Project report of my project "effect of moisture content on turndown temperature

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EFFECT OF MOISTURE CONTENT ON
TURNDOWN TEMPERATURE AT LD#1
SUMMER INTERNSHIP 2017
PRESENTED BY:
Keerthik Mohanan
Kevin George
Under the auspice of
Mr. Amarnath Mukherjee, Sr. Manager PSM,LD1
Mr. Abhinav Singhvi, Manger PSM,LD 1

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DECLARATION
I Keerthik Mohanan student of Mahatma Gandhi University Id No 14002956
hereby declare that the internship Report is submitted by me in partial
fulfilment of the requirement for the award of the degree of Bachelor of
Technology
Place: Jamshedpur
Date: 11-08-2017

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CONTENTS
1) Acknowledgement
2) The TATA group
3) TATA steel
4) Plant layout
5) Importanceof steel
6) Overview of the BOS process
7) BOF structureside
8) Hot metal
9) Oxygen Lance technology
10) Basic operation
11) Importanceof slagin LD
12) Iron oreaddition
13) Blow practices
14) Turndown conditions
15) Blowing controland turndown
16) Turndown control
17) Correction of temperature and analyses
18) Reblow
19) The automation model
20) Problem facing in LD1
21) Cause and effect diagram
22) Aim
23) Sample study and moisturetesting
24) Calculation work
25) Heat Comparison of wet and dry iron ore

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Acknowledgement
Great success can only be attained when we have the shoulders of colossus to
stand over and look yonder. At Tata Steel we met people who have excelled in
their respective fields. They have proved time and again that they are the ones
who are shaping the presentand future of this great institution. Holding our
hands, they haveguided us through this endeavour, morphing and shaping the
technical as well as operational aspect of our outlook
Mr Amarnath Mukherjee, Sr Manger primary steel making, LD#1 our guide who
gave us his precious time; shared with us his insight and experiences,
appreciated us and inspired us throughoutour stay we thank him profusely for
being a wonderfulmentor.
Mr. Zachariah Chacko our co-guide is acknowledged for being our pillar of
strength and our motivator who made us dream big and channelled our efforts
in the right direction
Mr Abhinav Singhvi, who constantly oversaw our proceedings and who left no
stone unturned to make our experience at Tata Steel wonderful.
Sincere thanks to SNTI team for making all the arrangement and safety
training.
I would like to thank my own College, AMAL JYOTHI COLLEGEOF ENGINEERING
and Department of Metallurgy for giving us an opportunity to do an internship
at TATA Steel
Special thanks to all the operators at PSM, LD1, who contributed selflessly in
making us understand the whole working of the vesseland controlroom.
A special thanks to everyoneat TATA Steel who touched our lives in the due
courseand made us feel at home. We are proud to visitthis beautiful city of
Jamshedpur
Keerthik Mohanan
Kevin George

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The TATA Group
The TATA Group: A Legacy of Trust
TATA is India’s largestand most diversified business conglomeratewith more
than 100 operating companies spread over 85 countries in six different
continents, employing 350,000 people, TATA companies share fivecore values-
 Integrity
 Understanding
 Excellence
 Unity
 Responsibility
Each TATA company agrees to the TATA code of conduct by signing the TATA
Brand Equity and Business Promotion Agreement with TATA Sons Ltd. This
ensures adherenceto the TATA ethos and value system. Adherenceto ethics
and excellence and the commitment towards serving communities have been
at the core of TATA’s unblemished growth and sustenancefor over 140 years.
This heritage evokes trustand goodwill among consumers, employees,
shareholders and the larger community. Today, the TATA name is a unique
assetrepresenting ‘Leadership with Trust’. This legacy has earned the
admiration of the group’s stakeholders in a manner few business houses can
ever hope to match.
The business operations currently encompass seven business sectors namely:
 Engineering
 Materials
 Services
 Energy
 Customer products,
 Communications and IT,
 Chemicals

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The major companies in the group of TATA include:
 TATA Steel
 TATA Motors
 TCS
 TATA Power
 TATA Chemicals

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TATA Steel
Established in 1907, TATA Steel is more than 100 years old company and is
among the top ten Global Steel companies. Itis now one of the world’s most
geographically-diversified steel producers, with operations in 26 countries and
a commercial presence in over 50 countries.
The TATA Steel Group, with a turnover of US$ 22.8 billion in FY’ 10, has over
80,500 employees across fivecontinents and is a Fortune 500 company.
TATA Steel’s vision is to be the world’s steel industry benchmark through the
excellence of its people, its innovativeapproach and overall conduct.
Underpinning this vision is a performanceculture committed to aspiration
targets, safety and social responsibility, continuous improvement, openness
and transparency.
TATA Steel’s larger production facilities include those in India, the UK, the
Netherlands, Thailand, Singapore, China and Australia. Operating companies
within the group include TATA Steel Limited (India), TATA Steel EuropeLimited
(formerly Corus), Natsteel, and TATA Steel Thailand (formerly Millennium
Steel).
TATA Steel has believed that the principle for mutual benefit- between
countries, corporations, customers, employees and communities- is the most
effective route to profitable and sustainable growth.
TATA Steel limited is a multinational steel company headquartered in Mumbai,
India and subsidiary of TATA group. It is the tenth largest steel producing
company in the world with an annual steel crude capacity of 23.88 million
tonnes(FY17), and the second largest steel company in India(measured by
domestic production) with an annualcapacity of 9.7 million tonnes after SAIL.
Tata Steel’s largest plant is located in Jamshedpur, Jharkhand, with its recent
acquisitions; the company has become a multinational with operations in
various countries. The company is listed on Bombay Stock exchange and
National Stock Exchange of India and employs about 80,500 people.
Tata Steels products include:

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 Cold/hot rolled coils and sheets
 Billets
 seamless bars(RCS, RDS & Gothic bars)
 forged rounds
 rolled & forged rings
 tubes & bearings
In an attempt to ‘ decommoditise’ steel, the company has introduced brands
like:
 Tata Steelium (the world’s firstbranded cold rolled steel)
 Tata Shaktee (galvanazed corrugated sheets)
 Tata Tiscon (rebars)
 Tata Bearings
 Tata Agrico (Hand tools and implements)
 Tata Wiron (galvanized wireproducts)
 Tata Pipes (Pipes for construction)
 Tata Structura (Contemporary construction Materials)
Apart fromthese productbrands, the company also hass its folds a service
brsand called ‘STEEL JUNCTION”

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The Process Flow at TATA Steel
Vision
Its vision is to be the globalsteel industry benchmarkfor value creation and
corporate citizenship.
Tata Steel achieves its vision through :
 Its People
By fostering teamwork, nurturing talent, enhancing leadership capability and
acting with pace, pride and passion.
 Its Offer
By becoming the supplier of choice, delivering premier products and services
and creating value for its customers.
 Its InnovativeApproach
By developing cutting edge solutions in technology, processes and products.
 Its Conduct
By providing a safeworkplace, respecting the environment, caring for
communities and demonstrating high ethical standards.

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AWARDS AND ACHIEVEMENTS
 Tata Steel was awarded the ‘ 2015 World’s MostEthicalCompany’
award under the Metals Category by the Ethisphere Institute. This was
the third time that Tata Steel won this award.
 The Ministry of Steel awarded Tata Steel the Prime Minister’s Trophy for
‘ Best Performing Integrated Steel Plant’ in the year 2010-11, thus
making it the eighth time that it received this award since the trophies
institution in 1992-93.
 In 2015, Tata Steel’s Climate disclosurereceived highest rating of 100 %
CDLI (Climate DisclosureLeadership Index) score.

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PLANTLAYOUT

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IMPORTANCE OF STEEL
Steel has had a major influence in our lives. The cars we drive, the buildings we
work in, the homes in which we live and countless other facets in between.
Steel is used in our electricity-power-line towers, natural-gas pipelines,
machine tools, military weapons-thelist is endless.
Steel has earned a place in our homes in protecting our families, making our
lives convenient, its benefits are undoubtedly clear.
Steel is by far the most important, multifunctional and the most adaptable of
materials. The development of mankind would havebeen impossiblebut for
steel. The backboneof developed economies was laid on the strength and
inherent uses of the steel.
The characteristics of steel are:
 Hot and cold formable
 Weldable
 Suitable machinability
 Hard, tough and wear resistant
 Corrosion resistant
 Heat resistant and Resistance to deformation at high temperatures.
Steel compared to other materials of its type has low production costs. The
energy required for extracting from ore is about 25% of whatis needed for
extracting Aluminium. Steel is environment friendly as it can be recycled. 5.6%
of element iron is presentin Earth’s crust, representing a secure raw material
base.
Steel production is 20 times higher as compared to production of all non-
ferrous metals.
The steel industry has developed new technologies and has strived hard to
make the world’s strongestand mostversatile material even better. There are

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altogether about2000 grades of steel developed of which 1500 grades arehigh
grade steels. There is still immense potential for developing new grades of
steel with varying properties.
Steel has changed our world like no other substance. New high performance
steel allows a jet pilot to reach new heights, a surgeon to perform a delicate
operation. Itis the solid rocketbooster casings that allow shuttle astronauts to
explore new frontiers and the roller coaster ridden by a child. Each piece of
steel we makeis engineered to fit precise specifications. Itis an industry where
productquantity is measured by the millions of tons, but quality is measured
by the millionth of an inch.
The same utmost precision applies to the processes employed throughout
today’s steel plant. Tata Steel is truly a high-tech industry, with automation
and advanced technologies driving the way it does its business. Someof the
most advanced technologies available today are utilised throughoutthe steel
making process, which enables the industry to maximise the efficiency while
minimising the environmentalfootprint.

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OVERVIEW OF BOF PROCESS AT LD1
Oxygen steelmaking has become the dominant method of producing steel
fromblast furnacehot metal. Although the use of gaseous oxygen (rather than
air) as the for agent for refining molten and scrap mixture to producesteel by
pneumatic processes received the attention of numerous investigator from
Bessemer onward, it was not until after World War ll that commercial success
was attained.
The primary raw materials for the BOP are 85-90% liquid hot metal from the
blast furnace and the balance is steel scrap. These are charged into the Basic

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Oxygen Furnace(BOF) vessel. Oxygen(>99.5% pure) is "blown" into the BOF at
supersonic velocities(1.5 times to that of speed of sound) and oxygen per
blow is around 7200 NM3. It oxidizes the carbon and silicon contained in the
hot metal liberating great quantities of heat which melts the scrap.Total Argon
of 25 Nm3 is purged from the bottom of the furnace for perfect stirring and to
maintain homogeneity throughout the bath during the process The post
combustion of carbon monoxide as it exits the vessel also transmits heat back
to the bath.
The product of the BOS is molten steel with a specified chemical anlaysis at
1590°C-1650°C. From here it may undergo further refining in a secondary
refining process or be sent directly to the continuous caster where it is
solidified into semi finished shapes: blooms, billets, or slabs.
Basic refers to the magnesia (MgO) refractory lining which wears through
contact with hot, basic slags. These slags are required to removephosphorus
and sulfur fromthe molten charge

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BOF- THE STRUCTURAL SIDE
An operating BOF,consists of the vessel and its refractory lining, vessel
protective slag shields, the trunnion ring, a vessel suspension system
supporting the vessel within the trunnion ring, trunnion pins and support
bearings, and the oxygen lance. It consists of a spherical bottom, cylindrical
body and conical top with a tap hole in between the conical and cylindrical
portion.
The BOF vesselconsists of the vessel shell, made of a bottom, a cylindrical
center shell (barrel), and a top cone; reinforcing component

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to the cone, such as a lip ring and top ring; auxiliary center shell and top cone
flanges for bolted-on top cones; auxiliary removable bottoms for bottom reline
access, or for individual bottom reline of bottom-blown vessels; and a taphole.
This list is not intended to be either restrictive or comprehensive, e.g., top
cone flanges are not universal.
BOF vessels can be one of the general classifications presented in. These are
top-blown vessels, in which the oxygen is injected above the hot metal bath by
means of a retractable lance; top-blown vessels, in combination with bottom
stirring, the latter usually by introducing metered amounts of inert gas at
specific locations under the hot metal bath—the introduction of the inert gas is
either through porous plugs or tuyeres; bottom-blown vessels, in which the
oxygen is injected under the molten metal bath through tuyeres arranged in
the bottom of the vessel, and usually carrying pulverized additives; bottom-
blown vessels utilizing a calculated source of heat energy provided by
hydrocarbon fuel, in a very similar arrangement as the bottom blown vessel;
and combination-blown vessels, in which the oxygen is introduced under the
bath through tuyeres in the bottom of the vessel, as well as above the bath
through a lance—the oxygen blown through the bottom usually carries
pulverized additives.
The Vessel Bottom: Itis influenced by the process and the weight balance
required to optimize the tilt drive system. The common shapeis torispherical.
For processes requiring the introduction of gases from thebottom of the vessel
(through tuyeres), the shapeof the bottom tends to be flatter than those
which have only top blowing. Also, because somebottom stirring/blowing
processes posemoreof a burden on the bottom refractory, thebottom is
designed to be interchangeable to enhance relining. For example, in the OBM
(Q-BOP) process, therefractory lining in the bottom of the vessel wears more
than twice as fastas that in the rest of the vessel. Therefore, the bottomis
replaced at mid-campaign. This also allows for the maintenance of the tuyeres.

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HOTMETAL
Hot metal is liquid iron fromthe blastfurnace saturated with up to 4.3%
carbon and containing 1% or less silicon, Si. Itis transported to the BOF shop
either in torpedo cars or ladles. The hotmetal chemistry depends on how
theblast furnaceisoperated and whatburden (iron bearing)materials are
charged to it. The trend today is to run at high productivity with low slag
volumes and fuel rates, leading to lower silicon and higher sulphur levels in
hot metals. If BOF slag is recycle, P and Mn level rise sharply sincethey report
almost 100 % to the hot metal. The sulphur level from the blast furnacecan be
0.05 % but an efficient hot metal desulfurizing facility ahead of the BOF will
reduce this to blow 0.1%.AS mentioned abovethe most common
desullphuring reagents lime, calcium carbide and magnesium – used alone or
in combination are injected into the hot metal through a lance .the sulphur
containing compound reportto the slag; however, unless the sulphur rich slsg
is skimmed before the hot metal is poured in to the BOF, the sulfur actually
charged will abovethe level expected from the hot metal analysis.

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OXYGEN LANCE TECHNOLOGY
In modern steelmaking production, a water-cooled lance is used as the
refining tool by injecting a high velocity stream of oxygen onto a molten
bath. The velocity or momentum of the oxygen jet results in the penetration of
the slag and metal to promote oxidation reactions over a relatively small area.
The jet velocity and penetration characteristics are functions of the nozzle
design. This section will discuss the design and operation of water-cooled
oxygen lances as they apply to modern steelmaking practices in the BOF.
Oxidation Reactions
The primary reason for blowing oxygen into steel is to remove carbon to
endpoint specifications. The principle reaction which results from theoxygen
lancing is the removal of carbon from the bath as CO. This is an exothermic
reaction which adds heat to the system. A small amount of CO2 is also
produced, but 90% or more is usually CO. As will be discussed later, the
burning of this CO inside the furnace by reacting with oxygen is called post-
combustion. Other elements such as Si, Mn, and P are also oxidized and are
absorbed in the slag layer. These reactions are also exothermic, further
contributing to the required heat to melt scrap and raise the steel bath to the
necessary temperature. The oxidation of the silicon is particularly important
because it occurs early in the oxygen blow and the resultant silica combines
with the addedlime to form the molten slag. Table below presents the
oxidation reactions during the steelmaking process.

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Supersonic Jet Theory
Nozzles are designed for a certain oxygen flow rate, usually measured in scfm
(Nm3/min), resulting in a certain exit velocity (Mach number), with the
required jet profile and force to penetrate the slag layer and react with the
steel bath in the dimple area.
Supersonic jets are produced with convergent/divergentnozzles, Figure below.
A reservoir of stagnant oxygen is maintained at pressure, Po. The oxygen
accelerates in the converging section up to sonic velocity, Mach = 1, in the
cylindrical throat zone. The oxygen then expands in the diverging section. The
expansion decreases the temperature, density, and pressureof the oxygen and
the velocity increases to supersonic levels, Mach > 1.
As the oxygen jet exits into the furnace, at a pressureP°, it spreads and decays.
A supersonic core remains for a certain distance from the nozzle. Supersonic
jets spread at an angle of approximately12°.
Proper nozzle design and operation are necessary both to efficiently produce
the desired steelmaking reactions and to maximize lance life. If a nozzle is
overblown, which means that the oxygenjet is not fully expanded at the time it
exits the nozzle, shock waves will develop as the jetexpands outside of the
nozzle. Useful energy is lost in these shock waves, and an overblown jet will
impact the steel bath with less force than an ideally expanded jet.
Nozzles are underblown when the jet expands to a pressure equal to the
surrounding pressure and then stops expanding before it exists the nozzle. In
this case, the oxygen flow separates from the internal nozzlesurface. Hotgases

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from the steel vessel then burn back or erode the nozzle exit area. This erosion
not only decreases the lance life, but also results in a loss of jet force, leading
to a soft blowing condition. Overblowing and underblowing conditions are
demonstrated in figure below
This figure displays the major components of the BOF oxygen lance. These
include oxygen inlet fittings, the oxygen outlet (lance tip), which is made of a
high thermal conductivity cast copper design with precisely machined nozzles
to achieve the desired flow rate and jet parameters. Cooling water is essential
in these lances to keep them from burning up in the vessel. The lance barrel is
a series of concentric pipes, an outer pipe,an intermediate pipe and the central
pipe for theoxygen. Lances must be designed to compensate for thermal
expansion and contraction. The outer barrel/pipe of the lance is exposed to the
high temperatures in the furnace. As its temperature increase it expands and
the overall lance construction internally is constructed with O-ring seals and
various joints, but can accommodate the thermal expansion and contraction
while in service. The lance also has a stress-free design and it must be built
with mill duty construction quality to be able to withstand the normal steel mill
operating conditions.

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BASIC OPERATION
Once the hot metal temperature and chemical analaysis of the blast furnace
hot metal are known, a computer charge models determine the optimum
proportions of scrap and hot metal, flux additions, lance height and oxygen
blowing time.
A "heat" begins when the BOF vessel is tilted about 45 degrees towards the
charging aisle and scrap charge (about 10 to 15% of the heat weight) is
dumped from a charging box into the mouth of the cylindrical BOF.
The hot metal is immediately poured directly onto the scrap from a transfer
ladle. Fumes and kish (graphite flakes from the carbon saturated hot metal)
are emitted from the vessel's mouth and collected by the pollution control
system. Charging takes 3-4 minutes.
Then the vessel is rotated back to the vertical position and lime/dolomite
fluxes are dropped onto the charge from overhead bins while the lance is
lowered to a few feet above the bottom of the vessel. The lance is water-
cooled with a multi-hole copper tip(convergence-divergence Laval shaped
nozzle). Through this lance,oxygen of greater than 99.5% purity is blown into
the mix. If the oxygen is lower in purity, nitrogen pick up starts.
As blowing begins, an ear-piercing shriek is heard. This is soon muffled as
silicon from the hot metal is oxidized forming silica, SiO2, which reacts with
the basic fluxes to form a gassy molten slag that envelops the lance. The gas

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is primarily carbon monoxide (CO) from the carbon in the hot metal. The rate
of gas evolution is many times the volume of the vessel and it is common to
see slag slopping over the lip of the vessel, especially if the slag is too viscous.
Blowing continues for a predetermined time based on the metallic charge
chemistry and the melt specification. This is typically 15 to 20 minutes, and
the lance is generally preprogrammed to move to different heights during the
blowing period.
The lance is then raised so that the
vessel can be turned down towards the
charging aisle for sampling and
temperature tests. Furthermore, below
0.2% C, the highly exothermic oxidation
of iron takes place to a variabledegree
along with decarburization. The "drop"
in the flame at the mouth of the vessel
signals low carbon.
In some shops, sublances provide a
temperature-carbon check about two
minutes before the scheduled end of the blow. This information permits an "in
course" correction during the final two minutes and better turn-down
performance. However, operation of sublances is costly, and the required
information is not always obtained due to malfunctioning of the sensors.
Once the heat is ready for tapping and the preheated ladle is positioned in the
ladle car under the furnace, the vessel is tilted towards the tapping aisle, and
steel emerges from the taphole in the upper "cone" section of the vessel. To
minimize slag carryover into the ladle at the end of tapping, various "slag
stoppers" have been designed. These work in conjunction with melter's
eyeballs, which remain the dominantcontrol device. Slag in the ladle results in
phosphorus reversion, retarded desulfurization, and possibly "dirty steel".
Ladle additives are available to reduce the iron oxide level in the slag but
nothing can be done to alter the phosphorus.

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IMPORTANCE OF SLAG IN THE LD PROCESS
Slag has in the LD-process various functions and roles.Primarily, itis
spontaneously formed by the non-volatileoxides resulting in the
oxidation of hot metal minorconstituents and iron (SiO2, MnO, P2O5, TiO2,
VOx, and FeO). In order to flux the impurity oxides to form a lowmelting, fluid
slag, lime and sometimes dolomite (a mixture of CaO and MgO) and, if
necessary, fluorspar (CaF2) are charged into the converter. Secondly, molten
slag is areaction environment for impurity elimination like desulphurization
and dephosphorization, although ladle treatments have diminished the
importance of the LD process in this respect. Slag, when forming an emulsion
with carbon monoxide and metal droplets—slag foaming—obviously plays
some role in post-combustion of primary carbon monoxide to carbon dioxide,
and affects the radiation heat transfer from the ‘hot spot’ formed in the
oxygen jet-iron melt impingement cavity, levelling out the temperature
distribution in the furnace. Foaming slag obviously also decreases dust
generation rate by absorbing some fraction of dust. From the slag formation
point of view, there are two limiting blowing practices:
1. Soft blowing with high lance position without inert gas bottom stirring,
characterized by low iron bath mixing intensity, and
2. Hard blowing with ‘low lance’ and bottom stirring (in combined blown
converters), characterized by more intensive iron bath mixing and
deeper interaction of oxygen jet with the bath.
In the firstcase the interaction of the oxygen jet with the iron bath
is‘superficial’, mass transfer from the bath interior is slowdue to weak mixing,
and iron is in the first place oxidized and slagged.
In the second case interaction between theoxygen jet and the bath, as well as
mass transfer from thebath interior to the superficial layers, is more intensive
andthe minor elements of the bath are in the first placeoxidized. The effects of
blowing practice i.e. soft blowingversus hard blowing, can be summarized as
follows:
• soft blowing increases the slag formation rate
• results in higher FeO content in slag (as well as raises oxygen super-
saturation in the metal)
• favours slag foaming
• promotes dephosphorization at least at a high carbon level

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• increases the oxidation rate of Mn, V, Ti etc.
• increases refractory wear
• raises the risk of slag slopping out of the furnace.
Formation of the Slag: Slag formation starts with the dissolution of oxygen in
iron melt and simultaneous oxidation of iron and minor bath constituents in
the oxygen jet impact zone. As the bathtemperature in the impact zone is very
high, over 2000°C, iron can dissolve a great amount of oxygen (up to 1 wt%).
Iron oxide forms and the primary oxidation zone and high oxygen iron
penetrate the bath and meet ‘fresh’ iron melt with higher contents of carbon
and other minor bath constituents oxidizing them. Part of the primary reaction
products are splashed into the slag and furnace atmosphere. Iron oxide and
other
nonvolatile oxidation products (SiO2,MnO, P2O5, TiO2, VOx etc.) mix with
existing slag and more lime (doloma) is dissolved into the molten slag. Slag is,
accordingly, formed by a complex chain of reactions. The overall slag forming
can be presented by the following set of reactions.
These reactions are followed by secondary oxidation-reduction reactions,
especially by decarburization takingplaceon the surfaceof metal droplets
circulating in the slag.

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In the start-up period of a converter blow, when the bath temperature is low,
slag might be saturated by dicalcium silicate, but with theprogress of hot metal
oxidation the slag composition departs from the dicalcium silicate ‘nose’
returning in the later stage of the blow back to it and passing it to the
tricalcium silicate saturation or even lime saturation range (seeFigure 3). The
evaluation of the slag path passing the high temperature liquidus surfaces such
as the dicalcium silicate nose or liquidus surfaces of the tricalcium silicate or
lime and corresponding precipitation of solid phases from the melt, is
somewhatobscured by the fact that slags are multicomponent phases and the
slag temperatures have been reported to exceed, even by severalhundred
degrees, the averagetemperature of the iron bath.

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THE ADDITION OF IRON ORE
IRON ORE ADDITION
Scrap, slag and iron ore addition are made to the furnacefor a variety of
reasons
 To adjustthe liquid the metal temperature
 To adjustthe liquid metal composition
 To change the slag composition and thereby its properties
An optimum addition of iron ore is essential because:
If the addition is more than required, a heavy cooling can take place. one ton
of extra iron ore reduces the temp by 30 deg c
 Slag fe can increaseleading to liquid slag
 Iron oremay not go in to the metal
If the addition are less than required, the temp may shootup and go much
above the aim temp leading to the vessel damage
 The chance of rephos increases after the steel is made and from the
carrying over slag phos can again go in to the metal
 Slag Fe decreases and thick slag can be found
Depends on
1) Si content
2) Scrap added
3)HMtemperature
4) Dolomite addition
5) Vessel condition
Increases in
1) HM weight
2) HM Temperature
3) Si content
Will affect
1) Turndown
temperature
2) Turndown P
3) Slag condition
(viscosity)

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BLOWPRACTICE
 The blow practice depend upon following parameter
 Initial vesselcondition (initial temp)
 Retain slag (slag wash)
 Hot metal temp and composition
 Lime ,oreand raw dolomite addition
 Number of TBMs open (stirring)
 Lace height and lance moment
 Bath ;height control to adjustblow and slag formation
 Hard blow make the slag dry and cause phosphorus reversal.
 Two softblow will increaseFe content in slag.
AT LD #1 the operators follow a basic procedureduring the blow as mention as
under:
 Lance hood and skirtis checked for any water leakage
 The model is run by the controller giving remaining slag, aim temp.
 Then the “PREP” button and Blow startbutton is pressed after
checking all the inter locks.
 Then the ignition switch is pressed which starts the timer and oxygen
counting.
 Now the skirtis lowered for :
 Positivepressureatthe vessel mouth.
 To stop excessiveingress of air
 All lime and dolomite added with in first 3 min.
 Now the both slopping and drying condition of slag can be watch
which there basically governed by the sound by the vesselmakes.
 Lance height and venture is maintained and adjusted automatically
 Iron oreis added as per the model or previous heat experienced.
Higher addition may lead to slopping.
 The blow is then terminated
 The vessel is purged for 30 sec for homogenisation .
 The sample and temp is taken.
 The slag is analysed by controller based on its thickness .
 Some slag is retained for next heat and for slag coating

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TURNDOWN CONDITIONS
DEPHOSPHORISATION
 Out of all these, removalof phosphorus from the steel is of prime
importance and should be done with care so as to avoid rephos from the
slag to the steel
 Best condition from the phosphorus removal from the liquid steel from
a thermodynamic view point can be summarised as a highly basic, lime –
rich slag.
 A satisfactorily high level of oxidation of iron .(if it is much more than
Ca0 wt% will decrease)
 2 p+5feo=p2o5=5fe
 Lower possibletemp
 The lowest possibleamount of undissolved freelime in slag. (this is
because of low kinetics)
END POINTCARBONABD TEMPERATURE CONTROLL
GOOD
TURNDOWN
REQUIRESOPTIMUM BASICITY
(3 – 3.4)
GOOD AMOUNT OF
SLAG Fe (15-18%)
TURNDOWN TEMPERATURE WITHIN A GIVEN RANGE (1640 – 1680 deg
C)
PHOSPHOUS REMOVAL

31. 31
Following parameter are employed to evaluate the efficency of end point
carbon and temp control:
 Hit rate: reportas %heats wherethe heat point C & T are within
specified tolerance bands.
 Standard deviation; from the aim value of C&T.
 Percentage of reblows requireds to arriveat aimed end points (non
reblows is ideal)

32. 32
REACTION IN THE VESSEL
OXYGENPICK UP BY THE METAL:
O2 (g)=2O
(FeO)=Fe+ o
Fe2O3 =2FeO + O
Co2(g) = Co(g) + O
Oxidation of element in metal:
C + O =Co(g)
Fe + O =(FeO)
Si +2O =Si
Mn +O=(MnO)
2P+5O=(P2O5)
OXIDATIONOF COMPOUND INTHESLAG
2(FeO)+1/2O2(g)=(Fe2O3)
2(FeO)+CO2(g)=Fe2O3)+CO
FLUX REACTION
MgO(s)=(MgO)
CaO(s)=(CaO)
GAS REACTION
CO(g)+1/2o2(g)=CO2

33. 33

34. 34
BLOWING CONTROL AND TURNDOWN
The primary objective of refining or blowing control is to oxidise the metalloid
impurities in the chargeand to form a basic slag as rapidly as possible in order
to protect the lining and to permit adequate sulphur and phosphorus removal.
the controlof the refining cycle can be attained by proper combination of
lance practice , flux practice and oxygen flow rate. It is essential to develop a
refining strategy which form an early basic slag and maximises carbon removal
rates withoutadversely affecting the lime solution and sulphur and
phosphorus removaland which minimise slopping and ejection from the vessel
during the blow. Last but mostimportant,the temp at turndown should be
optimum.
TURNDOWN CONTROL
The time required between firstturndown and start tap is an importantfactor
in overall productivity of a BOF shop. Heat require for large correction for temp
or analysis will significantly productivity last decay has seen mean very
development aimed at improving turndown or end point control .
The control of end point condition should start with a good static charge
control practice which requires both good thermodynamic model and close
attendance to the accuracy of the input to the model in turn of weight ,temp
and chemical analysis of the charge materials. Every effect should me to
employ a consistence scrap charge on all heats in term of the relative amount
of each type of scrap. A well standardised blowing and flux addition practice
should to be used on each type of heat in order to reduce the heat to heat
variability in decarburisation and slag development kinetics consistent
application of the above criteria will performance of each of the dynamic end
point methods

35. 35
CORRECTION OF TEMPERATURE AND ANALYSES
IN TATA Steel correction of temperature is done by adding scrap to hot metal.
Scrap addition is done as per the hot metal availability, that is we consider 5
ton hot metal we add 10 ton of scrap it. The maximum scrap addition will be
up to 20ton (limited the size of the scrap charging chute/pan and
thermodynamic heat balancing)
If the slag is thick as is the case with the use of large percentage of dolomite
lime or where the FeO is low , as high carbon heat, the limestone chips are less
effective. Occasionally even iron ore will land on top of every thick slag and
remain there without reaction.
The furnace may be rocked to promote a more rapid reaction with the coolant.
Reblowing with the lance raised can shape up the slag, and accelerate cooling
with limestone when slag are very thick.
The use of limestone and particularly iron ore for cooling can result in further
bath decarburisation particularly on higher carbon heats.
When coolant scrap is added the slag is usually penetrated readily and the
temperature drop obtained is more predictable. However, when large
amounts of scrap are used, sufficient time must be allowed for the scrap to
melt before the heat is tapped
REBLOW
If the bath temperature is too cold (less than 1630 deg C) the heat will
normally be reblown immediately without waiting for the analysis of the
turndown sample. Some shop do not even sample the bath if it is cold and
requires a reblow for temperature .for a 200 ton BOF heat approximately
15000 SCF of re blow oxygen will raise the bath temperature by 30⁰F
If the turndown bath analysis for carbon, sulphur, phosphorus or manganeseis
above the tapping specification for the scheduled grade, correctivereblows

36. 36
can normally be used to reduce the analysis to the required specification. The
following reblow practice are used for these corrections
Type of reblow Lance height Vessel addition
For temperature Low None
For carbon reduction Low None
For manganese
reduction
High None
For phosphorus
reduction
High Iron ore
For sulphur reduction High Lime and fluorspar

37. 37
THE AUTOMATION MODEL
The static model used in BOF is based on pre-set calculation which are based
on the input mechanismof parameter data, its processing in accordancewith a
well defined chemistry and the overall material and heat balance process.
The BOF model used at LD#1 is a static model and takes into accountvarious
parameters/variables for calculating the addition require for each single blow.
The relationship between various parameters are customised and set in
accordancewith pre-existing literature.
MODEL WORKS IN FOLLOWING FASHION
INPUT OFDATA FROMTHE SYSTEM
PROCESSINGIT IN ACCORDANCEWITH CHEMICAL AND HEAT BALANCE
EQUATION
PRECDICTINGAN OUTPUT ON THE BASISOFTHE INPUT DATA

38. 38
INPUTS TO STATIC BOF MODEL ATLD
OUTPUT TO STATIC MODEL AT LD 1
BOF MODEL
HOT METAL
ANALYSIS
HOT METAL
WEIGHT
HOT METAL
TEMPERATURE
SCRAP RETAINED
SLAG
ORE
LIME
LIMESTONE
DOLOMITE
OXYGEN
CAST NO
RET STEEL
GRADE
CONVERTERNO
LADLE NO
PAN NO
BATH HEIGHT
BLOWER
AIM
ANALYSIS
AIMWt
AIMTemp
BOF model
PREDICTED
VALUE
1.ORE
2.LIME
3.LIMESTONE
4.DOLOMITE
5.OXYGEN
PREDICTED VALUES
EOB SLAG ANALYSIS
PREDICTED VALUES
STEEL ANALYSIS

39. 39
STATIC MODELS CAN BEUSED TO CALCULATE
a. Optimum chargemix,
b. Requirement of addition during blowing
c. Total oxygen required.
d. Time of blow.
THEY CANNOT PREDICT
a. blowing parameters like oxygen flow rate .
b. lance height or bath height.
c. Any parameter as a function of time.
The soundness of the prediction depends on severalfactors
a. Accuracy chargecontrol mode.
b. Accuracy of input to the computer system.
c. Consistency of steelmaking practices.
d. Reliability of computersystem and its use.

40. 40
For making such estimate dynamic models a required. The presented model
can be used for semi dynamic control taking the help of sub lance
measurements. However by their very nature static models are not able to
predict many variation as mentioned above.
Dynamic model contains all the feature of static models and in addition having
terms for reaction kinetic and process dynamic. The possibleapproaches
include the following.
 Instantaneou sequilibria amongstthe reacting phasemay be assumed
and the process can be treated as being thermodynamically reversible.
 Reaction are assumed to be mass transfer control.
 After SI oxidation, the major reaction are those of iron and carbon.in
the caseof fully dynamic control ,exit gas will be help.

41. 41
FLAWS INTHE PRESENT AUTOMATIONMODEL
 The BOF model fails if all the input are not given; although the
main inputs are HMtemp, weight, scrap, and si.
 The retained slag input is some fixed value of 0,2,5and 10 tons
,etc and cannot be altered as per requirements.
 Although the model take care of history but still feedback given
that can be improved.
 Operators deviate greatly from the models.
 The model is unable to rectify these changes as it mostly follow
strict theoretical calculation.

42. 42
PROBLEMS FACED IN LD 1
 Fastproductivity and slow demand
 Over capacity in steel
 Market distortion
 Sticking of ore
 Slurry formation
 Non uniformdischargeof lump formation
 Delay in shooting time
 Problems in steel making in rainy season
In rainy season the raw materials such as lime, iron ore, scrap, dolomite
contain moisture presencewhich affect steel making.
WET RAWMATERIAL
LIME may be used for sulphur and phosphorus removalatthis stage as well.
Most importantly, quicklime is typically added to the mixture in the
steelmaking furnaceafter the beginning of the oxygen “blow” whereit reacts
with impurities (primarily silica and phosphorus) to form a slag which is later
removed.lime plays a key role in fine tuning steel chemistry, lowering oxygen
content, removal of impurities such as sulphur and reduction in inclusions
trapped by the basic slag.
Lime is used in these secondary processes, LadleMetallurgical Furnace, (LMF)
and Vacuum Degassing. moisturecontent in the lime make loss on ignition
which will lead to higher lime consumption
CaO+H2OCaOH2+HEAT
IRONORE:- Iron ores are rocks and minerals from which metallic iron can be
economically extracted. The ores are usually rich in iron oxides and vary in

43. 43
colour from dark grey, brightyellow, or deep purple to rusty red. The iron itself
is usually found in the formof magnetite (Fe. 3O. 4, 72.4% Fe), hematite
(Fe2O3)when iron ore having moisture content is used, temperature
malfunction will carry out in the vesselfeeder jamming is another problem
facing with moisturecontent
Dolomiteis an anhydrous carbonatemineralcomposed
of calcium magnesium carbonate, ideally CaMg(CO3)2. Theterm is also used
for a sedimentary carbonaterock composed mostly of the mineral dolomite.
An alternative name sometimes used for the dolomitic rock type is dolostone.
Dolomite having moisturecontent will have a problem that temperature
malfunction will take place in the vessel
SCRAP:- Scrap consists of recyclable materials left over from product
manufacturing and consumption, such as parts of vehicles, building supplies,
and surplus materials. Unlike waste, scrap has monetary value, especially
recovered metals, and non-metallic materials are also recovered for recycling
when we use wet scrap for steel making it will leave to explosion

44. 44
AIM OF THE PROJECT
Effect of moisturecontent on turndown temperature
The study and analysis of moisturepresent in ironoreand dolomite.
SAMPLESTUDY AND MOISTURETESTING
INTATA steel moisturepresence is noted by the normalmethod of moisture
testing. RAC lab 3 is mentioned for the operation. the given samples are
weighted and heated in furnace which having a heat rangeof 150-200 deg c
for 15- 30 min. after that the heated sample is taken out and weighted again
and now we can find the moisture content by substracting by intial weight and
final weight
Moisture% =( intial weight- final weight) *100
RESULT OF SAMPLETESTING
SAMPLES MOISTUREOF IRON
ORE
MOISTUREOF
DOLOMITE
SAMPLE-1 4.75% 2.86%
SAMPLE-2 5.56% 2.62%
SAMPLE-3 3.25% 2.32%
SAMPLE-4 3.0% 1.9%
SAMPLE-5 4.28% 2.44%
Average moisture percentageof ironore =5%
We have found that moisture percentageof dolomite is very small sowe
neglectedthe moisturepercentage of dolomite

45. 45
IRON ORE HAVING 5% MOISTURE
Calculationof corresponding dropintemperature of steel due tothe
additional presence of moisture in Fe2O3 addedduring the blow
Tonnage of FeO =10.577
%H2O in FeO =5%
Tonnage of liquid steel in the vessel=160
Temperature of Flue gas at Vesselmouth during blowing =650⁰C
Room temperature =30⁰C
Specific heat of water= 4.185 J/g/K
Specific heat of steam (approx. from 100deg C to 650 deg C) = 2.675
Specific heat capacity of liquid steel at 1600deg C =0.82
Latent heat of vapourisation =2257
Tonnage of H2O in FeO =0.52885
Heat required to heat H2O from room temp to 100 deg c =154.9266075
Heat required to convert H2O to H2O at 100degc =1193.61445
Heat required to heat steam from 100deg c to 650 degC=778.0705625
Total heat extracted by moisture in FeO=2126.61162
Corresponding dropin temperature of liquidsteelat 1600⁰c =16⁰c

46. 46
EFFECT ON STEEL MAKING (∆H +∆H(MOISTURE))
3Fe2O3 + CO(g) 2Fe3O4 +CO2 (S) ---------------------------------------------1
Fe2O4 + CO(g)3FeO (s)+CO2(g) ---------------------------------------------2
FeO(S)FeO(SLAG) ---------------------------------------------------------------3
When we add 10 ton Fe2O3 heat is extracted
1) Raise in temp
2) Enthalpy change
If weadd 10 ton dry Feo3 what is absolute temp drop in liquid steel
160ton * Cp *[Xa – 1637] = 1+2
If weadd 10 ton moistFe2O3 whatis the absolute temp drop in liquid steel
160 ton * Cp * [Xb – 1637] =1 + 2 + (Mw*Cp*∆t) + (Mw *latent heat) +
(Mw* Cp*(600-100))
3Fe2o3 + CO Fe3O4 + CO2
2Fe3O4 +2CO  6 FeO +3CO2
3Fe2O3 + 3CO  6FeO +3CO2
Fe2O3 +CO 2FeO + CO2
By mole fraction method we can say that enthalpy formation
Fe2O3 = 814.1
CO = 114.4
2FeO =2* 263.7

47. 47
CO2 =395.3 KJ/mol
Therefore wesay that the equation,
Fe2O3 + CO  2FeO + CO2
=5.8 KJ/mol
1 mol Fe2O3= 56 * 2 + 16 * 3
=160
1 tonne of Fe2O3 = 36,250 KJ/tonne
FeO(S)FeO(SLAG )
FeO(S)FeO(l)
By mole fraction we can say that enthalpy formation
FeO(S) =263.7
FeO(l)=225.6
Per mole of FeO= 38.1kj/mol
FeO =56+16 =72 gm
Per ton of FeO = 38.1*2/0.000072
=1058333KJ
FeO FeO SLAG
Per ton at Fe2O3 HEAT extracted
=1*Cp fe2o3 [1637-3] +1*[1058333+36250]KJ
=1*0.8864*1000[1637-30] +[1094583]
=1424444.8+1094583
=2519027.8KJ
For 10 ton Fe2O3

48. 48
Q =25190278KJ
Original temp of steel =T⁰s
160*1000*0.82*(TS-1637)=25190278
T⁰s = 1637+192
For 9.5Fe2O3+0.5H2O
Q Fe 2O3=2519027.8*9.5=23730764kj
For 0.5ton of H20
Q H2O=2010600 KJ (thepredetermine value of heat extracted by the moisture
in FeO)
TOTAL Q=25941364
(T⁰S=1637+197.7 ⁰c)
191
192
193
194
195
196
197
198
199
200
0% 1% 2% 3% 4% 5% 6% 7%
Temparturedrop,degC
Moisture in Iron Ore, %
Drop in temperature of 160t of liquid steel for addition of 10t Iron ore
with different moisture content

49. 49
KEY LEARNING OUTCOMES
The internship has provided good learning outcomes which included
 Practical understanding of corporateenvironment
 Importanceof punctuality and time management
 Enhanced inter personalskills and learnt how to deal with seniors and
colleagues
 Learnt team work
 Learnt the working operation
 Learnt basic process carry out
 Try to find effect of moisture