1.2 MPTPAPP

PLANTPROCESS OPERATION& CONTROL

AREA:INDURATION

PROJECT: 1.2 MTPA MT PA PELLET PELLE T PLANT

FOR  Client:

M/s:M/s :- JAYA JAYASWAL SWAL NECO INDUSTRIE INDUST RIES S LIMITE LIMITED D

Consultant:

M/s GANG ENGINEERING PVT LTD RAIPUR , C.G

Page

Revision . Date! "an. #$! .%&#

Table Table o Co!"e!"s 1. Introduction............................. Introduction........................................................ ...................................................... .................................................................. ....................................... 2. Induration Process Review............................. Review........................................................ .......................................................... ............................... .......... 2.1

The Indurating Indurating machine............................ machine....................................................... ...................................................... .......................................... ...............

2.2

Proce roces ss Area reas , Process Fans.................................... Fans.......................................................................... ...................................... ............. ............ .

2.3

Material flow through the machine................................ machine........................................................... ................................................. ...................... 2.3.1 2.3.1 Drying... Drying........ .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... ................. ................. ..... 2.3.2 2.3.2 Preheati Preheating.. ng....... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... ................ ..................... .......... 2.3.3 2.3.3 Firing... Firing........ .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... ........... .................. ........................ ............... ... 2.3.4 Afterfiring.............................. Afterfiring......................................................... ...................................................... .................................................... ......................... 2.3.! 2.3.! "ooling "ooling in the 1st cooling cooling #one... #one........ .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... ................. .............. .. 2.3.$ "ooling in the 2nd cooling #one.................................. #one............................................................. .......................................... ............... 2.3.% 2.3.% Machine Machine Discharg Discharge... e........ .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... ........... ................. ........... 2.4 &as flow through through the machine. machine...... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... ........... ................ .......... 2.4.1 '(er(iew............................... '(er(iew.......................................................... ...................................................... ..................................................... .......................... 2.4.2 2.4.2 Primary Primary Process Process &as )tream.. )tream....... .......... .......... .......... .......... .......... .......... .......... .......... .......... ................. ........................ ............... ... 2.4.3 )econdary )econdary Process &as )tream................................... )tream.............................................................. ........................................ ............. 2.4.4 2.4.4 'ther 'ther Features Features of the Process Process &as )ystem... )ystem........ .......... .......... .......... ........... .................. ........................ ................ ....

3. Control Review.............................. Review......................................................... ...................................................... ............................................................ ................................. 3.1

'*erating Modes................................. Modes............................................................ ...................................................... ............................................... .................... 3.1.1 3.1.1 +ocal +ocal Mode... Mode........ .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... ............ ................... ............ 3.1.2 3.1.2 ,emote ,emote Mode... Mode........ .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... ................. ............... ... 3.1.3 Manual Mode................................... Mode.............................................................. ...................................................... .......................................... ............... 3.1.4 Automatic Mode..................................... Mode................................................................ ...................................................... .................................... ......... 3.1.! 3.1.! "ascade "ascade Mode..... Mode.......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... ............... ...................... ..................... .........

3.2

Princi*al Princi*al "ontrol "ontrol Mechanis Mechanisms ms in the Induratio Induration n machine..... machine.......... .......... .......... ............. .................... .................. ...... 3.2.1 &rate )*eed and -ed De*th................................ De*th........................................................... ................................................. ...................... 3.2.2 ood Tem*erature Tem*erature Profile.................................... Profile............................................................... ................................................. ...................... 3.2.3 3.2.3 -urnthro -urnthrough ugh "ontrol. "ontrol...... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... ................ ..................... .......... 3.3 )econda )econdary ry "ontrol "ontrol Mechanism Mechanisms s in the Indurat Induration ion machine... machine........ .......... .......... .......... .......... ............. ............... ....... 3.3.1 "ooling Air Flow......................................... Flow.................................................................... ........................................................... ................................ 3.3.2 3.3.2 /*draft /*draft Drying Drying 0indo 0indo Pressure Pressure..... .......... .......... .......... .......... .......... .......... .......... .............. ..................... ....................... ........... 3.3.3 /*draft Drying Tem*erature... em*erature.............................. ...................................................... .................................................... ......................... 3.3.4 Downdraft Drying Tem*erature.......................... m*erature..................................................... ................................................ ..................... ... 3.3.! 3.3.! 0indo 0indo haust haust Fan Flow..... Flow.......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... ............... ...................... ............ 3.3.$ 3.3.$ Downdraf Downdraftt Drying Drying ood ood Pressure Pressure..... .......... .......... .......... .......... .......... .......... .......... .......... .......... ................. ....................... ........... 3.3.% 3.3.% /*draft /*draft Drying Drying ood ood Pressure Pressure..... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... ............. ........ 4. Operational Operational Review.............................. Review.......................................................... ....................................................... .................................................... ......................... Page

Revision . Date! "an. #$! .%&#

Table Table o Co!"e!"s 1. Introduction............................. Introduction........................................................ ...................................................... .................................................................. ....................................... 2. Induration Process Review............................. Review........................................................ .......................................................... ............................... .......... 2.1

The Indurating Indurating machine............................ machine....................................................... ...................................................... .......................................... ...............

2.2

Proce roces ss Area reas , Process Fans.................................... Fans.......................................................................... ...................................... ............. ............ .

2.3

Material flow through the machine................................ machine........................................................... ................................................. ...................... 2.3.1 2.3.1 Drying... Drying........ .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... ................. ................. ..... 2.3.2 2.3.2 Preheati Preheating.. ng....... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... ................ ..................... .......... 2.3.3 2.3.3 Firing... Firing........ .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... ........... .................. ........................ ............... ... 2.3.4 Afterfiring.............................. Afterfiring......................................................... ...................................................... .................................................... ......................... 2.3.! 2.3.! "ooling "ooling in the 1st cooling cooling #one... #one........ .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... ................. .............. .. 2.3.$ "ooling in the 2nd cooling #one.................................. #one............................................................. .......................................... ............... 2.3.% 2.3.% Machine Machine Discharg Discharge... e........ .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... ........... ................. ........... 2.4 &as flow through through the machine. machine...... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... ........... ................ .......... 2.4.1 '(er(iew............................... '(er(iew.......................................................... ...................................................... ..................................................... .......................... 2.4.2 2.4.2 Primary Primary Process Process &as )tream.. )tream....... .......... .......... .......... .......... .......... .......... .......... .......... .......... ................. ........................ ............... ... 2.4.3 )econdary )econdary Process &as )tream................................... )tream.............................................................. ........................................ ............. 2.4.4 2.4.4 'ther 'ther Features Features of the Process Process &as )ystem... )ystem........ .......... .......... .......... ........... .................. ........................ ................ ....

3. Control Review.............................. Review......................................................... ...................................................... ............................................................ ................................. 3.1

'*erating Modes................................. Modes............................................................ ...................................................... ............................................... .................... 3.1.1 3.1.1 +ocal +ocal Mode... Mode........ .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... ............ ................... ............ 3.1.2 3.1.2 ,emote ,emote Mode... Mode........ .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... ................. ............... ... 3.1.3 Manual Mode................................... Mode.............................................................. ...................................................... .......................................... ............... 3.1.4 Automatic Mode..................................... Mode................................................................ ...................................................... .................................... ......... 3.1.! 3.1.! "ascade "ascade Mode..... Mode.......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... ............... ...................... ..................... .........

3.2

Princi*al Princi*al "ontrol "ontrol Mechanis Mechanisms ms in the Induratio Induration n machine..... machine.......... .......... .......... ............. .................... .................. ...... 3.2.1 &rate )*eed and -ed De*th................................ De*th........................................................... ................................................. ...................... 3.2.2 ood Tem*erature Tem*erature Profile.................................... Profile............................................................... ................................................. ...................... 3.2.3 3.2.3 -urnthro -urnthrough ugh "ontrol. "ontrol...... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... ................ ..................... .......... 3.3 )econda )econdary ry "ontrol "ontrol Mechanism Mechanisms s in the Indurat Induration ion machine... machine........ .......... .......... .......... .......... ............. ............... ....... 3.3.1 "ooling Air Flow......................................... Flow.................................................................... ........................................................... ................................ 3.3.2 3.3.2 /*draft /*draft Drying Drying 0indo 0indo Pressure Pressure..... .......... .......... .......... .......... .......... .......... .......... .............. ..................... ....................... ........... 3.3.3 /*draft Drying Tem*erature... em*erature.............................. ...................................................... .................................................... ......................... 3.3.4 Downdraft Drying Tem*erature.......................... m*erature..................................................... ................................................ ..................... ... 3.3.! 3.3.! 0indo 0indo haust haust Fan Flow..... Flow.......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... ............... ...................... ............ 3.3.$ 3.3.$ Downdraf Downdraftt Drying Drying ood ood Pressure Pressure..... .......... .......... .......... .......... .......... .......... .......... .......... .......... ................. ....................... ........... 3.3.% 3.3.% /*draft /*draft Drying Drying ood ood Pressure Pressure..... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... ............. ........ 4. Operational Operational Review.............................. Review.......................................................... ....................................................... .................................................... ......................... Page

4.1

)tarting )tarting /* the Plant Plant after a Planned Planned )hutdow )hutdown.... n......... .......... .......... .......... .......... ................. ........................ .................. ...... 4.1.1 4.1.1 ,outine ,outine "hecs... "hecs........ .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... ............ .................... .................... ....... 4.1.2 /tilities........................................ /tilities................................................................... ...................................................... ............................................... .................... 4.1.3 4.1.3 eating eatingu* u* of the Firing Firing ood... ood........ .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .............. ......... 4.1.4 4.1.4 )tarting )tarting the Main -urners.. -urners....... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .................. ......................... .............. 4.1.! 4.1.! eating eating /* and )tarting )tarting the Plant....... Plant............ .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... ............. .......... 4.2 "old )hutdow )hutdown n of the Indurat Induration ion )ystem.... )ystem......... .......... .......... .......... .......... .......... .............. ..................... ........................ .............. 4.3 Interru*tions Interru*tions and Failures.................................... Failures............................................................... ........................................................ ............................. 4.3.1 4.3.1 Interru* Interru*tion tion of the Indurating Indurating Machine.... Machine......... .......... .......... .......... .......... .......... ........... .................. ........................ ............ 4.3.2 4.3.2 Interru* Interru*tion tion +ess Than Than % Minutes. Minutes...... .......... .......... .......... .......... .......... .......... ............. .................... ........................ ............... ... 4.3.3 4.3.3 Interru* Interru*tion tion More Than Than % Minutes Minutes..... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... ............ ................ ......... 4.3.4 4.3.4 Power Power Failure. Failure...... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... ................ ....................... ................... ....... 4.3.! 4.3.! mergen mergency cy Diesel Diesel &enerat &enerator or Failure.. Failure....... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .............. ......... 4.4 Faults Faults during during '*eratio '*eration.... n......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... ............. ................ ........ 4.4.2 4.4.2 4.4.3 4.4.3 4.4.4 4.4.4 4.4.! 4.4.$ 4.4.$ 4.4.% 4.4.% 4.4.7 4.4.7 4.4.8 4.4.8 4.4.15 4.4.11 4.4.11 4.4.12 4.4.13 4.4.14 4.4.1! 4.4.1$ 4.4.1% 4.4.17 4.4.18 4.4.25

-readow -readown n 5f 6iratin 6irating g Feeders Feeders .......... ............... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... ............ ....... -readow -readown n for -elt "on(eyor "on(eyor .......... ............... .......... .......... .......... .......... .......... .......... .......... ........... .................. .................... ........ -readow -readown n of the earth earth +ayer Feeding Feeding )ystem..... )ystem.......... .......... .......... .......... .......... .......... .......... .......... ........ ... -readown -readown of the Tra(elling Tra(elling &rate. ..................................................... .................................................................... ............... -readow -readown n of the &reen &reen Pellet "on(eyo "on(eyorr )ystem...... )ystem........... .......... .......... .......... ........... ................... ............... -readow -readown n of the &reen &reen Pellet /ndersi /ndersi#e #e )ystem..... )ystem.......... .......... .......... ............ .................... .................. ..... -readow -readown n of the Doule Doule Dec ,oller )creen..... )creen.......... .......... .......... .......... .......... .......... ............ ................. .......... -readow -readown n of "ooling "ooling Air Fan..... Fan.......... .......... .......... .......... .......... .......... .......... .......... ............ ................... ........................ ............ -readown -readown of 0indo ,ecu*erating ,ecu*erating Fan. 9This o*tion o*tion should e authori#ed authori#ed y )enior Manager PP:............................................... PP:........................................................................ ......................... .............. ............ .. -readown -readown of /*draft /*draft Drying Drying Fan........................... Fan...................................................... ............................................ ................. -readown -readown of 0indo haust haust Fan............................ Fan.................................................................. ...................................... -readown -readown of ood haust Fan....................................... Fan............................................................. ...................... .......... -readown -readown of -urner -urner cooling cooling 9"ooling: 9"ooling: Air Air Fan................................................. Fan................................................. . /nsatisfactory /nsatisfactory Permeaility Permeaility of Pellet Pellet -ed................ -ed....................................................... ....................................... .... Too Too Much "harge )u**lied )u**lied to Tra(elling Tra(elling &rate............................................ &rate................................................... ....... 0indo Tem* Tem*erature erature Profile Too Too igh...................................................... igh............................................................... ......... Pellet Tem*erature Tem*erature at Tra(elling Tra(elling &rate Discharge To Too igh................................ igh................................ Firing ood Pressure Pressure To Too igh..................................... igh........................................................................... ...................................... -readown -readown of "ooling "ooling 0ater 0ater )ystem )ystem for the Tra(elling Tra(elling &rate.................. ..........

5. Interlocks and Alarms....................... Alarms.................................................. ...................................................... ...................................................... ........................... !.1

Interlocs............................. Interlocs........................................................ ...................................................... ............................................................. .................................. !.1.1 !.1.1 Tra(elli Tra(elling ng &rate.... &rate......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .............. ...................... ............... .. !.1.2 ood ehaust air fan .................................................. ............................................................................. ........................................ ............. !.1.3 !.1.3 /*draft /*draft Drying Drying Fan; Fan; 0indo 0indo ,ecu*e ,ecu*eratio ration n Fan ; 0indo 0indo hau haust st Fan .......... .......... !.1.4 !.1.4 "ooling "ooling Air Air Fan..... Fan.......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... ............... ................... ......... !.1.$ !.1.$ Associate Associated d Ancilla Ancillary ry )ystems )ystems..... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... ............... ...................... ............

6. Alarms................................. Alarms............................................................ ...................................................... ...................................................... .......................................... ............... . Re!uired "o#ic and Instrumentation................ Instrumentation........................................... ............................................................... .................................... %.1 %.2 %.3

-ed +e(el +e(el and &rate &rate )*eed. )*eed...... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... ........... .................. ..................... ......... Pallet "hange Facility...................................... Facility................................................................. ............................................................ ................................. Pallet "ar Identification............. Identification........................................ ...................................................... ...................................................... ............................. ..

1. Intr Introd oduc ucti tion on

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The *ur*ose of the induration section is to dry; heat harden and cool the green *ellets to *roduce a fired *ellet with *ro*erties suitale for *rocessing into s*onge iron in the Direct ,eduction *lant. The *ellets are hardened on a 3meter wide )traight &rate induration machine. The machine has a Parea of 178m 2. &reen *ellets are dried in two stages; u*draft followed y downdraft drying gas flow. The dried *ellets are *reheated to a *rogressi(ely higher tem*erature. The *ellets are then fired at a**ro. 1355 o" to *ro(ide the recrystallisation and slag onding which will gi(e the *ellets ade
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2. Induration Process Review 2.1

The Indurating machine

The *ellet induration machine consists of a continuous strand of cast steel *allets which carry and contain the green *ellets and which con(eys the *ellets in a layer in continuous motion through the machine. The strand com*rises of 157 rail mounted *allet cars and gas sealed at the hood and windo sides. The ottom of the *allet car 9the suction area: consists of narrow s*aced se*arate gratears; which allow *assage of the gaswhile *re(enting the *ellets from falling through. The *allet cars are drawn from the return strand and *ushed along the u**er strand y a toothed s*rocet wheel dri(en y a (ariale s*eed motor at the feed end of the machine. Pallets are lowered from the to* strand to the return strand y a similar nondri(en s*rocet at the discharge end. The e*ansion in the strand; which (aries according to tem*erature of  the com*onents; is *ro(ided y a counter weight tensioning unit which controls the hori#ontal *osition of the lowering wheel. The grate is *ro(ided with a refractorylined hood ao(e the machine and windoes elow the machine. The hood is *ro(ided with watercooled side and trans(erse lintels. )e*aration of the #ones in the hood is *ro(ided y internal di(iding affle walls and in the windoes y mo(ale shellsha*ed dead *lates. Two false windoes are connected to the ehaust gas system to *ro(ide clean and cool conditions at the feed end of the machine. -elow the induration machine is a drile con(eyor which collects s*illage from the tail 9dri(e: *ulley of the machine; *ellets dislocated from the return strand *allets and dust and s*illage from windoes; which *ass through a series of airo*erated doule *endulum (al(es. The s*eed of the strand; tem*eratures; gas (olumes and *ressures can e (aried to otain o*timal *rocess conditions.

2.2

Process Areas and Process Fans

There are % *rocess areas in the indurating machine; di(ided as follow= /*draft Drying area Down Draft Drying area Pre heat area

8 meters; corres*onding towindo 1 to 3. $ meters 8 meters

> >

to > 4 to !. to

> $ to 8.

Page

Firing area

1$ meters

 After Firing area

2 meters

Primary cooling

1$.! meters

)econdary "ooling

4.! meters

>

to

>to

>

>to >

to

>

15 to 13

14. >

1! to 251?2 >

251?2 and 21.

Total *rocess area $3 m. in length @ 3 m. in width. or 178 meters )
"ooling Air Fan 9&!552:

•

/*draft Drying Fan 9&!512:

•

0indo ,ecu*eration Fan 9&!522:

•

0indo haust Fan 9&!532:

•

ood haust Fan 9&!542:

•

In addition; a ood )ealing Air Fan 9&!54! 54$: is *ro(ided.

 All fans are centrifugal design and the flow through them is controlled y 666FD.

2.3

Material fow through the machine

Prior to the green *ellet feed a hearth layer of 15512! mm is laid on the grates of the *ellet cars. At the same time; a !5mm wide side layer is *laced against the inside each of the (ertical sides of the *ellet cars. The hearth layer le(el is controlled y 3 ultrasonic *roes 9&3+111;112;113:. The hearth layer and side layer consist of already fired *ellets to *rotect the grate ars 9or  sides as the case may e: from the high tem*erature of the *rocess gas. The green *ellets are then de*osited on the hearth layer from the roller screen in a layer of a**ro. 455mm. The total ed height 9a**ro. !55mm: is detected y ultrasonic *roes. The s*eed of the grate is (aried automatically from this signal to maintain a constant ed height 9loo* o.$3"1%6: . This ensures that the gas can flow through uniformly at all *oints. The *ellets then undergo the following o*erations= drying; firing and cooling.

2.3.1 &r'in# The first #one is the u*draft drying #oneand co(ers windoes os. 1 to 3. In this #one hot gas 9a**ro.275 °": from the second cooling #one flow from ottom to to* through the *ellet ed. The gas asors the moisture *resent in the *ellets and lea(es the *ellet ed saturated and at a low tem*erature 975 °": and high moisture content.

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The second #one is the downdraft drying #one etending from windo no. 4 to !. ere; gas with 275 to 355B" is used to dry the *ellets from to* to ottom. The remaining moisture in the u**er layer is thus remo(ed. The gases used for downdraft drying come from the induration #one windoes 915 to 13:. After they ha(e *assed through the *ellet ed they contain much moisture and little heatC they are now no longer useful and are discharged (ia a )P to the stac.

2.3.2 Pre(eatin#  After drying; the *ellet tem*erature has to e gradually raised to the re
2.3.3 )irin# In this #one there is a downward gas flow which is raised to a *ea tem*erature of  a**ro. 12$5 to 1315 °" y the urners 9de*ending on  caron addition:. The firing section etends from windo o.15 to 13.As the material flow of *ellets *asses through this #one; the hot gas cause the heat front to descend *rogressi(ely through the *ellet ed. The tem*erature of the gas in the hood and the
2.3.4 A*ter+*irin# 0hen the end of the firing #one has een reached; the a**ro. 12$5 to 1315 °" heat front has still not reached the lowest layer of *ellets; The material now enters the after firing #one; which etends for windoe o. 14:where the gas tem*erature is immediately lowered to a**ro. 12351275 °" without the use of urners. This lower gas tem*erature is oosted sufficiently y the hot to* layer; and thus the (ery lowest layer of  *ellets is rought to the correct induration tem*erature. The ehaust gas from the firing #one and afterfiring #one are *artly discharged to the stac and *artly used again for downdraft drying and *reheating. The ehaust gas of the *reheat #one and the first *arts of the firing #one contain moisture and are low in tem*erature and are thus discharged to the stac.

2.3.5 Coolin# in t(e 1st coolin# ,one If the machine is *ro*erly set u*; the 12$5 to 1315 °" heat front  after lea(ing the after firing #one  will ha(e *assed com*letely through the full green *ellet layer. The 155 to 12! mm thic hearth layer; howe(er; still *rotects the grate ars against the heat front. 0hen all the *ellets ha(e een rought to the correct tem*erature y the heat front; the gas flow is re(ersed and cold air is now lown in to cool the grate ars and the *ellets on them. This *re(ents o(erheating of the grate ars. Tha gases lea(ing the to* of the *ellet ed range from aout 12351275B" to aout $!5%55B" .The first cooling #one etends from windo o. 1! to half of windo o.25 9Partial:.

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2.3.6 Coolin# in t(e 2nd coolin# ,one In the second cooling #one the *ellets are cooled still further.&as heated during the *rocess are used in /*draft drying. The second cooling #one etends from half of  windo25;towindo o. 21.

2.3. -ac(ine &isc(ar#e The lowest layer is taen closeto the amient tem*erature; while the to*most layer is 255 to 355°". As a result the a(erage layer tem*erature ecomes 75  155 °". The hotgas from the second cooling #one hood are used for the /*draftDrying #one. The *ellets; sufficiently cooled to e trans*orted on ruer con(eyor are discharged from the *allets at the ti**ing wheel into a discharge ho**er mounted on load cells. Pellets are fed out of the discharge ho**er at a controlled rate onto two (irating feeders which feeds the *roduct elt &%552A.

2.4

Gas fow through the machine

2.4.1 Overview  All *rocess gas 9essentially air: used in the machine is deri(ed from the "ooling Air Fan 9&!.552: and y inleaage of amient air into the sides and ends of the induration machine. The cooling air fan 9&!552: draws in amient air and forces it u* through the cooling #ones at a *ressure of u* to!55 mm 0".The air flows through the *ellet ed and cools the fired *ellets. The air; which is now hot; enters the hood of the 1st and 2nd cooling #ones. The *rocess gas deri(ed from the cooling #ones can e considered as two se*arate streams designated as *rimary and secondary *rocess gas streams.

2.4.2 Primar' Process $as tream The larger *art of the cold air which *asses through the hot *ellet layer has; after cooling these *ellets reach an a(erage tem*erature of aout 7558!5G" 9in 1st cooling #one: and is con(eyed into the *reheat and firing #one (ia the direct recu*eration header and through downcomers to the urner chamers arranged on each side of the grate. . In the hood of the firing #one; F?' urners heat u* the gas from 7558!5G" to a *ea tem*erature of a**ro. 1315G". The tem*erature to which the gases is raised in each section of the firing #one is set y the "ontrol ,oom '*erator de*ending on the raw material conditions and the
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2.4.3 econdar' Process $as tream Part of the cooling air is drawn from ao(e the second cooling #one y the /*draft Drying Fan 9&!.512: is fed to the u*draft drying #one at a**roimately 275355 '".. This air is discharged to atmos*here; after *assing through the ed; y the ood haust Fan 9&!.542:.

2.4.4 Ot(er )eatures o* t(e Process $as 'stem The *rimary and secondary *rocess gas streams are interconnected at two *oints= • Interconnecting ducts from the discharge of the 0indo ,ecu*eration Fan to the inlet of the /*draft Drying Fan 9&!.512: through dam*ers &!.1529&!.52!: • -leed off from 0indo ,ecu*eration Fan to the /*draft Drying hood through dam*er  &!.115 -ecause there is an o(er*ressure in the entire 1st cooling #one; the seal etween the hood of this #one and the *ellet cars is *ro(ided y sealing air su**lied y the hood seal fan 9&!54!::.

3. Control Review 3.1

Oerating Modes

3.1.1 "ocal -ode T)TH mode.

3.1.2 Remote -ode 
3.1.3 -anual -ode The out*ut of an instrumentation loo* controller is directly set y the "ontrol ,oom '*erator  from the "entral "ontrol ,oom 0orstation; irres*ecti(e of the relati(e (alues of the *rocess (ariale and the set*oint.

3.1.4 Automatic -ode  The out*ut of an instrumentation loo* controller is directly set y the D") de*ending on the relati(e (alues of the *rocess (ariale and the set*oint.

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3.1.5 Cascade -ode // a: The set*oint of an instrumentation loo* controller 9sla(e: is set y the out*ut from another 9master: instrument. : 0hen the *ert )ystem is im*lemented; this will e the nominated mode when instructions and set*oints are determined y the *ert )ystem and acted on y the D").

3.2 Princial !ontrol Mechanisms in the Induration machine "ontrol of the *rocess is achie(ed y (arying the tem*erature and flows of *rocess gas through the machine. )ome o*erating *arameters; such as ed height; ood tem*erature Profile in thePreheat and Firing ones and -urnthrough are adEusted y the "ontrol ,oom '*erator according to the *roduction schedule and the
3.2.1 $rate peed and 0ed &ept( The grate is a (olumetric con(eying de(ice and at a constant total ed height; the s*eed of  the tra(elling grate is directly related to the
3.2.2 ood emperature Pro*ile The *rinci*al *rocess control is the attainment of the correct tem*erature *rofile of the gas entering the ed from the hood in the *reheating and firing #ones. The urners are di(ided into ten control grou*s along the length of the machine in the *reheat and firing #ones. The first two of the down comersactually contain no urners.. The tem*erature for each #one is set manually y the "ontrol ,oom '*erator. De(iation from the set*oint for a urner *air  causes the s*iderH are indicating the tem*erature detected ao(e the ed in the *reheat #one. The P 1 and P 2 tem*erature are set to control the Page

(al(es &4.533 K 534. For wet feed and?or high tonnages these should e set as low as *ossile to a(oid s*alling. First 2Down comers o urners Ty*ical hood *rofiles are indicated in the tale elow= 'pical et Point o coke

'pical etpoint wit( 1.4 coke

o urner one

4!5B"

42!B" or less

-urner one 1?1

$!5B"

$2!B" or less

-urner one 2?2

7!!B"

755B"

-urner one 3?3

1555B"

855B"

-urner one 4?4

11!5B"

15!5B"

-urner one !?!

12!5B"

11!5B"

-urner one $?$

1315B"

1255B"

-urner one %?%

1315B"

12!5B"

-urner one 7?7

1315B"

12%!B"

-urner one 8?8

1315B"

12%!B"

0urner o. pairs

-urner one 15?15

1315B"

12%!B"

-urner one 11?11

1275B"

1235B"

3.2.3 0urn+t(rou#( Control 3.2.4 The most im*ortant controls in the machine is >urnthroughH. This determines the *oint at which the heat front reaches the ottom of the ed and the intensity of this heat front and has a direct influence on *ellet
3.3

"econdar# machine

!ontrol

Mechanisms

in

the

Induration

These controls are used to alance the *rocess gas flow through the machine and maintain the re
outlined ao(e. 'nce estalished the set*oints of these loo*s are rarely changed y the o*erator during normal o*eration.

3.3.1 Coolin# Air )low The flow through "ooling Air Fan &!552 is controlled y maintaining a slightly negati(e *ressure of 3  !mm 0& in the firing #one hood 9loo* no. &4P35!:. If the 0indo ,ecu*eration Fan 666FD "'T,'++D 9*ossily due to low urnthrough tem*erature:; the ao(eed *ressure will ecome more negati(e and "ooling Air flow will increase 9y 666FD: until the set*oint is restored.

3.3.2 7pdra*t &r'in# 8ind9o/ Pressure The s*eed of the /*draft Drying Fan &!512 is controlled to maintain a set *ressure of  a**roimately 2!mm 0"in the hood ao(e the second cooling #one 9loo* no. &4P35$:. If the windo *ressure in the /*draft Drying #one eceeds a maimum set*oint of !55mm 0"; *rocess gas is directed around the ed y a y*ass duct containing dam*er &!51! 9loo* no.&!15$to the inlet of the )P1552; rather than through the ed.

3.3.3 7pdra*t &r'in# emperature 1. If /*draft Drying tem*erature is too high; it can e tem*ered y air drawn in from atmos*here into the duct from 2nd cooling #one through leedin dam*er &!51$ 9loo* &4T353:. This is (ery unliely as the grate asors %5 of the heat and the ottom of the ed sees lower tem*eratures. 2. If the /DD tem*erature is too low; at start u* for instance; it can e oosted y leeding *rocess gas from the outlet of the 0indo ,ecu*eration Fan &!522 to the suction side of  the /*draft Drying Fan y dam*er &!52! and +oo* o. &!T12!.

3.3.4 &owndra*t &r'in# emperature If the tem*erature of the *rocess gas for Downdraft Drying is too high9maimum 325B":it can e controlled at the inlet duct of the 0indo ,ecu*eration Fan y leedingin cold air from atmos*here through Tem*ering Air Dam*ers &!521 9loo* &!T124:.

3.3.5 8ind9o/ :/(aust )an )low Flow through the 0indo haust Fan; which draws *rocess gas from windo os. 4 to8 and includes downdraft drying; *reheating and the first *art of the firing #ones; is controlled y the tem*erature of windoes os.% or 7; as selected y the o*erator 9loo* no &!T11%:.

3.3.6 &owndra*t &r'in# ood Pressure This *ressure; ty*ically 1!mm 0&; is set y the o*erator9loo* no.&!P11!: and is controlled y dam*er &!P115. •

&!115 -leed off from Downdraft Drying ood to /*draft Drying ood controlled y P?T &!P 11!.

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3.3. 7pdra*t &r'in# ood Pressure Ty*ically 2!mm 0&; this *ressure is set y the o*erator and controls the s*eed of the ood haust Fan &!542 through loo* no. &!P114.

4. Operational Review 4.1 "tarting $ the Plant a%ter a Planned "hutdown 4.1.1 Routine C(ecks 1: 'nce the o*eration de*artment; *rocess de*artment; electrical de*artment; re*airs and maintenance de*artment; instrumentation and control de*artment; utilities de*artment 9water?com*ressed air?instrument air?fuel oil: ha(e gi(en clearance for the *lant to start o*erating; it can e started u* from the control room. 2: All elt con(eyors and material transfer *oints must e checed to mae sure they are free from foreign matter. 3: All interloc e
4.1.2 7tilities 1: A chec must e made that the cooling water circulation system is o*erating and that sufficient cooling water is a(ailale to the indi(idual users. 2: The following users must e checed= 

"ooling water system for the lintels of the tra(elling grate.



"oolingwater for the shuttle elt con(eyor hydraulic system.



"ooling water for the hydraulic system of the mier.

3: The tra(elling grate o*erator must chec the lintels water discharge *oints to ensure that the correct water flow rates are set to water com*artments 9lintels: along the tra(elling grate and cross eams 9lintels: etween the indi(idual #ones. 4:

+P& must e a(ailale at the correct *ressure; tem*erature and su**ly rate to start u* the *lant.

!: "om*ressed air must e a(ailale in sufficient
Doule fla*s (al(es under the windoes.



,A6L) under the )P. 1.551;552



Ploughs on con(eyor &1.51$ to feed mied ins.



+uricating systems for the alling disc.



+uricating system for the tra(elling grate;air su**ly to indurating machine urners. Page

$: The entire length of the tra(elling grate must e filled u* to a de*th of 3!5 mm with hearth?side layer. The hearth layer in should e full. %: Instrument air must e a(ailale at a *ressure of ! ar. 7:

Process fans= a:

)tart hood ehaust fan &!.542 to *ro(ide a slight negati(e *ressure in the furnace hood

:

)tart one of the -urner Atomi#ing air fans .? &4.542 from the control room.

c:

)tart /DD *rocess fan &!512

d:

The motor s*eed of the *rocess fans are adEusted such that a slight negati(e *ressure de(elo*s in the firing hood.

4.1.3 eatin#+up o* t(e )irin# ood In the tem*erature range elow a**ro. %55 '"; the firing hood is heated u* with the tem*erature controllers in manual mode. In this case; it is essential that the o*erating staff  *ay s*ecial attention to monitoring the indi(idual urners. 0hen the tem*erature in the firing hood reaches aout %55 '"; the tem*erature controllers can now e switched o(er to automatic mode. From amient tem*erature to %55 '"; *ilot urner are re
4.1.4 tartin# t(e -ain 0urners see 9loom///// Pro(ided that all conditions for starting are fulfilled and that natural gas is on line u* to the safety shutoff (al(e; the indi(idual urners can e started once the following conditions are fulfilled= 1:

That one of the cooling water *um*s is in o*eration. &$.514 ', &$.51!

2:

The hood ehaust fan &!.542must e in o*eration.

3:

The u*draft drying fan&!.512must e in o*eration. 9'*tional; not re
elow 2!5 ":. 4:

o emergency switch may e actuated.

!:

'ne of the -urner cooling air fans &4.541or&4.542must e in o*eration.

$:

-urner cooling air must e a(ailale at the correct *ressure.

%:

The +P& gas tem*erature and *ressure may e correctly adEusted.

7:

The instrument air *ressure must e a(ailale.

8:

'nce these conditions are fulfilled; the urners can e started.

Page

4.1.5 eatin# 7p and tartin# t(e Plant  After a *lanned shutdown where some refractory re*airs?installation had een done; the firing hood should e heated u* from amient to 755B" at a rate of 45B"?h. From 755B" on; a rate of %5 B"?h is used. eating u* too fast; with an ecessi(e numer of urners and with long flames must e a(oided to *rotect the refractory lining from thermal shocs 9which shorten its ser(ice life:. During heating u*; the tra(elling grate must e co(ered with a fired *ellet; hearth?side wall *rotection layer of 3!5 mm minimum.  As already descried; the hood ehaust fan and the u*draft drying fan are o*erating. 'ne -urner atomi#ing air fan is also in o*eration. -leedout dam*er &!51! is closed. 1: The first *ilot gas urners are ignitedC two urners on either side are normally sufficient. 2: /ntil tem*erature reaches at around 3!5 to 455 B"; no further urners are re
a9le 1 ;one

Pressure

/*draft drying hood

2! mm 0"

Downdraft drying hood

1! mm 0"

Preheating #one

3 ? ! mm 0"

and

)econd cooling #one

firing

1! mm 0"

Those *ressure adEustments are *ossile y modulating the motor s*eed on  fan &!.542 and /DD fan&!.512. '(er*ressure dam*er &!P114;&4.35$. 12: 0hen tem*erature reaches a**ro. 8!5B" to 1555B"; nearly all urners should e ignited. Page

13: The o*erating staff should tae care of the following rules= ,educing the *rocess gas flow rate raises the tem*erature in firing and cooling #ones. Increasing the *rocess gas flow rate lowers the tem*erature in the firing and cooling #ones. F fan &!.542; ehaust tem*erature should e followed closely; if tem*erature rise ao(e 255B"; F fan &!.542; inlet dam*er will close automatically. 14: 0- &!.532; 0-, &!.522 and "AF&!.552 Fans are now started. 1!: 'nce enough air is eing circulated through the direct recu*eration line 9indicated y *ressure in cooling #one I: the urner control system can e switched from manual to automatic mode. This means that all interloc conditions in the urner safety system now a**ly. 1$: 0hen the tem*erature reaches a**ro. 1255 B" or when the tem*eratures in the windoes rise ao(e the intended o*erating le(els; the de*th of the hearth layer is reduced to 12! mm; and *ossily three alling disc 9roughly 255 t?h: are started. The de*th of *ellets of !55 mm is regulated y means of (arying the s*eed of the tra(elling grate. 1%: 'nce the green *ellets ha(e reached the u*draft drying #one; all the firing #ones tem*eratures must e adEusted to their normal o*eration tem*erature. ood *ressure in u*draft drying #one must e set to  3 mm 0" PI" &!P.114 17: 'nce the green *ellets ha(e reached windo3; the control (anes of the 0- fan &!&113 is o*ened a**ro. 2!. 18: 'nce the green *ellets reach windo$; the )PDon the 0-, fan &!.522 also is increase y a**ro. 2!  35.The tem*erature in firing #one should reach normal ; 12!5 to 1355B" at the *ea. 25: 'nce the green *ellets ha(e reached cooling #one I; a chec must e made of whether the windo tem*erature *rofile has settled down right. The tem*erature in windo14 should now e a**ro. 3$5 to 3%5 B". 9assuming no coe addition: 21: If the tem*erature there is lower; the gas flow rate of 0- &!.532 and 0-, &!.522 fans must e increasedC if the tem*erature is higher; the gas flow rate of oth fans must e reduced; y adEusting fan motor s*eed accordingly. 22: A**ro. 1 hour later; when the correct windo tem*erature ha(e de(elo*ed; the discharge material from an another alling disc is di(erted to the tra(elling grate. 23: As already descried; once green *ellets are reaching the (arious #ones; the gas flow rate of fans 0- &!.532 and 0-, &!522 must e adEusted; so that the correct windo tem*erature *rofile is maintained. 24: The cooling airflow rate of "AF &!.552 is adEusted automatically; y means of controller P", &4P35!. so that a negati(e *ressure of a**ro. 3 mm 0& de(elo*s in the firing #one. 2!: The /DD Fan &!.512 must e set; so that a negati(e *ressure of a**ro. 3 mm 0" de(elo*s in cooling #one II 9PI" &!P35$:. 2$: This *rocedure is now re*eated; until 9*ossily: 3 alling discs are feeding to the tra(elling grate with an inlet feed of 1$5 T?. 2%: 'nce the tra(elling grate has een o*erating at design ca*acity for a**ro. 1  2 hours; all *rocess conditions must ha(e settled down correctly. All control )ystems now get switched o(er to automatic control from D " ) . 27: It must e rememered that as the green *ellet (olume increases ste* y ste*; the tra(elling grate s*eed is increased; which can lead to the *ellet tem*erature at the tra(elling grate discharge rising for a short time. If the *ellet tem*erature is too high; the water s*rinling system 9&%T.151 at *roduct elt con(eyor &%.552 or Page

&%.552A is started? o*ened automatically. 28: As the green *ellet (olume increases. To *rotect the green *ellets in the heating and firing #one; it is ad(isale to adEust *ressure in windoes $ to 14. 0hen the *lant is o*erating at design ca*acity; the following *ressure *rofile should e estalished= 0indo o.$ to 7 &!T15! to 15%.  455 mm 0& 0indo o. 15 to 14 &!T158 to 113.  455 mm 0& 35: A**roimate set *oints for the *rocess fans and motor s*eed; with the *lant o*erating at design ca*acity=

a9le 2 Item

Instrument

et point

"A Fan &!552

&4P35!

 3 mm 0&

 Fan &!542

&!P114

 2! mm 0&

0-, Fan &!522

&!T11!

355B "

0- Fan &!532

&!T11%

175 deg "

/DD Fan &!512

&4P35$

 1!mm 0&

4.2 !old "hutdown o% the Induration "#stem The descri*tion assumes that= a: The *lant is o*erating normally : All control systems are in automatic control. D " ) c: Ins*ection or re*air wor on the refractory lining maes it necessary to cool the hoods down. 1: The de*th of the hearth layer is increased to 3!5 mm. The su**ly of green *ellets is cut off. The tra(elling grate s*eed control system is switched o(er from automatic to manual control. 2: The green *ellet con(eying system to the tra(elling grate is em*tiedC it can then e sto**ed. ote=During shutdowns; the mied material ins ao(e the alling discs should not stay filled otherwise ridges of material will form around the in outlets. It is therefore ad(isale to em*ty the ins or; at the (ery least; to ee* the in le(el elow 25. If the ins at the weighting elt scales are re
one no urner

4!5B"

-urner one 1?1 -urner one 2?2 -urner one 3?3 -urner one 4?4 -urner one !?! -urner one $?$ -urner one %?% -urner one 7?7 -urner one 8?8 -urner one 15?15 -urner one 11?11

$!5B" 7!!B" 1555B" 11!5B" 12!5B" 1315B" 1315B" 1315B" 1315B" 1315B" 1275B"

7

A negati(e *ressure of  3 mm 0& is e*t in the u*draft drying #one.

8:

The tem*eratures in windoes 15 to 14 are controlled y the motor s*eed of fan 0-, &!522. The dam*er &!521 gets o*ened to 155 if re
15:

0hen full hearth layer reach end of windo14. All urners are sto**edC 0-, &!522; 0- &!532 and "A &!552 Fans are sto**ed. -urner cooling air must e a(ailale to cool the urners.  All urners are remo(ed for general ins*ection and maintenance.

11:

6ent door are o*ened on suction duct of fans 0- &!532 and 0-, &!522. Thus it is not asolutely re
12:

All dam*ers are *ut in manual mode and closed and fan s*eed on  &!.542 and /DD &!.512 fans and dam*er &!&.114. Dam*er &!&111 is e*t at 155  o*en in manual mode. 'nly motor s*eed is adEusted accordingly.

13:

Tem*erature of  fan&!.542 should e followed closely; if tem*erature eceeds 255'"; inlet dam*er will close automatically.

14:

Machine should e cooled down at a rate of %5 '"?hr. y adEusting oth fan motor  s*eed.

1!:

'nce the hood tem*erature has dro**ed elow 2!5 B"= Page

a: In the case of maEor re*airs to the refractory lining; the gate (al(es for hearth?side layer get closed and the tra(elling grate gets em*tied. The hearth layer in is filled u* y means of the hearth layer con(eying system. As soon as the tra(elling grate is em*ty; the grate and the con(eyor systems are sto**ed. The greasing system for the tra(elling grate is sto**ed. : In the case of ins*ections and minor re*airs to the refractory lining; the tra(elling grate is sto**ed. 'nce the con(eyor systems eyond are em*ty; they are sto**ed. c: The greasing system for the tra(elling grate gets switched off. 1$:

At this *oint; if faster cooling is re
1%:

The dust collection systems for the *lant are switched off.

17:

Assoon as the refractory lining has cooled down far enough 9elow !5 B":C the remaining fans can e sto**ed. 0hen 0- fan &!532 the auiliary oil *um*s is starting automatically. After a *reset time; that *um*s automatically sto*. The dam*er of  fan &!542 to e o*ened; so that the flue effect causes a slight draft.

18:

4.3

The cooling water system for the tra(elling grate should stay in o*eration; until the ins*ection of the hoods 9lintels and cross lintels: has een done.

Interrutions and Failures

4.3.1 Interruption o* t(e Induratin# -ac(ine The firing hood tem*erature to e set u* for an interru*tion mainly de*ends on the following conditions= a: The length of the interru*tion : The reason for the interru*tion It is *erfectly *ossile to maintain the firing hood tem*erature at 855B" for few hours; *ro(ided that the tra(elling grate can e o*erated should the tem*erature raise for some reason. owe(er; it is not ad(isale to ee* the tem*erature ao(e 855B"; if the indurating machine will not start soon. In this case; either the tra(elling grate must e ca*ale of mo(ing again after a few hours or the tem*erature in the firing hood must e lowered further.

4.3.2 Interruption "ess (an  -inutes  A sto**age of the tra(elling grate is one of the most dangerous emergencies that can occur. The control room staff must tae action at once. 1: The urners are switched to +ow fire. Automatically until they reach the hold tem*erature the F?' flows to each urner grou* is reduced to minimum. 2: All fan motor s*eed and controllers are e*t in automatic mode. If the control system of 0- &!.532 and 0-, &!.522 fans were switched o(er to manual control. It is not ad(isale to o*erate the indurating machine in manual mode for long *eriod of time; sinceC during sto**age this can *roduce (ery ha#ardous and dangerous conditions. 9'(erheating of *allet car; fan; etc.:. 3: -leedin dam*er on 0- &!.532 and 0-, &!.522 fans are o*ened at 155. Page

4: 0ith the fans and urners in o*eration; the firing hood tem*erature should stay same while running. If hood tem*erature rises ecessi(ely; urner should e tri**ed. If  windoes tem*eratures rise ecessi(ely; 0- &!532 and 0-, &!522 fans s*eed should e reduce. !: As soon indurating machine can e started again; green *ellet feed system should e *ut in o*eration and all other o*erating conditions resume on the indurating machine. $: If tra(elling grate is sto**ed for more than % minutes 0- &!.532; 0-, &!.522 and *ut on turning gear 9automatically:"AF &!.552fans must e sto**ed.

4.3.3 Interruption -ore (an  -inutes 1: If tra(elling grate is sto**ed for more than % minutes 0- &!.532; 0-, &!522 and "AF &!552fans must sto*. -urner cooling air must e a(ailale to cool the urners. 2: All the urners are *ut on hold condition; 855B".9low fire followed y tem*erature hold:. 3:All motor s*eed control are *ut in manual mode ece*t &!.542; /DD &!.512 and leedin dam*ers &!.518 and &!.51$. 4: -leedin dam*er are o*ened on suction duct of fan 0-, &!.522. This it is not asolutely re
4.3.4 Power )ailure If the *ower su**ly fails; the entire *lant o*eration is interru*ted and all motor dri(es are sto**ed. To a(oid damage to the mechanical e
a: If the *ower failure is the result of a short (oltage fluctuation; the *lant can e started u* again as soon as the main *ower su**ly functions again. : If a com*lete readown o(er a considerale *eriod occurs; the a**ro*riate dri(es are started automatically or local. c: Following dri(es are to e started immediately as soon emergency *ower is made a(ailale.

&escription "ooling 0ater Pum*s 9automatically after 15 sec.:

Item &$.514 Page

"ooling 0ater after 15 sec.: -urner cooling after 15 sec.:  Air "om*ressor sec.:  Air "om*ressor sec.:

Pum*s 9automatically Air Fan 9automatically 9automatically after 15 9automatically after 25

&$.557 &4.541?.542 &$.525 &$.52!

d: Doors are manually o*ened on windoes4to14. e: nsure that firewater 91 of 2: is running. f:

All indurating machine urners should e *urged and remo(ed.

4.3.5 :mer#enc' &iesel $enerator )ailure If the *ower su**ly fails; the entire *lant o*eration is interru*ted and all motor dri(es are sto**ed. To a(oid damage to the mechanical e
4.4

Faults during Oeration.

The following directi(es a**ly to faults in the o*eration of *lant e
4: -readown of the tra(elling grate. &3.55% !: -readown of the green *ellet con(eyor systemO&2.5!5 $: -readown of the green *ellet undersi#e?o(ersi#e system &3.15!?&3.554 %: -readown of doule dec roller screen. &3.553?M51;M52 7: -readown of the cooling air fan.&!.552 8: -readown of the windo recu*erating. &!.522 15: -readown of the u*draft drying fan. &!.512 11: -readown of the windo ehaust fan. &!.532 12: -readown of the hood ehaust fan. &!.542 13: -readown of the -urner "ooling air fans &4.541?542 14: /nsatisfactory *ermeaility of *ellet charge 1!: Too much charge su**lied to tra(elling grate 1$: 0indo tem*erature *rofile too high 1%: Pellet tem*erature at tra(elling grate discharge too high 17: Pressure in firing hood too high 18: -readown of the lintel cooling water system for the tra(elling grate

4.4.1 0reakdown o*
4.4.2 0reakdown *or 0elt Conve'or $.%%1 If elt con(eyor &%.551 reas down.Production can continue; since (irating.feeder&%.553; &%.554 and elt con(eyor &%.552Ais in o*eration. The fault should e found as soon as *ossile; ecause dust and s*illage will collect in the ho**ers ao(e the doule *endulum (al(es; could result in an o(erload when restarting the elt con(eyors; &%.551 and &%.552A. The tail end of "on(eyor &%.551 will ha(e to e ins*ected efore any attem*t to restart it. During sto**age; *ellets from indurating machine dri(e station will get accumulated on the con(eyor tail end.

4.4.3 0reakdown o* t(e eart( "a'er )eedin# 'stem If this con(eying system reas down; no hearth?side layer gets recirculated. If the sto**age only lasts a few minutes 9e.g. if the tri* cord at elt con(eyor &7553 gets *ulled:; there is no *rolem; as in &755! is normally e*t at 75 to 7!  in le(el; which means enough heath?side layer is a(ailale for a**ro. 1! minutes. If it is e*ected to last more than 25 minutes; it is etter to go for an emergency shutdown.

4.4.4 0reakdown o* t(e ravellin# $rate.$3.%% Proceed with shutdown according to )ection 4.3.1 or 4.3.2

4.4.5 0reakdown o* t(e $reen Pellet Conve'or 'stem $2.%5% Proceed with shutdown according to )ection 4.3.1 or 4.3.2

4.4.6 0reakdown o* t(e $reen Pellet 7ndersi,e>Oversi,e 'stem $3.1%5 Proceed with shutdown according to )ection 4.3.1 or 4.3.2

4.4. 0reakdown o* t(e &ou9le &eck Roller creen. $3.%%3 Proceed with shutdown according to )ection 4.3.1 or 4.3.2

Page

4.4.= 0reakdown o* Coolin# Air )an.$5.%%2 If the cooling air fan reas down; the tra(elling grate must e sto**ed immediatel'C otherwise ecessi(ely hot *ellets will e discharged. If the fan can e restarted immediately; urners should e switched on low fire; otherwise if the fan is not started immediately; the urners must e etinguished and the *rocess fans switched off. A su**ly of air must e a(ailale to cool the urners. The (ent door must e o*ened on fan 0-&!.532 and 0-, &!.522. This is not strictly necessary; the doors of windoes $ to 14 can alsoe o*ened to cool the grate to a(oid sagging of *allet car.

4.4.? 0reakdown o* 8ind9o/ Recuperatin# )an $5.%22. Indurating machine is sto**ed. Proceed with shutdown according to section 4.3.1. or 4.3.2. 4.4.1%.0reakdown o* 7pdra*t &r'in# )an $5%12. Indurating machine is sto**ed. Proceed with shutdown according to section 4.3.1.or 4.3.2.

4.4.11.0reakdown o* 8ind9o/ :/(aust )an $5%32 Indurating machine is sto**ed. Proceed with shutdown according to )ection 4.3.1 or 4.3.2

4.4.12.0reakdown o* ood :/(aust )an $5%42 Indurating machine is sto**ed. Proceed with shutdown according to section 4.3..1. or 4.3.2.

4.4.1% 0reakdown o* 0urner Coolin# Air )an $1.%41@ $1.%42 'ne of the two fans is always running; one fan is a standy. If one of the fans in o*eration reas down; the shutoff dam*er closes and the standy fan automatically starts. The shutoff  dam*er o*ens automatically. During the same *eriod the urners will go off due to lac of  atomi#ing air and the grate will sto*; *urging will tae *lace automatically and the urner will e relit. 'nce the tem*erature is ac to normal the grate can e restarted.

4.4.11 7nsatis*actor' Permea9ilit' o* Pellet 0ed /nsatisfactory *ermeaility is usually caused y inferior green *ellets
/nsatisfactory *ermeaility can also e caused y= a: :/cessivel' (i#( *irin# temperatures C This may e the result of incorrect tem*erature set *oints or of faulty tem*erature indication. : Pellets 9urstin# in t(e dr'in# ,ones or pre(eatin# ,one C This can occur; if the moisture is too high or the (olume of green *ellets is too large and the ca*acity of the drying and *reheating #ones is therefore inade
This can occur; if the ultrasonic ed le(el detector is not woring *ro*erly at the machine feed end or if the tra(elling grate s*eed is controlled (ia (olumetric mode and?or manual mode.

4.4.12 :/cessive suppl' o* #reen 9alls to ravellin# $rate If the
4.4.13 8ind9o/ emperature Pro*ile oo i#( This indicates that the su**ly of green *ellets to the tra(elling grate can e increased or the gas flow rates at 0- &!.532 and 0-, &!.522 fans reduced. 1: The instrumentation circuits should e checed. 2: The s*eed control instruments of 0- &!.532 and 0-, &!.522 fans should also e checed.

4.4.14 Pellet emperature at ravellin# $rate &isc(ar#e oo i#( -elt con(eyors &%.552; &%.552A; &7.552; &7.553; &7.554 ha(e to e *rotected y acti(ating the s*rinling water system. Possile causes= 1: &ood antici*ation from control room o*erator while *laying with *rocess *arameters will a(oid any ind of hot discharge. 2: The *ermeaility of the *ellets is unsatisfactory; and action taen to correct this 9as descried ao(e: has no effect or was started too late. 3: The u**er layer of *ellets has urst or een crushed. i tem*erature in Ped le(el too high. 4: The cooling airflow rate is too low as a result of faults in the instrumentation or the dam*er? motor s*eed adEustment system on the cooling air fan; not functioning *ro*erly. !: Too high rate of green *ellets feed to the indurating machine; when dam*ers on fans 0- &!.532 and 0-, &!.522 are already adEusted at the maimum efficiency le(el for those fans cur(es. 9Machine o*erated ao(e actual *rocess *ossile ca*aility:.

4.4.15 )irin# ood Pressure oo i#( If the firing hood *ressure is too high 9*ositi(e:; hot gases are forced through the hood seal; and thus structural *arts get o(erheated. "AF &!552 will sto*. Possile causes= 1: The set *oint for the firing hood *ressure is not set correctly.&4P351;35!;&4354. 2: The s*eed control instruments on the cooling air fan &!552 is defecti(e. 3: There is a fault in the instrumentation system.

4.4.16 0reakdown o* Coolin# 8ater 'stem *or t(e ravellin# $rate If the cooling water system for the tra(elling grate reas down; the a**ro*riate nonreturn (al(e for the emergency water su**ly will o*en automatically. Mae sure that there is really emergency water su**ly. If neither water system is a(ailale; this constitutes anmaEor  Page

emergency. The tra(elling grate must e sto**ed and the hood tem*eratures lowered; meanwhile; the *ressure in the firing hood must e negati(e. The water systems must e in(estigated?corrected immediately 9flow rate; tem*erature; etc.:

5. Interlocks and Alarms &.1

Interloc's

0ith some ece*tions there are few interlocs etween e
5.1.1 ravellin# $rate The tra(elling grate can e started and controlled either from the local *anel or from the central control room. A selector feedac from the field +")to control room determines the *osition of start?sto* control for this e
&rate )*eed and -ed De*th If green *ellet *roduction 9after screening: increases; the grate s*eed increases to maintain a *reset ed height as detected y the ultrasonic *roes at the feed of the machine9&3+151;&3+152;&3+153: 9loo* o.&3+15$:. The con(erse is true. The normal set*oint for ed height will e !55mm The normal grate s*eed is 1.! m?min or lower. If  *roduction rate rises to such an etent that a grate s*eed reaches 1.$! m?s

Page

&.1.2.(ood e)haust %anG&.*42 The hood ehaust fan can only e started if the following conditions are fulfilled= 1. The inlet dam*ers lou(ers are closed 2. The tem*erature of the fan earings is elow*ermissile le(el. $5B" 3. The tem*erature of motor earing is elow *ermissile le(el. $5B" 4. The motor winding tem*erature is elow*ermissile le(el. %5B" !. o emergency utton are actuated.

During normal o*eration the fan sto*s automatically when= 1.

The tem*erature of the fan earings rises ao(e *ermissile le(el $5B". 2.

The (iration le(el eceeds the *ermissile le(el. 135m.

During normal o*eration • • •

F control 9&!542:; is controlled y the hood suction 9&!P114: at !mm to 2!mm. Inlet dam*er9&!&115: is at 155 o*en and the 96FD: controls motor s*eed. If F 9&!542: fan tem*erature reaches at maimum o*erating tem*erature 9175B": inlet dam*er9&!&115: will close to *rotect the fan.

 At machine emergency sto*; the inlet dam*er closes and the 6FD goes to minimum s*eed.

5.1.3.7pdra*t &r'in# )an $5.%12@ 8ind9o/ Recuperation )an $5.%22@ 8ind9o/ :/(aust )an $5.%32@ The interlocs are identical for these three fans. For themto start; the following conditions must efulfilled= 1. The tem*eratures of the fan earings must not e ao(e *ermissile le(el $5B" 2. The control dam*ermust e closed 3. The tem*erature of the motor winding must e ao(ethe maimum *ermissile le(el 4. The tem*erature of the motor earings must e ao(e themaimum *ermissile le(el

0indo haust Fan = 0indo ,ecu*eration Fan=

75m alarm; 135m shutdown 75m alarm; 135; m shutdown

/*draft Drying Fan=

75m alarm; 135m shutdown Page

During normal o*eration the fan sto*s automatically when= 1. The tem*erature of the fan earings rises ao(e *ermissile le(el $5B". 2. The (iration le(el eceeds the *ermissile le(el. 135m. During normal o*eration 1. /DDF control 9&!512: ; • "ontrolled y the /DD *ressure 9&4P35$: at 1!mm0". • Inlet dam*er9&!&111: is at 155 o*en and the 96FD: controls motor s*eed. • If

/DD fan 9&!512: tem*erature reaches maimum o*erating tem*erature9455B": the inlet dam*er9&!&111: will close to *rotect the fan.

 At machine emergency sto*; the inlet dam*er9&!&111: closes; the leedin dam*er  9&!.51$: o*ens 155 and the 6FD goes to minimum s*eed. If /DD fan 9&!512: main motor sto*s auiliary dri(e9&!512M5$: will start to ee* it running at minimum s*eed. 2. 0-F control 9&!532:; • "ontrolled y an a(erage tem*erature set *oint of 175 '" in 0ind o o. %; 7 9&!T11%:. • Inlet dam*er9&!&113: is at 155 o*en and the 96FD: controls motor s*eed. •  A )tand y signal for 0-F controls 9&!532: and?or shutoff dam*er 9&!&113:;  An o*tional method of control is a ,atio "ontrol of a(erage *ressure in wind o !; $; %; 7 9&!P154; &!P15!; &!P15$; &!P15%:and in wind o 15; 11; 12; 13; 14 9&!P158; &!P11%; &!P117; &!P118:. This o*tion can e used ut it is not

recommended y the *rocess designer. •

If 0- fan9&!532: tem*erature reaches maimum o*erating tem*erature 9275B": the inlet dam*er9&!&113: will close to *rotect the fan.

 At machine emergency sto*; the inlet dam*er9&!&113: closes and the 6FD goes to minimum s*eed.

3. 0-,F control 9&!522:; "ontrolled y an a(erage tem*erature a(erage 0ind o o. 12 2 t?c; 13 1 t?c • 9&!T11!:. If this a(erage tem*erature falls elow set*oint; the motor s*eed of fan &!522 increased until set *oint is restored. The normal set *oint for urnthrough is a**roimately 455 '" without caron addition and 3%5 '" with caron addition at a rate of aout 1.4 . Inlet dam*er9&!&112:is at 155 o*en and the 6FD controls motor s*eed. • • If 0-, fan 9&!522: tem*erature reaches maimum o*erating tem*erature9455B": the inlet dam*er9&!&112: will close to *rotect the fan. The leedin dam*er o*ens Q 55.

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 At machine emergency sto*; the inletdam*er9&!&112: closes and the 6FD goes to minimum s*eed.  At that *oint the leed in dam*er will o*en at 155. If 0-, fan 9&!522: main motor sto*s auiliary dri(e9&!522M5$: will start to ee* it running at minimum s*eed

5.1.4.Coolin#Air )an $5.%%2 The cooling air Fan can only e started when the followingconditions are fulfilled= 1. The hood sealing air fan &!54! must e o*erating 2. The adEustale dam*ers must e in closed *osition 3. The tem*eratures of the motor windings must e elow themaimum *ermissile le(el 4. The tem*eratures of the motor earings must e elow themaimum *ermissile le(el !. The tem*eratures of the fan earings must e elow themaimum *ermissile le(el  An alarm is gi(en in the *rocess control centerD") whenthe fan earing tem*erature eceeds %5 '". During normal o*eration •

"AF control 9&!552:; is controlled y the suction in the firing #one at 3mm to !mm0" 9&4P35!:.

•

Inlet dam*er9&!&115: is o*en at 155 and the 6FD is controls the motor s*eed.

 At machine sto*; the inlet dam*er remains fully o*en and the 6FD goes to minimum s*eed.

Ot(er loops 1. "ontrol dam*er 9&!115:; 0-,F 9&!522: to F 9&!542: duct; for control of the dew *oint 9)P re
3. "ontrol dam*er 9&!15$:; /DD 9&!512: leedoff /DD gases to ehaust gas chimney. "ontrolled at set *oint of !55mm0" 9&!P152:. 4. "ontrol dam*er 9&!151:; /DDF 9&!512: leedin for control of /DD gases tem*erature in /DD wind oes and fan *rotection; located in duct ao(e the second cooling #one. "ontrolled at aout 455G" 9&4T353:. To maintain Fan manufacturers ad(ised ma o*erating tem*erature 9455G":. The leedin Dam*er o*ens fully in case of emergency sto**age of the fan. !. "ontrol dam*er 9&!152:; If the /DD9&!512: outlet tem*erature &!T12! is too low; at start u* for instance; it can e oosted y leeding *rocess gas from the outlet of the

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0ind o ,ecu*eration Fan &!522 to the suction side of the /*draft Drying Fan y dam*er.9to o*erate at startu* only: $. "ontrol dam*er 9&!153:; 0-,F 9&!522: leedin for fan *rotection; located in end of  the long 0-, manifold. "ontrolled at aout 455 G" 9&!T124:. To maintain Fan manufacturers ad(ised ma o*erating tem*erature 9455G":. This dam*er to o*en fully in case of emergency sto**age of the fan. %. "ontrol Dam*er 9&!15%:; F 9&!542: leed in dam*er for )P; located at inlet. "ontrolled at aout 115 G" tem*erature 9&!T123:. It also maintains Fan Manufacturer  recommended limit of o*erating tem*erature9125G":. This dam*er to o*en u*on *ower failure. 7. mergency )hut off Dam*er &4/151 9&4532: located at P #one in 0-,F9&!522: duct. This will o*erate in case of *ower failure or if grate sto*s. ormally it is fully o*en; on emergency it shuts off to *re(ent F &!542. It is *neumatically o*erated Fail "lose dam*er. 8. *ansion switches9non contact ty*e: 9&4&151A?-: on each side of the discharge end to limit the grate e*ansion. If e*ansion eceeds to set *oint it will tri* the grate. 15. At 25 le(el of Discharge in &3511 the (iratory feeders &%553 K &%554 will start; controlling range will e etween 2545. ii le(el will e at !5  le(el. At this le(el the (irating feeders will o*erate on its maimum and grate will sto*. 11. Two tem*eraturesensors &%T151;&%T152are installed on discharge con(eyor  &%552AIfthe *ellet discharge tem*erature eceeds more than set *oint 915!G": then the water s*ray (al(e&%/151will o*en. Iftem*erature does not decrease elow 985G": second water s*ray (al(e &%/152 will o*en to control the tem*erature. 12. At 45 +)- in &%55! le(el the (iro feeder &%55$ will start and after that it will adEust the s*eed to control the in le(el. -in le(el controlling range will e 45$5. 13. At 45 +)- in &%55! le(el the(iro feeder &7551 will start. It will control the earth layer in &755! le(el etween 35$5 y adEusting the s*eed. At in &755! le(el reaches II 97!: feeding con(eyor &7553;&7554 and the (iro feeder &7551 will tri* immediately. 14. There is a *roduct o(erflow if +)- in &%55! le(el reaches more than 75. If o(erflow chute choes and le(el goes high then discharge con(eyor &%552A and (iro feeders on discharge in &%553;&%554 will tri* immediately.

5.1.5.Associated Ancillar' 'stems The following systems ha(e association with the induration area 1. &rate feed 2. earth +ayer  3. Drile "on(eyor  4. Doule Pendulum Dust 6al(es 9windoes: !. Product andling $. )P Dust andling Page

%. +intel "ooling 0ater  7. -urner Management )ystem 8. Fuel 'il su**ly and heating 15. -urner Purging 9*lant air: 11. -urner "ooling Air fan. 12. Instrument Air com*ressor9s: 13. Plant air com*ressor9s: ,efer to the a**ro*riate Process '*eration K "ontrol document

6. Alarms N o.

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*+,C -C -&0 -&0

Fan *oto$         T$avellin( ($ate                    

-4C -C -8880 A1ove set value A1ove set value ;8881a$ ; 888 L/M Level a1no$*al ;2** -3** -&. */* 'elo5 set value -888 A

'u$ne$s    'u$ne$s 

;7C ;8881a$ ;8881a$ ;8881a$ ;8881a$ ;888 **

Fuel oil lo5 te*+e$atu$e Fuel oil +$essu$e lo5 L P G +$essu$e lo5 Plant ai$ +$essu$e lo5 Inst$u*ent ai$ +$essu$e lo5 Ato*iBin( ai$ +$essu$e lo5

'allin( 1ins   'allin( !is
-set value 8  ;set value 8  ; set value 8  -set value 8  -et value 8 ;6@ =iel!

'in level )i 'in level lo5 Fee! $ate lo5 Fee! $ate )i Moto$ u$$ent 9i(9 G$een +$o!ution Lo5

-4@ to++e!

Moto$ 5in!in( te*+e$atu$e Moto$ 1ea$in( te*+e$atu$e Moto$ Vi1$ations Moto$ 9i(9 u$$ent Moto$ 5in!in( te*+e$atu$e )i(9. Lu1$iation +$essu$e lo5 Lintel 5ate$ level 'e! level lo5 'e! level )i G$ate s+ee! )i G$ate s+ee! lo5 Moto$ u$$ent )i Moto$ to$?ue )i Dis9a$(e 9o++e$ )i level Dust olleto$ not o+e$atin( )#.&

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;set value -set value ;set value -set value ;set value -set value ;set value -set value to++e! to++e! to++e! to++e! -set value i!e t$avel

Fee! $ate lo5 Fee! $ate )i Fee! $ate lo5 Fee! $ate )i Fee! $ate lo5 Fee! $ate )i Fee! $ate lo5 Fee! $ate )i Dust olleto$ not o+e$atin(          Moto$ u$$ent )i Conve=o$ si!e t$avel

Plant ai$ $eeive$ Inst$u*ent ai$ ate$ 1asin

;set value ;set value ;set value

Ai$ $eeive$ +$essu$e lo5   ate$ 1asin lo5 level  etion

P$o!ut !is9a$(e P$o!ut 1in G6.3    Dust olleto$

-set value -4@ ; %3@ to++e!

P$o!ut !is9a$(e te*+e$atu$e )i. P$o!ut 1in level )i P$o!ut 1in lo5 level Dust olleto$ not o+e$atin( )2.&

. Re!uired "o#ic and Instrumentation +.1

,ed -eel and Grate "eed

•

umer of green ed le(el detectors are three in
•

umer of earth layer ed le(el detectors are also three in
•

,ange of le(el detectors is 5  $55mm

•

Install &rate )*eed i i alarm 9setting at 1.$m?min:.

•

Dis*lay 3D gra*h of ed height 9re
+.2 •

Pallet !hange Facilit# +ocal *anel for >Pallet "hangeH at "hangeout station. Mode selection 9local *anel acti(ation: from "entral "ontrol ,oom 0orstation. Page