Standard Technical Features of BTG System for Supercritical 660 ...

Standard Technical Features of BTG System for Supercritical 660/800 MW Thermal Unitsii)Flame monitoring system shall be fail safe and easily maintainablewhich shall include flame detectors of proven design for the type offuel, environmental condition and other conditions, of establishedreliability at all loads of the steam generator. It shall be designed towork under all adverse conditions such as wide variation in fuel/airinput ratio, wide variation in fuel characteristics, variation in operatingtemperature, maximum temperature under interruption of cooling airsupply. The system shall conform to NFPA recommendation andlocation of detectors as per NEC requirements.iii) Flame detectors shall be working on the dynamic and static propertiesof primary combustion zone of each type of fuel and flicker frequencyof flame. It shall pick up only the flame to which it is assigned andshall not respond to the adjacent and background flame or otherradiations generated in the furnace. The design shall also take intoaccount the absorption by a coal shroud, recirculated dust or otherdeposition on the flame detector head. The complete system shallprovide the discrimination between oil and coal flame. Intensityindicators for main flame shall be provided alongwith galvanicallyisolated 4-20 mA DC signals and hooked to SG DDCMIS.iv)The system shall be easily maintainable and include automatic self testfacility at regular interval.v) A portable flame detector testing kit shall be provided with built instabiliser, capable of simulating both oil and coal flame, and testing offlame detector head unit at field. The testing kit shall also have facilityfor testing all type of electronic cards as being used in the flamemonitoring system.vi) In case of tangentially fired boiler, the flame detectors shall bearranged in such a manner that coal flame detectors are available foreach coal burner of both above and below each coal burner andseparate oil flame detectors shall be provided for each oil burner. Incase of discriminating type flame detectors capable of detecting anddiscriminating both oil and coal flame, with the help of a singlescanner, the same can also be utilised for monitoring both oil and coalflame. For any other type of firing i.e. non-tangential type the flamedetectors shall be provided for each coal and oil burner respondingonly to the flame of its associated burner.vii) 2x100% scanner air fans, one AC operated and other DC operated,shall be provided to supply cooling air for the flame detectors.17.3.2 Coal feeders control and instrumentationi) Coal feeders shall be provided with microprocessor based C&I systempreferably using same family of hardware as that of DDCMIS.162