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Show Introduction The objectives of the study were to determine the unique combustion, emission, and operational characteristics associated with the fluidized-bed combustion of a minus 200 mesh char. In general, the experiments confirmed the char's highly reactive nature and excellent flame stability despite the char's low volatile matter content. These findings are in close agreement with other combustion studies conducted with this char in a pulverized fuel boiler and pressurized fluidized-bed combustor. Aside from the excellent combustion characteristics, emissions were easily controlled within Federal guidelines for all the tests. The major obstacles encountered in the tests were a direct result of the char's small particle size. The char tended to compact under its own weight in the feed hoppers, resulting in bridging and ultimately intermittent feed to the combustor. Although the compaction problem was solved early in study, gravity feed problems associated with the char warrant special consideration when designing material handling systems for large-scale combustion facilities. The other size related problem surfaced during the shakedown tests for this study. Char combustion occurred predominately at the top of the limestone bed and in the freeboard areas of the combustor. The elevated combustion zone was attributed to entrainment of the char particles in the combustor's fluidizing gas stream. Although the char particles were highly reactive, the high surface area to particle volume ratio provided the potential for particle entrainment in the combustor's gas flow, subsequently carrying the char particles to the top of the bed before complete combustion occurred. Background Char is a by-product of several coal conversion processes. Thus, if char can be utilized as a reliable fuel source in existing or newly developed combustion systems, the overall efficiency of the conversion process will 22-2 |