4 km 范围，最高浓度区域是以事故点下风向 3 km处为圆心，500 m 为半径的圆形区域，浓度可以达到 4* 10-5 mg/m3，边缘处气体浓度已低至 0.5 * 10-5 mg/m3。其模型简单且可以直观体现有毒有害气体扩散范围。

Study on the diffusion of harmful gases in marine accidents: Sanchi ship collision accident case

When an accident happened at sea, in order to conduct evacuation of vessel personnel in surrounding sea areas and to provide scientific basis for emergency disposal, the calculation of toxic and harmful gases diffusion in accidents need to be calculated, so that the concentrations detected at different detection locations can be corrected. In this paper, the empirical formula is used to simulate the natural combustion of the accident ship, and then the Gaussian plume model is used to construct a toxic and hazardous gases diffusion model for marine accidents by combining wind and waves and other hydrometeorological parameters at the accident site. The model is based on the improved Gaussian plume model and combined with ArcGIS to realize the quantitative visualization of harmful gas diffusion in the area of the accident. In Sanchi ship collision accident case, results indicate that the harmful gas diffuses along the northwest of the downwind direction, starting from the accident point. Scribe to the northwest as the axis, wide selection of 4 km range, the highest concentration area is centered on the 3 km of the accident point down the wind, and the largest concentration is in the circular area of 500 m radius, the concentration can reach 4* 10-5 mg/m3 , the gas concentration at the edge has been reduced to 0.5 * 10-5 mg/m3 . The model is simple and can visualize the diffusion range of existing toxic and harmful gases.