Document Oz6j0odkyqybGvgK0vQ0zp18j

i-mm m )V. m wz FOUR OF THESE STEAM GENERATq! THOUGH FOUR MILIS SUPPIT lhCM .l0ht bum.r. OO bolter No. 2, only three nulls ore needed to develop rated output TWO-DRUM OPEN.PASS BOILER fired with pulvertxad cctf |('!HAH Of STATION LAYOUT SHOWS circulating woter intoko ot ond of plr on nos ottemparotvr located In lower drum for superheat contnf< J>r *ifw ond the discharge tunnel ot right angles leading Into slip next to stotlon bine for repoirt without disturbing the rest of the unit system. The h-p end I p elements of the main turbine cannot be operated separately. Auxiliary steam taken from the boiler drums avoids the need for de superheating. Pressure reduces to 400 psig for the auxiliary oil pumps and air ejectors, end to 125 psig for the heattag-system headers. Bleed steam comes from two points in each of the h-p and 1-p turbines, the lower point on the h?p element be ing at crossover pressure. Makeup System. Gty woter sup plies the makeup system. Two lines from separate sections of the city mains and o 24,000-gal storage pH insure rea sonable reliability. Water is pumped from the pit through icolile softeners and blow-down heat exchanger into the makeup deaerator. From the deaerator the evaporator pumps deliver the water to the evaporator ihelL Normally vapor from the evaporator condenses in the evaporator condensers, in the heater rows between the 2nd and 3rd heaters. Evaporator vapor alto supplies the makeup deaerator. With the main unit out of service, auxiliary steam produces evaporation, the vapor condensing in the auxiliary condenser, and the con denser drains pass to the condensatepump suction. Cooing.Wafer System. This system hat two parts: (l) supply by the gen erator cooling-water pumps and (2) supply from the liver-water pumps. The former feed the generator coolers and the turbine-oil coolers, and the Utter the rest of the system. Rotary strainers, at the pump discharges, strain all cool ing water. Using two sets of pumps saves power because of the much lower head requirement! on the generator cooling pumps than on the river-water pumps. Cifculatloj-Wotc* System. Two 76;- 000-gpm circulating-water pumps serve each main unit condenser. Each ptunp, in separate sections of the screening basin at the river front, obtains water fM through one revolving screes end djjjj the tubes paralleling main turbine charges through a butterfly valve tobi a 6-it 6An. die precast concrete p/p?j iF^emter lines because of the space l^attded (or pulling tubes. Rupture line delivering water to the condense^ jfrjdtiks provide atmospheric relief to the Automatic control opens and closes thy Vjhw exhaust stack. butterfly valves with starting and itojjJ Generators. Two Babcock & ping of Use pumps. fif'dcox boilers supply each turblna-gen- Two pipes, each 6-ft 6-ln. die, jerrior. They are 2-drum open-past installed Instead of one larger plp*bwl ^ .Jvrt-bowoffl type having a design pres* Er;'.'t|ra of 1075 prig and producing steam cause small depth from yard level W- pier decking would permit oolhhdl 850,000 lb per hr &$$? ^ continuously. ot 925 prig and The 3-hr rating larger. Also, this alio la aotisfstt^Tfl EggMSJW lb per hr. Each boiler has for one-pump operation. jw An adjustable weir at the condenser LY^^WSaq-lt continuous-tube econom- discharge prevents breaking the , R^^hsaste3r5,,9a2J-1rq1.2fr5-cooqn-fttinuaottuesm-tpuebreetsoar,- at low tide. Baffling at dUchargotne^jj nel exit dissipates strong currents iW, ^*500-aiq-ft regenerative-typo air might Interfere with boat handling end four B&W type E mills, that ores. W IMP high-grindability coal three mills be adequate for the rated steam Chlorine, obtained in bulk vis rs$j road tank cars, treats both eireulaOTji a( ona boiler. water and cooling-water systems sHemperttor, in the lower drum, f.l4^ltttanj temperature to a maximum screening basin. v*-'* ^ Condensers. These units ere Wheeler, surface typo, single pari ^ *tje**10 Steam P&>rin6 from the second section of the super- deaerating hot wells. They are flows through a 3-way valve, which odmita the needed amount to the atiemperator and bypasses the ' re mainder. The boiler outer wolls are enclosed in full plastic casing, a considerable amount of the insulation being gunited in place. Provisions have been made (or aeid woshing, and* all boilers are being treated before going into service. Tube turbining afier completion of the boil ers Is considered unnecessary. Retractable soot blowers serve the boiler, and rotary blowers are used-on the economiser. Every boiler has two forced- and two induced-draft fans. Each fan has ahydraulic coupling to provide variable speed. One stack serves each boiler. A venturi throat at each stack top improves dissipation of gases and pre vents down-drag on tbo leeward side. Cm! Handling. Coal U normally delivered via barge and In emergencies via rail. Specd-o-matic cranes unload ft from barges, feed it by apron feeders to Bradford breakers in the coal tower, from here belts transport it to the bunkers, passing over o magnetic separ ator at the boiler-house entrance. Two complete lines of equipment are each capable of handling 350 tons per hr. One 1000-ton bunker fed by either of the mein cross belts serves each boiler. An inverted U-shaped corrugated iron hood covers the Inclined belt conveyor. The entire cool system inside the build ing is encased and the bunkers sealed against dust leakoge into the building. For bunker ventilation, air enters through one-way louvers and is drawn out by the induced-draft system. In the emergency handling system, coal can be unloaded from four 70-ton cars simultaneously. It passes from the unloading hoppers by apron feed ers. flight conveyors and gravity-dis charge elevator and conveyor through a granulator just ahead of the elevator. A central control panel for the eoalhandling system is located on the con veyor floor of the boilerhouse near the transfer chutes at the No. 1 unit bunk ers. A private telephone system con nects control panel, crane and yardmaster's office. Afh Handling. A recirculating type of ash-sluice system removes ash from' the boilers. Water recirculates from the ctearwell at the end of the system,. Ash sluices from the boilers, through trenches to the ash pump pit where it posses through clinker grinders before reaching the pumps. . The pumps dis charge to a pit in the yard from which a locomotive crane removes the ash and the water decants off to the clearwell. Trench liners ore mostly of Ashcolite, but in one section granite blocks have been used as lining for experimental purposes. A multicyclone-type mechanical col lector, between air heaters and induceddraft fans, removes flyaah. From here a fan transports the ash to drop-out and storage tanks; when finally passing through unloading valves, it U commerciolly conditioned with water for disposal. Model Tern. Many model tests and studies 'determined design and materi als. Core borings and chemical tests were made on the soil- Different types of bearing piles were driven and test loaded before preparing specifications. Arrangement of baffles at (be discharge tunnel exit, blading for circulatingwater pumps, shape of screening basin at circulating-pump suctions, condenser water-box design, arrangement of burn ers, windbox design, and material for condenser tubes and other tubes com ing in contact with river water were 64 (I36j POWER Msrch Iff M.rd, l,,J (1)7) 67 < r; mm