Standard Technical Features of BTG System for Supercritical 660 ...
Standard Technical Features of BTG System for Supercritical 660 ...
Standard Technical Features of BTG System for Supercritical 660 ...
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<strong>Standard</strong> <strong>Technical</strong> <strong>Features</strong> <strong>of</strong> <strong>BTG</strong> <strong>System</strong> <strong>for</strong> <strong>Supercritical</strong> <strong>660</strong>/800 MW Thermal Unitsii) The system resistance curves shall always be sufficiently below the fanstall line.iii) Best efficiency point shall be close to 100% TMCR operating point <strong>of</strong> fan.8.8.4 Fan control systemi) Fan flow control shall be by blade pitch control. The final control elementshall be electrically/ pneumatically operated.ii) The system shall be capable <strong>of</strong> working on automatic mode <strong>for</strong> all regimes<strong>of</strong> operation in a steady and stable manner.8.8.5 Primary air flow measurementPrimary air flow measuring devices as per OEM’s proven design shall beprovided at air inlet to each mill as well as at the suction <strong>of</strong> each fan. PA faninlet flow measurement shall be provided using fan inlet elbow. However, ifsuch an arrangement is not possible, flow element (venturi/ aer<strong>of</strong>oil system)shall be provided with three pair <strong>of</strong> tapping points at suction <strong>of</strong> each PA fan.Necessary tapping points <strong>for</strong> temperature compensation in the flowmeasurement shall also be provided.8.8.6 Material <strong>of</strong> constructioni) Fan blades High strength Aluminium alloy withminimum hardness <strong>of</strong> BHN-75.ii) Base plate Base plate - cast iron or welded steel.iii) Casing Sheet steel <strong>of</strong> suitable thickness.iv)Fan inlet box, diffuser &intermediate pieces8.8.7 Fan bearing lubrication systemSheet steel <strong>of</strong> thickness not less than6.00 mm.i) The rotor assembly shall be supported over an oil lubricated bearingassembly consisting <strong>of</strong> antifriction/sleeve bearing adequately sized to takecare <strong>of</strong> radial thrust loads.ii) For mounting <strong>of</strong> vibration pads/ pickups, flat surfaces shall be providedboth in X and Y directions, on the bearing housing.iii) In case <strong>of</strong> oil lubricated bearing the design shall be such that bearing arelubricated by external oil lubricating system in which oil is cooled byexternal cooler.iv) Duplex RTDs (100 ohm at 0 0 C) and temperature indicators shall beprovided <strong>for</strong> each bearing as per standard practice <strong>of</strong> the OEM <strong>for</strong> local aswell as remote monitoring <strong>of</strong> bearing metal temperature.72
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