Plenary Session:

Title:        Spontaneous combustion of low rank coal; Measurement of the critical self-ignition temperature
Authors:     Kyuro Sasaki, Yuichi Sugai, Salmawati, Wataru Kawasaki
Abstract:   World's reserves of low-rank coals are about 60% of total coal reserves. It has been expected to expand their utilizations for coal gasification plants. However, they have not been fully developed due to high self-heating rate. It has been well-known that the spontaneous combustion of coal has been observed after the internal pile temperature is over the critical self-ignition temperature, CSIT, which strongly depends on the pile volume. Although previous laboratory measurements on self-heating rate of coal have been done using quite small amount of coal samples, it is required to carry upscale experiments using low-rank coal volume of 1m3 order, because the coal volume is the dominant physical factor than other factors to induce spontaneous combustion. In this keynote presentation, the spontaneous combustion of lignite classified as low-rank coal has been focused by introducing both of laboratory experiment (pile size; 2.5 to 10 cm) and upscale experiment (pile size; 25 to 100 cm) using the wire-mesh basket test up to 1m3 in its volume in order to clear (a) temperature-time curves in the coal pile for different size of the baskets and ambient air temperature; (b) CSIT measurement for the coal pile volume; (c) extrapolate the CSIT value against 100 m3 order in industrial stockpile volume, (d) simulate spontaneous combustion of residual coal in the mine goaf based on the critical self-ignition temperature and thermal characteristics of coal piles.

Pages:        002-002

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