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Show COMBUSTION CHARACTERISTICS OF FINE-GROUND COAL Charles L. Brlceland Mark J. Khinkis Richard T. Waibel Energy Development Center Institute of Gas Technology Chicago, Illinois 60632 ABSTRACT Direct combustion of pulverized coal is becoming increasingly attractive for many utility and industrial boilers, process heaters, and furnaces. However, standard-ground pulverized coal burns with lower specific heat release than oil, and the furnace exit gas temperature for coal combustion must be low to prevent slagging of the convective passes, which in many cases makes conversion from oil to standard pulverized coal firing impractical. The Institute of Gas Technology (IGT) has conducted a program for the Pittsburgh Energy Technology Center (PETC) to experimentally determine the effect of coal particle size on pulverized coal flame and slagging/fouling characteristics for boiler application. The replacement of high-cost liquid fuel with coal in utility and industrial boilers is the final goal of this project. An on-line milling and feeding system was constructed at IGT's Applied Research Facility. The research furnace was equipped with a boiler type burner, water cooling radiative tubes along the combustion chamber walls, and gas cooling convective tubes in the flue. Tests were performed with firing rates from 470 kW (1.6 X 106 Btu/hr) to 730 kW (2.5 X 10 Btu/hr), ambient combustion air temperature, and 20% excess air. Most of the combustion trials were conducted at the high furnace exit gas temperatures typical of boilers designed for natural gas- and oil-firing. The coal fired in the tests was a highly volatile bituminous coal from Pittsburgh No. 8 seam. 1 |