Document QkOz7m4Nw5YnoMooEvK2OE4pv

STORAGE LOSS IS SMAU Mot! (Mb noy b te**6 lr teitg period* wlllitvl uflsi Ion ol "guolily." T*u thuw ten ol booling yolwo do*'l utvolly onood 1% Ibo lk* y*or, ixopl for tew-Maiifc cool*. which Moy Iom up te 9% lit fieri poor. Woothoilng tend* to Mok* otl cool* 'clock," ibol It, tMin o re duction In tit* or crwiobllng. Slock ing l grooloit lor low-rank cool* end noer *rorag*-plta cvrfocoi. Tk*rt U alto iono pocclblllty of Ion of "coking" and Ignition qualltl**. Tboio effoolt ore ViiMlIy negligible. So, when ll <enti lo outdoor tor. ogt, o*on lor long porlodt, your prloiory conceit li lo guerd ogalnit booling end "flroc," (coo bolow(. YOU START TO BUILD AN OUTDOOR STORAGE PILE: will dm*"*** orao lor tool itorag*, lr of Mondlng wo*r. li ii ral:*d, not ivbjatt lo flooding from noerby Urtomi or kg/l fra" odjoctol ground jm*-,mH o'to im'l ovO(tebte, intioll drolnogo ditch*:, run^l*ng'b of I11* `lots 'I1* '! kurtaln ground It tolid, not loot* end porout and nol clndnr V|f' peuibl*, grodo to uniform 1**l. Som*lim*t ttorog* or*oi Rlpp.drnnod or hard-ivrfoctd with paving moterlali pile |A *utc*lv* loyri, nol morn Ibon t-ll thick and Wt**r*v*r poitibln, compocl ooch lay*r g^yll* by tlopteg top* ol ucc*nlo teyrt and lop ol compl*t*d ^"loword tid*i, lo prvnl rein or mailing rnov and it* at{*Noting and pnnatrating into lh* pllo Wf pfl*di lnmp*olro chock: of th* pit*, porliculorly ol odg j^Mld* itepni. I*m*b*r, I00P it critical l*mp*rolur* y pH, *i far ot poitibl*. A 6-In. loynr ol tinoi, anchorod again*) -mtlnn bv o carolully placed <0r: loynr, i: good DON'T N*v*r loo** r*fwt, wood, ttrow, growing *g*tolion or any olb*r orgonlc molciiol itonding in On oro yo* tolocl lor cool torag* Don't pH* cool oround if*l 0 woodnn po:l, cron* :uppart:, *tc. Pil* dtniily U bound to b* lowor oround lh** marl: fhon in lh* pll* proper, providing #nh for olr ond go: mov*n>*nt Novo* attempt to vonlllot* o pllo with pip*: or wood*n duct: for th* iom* r*otoni you ovoid piling cool oround upright: lebov*l Don't itor* tool n*or tteom p<pl, imok* itocki, bolter blowofl lino:, h*ot*d *l*m*Ah of ony kind Don't lull dump cool on pll*. Droppnd cool :*gr*gol*. forming nolyrol flu*: for ok movomunl through pit* Compocl unn'tod cool only. Siivd cool :lo>* woll hul not by compoctlng method. II you *toro :li*d ond un:ltod, k*p :*porol* Wk*i y*u can't compact, ond cool itn'l :U*d, avoid conical pite: by dumping in imoll <onlinuou:ly evorteppSng pilu: Don't mok* pite lid*: too il**p. K*p b*lbvr 45 dog, with 90 dog a good dope to aim at. Steeply doping tide* ri:k *g**gellon safe storage depends on proper piling methods Today, more plants than ever And It smart to stockpile coal outdoors. It's always been necessary lor some -- plants along waterways subject to freexupt, lor example. But supply and transportation dislocations during war years and strikes have led many others to follow the practice. Even aside from the emergency reserve angle, there's often sound economic sense in being able to buy coal during *`o(T' seasons. Safa Storogo, Whether your storage is large or small, you want protection against lots by weathering and by spontaneous combustion. And If meth. ods now well-known are used, outdoor storage, even in large amounts and for long periods, can be practical and safe. All coals tend to combine with the oxygen of the air. Frequently this is an extremely slow process, often called weathering. There's some loss of heat ing value and change in firing charac teristics. But if conditions are right, the action can move foster and we have heating or spontaneous combustion. Knowing what eauses this is the key to avoiding storage-pile fires. Coal-Pllo Hooting. When eoal com bines with oxygen, heat is given off. If heat isn't carried away, temperature rises. As it does, the reaction with oxy gen, like all chemical reactions, speeds up. So we have a vicious circle -- heat, temperature rise, faster reaction, more heat, higher temperature, still faster reaction, etc, until the coal actually bums in the normal sense. There are two basic ways of com bating this action. We can make sure that air moves through the pile fast enough, and uniformly enough, to car ry away heat without appreciable tem perature rise. Or we con try to cut air flow through the pile to a minimum to reduce possibilities of reaction. Storing Slxed Cool. What might be called the free-air-flow method is the simplest but is limited In application. Only with sixed coal, which leaves more or less uniform air passages in the pile, can we depend on this scheme. In smaller plants, particularly the few remaining hand-fired ones, this works welt. But larger plants rarely buy double-screened coals, and it fines ere present it's necessary to use methods that cut air flow to a minimum. Let's see why this is so. Avoiding Segregation. If Anes are present at well as coarse lumps, we run Into the problem of segregation. This offects other parts of the handling end firing system but right now we're con cerned with its effects on storage. If, in the ordinary way, we dump coal on a pile, the fines tend to stoy in the center and the coorse lumps roll to the out side. Such segregation in a coal pile gives areas or lanes where air flows readily and others where it hardly flows at oil. Somewhere in such a pile, we're sure to get just the right combi nation of air flow and heating to pro duce spontaneous combustion. So the first step is to avoid segregation. Best defense against segregation is- 4 layer piling. To build a layered pile; . spread the coal thin over the storage area. Where coal Is dumped from . buckets, redistribution may be neces-. ory. With equipment like drag scrap- ' era, bulldoxera, 'rubber-tired scrapers, ` layer piling it merely a matter of prop er procedure. Even trueks con be used to build a layered pile (Power, Nov 1942, p 66). Regardless of equipment the important thing is to build the pile in tuccessivc layers and to keep them thin -- less than 2 ft, with 6 to 13 in. being best practice. Compacting, Such piling tends to mix coal, eliminate segregation. Bui for troublefree storage, we'd like to pack the coal tightly to cut air Row through the pile to a minimum. Loose coal, /or example, has a density about SO lb per cu ft. In ordinary stor age piles, density builds up to some 58 lb per cu ft at the bottom of a 20-ftdeep pile. By compacting, we can raise density to 65 or 70 lb per cu ft Compacting goes naturally with Uy- er piling. Each layer can be tamped or rolled to pack it down. Usually, weight ot equipment used to spread coal proves adequate. Bulldoxera and scrap ers, (or example, do an excellent job of compacting. - A word about coal siring is worth while here. Don't compact slied eoal* without fines. Double-acreened coal* should be stockpiled separately, by tbs free-alr-fiow method. Where coal b If you locate a hot spot, or have a fire: ^|lj;`iv ever or hold* hoofed tool (2| recompod pil*. Marling ol '.-tain end working inword (9) if pil* i: trnoll ond or*o permit:, u'in tool ond ra:pr*od ll (4) fry lauding CO: into pil*, uilng lilted will: wall-drilling point* or with hoi*: in tloll*n*d and In culling owoy hoofed cool. don't dlMurb lemolnlng cool. Don't apply woltr lo h*ald ot*o. TH* lire moy appor to b* quenched alter looking, but you i*t up condition: lik*iy to produc* o rcurr*nc* ol lh* hauling within o very low day: -ikeived run-of-mlne, crushing before .-jrtorege is the usual practice. /.'Properly piled and compacted, coat ;.ftandi with hard vertical walls when ./.'aesvsted. The pile itself is firm and -kird and water runs off slopes. Yet the dopes are the weakest tone. Segrega`.lion is apt to be present in side slopes tnd wind can force air into sides. A' Jooling lho Pile. Slopes can be safeVfiiirded in several ways. Where mobile -Wipment is used for piling, bull- dosen should be run up and down side 'djpes as the pile is formed. This com pacts slopes but means a relatively ;*ullbw angle, which la a disadvantage If.area is limited. You can, of course, turound pile with embankments or coal in a basin with protected teles. But this raises problems in re-, . filming gtored coal. '.Sealing the exterior surfaces of the is probably the best all-round on* '.*cr. Asphalt and other coating mate! arc used, but general practice to4*7 is to seal with a layer of fine coal, ; A b. or so thick. A carefully placed ''hyer of coorse coal anchors the fines *t*inst wind erosion. If Pile Overheats. A properly built and sealed pile should give no trouble, but you shouldn't just forget it Probe the pile regularly to check temperature. If it gets up toward 160 P anywhere, you've got a bad spot. Don't try to put out the fire with water. It can stop heating only if it reaches just the right pot and is apt to cause problems of its own. Extra compacting in the heat ing area may cut air flow enough to throttle the reaction. But best plan in most cases is to remove affected coal without disturbing the remainder. Spreading the heated coal will usually put out the fire. Normally, it's better to use coal you salvage from on overheated area rather thon try to repile it. Some users have been successful in putting out coal-pile Tires with COj. A pipe fitted with a well-drilling point is driven into the pile and COa allowed to bleed into the offected area. If drill er's points aren't available, end of pipe can be crushed and holes drilled in it. Similar methods have been used in fighting bunker fires and some bunkera have been fitted with piping ond de flector plates for COj. Cool Selection. Pour substances seem to contribute most to the reac tions involved in weathering, heating and spontaneous combustion -- iron pyrites, water, oxygen and certain of the hydrocarbons. Theory - says iron pyrites, water ond oxygen combine to form iron sulfate and sulfuric acid in an endothermic reaction. This triggers carbon and hydrocarbon reactions with oxygen. Normally all that happens Is weathering but, as we've seen, if air In the right amount feeds this reaction, and heat speeds it, we have trouble. Today's cleaning and wothing equip ment at the mines removes a portion of The iron pyrites (what .often con stitutes the coal's sulfur content) and some seams run low in sulfur anywoy. Prom the storage angle,-this points to electing a coal comparatively low In iron sulfides or iron pyrites. Yet it usually isn't practical to select coal from the storage viewpoint, and more often the problem Is to store the coal we have or normally receive. So, in the lost analysis, proper storage methods are the answer when you must stock-/ pile coal for long periods outdoors. FUE! MANDIINO AND JTORAOf fOWf* \j *CtMREI 1953 tun HANDLING AND STORAGE 5