BLAST FURNACE SIZING CONSIDERATIONS - for Incredible India Danieli Corus Jan 30, 2016 at Ranchi,India 1
Contents Blast furnace sizing, What is the optimum profile? What is the optimum size? Blast furnace operation, What is the specific challenge in India? Why is PCI and oxygen important (BF Plus)? What is the future? What demands does the future impose on the furnace? DC s Lining and cooling design DC s glimpse of big furnaces
DC Furnace profile selection > Aim is to choose the best dimensions considering site specific constraints, > High slag volume > Quality of raw materials > Production plans > Coal injection rate > Dimensions effect each other > One dimension cannot be considered without checking its effect on the others > An iterative process to determine best balance based on experience Consideration Productivity Flooding Hearth capacity Burden distribution Layer thickness Burden descent and gas flow Recovery Main dimensional constraints Working volume Hearth diameter Hearth diameter and height Throat diameter Throat diameter, belly diameter Belly and stack angles, Belly diameter Tuyere to taphole height
Hearth volume Required to give buffer for liquid drainage (high slag volumes) Must be balanced with tuyere to taphole height for preventing loss of connection and for easier recovery DC prefers to maintain higher value
Throat diameter Considering burden distribution, layer thickness, chute length and gas flow Limited size for accurate burden distribution and spreading of fines, especially with lower quality raw materials
Why not ultra-large? Ultra-large furnaces (>4,800 cu.m useful volume) become fatter at the belly > Throat diameter limited due to chute charging and good burden distribution > Extra height is not utilized by chemical reactions and give no benefits (only extra pressure drop) Penalties for ultra-large furnaces > Higher fuel rate > Lower productivities: higher pressure drop (relatively small throat) > More difficult operations leading to upsets (scab formation, channeling) > More difficult recovery from chills Penalties are magnified due to India s challenges, > Lower quality raw materials > Fluctuations in raw materials > Low cost operation (high PCI)
Ultra-large BF and Raceway penetration Raceways depth limited due to coke degradation and pressure drop Ultra-Large furnaces have a relatively higher inactive zone for gas due to fatter belly Burden/gas distribution more critical and difficult At low production (<1.6 t/m3iv) and gas flows inactive zone becomes larger More difficult to distribute small gas flow in ultra-large cross sections Leads to less stable operation Channeling and scabs Higher fluctuations in heat loads Penalty in efficiency and production Inactive zone Active, raceway zone
Ultra-large BF and Burden distribution Fines do not spread across fatter belly of ultra-large furnace, but descend vertically Makes gas flow more difficult to control Fat belly's lead to thinner coke slits, limiting PCI and difficulties with burden descent and flooding Fines descend vertically Extreme throat diameters make fines distribution more difficult due to very high volume required in outer rings close to each other Leads to less stable operation Channeling and scabs Higher fluctuations in heat loads Penalty in efficiency and production
Heat and fluctuating heat loads > Unstable gas flows Upper Stack Middle Stack Lower Stack Belly Bosh
Operations benchmark BLAST FURNACE NAME Inner Volume (m³) Hearth Diameter (m) Daily Production (THM/d) Productivity (t/m³iv.d) Slag volume (kg/thm) PCI rate (kg/thm) Availability % Annual Production MTPA NSC Oita No. 1 5,775 15.6 13,500 2.34 308 125 - NSC Oita No. 2 5,775 15.6 13,500 2.34 284 140 97.1 4.8 POSCO Pohang No. 4 5,500 15.6 13,750 2.50 305 180 - NSC Kimitsu No. 4 5,555 15.5 12,770 2.30 300 36 97.0 4.5 JFE Fukuyama No. 5 5,500 15.6 11,800 2.15 269 138 - POSCO Gwangyang No. 4 5,500 15.6 13,750 2.50 305 170 - NSC Nagoya No. 1 5,443 15.2 12,000 2.20 294 126 - Kobe Kakogawa No. 2 5,400 15.3 11,000 2.04 - Sumitomo Kashima No. 3 5,370 15.0 11,600 2.16 287 98 98.3 4.2 Sumitomo Kashima No. 1 5,370 15.0 11,500 2.14 - Hyundai Steel Nos. 1 3 5,250 14.8 11,650 2.22 180 - JFE Chiba No. 6 5,153 15.0 11,500 2.23 328 96 97.5 4.1 JFE Mizushima No. 3 5,055 14.7 11,200 2.22 318 - JFE Mizushima No. 4 5,005 14.6 11,200 2.24 318 120 - JFE Keihin No. 2 5,000 14.8 11,500 2.30 - JFE Fukuyama No. 4 5,000 14.6 10,000 2.00 276 167 - Shagang No. 1 5,860 15.3 12,670 2.16 280 190 - ThyssenKrupp Schwelgern No. 2 5,484 14.9 13,000 2.37 274 156 95.3 4.5 Severstal Cherepovets No. 5 5,552 15.1 12,500 2.25 272 140 98.0 4.5 Shougang Caofeidian Nos. 1 2 5,576 15.5 12,650 2.27 300 170 - - TATA IJmuiden 7 4,450 13.7 12,500 2.81 240 270 98.5 4.5 Normal achieved 2 to 2.4 t/m3iv/d, record, 2.5. All with very good raw materials.
Challenges in India High Al 2 O 3 in ore Negative for sinter quality High fines and degradation in shaft High slag rate Fluctuations in raw material quality Expensive coking coals High demands on furnace lining result of all above reasons for inconsistent gas flow What can you do? 1. Optimize furnace size and profile 2. Use most robust lining/cooling system 3. Increase coal injection using local coal 4. Enhance operational practice
Blast Furnace Design Criteria Availability > 98% Campaign Life > 20 Years Stable and Optimal Profile during entire Campaign Lowest heat loss - Low Cost Hot Metal 12
HOOGOVENS Benchmark (Current ly Tata Steel Ijmuiden) BF 6 BF 7 Unit Inner Volume 2,678 4,450 m 3 Working Volume 2,328 3,775 m 3 Avg. Production 8,000 11,000 THM/d Avg. PCI rate 240 230 kg/thm O2 enrichment 18 14 % Productivity 3.4 2.9 THM/WVm 3 Campaign Life >25 >25 Yrs 13
Lining Attack Mechanism 14
CAMPAIGN LIFE > 20 yrs More than 120 nos reference globally COOLING & LINING SYSTEM - Robustly designed to handle high & Fluctuating heat load Campaign Life > 20 years 15 15
Hoogovens Bosh/ Belly/ Stack Design > Machined Copper Plate Coolers and Graphite: No mortar no week joint > Intrinsic Erosion Resistance by stable accretion layors > Low shell temperature Field weld Shop weld in out 16
Hoogovens - Blast Furnace Proper Tata Steel BF7, Netherlands > 25 years life 17
Hoogovens Bosh & Stack IJmuiden BF6 Status 16 Years On-Going Bosh and Stack Campaign since 1986 30 years 18
Hoogovens IJmuiden BF7 Inner Volume 4450 m 3 Hearth Diameter 13.8 m Annual Production 4.0 MT Commissioning 1992
AMK Ukraine BF 2 20
NMDC Nagarnar BF1 Inner Volume 4506 m 3 Hearth Diameter 14.2 m Annual Production 4.0 MT Commissioning 2015
TISCO Taiyuan BF4 Inner Volume 4961 m 3 Hearth Diameter 14.2 m Annual Production 4.5 MT Commissioning 2014
POSCO Gwangyang BF1 Inner Volume 6095 m 3 Hearth Diameter 16.1 m Annual Production 5.6 MT Commissioning 2013
Score Card, Blast Furnace Ironmaking 124 Blast Furnace Projects 220 Hot Blast Stoves 65 Pulverized Coal Injection Systems 131 Blast Furnace Gas Cleaning Systems 34 Slag Granulation Systems 157 Technical & Operational Assistance Projects 24
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