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Show When analyzing behavior of flue gas fluctuations, w e deal with very low frequencies. This makes the application of traditional data analysis techniques difficult. In the n e w M P V Combustion Diagnostics Systems, w e developed specialized computer processing techniques and a new set of signal processing algorithms9. The MPV-1 system receives inputs from optical sensors in the upper furnace and presents information to the operator in bargraph and trend form. The M P V optical sensors require no cooling air, no power supply, no extraction nor sampling and are virtually maintenance-free. The first MPV-1 system has been in operation on Homer City Unit 3 since August 1997. Based on positive results, the plant installed similar systems on Units 1 and 2. The purpose of this project was to demonstrate that the new M P V - 1 system provides consistent, sensible and repeatable response to changes in combustion conditions, correlates with measured LOI values and can enhance boiler performance and reduce N O x , C O and LOI emissions. Equipment Homer City Generating Station (HC) has 3 power units. Units 1 and 2 (620MW each) are equipped with Foster-Wheeler (F-W) boilers. Each boiler has 24 opposed wall-fired low-NOx burners, 6 groups by 4 burners in 3 elevations with a c o m m o n non-compartmentalized windbox. Unit 3 ( 6 5 0 M W ) is equipped with a Babcock-Wilcox ( B & W ) boiler with 48 dual register low-NOx opposed wall-fired burners, 6 groups by 8 burners in 3 elevations. Unit 3 has a compartmentalized windbox, which allows individual adjustment and biasing of secondary air (SA) flow to each burner row. Both units are equipped with an overfire air (OFA) system for N O x reduction. Both F-W and B & W burners have 3 secondary air adjustments each. Each burner is equipped with 2 flame scanners that are positioned for detection of main and ignition flames. Each boiler is equipped with several in-situ 0 2 probes in the convective pass after economizer. Other gas analyzers (CO, N O x and opacity) are included in the C E M system. LOI is measured periodically by collecting flyash and bottom ash samples. MPV-1 Combustion Diagnostic System The MPV-1 system receives inputs from a bank of several optical sensors mounted in the boiler front observation ports in the furnace exit area (Fig. 2). These signals are connected to a data acquisition card in the M P V computer in the Unit Control Room. After signal processing and algorithm calculations, the resulting parameters are presented to the operator in bargraph and trend form to characterize the distribution profiles of products of incomplete combustion and flue gas temperatures across the width of the furnace (Fig. 3). The optical sensor is mounted in a special mounting box which protects the sensor from pressure excursions and enables continuous long-term operation without supply of cooling air. The M P V sensors require no extraction, no power supply, and are virtually maintenance-free. Terminal Box oooooooo Terminal Box i-O i-O i-O rO MPV-I L_(~) Sensors "-0 L-o L-o D/A Terminal Box MPV-1 Computer "^A*CardJ Figure 2 M P V - 1 schematic diagram 3 |
