| OCR Text |
Show somewhat (about 10 percent) higher NO emission found for EDS was probably attributable to its lower hydrogen content. Figures 8 and 9 depict FBN conversion efficiencies at full load and at low load conditions. Results in Figure 8 are presented in the form of a bar chart. The lower portion of each of the left bars represents the base diesel fuel NO emissions, arbitrarily set as 100 percent. Superimposed in the upper segment are the calculated incremental NO emissions which potentially could occur if all the FBN present in the given fuel were converted to NO . The bar on the right side represents the actually measured NO A A emission with the respective fuel. A comparison of the heights of the left and right bars offers an indication to what extent the conversion has proceeded. In the case of EDS and shale oil, only a very small fraction of the FBN was converted into NO , if at all. Whereas, when PFO was burnt, the measured NO vastly exceeded the amount of NO potentially available from FBN; thus the increase was mainly of thermal origin. From these results, the overall conclusion was reached that in the high load region, where the fuel to air equivalence ratios were the highest, the contribution of FBN to the total NO emission was at a minimum. However, for low load conditions shown in Figure 9, presented as the prevailing total fuel to air equivalence ratio in the combustor, a different picture has emerged. Here, a noticeable FBN conversion was found, probably due to the increase in oxygen availability. It is interesting to note that the results of an earlier test series with FBN doped diesel fuel agreed reasonably well with the current data. NO emissions for EDS shown in the J x graph were reduced by 10 percent to compensate for the increased thermal NO formation caused by the lower hydrogen content of the fuel, as mentioned earlier. Other Emissions The ranges of C0,N02,UHC emissions are shown in Figure 10 and PNA emissions (polynuclear aromatics) in Figure 11. These appeared to be non-specific to the fuels and generally low, especially in the higher turbine load area. Soot, smoke, and particulates emissions followed the same trend as presented 1.4.9 |
