高温气相抽提法处置有机物污染粘土的渗流-传热耦合作用机制研究

高温气相抽提技术是修复城市有机物污染粘土场地的最有效方法之一，其高温加热和负压抽提是一个复杂的热传导和对流传热过程。但由于对修复过程中土体传热特性及演变机理尚未明确，缺乏相应的理论和经验以指导工程设计，导致污染物去除效率和能耗问题一直制约着该技术的推广应用。本项目拟以南宁市河流冲积相有机污染粘土为研究对象，采用室内试验、理论分析、模型试验以及数值模拟等手段，首先研究高温作用下有机污染粘土的热传导与对流传热特性；然后通过微细观试验手段系统研究高温作用下土体结构与物相组成的演变规律，揭示土体热传导与对流传热特性的演变机理；最后围绕土体的气体渗流-传热问题，探索有机污染粘土在高温气相抽提过程的渗流-传热耦合作用机制，并建立相应数学模型和开展数值模拟。该项目的实施不仅可直接为高温气相抽提法修复有机污染场地的优化设计提供理论支持和技术指导，也将为其它高温条件下粘性土工程性质的热效应研究提供借鉴。

High temperaturel vapor extraction is promising approach in remediation of organic-contaminated clayey soil efficiently in cities. Heating and negative pressure extracting of soil are complex processes of heat conduction and convective heat transfer. However, heat transfer performance and evolution mechanisms of clayey soil during the remediation process have not been clarified, yet. Hence, the problems of pollutant removal efficiency and energy consumption hinderwide application of this technology. The research will perform on alluvial-fluvial organic-polluted clay in Nanning, and the heat transfer characteristics of clay will be analyzed by means of laboratory test, theoretical analysis, numerical simulation and model test. Firstly, characteristics of heat conduction and convective heat transfer of organic-contaminated clay will be studied in high temperature condition. Secondly, the evolution law of soil structure and phase composition under high temperature will be studied systematically with microscopic test to reveal the evolution mechanism of heat conduction and convective heat transfer of soil. Finally, the coupling mechanisms of seepage-heat transfer of organic-contaminated clay will be explored during high temperature vapor extraction process, the mathematical models will be established accordingly and numerical simulation will be carried out. This project will provide theoretical support and technical guidance for the optimal design of high temperature vapor extraction remediation of organic-contaminated sites. Besides, it will also provide references for the study of thermal effects of clayey soil engineering properties under other high temperature conditions.