Desorption of Soil Contaminants During Steam Cleaning

这项研究是对热的基本原理的调查， 在蒸汽清洗过程中发生的传质 污染物吸附在土壤中。 热传递和 凝析油和天然气流量分析假设当地热 平衡、对流、分散、重力、毛细作用和 扩散和热毛细现象。 传质过程中， 相（固体，液体和气体）分析基于本地 非均衡假设。 界面传质 系数和比表面积通过 两相流的直接模拟 单元格 实验是在土柱中进行的， 具有受控初始平衡（固-气）的模拟物 注汽前的状态。 短暂局部 温度、毛细管压力和污染物浓度 (in液相和气相）进行测量。 的 实验结果将与预测结果进行比较 为了检验现象学单位的有效性 细胞动力学模型 拟议的研究将允许开发和 对热的孔隙水平分析的关键验证， 蒸汽清洗过程中土壤中的质量传递。 第一 时间，局部速度和局部饱和度的依赖性， 三相之间的传质速率为 通过直接模拟确定，并将得到验证 实验性的 结果也将是有价值的， 等温修复过程的分析/预测。

This study is an investigation of the fundamentals of heat and mass transfer occurring during the steam cleaning of contaminants adsorbed in soil. The heat transfer and the condensate and gas flow are analyzed assuming local thermal equilibrium, convection, dispersion, gravity, capillarity and diffuso- and thermo-capillarity. The mass transfer among the phases (solid, liquid, and gas) are analyzed based on local non-equilibrium assumptions. The interfacial mass transfer coefficients and the specific surface areas are obtained by a direct simulation of two-phase flow in a phenomenological unit-cell. Experiments are performed in soil columns using contaminant simulants with a controlled initial equilibrium (solid-gas) condition prior to injection of steam. Transient local temperature, capillary pressure, and contaminant concentration (in liquid and gaseous phases) measurements are made. The results of the experiments will be compared to those predicted in order to examine the validity of the phenomenological unit- cell based kinetic model. The proposed research will allow for the development and critical verification of the pore-level analysis of heat and mass transfer in soil during steam cleaning. For the first time, the local velocity and local saturation dependence of the mass transfer rates among the three phases will be determined by a direct simulation and will be verified experimentally. The results will also be valuable for analysis/prediction of the isothermal remediation processes.