OCR Text |
Show 4. Combustion Test with Multi-Burner Furnace 4.1 Experimental Figure 9 shows the profile of the Multi-Burner Test Furnace. The burners used were almost the same as the one already described in Figure 5. The furnace adopted the opposite combustion system composed of front and rear burner pannels with three burners each lined up vertically, being six burners in all. As the amount of coal supplied was 25kg/h per burner, about 150kg/h of coal was able to be burned simultaneously with the six burn-ers in the furnace. Further, an after air port supplying only air was provided each burner pannel in the upper portion of the burners. Four particle sizes described in chapter 2 for each of three coals, A, Band D listed In Table 1 were tested. The tests were perfor.ed under two types of conditions. One varied the furnace exit ' O2 concentration by adjusting the a.ount of a(r from the air port at the constant air ratio of burner (SR) of 0.9. The other fixe~ O2 concentration at the furnace exit to be 3% and varied the air ratio of burner froll 0.8 to 1. 1. 4.2 Results and Considerations Figure 10 shows the effects of excess 0, on NOx, UB and BR for coal D. When the excess O2 was lowered, NOx was hardlr changed (at the constant SR ) whereas UB was greatly changed ( BR was lower) at every size of particle. Figure 11 shows the effects of air ratio at the burner zone (SR) on NOx. UB and BR for coal D. NOx was increased drastically with increasing SR. -7- . N ExJI<.lllsl F jg. 9 Multi Burner Test Furnace 400.--------..-------- I D Coal I SR=O.9 ~ 200 e IIZUUif Oo~ --1~.0- --2-.0~ --3.~0 ~--4.~0 ~ 20~---~,----,-----,----~,--~ • 100 15 • o *~-<> ~ .~~ , 0 ,,"~ / 99 10 ~ .. () 8R ~ <:"j ',.~ CiI)'" • 98 5 • "', .... (t ...... ...... ""-.0 un' • 91 0 I . I • 0 1.0 2.0 3.0 4.0 Excess 02. ex.02 (%) F ig.l0 Effect oJ Excess 02 E 0:::: co |