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Contents协 r Vo1ume ll∶ Nulη ber7 septelη beΓ 1980 IssN O30B-8855

A"v ews expressCdin th sjournal aretho$e of rcsoeC1ive

Con1ribu1ofs and are no1neC6sari y the opinions o∫

l杌 publishefs

subscopt。 n扌 a1es∶

^跏ua1subser p1ion

￡】O inCludiog postage

$25in Canada and UsA

321 De⒍gn of controI and monltori"g sys(ems lor SVng shin Cement’ s Dodam PIant刀 Ⅱ0″/tqc`夕 ,a‘

`万五,ss`

Ed:,o″曰`o汾

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WeXham springss1ough sL36PL Eng〗 andTelephone∶ Fu⒈ner2727Te1ex848352

ε山f●,'∶ 330 Ercct。f oxidic composition on Port!and cement ra、 Y meaI buruability

Paul V Maxwc⒒ -Cook s 彳乃‘Ⅱ‘

^'〃

〃勋`″

〃r /Dr〃c`

33, Roner miIls in dry grinding circuits

R C l/ci`扌 s

344 sucz CemeⅡ t CoInpany’s ne、v cement Plants wnI boost Egypt’ s construction industry

莒叩扌〖f+俨″岬″ 环 Ecuad。rs tementsho"age ω berdk、ed” new dant血 the Andes

353 Some interes‘ing featVrcs of precaIGi"iIIg systen1s

万c″gs Jˉ 9″

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11 Grosvenor CresCentLondon s、Vj X7EE EnslandTe1ephone OI 245 9744T。lex261700

爿ge″

`Jor刀〃s``′0 Ge″″曰″y

A。山″扫赫 s”〃z〃 /oz〃 ∫

Intermedia Part^ers GmbHLudw g Uhland s】 r7

369 New 1500t bu1k cement storagc and transfer compIex comρ leted

3,1 Better qVa1ify cements and energy saⅤ iugs~kcy themes of Paris Congrcss

37s InterlIat1onal News亠 Contrac‘ _Prqcc‘ s∫D5858Ennepe1a11Fede9a1Rcpubhc o∷Fede9a1Rcpubhc of Gcrnian●IelCohone O2333∫ 7600809耳gΨ 1艮lR艹∴1`q∞

:Φ 378 companx NellsTelex8592207dpwd

Designed and publohed by 381 Book RellewsCenlent and ConcrcteAssooa“ on

0W。 ild Cemcnt Technology

382 Plant amd Product`ews

PleViously Ccn△ ent Te山noIogy 390 IⅡdus“ iaI IiteratVrc receiVed

Pllnted by

踟 app‘ D氏wttt and sons Ltd 392 Ileaders’ service8乙 ngston upon Tha】nos,surreV

WORLD〔 EMt′ t TrCH`oLOGˇ sEPTFM⒔ LR 1980

some interesting features of precalcining systems

CEng,F〖^汀

echE,MAs小汪E PEng

PT 1ndoccIη ent, Ⅰlldonesia

Hcng S Tao,Bso,Group Chief Eng neer,

rntr。 duc(io∏

Th s is thc second part or a paper on Π /Ccns 氵″

CC″ C`〃

'勋`饣`印

d饣`而

″ J′氵r/s@l,Ic冖〃,,Cs`ltg忙 卩

`丨`rcso''厂 CC〃″仞ll g”、

`c`9Is w11ich was p弋senⅡd during

thc opcning cerelnony of the Sixth Technica1 sclu-

inar jn Plan1 0peration held on 10— 13 DeCCn】 bC1

1979, hl the Iηountain 1esort or Cisarua, BogOfIndonesia

The scmi11ar was Org[1nized by P T Distinc1Indon1)sia Cenlent En1erprisc, onC Of the member

Companie8ofIndocement Group,undeΓ the sponsor-

ship of AsOsi[1si Scmcn1ndOncsia It、 vas a11endCd by

nlorc than 60 Cngineefs, chcmists and teChno1ogists

fr。 m all six cemcnt Conipanies in l]ldonesia and、Ⅴas

high1ighted on the third day by flve papcrs pfesented

by guost speake1s 忄om 1he FedCral Rcpub"c OfCCrmanyandJapanspeCianyinvltGdbythcOrganizer

The guest papers were∶

1 H Herchenbach∶ △he H11n)boldt 、Vedag prc-ca1cining systGm Pyroclon

H 、Vuestner∶ Criteria goⅤcrning1hc sclcction of

cel△ ellt raw matef a1grinding fdcilitics

T Nisbida∶ Thc Kawasaki KSV SystemR 、Ve17∶ POlys us∶ 111omation in cclηcnt plan1s

G Hotz and P Kurpicrs∶ Histo ical dcve1opl△ Gnt

and outlook on rcliaCtories and technical dcvolop-

lnent in Celncnt rotary k"ns

KiIn CapaCity

If capital and nlarke1 aro not points of concern

、Ⅴhat capacity oF kiln 、vou1d you "ke to have roryouΓ nex1 ne、v p【 ant? The ans、 ver by a CemCntengineer l11ust bc.1|nanimously as large as p。 ssiblc!

1nt11c 1950s,a500tpd kiln 、Ⅴas a big kiln At that

tille a k"n oflO00tpd capac ty、ⅤasthC drCam of any

CCmcnt eng"leeI, and it、 Ⅴas unhCard of to consider

anytbing oveI 15OOtpd ln thc 1960s 2OOO tpd k"ns、vere considered 1arge as 、vcrC those 、vth cap11citie、

Of300O tpd in1he1970s,but1no、 v,30001pd knns arequi1e conlmon,and nany400Oto6OO0,even800O tpdkilns arc cithGr in ope1at On or under construCtion

Thc concern 、vith the mos1 efncien1 utihzation Offucl energy has led to 1oday s 、videspread accept-

ance of suspension preheatcr kiln systems^and1argef

k"n sizes Ho、Ⅴever, opGrating cⅩ perience has sho、Ⅴn

that as kiln diamcter jnCreascs, the kiln re订 ac1ory

life is rcd11ccd. resulting "l the decrease in kiln

avai1ability 1t has been found tha1、 Ⅴith a 1argc kiIn

diameter, the brick rillg streng111 is rCd1|ccd, and "l

W0【 LD CLM:N△ IECHN0I0GΥ s厂 P1rMBrR 1980

addi1ion the bufning7One has 1o absorb considcrˉ

ab1y more theInlalload,and the1ik orthc rcl actoryjining is th1】 s aiFected

I11 tbe past ten years 1hG l)rcCalCil lg pr。 cess ha`

played an innuentia1rolc in sOlving thcse problems

The preCa1Cini11g process incfeases decarbOnization

oFthe knn fted Ⅱ。m the usua140%1o abou19o%in 1be suspcnsion preheatcr, by 1he seCon(lary nring

lrom a pfecaIctn"lg ft1rnace ills1a11cd bc1`Ⅳ ccn thc

prchcatcr and the kiln in1ct As a rcsult, |ligb kiln

Capacity is attailled 、Ⅴith a giⅤ en k"n d 】ηcnsion, of,

、1 the sa∶ne output capaCity, the Iequi「 ed knnvolume o reduced by as much as50%Th沁 m[刂 of

innOvation llas almost doubled the k"n speci‘ ,c outˉ

put, b「 inging the k"n sizing into a ne、 v 1eYc1 oF

Ⅴolumc and output 「elationship For Gxam1)lC, a

46 dia × 70m knn wi1110ut preCaJcining wouldproduce about 20001pd, but can pfoduce 3400tpdOf more 、v th preCalCining Γhis corresponds to kiln

specinc Outpu1s 。f 206tpd m: and 350tpd m⒔Like、vise.a55dia × 8smk"n producing3500tpd、v thou1 prCCa1Cjn 1g can prod1】 ce 60001pd oI more,、vi1h prccalcin"lg

By burni1g a large ∶lnlo u n1 of fucl in a scpa1ate

f1rnace outside1he ki1n,thc thefnlal load in the knn

is considerably reduCCd,、vhich in turn inlproⅤ es the

refractOry ule and hGncc the k"n availab"订 y(Figure

” The sys1em a so afF rds lnany o1her adⅤan1ages,

whiCh wnl bC discussed later

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‘JIn sizC IiⅢitation

Considcring thc abrclucn1ioned 、atures iil k ln

dimensioniI1g is therc a lhuit to1ho ki1n size?、V th

the plesent ttelld(Figure2),it s ρossiblo that wi1hhl

f,ur tO6ve years, ki ns Of over 10000tpd capaci1y、vi11 be on the market and this is perfecuy△ asibIc

订oln 111e proCess poin1 of vie、 v B11t mechanicany

some assoCia(cd problems seem 1o lie in the nlanuˉ

facturc and transport。 ftbe k"n componcn1sKi n designers havc found that thc 、vcight of1hc

support ng mechanis1η "lcrea ses 1η ore sha1ply thanthe knn capacty For a 7O0O tpd kiln its carryi11g

r°ue[ 、veighs more than 20O1 、ⅤhiCh is lη ore thdn

1he CapaCi1y of mos1roundries in 1he、 vorld Even ir

this co11d bc manufaCturcd,its transporta1ion、 vould

st"1 bc a prob1Cm 1t Iuay not sCem so dilrlcu1t t。

n】anufaCtuIe k"n tyres of largc diameters. for thcy

can be made in split ring sections in the lnachilc

shop, and t1ssemb1ed 1ater on site Ho、 vever, dimˉ

cul1y exis1s 、vi1h 1hc tolcrancc bct、vcon a Very large

1yrC and thG k"n she",d1丨 c to the largG di「 rGncG in

hcat capacities of both parts Tbis tolerance must be

very p1ecisely detertη ined, in ordef to aVoid danlage

bejng caused during operation Inc。 rfect gaps 、v"l

fesu1t il k"n oⅤahty, 、vhich nlakes brick 、vork difnˉ

c111t Again, as explained earlier, the brick liFe that

has been preserved by 111e preCa1Cining Process 、viu

de1eriora1e as1hC kiln dialη ctcr incrcasCs

]§‘

Thc k1rge di1ulle1er ki1n she" secti° ns 、vou1d bedi1沂cu1t1o transpor1beca1】 se of1imitat ol、 s inlposcd

by harbours or roads This problem, ho、 vevef, llaay

be solⅤ ed by sitG-、 vclding mc1hods 、vhich haⅤ c beengaining p。 pularity in coun1ries where the quaIity of

、Ⅴelding is good and1abour is chcap

FΓ Olη the pract caI p。 int or viG、v,it、vo11d appear

111111 the nlaxi1η um ki1n diameter should rcmain、vi1hil1 61η under the present technical capabiljties

A 6m dia / 95m long kiln 、Ⅴith a precalcinef, fo1

instanco, 、YOuld llave a CapaCity of[1bout 8000tpd

PrecaIcining proCess

The precalC"ling procGss was nrst CxperiIllen1ed "l

Japan and the Federal RepubIic of Gcrn】 a11y in 1he

1960s, and has been developed il para11c1 in bothpar1s ofthe、 vorId1Ⅱ ldeΓ diiIerent circu1η stances

ln Japan the bu"dillg or large celnent plants at

CGntrah∠ Cd1ocations 1o Illee11he inCreasing denland

For cc1△ cnt has nCcessi1a1ed the design of rotary k"ns

of lafgc capacitiGs As Iargc diamctcr kilns becolη e

less a、 a lab1c.methods to incrcase the k"n· s speCiFlC

output have becotη e the centrc of research

In the Federal Republic of Cermany,however,the

original idea for adopti]lg the secondary hringpri∶ lcipIc、 vasto in1roduce a fue1-beariIlg r[1、v lη ateriaⅡ

io, oil-sha1e, 、vhich contai]ls a high Ilea1ing value,

scparatCly into thc s1|spcnsion l)rchGator for econˉ

onlical utjjzation the calcinatton of thc matcria1

、vith the burn"lg Ofr of its c。 mbustible lllatter in a

co1η bustion chamber at the bottom ofthe pΓ eheatcr,

resul1sin the po、sibi1i1y of reducillg1he k"n volun e

This spccia1apphcation Ilas1ed 1o ftIr1her kno、 Ⅴledge

and d1)vc1opm1)nts in prccalcining tcchniq1Ies

了hCrC sccms to bC a did℃ rcnt approaCh ill 111e

appIicatton concCpt of preCalc"ling processes bCt-

、veen Japan and thc FRG In Japan, the greatestpos“ ble po]“ on(50-70%)。 f the ltd′ burned in

1he prehea1er in order 1o a1tain the 11ighest speci】 ,c

k"n ou1put ln1hc FRG howcvcr,lCss attomp1isluadc to consumC motC f1cl at tbe prChGatGr, than

maintaining80-90:‘ calc lati。 n for ease of opefa-tioll It has been 1ea"zed that a high degree Of pre-

heater burn"lg may cause cloggiIlg in 1he Io、 ver

cyclone st∶ lge as(1res u11of the high1empera1ure rise

oF1he ra、 v]nea1,and iIlcrcasCd、Vastc gas losscs

RCsGarCh and 1)racticc made on botb sides. ho、 Ⅴ-

CvCr, havC 1)rovcd one con】 mon faCt——that the pre-

calcin lg prOcess is the tη ost suCCessful technique in

Ⅱηprov"lg the peΓ fc Γ1η ance of suspension preheater

kilIl systems

VaⅡous ρrCCaICining systems

l sf匀‘`c″

('愆〃c扌 )

J。inuy deve opcd by Ishikaw1nla~HaⅡ ma HcavyIndust1es Co Ltd and Ch chibu Cclnent CO LtdoF Japan,SF is the abbrevia1ion of Suspension F1ash

Calciller The nrs1 sF 、vas apphCd in a 100O tpdsuspen“ on pⅡ hcatcr knn(39m dia× 5137m)inCllichibu s No j works,and was comnlissioned inNovember j971 Eight months later,aFtef numcrousmodi6catiOns and improvemcnts, the system was

W0RLD C:MENt T「 C"`oLOGY s厂 PlrM8厂 R 1980

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based on 0noda’ s expericncc in thc hIη e-burning

pr。 cess in the car1y years,in co刂 uncu。 nw"h suspension preheater k"ns RsP is the abbIevia1ion of

Reinforced suspension Prehea1er The nrs1 RsPp"ot Operation 、vas eλ perimented in 0noda sTaha〗 a w。 rks,w th a18m dia × 28m klln,pro-ducing240tpd,in 1972 In 1974 thC nrst RsP kilnsys1em、 Vith a capacjty of2700tpd、 vas colη missionedjn 0noda Cemcnrs ofunat。 works The secondRsP knn(37m dia ×58m)was comm sg。 ned hl

Indoce1η enrs Cibin。 ng works hl lndonesia, with a

capacity or165O tpd,h11976

Raw meal descending仃 O lll 1he s1age-2 cyclonc is

6rst heated hl thc swirl ca1cher,in which C0⒉ is

driven of rapidly,and then dGscGndsinto the mix"lg

chalnber1o mee11hG asCcnding llot k"n g.lscs,、 VhiCh

Carry thC ra、 v mcalinto the stage-1cyclone,w hcre the

st spcnded ra、Ⅴ mealis calc"led.tnd separated,be亿 re

cntering the rotary k"n

'△〃`cJ s厂

s ,`″ ″

助 〃`〃

亻 ′sF‘J、`‘

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proved to be capable of producing200O tpd Basedon thc experienCC gaillcd in this operation, Chichibu

Cement convertCd one of i1s 、vct proCess knns(55m dia× IOO m),lt dle Kumagaya works hl1oan sF systcm in 1973, which aⅡ er commissioningproⅤed to be capable of producing7800tpd Ihis is

so far one of the Iafgest sF kj1ns in thG、 vor1d,usinga twinˉ to、ver suspcnsi。 n preheatef the kiln llas aspeci6c hcat consunlption of744kca∫ kg-c"nker

PreCa1Ci1】 ing is perfOrmed in a F1ash FurnaCewhich consists of a vortex duct at the bot1olη of a

rcaCtion Chamber, o1】 、VhiC11 1hree burnGrs are

insta⒒cd Ra、v mca1 desCends fro1△ the Centre in1ct

of the reaction Chamber 、vhcrc it mGcts the com-busting mixture of cooler air al1d kj n exit gascs

asCending仃 olη thc Ⅴ°rteX duCt in a stfong turbulent

n°w Thein【 lmate mixing and heat1ransFer betwecngases and ra、 Ⅴ mea1produces11igh ca1cina1ion be、 re

the ra、v mca1enters the knn

2R驴 sⅡ s泗99(ng〃`召

匆Tho sy“cm wasjo血⒒y dcvclopcd by0noda CementCo and Kawasaki Heavy Industries Ltd,of Japan. 卩仔W'j l’∫C9V″ ″

3 1,fFC s s`臼 ″Jlg″厂e∮)

Ano1hcr jolnt deVclopment th灬 ume by Mnsub、 h

HeaVy Industoes Ltd, and Mitsubishi Minitlg andCGmcnt Co Ltd OfJapan `Ι FC is1he abbreviatlon

of Mitsubishi F1uidized Ca1ciner ExPerinlen1s beganjn 1963 and 1he paten1 For thc MFC dcsign 、Ⅴas

obtained in 1968 In 1971. 卜1itsubishi Mining andCemen1adoptcd MFC in jts HigasInltani works,to a43m dia × 65m Dopol preheater k"n, 、vhich

easi1y achicved 2000tpd 、vi1h a 15ˉ month uninterˉ

ruptCd operation after Conlmissioning

The calc ning of raw mea1 is pcrforlned in aseparately heated nuid bcd rcactor insta"cd undcrthc

stage-2 cyClone R孙Ⅴ mcal is introduccd jnto the

reactOr and is nuidized by thc aeratio l air supplied

仃om ab1owcr whiCh draws hot a r flOm the c"nkercoo1er Thc nuidizcd 「a、v mea1 is ca1cined by 1he

heat gcnerated 9om burners nlOunted t1round 1hc

、Voκ LD C￡ MENt t〔 C"`oI OCΥ s(PT[MB「 R1980

蕊甜田艋投品 :ˉ~

358

n“″'6K” ,sjr″ ‘

Icactor be1o、v ",e nuidized bed surn1ce Calci11od

ra、V mCalis carried by thc combus1ion gascs into thc

s1agCˉ l Cyclone 、Ⅴhcre i1 is separatCd and enters the

kiln

4Ks'助 srf″t(ΠglIrc6)

KsV is the abbrcviation Of Ka、vasaki Spouted Bedand Vor1ex Chambcr,deⅤ eIoped by Ka、 vasaki HeaⅤ y

Industrios Ltd of Japan The l,rs1KsV was adopted

by Tokuyama soda Co L1d in 1973 for one of itscxisti11g suspcnsion Preheatcr kilns The convcrted

knn system 、Vas ProVCd to be capable Of producing3800tpd The1argcst KsV plesently in Opcration is

a‘ 2m dia× lO5mk"n system of Ube KOsan CoL1d,Japan It、 vas comInissioned in Apri1 1975, and

has sincc been operating a1an ou1p111oF85001pd

Consisting of fr ur zOncs,thC KsV furnace aCCepts

fa、v meal frOln 1wo stagC-2Cycl。 nes at t、Ⅴo separa1e

p。 siti° ns∶ onc at thC secondary air inIct duct, and

the o1her on top of the vortex chamber K"n C疝 t

gases are introduced9om the bottom ofthe fufnacG

and arc tfansformed into ∶1 ‘spouted Currenr "l the

spoutcd bed Mean、vhi1e 1he seCondary air being

dr孙vn iom the C1inkcr coo1Gr enters thC furnacetangentia"y1o凡 rm a ⅤorteX ii1the vortex Chanlber,

、vhere the spoutcd curlent and vortex ate miXed and

asCend into thc auⅩ iliary spout bed enroute to thC

mixing chamber B1】 rncrs plaCed at diJIerent posi-

tions spray ftlel into the Ⅴor1eλ chamber and the heat

produced is adsorbcd progrcssive1y by tbe highly

concentrated ra、 v mca⒈ and dccarbona1ion occursrapidly Ca1cincd ra、 v n△eal js separatCd from thc

kihl gascs in the stagc-1 cycl° ne^ before cntcring thc

k"n

5 D Jl sys`召″(∏gⅠ

``c7)A systcm joinuy deve1。 ped by Nihon Cclncnt CoLtd and Kobe stcc1Ltd ofJapan DD isthe11bbre、 △a-

1ion of Dua1Combustion and Dcni1ration FurnaceThe nr“ DD systcn△ Was adopted by Njhon Cementin19"in证s KamⅡ so works.ftr a3600tpd← “ m

W0i(LD CEMENT IECHN0L0GY s:V△ LMB△ 【 1980

da × 767m)k"n systGm,afler ga""ng opeIa"nLexperienCe wi1ha500tpd l)D knn at N"l。 n cenlcnrs

saeki 、Ⅴorks The Ka1η"so knn eventu〔

1lly reachcd

an o1tput of 3960tpd at a hea1 consun11Dtion of735kcaΙ∷kgˉ chnker

Calciling is perftirmed in a DD FurnaCC plaCedaboⅤ e the kiln in1et housing Ki1n cxit gascs cnter

diIect1y i]l1o thc f1rnacc 仃om the botto1η , 、VhiIc

prehea1cd combustion ail enters thc Ftlrnace订 om1hechnker coolcf via an ind11ccd air duct Ra、v mea1CntCrs the ftlrnacc仔om the side of1he furnacC just

aboⅤ e the burners Fue1 and gas arc thoro1ghlymixed in the aⅡer-burning zonC in thG uppGt part。 f

the fufnaCc,、vhere complCtC combustion is achicved

Ct11Cilled ra、 v mCal is brought "lt。 thc stage-1

cyc1onc、 vith hot gases and is separated仃 om the gas

strCam

6 '‘sP,cc″ c llf严 (F· gl Fc8)

The F L smidth Prcca1Cining sys1e]u has two indcˉ

Πg〃″ 8 ’iEs ●″″

′t″ c7DD”"″

″

pcndent suspCnsion prebcatCr IiI1cs∶ onG ConnCCtCdto thc k"n, and the odler conneCted to thc precaⅡc“er Λpproximate y40%ofthe law mea is fed tothe k"np1ehe扯 eΓ

"le,and the remain ng60%灬fed

to the plecalcillcr line Prehea1itlg or r11、v meal is

efIected by the ki1n exi1ga、 es, and preCalCiner con1ˉ

bus1ion gases.respeCtive1y.in the prehcater CyC1on1)s

Prehea1cd ra、 v mcal is i11troduCCd into thc prcca1ˉ

cincr,whGrG it is ca1cincd to90;。 by burncrs mounted

on thc lo、 Ⅴer1)art of thc precaIci11er cha1η bCf, and is

brOught 、Ⅴith the hot gas strean△ Ⅱlto the stage-1

cyclone^ 、vhere the calciIled ra、Ⅴ meal is separated

仃om the gases and entersthe knn In the FLS systenl,

60%Ofthe i】 el^burned in the precalciner.and tlle

lema nhlg40%burned in1he kiln A400Otpd FLSsysⅡm← 75m dia ×75m)was commlssloned jn1977a1Aso Ccmcnt Co s Iagawa works With a heatConsun△ ption of740kcal∷ kgˇ c"nkcr

Il tbjs design, the distribution of co1η bustion air

betwecn the k"n and precalciner is eas1y controlled

because ofthe t、 vo independent pIehea1er lilles TllG

hot[1ir fronl1he chnker coo1er being the onIy con1-

bustion air, 1hereFore 1he combustio11 i11 thc pfeˉ

ca1ci11cris co llplCtC and stable

7r、R″ rlI。rs灿″←`g〃

`e助Pol· sllls AG of`Vest G∝ many has developed twok而 ds Of precalc n ng systems PREP0L AT(ai卜through)and PREP0L As(Air separate) The ATsystem is part cu1ar1y no1e、 vor1hy as i1 is tbc nrst

prcCa1Cining systenl 1o dispense with thc tcrtiary ajr

duc1 connected bet、 vecn the Clinkcr coOler and thc

preheatGr

In thc A】 SystGm,the Cnt fe co1η bustiOn air no、 v`

throug11thc k"n, and calc"ling is performed iIl the

plecalcjner plaCed bet、 veen thc kiln in1e1 and 1Ilc

stageˉ 1 cyc1one Ra、Ⅴ mea1 is illtrod1ICed Ⅱom 1hcstageˉ2 vOrtex Vesse1 in1o 111e preCalCincr and is

calci]led by hcat‘∶∶en era1cd by thc burnGrs mounted()ll 1he10、 vcr part of thc prcca【 cincr duct Fof thcsamc dialuctcr, thC AT System llas a higher gas

Π甲i· , ’’尺「P0∠ 刀7o,v″″

ve|ocity in t11ek"n because of the 1argcf gas VoluluC

Conta""ng excess aⅡ ofabout12%Oxygcn HowGvcr,Opcrat ng cxpcriences have sho、 vn that this highGl

gas ve1oc ty does nOt aiIect the ki1n pefformance in

slη aller k"ns of11p to2000tpd For larger capac ties,

however,1he AT Sys1em requ沁 es about20%k1· ger

kih1diamctcrs Thc AT systcm can Ci1hcr be cquip-pcd 、Ⅴith a grate cooICr or a planctary c。 olCr Tlle

nrst PREPOL ΛT systcm was Ciments △aflrgc′ s

46nl dia / 75m kiIn cOn△missiOncd i1 1973 、vjth

a capacity of3000tpd the1algest AT system cuf-弋ntly in operadon is a4700tpd knn(52m da ×80m)a1Cementa AB s shte wOrksin Swedcn EaΓ ly

in1978a300O1pd AT sys1em(46m dia ※70m)Was suCCCssΓ ully commis“ oned a1 Aslan Ce∶ ηent

Co^s Darica wo∫ ksin TurkcyThe PREP0L Λs Systen】 has bcGn dcvc opcd wlth

a Ⅴic、Ⅴ to Iη"limizing the kilIl dime,sions by bufningthe largest possible atη ount of fllel in thC prccaICinGr

and the smanest possiblc fuel supply to the kiIn, or

to produCing1ow a1kah chnker by bypas“ ng30%orl11ore k"n gases The flrs1PREP0L AS Sys1em wusbuilt for TGxas CcrnGnt Co in d1e UsA in1978,and

the largest AS k"n under construC“ on is a541u dia

× 80nl knn 、Ⅴith a capacity of7000tpd i】 sout11

K orea

8Py尺 0CE0Ⅳ 助src`″ (∏g〃严召′0)The Humbo1dtˉ 、Vedag PyrOclOn system 、vas deVeⅡ

opGd by KHD Humbo1d1 、Vedag AG of、 Vcst

GGrmany,bascd on its many years of know-ho、 v and

eXperienCC accurnu1atGd in suspension pre11ea1ersTwo PYR0CLON sy哎 cms arc bCing markc1cd∶PYR0CLON-R whlkh ut"lzes j1ot air from thcclinker coole∶ as c° m bus“on aif,w止 h30to70%k)ta1nIing rates atthe preca1ciner;and PYROCL0Nˉ

S, to 、vhiCh the combustion air is supplied through

`ls〃

″c`nP】∴Ro cE0VR灬^`c″ `

WORL0CEMε Nt I:CH`0LOG、 s⒈ plrMRε R 1980

the ro1π y knn,with nong rates of up to40%Ihe6Ist PΥ R0CL0N knn flrcd w止 h oi1shale,camc into

唧lI∶l;抵黥 ~扌J骆。mu。n、⒚、rm讯

:∶I诘:∶乳喋:淞T扌l茫〖找脊l志·揣怼雀

刂烈⒒J廾 r扌‖i岁带。艹摧‰淞找盅扌紧垠tl;祗博苜b踹 ,携 kl11诎撺I:lsi;∶:ll:;∶

ra、V meal tha1 has been preheated to the ca1Cining

槲 ⒎拊晶擀燃 r繇conlbus1ion heat genGrated is transferred onto the

fa、v mea1、vhne i1is being picked11p by thc k"n and

c。 mbustion gas s1rCalnl no、 ving in strong turbu1encc

糕 甘 、濯 l℃ l::;∶氵l器脾 苄 ℃ $l咒In 1hc passage ra、 v tη eal is 、vell n1ixed 、vith gases

and is calcincd to 1ho desired 1evel Tlle nrst

PYROCL0N-R syste1△ was commis“ oned in1977

lndocements No 3knn(46mdia x70m,cap

燕酣甜胛ξ菇撼薮莒谐辅b觜

1裟F雀糨岳;I$m:砉古18:L。 MseⅩCept that the Combus1ion air passCs through thc

ro1ary knn T° achieve complctc C0mbust on in thc

社翟嚣哏眢3盆:埔几{⒒器llⅠr栋湍to tbe a]uoulnt of fucl being burned in 1he preca1-

ci11eI It has been found tha1in this sys1em the gas

veloci1y ins de the kiln should not exceed 14n∫ s in

Order to prevent dust circuits bct、 veen the rotary

ki1n and preheatef For capaCtties less than2500tpd,

howcver,PYR0CL0N-s is pIeferred on the basis oflcss equipmcnt cost The6rst PYROCLoN-s killl

滞 1a罗 斜 扰 巴 {∶∶{∶∶|∶∶∴Ι

s∶

|∶!|∶ |丨

:|丨

∴iE揄舻

PaItial precaIcining

For CXjsting suspension prchcater ki1ns,it is possib1e

1o insta11burners,at an en1arged⒒scr duct bet、 VCCn

1hc stage-l cyclone and the knn inlet, to ca1Cinepart ally the ra、Ⅴ 1△eal beftrc it cntcrs 1hC kiln

轷 扌 r乍 △ 毋骟

黜 ∵犭 f蹴 揣

。utpu1 inCreasG is res1riCtcd duc 1o Ⅱmitations of

assoCiated equipInent, suCh as capaCitics of ra、 v

grind Ilg lnil, clinker coolcr, or transport systems,

and such J讠 kc, the substantia1 reduction in therrnal

load iIl the sill(ering zonc of thc knn can gcatly

eⅩtend the servicc |jfc Of thc refⅡ actory1illing,、 vhiCh

in turn jmproVCs tJnc runni1】 g factor Ofthe kiln pla1】 t

Partial preCalcining may s"~。 htly inCreasc the pre-

hcater exit gas temperature, but it shouΙ d not be

bcyond tI1e exbaus1 fan’ s bandling 垃mit, and thc

W0RLD Cr、 1ε

`r rrc"`oL0GY sⅡP【 ⒈、1‘ 1k l’ 80

′饣Ⅲ?″ R″`汩

′``'.rIt勋

氵皙

additional heat should be ab1G to be utlhzGd in ra、 v

matcfial drying

Existing suspension prcheater ki1ns can a1so bC

modi6ed 、Ⅴith the installation of an add tiona1pre-

heater linG、 vith precalcining,as sh0、 Vn in Figurc12

Th0mcthod can incrcase knn output by up to lO0%and bccausc ofthe sepafatc ereCti0n ofthe prcheatcr

line during operation,do、 vn1imc is minillizcd for the

intcgfat on of thC system In addition to thc cxtra

凇岈扌Ii拣c%时社h乩掠i找s肾嘿躁inⅤcstigated, and the cooler capacity improved

`lg```饣

′2 彳/rl汩``“

``,。

t‘k″氵``mg/i`‘

”红〃″`″

tc

3‘3

r,."‘

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Preheater bypass

Excessivc amounts of potass um, sodi1m, su1phurand chloride compounds which becOme volatilizedand vapourized in thO burning zOne of a rotary kiln

Cause operatio laI prob1c1η s in 1hc suspension prG-

heater

In a 、ve1 proCess Or long dry process k"n, these

Ⅴapourized chemica1s 1cave the kj1n 、Ⅴith the exit

gases throug11 the stack But in a suspension prc-

heatcr kiln, because of the intimate gasˉ to-material

contaCt in tho preheater, 1hc vapours condense on

the ra、 v111eal particIcs、 vhen reaching lo、Ⅴcr temPeraˉ

tures, and ",ercforc cannot esCape 、vith thc gases

through the preheater ∷Ra、v n1ea1 particIes 、vith

Vapour Condensat ons、Ⅴnl adhcrc t° 1he insidc、Ⅴalls

of1he cyclones and ducts and form so1idined bund~

ups A1kahes and su1ph ur,being partia11y vo1at"ized

in thc burning zone, 、Ⅴi11 eventuauy lcave 1he knn

in thG chnkcr Ch1orides, 11aⅤ ing becn vo1atilized in

the burning zonG and rGCondensed in thc prcheater,continuc to be Conccntra1ed Thcse obJcctionab1eCompound8 fortη an intCrnal recircu1ati。 n cyclC inthc k"n system,assho、 vn in FigurG13

Furthermore, if thc ra、 v ∫naterial contains bituˉ

minous substances, such as kcrogcns, Coa1ˉ shale,

oil^sI1a1G and such 1ike, Overheating occ1】 rs in thc

uppCr stages of1he prehea1er

The Follo、ving problcms arc caused by an thcse111desirab1e chemica1s∶

(a) Poor c"nker quality duc to excessive quantity or

∶t1ka1i

(b) B1"1d-ups and cloggings caused by GxcessiⅤ e

quant ties oFalkali.ca1ounn sulphates or Ch1orides

i∶l thelo、vcr stages ofthe prcheater

C)0vcfheating in the upper stages of thG preheaterby the combustion of bi1ulη inous ra、Ⅴ ma1eria1s

To oⅤ erCo1△ e1hese problems,a bypass system must

bc usod ‘o diΥcrt par1 。f1bc knn gascs, befcrc thcy

a‘4

enter thc preheater^ into a separate 、vastc gas-handhng system c° nsisting of an air qucnch cham-bGr, coo1ing air fan, dust co11ec1or and exhaust fan

I·lgurC14sho、Ⅴs a typica1bypass arrangement lvlth

a suspCnsion Preheater equippcd、vith a precalciner

T° avoid f。 rnlatiOn of build-ups caused by thevapourized compounds and alkaΙ i-ladcn dust, thebypass gascs m1s1 be imInediately quenChed bycoo1ing air upon 1Gaving the preheater duct Ihegases, being co° Icd down f1oI】 1100°C to abou1450·C, w"l i1rther bc c。 oled by water spray toabou1 28O·C, befole cntCring the dust co"cct° r

thc percentage of kiln gas bypass quant汪 y s

determinGd with regard to the approp五 a1e1o、vefing

of the conccntrations of chloridcs, sulphates anda1kalies, both in the prcheater system, and in 1he

outg° ing clinker.in such a 分act on that thc prob-1ems wnl be rcduccd to an unharmftl1cve

1fthc bypass is on1y intended For thc reduction of

o旬 ec6° nable chcmicaIs to c1imin,lte p1ehcatcr c o⒏

ging prob1ems,° nly3t。 5%bypass may su质 ce

Thc cqulpment costs孙 r such instal1ations ale not

very CXpenslve

In North A1△ erica, 、Ⅴhere cement users demandthat thc aⅡ o、vab1e a1kah cOntent in cetnent be less

than O6%total a1ka1ies eλ pressed as Na20讠 q uiv-

a1ent, 1η uch larger bypass systems_ˉ in the rangc °fI孓JO%— haⅡ to bt· “∞ siⅡ e u1。 b,lla、 wstemhand1es lligh tclη pefaturC gasCs in1arge volumes,thc

inⅤ Gstment Costs fOr thc instanati。 n arc Considerably

higher This wlll be assoCiated ,itb substantia【 llea1

and dust losscs practica1operation experienCcs have

reveaIed that for evcry l% of ki1n gases bypasscd,

the hcat losses 、Ⅴould bc 5-7 kca1∫ kg clinker, andthc dustloss would bc0j5~020%

When a pⅡ calc1ner js cqull,ped t0the pleheater,

abou1on1y50%°f thC gases passing dlrough thepreheater comc △om the kiIn, thcrCft,re, a m1】 Chsmaller bypass is required to attain the same errec1

、~0RLD CtMtNt t[C"N0L0GY sr1T△ “ ⒔⒈ 1 1,80

Fi甘△″c`j``‘ 〃伐″″〃竿("氵

"“c″ "″”′0· %j丿

`″

、̀

EXpGr"η ents haVe proⅤCd that w th a inrCCalCiner

burning 、vi111 |、 es11 conlbustion air rccoⅤ cred frotη

the clinkcr coolcr,it is plactica"y possible to bypass

100%or1hc kdn gases(F guR15)Th。 。 paΓucularIy usCfuI for p ant、 wnh dimcult raw material、 oI

ftle1cOnditions

UtiIiza(ion ofIo{gIadc ilIC1s

Rising cnergy cos1s havc pronlpted cenlcnt n1an1-

factul e1s tO lOok for altGrn.ltiⅤ e、 tO heavy fucl od

Coa. 、vhich had bGcn almost exc111siⅤ G1y 1scd fOr

nting the rotary k"n l the ear1y days, has been

nlakilg a Conac-back il the conlont h9d11stry

Althougln coaI nf t)g lla、 bcCn ado atcd by suspension

prehcatcr kiIns n)ral。 ng 1imo tl)c in tial design or

1hc precalcin"lg sy、 tCnl 、vas based On the use or oi

as fuel Consequcn1】 y many eⅩ pertη ents have bCCn

lllade ill Γecen( yCars 、vith tegatd to the app1ication

of pulⅤ erizcd coal fof conlbust o l in 1he prCCa|Cinef

ExperienCC has ptOved tl11t buInillL· high gradecoa⒈ or naturaI gas, il a llreca1cillcr docs 11ot p。 se

1Oo n1uCh Of a probleln B111 thc usc oΓ lo、V gtade

coa1of b tunlin1)us ra、 Ⅴ llla1Cfials such as O s̄hale

Coal-shale,and 1he1iko ca"s for special llandl ng1uld

trcattη ent tlle il1】 portant aspects "l buΓ nilg 、uCh

fuels "l t11e preca1Cining systenls are the cOn1ro1 of

f· ed quan1i1y 1hrough tle bufneI、 t1nd 111e Con1rol

Of fue1quahty1crGrf l、 g to its llonlogenei1y in ordcr

to mail、1ain a cOn、 tant he111 illpu1 h)1o thc prGcal-

cillcr tbcrcby ensur lg s1eady ki n opcra|ion

Hor so"d fue1、 、uch as thOscjustlη Cnt onCd feed-

ilg can be eI讠 oc1cd by lllcains of precisiOn 、veighing

de、 ices H()wevcr 1o aCConlplish constant nOW or

heat i】 l1o 111C prGcalchncf, the fuel ha、 to be 、ven

blendcd dricd and 狗nely pulvefized, be|、 re bcill(∶:

doscd into thc l)i ecalc"leΓ such go[11s Can bC achicⅤ cd

wi1h thc use of st∶ tckerˉ rec1[1mcr equ ηηcnt, al,d a

bo、、丨-o↑ ba"ˉ 1ypc coal lη i11 a" of、 vhich ha、 c l)cen

、vc" de、 elOped and arC rcad"y adOptab丨 o l the

indu、tΓy The pu1vcrizcd ilG丨 cal eitheΓ bc hltΓ Oˉ

、V0tLD t⒈`⒈

\【 【⒈←"`oLo〈

Υ `∫ 】l⒈

`Bl` |,‘0

duced into thc prcca1ciner by mechanical f· 。edin g

systcm. or pncunlatic sy、 ten1, e gⅡ Via air blo、 Ⅴcr

In practice. lo、 v qu∶ 11i1y coa1 of bitu llinous fa、 Ⅴ

n1,lteri.il can be utihzed for prGcalCining if the fore-

going j)rincip1e i、 obserⅤcd ∶Γhc lo、v tetη peraturc

cOlη bustic× l in1he preca1cincf does t、 Ot set any1o、 Ⅴer

nlit to 1he ca1orinc va111c ofthc∩△el Thc lestriction

being 111e asI1 Contcnt "l the fueⅡ 、vhich llas to be

1aken into account as part of 1he ra、 Ⅴ n1ea1 、Vhilc

dcsign"】 g che1η ical composi1ion oΓ thc ra、v miⅩ

Suh"9ur in the fuel、 vnl]l。 1l’ rCsCnt probIems at lo、 v

tClll pefat11re buIniIlg, b1t it 、vdl be absorbed in thcra、v nle.tl and luay ap、ct thc knn

the、 e nla1eri∶ 11s can cithCr bc buΓ tled in t11e pre-

calciner、vi1h Co1△ bustion ail fΓ otη the chnker coolcr

or1hrough thC rotary knn Il the1atter casC, bC1tcr

Fue1 econo l y is achie、 ed R)r 1he sa1】 c dcgrcG ofc111cillation, duc to higher tempera1urC of t11c co1uˉ

bustlon aif bcilg l)rehea1ed in1hc k"n

Ihc allount Of a、h in1hcso fucIs.凡 rnl lg part or

thc ra、Ⅴ |n〕 eal be lg+ed dircct1y into thc pfecalcineI,

、Ⅴ"l reduce the degrcc of hcat recOⅤ

ery f「 Ol△ 1he

k"n exit g[1、 es iI1 thc prehcatcr Tlli、 res u11s ill an

increasc in prchcator exhaust gas tempera1urC

l∶ i、e-stagc ρrCheater

When high dCgrcc of pΓ ecJon ng(95°

`is1hG"ghcstpossiblc lcvcl achievablc ill 1oday s tcchnolOgy) is

leq11irCd thc exhau、 1 gas 1elupcrat urc "lcrcases

aCCording|y If the、e ho1 gascs arc not ut"ized r。 r

ra、v lllatetial dry l.: a nlth stagc cyclone may be

addcd to Γed11Ce unnCCCssary lleat losses

I)lc|leatel sys1cnls 、Vit11 fue bear"lg It1、Ⅴ rnatCrial

beiilg "l1rod1|Ccd into thc lo、 Ⅴe「 cyc1onc stagC to

a"O、v conlbus1ion,caus"lg c)Ⅴ crˉ hea1iIlg in thc1】 ppef

sta】|∶

es, Can also use a nftll st∶ 1gc cycIonc to obtahl

nlOre hCa1rCCOvery(Figurc 16)

A nnh stage cyclOlle Can a1sO be added, 、vhenpar1ia| |)rCcalcining[1dol)1cd by an eⅩ isting prehea1cr

CrCatGs excessive exlla11st gas tenlperat11re

′I″ c∫‘'"←

‘̌刂c``c” ″′冖"″

^〃“〃″″洄

365

`Vith additiona1hea1exchangc in tbc nfth cyc1onestagc,the6veˉ stage suspcnsion prchcater can red11ce

lleat con8ump1ion of thc k"n system tO as lO、 v as

720-740kca1∫ kg c1inkcr, but thc cⅩ tfa cyC1one stage

increases pressurG Joss acr° ss thc preheater. 1hus

pena1izing the po、 vef consunlpt on of the system T。

alleYia(e this pfoblem, extensiⅤ e researCh has becn

made by many k"n Tanufac1urers in the devcIop-ment of lo、v pressure-1oss cycloncs 丁he usc ofhorizOntal cyc1ones is one of thG innovations in this

neId,which yie1d on1y about50%of the p门 ssure

lOss of the convcntional typcs of cyc1ones Byrep1acillg1、 vo stagcs of Cyclones、 vith()ne horizonta1

cyc1one 1he tota1 pressurc loss of a 6veˉ stage pre-

llea1er can rC1η ain at thc salη e Ievel as a f ur-stagc

preheatcr

Conelusions

BasGd on thc foIegoing ft· aturGs of pfecalcining

systems and their theoretical and pfactical itη phca-

tions, t is safp to say that thcse systelη s proⅤide

unfailing beneflts in today’ s pyro-prOcessing tech-

niques More and mofc precalcining preheater kilns

ale being built throughout thc、 Ⅴorld in prc△ rGncc to

any othCr process pfesently aⅤ aiIab1o Connrmedadvantages ofthe preca1Cinillg sys1e]u inCludc∶

(a)Improved kiln ava"abili1y(b)Reduced re仃actory Consuluption

(c) Increased ki1n specinC output

(dl Lower Noxemis蚯 ons

e)steadler knn operation(f) Less heat1osscs with bypass system

佗)MorG compaCt plant de“ gnThe unitcd states ccmcnt manuhC1urers arc

particulafjy Ⅱlterested in thc preca1cining systcms、vhicj】 afe ablc to Oi+er 1o、 v a1ka1i cGrnGnt to rnect

const111ctional requirelnents, and 1o、v NOx emisˉ

siOns to comp1y 、Ⅴi1h thc cnvironmental protection

regu1ations

Aspects1hat may bc considefed disadvantageous,

or arCas 、vhcrc improⅤ enlcnts arc required, iI1

opcrating such systcms arc∶

伍)More contro‘ requi弋 d bccau￡ of mole burners

Φ)M°rc atⅡ lltion nceded to proper dlsthbution of

seCondary aif and tertiary air

(c)Clogging potentia1a11ower cydonc stage due to

hightemperatureriseinrawlllCal(d)H瑭 hef prehcater exhaust gas temperature when

bu∶ ning high-ash so1id fue1s

RLrEREN cEs

l A`DI双、o、 ,K l KiIn selec1ion FEA PCΛ sen)")al("1LnctgyM:垮

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GTb艹19飞∫JI育4&c。

R ec。 nstrucuon of Λs。 ccmcnt Co s

摁 °茁l抚 in Japan``ith a40001pu pI℃ calcining kiln FI s

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