包气带水气二相流CO2运移规律

利用土柱实验装置模拟CO₂在土壤中的迁移转化规律,重点研究湿润峰处水、气二相间污染物转化实验土柱长1m,过饱和CO2溶液浓度为748mg/L.分析表明水相运移受对流、弥散、反应及水-气质量传输机制控制,气相运移受对流、扩散和水-气质量传输机制控制.对土柱中水气二相动态条件下的取样方法进行了探索,确定了CO₂在渗透湿润峰水-气二相间分配系数为0.00061,表明水相向气相有一定传输,但不显著.可进一步为低中水平放射性废物地质处置安全评价及固体废物填埋处置环境影响评价提供定量科学依据.

Characteristics of Water-gas Two-phase CO2 Transport in Unsaturated Zone

The migration of CO₂ in soil was simulated through use of soil column, especially the transformation of CO₂ between water and gas phases at wetting front was studied. The soil column in the test was 1m long and the concentration of CO₂ solution was 748mg/L. Through analysis, it was shown that CO₂ migration in water phase was governed by advection, dispersion, reaction and mass transfer between water and gas phases, that in gas phase by advection, dispersion, mass transfer between two phases. Sampling method under dynamic condition of two phase flow in soil column was approached and mass transfer coefficient from water phase to gas phase was determined as 0.00061. This showed that there was certain mass transformation of CO₂ from water phase to gas phase and yet it was not so significant. This study can provide the quantitative scientific bases for safety assessment of geological disposal of low and intermediate level radioactive waste and environmental impact assessment of solid waste disposal by landfilling.