unitherm mas-sw gas burner staff-training [compatibility mode]

M.A.S. Burner TRAINING

Content

• M.A.S. burner design• Flame control by M.A.S. burner • Burning of

• Natural gas •Trouble shooting

• Position of the Burner • Service and maintenance

Unitherm Cemcon Firing Systems

Company Experience


Establishment- 1949

Field of activity- engineering, production and installation of firing systems for industry and power stations

Experience in rotary kiln burners- more than 300 pcs.

1992- technological breakthrough: development of a new burning system generation called M.A.S. (Mono Airduct System)

1997- reduction of product scope to firing equipment for cement industry

At the moment UNITHERM-CEMCON is one of the leading manufacturers of firing systems in the cement industry. Until now numerous M.A.S. burners all over the world have been supplied and commissioned to the full satisfaction of our customers. The excellent operational experiences and the low NOx levels convinced major cement producers to choose the M.A.S. burner for replacement and for new plants as well.

Kiln capacity, heat consumption and clinker quality are defined by:


1. Correct composition of raw meal

1.1 Chemistry Burnability

1.2 Meal fineness

2. Correct burning conditions

2.1 Fuel input and fuel distribution (kiln-calciner) ProcessKiln atmosphere (oxidizing) control

2.2 Kiln temperature profileflame shape control---burner design

2.3 Clinker residence timeburner position in kiln

2.4 Clinker cooling

M.A.S.® -Rotary Kiln BurnerBasic design

Primary air inlet

Flame setting devicewith scale

Primary (MAS) air damper

Outer jacket tube

Flexible swirl device

Nozzle outstream system

Coal dust inlet

Flexible air nozzles system for flame shape adjustment

Patent No: 0642645


Central air damper

M.A.S.® -Gas Rotary Kiln Burner


Swirl setting device

M.A.S.- main air

Central air


3 Stages of clinker burning optimisation with M.A.S. burner

1st Stage: Control of flame shape by flame setting device 2nd Stage: Control of combustion intensity by adjustment of the M.A.S.-air

pressure 3rd Stage: Control of flame core temperature by adjustment of the central

air pressure


1st Stage: Control of flame shapeby flame setting device

1st Stage: Control of flame shape


by flame setting device


Jets flow pattern

Jet flow Ring channel flow

nozz

le

gap

m/s

gap

nozz

le

nozz

le

m/s

ring channelSS

Burner NozzleM.A.S. - system

Burner Nozzle traditional three channel burner (basic)

as

ap

e

l

ap

asap

TT

nD

XmM

MM

,

,

,

,, 2

as

ap

e

l

ap

asap

TT

DXm

MMM

,

,

,

,, 2

The mixing zone for jets flow is shorter proportionally n1/2

n- jets number


FLAMEFLAME

FLAME SHAPE

SHORTLONG 1 2 3 4 5 6 7 8 9FLAMEFLAME

FLAME SHAPE

SHORTLONG 1 2 3 4 5 6 7 8 9



FLAMEFLAME

FLAME SHAPE

SHORTLONG 1 2 3 4 5 6 7 8 9

medium-sized flame narrow, long flamewide, short flame

2nd Stage: Control of combustion intensity


M.A.S. air damper M.A.S. air pressure

by adjustment of the M.A.S.-air pressure

2nd Stage: Control of combustion intensity


800

1000

1200

1400

1600

1800

2000

high pressure 50 mbarhot, short flame

medium pressure 30-50 mbar

low pressure < 10-20 mbarsoft, long flame

kiln length

Flam

e te

mpe

ratu

re, °

C

by adjustment of the M.A.S.-air pressure

3rd Stage: Control of flame core temperature


Central air damper

Central air pressure

by adjustment of the central air pressure


By increasing the central-air pressure, the flame gets stable but the temperature drops in the flame root, close to the burner head.



Path lines of central air colored by temperature [k]; note: no stabilizing swirl on l.h.s

Central air pressure 10 mbar Central air pressure 60 mbar




Contours of temperature [k]

Central air pressure 10 mbar Central air pressure 60 mbar



Flame root temperature

central air pressure, mbar


NOx-emission

0 10 20 30 40 50 60 70 80



Initial settings for medium-sized flame

Fuels in operationPressure of M.A.S.

– airM.A.S.

swirl numberPressure of central

air

mbar Setting on scale mbar

Natural gas 40-50 2-3 20-30

Light fuel oil 100 – 130 3 – 5 40 – 150

Heavy fuel oil 110 -140 3 – 5 40 – 150

Liquid secondary waste fuel oils 100 -140 3 – 5 40 – 150

Coal dust – high volatile 120– 160 4 – 6 40 – 150

Coal dust – low volatile 150 – 200 4 – 6 40 – 150

Solid secondary waste fuels 120 – 180 4 – 6 40 – 150



Initial settings for narrow, long flame

Fuels in operation Pressure of M.A.S. – air

M.A.S.swirl number

Pressure of central air


Natural gas 10-30 0– 1 10-20

Light fuel oil 70 1 – 2 40 – 150

Heavy fuel oil 70 – 100 2 – 3 40 – 150

Liquid secondary waste fuel oils 70 – 100 2 – 3 40 – 150

Coal dust – high volatile 100 – 120 2 – 3 40 – 150


Solid secondary waste fuels 100 – 120 3 – 4 40 – 150



Initial settings for wide, short flame

Fuels in operation Pressure of M.A.S. – air

M.A.S.swirl number

Pressure of central air


Natural gas 50-70 3-5 50-60

Light fuel oil 160 – 200 6 – 7 40 – 150

Heavy fuel oil 180 – 220 6 – 7 40 – 150

Liquid secondary waste fuel oils160 – 220 6 – 8

40 – 150

Coal dust – high volatile160 – 220 5 – 8

40 – 150


Solid secondary waste fuels180 – 220 6 – 8

40 – 150

Burner position in rotary kiln


- especially for rotary kiln with grate cooler a proper axial position of the burner is very important!- 20 cm movement of the burner, moves the sinter zone up to 1m!- sometimes NOx - emissions depends on burner position drastically!- the clinker mass composition as well clinker characteristics depend on length of the cooling zone within the kiln, means also defined by burner axial position. We recommend to keep 1200-1250°C clinker temperature at the kiln edge

Temperature [K] Velocity [m/s]

Burner position in rotary kiln with grate cooler


Initial position X=0for petcoke, solid secondary fuel, coal- following kiln axisfor natural gas or fuel oil- turn more horizontal (rotate around fix point) up to

maximum 3% less as kiln slope

Burner position in rotary kiln with satellite coolers


Initial position X=1000for petcoke, solid secondary fuel, coal- following kiln axisfor natural gas or fuel oil- horizontal (rotate around fix point)

Burner position in rotary kiln


Further optimisation

-move the burner tip to the clinker-keep the flame away from the coating -find the best axial position of the burner:

General considerations to burner axial position

-burner tip deep inside the kiln >> 0,5 m-risk of reduced kiln capacity and high flue gas temperature at kiln inlet-more straight flame -better fuel ignition -reduced risk of ring formation at kiln outlet

-burner tip inside the kiln < 0,5 m (usual position)-increase of kiln capacity and reducing of the flue gas temperature at kiln inlet-risk of uneven flame due to kiln outlet eddy (high turbulence of sec. air)-worse fuel ignition-risk of ring formation at kiln outlet or snowman in cooler

Trouble shooting


Coating ring at kiln discharge

1.1 Move the burner into the kiln with 20 cm steps1.2 Adjust more soft, long flame by swirl setting device1.3 Decrease central air pressure1.4 Decrease M.A.S.-air pressure

Trouble shooting


Permanent coating ring at the beginning of the sinter zone

1.1 Change the soft long flame to short hot flame each 4-8 hours1.2 For example:

Long flame : flame setting device Pos.0-2Short flame: flame setting device Pos.3-5

Trouble shooting


Poor clinker burning, high free lime content in clinker, high CO-content in flue gas

1.1 Increase the M.A.S.-air pressure

1.2 Find the maximum flame core temperature with central air pressure

1.3 Adjust wide, short flame by flame setting device

1.4 Check oxygen content in flue gas and pressure difference through the kiln. Increase the secondary air flow.(If I.D. fan doesn‘t have sufficient power, decrease tertiary air flow)

Trouble shooting


Brown clinker, reducing burning condition

1.1 Check oxygen content in flue gas and pressure difference through the kiln. Increase the secondary air flow.(If I.D. fan doesn‘t have sufficient power, decrease tertiary air flow)

1.2 Increase pressure of the M.A.S.-air and central air

1.3 Change the position of the burner tip in kiln

1.4 Adjust soft, long flame by flame setting device

Trouble shooting


High kiln shell temperature, poor coating

1.1 Adjust soft, long flame by flame setting device

1.2 Decrease the M.A.S.-air pressure

1.3 Decrease the central air pressure

1.4 Decrease the secondary air flow with I.D. fan

1.5 Use the outer cooling of kiln shell with auxiliary fans

Trouble shooting


High kiln shell temperature, poor coating

1.6 Change chemistry of the raw meal

COATING CONDITIONS

86

88

90

92

94

96

98

1,5 2 2,5 3 3,5 4

Silica Ratio

Lim

e sa

tura

tion

fact

or

Hard to burn clinkerDifficultes to form coating

Easy to burn clinkerPossible coating ring formation

Normal

Normal

Trouble shooting


To remove more sulfur with clinker (clogging problem)

1.1 Adjust more hot flame

1.2 Increase oxygen content of 1-3%– more air through the kiln line

Parameters affecting NOx:

• Burning zone temperature• Free lime• LSF• Secondary air temperature• Sec.air flow characteristics

(cooler type)• Thermal kiln loading• Kiln design –staged

combustion in calciner• Fuel grinding size and

volatiles content• Burner tip position in kiln

Pyroprocess


Trouble shooting

Parameters affecting NOx:

• Fuel surrounded by primary air (staged combustion)

• Low primary air amount (momentum)

• Close fuel ignition distance• Mixing intensity of fuels (swirl

number)• Burner settings (avoid

oxygen inside flame root)

Burner design


Typical low NOx design

Trouble shooting

Impact of Central Air on NOx

Primary Air Pressure: 150mbar

Central Air Pressure: 25 mbar

NOx (Kiln Inlet): 1300 mg/m³

Primary Air Pressure: 150mbar

Central Air Pressure: 125 mbar

NOx (Kiln Inlet): 2700 mg/m³


Trouble shooting

Trouble shooting


Decreasing of NOx Emissions

1.1 Decrease M.A.S.-swirl on the swirl setting device to a narrow, long flame shape

1.2 Decrease pressure of the M.A.S.-air

1.3 Adjust pressure of central-air (try the upper and lower limit)

1.4 Increase coal-dust injection velocity

1.5 For solid secondary fuel burning - decrease pressure of Pneumoswirl-air

1.6 Change the position of the burner tip in kiln

1.7 Decrease temperature of secondary air (if possible)

Service and Maintenance


Daily inspections

During operation, the rotary kiln firing equipment must be inspected at least once per working shift and at least the following controls carried out:

• Check functioning of the burner and visible damage or defects• Check flame shape• Visual check of burner insulation• Check equipment for sealed tightness (flange and tube connections, etc.)• Check functioning of operating displays (thermometer, pressure gauges,

flow control instruments, etc.)• Check equipment for suspicious sounds and vibrations



Periodical inspectionsThe following inspections should be carried out about every 3 months, or in the case of a plant standstill:

• Inspection of burner insulation;• Inspection of the all burner / lance nozzles for wear or deposits; • Inspection of input pipe at the pulverized coal connection and the

centering ribs for the coal dust nozzle for wear and tear• Inspection of the flexible flame setting device for smooth running• Inspection of oil / gas and air hoses• Inspection of the smooth functioning of fittings and gears• Inspection of bearings lubricated with oil and grease, and the carrying

out of service work in accordance with detailed descriptions of devices• Inspection of the solid secondary fuel channel for wear or deposits



Replacement of the nozzlesFor dismantling push the bolts of the nozzle wrench in the corresponding holes located on the nozzle and unscrew the nozzle.When the nozzle is loose, take it off by unscrewing the last few turns by hand.

Unscrew with nozzle wrench Take off nozzle by hand



Replacement of the baffle plateTo replace the baffle plate the innermost nozzle must be screwed off first,because the baffle plate is clamped between this innermost nozzle and inside located bolts.When the innermost nozzle is dismantled, take out the baffle plate by hand

innermost nozzle is dismantled take out the baffle plate

ReferencesM.A.S.-burners have been successfully operating in a lot of cement plants over the world


unitherm mas-sw gas burner staff-training [compatibility mode]

Documents

clinker burning

solid secondary

parameters

secondary

combustion

swirl number

flame setting

primary air