OCR Text |
Show It is considered that in the former, high NO emis- ' x sion occurred at the air-rich portion due to uneven mixing of the gas and air in the circumferential direction, while in the latter, NO emission occurred due to rapid combustion caused by the rise in the initial mixing rate of the gas and air. Concerning with uneven mixing occurred in the circumferential direction, it is confirmed that particularly when eccentric installation of the burner caused high NO emission. * x 4.3 Influence of Inner Tube Length L~ An important factor for determining the performance of KS-2 Burner is the length of the primary combustion zone, because it gives uniform combustion in the length direction of the radiant tube. Within the range of L- < 200 mm, NO emission increased, as the inner pipe length L? is reduced, and within the range of L^ 250 mm, NO is saturated at the lower level. Influences of various factors on NO emission were x explained above, and in the burner under the optimum conditions shown in Table 1, a NO emission lowering effect of more than 35% was obtained compared with the NO emis-sion level of ordinary burners. 1.9.9 |