Document 5kkMe992azkndZQ9rLgXeGNY8

form a well-balanced power-generating system. Steam Turbine. The new Cenerel Electric 25,000-kw 3600-rpm turbine, de signed (or 850 psig. 900 F, drive* e hydrogen-cooled generator. Steam to the turbine passes through an emer gency atop valve to two control voire cheats mounted on the upper and lower halves of the High-pressure shell. From here ten control valves distribute steam to the turbine nozzles. The 19-atage qingle-flow turbine extracts steam from the fourth, ninth, thirteenth and seventoemh stages for feed-water heating. ' The turbine-control system operates hydraulically by oil pressure furnished by the main motor-driven pumps as- s'embled in the oil tank, Either of two pumps are used normally and when hydroulic-pump pressure fails a steam* driven auxiliary pump automatically comes tnto<service. Chrome-iron alloy wos.chosen for the turbine buckets to resist corrosion end erosion by steam. Stellite shields fas tened to the outer portions of the lost- stage buckets provide on additional safeguard against erosion. Main Generator. Capacity of the 25.- 000-kw (lOft-pf generator operating at 12,500 v dan be increased about 15ft by raising the hydrogen pressure from 04> to 15 psig. Four hydrogen coolers mounted in the generator casing ore so arranged that any one of them may be removed for cleaning while the ma chine remains in operation. The main and pilot exciters are direct connected. Meta Condenser. A 35,000-gpm cir culating-water pump takes water from (he upstream side of a dam across the Kock Hirer and forces it through the 2-poso surface condenser. The con denser has 4770 Admiralty-meia] 1-in. dla tubes with 20 feet effective length NSW PLANT EXTENSION obut* original building at loft with machine shop of upper left partly shown. Second h-p unit will be housed in extension to right providing a total cooling surface of 25,000 sq ft. The condenser outlet dis charges downstream from the intake, and sheet metal piling directs this water to a small hydro unit. When the flow in the Hock River drops to a point that does not permit operating the hydro unit, the piling causea the discharge water to spread over a large area. The river water varies from 32 to 90 F. A twin-element 2-atage air ejector furnished with inter- and ofter-coolers removes the noncondensable gas. Con densate collects in a 2000-gal storage- type hotwell from which 2-atage .con densate pumps pass it successively through the air-ejector coolers, drain cooler. No. 1 heater, vent condenser and deaerating heater. Steam Generator. Pulverized coal fires the single 275,000-lb-per-hr in tegral-furnace type Babcock & Wilcox steam generator. The outside furnace shlowall, roof, hopper, furnace rear wall and inside or baffle wall are closely spaced bare tube construction using 3-in. tubes on 3-in. centers. All of the outside waits of bore-tube construction ore plastered on the exterior side with one inch of baffle type concrete mix, reinforced. with expanded metal fol lowed by asbestos block insulation and a steel cosing. The burners mount horizontally In the front wall of the furnace. The wall tubes bend to'form an annular opening through which the coal and air pass on their way into the furnace. Each burner assembly consists essentially of a pri mary nozzle, inlet elbow, directions! vane, secondary air damper and burner nose tile. A steam-atocniiiaf cH-bumfng element installed through the inlet elbow and primary nozzlo lights-off tbs pulverized coal. The directional rtae causea turbulence io the burner throat An impeller mounted on the end of the oil-burning element makes it possible to maintain the best possible turbulw for varying loads. The secondary-*** damper, of the register type, controls the quantity of secondary air to the In dividual burners and shuts off tbs 1* supply if ony burners are out ol serviceTwo DAW pulverizers serve the bollef and use the ball-grinding principle *** spring loading of the grinding elewentt, One row of bolls rides between * **' M ()) .POWER *" tionaiy top grinding ring ond a' bottom grinding ring driven by a 200-hp in. duction motor. The totally enclosed driving gears run in a both ol oil. Air from a 100-hp motor-driven blower enters a windbox surrounding the lower part of the grinding chamber. After passing through a throat region, the air picks up the pulverized Mate rial which haa passed through the balls and lifts it to the top ol the pulverizer. The classifier separates the coarser coal particles end rejects them to the grind ing zone (or further pulverization. Pow dered coo) of the desired fineness then passes to the burners with the air stream. A 26-in. diameter table-type feeder mounted on each pulverizer regulatea aMT SICTON A-A shows arrangement of boiler, pulverlxers, bunker, cool scales, Motor, pumps, turbine, moln condenser ond circuiting water discharge the incoming coal flow. The feeder controller automatically maintains the correct fuel:sir ratio over the entire operating range of the pulverizer and also maintains proper burner line veloci ties at low loads and proper fineness at high output. Since the regulation of pulverizer output Is accomplished by changing the air .flow to the pul verizer the required change in the fuel feed is automatically regulated by the pulverizer-feeder controller. In this way the combustion control system regu lates the fuel feed by varying the pri mary air. -The master controller of the auto matic combustion control system re ceives air-loading impulses front the steam pressure element, and then dis* -patches corresponding air loading pres sures to each fuel and air regulator on the boiler. At the master controller, KANT SECTION B-B (toe plan view) shows location of air heater, f<J and 1-d the air pressure dispatched to the ven bn, dust collector ot left; hooters end evaporator, center; turbine room, right ous regulators can be controlled either fUlVEBlZED.COAL BURNERS ond secondary air box for fir"O.ihe 275,000-lb-per-hr boiler ute fuel oil for Ignition POWER Jun* (MB HEAT-6ALANCE DIAGRAM shows steom conditions for unit carryfrqj 25,158-kw (ood of f f,fl06 flw per tewhr ratal hoot mto ()) 67