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 Units7.3 Dampers7.3.1 Power operated gas tight isolation dampers along with their drives shall beprovided at all locations required <strong>for</strong> carrying out internal repair andmaintenance <strong>of</strong> pulverizers, electrostatic precipitators and induced draft fanswhen the steam generator is on load. As a minimum following locations shallbe provided with power operated gas tight dampers/ gates:i) Guillotine gate typedampersii) Double multilouver/bi-plane type dampersa) In hot air duct at inlet to each mill.b) On each twin inlet and twin outlet <strong>of</strong> eachESP stream.c) Be<strong>for</strong>e and after each ID fan.d) At inlet to each <strong>of</strong> the regenerative airpre- heaters on flue gas side.e) At discharge <strong>of</strong> each <strong>of</strong> PA fan.f) At each economizer bypass duct(2x100%) (if provided).g) Interconnecting duct dampers asnecessary.a) Be<strong>for</strong>e and after each <strong>of</strong> the regenerativeair pre-heater & SCAPH on air side.b) At discharge <strong>of</strong> each <strong>of</strong> FD fan.7.3.2 Heavy duty multilouver dampers shall be provided at locations not requiringtight shut <strong>of</strong>f duty.7.3.3 Pneumatically or motor operated control dampers shall be provided at thefollowing locations and a minimum:i) Hot and cold air inlet to each mill.ii) At each air preheater outlet on flue gas path (if applicable).7.3.4 All dampers/ gates at ID fan discharge, primary and secondary APH outlets onair side, primary and secondary APH inlets on flue gas side and in hot airducts to mill inlet shall be provided with 2x100% pressurization fans toachieve 100% sealing efficiency. Alternatively, the above dampers can beprovided with sealing air from cold air bus duct suitably meeting therequirement <strong>of</strong> 100% sealing.7.3.5 The multilouver dampers shall be capable <strong>of</strong> effectively stopping the flowwhen in closed position and while in full open position shall cause minimumpressure drop. The isolating damper design shall provide positive shut<strong>of</strong>fwhen closed.7.3.6 All regulating dampers/vanes/blade pitch controls coming under autoregulation shall be able to provide the desired relationship between percentageopening and the flow.60
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