| OCR Text |
Show interaction by affecting both the distance and the mixing processes of the two jets. None of the data currently available provides a basis for predicting these effects. To examine the two phenomena discussed above, an experiment with two interacting flames will be conducted. Figure 9 shows a schematic of the experimental variables to be considered. A modification of the single burner extension of the furnace will provide for an evaluation of the effects of distance and angle for selected burner configurations. The results of these two well-characterized experiments will be used to design concepts for testing in the tangential model of the EPA furnace. Heavy Liquid Fuels The experience in pilot scale development of staged combustion and advanced burner design indicates that it is more difficult to achieve high percentage reduction of N0X for heavy liquid fuels than for coal. Some evidence exists to indicate that the difficulties may arise from differences in the way that the nitrogen is bound in the fuel and, therefore, the reaction history of the fuel nitrogen intermediates. More refractory nitrogen in the petroleum derived residual fuel oils may be released later in the combustion processes when more oxygen is available for conversion to NO^. The synthetic liquids derived from coal and shale not only have larger amounts of nitrogen but also have the nitrogen distributed over the full boiling range of the crude. In addition, major limits on N0X control for petroleum residual fuel oils is the onset of carbonaceous particulate (smoke) formation as the primary zone becomes fuel rich. Since the formation of carbonaceous particulate is related to the carbon-hydrogen ratio of the fuel, this limitation may become more severe for synthetic liquids derived from coal. A fuel screening experiment is in progress in an attempt to quantify the effects of fuel composition on both N0X and carbon particulate emissions. A small furnace similar to the one shown in Figure 6 is used. The fuel is introduced through a sonic atomizer which produces a relatively narrow cut of small droplets (20 Wn). The droplets are well dispersed in the combustion air 3-31 31 |
