LKAB Blast Furnace Research Areas 2004

1
Blast Furnace Seminar Oulu March 30, 2004
EFFECT OF BLAST MOISTURE - EBF Testing Lawrence
Hooey Johan Riesbeck (Luleå University of
Technology)
2

Contents

• Background
• Experimental
• Results
• Discussion
• Preliminary conclusions

3
Organisation
Background
Furnace A
Furnace B
Burden
Pellets/sinter/lump
Pellets/sinter
Injection
Oil
Natural gas
Injection rate kg/thm
59
26
Oxygen content of blast
22.1
21.5
o
Blast temperature
C
1189
1050
3
Moisture content of blast g/nm
24
15
o
Flame temperature
C
2160
2215
Top gas H
Content
3.9
2.6
2
o
Top gas temperature
C
128
gt200
Total fuel rate kg/thm
454
515
4
Organisation
Background
Rules of thumb
1 g/nm3 moisture ? 0.5 to 1 kg coke
Rule developed under low blast temperature
conditions. Does this hold under conditions
tested in the EBF?
5
Organisation
Background
Power Plant
Blast furnace
Blast heating
Enrichment
6
Organisation
Background/ first test
16 g/nm3
35 g/nm3
Oil injection 44 kg/thm Low oxygen
enrichment Results Slightly improved descent no
significant increase in fuel rate
7
Organisation
Experimental
BF Burden Slag rate 180 - 200
kg/thm KPBA Pellets 1400 kg/thm Limestone,
quartzite, BF-slag and LD slag additives
8
Organisation
Experimental
Constant conditions Blast volume (dry) 1865
nm3/h Oxygen enrichment none Blast
temperature 1200 oC Propane injection 40
kg/h blast temp. measured at heater
output temp at tuyeres lies circa 150oC lower
9
Organisation
Experimental
Test Conditions
Period 1a
Period 1b
Period 2
Period 3
Blast moisture
16
16
35
52
3
g/nm
Flame temperature
2220
2220
2110
2000
o
C
Duration
70
33
42
78
hours
H2 in bosh gas 5.3 5.3 7.2
9.0
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Organisation
Results
16 g
35 g
16 g
52 g
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Organisation
Results
52 g
35 g
16 g
16 g
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Organisation
Summary of Results
1a 16g
1b 16g
Ave 1
2 35g
3 52g
Coke rate kg/thm
462
494
478
473
515
Propane rate kg/thm
29
31
30
30
30
o
Hot metal T
C
1433
1441
1437
1446
1370
Hot metal Si
1,8
2,4
2,2
2,0
1,0
Top gas H

2,9
3,0
3,0
3,8
4,3
2
o
Top gas T
C
222
262
242
253
245
TG Heating value
3,0
3,2
3,1
3,3
3,4
3
MJ/nm
DRR Rate kg C/thm
80
89
84
64
91
13
Organisation
Discussion
worse reduction
1st test
Improved reduction
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Organisation
Discussion
Lower shaft probe -3.45 m below stockline 2.55
m above tuyere
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Organisation
Discussion
35 g
16 g
16 g
52 g
16
Organisation
Discussion
What to graph?
17
Organisation
Conclusions
Under conditions tested Lower limit in flame
temperature below c. 2100 oC and/or Upper limit
in moisture between 35 and 52 g/nm3 Little
reductant rate difference 16-35g/nm3 Possible
improved stability...
18
Organisation
Further considerations

• Lower furnace heat balances, DRR, reducibility
  of burden...
• EBF operation compared to commercial furnace
• Effect of materials furnace stability?
• Stove operation under modified conditions?
• Overall energy useage/economics

19
Blast Furnace Seminar Oulu March 30, 2004
Thank you for your attention! Comments,
questions, discussion
20
Organisation
Discussion