Laboratory simulation of underground gasification of Eastern bituminous coals

In support of the Department of Energy's Eastern Underground Coal Gasification (UCG) program, we are conducting a series of small-scale laboratory gasification experiments. The purpose of these experiments is to develop a better understanding of the gasification process in Eastern bituminous coals, particularly as it differs from that previously observed in Western sub-bituminous coals. The results of this work will be used as input to both our modeling efforts and to upcoming field tests. We have to date conducted gasification experiments using both a Western subbituminous coal (for reference) and an Eastern bituminous coal (Illinois Herrin No. 6, from the site of the proposed field tests). The sub-bituminous coal exhibited the same phenomena observed in field tests, including high char reactivity, low structural strength, and cavity growth dominated by thermal-mechanical mechanisms. The bituminous coal experiments, on the other hand, were difficult to ignite and showed much lower char reactivity and much higher mechanical strength. Initial cavity growth was controlled by char reaction mechanisms rather than coal roof spalling. These results suggest that achieving enhanced char combustion and gasification rates is critical to the success of bituminous UCG. 8 refs., 15 figs., 4 tabs.