The coal cleaning process generates substantial quantities of coal fines mixed with mineral matter. An estimated 40-million tons of coal fines are discarded to waste ponds each year. The use of coal-water fuel, prepared from plant coal and water, had been studied since 1960's and was under extensive research in late 1970's and through 1980's due to higher oil prices. The coal-water fuel was developed as alternate to oil fuel. It offers lower emissions during transportation and storage compared to solid coal handling. This paper deals with the flame stability of coal-water fuel, prepared from 85% plant coal and 15% recovered fines slurry. This is part of the work done to investigate the use of recovered fines slurry blended with plant coal in utility boilers. The combustion tests of coal-water fuel were carried out at three different firing rates, 140 lb/hr (0.8 MMBtu/hr), 112.5 lb/hr (0.65 MMBtu/hr) and 85 lb/hr (0.5 MMBtu/hr). Flame stability of coal-water fuel had been a problem as flame was unstable and supported with either gas or oil burner. Also the turn down ratio is limited due to unstable flame at lower firing rates.
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