| OCR Text |
Show 4.3 Items Metered and the Sampling Locations . As shown in Figure 2, NOx, CO and O2 in the exhaust gas were metered con-tinuously at the following eight locations: above the drying, combustion and burnout grates, two at the primary combustion chamber exit, air-heater inlet, electrostatic precipitator inlet and exit( induced draft fan inlet), and the data was fed into the computer every 30 seconds for processing. When the dioxin content was measured, manual analyses were carried out at ESP inlet and exit in addition to the above continuous monitoring. 5 . Test Results 5.1 Normal (non-reburning) Operation Under normal operation, the entire preheated air stream is fed from underneath the grates. When the furnace temperature shoots up, cool air is supplied through the combustion chamber exit. O2 density at EP exit is 1 3%-1 5%, indicating an excess-air condition due to the air inflow of such sources as leaking from the air heater, air for EP insulator-protection, lime-injection air etc. Table 5 lists the operation data under normal operation. T a bl e 5 0 pera rInOg at a un de r No rma 10p era Ion Item Unit Ooeratina Data Remarks MSW Flow t/24h 69.6 MSW Heating Value kcal/kg 1,470 LHV Combustion Air Flow Nm3/h 15,400 Exhaust Gas Flow Nm3/h 19,900 Dry Gas O2 % Dry 14.9 IDF Inlet 5.2 Reburning Operation Furnace operation data with reburning system is shown on Table 6. There was little change in the heat generation, and no loss in the incineration volume. Under reburning operation, the primary air is kept at the minimum level needed for the combustion, and the secondary air enables the complete combustion of unburnt gas. On this test, we could reduce the oxygen content of the exhaust gas by 3-4%, and the volume of total exhaust gas was reduced despite the addition of natural gas. 6 |
