Burners Czaplinski 2006

Burners - Influence of flame and flame shape on the refractoryliningAlain Czaplinski

WHAT IS COMBUSTION ?

A CHEMICAL REACTION BETWEEN TWO CHEMICAL COMPONENTS WHICH CREATES HEAT

TYPICALLY ONE OF THE COMPONENT IS AIR ( OXYDISING REACTION ), THE SECOND IS CALLED FUEL

GEORG ERNST STAHL ( 1660 1734 ) :

COMBUSTION WAS DUE TO THE PHLOGISTIC COMPONENT IN COAL IN ORDER TO CALCINATE METAL

COAL ( INCLUDING PHLOGISTIC ) => COAL + PHLOGISTIC => FIREMETAL + PHLOGISTIC => CALCINED METAL

IN 1760, BLACK IDENTIFIED FIXED AIR WHICH IS CO2IN 1766, CAVENDISH IDENTIFIED INFLAMMABLE AIR WHICH IS H2

PRIESTLEY IDENTIFIED PHLOGISTIC AIR WHICH IS N2

IN NOVEMBER 1772, LAVOISIER ESTABLISHED THE MASS CONSERVATION PRINCIPLE DURING TIN CALCINATION BY WEIGHTING THE AIR BEFORE AND AFTER THE REACTION

COMBUSTION IS NOT

CALCINATION :

CaCO3 + HEAT ( 1800kJ/kg ) => Ca0 + CO2

BY EXTENSION, CALCINATION MEANS TO BURN AT HIGH TEMPERATURE A MATERIAL IN ORDER TO GET A NEW ONE

PYROLYSIS :

CHEMICAL DECOMPOSITION DUE TO HEAT

COMBUSTION REACTIONS

C + 0 => CO + 111 kJ/mol

CO + 0 => CO2 + 283 kJ/mol

C + 02 => CO2 + 394 kJ/mol

H2 + 0 => H20 + 242 kJ/mol

S + 02 => S02 + 71 kJ/mol

CH4 + 202 => CO2 + 2H20 + 820 kJ/mol

CALORIFIC HEAT VALUE

HEATING VALUE : MEANS THE HEAT QUANTITY OBTAINED WHEN BURNING ONE UNIT OF FUEL

IT IS THE HEAT POTENTIAL OF A FUEL WHICH CAN BE COMPARED WITH OTHERS

HIGH HEATING VALUE ( HHV ) : WATER IS CONSIDERED AS LIQUID (CONDENSATE )

LOW HEATING VALUE ( LHV ) : WATER IS CONSIDERED AS VAPOR

HHV and LHV are expressed in kJ/kg

HHV = LHV + WATER VAPORISATION HEAT

IN PRACTICE, IN ATMOSPHERIC CONDITIONS, WE NEED TO CONSIDER THE LHV AS FLUE GAS TEMPERATURE IS HIGHER THAN 100c

RELATION BETWEEN HHV AND LHV

HHV = LHV + WATER LATENT VAPORISATION HEAT

HHV = LHV + ( %H20 ) x 25 + ( % H ) x 226

% PERCENTAGES IN WEIGHT

IE : HEAVY FUEL OIL LHV = 40100kJ/kg , H20 = 0,95% , H = 11%

HHV = 40100 + (0,95)x25 + ( 11)x226 = 40100 + 24 +2486 = 42610 kJ/kg

6% difference

IE : NATURAL GASLHV = 36500 kJ/Nm3 , H20 = 0% , H = 18%

HHV = 36500 + (0)x25 + ( 18)x226 = 36500 + 4068 = 40568 kJ/Nm3

11% difference

MAIN NOBLE FUEL CLASSIFICATION PER LHV

NATURAL GAZ : 34 000 to 45 000 kJ/Nm3 ( depends on N2 content )

HEAVY FUEL OIL : 40 000 kJ/kg

DIESEL OIL : 43 000 kJ/kg

COAL : ANTHRACITE ( raw basis ) : up to 39 000 kJ/kg STEAM COAL ( raw basis ) : 24 000 kJ/kg to 27 000 kJ/kgLIGNITE ( raw basis ) : 15 000 kJ/kg to 19 000 kJ/kg

PETCOKE ( raw basis ) 33 000 kJ/kg to 36 500 kJ/kg

* Contaminated water negative

* Blast furnace gaz 2 700 kJ/kg

* Dried sewage 8 000 to 15 000 kJ/kg

* Paper, cardboard 13 000 to 17 000 kJ/kg

* tyres 25 000 to 31 000 kJ/kg

* solvents 29 000 to 37 000 kJ/kg

* waste oils 27 000 to 40 000 kJ/kg

* Waste plastics 18 000 to 42 000 kJ/kg

ALTERNATIVE FUELS : TYPICAL LHV VALUES

ALTERNATIVE FUELS : WHY IN A CEMENT PLANT ?

IN EUROPEAN COMMUNITY, CITY WASTES NEEDS FOR INCINERATION :

A RESIDENCE TIME SUPERIOR TO 2 SECOND AT 850c

IN A ROTARY KILN : RESIDENCE TIME IS SEVERAL SECONDS BETWEEN 900c AND 1300 c

A ROTARY KILN IS A PERFECT INCINERATOR WHEREASHES ARE REUSED

DEFINITIONS ABOUT AIR

STOECHIOMETRIC AIR : EXACT AIR QUANTITY REQUIRED TO BURN ONE UNIT OF FUEL ( kg of air/ kg of fuel )

EXCESS AIR LAMBDA : AVAILABLE AIR QUANTITY / STOECHIOMETRIC AIR

LAMBDA > 1 : REAL AIR EXCESS TO ALLOW A COMPLETE COMBUSTION

LAMBDA

OTHER DEFINITIONS :

SPEED OF FLAME : SPEED OF THE FRONT OF FLAME IN THE DIRECTION OF THE MIXING AIR AND FUEL TO BE BURNT NEXT

DEFLAGRATION : IF THE FLAME CAN SPREAD IN A AUTONOMOUS AND SUBSONIC WAY

DETONATION : IN CASE OF DEFLAGRATION, FLAME PROPAGATION AND GAZ DILATATION CAN CREATE A CHOCK WAVE AHEAD OF THE FRONT OF FLAME.THEN COMBUSTION IS CREATED BY PRESSURE INCREASE ( SO TEMPERATURE INCREASE ) AHEAD OF THE FRONT OF FLAME. IT HAPPENS AT ULTRASONIC SPEED GENERATING OVERPRESSURE OF SEVERAL MPa.

DEFINITION OF FLAME LENGTH

THERE ARE SEVERAL DEFINITIONS OF A FLAME LENGTH

DEFINITION 1 : DISTANCE BETWEEN THE BURNER OUTLET TO THE POINT WHERE THE COMBUSTION RATE IS , BY EXAMPLE, 99%

DEFINITION 2 : DISTANCE BETWEEN THE BURNER OUTLET TO THE FURNACE POSITION WHERE THE FLUE GAS TEMPERATURE IS, BY EXAMPLE, 1000c

DEFINITION 3 : DISTANCE BETWEEN THE BURNER OUTLET TO THE POINT WHERE THE FLAME BECOMES UNVISIBLE BY EYE

OTHERS

IN CEMENT INDUSTRY, WE SHOULD USE THE THIRD DEFINITIONAS WE ARE MAINLY INTERESTED IN HEAT EXCHANGE BY RADIATION

BUT WE CANT MEASURE IT

INFLAMMABILITY LIMITS

MAXIMUM AND MINIMUM GAZ FUEL CONCENTRATIONS IN AIR WHERE STABLE COMBUSTION MAY OCCUR

FOR NATURAL GAZ : Lmin is around 5% , Lmax is around 15%FOR ACETYLENE ( C2H2 ) : Lmin is 2,2% , Lmax is 85%( in volume )

MINIMUM INFLAMATION TEMPERATURE : MINIMUM TEMPERATURE AT WHICH SPONTANEOUS COMBUSTION WITH AIR STARTS ( under atmospheric pressure)

FOR METHANE : 580cFOR BUTANE : 420c

FOR COALS : depends on fineness to allow volatile matter inflammation

WHAT IS FLAME TEMPERATURE ?

WE NEED TO SPEAK ABOUT ADIABATIC FLAME TEMPERATURE IN STOECHIOMETRIC CONDITIONS

A COMBUSTION IS ALWAYS CREATING A TEMPERATURE INCREASE ( T ), SO WE NEED TO FIX A REFERENCE TEMPERATURE ( IE AMBIANT AIR )

ADIABATIC MEANS THAT THE SYSTEM IS ISOLATED, ALL THE HEAT CREATED BY COMBUSTION IS TRANSFERRED TO THE STOECHIOMETRIC FLUE GAS

STOCHIOMETRIC CONDITIONS ARE REQUIRED :IN LACK OF AIR, WE CANT REACH THE MAXIMUM FLAME TEMPERATURE.IN EXCESS OF AIR, FLUE GAS ARE IN EXCESS TO ABSORB THE HEAT, THE FLAME

TEMPERATURE IS DECREASING

% OF STOECHIOMETRIC AIR

PEAK OF FLAME TEMPERATURE UNDER STOECHIOMETRIC CONDITIONS

1,0

UNDERSTOECHIMETRIC CONDITIONS :NOT ENOUGH AIR TO BURN THE FUEL

EXCESS AIR CONDITIONS :UNBURNT AIR IS COOLING THE FLAME

ADIABATIC FLAME TEMPERATURE : TYPICAL CURVE PROFILE

SOME ADIABATIC FLAME TEMPERATURES

BLAST OVEN GAS = > +/- 1200c

H2 => 1430c

CH4 = > 1957c

C2H4 => 1560c

C3H8 = > 1980c

C4H10 = > 1970c

STEAM COAL = > +/- 2000c

COAL ANALYSIS

% PROXIMATE ANALYSIS ULTIMATE ANALYSIS

MOISTURE 7.0 C 68.00ASH 18.0 H 2.20VOLATILE MATTER 10.0 S 0.80FIXED CARBON 65.0 N 1.00

O 3.00H20 7.0

ASH 18.0

TOTAL 100.0 100,0

Moisture : difference in weight after drying at 105/110c

Volatile matter : difference in weight after pyrolysis at 900c ( ISO ) or 950c ( ASTM )

Ashes : remaining weight after complete combustion

Fixed carbon : calculated by difference

COAL ANALYSIS

PROXIMATE ANALYSIS ON DIFFERENT BASIS

raw basis as dried dry ash and moisture freeMoisture 7.0 1,0 0.0 0,0 Ash 18.0 19,16 19,36 0,0Volatile Matter 10.0 10,65 10,75 13,33Fixed Carbon 65.0 69,19 69,89 86,67

HHV ( Kj/Kg ) 26,0 27,68 27,96 34,61

Total 100.0 100,0 100,0 100,0

% in weight

HHV is proportional to H20 and ashes, LHV to be calculated from HHV, H20 and H

FOR SOLID FUEL, BASIS OF HEATING VALUE SHOULD BE ALWAYS MENTIONED

KEY POINT : IGNITION OF COAL

IGNITION MECHANISM OF COAL RELIES ON VOLATILE MATTER :

PYROLYSIS AND COMBUSTION OF VOLATILE MATTER => HEATING UP OF AIR AND SOLID FUEL AT BURNER OUTLET

QUANTITY AND QUALITY OF VOLATILE MATTERS ARE THE KEY FACTORS FOR IGNITION

SIMPLE CRITERIA :IGNITION BASED ON VOLATILE MATTER CONTENT

MORE INTERESTING CRITERIAIGNITION BASED ON QUALITY OF VOLATILE MATTER

HHV COAL = HHV FIXED CARBON + HHV VOLATILE MATTER

Calculations made on moisture and ash free basis

IN CEMENT, WE INTRODUCED COAL WHEN TEMPERATURE IS AROUND 800c , WE AVOID THE IGNITION PROBLEMS

COAL REACTIVITY : % VOLATILE MATTER RELEASED VS TEMPERATURE

COAL REACTIVITY : COMBUSTION RATE OF CHAR ( AT 700c + AIR )

IGNITION OF ANTHRACITE COMPARED TO STEAM COAL

0

500

1000

1500

T

e

m

p

e

r

a

t

u

r

e

(

C

)

0

500

1000

1500

0,00 1,00 2,00 3,00 4,00 5,00 6,00 7,00

STEAM COALANTHRACITE OF VIET NAM

COAL CLASSIFICATION (ASTM D388)

8890 7780 7220 6110 5280 4610 kCal/kg

Anthracite

Low vol.Bit.

Mediumvol. bit.

High vol.A bit.

Highvol.

B bit.

Highvol.

C bit.or

Subbit A

SubbitB

SubbitC Lignite

VM/MAF FC/MAF%

HHV WITH INHERENT MOISTURE WITHOUT MINERAL MATTER

40

69

78

86

9298

100

31

22

14

820

60

LOW REACTIVITY

HIGH REACTIVITY

SPECIFICITIES OF COMBUSTION IN CEMENT KILNS

ONE SINGLE BURNERONE VERY LONG AND NARROW FURNACE ( L/D : 10 to 40 )

DIRECT HEAT EXCHANGE WITH CLINKER ( RADIATIONS, CONVECTION )FUELS ASHES ARE INCORPORATED IN CLINKER

ONLY 10% OF COMBUSTION AIR THOUGH THE BURNEREXTREMELY HOT SECONDARY AIR ( 700 TO 1200c ) COMBUSTION EFFICIENCY IS USELY NOT A CRITERIA

STABLE LOADLARGE MIXING OF FUELS


ONE SINGLE BURNER

ONE VERY LONG AND NARROW FURNACE ( L/D : 10 to 40 )

BURNER OUTPUT : UP TO 250 MW ( 5000 tpd, 4,2MJ/kg )=> equivalent to 21tph of Heavy Fuel oil

PRECALCINER KILN : 12 000 tph, 40%/60%, 3MJ/kg clinker=> main burner output is 166MW => precalciner output is 250 MW

POWER GENERATION : TANGENTIAL FIRING

FIRING SYSTEMTANGENTIAL WINDBOW BURNERS

DOUBLE ARCH FIRING CALLED W FLAME

TYPICAL ARCH COAL BURNER

BURNER ARRANGEMENT ON THE ARCH


ONE SINGLE BURNER

BURNER OUTPUT : UP TO 250 MW ( 5000 tpd, 4,2MJ/kg )=> equivalent to 21tph of Heavy Fuel oil

PRECALCINER KILN : 12 000 tph, 40%/60%, 3MJ/kg clinker=> main burner output is 166MW => precalciner output is 250 MW

A KILN BURNER IS SINGLE : RELIABILITY IS A KEY FACTOR

VERY FEW BURNER MANUFACTURERS ON THE WORLD MARKET


ONE VERY LONG AND NARROW FURNACE ( L/D : 10 to 40 )

THE FLAME SHAPE IS A KEY ISSUE TO FIT INSIDE THE NARROW TUNNEL

THE TEMPERATURE PROFILE IS THE MOST IMPORTANT PARAMETER FOR A CEMENT OR LIME PRODUCER

PREMIUM CRITERIA IS : FLAME SHAPE FLEXIBILITY

MULTICHANNELS BURNERS ARE USED IN ROTARY KILNS

MULTI CHANNEL BURNERS : PRINCIPLES

THE THREE CHANNEL BURNER TYPE :

A

AXIAL AIR (ANNULUS)

COAL STREAM

AXIAL AIRSWIRL AIR

Unitherm Cemcon Firing Systems

TEMPERATURE PROFILE (CFD Modelling)

p.a. nozzle setting fully axial controlled long flame

p.a. nozzle setting 35 angle short, hot flame

TEMPERATURE PROFIL :

T"long" flame"short" flame

FOR CEMENT PRODUCERS :BURNER EFFICIENCY IS TO CONTROL THE FLAME TEMPERATURE ALONG THE KILN

FLAME TEMPERATURE : FLAME WITH LIGNITE AND WASTES

FLAME TEMPERATURE : LIGNITE AND WASTES FIRING

MAIN MULTICHANNEL BURNER MANUFACTURERS

COMBUSTION COMPANIES :

PILLARD : THREE CHANNELS BURNER, ROTAFLAM

UNITHERM : UNIGO, UNIGRESS, UNIGAS, MAS

GRECO ENFIL

CEMENT ENGINEERING COMPANIES :

FLS : SWIRLAX, CENTRAX AND DUOFLEX

KHD : PYROJET

UNITHERM MAS BURNER

ONE STABILISER IN THE CENTER

ONE SINGLE AIR CHANNEL

ADJUSTABLE AIR ANGLE DEVICE

ONE 250mbar PA FAN

SOLID and WASTES IN THE CENTER

SWIRL SETTING DEVICE FOR PRIMARY AIR

Unitherm Cemcon Firing Systems

PILLARD ROTAFLAM BURNER


TWO AIR CHANNELS

ADJUSTABLE AIR CROSS SECTIONS

ONE 250mbar PA FAN


PILLARD ROTAFLAM : ADJUSTMENT OF AIR CROSS SECTIONS

FLS DUOFLEX BURNER


TWO AIR CHANNELS MIXED BEFORE BURNER OUTLET

ADJUSTABLE AIR CROSS SECTIONS

ONE 250mbar PA FAN


FLS DUOFLEX BURNER : AIR CROSS SECTIONS ADJUSTMENTS

KHD : PYROJET BURNERS

NO STABILISER IN THE CENTER

COAL CHANNEL BETWEEN TWO AIR CHANNELS

FIXED CROSS SECTIONS

ONE BLOWER FOR AXIAL AIR 450mbar

ONE FAN FOR RADIAL AIR

Jet Air Nozzle Ring

GRECO ENFIL BURNERS

NO FIXED CONCEPT, NO BRAND NAME

CASE BY CASE STUDY

FIXED CROSS SECTIONS

COAL CHANNEL BETWEEN TWOAIR CHANNELS

ONE ROOT BLOWER FOR AIR AT 450mbar

WASTES IN THE CENTER


DIRECT HEAT EXCHANGE WITH CLINKER ( RADIATIONS..)

THE FLAME NEEDS TO BE RADIANT TO IMPROVE THE HEAT EXCHANGE EFFICIENCY

RADIATIONS : HEAT EXCHANGE VIA ELECTROMAGNETIC WAVES ( PHOTONS )

RADIANT HEAT FLUX IS PROPORTIONAL TO : T 4

THE FLAME NEEDS HIGH TEMPERATURE AND HIGH INTERNAL MIXING( NATURAL GAS IS LESS EFFICIENT )


FUELS ASHES ARE INCORPORATED IN CLINKER

IN POWER GENERATION, FLY AND BOTTOM ASHES ARE RECOVERED,BUT REUSING IS VERY DIFFICULT

IN CEMENT KILNS, REUSING IS EASY AS IT IS A PART OF THE FINAL PRODUCT WHICI IS REAL SPECIFIC TO THIS INDUSTRY

IT MAY CREATE LIMITATIONS ( P2O5 , Cl etc ) WHEN FIRING WASTES


PRIMARY AIR IS AMBIANT ( LOW TEMPERATURE ): HIGH %PA = LOW EFFICIENCY

LOW PRIMARY AIR REDUCES ALSO NOx EMISSIONS

LOW PA BURNERS WERE CALLED HIGH EFFICIENCY BURNERS

ONLY 10% OF COMBUSTION AIR THOUGH THE BURNEREXTREMELY HOT SECONDARY AIR ( 700 TO 1200c )

HIGH SPEED PRIMARY AIR IS MIXED WITH LOW SPEED SECONDARY AIRMIXING IS SOMETIMES DIFFICULT,

POSITION OF THE BURNER INSIDE THE KILN SHOULD BE ADJUSTABLE

SECONDARY AIR INJECTION AT BURNER TIP

Secondary Air Mixing Flow pattern velocity in [m/s]

(velocities above 25 m/s are displayed in red)Unitherm Cemcon Firing Systems


USUALLY WITH A RIGHT EXCESS AIR AT KILN OUTLET ( 2% O2 )IS ENOUGH FOR A COMPLETE COMBUSTION

AS RESIDENCE TIME IS LONG ENOUGH

COMBUSTION EFFICIENCY IS USELY NOT A CRITERIA

WITH WASTE FUELS ( SOLID ) ,IT MIGHT BE NECESSARY TO INCREASE THE EXCESS AIR

FOR BURNERS MANUFACTURERS : BURNER EFFICIENCY IS THE COMBUSTION RATE

RELATIONS BETWEEN BRICKS AND BURNER

AFTER 7 DAYS OF OPERATION

RELATIONS BETWEEN BRICKS AND BURNER

AFTER 7 DAYS OF OPERATION

NOTHING TO DO WITH THE BRICKS NOTHING TO DO WITH BURNER DESIGN

BUT A MISTAKE IN BURNER OPERATION

USUAL IGNITION PROCESS :

1) GAZ IGNITOR WITH ELECTRODES

2) LIQUID OR GAZ LANCE

3) SOLID FUEL INJECTION WHEN TEMPERATURE IS OK

4) CHANGE OF ROTATION SPEED

5) MEAL INJECTION

HEATING UP : RISK WITH POOR FUEL OIL PULVERISATION (1)

HEATING UP OF THE KILN WITH HEAVY FUEL OIL (2)

HEATING UP OF THE KILN WITH HEAVY FUEL OIL (3)

NEW LINING AFTER 8 HOURS HEATING UP TO 1000c

RELATION BETWEEN FLAME INTENSITY AND CLINKER

INFLUENCING FACTORS :

CEMENT PRODUCERS ARE FOCUSING ON :CLINKER PARAMETERS:

BURNABILITY INDEXSILICA RATIO

FREE LIMEGRINDABILITY

S02 , ALKALI RECIRCULATIONS etc..

BURNER MANUFACTURERS ARE FOCUSING ON :DIAMETER AND LENGTH OF KILN

TYPE OF PROCESSFUELS TO BE BURNT

KILN THERMAL LOAD IN BURNING ZONE


Q2 /S : HEAT INPUT THROUGH MAIN BURNER DIVIDED BY THE KILN SECTION ( INSIDE BRICKS ) :

CALCULATED WITH : SPECIFIC HEAT CONSUMPTION IN kcal/kg KILN OUTPUTKILN DIAMETER

Example : KILN : 2300 TPD, Diameter 4,6m , precalciner kiln

SPECIFIC HEAT CONSUMPTION : 880 kcal/kg with 65% through the main burner

bricks : B620/B320

Q2 /S = 0,65*(( 2300/24)*880*4)/ ( (4,6-0,44)2* )

Q2 /S = 4033 Gcal/hm2

KILN THERMAL LOAD IMPACT ON LOWER TRANSITION ZONE BRICKS

ONE TENTATIVE OF APPROACH BY CALCULATIONS :

FLS KILN, 5000 TPD, PRECALCINER, DIAMETER 4,75M

FIRST OPERATION KILN 1 : AT 5000 TPD : Q2 / S = 3,8 Gcal/hm2

LTZ : AG 85 0,4 TO 9M , STABLE COATING FROM 12 to 19M=> LIFETIME : 14 MONTHS

SECOND OPERATION KILN 1 : RUNNING AT 6000 TPD, Q2 / S = 4,5 Gcal/hm2

LTZ : AG 85 BETWEEN 0,4 TO 9M, STABLE COATING FROM 9 to 19M=> LIFETIME : 14 MONTHS ( still running )

CONCLUSION : Q2 / S < 4,5 Gcal/hm2

=> NO REAL IMPACT ON BRICK LIFETIME ( in this case )


POLYSIUS KILN WITH PREHEATER , 1800 TPD, DIAMETER 4,6M

FIRST TYPE OF CLINKER : Q2 / S = 4,9 Gcal/hm2

SECOND TYPE OF CLINKER, Q2 / S = 5,4 Gcal/hm2

AG AF BETWEEN 7 TO 16M, stable coating starting from 12/14M

LTZ LIFE TIME : 6 months with relative stable coating

LIFE TIME : 3 months with 2 weeks operation without coating

CONCLUSION : Q2 / S > 5,3 Gcal/hm2

BECOMES CRITICAL WITHOUT COATING


COMPARISON BETWEEN THE KILNS IN Gcal/hm2 :

Q2 / S < 4 : LOW TO NORMAL THERMAL LOAD

4 < Q2 / S < 4, 5 : NORMAL THERMAL LOAD

4,5 < Q2 / S < 5,3 : HIGH THERMAL LOAD

Q2 / S > 5,3 : HIGH TO EXTREME HIGH THERMAL LOAD

1950 1960 1970 1980 1990

3

4

5

1000

2000

3000

5000

6000

7000

8000

4000

hmGcal

2

tpd

specific heat average load in the sintering zone

kiln efficiency

kiln efficiency with precalciner

KILN THERMAL LOAD EVOLUTION


IN BELGIUM :

1640tpd, POLYSIUS PREHEATER KILN , Q2 / S = 3,8 Gcal/hm2

4600tpd, POLYSIUS PRECALCINER, Q2 / S = 4,3 Gcal/hm2

Same fuels , bricks B322/B622 on both kilns

According to the production manager: the flame is stronger on kiln 3 than on kiln 4

Life time of bricks in LTZ : Kiln 3 : RG 85/ RG AF = 9 months hot spotsKiln 4 : AG AF = 12 months ( remaining thickness 150 to 200mm )

THERMAL LOAD IS ONE CALCULATED PARAMETER,BUT FLAME CONTROL IS A NON QUANTIFIED PARAMETER

WHICH IS MORE CRITICAL

GAZ FLAME : WITHOUT CONTROL

)()()/()/()/()/()()()( smskgsmskgNNN

VrQmrVaQmaGxrGxaGx +=+=

)()()/()/()/()/()()()( smskgsmskgNNN

VxrQmrVaQmaGxrGxaGx +=+=

)/()()/(/

hrGcalNGcalNS PGxI =)/()()/(

/hrGcalNGcalN

S PGxI =SPECIFIC FLAME MOMENTUM

BURNER IMPULSE , FLAME MOMENTUM , FLAME INTENSITY :IMAGE OF FLAME HARDNESS

BE CAREFUL, THERE ARE DIFFERENT WAYS OF CALCULATION (with or without fuels streams ) :

FORMULA USED BY LAFARGE, PILLARD ETC..

AXIAL FLAME MOMENTUM : IT IS THE FORCE OF THE AIR STREAMS IN THE KILN AXIS

SPECIFIC FLAME MOMENTUM WITH THE SAME WAY OF CALCULATIONSMUST BE USED FOR COMPARISONS

)/()()/(/

hrGcalNGcalNS PGxI =

)(3)(2

33

33

rirerirerg

=

SWIRL NUMBER : ROTATION INSIDE THE FLAME

BE CAREFUL, THERE ARE DIFFERENT WAYS OF CALCULATION :FORMULA USED BY LAFARGE, PILLARD ETC..

tgGxrGtNN=

)()(Radial air momentum : taking into account the radial air angle

)(3)(2

33

33

rirerirerg

=

)()(2

GxmQmrQmaDe

+=

GxDergGtSN

=

De is the orifice diameter through which can pass a gaseous flow Qv with a momentum of GX

rg : gyration radius of swirl channel

TYPICAL VALUES

LOW NOx GENERATION BURNERS : LOW PRIMARY AIR BURNERS

SPECIFIC AXIAL AIR MOMENTUM : 3 to 5 N / MWSWIRL : 0,4 to 0,5PRIMARY AIR PERCENTAGE : 4 to 8%

HIGH IMPULSE BURNER : SHORT FLAME BURNERS

SPECIFIC AXIAL AIR MOMENTUM : 8 to 12 N / MWSWIRL : 0,1 to 0,2PRIMARY AIR PERCENTAGE : 8 to 12%

)()()/()/()/()/()()()( smskgsmskgNNN


PROBLEMS WITH HIGH IMPULSE BURNERS FOR BRICKS

WITH HIGH IMPULSE LOW OR IMPULSE BURNERS : THE THEORITICAL THERMAL LOAD IN THE BURNING SECTION ( Q2 / S ) REMAINS THE SAME

)()()/()/()/()/()()()( smskgsmskgNNN


BUT THE HEAT TRANSFER PROCESS IS DIFFERENTIE THE TEMPERATURE PROFIL IS DIFFERENT

THE PROBLEM FOR BURNER MANUFACTURERS WAS TO COMPACT THE FLAME VOLUME :IN THE PAST, THE FLAME WAS LONG AND SHARP

OR SHORT AND LARGE

BURNER MANUFACTURERS HAD TO WORK ON NEW DETAILED DESIGNS( BY KEEPING OPERATING PRINCIPLES )

FOR FIRING PETCOKE AND ALTERNATIVE FUELS THEY SHOULD CALLED THEM MAS AF, PYROJET AF, ROTAFLAM AF etc..

SINTERING ZONE, FLAME SHAPE WITH LOW IMPULSE BURNER

WITH HIGH IMPULSE BURNER

~16 m Flame !!

~23 m Flame

!/!

HOLCIM IN SWITZERLAND : CHANGE OF FLAME LENGTH

HIGH IMPULSE BURNER : IMPACT ON SINTERING ZONES BRICKSSTABLE COATING IS THE BEST PROTECTION OF THE BRICKS IN SINTERING ZONE

WITH HIGH IMPULSE BURNERS, THE SINTERING ZONE IS SHORTENED WHICH MAY CREATE PROBLEMS IN THE SELECTION OF BRICKS IN THIS ZONE

SINCE COMMISSSIONING, STABLE COATING ENDS AT 19/20M

LIFE TIME OF RG 85 BETWEEN 19 TO 29M : 7 TO 9 MONTHS

REPLACED WITH ALMAG 85 : LIFE TIME 1 YEAR ( running at 6000 tpd )

5000 TPD ( 4,75 * 74,2m ), FLS PRECALCINER KILNS WITH HIGH IMPULSE DUOFLEX BURNER

AT THE DESIGN STAGE THE FOLLOWING SELECTION WAS MADE WITH FLS :

0 to 0,4M : KRONEX 850,4 to 9M : ALMAG 85

9 to 29M : REFRAMAG 8529 to 41M : ALMAG 85

LAVA LIKE COATING : OVERHEATING

PROBLEM OF RAW MATERIAL PREPARATION ( IRON ORE ..)

PROBLEM OF BURNER ADJUSTMENT :LOCAL WEAR : ORIENTATION OF BURNERFOR SOME METERS : HEAT INPUT IS TOO HIGH

COMBUSTION : IMPACT ON UPPER TRANSITION ZONE AND UPSTREAM BRICKS

MAIN IMPACT, AS THE SINTERING MAY BE SHORTENED,THE POSITION OF THE UTZ IS CHANGED

SELECTION ON THE BRICKS HAS TO FOLLOW THIS NEW POSITION

IF THE COMBUSTION OF SOLID FUELS IS NOT MASTERED IN THE FLAME ( INSUFFICIENT MIXING, TOO COARSE etc.. )

SOLID FUELS CAN FINISH BURNING ON THE BRICKS

LOCAL REDOX CONDITIONS ON THE BRICKS

PROBLEMS WITH HIGH IMPULSE BURNERS FOR BRICKS

)()()/()/()/()/()()()( smskgsmskgNNN


BURNER MANUFACTURERS HAD TO WORK ON NEW DETAILED DESIGNS

( BUT THEY KEPT THE BASIC PRINCIPLES OF OPERATION )

FOR FIRING PETCOKE AND ALTERNATIVE FUELS

WE COULD CALLED THEM MAS AR, PYROJET AR, ROTAFLAM AR etc..

HOLCIM UNTERVARZ CEMENT PLANTVision of a new mega burner

Household waste

Coal

Paper

Carboard

Wood

Waste oil

Contaminated water

Tetra pack

Plastic waste

Liquid waste

Heavy fuel oil Low calorific gas

Distilation residues

ROTAFLAM 125 MW for CEMENTOS APASCO / HOLCIM / Mexico

Axial air channel

Radial air channel

Petcoke channel: 14.000 kg / h

Solid waste: 9.000 kg / h

Natural gas: 6.240 Nm/ h

Heavy fuel oil: 11.300 kg / h

Waste oil: 9.170 kg / h

WASTE FUEL FIRING : REAR PART OF A UNITHERM MAS BURNER

MIXING OF ALTERNATIVE FUEL IN BURNER CENTER

ROTAFLAM FLAME ADJUSMENT WITH A TEST TEST BURNER

ROTAFLAMROTAFLAM SMALL SCALE TESTSMALL SCALE TEST

ROTAFLAM CFD SIMULATION WITH CFD SIMULATIONQ AIR RADIAL = 840 Nm3/h Q AIR RADIAL = 5700 Nm3/hQ AIR AXIAL = 7000 Nm3/h Q AIR AXIAL = 2700 Nm3/h

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Previous Design:1) Long axial excess at burner tip2) Divergent axial air outlet3) 45 Divergence of swirl air4) 40 Swirl angle for swirl airPrimary air pressure: 160200 mbarPrimary air amount: 6-8%Split Axial / Swirl: 40 / 60 Axial impulse: 2,8-3,8 N/MWSwirl number: 0,4-0,5

New Design:1) Minimum axial excess at burner tip2) Axial air outlet axis parallel 3) Reduced divergence of swirl air4) Reduced swirl angle of swirl airPrimary air pressure: 250 mbarPrimary air amount: 8-12%Split Axial / Swirl: 65 / 35 Axial impulse: 8-12 N/MWSwirl number: 0,1-0,2

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ROTAFLAM TIPS DESIGN MODIFICATIONS

ISFAHAN CEMENT : GAZ BURNER WITHOUT CONTROL ( VERY LOW IMPULSE )

ISFAHAN : MULTICHANNEL GAZ BURNER( LOW IMPULSE )

ISFAHAN : HIGH IMPULSE BURNER

COMPARISON OF TWO FLAMES WITH MULTICHANNELS BURNERS

LOW IMPULSE WITHOUT CONTROL HIGH IMPULSE UNDER CONTROL

Burners - Influence of flame and flame shape on the refractoryliningWHAT IS COMBUSTION ?COMBUSTION IS NOT COMBUSTION REACTIONSCALORIFIC HEAT VALUERELATION BETWEEN HHV AND LHVMAIN NOBLE FUEL CLASSIFICATION PER LHVALTERNATIVE FUELS : WHY IN A CEMENT PLANT ?DEFINITIONS ABOUT AIR OTHER DEFINITIONS :DEFINITION OF FLAME LENGTHINFLAMMABILITY LIMITSWHAT IS FLAME TEMPERATURE ?SOME ADIABATIC FLAME TEMPERATURESCOAL ANALYSISCOAL ANALYSISIGNITION OF ANTHRACITE COMPARED TO STEAM COALSPECIFICITIES OF COMBUSTION IN CEMENT KILNSSPECIFICITIES OF COMBUSTION IN CEMENT KILNSSPECIFICITIES OF COMBUSTION IN CEMENT KILNSSPECIFICITIES OF COMBUSTION IN CEMENT KILNSTEMPERATURE PROFIL :FLAME TEMPERATURE : FLAME WITH LIGNITE AND WASTESFLAME TEMPERATURE : LIGNITE AND WASTES FIRINGMAIN MULTICHANNEL BURNER MANUFACTURERS UNITHERM MAS BURNERSWIRL SETTING DEVICE FOR PRIMARY AIRPILLARD ROTAFLAM BURNERPILLARD ROTAFLAM : ADJUSTMENT OF AIR CROSS SECTIONSFLS DUOFLEX BURNERFLS DUOFLEX BURNER : AIR CROSS SECTIONS ADJUSTMENTSKHD : PYROJET BURNERSGRECO ENFIL BURNERS SPECIFICITIES OF COMBUSTION IN CEMENT KILNSSPECIFICITIES OF COMBUSTION IN CEMENT KILNSSPECIFICITIES OF COMBUSTION IN CEMENT KILNSSECONDARY AIR INJECTION AT BURNER TIPSPECIFICITIES OF COMBUSTION IN CEMENT KILNSRELATIONS BETWEEN BRICKS AND BURNERRELATIONS BETWEEN BRICKS AND BURNERHEATING UP : RISK WITH POOR FUEL OIL PULVERISATION (1)HEATING UP OF THE KILN WITH HEAVY FUEL OIL (2)NEW LINING AFTER 8 HOURS HEATING UP TO 1000cRELATION BETWEEN FLAME INTENSITY AND CLINKERKILN THERMAL LOAD IN BURNING ZONEKILN THERMAL LOAD IMPACT ON LOWER TRANSITION ZONE BRICKSKILN THERMAL LOAD IN BURNING ZONEKILN THERMAL LOAD IN BURNING ZONEKILN THERMAL LOAD IN BURNING ZONEGAZ FLAME : WITHOUT CONTROLTYPICAL VALUESPROBLEMS WITH HIGH IMPULSE BURNERS FOR BRICKSHIGH IMPULSE BURNER : IMPACT ON SINTERING ZONES BRICKSCOMBUSTION : IMPACT ON UPPER TRANSITION ZONE AND UPSTREAM BRICKSPROBLEMS WITH HIGH IMPULSE BURNERS FOR BRICKSWASTE FUEL FIRING : REAR PART OF A UNITHERM MAS BURNERMIXING OF ALTERNATIVE FUEL IN BURNER CENTERROTAFLAM FLAME ADJUSMENT WITH A TEST TEST BURNERROTAFLAM CFD SIMULATION WITH CFD SIMULATIONQ AIR RADIAL = 840 Nm3/h Q AIR RADIAL = 5700 Nm3/hISFAHAN CEMENT : GAZ BURNER WITHOUT CONTROL ( VERY LOW IMPULSE )ISFAHAN : MULTICHANNEL GAZ BURNER ( LOW IMPULSE )ISFAHAN : HIGH IMPULSE BURNERCOMPARISON OF TWO FLAMES WITH MULTICHANNELS BURNERS

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Burners Czaplinski 2006