| OCR Text |
Show where Achar denotes the ash content in char sampled at each position from nozzle outlet, and A 0 is the ash content of the proximate analysis of test fuel. The burn out rate of EP dust takes the highest values all along through the furnace, while that of the semianthraci te is the lowest. Such a good combustion properties, in spite of its low volatile content is thought to be caused by the porous structure and large specific surface area of EP dust. Figure 7 shows the amount of consumed oxygen in rising the temperature from room temperature to 250°C as the results of low-temperature oxidation test. The amount of consumed oxygen for the bituminous and the semianthracite gradually increases wi th the reaction temperature, followed by a rapid increase at around 150°C. On the other hand, only a smalI amount of oxygen is consumed for EP dust. The result is supported by the DTA results indicating that the reactivity of EP ash is very low at the temperature lower than 400°C. Consequently, from the above results, the EP dust is not easy to cause spontaneous combustion troubles. 3.Bench-scale Testing The results obtained in the bench-scale co-firing tests are summarized in Table 5. In each case, flames were very stable including those from the secondary nozzle. 11 can be found from the S02 emission in co-f i ring is higher than in coal firing in proportion to the total sulfur input. N0X emission in co-firing, especially in case 3, is lower than that in coal firing. This result can not be explained by the ni trogen contain, so the other reasons must exist. Concerning to the unburnt carbon in fly ash, there is no particular difference among cases, though it seems to be smallest in case3. From the above results, the co-fi ring of EP dust wi th pulverized coal will be applicable for both cases of injection from the exclusive nozzle, and mixing |
