基于TMVOC模拟的大气压力波动对土壤中苯迁移转化影响研究

Research on the effect of atmospheric pressure fluctuation on the migration and transformation of benzene in soil based on TMVOC simulation

为探究大气压力波动下苯系物(BTEX)的迁移转化规律,提升石化污染场地土壤地下水污染治理水平,以西北某炼化场地为研究对象,结合室内土柱试验与TMVOC软件模拟,开展BTEX泄漏模拟,研究不同大气压力波动幅度下苯在包气带与含水层中的迁移转化规律。结果表明:大气压力循环波动会引起包气带中的气相苯发生相间非平衡态迁移,导致气相质量分数增加0.1%~0.5%;非水相液体(NAPL)污染物转化为气相污染物,进而通过大气挥发是主要的质量损失方式,该转化会造成场地及周边的大气环境污染;同时大气压力波动的幅度与气相转变发生时间存在负线性相关关系。研究显示,大气压力波动显著影响了苯的相态转化与迁移过程,促进了苯的相态转化,使得更多的苯转化为气相,造成大气环境污染。

In order to explore the migration and transformation law of benzene series(BTEX)under the fluctuation of atmospheric pressure,and improve the control level of soil and groundwater pollution in petrochemical-polluted sites,a refinery site in northwest China was taken as the research object and,combined with indoor soil column experiment and TMVOC software simulation,BTEX leakage simulation was carried out to explore the migration and transformation law of benzene in the vadose zone and aquifer under different amplitude of atmospheric pressure fluctuation.The results show that the atmospheric pressure cycle fluctuation can cause the gaseous benzene in the vadose zone to migrate to the non-equilibrium state,resulting in the increase of the gaseous mass fraction by 0.1%-0.5%.The conversion of non-aqueous liquid(NAPL)phase pollutants into vapor phase pollutants and their volatilization through the atmosphere is the main way of leakage quality loss,and this transformation will cause atmospheric pollution in the site and its surroundings.At the same time,the amplitude of atmospheric pressure fluctuation is negatively correlated with the time of gaseous transition.The study shows that the atmospheric pressure fluctuation significantly affects the phase transformation and migration process of benzene,promotes the phase transformation of benzene,and makes more benzene transform into gas,resulting in atmospheric environmental pollution.