| OCR Text |
Show 3 (2) Applied Experiment After deciding specifications for the burner, we have confirmed the combustibility by changing the exhaust gas composition with 350 - 600°C and 14 - 17% (wet) of 02 as shown in Fig 5. Quantity of the gas turbine exhaust is set up with 4,800 Nm3/H (wet) in case of 15% of 0 2 to have the maximum burner firing rate 2,800 kW. At the same time, we have added steam into the gas turbine exhaust and confirmed that the cornbustibili ty against change of H20 rate in the exhaust gas. This is done because the gas turbine normally performs the injection operation with water or steam for NOx reduction. Only NOx emission by the exhaust supplementary firing burner is calculated by below expression and evaluated for the performance. At this experiment, NOx level of gas turbine exhaust was 70 - 170 ppm (02 = 0%) as well as real gas turbine exhaust. NOx (ppm, 02 0%) a a = No (ppm, 0 2 = 0%): NOx after the exhaust supplementary firing Nt (ppm, 0 2 = 0%): NOx of the gas turbine exhaust Xb (kW): Firing rate of the exhaust supplementary firing burner Xt (kW): Firing rate of the gas turbine exhaust generating burner 3. Elementary Experiment Result and Discussion 3-1 Swirler Shape In Fig. 6, relationship between first swirler intensity and NOx emission is shown. In case that the outer diameter is 228 0, NOx emission became lower than 50 ppm when the number of wing decreased from 12 to 8 pcs. or the swirler intensity is decreased. If we make the outer diameter of first swirler smaller, firing becomes unstable. Therefore, we selected 228 0 which is the maximum size installable to first stage and made the number of wing ten pcs. For second swirler, NOx emission at its unexisting is rather lower than at existing. Otherside the firing became unstable at maximum burner Load. As we assume that it is because the swirling intensity is too week hold the flame stable. We have decided to set up second swirler. 3-2 Gas Nozzle Shape We have examined that the effect on NOx emission for the number of gas nozzle hole (6, 8) and angle (70 - 100°). 6 gas nozzle hole shows lower NOx emission than 8. Fig. 7 and 8 show effect on NOx and CO of the nozzle angle which is 80° and 90° with which the firing was stable. NOx emission is lower when the nozzle angle is 90° than 80° and becomes lower than 50 ppm. It is thought that heat-spot is not made because the flame becomes wider with the gas nozzle angle of 90°. On the other hand, under |
