The high restrictions in environmental requirements have led to modifications of the both coal type and firing mode. In order to prevent a different faults in boiler operation and as a result a reliability reduction, special monitoring and diagnostic techniques is required for engineering analysis and utility production management. In this sense an on-line supervision system FURNACE have developed and implemented for 575, 550, 360 Mw coal fired units. The developed system provides on-line information regards furnace performance, including fireball location, furnace exit temperature increase that indicates the necessity of activate furnace sootblowers to control steam temperatures and prevent excessive accumulations of slag and heat surfaces tube overheating. However, the FURNACE system can not provide flue gas temperature distribution near the burner zone and it leads to limitation of the possibility of furnace fine tuning for the aim of NOx reduction. Due to this reason new diagnostic system ORFEUS was installed in power plant. The ORFEUS is a system for continuous visual monitoring of high temperature processes with a sensor lance. A high quality picture with wide angle of view and a small sensor diameter is achieved using a boroskope as lens. With this technology the CCD camera can be mounted in the cold part of the lance. This way sensitive equipment is mounted outside the combustion chamber, allowing continuous use with high process temperatures. The pictures coming from the sensor can be viewed and analyzed directly in the control room. In order to evaluate capability of both system combined application series of tests with different operation were conducted on the boiler. The testing was primarily focused on quantifying the impact of overfire air (OFA), excess air, primary air flow and unit loads on boiler, furnace, pulverizers performance, NOx and unburned carbon loss etc. The evaluation was performed for 575 MW units equipped with tangentially fired boilers designed by Combustion Engineering. The on-line information obtained from both FURNACE and ORFEUS systems is allowed us to perform fine tuning of the firing system in order to optimize combustion process. Based on performed work may be concluded that combination of both system is able us to receive detail information of furnace performance in real time including flame position in the initial burner zone. As result it was achieved additional NOx reduction by 10–15% at unit full load and by 20–35% at partial load without any impact on boiler performance, efficiency and reliability.

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