| OCR Text |
Show the last two viewing ports of the test boiler, and no "fireflies" were seen at the third and the last viewing ports prior to the stack. Figure 4-1 indicates the trend of the boiler thermocouple readings in order of increasing distance from the burner head. All thermocouples were located in the product gas stream, the first four in the furnace ceiling and the fifth and sixth in the furnace stack (Figure 3-2). The PETCOM flame profile closely approximates the behavior of No. 6 fuel oil. The temperature differentials between air and steam-atomized No. 6 fuel oil and PETCOM were about 100-150°F through the entire length of the test boiler. Although the PETCOM flame seemed to be lacking luminescence, its heat transfer efficiency to the furnace walls, as measured by the cooling water temperature differential, was comparable and in most cases slightly greater than No. 6 fuel oil, varying between 56 and 60 percent. This indicates that the PETCOM flame has higher emissivity due to petroleum coke particles. With air atomization, PETCOM combustion efficiencies of 95-100 percent were measured at excess air levels of 1.5 to 26 percent. The PETCOM flame was observed to be as stable as that of No. 6 fuel oil. With steam atomization, however, cooler flame temperatures were experienced with both No. 6 fuel oil and PETCOM. The heat transfer efficiency of both No. 6 fuel oil and PETCOM dropped to nearly 53 percent along with PETCOM combustion efficiencies of 84-87 percent. Overall, better performance was obtained from the FRC than the modified NA nozzle. As illustrated in Figure 4-2 with air and steam atomization, sulfur dioxide emissions for No. 6 fuel oil and PETCOM were close to theoretical calculations. PETCOM emits more SO because of the higher sulfur x coke. PETCOM also shows a 100 PPM NO increase over oil NO emissions X X primarily due to the higher nitrogen levels in the petroleum coke. Steam-atomized PETCOM shows predictably higher SO levels, but lower NO levels, an actual drop of 110 PPM which was influenced by steam-induced lower flame temperatures. 19-15 |
