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Show 55-GAL DRUM OR TANKER TRUCK PULVERIZED COAL (OR OTHER FUEL) SUPPL Y SYSTEM PART OF PHASE II WORK TRANSFER PUMP .... TANK HEATER COMBUSTION COOLING SYSTEM RIVER WATER RETURN STACK , 'r 'f"rt ri'::~t'['1Fifl~fir~ l COMBUSTION I J AFTERBURNER CHAMBER LLLU. I I r "" "JldJ':r";" -~"FmJJ WET SCRUBBER DRAIN DRAIN SUPPLY HEADER' \ FLOW ~ G METER GAS OXYGEN 1 I CITY WATER Fig. 2 - Schematic of MIT-CRF and Support Systems PERFORMANCE TESTS The objective of the performance tests was to determine if the four wavelengths selected for the SFA provided the expected signals from typical burner flames. Two tests were carried out, one with the coal-water slurry (CWS) fuel and another with the gas fuel. The fuel-air ratio was changed for each fuel and data were recorded. The ideal location for the SFA unit on the furnace is behind the burner, so that it views the flame in the axial direction. Axial positioning also minimizes signal fluctuations due to variations in the flame position caused by firing rate, airflow rate, and other operating conditions. Also, the UV emission originates from OH and CH radicals that are formed early in the combustion process and, thus, these emissions are from the base of the flame. The IR emission of excited C02' on the other hand, originates from later combustion processes further into the flame. The MIT-CRF design did not readily allow viewing of the flame in an axial direction. Since these tests were carried out in conjunction with the ongoing combustion tests with CWS fuel, no modifications were made in the furnace front and measurements were made by the SFA positioned to view across the flame. The SFA was moved to ensure that optimum UV and IR signals were being measured. The SFA optical unit was mounted on a track mechanism and moved along the flame length. Data were obtained for each set of operating conditions for 20-inch intervaJ.s along the flame, for a total length of 25 ft. At each location, the four wavelength signals were recorded using a Digital Equipment Corporation MINC computer data 224 acquisition system. Signal magnitude was obtained by using the front panel display on the SFA electronics box. TEST RESULTS Data were obtained for firing natural gas and coal-water slurry fuels in the CRF. The main parameter of interest for the test program was excess air, which is an indicator of the airfuel ratio. Table 1 lists the conditions for which test data were collected. For all five runs (two with natural gas and three with coalwater slurry fuel), the SFA was moved along the flame, and data were recorded by the computerized system. Table 1 - Test Conditions Fuel Ox(yPgeenr cLenevt)e l Run No. Natural Gas 1 Gl, G2 Natural Gas 3 G3, G4, GS Coal-Water Slurry 2 Cl, C2 Coal-Water Slurry 5-6 cs Coal-Water Slurry 7-8 C6 GAS FIRING Figures 3 and 4 show the ratio of the two UV channels (OHjCH) and the two IR channels (IRj ref), plotted against the distance from the burner for gas-firing at 1 percent excess oxygen |