DESIGN FEATURES OF INDIAN BLAST FURNACES Authors: K R Pal Chaudhuri, GM, MECON S K Verma, Jt GM, MECON S K Bhattacherjee, DGM, MECON A Mondal, AGM, MECON Presented by: S Sengupta, DGM, MECON

Abstract We have attempted to highlight the design features of Indian BFs and bring out the “Technology Status” of existing as well as proposed BF installations both in the large & mini sectors to provide an insight to the operators as well as entrepreneurs. Some of major highlights of the paper includes: Technological features of modern Indian BFs Design features and pre – requisites of modern Ironmaking Important BF design and operating parameters Effect of various parameters on productivity & coke rate International benchmarks The Indian scenario

BF Technology Vs Alternative Ironmaking Processes BF technology for Ironmaking will continue to dominate owing to various reasons: Corex – Finex - Hismelt have only reached commercial stage Investment in alternative processes has elevated business risks Expansion plan under National Steel Policy necessitates adding large production modules through proven BF route Upgradation and modification of existing BFs Impovement in performance of BFs in terms of productivity, cost & environmental friendliness

Major Recent Greenfield & Brownfield Projects of India TATA Steel G & H Blast Furnaces Bhilai Steel Plant, BF No. 7 Bokaro Steel Plant, Blast Furnace No. 2 Rourkela Steel Plant, Blast Furnace No. 5 (commissioned) ISP (IISCO) Steel Plant, Blast Furnace No. 5 (commissioned) Bhilai Steel Plant, Blast Furnace No. 8 (under advanced stage of execution) JSW Steel Limited, Blast Furnace No. 2, 3 & 4 (all commissioned) Bhushan Power, Blast Furnace No. 1 & 2 (under execution) Bhushan Steel Limited, Blast Furnace No. 1 & 2 (under commissioning)

Some Broad Details of Major Modern Indian BFs Technology Supplier Client Major Technical Data Remarks Paul Wurth Tata Steel, BF # H (commissioned - 2008) Useful Volume: 3814 m3 Number of Tuyeres: 34 Hearth Diameter: 13.0 m Production: 2.5 – 2.8 Mtpa (7150 tpd for Bhushan & Tata BF # H has crossed 10,000 tpd) Cooling System: Copper staves SGP - PW INBA system GCP - PW Annular Gap Scrubber TRT - 13.5 MW (design) Top charging - PW BLT system Hot blast system - PW design PCI system - PW design Tata Steel, BF # I (under design & erection) RINL, BF # 3 (under commissioning trials) Bhushan Steel, BF # 2 (under construction) POSCO e & c ISP, New BF (commissioned in Nov 2014) Useful Volume: 4161 m3 Number of Tuyeres: 38 Hearth Diameter: 13.6 m Production: 2.8 Mtpa (8000 tpd) SGP - Rasman Screw type GCP - Bischoff Annular Gap system TRT - 14 MW (Mitsui & Nico) Top charging- PW BLT system Hot blast system - Danieli Corus PCI system – CISRI/NMT/SPCL

Some Broad Details of Major Modern Indian BFs Technology Supplier Client Major Technical Data Remarks Paul Wurth Tata Steel, BF # G (Revamped in 2005) Useful Volume: 2648 m3 Number of Tuyeres: 30 Hearth Diameter: 11.05 Production: 1.8 Mtpa (5150 tpd) Cooling System : Copper staves Double cast house PW BLT system PW GCP (Tangential cyclone + two stage venturi scrubber) Danieli Corus BV RSP, BF # 5 (commissioned in 2013) Useful Volume: 4060 m3 Number of Tuyeres: 36 Hearth Diameter: 13.2 m Production: 2.8 Mtpa (7984 tpd) Cooling System: Copper plate coolers SGP - DC Dewatering Wheel GCP – DC Bischoff system TRT - 14 MW (design) Top charging - PW BLT system Hot blast system - Danieli Corus PCI system - Danieli Corus Siemens VAI JSW Steel (BF # 3 & 4) (BF # 3 commissioned - 2009 BF # 4 under commissioning) JSPL, Patratu (under construction) Useful Volume: 4019 m3 Hearth Diameter: 12.6 m Production: Presently ~ 8000 tpd Cooling System: Copper staves SGP - SVAI RASA system GCP - SVAI system Hot blast system - SVAI design PCI system - SVAI design BSP, BF # 8 (under advanced stage of execution) Hearth Diameter: 13.4 m Production: 2.8 Mtpa (8400 tpd) SGP - PW INBA system GCP - PW Annular Gap Scrubber Top charging - PW BLT system Hot blast system - PW design PCI system - PW design

Some Broad Details of Major Modern Indian BFs Technology Supplier Client Major Technical Data Remarks Paul Wurth BPSL, BF #2 (under advanced stage of execution) Useful Volume: 1701 m3 Number of Tuyeres: 24 Hearth Diameter: 8.7 m Production: 1.33 Mtpa (3800 tpd) Cooling System: Copper staves SGP - PW INBA system GCP - PW Annular Gap Scrubber TRT - 6 MW (design) Top charging - PW BLT system Hot blast system - PW design PCI system - PW design BSL, BF # 2 (commissioned – 2010) Useful Volume: 2585 m3 Number of Tuyeres: 28 Hearth Diameter: 10.2 m Production: 4500 tpd SGP – Under Implementation TRT – Not provided Hot blast system – Existing modified PCI system – Chinese design Danieli Corus BV & MECON Limited BSP, BF # 7 (commissioned – 2007) Useful Volume: 2355 m3 Hearth Diameter: 9.75 m Production: 1.5 Mtpa (4430 tpd) SGP – Existing Russian system Hot blast system – Existing Russian design PCI system - DC design Siemens VAI RINL, BF # 1 (under commissioning) Useful Volume: ~ 3800 m3 Number of Tuyeres: ~ 32 Hearth Diameter: ~ 12.5 m Production: ~ 2.6 Mtpa (~ 7500 tpd) GCP - SVAI Annular Gap Scrubber TRT – Existing System retained Hot blast system – Existing Russian design (proposal for up gradation) PCI system – Being implemented

Some Broad Details of Major Modern Indian BFs Technology Supplier Client Major Technical Data Remarks Danieli Corus BV & MECON Limited JSW, BF # 2 (commissioned) Useful Volume: 1681 m3 Number of Tuyeres: 20 Hearth Diameter: 8.4 m Production: 1.25 Mtpa (3625 tpd) Cooling System: Copper plate coolers SGP - DC Dewatering Wheel GCP – DC Bischoff system TRT - Not envisaged Top charging - TOTEM BRCU system for Jindal & PW BLT system for Bhushan Hot blast system & PCI system – Danieli Corus Apart from above medium to large size BF installations, entrepreneurs in MBF Sector are also increasingly adopting modern BF cooling system, Bell Less Top (BLT), high capacity cast house equipment, high temperature stoves including Top Fired Stoves, coal injection system & use of higher percentage of prepared burden are being increasingly preferred.

Modern Ironmaking Practices Improved cooling system and refractory design alongwith optimum instruments Proper burden distribution for proper central working, permeable deadman and reduced heat loss High hot blast temperature and high top pressure BF operation Nitrogen lean operation i.e., oxygen enrichment upto 4 – 6 % Probes and instruments, particularly for controlling large BFs Improvement in raw material qualities w.r.t. chemistry, consistency, granulometry & ratio of prepared burden Provision of facilities for pollution control and environment friendly

Important BF Design/ Operating Parameters Some important BF design/ operating parameters affecting plant campaign life and its productivity are: High BF top pressure High hot blast temperature BF top charging equipment BF refractory & cooling system Stock house configuration & charging system Raw material quality Auxiliary fuel injection Instrumentation & Automation Energy monitoring and pollution control measures

Heat Load Fluctuation w.r.t Type of Operation & Burden Mix Following table provides insight on peak heat load conditions alongwith typical heat load fluctuations (oC/ min) Type of operation Burden mix Productivity on Working vol. Peak heat load KW/m2 Heat load Fluctuation (°C/min) Low productivity Iron Ore lump < 1.5 10 – 40 6 – 10 Medium productivity Lump + Sinter 1.5 – 2.2 25 – 95 15 – 50 50 – 190 35 – 70 High productivity > 80% Sinter + < 20% Lump 2.2 – 2.7 70 – 250 50 – 105 > 30% Pellet + 50% Sinter + Balance Lump 100 - 450 100 – 190 In consideration to high productivity & long campaign life requirement, use of copper staves/ plates in contamination free closed loop soft water circuit alongwith compatible good quality refractory is desirable

Effect of Various Parameters on BF Productivity & Fuel Rate Sl. No. Item (Parameters) Base Value Change Productivity Coke Rate 1. Hot Blast Temperature 700 – 900 ° C + 100 0C + 3 %  3 % 900 – 1000 ° C + 2 %  2.5 % 1000 – 1100 ° C + 1.5 %  1.5 % 2. Fe% in lump ore 62% + 1 % 1.0 % 3. Fe% in Sinter/ Pellet 4. Ash% in coke 15 % + 1%  2 % 5. Sinter% in Burden 70 % + 10 % + 2.5 % 2.5 % 6. BF top pressure 1.0 atg + 0.1 % 7. Burden Distribution: PW BLT/ TOTEM Two Bell Yes - 2.0 % 8. Si% in Hot Metal 0.5%  (4 - 12) % + (5-15)% 9. Raw Lime Stone/ Flux + 10 Kg - 0.5 % + 3 Kg 10. Slag rate + 10 kg  0.5 % + 3 kg 11. Fluctuation in Fe 1.0 % to 0.5 % + 2.0 % 12. Addition of Metallic 10 Kg + 0.6 % Source – Metallurgist Russian Handbook

Internationally Benchmarked BFs Design/ Operating Parameters Unit Danieli Corus BF # 7, Ijmuiden, Netherlands POSCO PWIT BF # 2, Thyssen Germany Baoshan Steel BF # 1 & 2 Inland Corp., USA NDK BF # 3, NSC, Kimitsu, Japan BF # 2 Gwangyang Steel Works & BF # 3 Pohang Steel Works BF # 1 & 5 Useful volume (UV) m3 4450 4350 4020 4063 4403 Working Volume (WV) 3790 3685 3445 4769 3525 3739 3545 Sinter in burden % 42 - 50 76 74 85 85 – 86 11 - 12 100 Pellets in 44 - 50 8.2 12 10 NIL 85 - 86 Iron ore lump In burden % (max) 6 15.8 14 14 – 15 No. of tuyeres - 38 36 44 O2 enrichment 15 10-12 8-10 4-6 4

Internationally Benchmarked BFs Design/ Operating Parameters Unit Danieli Corus BF # 7, Ijmuiden, Netherland POSCO PWIT BF # 2, Thyssen Germany Baoshan Steel BF # 1 & 2 Inland Corp., USA NDK BF # 3, NSC, Kimitsu, Japan BF # 2 Gwangyang Steel Works & BF # 3 PohangSteel Works BF # 1 & 5 Production t/d 8412 -10,632 9000 9230 11500 9025 10200 9250 Productivity (on WV) t/m3/d 2.2 – 2.8 2.37 2.68 2.41 2.17 2.5 Top pressure bar 2.2 2.8 2.65 2.8-3.0 Hot blast Temperature 0C 1250 1150 – 1200 1150 - 1200 1200 Coke rate kg/thm 285 - 295 333 356 290-300 430 429 303 Coal dust injection 200 - 240 200 177 – 189 200-210 75 27 (NGI) 203 Si in Hot metal % 0.40 0.4 0.42 0.3 0.6

Internationally Benchmarked BFs Design/ Operating Parameters Unit Danieli Corus BF # 7, Ijmuiden, Netherlands POSCO PWIT BF # 2, Thyssen Germany Baoshan Steel BF # 1 & 2 Inland Corp., USA NDK BF # 3, NSC, Kimitsu, Japan BF # 2 Gwangyang Steel Works & BF # 3 Pohang Steel Works BF # 1 & 5 Slag rate kg/thm 216 - 260 267 275 - 282 285 295 290 265 - 280 Coke ash % 10.9 11 10.5 10.6 Charging system - Bell Less Note: The biggest Blast furnace of more then 5000m3 with productivity around 2.5/d/m3 have also been installed in number of countries like Japan, South Korea, Russia, Germany etc.

Indian Scenario Indian Ironmaking has come of age with increased consciousness amongst operators to meet the requirements of competitive iron making at reduced cost with “Green Technologies” The need of the hour is to adopt cutting edge innovative technologies to achieve: Cost reduction Improve specific consumption Increase energy efficiency Improve quality, yield & productivity Increased automation & adopting ergonomic practices with a focus on environmental aspect

Present Trend in India The present trend in India generally covers around the following major ideas: Installation of bigger and large BFs to achieve economies of scale Facilitating high productive operation at par with global benchmark Increased stress on auxiliary fuel injection Extensive use of energy saving measures and energy heat recovery systems Increased awareness for quality and consistent raw materials Compact installation and improved operating practices Extensive automation and controls Facilities for pollution control and environment friendly Long campaign life of around 20 years Use of top recovery turbine (TRT) for captive power generations.

Basic Design Features of Modern Indian BFs Some of the basic design features embedded as an integral design concept for modern large BFs of India are: Design suitable for long campaign life of 15 to 20 years High intensification levels of production > 2.0 t/ m3 WV/ day Closed circuit cooling for efficient and contamination free cooling High top pressure operation (1.5 – 2.5 atg) Straight line HBT of 1200 – 1250 0 C PCI level > 120 kg/ thm Installation of Top Recovery Turbine (TRT) – 14 MW for 4000 m3 BF 100 % slag granulation with dewatering facilities Advanced charging practices and high levels of Instrumentation & automation Maximum use of prepared burden, centre coke charging, two fraction sinter charging, base blending etc. Extensive use of VVVF drives Compulsory defuming and dedusting facilities Advance technologies for environment friendly.

Mini Blast Furnace Sector – Indian Perspective Even in Mini Blast Furnace (MBF) sector, plants are being built in 250 to 450 m3 size range with refractory & cooling system capable for longer campaign life of ~ 10 years & productivity levels of more than 2.5 t/ m3/ day on working volume basis. Some of the MBFs in this segment, such as Adhunik (Rourkela), Jindal SAW (Bhuj), JSPL (Raigarh) & ECL (Kolkata) have touched 3.0 t/ m3/ d productivity levels quite consistently. Some of these MBFs have incorporated sinter charging (~ 50%) in burden & have injected ~70 kg/ thm PCI. Top fired stoves for achieving 1200 °C hot blast temperatures are already implemented at Sunflag & Kirloskar with good results

Conclusions BF productivity largely depends on: BF top pressure Hot blast temperature Auxiliary fuel injection Burden distribution and control BF refractory and cooling system Quality of input raw materials BF stock house and charging system Automation and Control Increase of Oxygen content in blast While configuring the BF plant, various design & operating parameters have to be selected in line with intensified operations similar to international benchmarks. However, due consideration to available raw materials & operating conditions have to be kept in mind.

REFERENCES Metallurgists Russian Hand book. 1976 2. Modern Blast furnace – Mr. M Geerdes, H Toxopous, C Vardesvliet 3. International Seminar on “ Iron Making in Blast Furnaces” organized by “Steel Tech” in September 2010 at Kolkata

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