土壤气相抽提作用机制探讨和基本数学模型建立

SOIL VAPOR EXTRACTION:MECHANISMS AND BASIC MATHEMATICAL MODEL

土壤气相抽提 (SVE)是全球石油污染土壤修复的迫切需求下应用的新兴原位技术 ,其理论相对滞后 ,有必要进行系统研究。SVE涉及多学科交叉 ,土壤体系中包含了物质在气—液 (水 )—液 (油 )—固等多相间各种复杂的迁移、转化和物理化学行为 ,本文根据多孔介质流体动力学理论和化工传递原理分析了气相抽提过程中污染物的迁移机制和多相传质关系 ,在近实际假设条件下提出了一套任意维数下SVE基本数学模型 ,严格导出了土壤体系中流体的运动方程、污染物质量方程和污染油的衰减方程等主要控制方程 ,研究结果可作为SVE理论分析和工程设计的基础。

Soil vapor extraction (SVE) as an emerging in-situ remediation technology has been applied to remove subsurface pollution of petroleum chemicals all over the world. Although the technology has found more and more application, theoretical investigations to improve its designs and practices should continue systematically. For contaminants and fluid mediums in SVE, there exist different types of transfers, conversions and physicochemical behaviors because of the complicated multiphase system of gas-water-oil(NAPL)-solid. To make certain these processes, interdisciplinary approaches should be employed. In this paper, a basic mathematical model of SVE is presented according to the dynamic theory of fluids in porous media and the transition theory in chemical engineering with some applied assumptions. Some momentum equations, mass conservation equations and NAPL depletion equations aimed at describing SVE processes have been derived.