Volumetric Heating of Oil Shales by Electromagnetic Methods. Volume 6. Heat Conduction in Heterogeneous Media and Volumetric Heating of Oil Shales by Electromagnetic Methods

摘要

The problem of volumetric heating of oil shales by electromagnetic methods and the effects of layering on heat conduction in oil shales are studied theoretically. This study includes both a detailed examination of heat conduction in composite media, and the development of a numerical model to describe the heating process. A new solution to a heat conduction equation in heterogenous materials is developed which includes both the effects of inclusions and contact resistance. The solution is presented in terms of the associated Green function and numerical results are displayed. A new solution to the heat conduction equation is presented for materials which consist of constituents whose thermal properties vary in a discontinuous manner. This solution is also presented in terms of a Green function and an iteration technique is developed to solve the related eigenfunction problem. Numerical results are exhibited for heat flow in layered materials. A two dimensional numerical model which describes electromagnetic heating of oil shales is developed which includes equations for temperature, pressure, saturations, chemical reactions, mass conservation, and source terms. The gases are all assumed to form one bulk species and the oil is assumed to remain in liquid form. The chemical reactions include pyrolysis of kerogen and char, release of bound water, coking, and decomposition of carbonates. Porosity and permeability are dynamic functions of the organic materials. Calibration of the model is accomplished by comparison of the model results with experimental data obtained by IITRI. Nonlinear relationships for viscosity, thermal properties, and source terms are used as inputs to the model. A finite difference approximation to the differential equations is derived and solved using Newton's iteration technique. Numerical results are included and a preliminary study of the optimization of the heating process is presented. 44 refs., 63 figs. (ERA citation 10:046095)