土壤甲苯泄漏扩散及影响因素的三维数值模拟

Three-dimensional Numerical Simulation of Toluene Leakage and Influencing Factors in Soil

为了分析石油类污染物在土壤中的自然渗流规律,提高事故的应急控制能力,利用CFD软件对甲苯在土壤中的泄漏过程进行模拟分析,得出了发生泄漏后污染物在土壤中速度场的时空分布规律及土壤孔隙度和含水率对污染物扩散的影响。模拟结果表明,甲苯在土壤中的迁移距离随泄漏时间和泄漏量的增大而增加;速度场分布规律为"轴向为主、径向为辅→径向为主、轴向为辅→轴向扩散";甲苯主要集中在土壤模型0~20 cm内,土壤孔隙度和含水率越高,污染物在土壤中轴向的迁移距离越大,扩散越快。因此,在污染物泄漏时应及时进行治理,避免随时间和泄漏量的增加使土壤中污染物含量增加而导致扩散范围增大,建议石油企业在未来油罐区的选址上应尽量选择含水率和孔隙度较低的区域,防止污染扩大化。

In order to analyze the natural seepage law of petroleum pollutants in soil and to increase the emergency control ability, the leakage process of toluene in soil is simulated and analyzed by CFD software, and the temporal and spatial distribution of the pollutant in the soil and the influence of soil porosity and water ratio on the pollutant diffusion after leakage are obtained. The simulation results show that the migration distance of toluene in soil increases with the increase of leakage time and leakage rate,and the distribution of velocity field is as follows： axial is main,radial is complementary → radial is main, axial complementary → axial diffusion. Toluene is mainly concentrated in 0 to 20 cm of the soil model. The higher the soil porosity and the water ratio, the longer the migration distance and the faster the diffusion of pollutants in soil. Therefore, in the case of pollutant leakage, it is necessary to make prompt treatment in order to avoid the increase of pollutant content in soil caused by the increase of time and leakage. Meanwhile, it is suggested that petroleum enterprises should chose areas with low water ratio and porosity when selecting the future location of the tank in order to prevent pollution enlargement.