Document bBb1rj4krDQq1yDmYaNEKnzj6

TABLE I--CONDENSERS OF THE TALLEYRAND GENERATING STATION l/nil Dole /Vo. started Make Surface area, *9/1 3-21 6-18 9-24 1-29 3-39 Wheeler Wheeler Wbodcr Wheeler Weatlnghouoo 22,500 11,000 22.500 39.500 46,000 Area, --Pump capacity--* Number *9 Ji 9pm per ho 1 pump 2 pumpt X Tube Isi^rlb, 2.25 2.7S 1.80 1. SB 1.23 12,200 12,200 15.000 28.000 33,000 23,550 44.000 51.000 4156 238S 41S6 6874 7950 At) Lobes are No. diameter, No. It RWQ 20# 18# 20# 22# 22# ------- Water velocity i - 1 pump--. . /nlei (Juliet pan pate 2.67 4.67 3.20 3.99 4.29 3.20 5.56 3.94 4.20 4.32 isms and industrial waste deposits are our problem. Microscopic examination of river water and slime shows the mix ture containing fungi, an abundance of Crenoihrix forma, dead molluaks, bac teria, bacterial toogloea, filamentous algae, diatoms and Protozoa. A culture examination reveals large liquid bac teria colonies composed of small eoeoid capsulated, gas-producing forms. Chocking Operation. Changing con ditions led to early efforts to evaluate over-oil heat tronsfer coefficients that we could apply to practical operation. In 1931 the first bogeys were estab lished for expected operating vacuums for given loads, circulating-water quan tities and temperatures, from the con denser contract guarantees. These then gave a basis for evolualing' loss from condenser fouling, Fig. J. In 1936 we developed the cleanliness factor derived from the over-all beattransfer coefficient. In making the formula an adequate working too), effect of water-velocity changes through the lubes and of temperature were studied. Actual experimental data taken in 1937 on each condenser estab lished the necessary correction factors. Conslroction of unit No. 7 took most of 193B and 39. In July 1940 the relatioa between heat transfer and water velocity wes established. Cleanliness factor became a performance guide and practieal working tool. By June 1941 all computations were standardized. The 100$ cleanliness factor corresponds now to a corrected heat-transfer coeffi cient of 360 Btu per q ft per hr per deg F. Much work can be eliminated in adopting this method if clean new tubes can be used to establish the bogey value of the coefficient Cleaning Methods. Cleanliness was no) a serious problem immediately fol lowing insiallaiicn of No. 6 unit Pollu tion was relatively small and electric load was one-fourth whot it is today. When condensers did foul with slime, mots and mussels it was no particular trouble or expense to shut down the unit for cleaning. Steam costs ware about 15c per 1000 lb with fuel oil at 68o per bbf. Loss in vacuum was about 13.50 per day for each l/10ib inch excess backpressure on .No. 6. Rubber plugs, blown through with compressed air, scraped off sJune from tube lateriort. Condenser cleaning cost about $60 per unit; a rough method prorating condenser cost over the num ber of service doys was used to judge when to clean. Throughout 19324 the increasingly ineffective cleaning by rubber plugs was carried on. Men worked hours in a disease-laden atmosphere shooting the Condenser cleanliness factor offer cleaning Rubber plugging plw.w<iitHiirW)T.!i|'<auireihiw|tu:.viiiD.;ii|tH.:,ni'iHiitlljiirflV^v,l 66% Ait drying pvdmutneL.ninmiwn*uh,i^*L-.tmwiAnmu,rji-7aai;n$2% Acid treatment Chlorine treatment pimw-w-AaNHmMm mumtTV'imtii tugjJ^nwiiddj.i;4 -.CmijwViihPrSifl 100% 3Chlorinot(on of condensers clean* tubes entirely odor completion of eoch treat ment. Regardless of cleaning method fouling Increases progressively with use plugs through lubes. Fig. 3 shows (hii -$| method left appreciable amounts o) fouling in tubes. Dissatisfaction Irfi to searching for more effective method^ Observation of condensers, opend1 to atmosphere two to three v*lg 3 showed mud and alime curling tad '^1 R*- cracking off the surface as they dried-'?/ When placed back in service tbc *& washed out the dried 'scale tad du vacuum was improved. To speed nature's cleaning method,I experimentation with air drying viii'/J started on-No. 1 in July 1934, Txo.^ electric beaters of 3 Vw eeeb wen v placed at the discharge of a small 508 /[ cfm ventilating blower. It took .'Wj^l hr to complete the job. Air leaving lii >1 condenser barely reached 100 F. Wtt-. and dry bulb reading of inlet and out;*'1 let air showed 2520 lb moisture bsd.^ been removed. )., As in all development work, vsluabk''? end useful information wes'gslned irob A otherwise dnsuccessiuI experiments. provement In equipment and roclhsd ^ was rapid. Air drying wes stsodsrdittd*^ in 1935 with three simple rules (I) '-* fast method of beating most be *jV. able (2) free woter'left in the because of poor drainage roust beblovo,* out with compressed ajr (3) air soppjr ? . must be adequate. V. ' Live steam was Injected i"1 steam side of the condenser with _ limiting temperature of 145 F lrtW t!-Vi exhaust casing. Tubes in No. 5 ?.' [I have to be blown out, while No. 7 drsw `. ,J well. Four 1500-cfm fans weM ,U^*j ' Total time out for the unit was reduce to 12 hr; Fig. 2 shows typical aW*J'-;.\ ing data for a drying-out period. Air drying was superior to ber-plug method because B ..\V> more deposit, was equally f**t less sickness and reduced the labor involved. It still hod the ^ vantage of reducing machine ability; but the chief handle*? '''J* ;% same as all mechanical rnetbeds.^fif 80 (666) POWER No**mb,f 1 an experimental pilot plant in opera TABU II--ST. JOHNS RIVER WATER ANALYSIS VARIATION FOR THREE DIFFERENT YEARS November ------ July 24, i960----- December Water eonetUueni 1929 Sample t Sample 2 ms Total solids........................................ Suspttided solids............... . Total hardness as CoCOj................. Cufr-ium as CaCOi........ ................... Magnesium as CaCO*...................... pboiolpblhaleln alkalinity e CaCOi... Methyl orange alkalinity ae CaCOi....... Ftee carbon dioxide as CaCOi........ Ciiorfdes asNaCJ................... ......... Sulphates as NeiSO*......................... SOira as SiOt..................................... Ahimioa as MOi.............................. Iron a Fe........................................ phosphate as F*0,.......................... Hydrogen ten (pH).......................... 1079.4 284.0 m.o 178.0 0.0 59.0 7.0 942.0 181.0 14.0 }fW>i-9.4j 6.6 5590.0 1028.0 247.0 781.0 64.0 144.0 3866.0 761.0 0.2 7.1 7367.0 1302.0 282.0 1020.0 12.0 71.0 5)13.0 942.0 6.0 0.2 7.3 2672.7 10.5 444.6 164.2 280.4 0.0 53.0 0.0 2)54.6 287.3 8.6 1.0 0.0 7.3 Chlorine demand taken in 1933 * 3 ppm. Chlorine demand token in 1947 * 11 ppm tion June 1941. Results exceeded ex pectations; a net saving of 82026 was made the first operating year compared to the previous year. These savings were based on a chlorine cost of 9# par lb. Fig. I shows the improvement for the trial period, June 1941 to June 1943. Experimentation- proving successful purchase of a commercial installation was approved, but war shortages de layed it till after the war. During 1944-5 all plant equipment was on the line most of the time. The pilot-plant ehlorlnator, capable of handling only 4 lb per min of chlorine, failed to keep up with the job of supplying chlorine demands of 10 to IS ppm, especially in the faee of increased circulating-water utilization. War took its toll of skilled operator*, imposing greater burdens on those left. The pilot plant was a war casualty. TABLE III--ECONOMICS OF CONDENSER CHLORINATION TALLEYRAND GENENATINE STATION Cleanliness factor fell to an average of 38% the first six months o! 1946, Fig. 1. Steadily increasing oil oosts helped raise tbe condenser excess operating No. 7 condenser easts Excess steam coot due to fouling.................. Chlorine cost................................................... No chlorine used for year ending July 8,1946 $16,157.76 0 Condenser loes due to fouling....................... 916,157.76 Summary ttningr. No. T condenser, ete&ra saving..................................................... No. 6 condenser, steam saving (estimated at 50% No. 7}........ Cleaning labor.............................................................................. Sickness and accident................................................................... Better operating conditions....... ................................................. High machine availability............................................................ Intermittent chlorination, year ending July 8,1947 92,517.74 2,197.64 94,715.38 911,442.38 5,721.16 no czedii oo credit no credit no credit cost to 11450 a month. Installation of two Wallace and Tier- nan 6000-lb-per.day chlorinatore was completed June 1946, and believed to be ibe. largest setup of ita kind in Florida. Housed in a separate building .outside the plant, a 6-ln. rubber-lined . header carries the chlorine solution into the plant. Four- and 5-In. branch headers, with water-operated shutoff valves controlled electrically from the chlorine bouse, carry the solution to the point of application. Condenser* No. 5,6 and 7 can be treated simultaneously Total saving............................................ ............................................... 917,163.54 or separately. Every effort was made to install a flexible system of sufficient capacity to Insure adequate chlorina tion, whatever future demands might be. Two treatments ste being made eoch day to each unit in service. corrected the effect of alime Jonnolion but did not eliminate ita cause. Increased Fouling. During 1939 n paper mill was placed in operation adjacent to the station. The air-drying method was becoming less effective. Tube Interiors of No. 7 condenser had a costing of greyioh.green deposit, some* *hst flaky in appearance. Analysis indi cated tube corrosion with formation of wsier-ina0]yh!c carbonates of copper and tine; 73.8% of the material was b*tic copper eorbonote. Removing the we discovered a forge part of lube surface was pitted, althoagh the pits were not deep. Paper-mill waste 'wet discharged to the river Is highly Iksline, sample 2 in Table U. A different cleaning method was trcd. circulating a 3% hydrochloric acid solution through the water, side of the condenser. Preliminary experi ments showed no appreciable metal loss from copper alloy tubes or cast-iron water boxes in contact with this strength acid solution lor periods of 1 hr. Results were excellent, as In Fig. 3. This cleaning method requires block ing off the condenser dfscharge open ing. It also proved expensive, needing 34 earboys of acid at |5 each, which made ft undesirable for normal practice. Since hydrochloric acid proved so effective In removing copper carbonate, chlorination was considered. Chlorine in water forms hypochlorut acid, which kills slime-producing organisms and also reacts with the inorganic material. Realizing that chlorine applications differ with plant characteristics, we put Recently, failure of several sections of rubber-lined header because of poor fabrication led us to air-dry No. 5 unit. A return to this method hospitalized two of eight workmen, and two. other* *u(* fared disturbing illness. Stream pollu tion is continually increasing. It is not often thet equipment pur chased satisfies every consideration the way the chlorinating equipment does at Talleyrand. As an Investment the installation will pay for itself In two year*. Table IU shows the saving. From an operation standpoint, chlorine supply is ample when and where needed. Because of the local corrosive water supply, maintenance was the least satisfactory factor, requiring 300 manhour* the first year. (Continued on page 138) 'OWE, November )94B . (687) 81 i r.f