MASS TRANSFER REACTIONS BETWEEN VOCS, AQUEOUS & VAPOR PHASES IN THE SUBSURFACE

挥发性有机化学品通常被释放到环境中， 非水相液体（NAPL）通过表面溢出，储罐 危险废物填埋场的渗漏或沥滤。的存在和 地下系统中非水相液体的行为尚未得到充分考虑 在以前的含水层建模工作。这是两个同伴之一 项目将在密歇根大学进行，以解决这一问题， 缺陷该项目将特别关注以下物质的传质： 从有机液相到水相和气相的化学品。 实验将进行检查挥发性有机化合物的质量转移， 不混溶有机液体在填充柱中的残余饱和度， 多孔介质液-液和液-气相间传递 过程将根据适当的质量传递来描述 系数和驱动力。特征之间的相关性 多孔介质（例如，粒度分布）和传质 将建立系数。流速、配置的变化 不混溶相、初始润湿流体和柱长度的比例将 允许量化质量传递速率。广义 描述传质和传输动力学的数学模型 通过多孔介质将被写入，以帮助在分析的 从这些实验中获得的数据。该模型将包括一个质量 余量为非水液相。局部平衡分配 和动力学传质表达式将作为选项纳入 描述相间质量交换的模型。来自当地的照片 平衡将使用几个现象学传质建模 与不混溶相的性质有关的表达式和 多孔介质。基于这种分析，特定配置的质量 最接近观测数据特征的传递模型将是 在计算机模拟器中识别并作为"子模型"纳入 在同伴项目中开发。

Volatile organic chemicals are commonly released to the environment as non-aqueous phase liquids(NAPL) via surface spillage, storage tank leakage, or leaching from hazardous waste landfills. The presence and behavior of NAPL in subsurface systems has not been adequately accounted for in prior aquifer modeling efforts. This is one of two companion projects to be conducted at the University of Michigan to address that deficiency. This project will focus specifically on the mass transfer of chemicals from organic liquid phases to aqueous and vapor phases. Experiments will be conducted to examine VOC mass transfer from immiscible organic liquids at residual saturation in packed columns of porous media. Liquid-liquid and liquid-vapor interphase transfer processes will be described in terms of appropriate mass transfer coefficients and driving forces. Correlations between the characteristics of the porous media (e.g., grain size distribution) and the mass transfer coefficient will be established. Variations in flow rate, configuration of the immiscible phase, initial wetting fluid, and column length will permit quantification of rates of mass transfer. A generalized mathematical model describing the kinetics of mass transfer and transport through the porous media will be written to aid in the analysis of the data obtained from these experiments. The model will include a mass balance for the non-aqueous liquid phase. Local equilibrium partitioning and kinetic mass transfer expressions will be incorporated as options in the model to describe the interphase mass exchange. Departures from local equilibrium will be modeled using several phenomenological mass transfer expressions related to the properties of the immiscible phase and the porous media. Based on this analysis, that specifically configured mass transfer model which most closely characterizes the observed data will be identified and incorporated as a "sub-model" in the computer simulator being developed in the companion project.