Mid Term Project Presentation

1
MiD Term PROJECT TopicSTUDIES ON ENZYME MIMETIC
CATALYSIS OF FUNCTIONAL Ceramics ANDReactions of
BLAST FURNACE

• CYAN MUKHERJEE
• MTECH CHEMICAL Engineering
• Indian Institute of Technology Kharagpur
• 22CH60R06
• Guide PROF PARAG DESHPANDE

2
Different zones of Reaction Furnace

• Blast furnace sections divided into following
  zones according to reaction
• Slack reactions
• Bosh reactions
• Tuyere reactions
• Hearth reactions

3
Fig.1.1 Diagram showing different sections of
blast furnace 1.Stack 2.Bosh 3.Tuyere 4.Hearth
4
CHARACTERISTIC Features of Reaction zones
Happening in blast furnace

Tuyere reaction zones

Reduction of ore completed Oxides and metals partially melted down,all endothermic reactions favoured by higher T and move to hotter sections
Molten metal and slag collected in the hearth
Reaction zones
Salient Features
Chemical reactions
Important zone for coal gasification
Exothermic chemical reactions taking place within
the furnace and from the sensible heat in the
pre-heated blast Heat
produced from combustion of the coke
C(s)O2CO2(g) Zone A C(s)CO22CO
Zone B Boudouard reaction 2C(s)O22COO
verall reaction
Heating of ores and their reduction due to direct
contact with ascending hot gases Fe2O3
Fe3O4 FeO Fe
Slack reaction zones
3Fe2O3(s)CO2Fe3O4(s)CO2 xFe3O4(s)xCO?3Fe
xOxCO2 FexO CO?xFe(s)CO2
(FeO)CFeCO (SiO2)2COSi2CO2 P2O5
5CO2P5CO2 MnOCMnCO SiO22CSi2COP2O55C
2P5CO
Bosh Reaction zones
(MnO)CMnCO (SiO2)CSiCO FeS(FeS)
FeOCaOFeSCaO FeSCaOCFeCaSCO
Hearth Reaction zones
Slag floated on top of the molten metal layer
5
TUYERE RACEWaY ZONE AND TUYERE FLAME TEMPERATURE

• Zone created by voidage due to consumption of
  coke in front of tuyeres leading to carbon
  monoxide formation in presence of air by reaction
  with oxygen in Blast furnace known as Tuyere
  raceway zone(Fig.1.2)
• Two regionszone A, the gas phase,(primarily of
  O2, CO2 and N2)
• Zone B,gaseous phase consisting CO2, CO and N2
• For rapid heat transfer of raceaway zone, the
  combustion zone temperature maintained at a much
  higher temperature normally in the range of
  18002000 C,known as the tuyere flame
  temperature

Fig.1.2. Tuyere raceway zone
6
ADIABATIC RACEWAY TEMPERATURE(RAFT)

• Theoretically estimated temperature in the
  raceway zone where no heat loss known as
  Adiabatic Raceway Temperature (RAFT) in the range
  of 20002300 C
• RAFT controlled by Blast parameters like
• Temperature
• Oxygen content
• Humidity contentFuel injectant rate

7
Modern concept of Blast furnace Process

• Blast furnace actually the counter current
  reactor for heat and mass exchanges between the
  gaseous and solid phases
• Blast furnace having three main functions
• Chemical reactor for iron ore reduction
• Melter to melt metal and slag
• Combustion chamber for production of large amount
  of heat and reducing gases

8
Modern concept of Blast furnace Process(CONTD)

• Five zones as per the movement of materials from
  solid to liquid phase
• Lumpy or granular zone Softening and melting zone
  Dripping (or dropping) zone
• Hearth zone

Fig 2.1. X) Zones of BF (1 lumpy or granular
zone, 2 softening and melting zone, 3 dripping
(or dropping) zone, 4raceway zone and 5 hearth
zone) (Y) vertical cross section of zones within
BF
9
Characteristic FEATURES oF Blast furnace Zones

• Lumpy or granular zone
• Below 600C Pre heating and pre-reduction
• 600ltTlt950,indirect reduction of Iron oxide by
  CO and H2,Calcination of limestone
• Dripping zone-Area of presence of coke, liquid
  iron and slag
• Dead man zoneStable pile of solid coke parties
  in the Hearth of furnace
• Final stage of iron oxide reduction.Coke not
  taking part in any reaction

10
Characteristic FEATURES oF Blast furnace
Zones(CONTD)

• Raceway Zone Conversion of Blast,injectants and
  coke into hot reducing gases and transferred to
  the central part of the furnaceGasification of
  coke creating void.This is illustrated in the
  Fig.2.1.
• Hearth zone Characteristic of passing of metal
  droplets through slag/coke layer

11
FUNCTIONs of Blast furnace

• Reduction of iron oxides observed
• Heat transfer from hot gas to solids
• Utilization of Proper gas

12
Effect Of alloying elements on the solubility of
carbon in liquid iron
Fig.2.2.Effect of alloying elements on the
solubility of carbon in liquid iron
13
EFFECT of Allowing elements On the solubility Of
carbon in liquid iron(COnTD)

• Hot metal containing 3.54.0 C comparatively
  less than maximum carbon(6.67) present in FeC
  phase diagram due to the presence of other
  elements (e.g. Si, P, S, etc.)decreasing its
  solubility enhancements of its activity. This
  type of carbon dissolution in Hearth Reaction is
  explained in Fig.2.2.

14
Tabular Form of Enthalpy formed in THE REACTION
Zones of Blast furnace



Highly endothermic Endothermic Endothermic 153.89 KJ/mol of CO



C(s)H2OCOH2 Endothermic 135.14 KJ/mol of C
Nature of Reaction
Chemical reactions
?H0KJ/mol at 298K

• C(s)O2CO2(g)
• C(s)CO22CO

• Strongly exothermic
• Endothermic

• -394.13 KJ/mol of C
• 170.7 KJ/mol of C

• Exothermic
• Endothermic

• -52.43 KJ/mol of CO
• 40.46 KJ/mol of CO

3Fe2O3(s)CO2Fe3O4(s)CO2 xFe3O4(s)xCO?3Fe
xOxCO2
FeO(s)C(s)Fe(s)CO SiO22COSi2CO2 P2O55
CO2P5CO2

• 153.35 KJ/mol of CO
• 34.73 KJ/mol of CO

• Endothermic
• Endothermic

• MnOCOMnCO2
• MnOC(s)MnCO

• 102.31 KJ/mol of CO
• 273.52 KJ/mol of C

• SiO22C(s)Si2CO
• P2O55C(s)2P5CO

• Endothermic
• Endothermic

• 324.05 KJ/mol of C
• 205.43 KJ/mol of C

• CaCO3(s)CaO(s)CO2
• C(s)CO22CO

• 161.3 KJ/mol
• -111.715 KJ/mol of C

• Endothermic
• Exothermic

FexO CO?xFe(s)CO2
Exothermic
-18.54 KJ/mol of CO
15
FREE ENERGY OF FORMATION OF OXIDES REDUCABLE BY
BLAST FURNACE GAS

• Oxides such as MnO,SiO2,P2O5 observed to be
  easily reducable by Blast Furnace Gas(i.e.CO) at
  1300-1400C as displayed in Fig 2.3.
• Favoured by a high temperature and proceed in the
  hotter zones of the furnace
• Iron and phosphorous lines, on the Ellingham
  diagram (Fig. 3.3) so close to each other that
  entire phosphorus in the charged materials
  getting reduced along with iron in the blast
  furnace
• Above 1200 C, phosphorus significantly in
  vapour state and outer layer of iron absorbing P
  as well as Mn and Si
• SiO2,MnO and FeO dissolved in each other for
  producing a highly acidic slag rich in silica at
  upper bosh region

Fig.2.3.Diagram showing free energy of formation
of some oxides
16
Direct and indirect reduction

• Degree of direct reduction more than the optimum
  value, so any vital decrease in the degree of
  direct reduction leading to improvement of coke
  rate
• Reduction of wusite(FeO) by CO followed by carbon
  gasification reaction, these reactions known as
  indirect reduction
• FeO(s)COFe(s)CO2 ?H0-18.54 KJ/mol of
  CO298K
• C(s)CO22CO ?H085.35 KJ/mol of CO298K
• Solid wusite encountering with carbon, direct
  reduction taking place
• FeO(s)C(s)Fe(s)CO ?H0151.25 KJ/mol of
  CO298K
• Rate of direct reduction similar to that of
  solution loss reaction through above previous
  reactions

17
REFERENCES

• C. Bodsworth, Physical Chemistry of Iron and
  Steel Manufacture (CBS Publishers Distributors,
  Delhi, 1988)
• W.K. Lu, in Proceedings of International
  Symposium on BF Ironmaking, Jamshedpur, India,
  Nov 1985
• R.D. Walker, Modern Ironmaking Methods (The
  Institute of Metals, London, 1986)
• S. Kundu et al., IIM Metal News 19(5), 18 (2016)
  T. Kamijou, M. Shimizu, PC combustion in blast
  furnace, in Advanced Pulverized Coal Injection
  Technology and Blast Furnace Operation, vol. 1
  (Pergamon, Amsterdam, The Netherlands, 2000), p.
  63 M. Geerdes, H. Toxopeus, C. Vliet, Modern Blast
  Furnace Ironmaking, 2nd edn. (IOS Press BV,
  Amsterdam,Netherlands, 2009)

18
THANK YOU