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Analysis of mathematical models of underground coal gasification

Thesis/Dissertation ·
OSTI ID:5930616
Results are reported of a survey and comparison of forward combustion underground coal gasification (UCG) models that are available in the public domain. The six models obtained for study were mathematically analyzed to determine their conceptual completeness and computational complexity. The computer code for each model was implemented on the University of Wyoming CDC CYBER 730/760 computer system. Computed analyses were made with each of the programs using data to simulate six representative UCG field tests. Four of the field tests were air injection experiments and two were oxygen/steam. Modifications were necessary to two models in order for them to simulate oxygen/steam injection experiments. A mistake in the computer code for one model was discovered and corrected; this enabled the code to execute with data from one field test for which the original version had failed. An alternate numerical solution technique for one mdoel was studied, and improved correlations for the model were developed. An approximate analytical solution to the model was obtained that is valid over the region where difficulties were encountered, using both multiple shooting and collocation numerical solutions. The applicability of each model to the various conditions occurring in the different field tests was determined.
OSTI ID:
5930616
Country of Publication:
United States
Language:
English