Document V3jMNGL85a76ay0qdVzqkbNdZ

i; PLANT HAGOOD houses all equipment except deaerating heater and NO WALL separates turbine-generator, right, and oilstorage tank (on roof). Induced ventilating scheme draws air through fired boiler, center back. Control board of turbine first-floor windows and basement areaways, discharging through roof backs onto that of boiler, centralizing supervision. Plant Hagood Meets Growin; LXf LX on / Circulating - conditioner 1 water pumps / Tvrbine-oif storage ------- -------- ---------------------------------------/-----------------1 tank Sump pump CROSS SECTION OF STATION shows simple arrangement of equ>c --Os 1 -fired boiler can be quic'vly converted to gas. 82 Note ample space provided for possible future coal-handling ond firing equipment. Operators need not go above first floor RS-000172 1/17/02 NUECES POWER 1940 fuel-pump plunger motion dies out. Bringing controT^peeltfLfifth position causes a small air-pri&Sijpe pis~ ~ ton to return pistons to outer dead-tcenter and air is expelled from cushion chambers. After returning control wheel to position 0, starting operation may be repeated. It is possible to start and stop thpAinit in 20 seconds. STABILIZER ACTION. An important function still remains: Mean pressure of air-cushion chambers must be ad justed in accordance with prevailing /orking pressure (supercharging pres Air from starting bottle---*-y STARTING SYSTEM: Unit is started by introducing air under pressure to cushion chambers. Control insures simultaneous admission of right amount at proper pressure sure or pressure before the turbine). When working pressure changes, aircushion mean pressure must be altered in the same proportion, to hold proper compression pressure in the engine cyl inder. The stabilizer does this auto matically. Mean pressure in the air cushions is automatically adjusted to pressure in the engine case, which is it function of engine load. But while Pressure in the engine case, that is, of the scavenging air, may be assumed^ constant for any given load, air in l ie cushion cylinders is compressed a^every stroke and al lowed to expand again. Thus it is at times above efigine-case pressure, and sometimes b/low. Consequently, during one part of the stroke, air may flow from engine case to cushi/n space, with return flow dur ing the other part of the stroke. For this purpose a passage is provided be tween the engine case and the pipe connecting the air-cushion chambers. By introducing 'a backpressure valve and a controlling slide valve, this pas sage may be kept open until desired pressure balance between engine case and air cushions is maintained. Stabi lizer diagram shows t(iis arrangement and position of slide v^lve during ad STABILIZER: Backpressure valves and controlling slide valve coordinate/mean pressure in air-cushion spaces with supercharging pressure at various engine loads mission and expulsion periods. Stabilizer may be built, as a single backpressure valve incorporated in a movable slide valve. Most suitable back mg any rotational movement of the pis and previously mentioned guiding pipe pressure valve is the type usually em ployed for compressors, with a cross tons. Arrangement for cooling the en gine pistons requires only a single stuffing box at each end. The air-cushion between the two air-cushion chambers. STARTING PROCEDURE: Putting the control wheel in first position delivers section of ample dimensions. The valve is operated by a spring-loaded stepped plunger, by which any desired linear space reaches deep into the interior of air at a preselected pressure to a small regulation of pressure from air-cushion the engine piston. receiver, air pressure in the receiver level to engine-case level may be ob Admitting pressure air to the cushion holding a disk valve closed. At posi tained. spaces throws the pistons from their tion 2, air pressure on top of a control FUEL INJECTION. In (ree-piston en outer position toward inner dead cen plunger integral with the disk valve is gines. fuel-injection must meet special ter. Because of the large piston area, released, admitting air from the re conditions. Fuel must be injected dur air pressure need not be high. Starting ceiver to the cushion chambers. Bring ing a period that includes the inner system must, however, provide for sup ing control wheel to the third position dead-center position of the pistons, plying right amount of air. at proper closes the air-delivery pipe, pressure of when there is no motion. It thus be pressure, to both chambers simultane air above the plunger closes the disk comes necessary to operate on a svstem ously. Starting-system diagram shows valve and the small receiver fills again. of accumulation. I ucl must be metered the connection from starting apparatus At position 4. air pressure lifts the {Continued on page 1561 POWER January 1949 RS-000173 1/17/02 NUECES 81 TURBINE-GENERATOR, 22,500 kw,uses 850-psig 900-Fthrottle steam, exhausts to condenser at 2-in. Hg obs backpress. Three bleed points supply one deaerating and two closed heaters MAIN CONDENSER with 20,350 sq ft heat-transfer surface ar ranged in two passes is served by two 13,000-gpm circ-water pumps driven by 100-hp motors; takes water from Ashley River Charleston's Electrical Demands Extension of new plant is planned as first unit goes into service. Station will provide major part of energy formerly purchased from the ** neighboring utility systems through interconnected lines 204,260 tb Turbina Generator, Before World War II. electric load in the Charleston area was supplied from a 19,000-kw steam plant in- the city and by transmission from South Carolina Power Co's hydro plant and neighboring utilities. The area's energy consumption grew from 89,000,000 kwhr in 1940 lo 216,000,000 kwhr in 1944. Peak demand grew correspondingly from 21.000 to 46,000 kw. An additional source of power was needed so a site for the new plant was acquired on the Ashley River, two miles north of the city. At this point there is access to deep-water navigation allowing fuel delivery by tanker or col lier: also, there is an adequate supply of condenser cooling water. Construction of Plant Hagood began Dec 1. 1945. and its first power was produced on Nov 20, 1947. The plant, named hu Beniamin A Hagood. first Low-press ' heater------ , g) STATION HEAT BALANCE uses three of four turbine bleed points. Steam generator has oir preheater, no economizer. Gas bypass in boiler controls steam temperature president of South Carolina Power Co. Plant Highlights. Planned to house was dedicated, on June 3, 1948. Plans four units ultimately, the station will are now being prepared for Unit No. 2. operate on the unit system with one Construction is to begin early in 1949 boiler feeding one turbine, and the gen and operation is scheduled for May erator connected to the system through 1950. one main transformer. First unit com The station, designed by the engi prises one 230,000-lb-per-hr oil-fired neering group of Commonwealth and boiler, feeding a 22,500-kw turbine at Southern Corp, southern division, very 850 psig and 900 F. Turbine exhausts closely duplicates several of its other at 2 in. Hg abs into a 20,350-sq-ft sur plants in the Southeast. One of them, face condenser. Heat-balance cycle is Plant Eaton, has been described in de simple, using only three of the turbine's tail in Power, Nov 1947, pp 90-4. four bleed points. The end points feed Accordingly, only a brief outline of the closed high- and low-pressure heaters highlights of Hagood will be given -and the middle point feeds the deaerat- here, principally where they differ from * ing heater and single effect evaporator Eaton of makeup water. No economizer is in- POWER ~ ~ ry I--3 RS-000174 1/17/02 NUECES 83 eluded in the steam generator although there is a tubular air healer. Two factors were thoroughly investi gated before starting construction: tl I subsurface exploration for foundation conditions 12 I effect ol rivet cm'.oni on cooling-water availability without causing recirculation. Subsurface Exploration. Test boring- showed sand anil clay existed to eleva tion minus 40. Below that was a level layer of marl, over 200 ft thick. The marl consisted of very loose, fine pai- ticles. 76'T- passing through a 200-mesh sieve. It has a void ratio of .TO, and specific gravity of 2.68. giving it a weight of 76.5 lb per cu (t. These data indicated the particles were in loo-e contact with one another and had not been subjected to much load. J'vmc settlement was expected ini! the question wa- iai-'d <.I whether :'ai- msrl would !low u" load :he -ann- a- elav that was a- line and loose atho marl. Test piling- were driven into ine marl and loaded with 12 time- the de-ign load to answer this question. No --'ttlerr.ent over a vveek s neriod wa- oli-':ved. and hence no trouble ot tiiinatiirc is anticipated. Effect of River Current. Ihedetma tecirculatm-. of condenser cooling water pn---:r led a new problem. So lar as we km - plants in this part of the eountrv n-- tidal water in the quan tities Hag 1 will utimatelv require. 25.00I'1 gp- per unit. Plant- inve-ti- gated - th*-1 on -(ream- that flow 1111! :- ! ' ne m or li.nl nun !i cooler 84 RS-000176 3 O W E R . . ov I9s? 1/17/02 NUECES PRINCIPAL POWER-PLANT EQUIPMENT Plant Hagood, Unit No. 1, north of Charleston,. S. C., South Carolina Power Co TURBINE-GENERA TOR: Turbine-generator ................................................................... General Electric Co Combustion-control oil pumps, 2.. .Worthington Pump & Machy Corp Rotary-gear, 38-gpm, 100-psi, 1150 rpm, 575-v, 5-hp motor drive 850-pxig, 900-F, throttle steam, 2-in. Hg abs exhaust, 4 bleed points, 2?,500-kw, 0.9-pf, 13,800-v, 3-phase, 60-cycle, 3600-rpm, 100-kw di rect-connected main exciter, 4-kw direct-connected pilot exciter, hydrogen cooled. Oil filter, 540 gph..........................................................................................Bowser, Inc PIPING, VALVES AND INSULATION: General piping contractor..............................................Grinnell Company, Inc Insulation contractor.................................. Phillip Carey Manufacturing Co G,,e and .obe va.ve,..........| V`" Condenser............................................................ CH Wheeler Manufacturing Co 20.350 sq ft surface, two passes, divided waterbox Circulating pumps, 2.............................. C H Wheeler Manufacturing Co Single-stage. 13,000-gpm, 430-rpm, 2300-v. 100-hp motor drive Condensate pumps. 2..................................... C H Wheeler Manufacturing Co 3-stage. 400-gpm, 1150-rpm, double-suction, 575-v, 75-hp motor Air ejectors, 2-stage...................................,C H Wheeler Manufacturing Co Priming ejectors................................................ C H Wheeler Manufacturing Co Small high-pressure globe valves... .Manning, Maxwell 8c Moore, Inc Check valves .................................. The Chapman Valve Manufacturing Co Stop-check valves .........................................................................Lunkenheimer Co f Atwood & Morrill Co, Crane Co, FisherMiscellaneous valves.. \ Governor Co, Hagan Corp, Merco-Nordstrom L Valve Co, Henry Vogt Machine Co Steam traps ................................................................Armstrong Machine Works STEAM-GENERATING EQUIPMENT: Boiler .................................................................................................... Riley Stoker Corp 975-psig design, 875-psig operating. 230.000 lb per hr, 11,700 sq ft convection surface, 7855 sq ft waterwall surface, 13,400 cu ft oilfired furnace Superheater............................................................................................ Riley Stoker Corp Convection, inter-bank, 9550 sq ft surface Air preheater........................................................................................Riley Stoker Corp Tubular, 31.500 sq ft surface Forced-draft fan ................................................................ American Blower Corp INSTRUMENTS: Draft Gages .................................................................. Republic Flow Meters Co Flowmeters .................................................................... Republic Flow Meters Co Indicating-pressure gages ....................... Manning. Maxwell & Moore Inc Recording-pressure gages .....................................Republic Flow Meters Co Indicating thermometers .............................................. Taylor Instrument Co's Recording thermocouples ............................................. Leeds & Northrup Co Conductivity recorders ....................................................Leeds & Northrup Co Water-level recorder ................................................ Republic Flow Meters Co Co- recorder ........................................................................... Leeds & Northrup Co 77.500 cfm at 1180 rpm, 57,500 cfm at 875 rpm, 2-motor drive-- Liquid-level indicators ........................................................................ Foxboro Co 200-hp 2300-v, and 7S-hp 2300-v Instrument boards ......................................... Clement Industrial Electric Co Induced-draf( fan ............................................................ American Blower Corp 140,000 cfm at 705 rpm, 99,000 cfm at 500 rpm, 2-motor drive-- 450-hp 2300-v, and !50-hp 2300-v Blowoff valves ............................................................................ Yarnall-Waring Co Water columns, 2..................................... {Diamond Power Specialty Corp l Reliance Gauge Column Co Safety valves .............................................. Manning, Maxwell & Moore. Inc Soot blowers ...................................................Diamond Power Specialty Corp FUEL-HANDLING AND BURNING EQUIPMENT: ELECTRICAL EQUIPMENT: Main transformer ................................................... Westinghouse Electric Corp 18.000-kva, self-cooled, 24,000-30,000 kva, forced-air cooled 13,800-v delta/44,000-v wye, 3-phase Station-service transformer ...............................Westinghouse Electric Corp 2000-kva, self-cooled. 2500-kva forced-air cooled, 13,800-v delta-2300-v wye, 575-v wye, 3 phase Standby station-service transformer............Westinghouse Electric Corp 2000-kva, self-cooled. 2500-kva forced-air cooled, 44,000-v wye, 2300-v Unloading pumps, 2, 250 gpm against 120 psig... . Quimby Pump Co wye, 575-v delta, 3-phase Booster pump, 50 gpm against 120 p$i. motor drive.Quimby Pump Co Oil circuit breakers, 46-kv................................ Westinghouse Electric Corp Booster pump .................................. Worthington Pump & Machinery Corp Disconnecting switches. 15-kv. .. Railway & Industrial Engineering Co SO gpm against 120 psig. duplex reciprocating steam drive Disconnecting switches, 46-kv............................Johnson Manufacturing Co Starting pump. 15 gpm against 300 psig, motor dr. ..Quimby Pump Co Burner pumps. 2. 50 gpm against 300 psig. motor drive Switchyard structures ......................................... Lehigh Structural Steel Co Power and control cables ....................................................................Okonite Co Quimby Pump Co Burners, 6. horizontal-flare type.......................................... Riley Stoker Corp Oil guns, 6. mechanical atomizing........................................The Engineer Co Combustion control, oil and air operated. . .Republic Flow Meters Co * Storage tanks. 2, 20.000 bbl each............Chicago Bridge & Iron Works Duct work .................................................................Birmingham Fabricating Co Station-service switchgear ...:....................................... General Electric Co 2300-v metalclad, 2500-v 600-amp breakers with 50,000-kva interrupt ing rating Station-service switchgear, 575-v............................ITE Circuit Breaker Co Station-service switchgear, 208-v...................Westinghouse Electric Corp Motors ...........................................................................................General Electric Co FEEDWATER EQUIPMENT: Generator neutral reactor.................................................... General Electric Co Boiler feed pumps, 2...................................................................... Ingersoll-Rand Co Main control switchboard ....................... Clement Industrial Electric Co 8-stage, single-suction, diffuser type. 550 gpm at 2490 ft total dynamic Lighting equipment ............................................Westinghouse Electric Corp head. 3550 rpm. 2300-v. 450-hp motor drive Storage battery.......................................................Electric Storage Battery Co Feedwater heater. 7th stage......................................... Foster-Wheeler Corp 880 sq ft. 2-pass, 1400-psig water, 350-psig steam Feedwater heater, 12th stage .................................................................. Elliott Co Vertical deaerating type. 225,000 lb per hr, 50.000-lb tank Feedwater heater. 16th stage...................................................................... Elliott Co Horizontal. 4-pass. 765 sq ft. 250-psig water, 50-psig steam Evaporator ....................................................................................Griscom-Russell Co 7500 lb per hr. single effect, bent tube, 350-psig steam. 100-osig vapor Evaporator feed heater.................................................................................Elliott Co Vertical deaerating type, 7500 lb per hr. 15 psig Feedwater regulator, oil operated..................... Republic Flow Meters Co Heater drain pump......................... Worthington Pump & Machinery Corp 2-stage, condensate-type, 40-gpm. 300-ft. 3480-rpm, 575-v. 15-hp motor MISCELLANEOUS EQUIPMENT: Water screens. 2, traveling............................................................. Chain Belt Co Turbine-room crane, 25-ton............................................................................WhitingCorp Boiler-room hoist ..............................................................Robbins & Myers, Inc Service tanks ....................................................... R D Cole Manufacturing Co House-service pumps. 2...................................................................... Ingersoll-RandCo Cooling-water pump ...................................................................Ingersoll-Rand Co Sump pumps, 2 .....................................................................Yeomans Brothers Co Chemical feed pump .................... Worthington Pump & Machinery Corp Service-air compressor ..................................... Chicago Pneumatic Tool Co Control-air compressor .......................................Chicago Pneumatic Tool Co Radial brick chimney.... Alphons Custodis Chimney Construction Co drive BUILDING CONSTRUCTION : Evaporator feed pumps. 2....................................................... Ingersoll-Rand Co Excavation, piling, substructure and superstructure 2-stage, end-suction, 20-gpm. 255-ft head. 3450-rpm. 575-v. 5-bp motor drive ** Standard Construction Co Building steel work ......................................................... Steel Construction Co Heater drainers and controllers........................................Fisher Governor Co Design engineers ......................................... Commonwealth & Southern Corp water during the critical load period. To determine water movement be tween tide? a number of sticks were placed in the river at lire plant site at high tide. Stick movements were charted with the changing tides. Samples of water were simultaneously taken from top and bottom at various tide stages and temperature density measured. As expected, the bottom water is cooler and denser. These data-- together with cal culated dispersion and the fact that condenser-discharge water is hotter than river-surface water during August and hence would remain on top--led us to conclude that three units could be supplied without recirculation. Some slight difficulties might occur with the 4th unit. This wa. taken care of in the design bv placing the intake at --30. the bottom of the river, and discharg ing cooling rvatei into a creek about 1200 ft from the intake. No difficulties are expected under adverse conditions. Detail design for No. 2 unit, dupli cating original installation and prelimi nary design for No. 3 has begun. The Gilbert Associates. Inc of Reading. Pa. have been retained to handle this engi neering. Construction on No. 2 is sched uled to begin early in 1949. The unit is* expected to he in operation in the early summer of 1930. POWER RS-000176 1/17/02 NUECES 85 Design Points You Need To Build a Blowoff Tank ><tfK^>^KKV'V,X>-i Actual steps in laying out an adequate-sized boiler blowoff tank can get lost in a maze of codes and regulations. To help understand the problem, ^tanley H Sye, mechanical engi neer, Ford, Bacon & Davis, designs working tank step by step i \ Boiler blowoff tanks are widely known power-plant equipment. Yet be cause of the many podes, some conflict ing, that govern tai^k installation, con struction, size, vent and discharge lines, the design elements arop out of sight. But before we talk'design let's review the function of a blowoff tank. It is primarily a safety device put in service to stop the practice of discharging a high-pressure boiler direct to atmos phere. In plants where blowoff lines -from such high-pressur^ boilers can be sealed by river, lake, or (jther large body of water, the blowoff tank may not be needed.' \ How does the blowoff. tank perform its service? It^ provides1 the necessary space for blowdown steam and water to lose pressure and temperature before discharge to atmosphere.ur sewer. A recent and valuable paper* is the basis for the graph in <.Fig\2. This graph, in turn, forms the! basis mr the following method of blowoff-tank sign. Tank Example. Let's ass ume a steam generator with a capacity if 460.000 lb per hr at 900 psig and 00 F at the superheater outlet. Pressure drop across the superheater at this steam ing rate amounts to 75 psi.i Steam pres sure in the drum is 975 psig, or 990 psia. | The blowoff tank's vent hipe is arbi trarily picked to give maximum pres sure drop of 10 psi between tank and atmosphere. This sets the blowoff-tank pressure during blowdown at 25 psia. From the steam tables we fiAd. 1 Entlialpv liquid al 990 psia--540.85 Enthalpy sat steam at 25 psia--1160.6 Enthalpy liquid at 25 psia--208.42 Flow of a Flathi*o \tir1ure. Benjimin .t: Miller. Trsu-: acftottr .45WE. Vol 64. No. 7. pp 557-6 69 \ With this information as a starter, j we can arrive at the pound# of steam.'' flashed 1o atmosphere per lb of blow Blowoff tank sketched to scale helps in determining the dimensions needed down. wie can figure amount of steam per blowdWn by equating the enthal py of liquid, at 990 psia to the product of enthalpy <>f saturated steam at 25 psia. and pouiids of steam flashed to at mosphere per l\ of blowdown, plus the. enthalpy of liquid at 25 psia, less amount of this liquid in steam flashed. Or stated in an 'algebraic equation: 540.85=1160.6 (.Y)V208.42 (1-Y1. A figures out 0.35 lb V>f steam per lb blowdown. \ So for every pound of W3ter blown down from the boiler. 0:35 lb flash to atmosphere, and 0.65 nn\st go to the holding volume of the blowoff tank. In normal operation this 0.65 lb displaces an equal amount of cool water to the sewer or other point of disposal. Blowdown Weight. Steam drum of our 460,000-lb-per-hr generator meas ures 60/in. dia by 36 ft long\ inside heads./Our blowdown, a customary A'A in. in the-gage glass, can be translated to,volume. This volume is 5 ft dia x 36 ft Tong x 4.5 in. -=- 12 in. per ft. or 68 cti ftipf a liquid at 990 psia with a specificyolume of 0.02155 eu ft per ib. Weight oiVater per blowdown becomes 68 cu ft -r- Ch02155 cu ft per lb. or 3108 outlet connection as indicated by dimen-ion A, Fig. 1. This volume should be at least twice the volume of the water entering it per blowdown. It is 68 cu ft minimum here--a 460,000-lb-per-hr boiler, 5-ft drum. T^nk Dimensions. We can now start on the. blowoff-tank dimensions. Let's pick one\6 ft in dia. Its cross-sectional area is 28>^7 sq ft. With this tank dimension, ^Nigures out 681-28.27. or about 2 ft, 6 in/\ Our next step is to size a vent pipe. From plant layout drawings we can es timate closely the equivalent length of blowoff pipe between boilei^and tank, allowing for valves, fittings aqd bends. For our tank example it comes, out as 300 ft of 2-in. schedule-80 pipe\ And the equivalent length of vent pip^ is 100 ft: The diameter of 2-in. schedule80 pipe is 1.94 in. With this background we can com pute the factor 0.144 L (ft! =- d (in.l, the abscissa of Fig. 2. or 0.144 X 300 h1.94, and get 22.27 factor for the blowoff pipe. lb. Of this. 0i65 \ 3108 goes to the holding volume \f the blowoff tanks-- total of 2020 11). \, Now let's translate\his 2020 lb to its volume in cu ft. Specific volume of liquid at 25 psia is 0.01692vcu ft per lh. So the volume is 2020 X 0.0V<j92. or 31 cu ft going to the holding volume of the Our chart. Fig. 2. published by Tube Turns, Inc, enables us to pick off the flow rate for a boiler pressure of 975 psig and a factor of 22.27. This shows on the chart as 49,000 lb per hr per sq in. of cross-sectional area. So total blow down flow rate for a 2-in. schedule-80 pipe of 2.95 in. in cross section is 49.000 blowoff tank. By holding volume we mean the vol ume contained between the bottom of the internal pipe and the bottom ot the X 2.95, and equals 145.000 II) per hr. Flow Rate. We established, above, that for every pound of water blown down from the boiler. 0.35 flashed to 86 POWER Jaouarv I5-3 RS-000177 1/17/02 NUECES