DESIGN FEATURES OF INDIAN BLAST FURNACES
A Mondal , SK Bhattacherjee ,SK Verma, K.R.Pal Chaudhuri,
MECON Limited
Email: [email protected]
ABSTRACT
The Blast Furnace (BF) route for iron making will remain commercially successful for the
coming decades owing to several reasons, viz., slow progress of alternative iron making
processes coupled with their high risk investments compared to BF route, availability of
mega module BFs of ~ 4000 m3 or 5500 m3 volumes for single installation capacities of 3.0
– 4.5 MT, possibility of upgrading existing BFs with advanced features at economical cost
index and ever improving BF performance indices.
In India, the BF route of iron making has witnessed constant incremental improvements in
design features to achieve maximum productivity, lowest possible coke rate, mechanized
operations, adopting best environmental practices, constant endeavour to lower the
production & operating costs and efforts to utilise maximum indigenously available raw
materials.
The aforesaid objectives have provided an indirect opportunity for innovations and
advancements in BF design & technology base.
In tandem with the performances of globally benchmarked BFs, Indian operators are
keeping pace with modern BF productivity levels and we have lately witnessed the
emergence of state of the art BF installations, viz., TATA STEEL BF # G & H, JSW BF #
2,3&4, JSPL BF # 2 and other BFs at Bhushan Steel & SAIL (BSP BF # 7& 8 & BSL BF #
2&4 RSP# BF5, ISP# BF5 ). Even in the MBF route, more & more entrepreneurs are
looking to adopt state of the art design features to achieve better techno - economic
parameters. Inefficient BF operation technologies with lower hot blast temperature & low
top pressure are being dispensed with and intensified cooling systems to cater to auxiliary
fuel injection & sinter charging in BF burden are being increasingly adopted in MBF
sector also resulting in longer campaign life & lower cost of production.
DESIGN FEATURES OF INDIAN BLAST FURNACES
Page 1 of 12
MECON has been long associated with the development of small & medium sized BFs and
is the only Indian organization which successfully developed its own indigenous in – house
design of BF proper, hot blast stoves, fully flat & covered cast house & auxiliaries.
This paper attempts to highlight the design features of Indian BFs and bring the
technology status of existing as well as proposed Blast Furnace installations both in large
& mini sectors to help operators & entrepreneurs have a better understanding of the
current trend.
Keywords: Design Features of Indian BFs
INTRODUCTION
The Blast Furnace (BF) technology for iron making will continue to be the dominant route
for hot metal production in the coming years owing to various reasons such as:

Only Corex – Finex – Hismelt technologies under alternative iron making
processes have reached actual commercial production stage. However, higher
capacity modules are yet to be established in the global market.

Investment in alternative processes has elevated business risks as compared to BF
route and as such its installation possibility is mostly explored through MOU with
technology suppliers only

Requirement of rapid expansion programme by the year 2025 under national
steel policy, which necessitates adding large production modules of 3.0 / 4.5 MT
possible through commercially proven BF route only

Upgradation & modification of existing BFs for augmented hot metal production
is less capital cost intensive in comparison to building new installations through
alternate route technology

Possibility of improvement in performance of BF in terms of productivity, cost &
environmental friendliness
The Indian steel industry is presently witnessing unflinching government support for
unprecedented capacity expansion run and has rapidly amalgamated the state of art design
features available globally for its brown - field upgradation & new projects in the last
decade resulting in installation of following modern BF projects:
DESIGN FEATURES OF INDIAN BLAST FURNACES
Page 2 of 12

TATA Steel # G & H Blast Furnace

Bhilai Steel Plant # Blast furnace 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 Steels # Blast Furnace No.1 & 2 ( under commissioning)
Table 1.0: Some broad details of major modern BFs in India are shown in Table below:
Technology
Supplier
Client
Major Technical Data
Remarks
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 # H
(commissioned - 2008)
Tata Steel, BF # I (under
design & erection)
Paul Wurth
RINL, BF # 3
(under commissioning
trials)
Bhushan Steel, BF # 2
(under construction)
POSCO
e&c
Paul Wurth
Danieli Corus
BV
ISP, New BF
( commissioned in Nov
2014)
Tata Steel, BF # G
(Revamped in 2005)
RSP, BF # 5
(commissioned in 2013)
DESIGN FEATURES OF INDIAN BLAST FURNACES
SGP - Rasman Screw
type
GCP - Bischoff Annular
Useful Volume: 4161 m3
Gap system
Number of Tuyeres: 38
TRT – 14to 18 MW
Hearth Diameter: 13.6 m
(Mitsui& Nico )
Production: 2.8 Mtpa (8000
Top charging- PW
tpd)
BLT system
Cooling System: Copper staves Hot blast system Danieli Corus
PCI system –
CISRI/NMT/SPCL
Useful Volume: 2648 m3
Double cast house
Number of Tuyeres: 30
PW BLT system
Hearth Diameter: 11.05
PW GCP (Tangential
Production: 1.8 Mtpa (5150 tpd)
cyclone + two stage
Cooling System : Copper staves
venturi scrubber)
Useful Volume: 4060 m3
SGP - DC Dewatering
Number of Tuyeres: 36
Wheel
Hearth Diameter: 13.2 m
GCP – DC Bischoff
Production: 2.8 Mtpa (7984
system
tpd)
TRT - 14 MW (design)
Cooling System: Copper plate
Top charging - PW
coolers
BLT system
Page 3 of 12
JSW Steel (BF # 3 & 4)
(BF # 3 commissioned 2009
BF # 4 under
commissioning)
JSPL, Patratu (under
construction)
Useful Volume: 4019 m3
Number of Tuyeres: 36
Hearth Diameter: 12.6 m
Production: Presently ~ 8000
tpd
Cooling System: Copper staves
BSP, BF # 8
(under advanced stage of
execution)
Useful Volume: 4060 m3
Number of Tuyeres: 36
Hearth Diameter: 13.4 m
Production: 2.8 Mtpa (8400
tpd)
Cooling System: Copper staves
BPSL, BF #2
(under execution)
Useful Volume: 1701 m3
Number of Tuyeres: 24
Hearth Diameter: 8.7 m
Production: 1.33 Mtpa (3800
tpd)
Cooling System: Copper staves
BSL, BF # 2
(commissioned – 2010)
Useful Volume: 2585 m3
Number of Tuyeres: 28
Hearth Diameter: 10.2 m
Production: 4500 tpd
Cooling System: Copper staves
Danieli Corus
BV &
MECON
Limited
BSP, BF # 7
(commissioned – 2007)
Useful Volume: 2355 m3
Number of Tuyeres: 24
Hearth Diameter: 9.75 m
Production: 1.5 Mtpa (4430
tpd)
Cooling System: Copper staves
Siemens VAI
RINL, BF # 1
(under commissioning)
Useful Volume: ~ 3800 m3
Number of Tuyeres: ~ 32
Siemens VAI
Paul Wurth
Paul Wurth
Paul Wurth
DESIGN FEATURES OF INDIAN BLAST FURNACES
Hot blast system Danieli Corus
PCI system - Danieli
Corus
SGP - SVAI RASA
system
GCP - SVAI system
TRT - 14 MW (design)
Top charging - PW
BLT system
Hot blast system SVAI design
PCI system - SVAI
design
SGP - PW INBA
system
GCP - PW Annular
Gap Scrubber
TRT - 14 MW (design)
Top charging - PW
BLT system
Hot blast system - PW
design
PCI system - PW
design
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
SGP – Under
Implementation
GCP - PW Annular
Gap Scrubber
TRT – Not provided
Top charging - PW
BLT system Hot blast
system – Existing
modified PCI system –
Chinese design
SGP – Existing Russian
system
GCP - PW Annular
Gap Scrubber
TRT – Not provided
Top charging - PW
BLT system
Hot blast system –
Existing Russian design
PCI system - DC design
SGP – Existing Russian
system
Page 4 of 12
Hearth Diameter: ~ 12.5 m
Production: ~ 2.6 Mtpa (~
7500 tpd)
Cooling System: Copper staves
Danieli Corus
BV & ECON
Limited
JSW, BF # 2
(commissioned - 2006)
Useful Volume: 1681 m3
Number of Tuyeres: 20
Hearth Diameter: 8.4 m
Production: 1.25 Mtpa (3625
tpd)
Cooling System: Copper plate
coolers
GCP - SVAI Annular
Gap Scrubber
TRT – Existing System
retained
Top charging - PW
BLT system
Hot blast system –
Existing Russian design
(proposal for up
gradation)
PCI system – Being
implemented
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 blast furnace installations, entrepreneurs in MBF
sector are also increasingly adopting modern BF cooling system, bell less top charging
system, high capacity cast house equipment, high temperature stoves including top fired
stoves, coal injection & use of higher percentage of prepared burden.
Today, Indian BF operators are fully aware of advantages of modern iron making design &
practices and are working to achieve primarily followings goals:


Increased pulverised coal injection (~200 Kg/ thm) & high blast furnace
productivity (~2.5 t/ m3 WV/ d)
Reduction in CO2 emission by decreasing heat losses & improving energy
efficiency.

Pollution friendly equipment

High campaign life
The above can be achieved by adhering to followings operating regime/ practices:

Improvement in raw material qualities with respect to chemistry, granulometry,
consistency & prepared burden ratio particularly for large BFs

Improved cooling system & refractory design alongwith optimum instrument
feedback for longer campaign life
DESIGN FEATURES OF INDIAN BLAST FURNACES
Page 5 of 12

Proper burden distribution for central working, permeable dead man & reduced
heat loss

High hot blast temperature & high top pressure BF operation

Nitrogen lean operation i.e.; O2 enrichment up to 4 – 6 %

Various modern probes & instruments particularly for controlling large BFs

Provision of facilities for pollution control & environment friendly
The present paper describes the design features of existing as well as proposed blast
furnaces & suggests roadmap for future upgradation & modernization of BF projects.
IMPORTANT BF DESIGN/ OPERATING PARAMETERS
Some of the important BF design/ operating parameters affecting plant campaign life & its
productivity are discussed below:
High BF top pressure:
High BF top pressure is a pre - requisite of high productivity & high efficiency BF
operation. High top pressure ensures better permeability, longer gas solid reaction time and
better fuel rate. Beside increase in productivity level and decrease in fuel rate, high top
pressure also enables incorporation of top recovery turbine, which makes the plant energy
efficient.
High hot blast temperature:
This is another important parameter for high productivity BF operation with reduction in
fuel rate. Higher hot blast temperature along with provision of O2 enrichment ensures
smooth auxiliary fuel injection such as pulverised coal injection.
BF top charging equipment:
Considering the precise burden distribution control required for operation of large capacity
BF, bell less design has been found most appropriate and has been adopted world wide.
BF refractory & cooling system:
The selection of BF refractory & cooling system shall have considerations for high
productivity and longer campaign life.
Provision of Facilities to meet Environment norms like Cast house and stock house
dedusting system
DESIGN FEATURES OF INDIAN BLAST FURNACES
Page 6 of 12
The following table provides insight on peak head load conditions alongwith typical heat
load fluctuation (°C/ min) with respect to type of operation & burden mix.
Table 2.0: peak head load conditions alongwith typical heat load
Burden mix
Productivity on
working volume
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
Medium productivity
Lump + Sinter
1.5 – 2.2
50 – 190
35 – 70
High productivity
> 80% Sinter + <
20% Lump
2.2 – 2.7
70 – 250
50 – 105
High productivity
> 30% Pellet +
50% Sinter +
Balance Lump
2.2 – 2.7
100 - 450
100 – 190
Type of operation
In consideration to high productivity and long campaign life requirement, use of copper
staves/ plates alongwith compatible high spalling resistance & high conductive refractory
materials is most suited and adopted world wide.
Stock house configuration & charging system:
Considering the various burden mix being used world over, provision should be made for
40% to 80% sinter in burden, 10% to 30% of pellets in burden & 10% to 30% of iron ore
lump in burden. Besides the above ferrous burden requirements, coke charging shall be
done in 2 to 3 fractions with nut coke charging facility.
Force filling capacity the charging system shall be designed to cater to > 3 t/ m 3/ d
productivity level. In order to optimize the project cost, screen/ feeder capacities shall be
selected such that inter changeability of day bins between sinter/ pellet/ lump is possible.
Raw material quality:
Consistency in input materials is of paramount importance for smooth operation of large
BFs. Considering the typical Indian raw material quality/ characteristics, a reasonable
approach is required for suggesting the input material quality to be fed consistently.
Moderate good quality coke having 14 -15% ash, CSR: 60 - 64 & M 10: 7/ 8 (max.) is
suggested. The performance of BF can improve with improvement in coke quality in line
with international practice.
Auxiliary Fuel Injection (PCI):
DESIGN FEATURES OF INDIAN BLAST FURNACES
Page 7 of 12
In line with the achieved PCI rates in large BFs, pulverised coal injection capable of
injecting 200 kg/ thm is proposed.
A Table is given below, wherein all the aforementioned parameters alongwith its variations
and its effect on BF productivity and fuel rate are shown:
Table 3.0: parameters alongwith its variations and its effect on BF productivity and fuel
rate
Sl.
No.
Base Value
Change
Productivity
Coke Rate
700 – 900 ° C
+ 100 0C
+3%
3%
Hot Blast Temperature
900 – 1000 ° C
+ 100 0C
+2%
 2.5 %
+ 100 C
+ 1.5 %
 1.5 %
2.
Fe% in lump ore
1000 – 1100 °
C
62%
+ 1%
+2%
1.0 %
3.
Fe% in Sinter/ Pellet
+ 1%
+2%
1.0 %
4.
Ash% in coke
15 %
+ 1%
2%
+ 2.0 %
5.
Sinter% in Burden
70 %
+ 10%
+ 2.5 %
2.5 %
6.
BF top pressure
1.0 atg
+ 0.1%
+1%
1.0 %
7.
Burden Distribution: PW
BLT/ TOTEM
Two Bell
Yes
+2%
- 2.0 %
8.
Si% in Hot Metal
0.5%
+ 1%
 (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 %
- 2.0 %
12.
Addition of Metallic
10 Kg
+ 0.6 %
- 0.5 %
13
Cooling losses kj/hr
+10
-
+1.2
1.
Item (Parameters)
0
(Source: Metallurgist’s Russian Handbook, 1976)
From the above, it can be seen that with various raw material and operating parameters, the
performance of BF is greatly affected.
INTERNATIONAL BENCHMARKS
Following data have been collected on similar BFs working elsewhere in the world to
benchmark the design/ operating parameters for Indian BFs:
DESIGN FEATURES OF INDIAN BLAST FURNACES
Page 8 of 12
Table 4.0: Design/ operating parameters for BFs( in brief)
Design/
Operating
Parameter
s
Useful
volume
(UV)
Working
volume
(WV)
Sinter in
burden
Pellets in
burden
Iron ore
lump in
burden
No. of
tuyeres
O2
enrichment
Production
Productivit
y (on WV)
Top
pressure
Hot blast
Temperatur
e
Coke rate
Coal dust
injection
Si in hot
metal
Slag rate
Coke ash
Charging
system
Unit
POSCO
Danieli
BF # 2
Corus
Gwangyang BF # 1 & 5
BF # 7,
Steel Works Gwangyan
Ijmuiden,
& BF # 3
g Steel
Netherlands Pohang Steel
Works
Works
PWIT
BF # 2,
Thyssen
German
y
Baoshan
Steel
BF # 1
&2
Inland
Steel
Corp.,
USA
NDK
BF # 3,
NSC,
Kimitsu,
Japan
4063
4403
4063
m3
4450
4350
4020
m3
3790
3685
3445
4769
3442
3739
3442
%
42 - 50
76
74
85
85 – 86
11 - 12
100
%
44 - 50
8.2
12
10
NIL
85 - 86
-
%
(max)
6
15.8
14
14 – 15
2
-
38
38
36
44
36
10-12
10
8-10
4-6
4
4-6
9000
9230
11500
9025
10200
9250
2.37
2.68
2.41
2.17
2.5
2.5
2.2
2.8
2.65
2.8-3.0
2.5
2.5
2.5
1250
1150 – 1200
1150 - 1200
1200
1200
1250
1200
285 - 295
333
356
290-300
430
429
303
200 - 240
200
177 – 189
200-210
75
27
(NGI)
203
0.42
0.4
0.3
0.6
%
15
(max)
t/d 8412 -10,632
t/m3
2.2 – 2.8
/d
bar
0
C
kg/
thm
kg/
thm
%
kg/
thm
%
-
0.40
36
216 - 260
267
275 - 282
270-280
325
305
320
10.9
11
11
11
11
12
Bell Less
Bell Less
Bell Less
Bell Less
Bell Less
12
Bell
Less
Bell Less
Note: The biggest Blast furnace of more than 5000m3 with productivity around 2.5/d/m3
have also been installed in number of countries like Japan, South Korea, Russia, Germany
etc.
DESIGN FEATURES OF INDIAN BLAST FURNACES
Page 9 of 12
INDIAN SCENARIO
Indian iron - making has come of age with increased consciousness amongst operators to
meet the requirements of competitive iron making at reduced cost high productivity,
energy efficient with “green technologies”. The need of the hour is to adopt cutting edge
innovative technologies to achieve cost reduction method, improve specific consumption
of raw materials, increase energy efficiency, improve quality, yield & productivity,
increased automation, adopting ergonomic practices with a focus on environmental aspect.
To achieve the aforesaid multiple perspectives, the present trend in India generally covers
around the following major ideas:
a)
Installation of bigger and larges BFs to achieve economies of scale
b)
Facilitating high productivity operation at par with global benchmarks
c)
Increased stress on auxiliary fuel injection
d)
Extensive use of energy saving measures and energy/ heat recovery systems
e)
Increased awareness for quality & consistent raw materials
f)
Compact installations and improved operating practices
g)
Extensive automation & controls
h)
Facilities for pollution control & environment friendly.
i)
Long campaign life of around 20 years
j)
Use of Top recovery turbine (TRT) for captive power generations.
It may be noticed that most of the large BFs in India commissioned in the recent past have
been built with technology levels comparable with the best across the globe. The emphasis
on technology & process route selection has gained momentum with increased
consciousness of the prevailing open market scenario.
Some of the basic design features which have been embedded as an integral design concept
for the several large BFs commissioned (or under design/ construction) are as follows:
a)
Design suitable for long campaign life of ~ 15 to 20 years
b)
High intensification levels of production > 2.0 t/ m3 WV/ day
c)
Closed circuit soft water cooling for efficient & contamination free cooling and
less make – up water requirement
DESIGN FEATURES OF INDIAN BLAST FURNACES
Page 10 of 12
d)
High top pressure operation (1.5 atg to 2.5 atg)
e)
Straight line hot blast temperature of ~ 1200 ° C to 1250 ° C
f)
Pulverised coal injection (PCI) levels of > 120 kg/ thm
g)
Installation of top recovery turbine (TRT) – 14 to 18 MW for 4000 m3 BF
h)
100 % slag granulation with continuous dewatering facilities
i)
Advanced charging practices & high levels of automation
j)
Maximum use of prepared burden, centre coke charging, two fraction sinter
charging, base blending and the like
k)
Extensive use of VVVF drives
l)
Compulsory defuming & dedusting facilities
m) Advanced technologies for environment friendly.
Even in Mini Blast Furnace 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
level of more than 2.5 t/ m3/ d on working volume basis. Some of the blast furnace in this
segment such as 262 m3 MBF at M/s Adhunik, Rourkela, Jindal SAW, Jindal, Raipur &
ECL, Kolkata has touched 3.0 t/ m3/ d productivity levels quite consistently. Some of these
blast furnaces have incorporated sinter charging (~ 50%) in the burden & have injected ~70
kg/ thm PCI. Top fired Stoves for achieving 1200 ° C hot blast temperatures are already
implemented at Sunflag & Kirloskar BFs with good results.
It may be noted that although the Fe content of Indian iron bearing materials is more or less
comparable, the Al2O3 content of the same is > 2.0 % in comparison to < 1.5 % world
wide. Higher Al2O3 in burden compel the Indian BF operators to generate more slag in the
BF in order to keep low Al2O3 % in slag. High Al2O3 slag reduces the slag viscosity
particularly at the bosh level (bosh slag) leading to flooding during high productivity
operation.
In this connection, it is important to mention that most of the iron ore imported from India
by different countries is blended with low Al2O3 iron ore from other sources for use in high
efficiency BFs abroad.
Similarly, it may not be advisable to aim for low ash (about 10 %) coke in India as used in
high productivity BFs abroad since this requires the use of ~ 100 % imported coal
DESIGN FEATURES OF INDIAN BLAST FURNACES
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purchased from selected countries in spite of having deposits of prime/ medium coking
coal in the country.
A number of BFs abroad use metallic input like HBI/ scrap for achieving high hot metal
production rate which is not extensively considered in India due to several economic
considerations. However, facilities for charging of DRI have been considered for the new
4000 m3 BFs.
CONCLUSION
It can be concluded that the productivity of BFs is largely dependant on following factors:
 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 & charging system
 Automation and Control
 Increase of oxygen content in blast
Review of design and operating parameters of benchmarked large BFs globally suggest the
present operating level of around 2.2 – 2.8 t/ m3/ day on working volume basis.
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
1. Metallurgists Russian Hand book, 1976
2. Modern Blast Furnace Iron making - 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.
DESIGN FEATURES OF INDIAN BLAST FURNACES
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