Effect of Thermal and Structural Properties on the Growth of an Underground Coal-Gasification Cavity

摘要

In field and laboratory studies of underground coal gasification, the growth of the cavity about the initial link has varied from the approximately circular cross section observed in the Hanna Basin coals, to cavities with 2:1 ratios of vertical to horizontal growth as has been observed in the Powder River Basin coals. A model based on the thermal and structural behavior of coal has indicated that these shapes are dependent on the site specific properties of the coal. In this study, the properties of coal samples taken from the Big Seam near Centralia, Washington, are used in the model to examine the cavity growth in that seam. Due to the high variability of these properties, sensitivity studies are included to determine a range of probable shapes. The results obtained from the model are then compared with field data. The result of the study is a prediction that the vertical-to-horizontal growth ratios will vary from 1:1 to 1.4:1 in underground tests in the Big Seam. 3 tables. (ERA citation 08:045352)