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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‘
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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‘
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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
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11 Grosvenor CresCentLondon s、Vj X7EE EnslandTe1ephone OI 245 9744T。lex261700
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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
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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”"″
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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`‘
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tc
3‘3
r,."‘
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``(J(汝
沏 P`山c″ c厂 订油` Frs″ ‘J¢ z”
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c¢ /t初氵亻 太/,`η小`″
″
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
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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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