vucinic bojan electric arc versus induction furnace...

DANIELI / SINCE 1914PASSION TO INNOVATEAND PERFORMIN THE METALS INDUSTRY

VUCINIC BOJANSENIOR PROCESS ENGINEERDANIELI CENTROMET

2017 SEAISICONFERENCEAND EXHIBITION22-25 MAYSENTOSA, SINGAPORE

ELECTRIC ARC VERSUS INDUCTION FURNACEIN STEELMAKING PROCESS

INDEXINDUCTION VERSUSELECTRIC ARC FURNACEIN STEELMAKING PROCESS

1. CRUDE STEEL PRODUCTION_ STEELMAKING TRENDS

2. COMPARISON OF ELECTRIC ARC VERSUS INDUCTION FURNACE

3. PROCESS ANDPRODUCTION FLEXIBILITY

4. EAF_ PROCESS CONTROL IMPROVEMENTS

5. CONCLUSIONS

^

CRUDE STEEL PRODUCTION STEELMAKING TRENDS

INDUCTION VERSUSELECTRIC ARC FURNACEIN STEELMAKING PROCESS





5. CONCLUSIONS

OVERVIEWSTEELMAKING PROCESSES

CRUDE STEEL PRODUCTION_ STEELMAKING TRENDS

> Electrical (EAF, Induction furnace)

> Integrated (BF-BOF mainly)

> DRI plants2016

1,6 billion t crude steel

~1,2 billiont hot metal

520 Mt ferrousscrap

75 Mt direct

reducediron

OVERVIEWSTEELMAKING PROCESS ROUTE


> BOF as dominated primary steelmaking unit

> Expansion of EAF process

> OHS – negligible participation

EAF 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014

European Union (28) 38,4% 40,2% 40,3% 41,6% 43,9% 41,1% 42,6% 41,8% 39,8% 38,9%

Other Europe 70,9% 72,4% 74,5% 72,1% 68,7% 70,3% 72,6% 74,0% 71,7% 70,1%

C.I.S. 16,3% 18,3% 20,6% 23,2% 22,4% 22,1% 22,0% 24,8% 23,6% 25,9%

North America 56,0% 57,8% 58,6% 57,6% 61,4% 60,6% 60,5% 59,6% 61,0% 61,7%

South America 36,1% 38,4% 37,2% 36,0% 37,4% 34,4% 34,9% 34,8% 35,9% 33,8%

Africa 58,3% 59,0% 63,4% 64,5% 65,0% 66,1% 67,6% 67,4% 67,2% 68,9%

Middle East 83,8% 85,7% 88,3% 88,1% 88,8% 89,3% 90,1% 91,4% 92,5% 90.9%

Asia 23,7% 22,5% 23,0% 23,1% 19,8% 20,7% 20,5% 19,2% 16,3% 15,9%

Oceania 19,2% 19,2% 20,0% 20,2% 19,2% 17,9% 20,5% 24,2% 23,9% 23,7%

China 12% 10% 12% 12% 10% 10% 10% 9% 7% 6%

OVERVIEWEAF EXPANSION


> e.g. China flexibility, high quality grades, scrap availability

> EuropeCO2 footprint + high quality grades

> USAshall gas availability + flexibility

Mr. Mario Longhi(CEO of the USS Corporation):“While the blast furnace is expensive to turn off and on and to maintain and depends on iron ore and coal prices, steel in an EAF is made by melting shredded scrap metal in a process that can be started and stopped at will without excessive costs” – Gulf News

Source: World Steel Association

> Induction furnace:

> as primary steelmaking unit (India, mainly)

> as additional equipment for alloy meltingEAF

BO

F

Indu

ctio

nFu

rnac

e

22%

44%

34%

India

^

COMPARISON OFELECTRIC ARC VERSUS INDUCTION FURNACE






5. CONCLUSIONS

STEELMAKING CHEMISTRY CONTROLCOMPARISON OF ELECTRIC ARC VERSUS INDUCTION FURNACE

Refining partof process Very good Limited / low

Oxygen blowingapplication Yes (different type) No

Slag buildersapplication

Yes (different type) Limited / low

Raw material Different Based on requiredchemistry

Phosphorouscontent control

Process control(slag builders +oxygen application)

Scrap cleanless

Sulphur control Limited (oxygenapplication)

Limited – there is no sulphur removal

Carbon control Process control Proper material selection

Nitrogen control Raw material +process control

Could be lower thanduring EAF process

BEST AVAILABLETECHNOLOGIES

> Raw material availability,quality pointand price – forecast

> Product mix (steel quality)

> Operational costs

> Required labour profile, availability and costs

> Available area / footprint

> Future melt shop expansion

> Environmental regulationsand cost

> Investmentand breakeven analysis

STEELMAKING CHEMISTRY CONTROLCOMPARISON OF ELECTRIC ARC VERSUS INDUCTION FURNACE

Phosphorouscontentafter primarysteelmakingprocess

Carbon and phosphorouscontent aftertapping frominduction furnace

0,150,160,170,180,190,200,210,220,230,24

Car

bon

cont

ent,

%0 20 40 60 80

0,00

0,05

Pho

shor

ous

cont

ent,

%

0 20 40 60 80

0,01

0,02

0,03

0,04

Heat in production sequence

0%

10%

30%

60%

50%

40%

20%

70%

80%

90%

100%

Freq

uenc

y%

Phosphorous content / range %

< 0,01 0,011-0,015

0,0151-0,020

0,021-0,025

0,026-0,030

0,031-0,035

>0,035

EAF – scrap based process / high quality gradeEAF – scrap based process / rebar gradeInduction furnace melt shop – 1 rebar gradesInduction furnace melt shop – 2 rebar gradesBEST AVAILABLE

TECHNOLOGIES

> Raw material availability,quality pointand price – forecast

> Product mix (steel quality)

> Operational costs

> Required labour profile, availability and costs

> Available area / footprint

> Future melt shop expansion

> Environmental regulationsand cost

> Investmentand breakeven analysis

CHARACTERISTICSCOMPARISON OF ELECTRIC ARC VERSUS INDUCTION FURNACE

Melting vessel Low d / h ratio

Crucible wall thickness Low

Slag temperature Low

Bath motion Powerful

TWO MAIN CHALLENGESFOR INDUCTION FURNACE

> Raw material availability

> Electrical energy consumption

0%

<300 kWh/t

10%

30%

60%

50%

40%

20%

Distribution

301-350 kWh/t

351-400 kWh/t

401-450 kWh/t

451-500 kWh/t

501-550 kWh/t

551-600kWh/t

601-650 kWh/t

>650 Wh/t

EAF – Cont. scrap charging Induction Furnace EAF Bucket charging process

Electrical energy consumption

ELECTRICAL ENERGY CONSUMPTIONCOMPARISON OF ELECTRIC ARC VERSUS INDUCTION FURNACE

REDUCTION OF ELECTRIC ENERGY CONSUMPTIONFOR INDUCTION FURNACE

> Initial scrap charging by bucket

> Power on controlduring de-slagging operation

> Ensuring full crucible before tapping

> Minimum holding time

> Proper scheduling of furnace

> Scrap quality

C

A

B

C

A

B

C

A

B

Power on start Power on finished

4:19 6:43 9:07 11:31 13:55

5055505045554045

Time scale

0 50 100 150 200Power on duration, minutes

145

165

130

130

130

140

185

180

180

Three induction furnaces in production cycle

Three induction furnaces in production cycle (power on time)

ELECTRICAL ENERGY CONSUMPTIONCOMPARISON OF ELECTRIC ARC VERSUS INDUCTION FURNACE

ELECTRICAL ENERGY CONSUMPTIONDURING IF PROCESSINFLUENCED MAINLY BY

> Furnace practice

> Melt shop production schedule

> Type of raw material

> Material availability

> Process requirements

0%

60%

Hot induction furnacewith hell and cover

10%

20%

30%

50%

40%

Cold Induction Furnace Cold induction furnacewithout cover

Total energy losses (supplied energy – energy transfered to the steel)

Energy accumulated - refractory

Energy losses due to radiation

IMPACT ON ELECTRICAL NETWORKCOMPARISON OF ELECTRIC ARC VERSUS INDUCTION FURNACE

General statement Stronger Less

Improvements to reduce flickers Continuous —

IMPROVEMENTSTO REDUCE FLICKERS

> Flat bath conditions

> Type of material – impact on flicker formation

> Biggest impact:heavy melted scrap withbucket charging process

> Reduce flicker:application of light scrap

> AC versus DC furnace

Power system design is led by the minimization of the Flicker

1%95

redpcc

EAF

KSsc

KstSscPst

AC

DC

Scrap heavy

Scrap light

Flath bath

Scrap heavy

Scrap light

Flath bath

0% 10% 20% 30% 40% 50% 60% 70% 80%

PST

IMPACT ON ELECTRICAL NETWORKCOMPARISON OF ELECTRIC ARC VERSUS INDUCTION FURNACE

> Kst - factor is a function of the type of melting operation

1.conventional (batch) scrap melting AC – heavy scrap2.conventional (batch) scrap melting AC – light scrap3.conventional (batch) scrap melting DC – heavy scrap4.conventional (batch) scrap melting DC – light scrap5.continuous preheated scrap melting AC – light scrap6.continuous preheated scrap melting DC – light scrap

-30

1,0

2,0

3,0

4,0

6,0

7,0

5,0

PS

T95

35 40 45 50 55 60 65 70Pmax

DC

AC

Flicker comparison AC vs. DC

0

1

2

3

4

5

6

0 100

MAN POWERCOMPARISON OF ELECTRIC ARC VERSUS INDUCTION FURNACE

Number ofoperators Less Higher

Automatic sampler Manual (safetyissue…splashing)

Automatic scrapbucket charging

Continuous materialcharging

Automatic EBT filling, etc…

Operator skills Higher Less

With automatic furnace

Operator = Supervisor

ENVIRONMENTAL IMPACTCOMPARISON OF ELECTRIC ARC VERSUS INDUCTION FURNACE

Fume extractionsystem Advanced Not completely successful

> The fume extraction system from IF has always been an issue since the fume tends to escape from the open top. No hood design till today has been totally successful.

With the pollution norms becoming more stringent every passing day, this is going to be a major issue in the future

> The fume extraction system of EAF is full proof

ENVIRONMENTAL IMPACTTYPICAL EAF-FTP SCHEME

COMPARISON OF ELECTRIC ARC VERSUS INDUCTION FURNACE

^

PROCESS ANDPRODUCTION FLEXIBILITY






5. CONCLUSIONS

> Possibility to produce different steel grades

> To be present on the market with high quality product with competitive price:

> Low running costs (safety, melt shop efficiency, optimized overall energy consumption, optimized man power cost)

> High productivity

> Possibility to use different charging mix

CHARGE MATERIAL FLEXIBILITYPROCESS ANDPRODUCTION FLEXIBILITY

Electrical energy and oxygen consumptionfor different charge mixes during EAF process

1. 20% scrap + 80% HBI (Bucket + Continious)2. 50% scrap + 50% hot DRI3. 70% scrap + 30% HBI (Bucket + Continious)4. Scrap / Continuous shredded scrap charging5. 100% hot DRI (continious charging)6. Scrap / bucket7. Scrap + hot metal (30-50% hot metal)

1. Scrap + hot metal (30-50% hot metal)2. Scrap / Continuous shredded scrap charging3. Scrap / bucket process4. 100% hot DRI (continious charging)5. 70% scrap + 30% HBI (Bucket + Continious)6. 50% scrap + 50% hot DRI7. 20% scrap + 80% HBI (Bucket + Continious)

01

100

200

300

400

500

600 Electrical energyconsumption, kWh/tls

2 3 4 5 6 7

Type of charge mix material

01

20

25

30

35

40

Oxygenconsumption, Nm3/h

2 3 4 5 6 7

15

10

5


> Different type of scrapby keeping good qualityfor downstream process

> Continuous scrapcharging system

> Scrap preheating

> Continuous chargingof shredded scrap

> HBI; DRI or pig iron

> Hot metal (0-90%)

Electrical energy and oxygen consumptionfor different charge mixes during EAF process

CHARGE MATERIAL FLEXIBILITYPROCESS ANDPRODUCTION FLEXIBILITY

00

250

350

Electrical energy consumption, kWh/tls

20 30 40 50 60 70

150

50


1035

95

115

75

55

135

Productivity, t/hOxygen consumption, Nm3/tls

t/h – 6,1m

t/h – 5,8m

Electrical energy consumption, kWh/tls

Oxygen consumption, Nm3/tls

“While the technology is key to the mini-mill concept, the concept of the mini-mills is more closely tied to a business strategy and management philosophy then it is to technology”

Mini-mills revisited, MetalBulletinMagazin, March 2017

PRODUCTION FLEXIBILITYPROCESS ANDPRODUCTION FLEXIBILITY

QUALITY CONTROLPROCESS ANDPRODUCTION FLEXIBILITY

ELECTRIC ARC FURNACE

> Different charge mix

> Proper slag from basicity and Fe-oxides content point of view

> Temperature control

INDUCTION FURNACEA proper scrap selection from:

> Carbon,

> Phosphorous;

> Residual elements point of view

Nitrogen distribution for scrap based EAF process

Nitrogen content for different scrap during EAF vs. pig iron ratio

Copper content for different charge mixes during EAF process

0%

80%

0Cu content, %

10%

30%

20%

40%

50%

70%

60%

0,002 0,004 0,006 0,008 0,01

EAF process with high hot metal consumption (80-85%)

EAF process with DRI (hot and cold)

0,08 0,11 0,14 0,17 0,2 0,23 0,26 0,29

Scrap based process

0%<30 30-

4040-50

50-60

60-70

70-80

80-90

90-100

>100

5%

10%

15%

25%

20%

30%

35%

Nitrogen content before tapping, ppm

Averagenitrogencontent beforetapping, ppm

420 0-10% 10-20% 20-30%

44

46

48

50

52

54

^

EAF_ PROCESS CONTROL IMPROVEMENTS






5. CONCLUSIONS

EAF EVOLUTIONEAF_ PROCESS CONTROL IMPROVEMENTS

IN THE PAST> Considered for scrap

based process only

THEN, CONTINUOUSPROCESS AND EQUIPMENT IMPROVEMENT> Process control> Power off reduction> Energy saving and optimization

> Chemical package optimization> Electrode regulation> Slag foaming practice control> Yield improvement

> Different charging practice> Bucket process> Continuous charging> Combined charging practice

> Productivity – same as BOF> Different charge mix

> Scrap > Hot metal> DRI/HBI> Pig Iron

1970 1976 1980 1985 1990 1996 2000 2006 2050

250

350

450

550

650

years

120

150

180

90

60

30

0

Ultra High Power EAF

CO post-combustion

1000 kVA/t 1500 kVA/t

Foaming slag

Secondary metallurgy

Oxygen-gas burners

Sidewall and roofwater cooled panels

Intensive using of oxygen and carbon

Tap-

to-t

apti

me

min

Ele

ctro

deco

nsum

ptio

nkg

/t

Ele

ctri

cale

nerg

yco

nsum

ptio

nkW

h/t

0

2

4

6



based process only






V

Set-point C alculation

Speed

Position

Z-Error

Initial C ontact Logic

Z-Measure

C ontrol loop insertion logic

I

Regulator

+

-∑÷

I Input

V Input



based process only






^

CONCLUSIONS






5. CONCLUSIONS

CONCLUSIONS

> Required product mix > Scrap availability> Additional material availability> Safety policy> Environmental policy> Required productivity > Quality of available electrical network

EAF FLEXIBILITY> Usage of different materials > High quality grades production capabilities> Different charging practices> Strong environmental control> Reduced electrical energy consumption > Fully advanced process control

DANIELI / SINCE 1914PASSION TO INNOVATEAND PERFORMIN THE METALS INDUSTRY

VUCINIC BOJANSENIOR PROCESS ENGINEERDANIELI CENTROMET

2017 SEAISICONFERENCEAND EXHIBITION22-25 MAYSENTOSA, SINGAPORE

ELECTRIC ARC VERSUS INDUCTION FURNACEIN STEELMAKING PROCESS

vucinic bojan electric arc versus induction furnace...

Documents