| OCR Text |
Show pyrites to react with air to form Fe„0„. Therefore, the size of particles must be as small as possible, the burning of coal must be taken place under the air-rich condition and the coal particles must be fed without any downward momentum. This approach has been tried in the furnace at Tampa Electric Co., but the downward momentum of the coal particles is not totally eliminated. The downward momentum is produced by the downward inclination of the coal feeder, hence it can be corrected either by adjusting the setting angle of the coal feeder if possible or by modifying the outlet of the feeder in such a way that the coal particles will go upward at the exit of the feeder. One possible outlet shape of the feeder is shown in Fig. 1. Existing nozzle Additional part Fig. 1 Modified Coal Feeder for Upward Momentum The second method will be accomplished if the temperature of the slag can be kept at 3000°F. Through the consideration of the chemical reactions of iron compounds in the combustion of coal, it is expected that the iron in the ashes may present in the following forms, Fe, FeS, FeS? and Feo0 . To reduce the deposit of the iron and its compounds on the furnace floor, the temperature of the slag must be kept above the melting points of these substances which are given in Table 1. Table 1. Melting Points of Iron and Its Compounds Fe FeS FeS2 Fe203 2802°F 2179.4 - 2190.2°F 2139.8°F 2849°F A |
