Adoptimn of nelv ccnceptsin material hand*ing irc cementand ather rnir.neral industries

Jai P. Gupta, Chief General Manager, P. K. Mittal, Chief General Manager,HOLTEC Consulting Private Limited, Gurgaon, Haryana

lntroductionlndian cemenf industry has

witnessed rapid growth in past2-3 decades. The overallproduction capacity of theindustry, which used ro beapproximately 60 milliontonnes in early 90s, has morethan quadrupled in about 20years.

Such rapid growth hasposed several challenges infront of the Industry, some ofwhich are:

. New projects ore forced to gofor difficult to occess / opproochlimestone deposits.

r Induslry being forced to goowoy from the morkets due todifficulties in lond ovoilobility /ocquisition.

o Unit sizes becoming lorger tohorness economies of scqle. Theusuol copocity of newproduction lines ronges from5,000 - 10,000 fPD clinkerproduction, os compored to2000 to 3000 TPD in eorly 90s.This is leoding to need for highe,volumes to be hondled.

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r Similor requirements ore olsoemerging from cool industry, nonferrous metol industries etc.

. The need for high copocitymoteriol movement qt o fosterrote ond inodequocy of roodnetworks in remote oreos.leoding to increoses relionce onroil tronsportotion.

The poper covers moiority of thesuggestions reloting to the mqteriolmovement through roil routes. Themoiority of moteriol tronsportotionincludes bulk tronsportotion of Cool,clinker, flyosh ond cement. Thispoper covers certoin conceptswhich could substontiolly reducelooding ond unlooding time. Theseconcepts hove been successfullyemployed by Holtec in cement oswell os other industries. ond couldhelp the cement industry inoptimizing expenses on moteriolhondling.

The paper covers the following3 concepts:

i. In motion looding of clinker orcool in roilwoy rokes.

ii. Use of bottom dischorge wogonsfor cool ond clinker tronsportqnd its eosy ond fost unlooding.

iii. Use of wogon shifters to reducethe oreo for the industriol units

required to hove rcilwoy siding.

The poper briefly covers theconcept, principle of operoiion ondhow it could be odopted by theIndustry. Likely benefits ond certoinpre-requisites, which ore neededfor odoptotion ore olso covered too certoin extent. ln cose of onycustomized needs, Holtec could beconsulted for further help.

In motion loading of clinker/coal in Railway rakes

For the moteriol tronsportconnectivity ihrough roilwoys,clinker/ cool looding is usuollydone through overlond hoppers,constructed on top of the roilwoytrocks ond looding of moteriol is

done through telescopic chutes.Depending upon the copocity ondspeed requirements, more ond morenumber of hoppers / silos cqn beconstructed so thot more number ofwogons could be loqdedsimultoneously. As per the usuolconcept opproximotely one rokemoteriol is stored in the overlondhoppers. The usuol time token forone complete roke, vories from 3-6hrs depending upon the number ofhoppers ovoiloble for looding ofmoteriql. Although more number of

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hoppers reduces totol time for fillingthe roke, but adds to othercomplications, such as:

. High number of equipments,their drives.

r Heovy to very heovy civilconstruction.

r Constroint of more permonenrstructures, os per roilwoy norms.

o Occupotion of lorge oreo.

r More number of operotors.

This poper suggests looding ofroil rokes in motion (Ropid loodingsystem). With Ropid looding syslem,the entire roke could be looded inobout 60-80 minutes, from o singledischorge point.

What is Rapid Loading?ln ropid looding of moteriol,

moteriol is looded on roke, whilethe roilwoy roke is in motion. Onesilo {of obout one full roke copocity}is constructed on iop of roil trock.Below the hopper, onother smollhopper is provided on lood cells,which con occommodote obout Iwogon lood of moieriol. The obove2 hoppers ore connected throughhydroulic gotes, ond lorge chute,so thot within seconds, moteriolgets tronsferred from the moinhopper to the pre-weigh hopper

{mounted on lood cell}.

Before o roke orrives, silo isfilled, so thot fost moteriol loodingon the roke, does not get disturbed.In the beginning the lood cellhopper is filled with pre-weighedmoteriol. As soon os the wogoncomes in position, the looding stortsond the complete wogon is looded,by the time it crosses. During theperiod of wogon chonge, pre-weigh hopper ogoin receives themoteriol from moin hopper, so thotby the time onother wogon comesinto position, it is reody with themoteriol. During this entire

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operotion roilwoy roke moves ot the

speed of obout 0.6 to Q.7 kn / hr.Thot meons o full roke of clinker

{obout 650 m in length} is likely toget looded in obout I hr of time.

A typicol pictoriol view is shown

Figure tr: ffapld lcadrng System ln0peratian

in shown in Figure 1.

The moiority of the collieries inIndio hove been using ropidlooding system for cool rokelooding. Adopting the similorconcept, Holtec designed one ropidlooding system for lignite. As thesystem wos designed for lignite, itwos substontiolly different from the

usuol ropid looding system,however hove been performingvery successfully for lost Z-8 yeors.At this locotion roke of obout 40wogons ore being looded in obout45 minutes. Although the system is

locoted close to o denselypopuloted oreo, but os it hordlygenerotes ony nuisonce dust,Owners do not foce ony difficultiesin operotion.

The moteriol filling ond closingore through hydroulic gotes, ondwogon positioning is sensedthrough the proximity switches. Alittle bit of mointenonce qnd corein operotion, hos been enough tokeep the system spilloge free.

The orrongement os instolled forlignite looding hos been depictedshown in Figure 2.

Expected Benefitso The conventionol system of roil

looding, requires 3 to 6 hrs forlooding of one compleie roil roke,whereos with ropid loodingsystem, the entire loodingooerqtion for one roke could becompleted in obout one hour.Assuming obout 3 hrs soving onone roke, could result into obout?000 hrs of rcke hondling time,for o clinkrizotion unit of obout 2mio tpo copocity. Such foster

Figure 2: Lignite !-aading System in Operation

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movemenis of roke, sholl help inbetter utilizoiion of rokes,especiolly if the compony ownsthe rokes.

The totol investment required forropid looding ore substontiollylower os comoored to theconventionol systems.

Numbers of drives required orevery few, os compored to themultiple units ond equipmentsrequired for conventionol systems.

Number of operotors ondottendonts required would be 2 -

3 (ot the time of looding) for entireoperotions os compored lo 4 - 5{ot the time of looding) forconventionol system due to thesize of the system ond highnumber of equipments.

o Dust nuisonce substontiollyreduces os compored to theconventionol systems.

Pre-requisitesFor the houling of roilwoy roke

ot o constont speed of 0.6 to 0.7km/hr, creep drive need to beinstolled on the locomotive. As thenormol locomotives from roilwoysdo not hove this focility, Plont willhove to mointoin their ownlocomotive for houloge of theroilwoy roke.

Use of bottom dischargewagons for coaland clinkertransport and its easyunloading

Troditionolly, cement industryhqs been using normol BOX /BOXN type of wogons for thetronsportotion of cool & clinker. Forthe unlooding of these wogons,wogon tipplers ore instolled,through which these wogons oreunlooded. As Roilwoys ollows 5hrs lime for mechonized unlooding,wogon tipplers were typicollydesigned to unlood full roke of 5gwogons in opproximotely 3-4 hrs

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time (ie 15- l8 wogons unloodingper hour).

As Roilwoys wish to go forlonger rokes, with lorger copocitywogons/ {recently RDSO hosreleqsed certoin new guide lines),occording to whic[, oll new

orrongement. As ogoinst normoltrock hoppers, Holtec designed overy simple but effective sysiem forlignite unlooding in the yeor of2A02, which is running successfullysince then. A brief description ofBOBRN iype wogon is os below:

instollotions {olter December 201 0)sholl toke into considerotion lorgerwogon size ond unlooding speedsholl be increosed to obout 25wogons per hour. As per the newdesigns of wogon tipplers, size ofwogon tippler ond its civilconstruction requirements hovesubstontiolly increosed olong withcopocities of the moteriol hondlingequipments down the line.

As such instqllotion of wogontippler ond ossocioted ouxiliorieswos expensive, ond recentenforcement from roilwoys, hosfurther escoloted the cost ofinstollotions of the wogon tipplerond its ossocioted ouxiliories.

As ogoinst BQXC ond BOXNtype of wogon, ollocoted in cementindusiry, power plonts qreollocoted bottom dischorge wogons{BOBRNI, which con be emptiedthrough pneumotic gotes instolledbelow the wogons. For thedischorge of such wogons, Thermolpower plont instolls long trockhoppers with plough feeders. Thisis ogoin quite expensive

Bosed on success of eorlierdesigns system for Ligniie, Holtec isdesigning onother system for othermoteriols such os cool, copperconcenirotes ond rock phosphote.AII these moteriols ore quite difficultto flow ond cquses substontiqlomount of dust nuisonce,occordingly the trock hoppers orebeing designed.

The proposed wogon unloodingsystem is quite simple, withunderground hoppers ond opronfeeder instolled for eoch wogonunlooding trock hopper. Typicollyqbout 7 to 8 minutes of time isrequired to unlood one set ofwogons, which include, wogonplocement, connection ofcompressed oir qnd unlooding. lfthe system is designed with 4hoppers, opproximotely 2 hrs oresufficient fo empty out completeroke of 58 wogons. With morenumber of unlooding hoppers, stillbetter speed of emptying could beochieved. The system requiresshore compressed oir orrongement,which needs to be connected to thewogons ond with one stroke the

BOBRN:Open hopper car with rapid{pneumalic) trotlom discharge dcors. air-braked. EOBRN and BOBR (see above)are most olten used for carrying coal tothermal power plants. and also for ore,stone, track ballast, etc" fach wagonholds some 60t of coal loaded trom ihe topand unloaded from the bottom by meansof the pneumatically operated doors. Thecontents of the ,wagon can be disehargedcompletely in about 15 seconds.

The door-opening mechanism is iriggeredby lineside devices running on a 24V or 32v DC source. As the wagons in a rake pass by thetriggering devices, their doors open and theif contents are unloaded into the pits below thetracks {the 'meny-Eo-round' system). The versions used by the power planls have 12 bottorndoors. whereas lR uses variants that have B doors.

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complete wogon gets emptied in omotter of seconds.

A generol orrongement of trockhopper hos been shown in Figure3A ond Figure 3B.

{Secfronal l/r'ewj

lf the lndustry insists for bottomdischorge wogons from Roilwoys,similor syslems could be used in theindustry, for cool ond clinkerunlooding. The system proposed is

quite simple, effective, fost ondeconomicql {not only on instollotioncost, but olso on its operotion).

Expected benefitso The conventionol system of un-

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looding {Wogon tippler) requiresobout 4 hrs for un-looding of oneroke, whereos with proposedorrongement, the entire un-looding operotion for one roke,could be completed in obout 2

wogonsr but groduolly fhey needto switch over. As mony of theindustry ployers ore interested to gofor iheir own wogons. it could bebetter to go for bottom dischorgewogons rqfher thon going for

Figure Tra* tlapper Unloading $ysfem (Elevation View)

hrs. This 2 hrs soving onone roke, could result intosubstontiolly lorge onnuolsovings, considering bothclinker qnd coolmovement by bottomdischorge wogons.

o The totol investmenrrequired for proposedsystem sholl be sub-sto n tio lly lowe r o s

compored to the wogontippler especiolly of newdes ig n (G-3 3, Rev-0 I

Moy 2010).

e Reliobility of the systemsholl be much better os

compored to the wogon iippler.

r Dust nuisonce substontiollyreduces os compored to theconventionol systems.

Pre-requisitesInitiolly could be difficult for the

industry io switch over to bottomdischorge wogons, os roilwoyshove limited quontity of such

conventionol BOXC / BOXNwogons.

Use of Wagon TraverserAs exploined eorlier,

nowodoys the trend is to go forIorge copocity clinkrizoiion units,locoted close to the limestonedeposit ond construct split locotedgrinding units neorer to the sourceof flyosh {Thermol Power Plonts).As moiority of the thermol powerplont ore locoted closer to thedensely populoted oreos, splitlocoied grinding units olso getslocoted in these oreos. Due to highdensity of populotion in theseoreos, lond is generolly expensiveond ocquisition of odequote sizeof plot for such units is olwoys ochollenoe.

As mosl of these grinding unitsore receiving clinker throughroilwoy rokes they need to instollwogon tipplers. For the effectiveutilizotion of wogon tipplers ond tomeet the time ollocoted by roilwoysfor unlooding, it becomes must to

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Figure 38: Track Hopper Untoading System

VOL.XXXII NO.2

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hove sufficient spoce (equivolent to

one roke lengthf before and ofterthe wogon tippler. There{ore eventhough the totol lond requirementfor the grinding unit is only 5hecfores, obout 2.5 hectores oflond need to be ocquired only forroilwoys. The plot size for theroilwoys olso becomes odd {Approx50 m wide x 1500 m longl. In ourrecent proiects we hove Foced lotof problems on this occount.

roil trock {Exit trock} through owogon troverser where pushereiecting out empty wogon fromtroverser to exit trock. The enclosedorrongement drowing ondphotogroph shows functioning ofwogon rroverser.

The wogon shifter works ol the

some speed os the wogon lipplerond bofh these equipments workin tondem. This woy the spoce

Wagan lraverusr {$htr?e$

requirement for the roil trocksreduces to qlmost holf. However,one porollel roil trock needs beconstructed besides the trock forremovol of wogons.

Expected benefitsr Sovings in lsnd cost qnd veriiqble

size of plot.

Benefits of wogon lroverser oreusuolly cose specific, ond in someof the coses, its inclusion could helpthe unit greotly.

Authors

Jal Ffe,t#sft Gupf*,is warkitlg as QhiefGefisral lt$afieger, withHALTEC CansultingFrivate Ltd. l4e has donegraduatian inMecfi :wr'dal engrneerlngtrom 8lT Mesra in 1982and later tu184 througltcarrespandence. He

kas over 32 yrs af experien*e and hasb*en with H3LT€C 6inc€ t995. He hasi:*en respr:n$ibfe fur execllfion of nanyseffient projecls f ram e onsept foc*mmissianing" tle has wide escpasure toprcjects sufside tndla, ineluding ifiVietnam, Az*rbaijan, Ffhicpia, .SaudlA{ebia, Fakisfen, Li$ya, Mang*lia etc.

Pradeep KurnarMittal, is w*&iftg as ChietGsneral Meneper, withH}LTgQ Q$nsultingFryale fid l4e has donegraduatian ifi Mechanica]engineering with post

,grsduaffbn in Suslness.; Atlministrati*n. Ile Flas

pver $9 yrs of *xparien€e afid has besnwith HOLT*.$ sinee 1982. t'fe has beenr*sponsible for Fusiness dev*lopment foreansulting assigrrnents, exeeutian afrfiany cement ptant rclated cansultingessigtnrnenfs reJaled fo feasr&iJrdy stodies,due diligen#, $\a{keting, i:f€ systern$, a$well as sfud/'es {at ather "5€clars, in lndiae8 wetl as in ather aauntries like,Switzerlafid, Uganda, l'lungary, China,AlEaria, Atrgeria, UAE, Sanglad*sh, lrary,

frenrnark, #hatan etc. tr

Figure 4: Typical Arrangemenf

To tockle this issue one of thesupplier's for wogon tippler, comeout with the sofulion of wogontroYer3er, immediotely sfier thewogon tippler. Keeping in mindthe limiiotions of lond ondconfidence on designs, the wogontroverser ore being instolled in oneof Holtec prolect.

After the wogon is unlooded onwogon tippler, side orm chorgerploces empty wogon on troversertoble, wogon is shifted to onother

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