Atmospheric fluidized bed combustion of high sulphur high volatile NE region coals of India

In order to investigate in situ sulphur absorption by limestone as well as combustion characteristics of high volatile high sulphur N.E. Region deals of India in fluidized-bed, steady state experiments were conducted in a 0.67 sq. meters cross-sectional area fluidized bed combustor (10 T/hr hot water capacity). Flue gas was monitored continuously with on-line gas analysis system. Calcium to sulphur molar ratio ranged from 3 to 4, the average bed temperature from 780 to 866 degree centigrade and excess air from 19.2 to 47.4 per cent. It is observed that it is difficult to maintain bed level at Ca/S molar ratio 3. Optimum sulphur retention temperature is in the range of 830 to 850 degree centigrade. The combustion efficiencies are in the range of 82 to 88 per cent and have been found to rise with bed temperature. Heaat transfer co-efficients in fluidization zone ranged from 146 to 215.8 kcal/hr/meters square/degree centigrade and in the freeboard from 14.1 to 23.98 kcal/hr/meters square/degree centigrade.