gs iron making21.09.10 ocean -

8/7/2019 GS Iron Making21.09.10 ocean -

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Gas SafetyGas Safety

InIn

Iron MakingIron Making


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Working of a Blast FurnaceWorking of a Blast Furnace

TheThe purposepurpose ofof aa BlastBlast FurnaceFurnaceisis toto chemicallychemically reducereduce andandphysicallyphysically convertconvert ironiron oxidesoxidesintointo liquidliquid ironiron calledcalled "hot"hot metal"metal"..

contdcontd..


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1)1) 3 Fe2O3 + CO = CO2 + 2 Fe3O43 Fe2O3 + CO = CO2 + 2 Fe3O4

Begins at 850Begins at 850 F / 460F / 460 CC

2) Fe3O4 + CO = CO2 + 3 FeO2) Fe3O4 + CO = CO2 + 3 FeOBegins at 1100Begins at 1100 F / 600F / 600 CC

3) FeO + CO = CO2 + Fe or3) FeO + CO = CO2 + Fe or

FeO + C = CO + FeFeO + C = CO + FeBegins at 1300Begins at 1300 F / 700F / 700 CC

Chemical ReactionsChemical Reactions


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Blast Furnace OperationBlast Furnace Operation

Raw Blast Furnace GasRaw Blast Furnace Gas

Dust CatcherDust Catcher

Gas CleaningGas Cleaning

PlantPlant

Cleaned BF GasCleaned BF Gas

SlagSlagSGPSGP Hot MetalHot Metal

SMSSMS

DustDust

SinteringSintering

PlantPlantDustDust

55--10 mgm/m310 mgm/m3

100100--250 gm/m3250 gm/m3

Blast FurnaceBlast Furnace


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Cleaning of Raw BF GasCleaning of Raw BF GasB.F.

DUST

CATCHER

SCRUBBER

A-1 A-2 A-3

T.A.

ESP-1 ESP-2

U SEAL

B.F. GASNETWORK

EQUALISING

LINE

DIA. 700 MM


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410 m /hr

40 m /hr

ater inlet

as inlet

as outlet

6.

0.100bar,g

5 g/nm moisture

ater outlet

642 nm /hr

55

iness

650 m3/hr.

300,000nm3/hr

1.8 bar,g200 C

content

TRT not in operation,normal operation

N S

NIN

P NT OF

B.F. -

BSP


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TYPICAL ANALYSIS OF STEELTYPICAL ANALYSIS OF STEELPLANT GASESPLANT GASES

S.NO.S.NO. CONSTITUENTSCONSTITUENTS B.F.GASB.F.GAS COKE OVENCOKE OVEN

GASGAS

L.D.CONVERTERL.D.CONVERTER

GASGAS

Combustible partCombustible part

1.1. Carbon MonoxideCarbon Monoxide 1919--21%21% 8.7%8.7% 5555 60 %60 %

2.2. HydrogenHydrogen 3%3% 59.2%59.2% 2.4%2.4%

3.3. MethaneMethane -- 24.4%24.4% --

Non combustible partNon combustible part

1.1. NitrogenNitrogen 54.9%54.9% 2.1%2.1% 22.4%22.4%

2.2. Carbon dioxideCarbon dioxide 19.8%19.8% 3.2%3.2% 19.2%19.2%

3.3. OxygenOxygen 0.2%0.2% 0.3%0.3% 0.8%0.8%

NoteNote :: Gas Composition may vary from one plant toGas Composition may vary from one plant toother plantother plant


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PROPERTIES OF GASESPROPERTIES OF GASESS.NO.S.NO. PROPERTIESPROPERTIES B.F.GASB.F.GAS COKE OVEN GASCOKE OVEN GAS L.D.GASL.D.GAS

1.1. Explosive rangeExplosive range43%43%--74%74% 66--30%30% 20%20%--70%70%

ExplosiveExplosive Highly ExplosiveHighly Explosive ExplosiveExplosive

2.2.

DensityDensity1.33 Kg/Nm1.33 Kg/Nm33

Heavier than airHeavier than air

0.46 Kg/Nm0.46 Kg/Nm33

Lighter than airLighter than air

1.37 Kg/Nm1.37 Kg/Nm33

Heavier thanHeavier than

airair

3.3. Calorific valueCalorific value 773 KCal/NM773 KCal/NM33 4300 KCal/NM4300 KCal/NM331800 TO 21001800 TO 2100

KCal/NMKCal/NM33

4.4. ToxicityToxicity Very PoisonousVery Poisonous SlightlySlightly

poisonouspoisonous

DeadlyDeadly

poisonouspoisonous

5.5. ColourColour ColourlessColourless ColourlessColourless ColourlessColourless

6.6. OdourOdourOdourlessOdourless

Having smell ofHaving smell of

HH22SS andand

naphthalenenaphthalene

OdourlessOdourless

7.7. Flame colourFlame colour BlueBlue YellowYellow BlueBlue


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GAS HAZARDOUSAREA IN B.F.GAS HAZARDOUSAREA IN B.F.

Category I area: Extremely hazardousCategory I area: Extremely hazardousareasareas

Category II area: Very hazardous areasCategory II area: Very hazardous areas

Category III area: Hazardous areasCategory III area: Hazardous areas


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CategoryCategory --IIAREA IN B.F.AREA IN B.F.

It Includes:It Includes:

Furnace top bleeders and platformFurnace top bleeders and platform Dust catcher top bleeders and platform,Dust catcher top bleeders and platform,

Dust catcher at the time of deDust catcher at the time of de--dustingdustingAll the jobs and repairs like GoggleAll the jobs and repairs like Goggle

plates operation, Blanking/Deblanking,plates operation, Blanking/Deblanking,

Cleaning of impulse line etc.Cleaning of impulse line etc. Furnace shell area.Furnace shell area.


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Safety Precautions in Category I areasSafety Precautions in Category I areas

Protocol is must (wherever reqd.)Protocol is must (wherever reqd.)Clearance to be obtained on aClearance to be obtained on a

prescribed formprescribed formUse of breathing apparatus (Gas Mask)Use of breathing apparatus (Gas Mask)is recommendedis recommended

Use of CO detectors is a mustUse of CO detectors is a mustWork in groupsWork in groupsWind indicatorsWind indicators


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CategoryCategory --IIII area in B.F.area in B.F.

It Includes:It Includes:All platforms around shaft of the furnace.All platforms around shaft of the furnace. Distributor platform.Distributor platform.

Lubricating rooms near the distributor.Lubricating rooms near the distributor. Work on slag holes.Work on slag holes. Repair jobs inside the inter bell spaceRepair jobs inside the inter bell space

during shortduring short--downs.downs. Stove platforms.Stove platforms. Gas Cleaning PlantGas Cleaning Plant-- All EquipmentsAll Equipments


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Safety Precautions in Category II areasSafety Precautions in Category II areas

Protocol to be prepared for cutting/Protocol to be prepared for cutting/welding jobwelding job

CO sampling must be doneCO sampling must be doneClearance to be obtained on a prescribedClearance to be obtained on a prescribed

formform

Use of breathing apparatus (Gas Mask) isUse of breathing apparatus (Gas Mask) isrecommendedrecommendedUse of Personal CO monitors must beUse of Personal CO monitors must be

ensuredensured


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CategoryCategory --IIIIIIArea in B.F.Area in B.F. StairStair--case from ground to the top of thecase from ground to the top of the

furnace.furnace.

Dust catcherDust catcher Foundation area of the furnace.Foundation area of the furnace. Stoves under repairs.Stoves under repairs.

Control roomsControl rooms Furnace hearth platforms, near slag holesFurnace hearth platforms, near slag holesand tuyeres , cast house.and tuyeres , cast house.

LIVE

Gas line and equipments.LIVE

Gas line and equipments.


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Safety Precautions in Category IIISafety Precautions in Category IIIareasareas

CO sampling must be doneCO sampling must be done

Use of Personal CO monitors must beUse of Personal CO monitors must beensuredensured

Protocol to be made for cutting/Protocol to be made for cutting/welding jobswelding jobs


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Possibilities of gas exposure in GCP ofPossibilities of gas exposure in GCP ofBlast FurnacesBlast Furnaces

Breaking of Water seal inBreaking of Water seal in

1.1.SCRUBBERSCRUBBER 2.ATOMISERS2.ATOMISERS

3.ESPs3.ESPs 4.Float Chambers4.Float Chambers

5.Drain pot5.Drain pot Breaking of Water USeal of Clean gasBreaking of Water USeal of Clean gas

collectorcollector

S

hell plate leakages ofS

crubber,S

hell plate leakages ofS

crubber,Atomizers and Throttle Assemble.Atomizers and Throttle Assemble.

Improper Closing of winch operatedImproper Closing of winch operatedbleedersbleeders

Contd.Contd.


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From PreFrom Pre--slideslide

Unburned gas released from ExcessUnburned gas released from Excess gasgas

burnersburners Gas leakages from adjacent pipelineGas leakages from adjacent pipeline Improper Closing of bleedersImproper Closing of bleeders

Uncovered slime channelsUncovered slime channels During nozzle flushing of scrubber,During nozzle flushing of scrubber, atomisersatomisers& T.A.& T.A.

During water level checking of GCPDuring water level checking of GCPequipmentequipment


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DUST

CATCHER

CUTOFF VALVEWINCH

OPERATED

BLEEDER

DUST

BF GAS

TO GCP SCRUBBER

BF GAS


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RAW GAS LINE

4 WATER COLLECTOR

9 NOZZLES IN EACH

WATER COLL.

SCRUBBER

w t r

A1A2 A3

EQUALISING

VALVE

BLEEDER

STEAM


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SCRUBBER

FLOAT

CHAMBER

SCRAPERROD

DRAINVALVE

GAS VALVE

WATERVALVE

T r ttl


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SCRUBBER ATOMISER


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THROTTLE ASSEMBLY

W t r

c ll ct r


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SAIL: Bhilai Steel Plant 23

Carbon Monoxide GasCarbon Monoxide GasExposureExposureCarbon MonoxideCarbon MonoxideGas ExposureGas Exposure


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SAIL: Bhilai Steel Plant 24

DizzinessDizziness

HeadacheHeadache

Mental dullnessMental dullness

Yellowness in front ofYellowness in front ofeyeseyes

Tightness in chestTightness in chest

Weakness in limbsWeakness in limbs VomitingVomiting

UnconsciousnessUnconsciousness


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First aid practices are:First aid practices are:First aid practices are:First aid practices are:

Do not become panic.Do not become panic.

Take the victim in fresh air .Take the victim in fresh air .

Loose tight fitting clothes.Loose tight fitting clothes. If conscious, take longer breath.If conscious, take longer breath.

If unconscious, take victim to theIf unconscious, take victim to the

nearest medical centre.nearest medical centre.

Provide mechanical /artificialProvide mechanical /artificial

respiration.respiration.

Always monitor the affected area.Always monitor the affected area.

??


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During Gas ExposureDuring Gas Exposure

DONOTDONOT

Crowd around the victim.Crowd around the victim.

Leave victim alone.Leave victim alone.

Allow him to sleep.Allow him to sleep.

Give anything to eat or drink.Give anything to eat or drink.

Allow victim to run.Allow victim to run.

Ignore any symptoms.Ignore any symptoms.


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Safe Limit ofCarbonSafe Limit ofCarbon

Monoxide in AirMonoxide in Air

Threshold limiting value (TLV) forThreshold limiting value (TLV) for

8 work hours day :8 work hours day :50ppm or 0.0550ppm or 0.05 mgmsmgms//ltlt

Short term exposure limit (STEL)Short term exposure limit (STEL)

for 15 minutes TLV exposure :for 15 minutes TLV exposure :

400ppm or 0.456400ppm or 0.456 mgmsmgms// ltlt


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Detection of Gas LeakageDetection of Gas Leakage

Watch wind direction.Watch wind direction.

Monitor near by areas with portable COMonitor near by areas with portable COmonitormonitor Evacuate people in the direction of windEvacuate people in the direction of wind Wear breathing apparatus if CO conc. is high.Wear breathing apparatus if CO conc. is high.

Check Valves, flanges & throttles .Check Valves, flanges & throttles . Watch for visible gas leakage spot on gas lineWatch for visible gas leakage spot on gas line Carefully listen if any hissing sound of gasCarefully listen if any hissing sound of gas

leakage is present.leakage is present.

Call Gas SafetyCall Gas Safety Watch for water droppings.Watch for water droppings. Watch for discoloration of down belowWatch for discoloration of down below

structures and pipeline.structures and pipeline.


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Action to be taken During gasAction to be taken During gasLeakagesLeakages

Approach from the direction of wind.Approach from the direction of wind. Breathing apparatus is must.Breathing apparatus is must. Cordon Off the Entire area.Cordon Off the Entire area. Monitor gas concentration in the area.Monitor gas concentration in the area. Identify the source of leakageIdentify the source of leakage

Asses the direction of gas flow.Asses the direction of gas flow.

Contd.Contd.


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People wearing Gas mask should bePeople wearing Gas mask should beallowed to work at the affected area.allowed to work at the affected area.

Contact gas dispatcher to reduce gasContact gas dispatcher to reduce gasnetwork pressure (ifnetwork pressure (if reqdreqd).).

Keep Ready:Keep Ready: Sufficient Nos. of BreathingSufficient Nos. of Breathing

apparatus.apparatus.

CO. MonitorInstruments.CO. MonitorInstruments. Gas leakage arresting kit.Gas leakage arresting kit.

Emergency Vehicle.Emergency Vehicle.



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Case StudyCase Study --11

Blast Furnace 4Blast Furnace 4Dust Catcher PlatformDust Catcher Platform

66thth March 2007, 11.35 AMMarch 2007, 11.35 AM

BhilaiBhilai Steel PlantSteel Plant


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Furnace cut off valve

operating panelDust Catcherbleeder opr panel

Dust valve dia

600 mm

Dust

Catcher

VictimVictim

Dust valvewinch

Housing

Remote opening

switch

Furnace Cutoff valvewinch

Sec. Dustvalvewinch

D/Cbleederwinch

WinchRoom

Approach

Approach

ROAD

Affected

Persons

BF- 4 Area

+6.4 mt level

+11.2 mt level

Stove Area

LayoutLayout


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ObservationsObservations Due to the absence of any level sensor,Due to the absence of any level sensor,

valve closing is totally dependent onvalve closing is totally dependent onthe skill & experience of the operator.the skill & experience of the operator.

Slight delay in closing can cause heavySlight delay in closing can cause heavyleakage of BF gas.leakage of BF gas.

Dust valve motor was found out ofDust valve motor was found out offoundation & all coupling bolts exceptfoundation & all coupling bolts except

one were broken.one were broken. Slight delay in reducing the Blast toSlight delay in reducing the Blast to

0.250.25--0.3 kg/cm0.3 kg/cm22from 1kg/cmfrom 1kg/cm22

Contd.Contd.


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Only route to the winch room was throughOnly route to the winch room was throughdust catcher platform.dust catcher platform.

No gas detection & alarm system wasNo gas detection & alarm system was

installed.installed.

Insufficient escape routes.Insufficient escape routes.

No system of checking of dust valvesNo system of checking of dust valves

before operation.before operation.



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RecommendationsRecommendations

Dust catcher winch drive should beDust catcher winch drive should beshifted to safer platform to preventshifted to safer platform to prevent

people from any gas exposure.people from any gas exposure. A joint inspection of dust valve winchA joint inspection of dust valve winch

drive should be done by Opr, Elect &drive should be done by Opr, Elect &Mech before every dust valveMech before every dust valve

operation.operation. Automatic CO gas monitor with alarmAutomatic CO gas monitor with alarm

system should be installed on the dustsystem should be installed on the dust

valve platformvalve platform.. Contd.Contd.


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Before entering into gas proneBefore entering into gas pronearea it should be ensured thatarea it should be ensured thatgas conc. is within the safegas conc. is within the safe

limits.limits. One Gas Mask to kept at FFCROne Gas Mask to kept at FFCR

of each Blast Furnace.of each Blast Furnace.

Provision of wind indicator mayProvision of wind indicator maybe madebe made



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Case Study - 2


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BRIEFINGBRIEFING

BlastBlast FceFce gas line of BFgas line of BF--6 stove6 stoveno.19 was isolated.no.19 was isolated.

Steaming carried out for one hour.Steaming carried out for one hour.

S

ample taken and found 100% gasS

ample taken and found 100% gasin it.in it.


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LAYOUTLAYOUT

Dia1200mm Blast Furnace gas line

Stove-18

Stove-19

Stove-20

Steam line

Isolated


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OBSERVATIONSOBSERVATIONS

Sample was showing normal inSample was showing normal inpresence of inert media.presence of inert media.

Sample showed 100% gas on closingSample showed 100% gas on closing

inert media.inert media.

FINDINGSFINDINGS

Gas was entering to isolated gasGas was entering to isolated gas

line through connected steam line.line through connected steam line.

Branch steam line valves were notBranch steam line valves were notdisconnected / blanked.disconnected / blanked.


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RECOMMENDATIONSRECOMMENDATIONS

Purging connection not in use shouldPurging connection not in use shouldbe isolated / disconnected.be isolated / disconnected.

Purging media to be disconnectedPurging media to be disconnectedafter purging.after purging.

Sample should be taken afterSample should be taken afterdisconnecting the purging point.disconnecting the purging point.


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HHazards can be controlled, ifazards can be controlled, if

we follow the safe workwe follow the safe work

procedure. one error canprocedure. one error cancause extensive damage to thecause extensive damage to the

plant & may toll human lives.plant & may toll human lives.

Gas is a good servant,Gas is a good servant,

But a bad master.But a bad master.


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TTHANKHANK YYOUOU

gs iron making21.09.10 ocean -

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