Document dQaG174wejKjq793O0LO1eyL0

More TECHNICAL BRIEFS. provided with a single element (water . level) feedwater regulator, 01 all the (actors enumerated, the most disturbing (rom the point of view of presenting calculations to determine the available NPSH under transient eonditlons is the behavior o! the feed water flow during thot period of time. Any assumption* of the results of a load drop upon the immediate behavior of the feedwater flow ore, therefore, somewhat hazardous. It would be de sirable, therefore, if not to eliminate the need (or these assumptions entirely, at least to postpone them. U, instead of determining the actual pressure de cay rate In feet, per minute for one given flow, we were to express this de cay rate in terms of the volume pumped for the entire range of pump flows, we would be in the position to compare this rate with the allowable decay rale aimilarly expressed and establish the max imum flow for any given load drop below which the allowable rate exceeds the actual end below which the instal lation is always safe. This process is, of course, simple fur the allowable decay rate. In effect, if we divide dP/dt [allowable rate of de cay in feet per minute) by dq/dt (pump flow, in gallons per minute) we obtain a value of dP/dq which represents the allowable pressure decay In feet per gallon pumped. The results of these calculations /or the installation de scribed are shown graphically. Hie authors then carry on in lhi manner to diacuaa other problems for open cycle end closed cycle feedwater operation as well. ASME Paper, No. 53F-32. TO OBTAIN COMPLETE TEXT Material for these abstracts comes from the following sources unless otherwise stated. Order complete paper from sources, not POWER. American Society of Mechani cal Engineers, fall meeting, Oct 5-7, Sheraton Hotel, Rochester, N, Y, Identified by initials ASME and obtainable through ASME, 29 IP 39th St, New York 18, N. Y. Association of Iron and Sleet Engineers, annual convention. Sept 28-30, IPilliam Penn Hotel, Pittsburgh, Pa. Identified by ini tials A/SE and available from T J Ess, secy, AtSE, Empire Bldg, Pittsburgh, Pa. YARD COAl STORAGE consists of inactive and octlve volumes Shaded portion of dloprom shows inactive volume of 16,000 tens Improved Controls Reduce Coal Handling Costs Coal MandOno Facilities with Automatic Remote Control Features. By H C Schweikart, Gilbert Assoc. Coal handling facilities ranging in cost from tS.OO to $20.00 per Installed kw and averaging about 7% ol the total power plant eost have not made their (air share o( progress in reduction in cost of equipment and operating labor, improved load factor and extension of automatic operation. During the past decade the capacities, pressures, temperatures and efficiencies ol individual turbine generators, steam genersters and asaociated auxiliaries have Increased considerably, resulting In lower savings of installation and maintenance costs per kw and requiring fewer operators. This progress has been aeeomplished by fundamental changes in design but aided to a considerable extent by more and better controls, pri marily automatic or at least remote manual. By contrast in genera), at the larger units required greater quantities ol coal, the capacities ol the bunkers, belt conveyors, crushers, feeders, etc have merely been correspondingly in creased 'with the . usual intermittent, manually supervised operation confined to approximately 10 hours eaeh week. This paper describes the coal han dling facilities being designed (or the Milliken Station and incorporating some automatic features that are expected to result in lower installation and operat ing costs. Bunker capaeity was given careful consideration. TVith a conventional coal conveying system involving trippers etc, bunkers of two different capacities were considered. The smaller bunker with a width ol 55 (t and 22 It depth had a capacity ol 1400 tons equivalent to 26 hours on s maximum burning rale basis. To obtain a bunker capacity of 2000 tons equivalent to 10 hours of maximum burning rate by increasing the height alone (20 ft) would Increaso the Cost by $63,200. II the increased bunker capacity were obtained by adding to both the height (10 ft) and width (19 . It), the cost would increase by $74,100.."sit Thus the incremental cost ol the bunker i^ is in the order of $131 per ton ol co] ' stored. These eoits include conveyors, `Jbl bunker steel, building and foundations! ; $ The final plans actually provide far , V a steel bunker having a capacity ol only 700 tona which is sufficient to operate the aleam generator for 14 hours at the maximum rating of 1,000,000 lb of team per hour when the fuel burning rate will be 50 tons per hour. The bunker capacity might have been even smaller without undue jeopardy to con tinuity ol eoal supply perhaps in the order of 400 tons or 8 hours at max imum steam generator rating. The ac tual capacity decided upon was bated on building volume resulting tram es tablishing the height by extending tbs roof above the bunker st the same ele vation aa the turbine room roof, estab lishing the length and width by the $|C*oal Is whet ou find it. Fortunately, however, a large share of the space required by the pulverising equip ment. ft is our considered judgment that the 700 ton bunker Incorporated in tbs continuous aulomalio reclaim schema provides more active storage than the 2000 ion bunker incorporated in s con ventional cool handling Installation. A ^'nation's operating Bituminous mines are located in Baltimore & Ohio ifterritory--economically accessible to America'sgreat industrial (/\ plants. fcThe Bituminous mined here--practically on ^Industry's doorstep--is of excellent quality and .tj|in wide variety; whatever your specific need, / gthere are B&O coals to meet it. Furthermore, 2000 tan bunker is somewhat on the conservative side since our own or ganisation now has 4000 ton bunkers under construction on similar sixe units .`the supply is inexhaustible--you can count on an unlimited reserve of B&O Bituminous, $.even in emergencies, for centuries to come. for a different client. All coal delivered to the station is firat conveyed to storage. This portion ijp . When you consider fuel, consider cost-- ^dependability of service--accessibility. of ihe facilities Is operated manually on an intermittent schedule. The yard- storage consists ol an inactive volums ol some 500,000 tons and an aotlve vol ume ol 5100 tons supported over four reclaim hoppers each incorporating 300- . tph remote controlled feeders. sch ,3 You'll choose the Bituminous mined on 3fcthe B&O. For advice, ask our manf BITUMINOUS COALS FOR EVERY PURPOSE pair of feeders deliver coal to 300-tpk crushers. The coal leaving each crusher can BALTIMOllF & OHIO RAILROAD be discharged to either one of two 300(Continued on page 226) Constantly doing things--better I READER SERVICE SECTION fOWH DECEMBER 1953