Blast Furnace Process18.11.2014 Peter Schmöle1 ThyssenKrupp Steel Europe
The Blast Furnace Process- Requirements on coke
Verfahrenstechnik und Chemieingenieurwesen in Stahli ndustrie und Kokereitechnik
18. November 2014, TU Clausthal
Prof. Dr.-Ing. Peter Schmöle
Head of Competence Centre Metallurgy, ThyssenKrupp Steel Europe
Blast Furnace Process18.11.2014 Peter Schmöle2 ThyssenKrupp Steel Europe
� Introduction
� Roles of coke
� Flooding effects
� Blast furnace performance
The blast furnace process- Requirements on coke
� Conclusion
� The blast furnace process
Blast Furnace Process18.11.2014 Peter Schmöle3 ThyssenKrupp Steel Europe
• Studies of ferrous metallurgy and Dr.-Ing. at the TU Clausthal
• Started the industrial career in1983 with Hoesch Stahl in Dortmund
� Process technique steel making (BOF shop)
� General manager for the hot metal production in the BFworks Phoenix and Westfalenhütte and for the energydivision of the integrated works of Hoesch-Hüttenwerke
• Since 1997 with ThyssenKrupp Steel in Duisburg
� Head of hot metal technology
� Deputy leader hot metal division
� Head of Competence Centre Metallurgy
IntroductionThe speaker
Blast Furnace Process18.11.2014 Peter Schmöle4 ThyssenKrupp Steel Europe
Electric steel28.2%
Oxygen steel71.2%
Scrap31.8%
Blast furnacehot metal
63.7%
Open hearthsteel0.6%
DRI / HBI4.1%
Corex / Finexhot metal
0.4%
1606
1822
IntroductionWorld crude steel production and metallic charge, 2013
Blast Furnace Process18.11.2014 Peter Schmöle5 ThyssenKrupp Steel Europe
IntroductionWorld crude steel and hot metal production
Blast Furnace Process18.11.2014 Peter Schmöle6 ThyssenKrupp Steel Europe
IntroductionConsumption of reducing agents in German blast furnaces
Total: 504.6 kg / t HM in 2013
Coke: 331.6 kg / t HM in 2013
Blast Furnace Process18.11.2014 Peter Schmöle7 ThyssenKrupp Steel Europe
� Introduction
� Roles of coke
� Flooding effects
� Blast furnace performance
The blast furnace process- Requirements on coke
� Conclusion
� The blast furnace process
Blast Furnace Process18.11.2014 Peter Schmöle8 ThyssenKrupp Steel Europe
Raceway gas: 2,200 °°°°CCCC(CO, H2, N2)
Hot blast: 1,200 °°°°CCCC
Liquidhot metaland slag:1,500 °°°°CCCC
Top gas: 120 °°°°CCCC(CO, CO2, H2, H2O, N2)
Ore burden,additions,coke
Pulverized coal
GasOre,coke
The blast furnace processThe blast furnace as a counter current reactor
Blast Furnace Process18.11.2014 Peter Schmöle9 ThyssenKrupp Steel Europe
Ore burden 775,000 kg / h
Coke 175,000 kg / h
Slag 125,000 kg / h
Hot metal 500,000 kg / h
Shaft gas 750,000 m³ (S.T.P.) / h
The blast furnace processThe blast furnace as a counter current reactor
The blast furnace processCharging equipment“Parallel feed”
Rotating chute
Gear box
Feeder spout
Material gate
Lower valves
Upper valves
Top bins
Stack radius in m
Sto
ck li
ne le
vel i
n m
Stack radius in m
Sto
ck li
ne le
vel i
n m
6
Chute position 6Chute angle 33.60°
0 1 2 3 4 5 6
0
- 2.0
- 4.0
- 6.0
- 8.0
0 1 2 3 4 5 6
56
Chute position 5Chute angle 44.70°
0
- 2.0
- 4.0
- 6.0
- 8.0
546
Chute position 4Chute angle 40.80°
0
- 2.0
- 4.0
- 6.0
- 8.0
0 1 2 3 4 5 6
0 1 2 3 4 5 6
0
- 2.0
- 4.0
- 6.0
- 8.0
5436
Chute position 3Chute angle 38.90°
0 1 2 3 4 5 6
54326
Chute position 2Chute angle 36.90°
0
- 2.0
- 4.0
- 6.0
- 8.0 Final burdendistribution
0
- 2.0
- 4.0
- 6.0
- 8.0
0 1 2 3 4 5 6
The blast furnace processExample forcharging sequenceof burden and coke
Sto
ck le
vel
[ m ]
Radius [ m ]
The blast furnace processCoke and ore burden distribution
Coke
Ore burden
1 2 30 4 5
0.6
0.4
0.2
0
Burden
Coke
Radius in m
1.0
0.8
Rat
io o
f bur
den
and
coke
0
5
10
15
20
25
30
Dep
th in
m
024 2 4
Radius in m
1.0000
0.4064
The blast furnace processInner state of blast furnace and radial burden distribution
KoksKoks
Koks
4�m3�m2�m
The blast furnace processHe tracing trials with the BF tuyere probe
Blast Furnace Process18.11.2014 Peter Schmöle16 ThyssenKrupp Steel Europe
� Introduction
� Roles of coke
� Flooding effects
� Blast furnace performance
The blast furnace process- Requirements on coke
� Conclusion
� The blast furnace process
Blast Furnace Process18.11.2014 Peter Schmöle17
Chemical challenges
� Energy input
� Generation of reducing gases
� Regeneration of CO 2 (Boudouard - Reaction)
� Carburization of the hot metal
Physical challenges
� Gas permeability and distribution in the BF shaft
� Support of the burden column
� Vertical and horizontal drainage for liquid products
Roles of cokeChemical and physical challenges
Blast Furnace Process18.11.2014 Peter Schmöle18
Roles of cokeDifferent challenges - different coke qualities
Small coke
� Mixed in ore burden
� High reactivity: Consumption in the upper BF
Layer coke
� Sufficient I 40, CSR, size and size distribution
� Low reactivity: Permeability and drainage
Centre or “hearth” coke
� High I 40, CSR and voidage
� Low reactivity: Permeability and drainage
I40, I10
CSR / CRI
All physical coke quality parameters and their interactions are tobe discussed regarding the impacts on the mass and gas flows
Medium grain size,grain structure,grain size distribution
Roles of cokeQuality parameters of coke
Blast Furnace Process18.11.2014 Peter Schmöle20
I40, I10
CSR / CRI
Voidage high small
Gas permeability high low
Drainage high low
Grain size distribution
Grain size distribution
Roles of cokeQuality parameters of coke
Blast Furnace Process18.11.2014 Peter Schmöle21
I40, I10
CSR / CRI
Voidage small
Gas permeability low
Drainage low
Gas permeability
Grain size distribution
Liquid products
Gas permeability
Grain size distribution
Grain size distribution
Roles of cokeBad size distribution
Blast Furnace Process18.11.2014 Peter Schmöle22
I40, I10
CSR / CRI
Voidage small
Gas permeability low
Drainage low
Grain size distribution
Gas permeability
Grain size distribution
Liquid products
Gas permeability
Grain size distribution
Roles of cokeGood size distribution, low I 40
Blast Furnace Process18.11.2014 Peter Schmöle23
I40, I10
CSR / CRI
Gas permeability
Grain size distribution
Grain size distribution
Liquid products
Gas permeability
Grain size distribution
Gas permeability high low
Drainage low
Voidage high small
Roles of cokeGood size distribution, high I 40 and low CSR
Blast Furnace Process18.11.2014 Peter Schmöle24
I40, I10
CSR / CRI
Voidage high
Gas permeability high
Drainage high
Gas permeability
Grain size distribution
Grain size distribution
Liquid products
Gas permeability
Grain size distribution
Good coke=
excellent BF performance!
Roles of cokeGood size distribution, high I 40 and high CSR
Blast Furnace Process18.11.2014 Peter Schmöle25
Roles of cokeGeometric lay-out of the blast furnace hearth
Blast Furnace Process18.11.2014 Peter Schmöle26
Volume ofthe sump
Volume of the reservoir for liquids
Roles of cokeGeometric lay-out of the blast furnace hearth
Blast Furnace Process18.11.2014 Peter Schmöle27
Forces on the dead man
� Weight of the total material column
� Upstream gas flowf = (Volume, density, viscosity)
� Friction of the descending burden on the walls
� Support of the material column on the bosh wall
� Lifting of the solid coke in the liquid materialsf = (Height of the liquids in the hearth, coke bed v oidage)
Is the dead man swimming or sitting on the bottom?
Roles of cokeIs the dead man swimming or sitting on the bottom?
Blast Furnace Process18.11.2014 Peter Schmöle28
Swimming dead man
� Hot metal and slag can flow over the free spacebetween bottom and material column directlyto the taphole
Roles of cokeIs the dead man swimming or sitting on the bottom?
Blast Furnace Process18.11.2014 Peter Schmöle29
Sitting dead man
� Hot metal and slag must flow through the cokeof the dead man column to the taphole
� If the voidage of the coke is low, hot metal andslag must flow also around the dead man cokeon the wall of the hearth refractory
Coke free space
Roles of cokeIs the dead man swimming or sitting on the bottom?
Blast Furnace Process18.11.2014 Peter Schmöle30
Taphole
Hearth bottom
Roles of cokeIs the dead man swimming or sitting on the bottom?
Blast Furnace Process18.11.2014 Peter Schmöle31
Roles of cokeWear profile “Elephant foot”
Blast Furnace Process18.11.2014 Peter Schmöle32 ThyssenKrupp Steel Europe
� Introduction
� Roles of coke
� Flooding effects
� Blast furnace performance
The blast furnace process- Requirements on coke
� Conclusion
� The blast furnace process
Blast Furnace Process18.11.2014 Peter Schmöle33
Blast furnace as counter current reactor
Flooding of slag influenced by
� Shaft gas composition, temperature,pressure and the resulting density
� Slag amount, density and viscosity
� Coke specific surface
� Coke bed voidage
Flooding effectsSlag flooding
Blast Furnace Process18.11.2014 Peter Schmöle34 ThyssenKrupp Steel Europe
Counter current flow key figure log (k)
Hol
dup
key
figur
e lo
g (f
)
Hans Beer, Gerhard Heynert: stahl und eisen 84 (1964),No. 22, p. 1353/1365
Based on T. K. Sherwood et al: Flooding Velocities inPacked Columns, MIT, Industrial and Engineering Chemistry, Vol. 30 (1938), p. 765/69
Flooding effectsSlag flooding
Blast Furnace Process18.11.2014 Peter Schmöle35 ThyssenKrupp Steel Europe
Flooding effectsSlag flooding
Case 1 Case 2 %
Gas volume m³ (STP) / t HM 1,300.00 1,300.00 0.00
Gas pressure bar (abs.) 4.00 4.00 0.00
Slag amount kg / t HM 250.00 250.00 0.00
Slag viscosity cP 1,500.00 1,500.00 0.00
Coke specific surface m² / m³ 90.00 90.00 0.00
Coke bed voidage m³ / m³ 0.35 0.35 0.00
Productivity Case 2 / Case 1 % 0.00
Blast Furnace Process18.11.2014 Peter Schmöle36 ThyssenKrupp Steel Europe
Flooding effectsSlag flooding - Gas volume minus 10 %
Case 1 Case 2 %
Gas volume m³ (STP) / t HM 1,300.00 1,170.00 -10.00
Gas pressure bar (abs.) 4.00 4.00 0.00
Slag amount kg / t HM 250.00 250.00 0.00
Slag viscosity cP 1,500.00 1,500.00 0.00
Coke specific surface m² / m³ 90.00 90.00 0.00
Coke bed voidage m³ / m³ 0.35 0.35 0.00
Productivity Case 2 / Case 1 % 7.89
Blast Furnace Process18.11.2014 Peter Schmöle37 ThyssenKrupp Steel Europe
Flooding effectsSlag flooding - Gas pressure plus 10 %
Case 1 Case 2 %
Gas volume m³ (STP) / t HM 1,300.00 1,300.00 0.00
Gas pressure bar (abs.) 4.00 4.40 10.00
Slag amount kg / t HM 250.00 250.00 0.00
Slag viscosity cP 1,500.00 1,500.00 0.00
Coke specific surface m² / m³ 90.00 90.00 0.00
Coke bed voidage m³ / m³ 0.35 0.35 0.00
Productivity Case 2 / Case 1 % 3.49
Blast Furnace Process18.11.2014 Peter Schmöle38 ThyssenKrupp Steel Europe
Flooding effectsSlag flooding - Slag amount minus 10 %
Case 1 Case 2 %
Gas volume m³ (STP) / t HM 1,300.00 1,300.00 0.00
Gas pressure bar (abs.) 4.00 4.00 0.00
Slag amount kg / t HM 250.00 225.00 -10.00
Slag viscosity cP 1,500.00 1,500.00 0.00
Coke specific surface m² / m³ 90.00 90.00 0.00
Coke bed voidage m³ / m³ 0.35 0.35 0.00
Productivity Case 2 / Case 1 % 2.99
Blast Furnace Process18.11.2014 Peter Schmöle39 ThyssenKrupp Steel Europe
Flooding effectsSlag flooding - Slag viscosity minus 10 %
Case 1 Case 2 %
Gas volume m³ (STP) / t HM 1,300.00 1,300.00 0.00
Gas pressure bar (abs.) 4.00 4.00 0.00
Slag amount kg / t HM 250.00 250.00 0.00
Slag viscosity cP 1,500.00 1,350.00 -10.00
Coke specific surface m² / m³ 90.00 90.00 0.00
Coke bed voidage m³ / m³ 0.35 0.35 0.00
Productivity Case 2 / Case 1 % 1.06
Blast Furnace Process18.11.2014 Peter Schmöle40 ThyssenKrupp Steel Europe
Flooding effectsSlag flooding - Coke specific surface minus 10 %
Case 1 Case 2 %
Gas volume m³ (STP) / t HM 1,300.00 1,300.00 0.00
Gas pressure bar (abs.) 4.00 4.00 0.00
Slag amount kg / t HM 250.00 250.00 0.00
Slag viscosity cP 1,500.00 1,500.00 0.00
Coke specific surface m² / m³ 90.00 81.00 -10.00
Coke bed voidage m³ / m³ 0.35 0.35 0.00
Productivity Case 2 / Case 1 % 5.41
Blast Furnace Process18.11.2014 Peter Schmöle41 ThyssenKrupp Steel Europe
Flooding effectsSlag flooding - Coke bed voidage plus 10 %
Case 1 Case 2 %
Gas volume m³ (STP) / t HM 1,300.00 1,300.00 0.00
Gas pressure bar (abs.) 4.00 4.00 0.00
Slag amount kg / t HM 250.00 250.00 0.00
Slag viscosity cP 1,500.00 1,500.00 0.00
Coke specific surface m² / m³ 90.00 90.00 0.00
Coke bed voidage m³ / m³ 0.35 0.39 10.00
Productivity Case 2 / Case 1 % 15.37
Blast Furnace Process18.11.2014 Peter Schmöle42 ThyssenKrupp Steel Europe
Flooding effectsSlag flooding
Change Productivity
% %
Gas volume m³ (STP) / t HM -10.0 7.9
Gas pressure bar (abs.) 10.0 3.5
Slag amount kg / t HM -10.0 3.0
Slag viscosity cP -10.0 1.1
Coke specific surface m² / m³ -10.0 5.4
Coke bed voidage m³ / m³ 10.0 15.4
Blast Furnace Process18.11.2014 Peter Schmöle43 ThyssenKrupp Steel Europe
Flooding effectsConclusion
The blast furnace productivity is influenced by a lot of parameters like
� Gas volume, temperature, composition and pressure
� Slag amount, density and viscosity
� Especially coke quality
� Specific surface (Surface to volume ratio)
� Coke bed voidage
Blast Furnace Process18.11.2014 Peter Schmöle44 ThyssenKrupp Steel Europe
� Introduction
� Roles of coke
� Flooding effects
� Blast furnace performance
The blast furnace process- Requirements on coke
� Conclusion
� The blast furnace process
Blast Furnace Process18.11.2014 Peter Schmöle45 ThyssenKrupp Steel Europe
50
55
60
65
70
75
1995 2000 2005 2010
CS
R [
% ]
Blast furnace performanceCoke quality CSR, ThyssenKrupp Steel Europe
Blast Furnace Process18.11.2014 Peter Schmöle46 ThyssenKrupp Steel Europe
Blast furnace performanceA lot of influences
Blast Furnace Process18.11.2014 Peter Schmöle47 ThyssenKrupp Steel Europe
Blast furnace performanceCSR and BF productivity
Blast Furnace Process18.11.2014 Peter Schmöle48 ThyssenKrupp Steel Europe
0
20
40
60
80
100
1995 2000 2005 2009 2011
Sha
res
of p
rofit
poo
l HR
C [
% ]
Steel
Coking coal
Iron ore
Source:SBB, McKinsey, BCG
Blast furnace performanceShrinking of the steel profit - pool in favour of mining companies
Blast Furnace Process18.11.2014 Peter Schmöle49 ThyssenKrupp Steel Europe
Alternative measures to increase production
Hot metal production [ Mill. t HM / y ]
Cos
ts [
EU
R /
t HM
]
High quality coke:High productivity,low cost level
Hot metal production [ Mill. t HM / y ]
Cos
ts [
EU
R /
t HM
]
Low quality coke:Low productivity,high cost level
Blast furnace performanceCoke consumption, productivity and costs
Blast Furnace Process18.11.2014 Peter Schmöle50 ThyssenKrupp Steel Europe
� Introduction
� Roles of coke
� Flooding effects
� Blast furnace performance
The blast furnace process- Requirements on coke
� Conclusion
� The blast furnace process
Blast Furnace Process18.11.2014 Peter Schmöle51 ThyssenKrupp Steel Europe
2012: Highest hot metal productionin the world, Pohang 4, South KoreaHM production up to 17,000 t / d
1709: First coke based blast furnacein the world, Coalbrookdale, EnglandHM production 2 t / d
ConclusionThe blast furnace operation - 305 years of experience
After 305 years of the coke blast furnace there exists no integratedcoke quality parameter to describe the blast furnace performance!
ConclusionQuality parameters of coke
I40, I10
CSR / CRI
Medium grain size,grain structure,grain size distribution
After 305 years of the coke blast furnace there exists no integratedcoke quality parameter to describe the blast furnace performance!
� Blast furnace performance dependson coke quality
� Postulation of a sufficient coke quality
� Coke production at a cost minimumfrom an integrated point of view
� Need for an integrated coke quality parameter
� Knowledge of the correlations between coking coal blend, coke quality and blast furnace performance
ConclusionCoke quality and blast furnace performance
Blast Furnace Process18.11.2014 Peter Schmöle54 ThyssenKrupp Steel Europe
ConclusionCoke quality and blast furnace performance
Blast Furnace Process18.11.2014 Peter Schmöle55 ThyssenKrupp Steel Europe
ConclusionCoke quality and blast furnace performance
Blast Furnace Process18.11.2014 Peter Schmöle56 ThyssenKrupp Steel Europe
ConclusionCoke quality and blast furnace performance
Blast Furnace Process18.11.2014 Peter Schmöle57 ThyssenKrupp Steel Europe
The Blast Furnace Process- Requirements on coke
Verfahrenstechnik und Chemieingenieurwesen in Stahli ndustrie und Kokereitechnik
18. November 2014, TU Clausthal
Prof. Dr.-Ing. Peter Schmöle
Head of Competence Centre Metallurgy, ThyssenKrupp Steel Europe
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