Presentation final 2.0

Inox Group #3Mohammed Abu SharkhSpencer BrennanSaikat ChandaMichael Garibaldi

Production of Stainless SteelDesign Project II: Final Presentation

April 23rd, 2014

Stainless Steel Production 2

Mandate & Scope• Mandate:

• 2 million tonnes of stainless steel slabs• 600,000 tonnes of high carbon ferrochromium from group 1 and

group 2 • Desired stainless steel compositions: maximum 0.08wt% carbon,

18wt% chromium and 8wt% nickel

• Project scope:• High carbon ferrochromium, ferronickel, ferrosilicon, iron

ore and steel scrap are the major raw materials• Production of stainless steel slabs with dimensions 10 m x

1 m x 0.25 m• Recycle and treatment of off-gas


Process Description 1.Midrex Direct Iron Reduction

• Gas-based iron ore reduction• Syngas production

2.Electric Arc Furnace• Decrease carbon and gangue material content

3.Argon Oxygen Decarburizer• Decrease carbon content• Increase chromium content• Nickel addition

4.Continuous Casting• Cooling and compression casting of metal slabs


Block Flow Diagram

Midrex Process

Electric Arc

Furnace

Argon Oxygen

Decarburizer

Continuous Casting

Iron Ore, Water, Natural gas, air,

CO from group#2

DRI SteelStainless

Steel

Steel Scrap , Lime, Atmospheric Air

Oxygen, Argon, HCFeCr, FeNi40, Flux(FeSi + CaO) Cooling Water, Process Water,

Atmospheric Air

Off-Gas

Slag

Effluent To waste water

Air

Stainless Steel Slabs

Off-Gas


Midrex Process: Overview• Process Objectives:

• Decrease oxygen Wt% in iron ores from 30% 3%• DRI containing 1.6 Wt% Carbon• Produce 1 million tonnes per annum direct

reduced iron (DRI)• Hot charged to EAF at 650oC

• Iron ore pellets provide 65% of the total iron content of stainless steel

• Iron ore Pellets

DRI Source: Siemens.com, 2014


Midrex Process: Shaft Furnace & Steam Reformer

• 2 main units:• Shaft furnace for iron reduction:

• Fe2O3 + 3H2 2Fe + 3H2O• Fe2O3 + 3CO 2Fe + 3CO2

• 2 hours residence time

• Steam reformer for syngas production:• CH4 + H2O CO + 3H2

• CH4 + CO2 2CO + 2H2

• Combustion of natural gas used to heat feed reactants to 900oC and for endothermic reactions

Source: ThyssenKrupp, 2014


Midrex Process: Reformer PFD


Midrex Process: Shaft Furnace PFD


Midrex Process OverviewInput

Iron Ores (tons/yr) 1.4 million

Syngas (tons/yr) 890,000

Output DRI (tons/yr) 1 millionDimensions

Shaft Furnace total Height (meters) 26.7

Shaft Furnace Internal Diameter

(meters)6.5

# of Reformer Tubes 378

Power Requirments

Shaft Furnace (MW) 75

Reformer (MW) 102

Costs Dollars (US $)

CAPEX 85,056,000

OPEX 235,072,000

OPEX (per tonne Stainless Steel) 118.00


Electric Arc Furnace: Overview• Process Objectives:

• Reduce Fe• Fe3C, FeO → Fe

• Oxidize C • 1.6 wt% to 0.99 wt%

• Remove oxides• SiO2, MgO, P2O5, TiO2, Na2O

REACTANTS PRODUCTS

1 Fe3C 3 Fe, 1 C

1 FeS + 1 CaO 1 FeO + 1 CaS

1 FeO + 1 C 1 Fe + 1 CO

Source: Midrex Technologies, 2013


Electric Arc Furnace: Overview


Electric Arc Furnace: PFD


Electric Arc Furnace: OverviewINPUT OUTPUT

DRI Lime Steel Scrap

Air

wt% wt% wt% wt%

Mass Rate

Tonnes/year

1,016,174 60,000 150,000 51,141

Fe 68.65 0 96.85 0

Fe3C 23.92 0 0 0

FeO 3.00 0.61 0 0

C 0 0 1.35 0

SiO2 2.29 2.58 0.06 0

FeS 0.0085 0 0 0

CaO 0.79 94.5 0 0

O2 0 0 0 21

N2 0 0 0 79

Steel Slag Off-Gas

wt% wt% wt%

Mass Rate

Tonnes/year 1,094,550 112,125 70,640

Fe 98.93 0 0

FeO 0 6.27 10.89

C 0.99 0 0

SiO2 0.08 20.41 0.39

CO 0 0 26.89

MgO 0 4.49 0.41

CaO 0 57.09 1.00

Units Value

Power MWh 186

Cooling Requirements MJ/h 322

CAPEX $ 83,704,400

OPEX $/tonne steel 89


Argon Oxygen Decarburizer: Process Overview

• Process Objective: • Reduce the Carbon content from

1 to 0.08 wt%• Add Nickel and Chromium to the

final Stainless Steel Slabs

• Operating temperature:• 1600 - 1800 ⁰C

• Regain iron and chromium from slag

Source: SMS-Demag


Argon Oxygen Decarburizer• Main Reactions:

• C + ½ O2 → CO• Si + O2 → SiO2

• 2Fe + O2 → FeO• 2Cr + 3/2O2 → Cr2O3

• FeSi + 2FeO → 3Fe + SiO2

• Cr2O3 + 3/2FeSi →2Cr + 3/2SiO2 + 3/2Fe

• Oxygen : Argon = 3:1 (@ the beginning)

• Oxygen : Argon = 1:3 (@ the end)• Argon added to prevent unwanted

oxidation• Process time: 1 hour Source: MSTS


Argon Oxygen Decarburizer: PFD #1


Argon Oxygen Decarburizer: PFD #2


Argon Oxygen Decarburizer: Overview

Input

Compounds Value

Steel (From EAF) (t/annum) 1,094,500

High Carbon FerroChrome (HCFeCr )

(t/annum) 600,000

Ferronickel (FeNi40) (t/annum) 400,000

Oxygen (m3/annum) 47,663,000

Argon (m3/annum) 106,673,000

Flux (FeSi + CaO) (t/annum) 200,900

Output

Compounds ValueStainless Steel

(t/annum) 2,020,000

Off-Gas (t/annum) 278,000

Slag (t/annum) 251,000

Significant Items ValueEnergy Requirement (MWh) 0.2

CAPEX ($US) 290,764,000OPEX ($US per tonne

Stainless Steel) 1684.00


Continuous Casting

• Process objective: • molten stainless steel

solidification into a continuous strand where it is cut into slabs

• Storage of stainless steel in tundishes converts entire batch process to continuous

• Two casting machines in operation due to casting speed restriction

Source: http://www.isam-ag.com/casting


Continuous Casting: Casting


Continuous Casting: Flux & Molten Addition


Continuous Casting: Water Cooling


Continuous Casting: Blowing + Inventory


Continuous Casting: Cooling Overview


Overall Top View Plant layout


Overall Side View Plant Layout


Environmental Evaluation• 85% of CO provided from group 2 and off-gases• 15% of total CO2 is recycled for syngas production• 0.8 tonnes of CO2 per ton DRI• Required bag house to meet particulate matter emission

limit

Allowable

(mg/m3 per 8 hours)

Allowable (kg/day)

Emitted (kg/day)

CO 55 1294 0

SO2 13 306 0.06

P2O5 1 24 0.20

SiO2 30 706 9.92

PM 15 353 504

Flow rate (m3/day) 7839513


Control Philosophy• Ensures the timely production of 2 million tonnes of

stainless steel per annum safely from a batch to continuous process

• Semi-batch process operating via tapping until the ladle is discharged into the tundish

• All vital supporting operating units have redundancies

• Controllers are wired to the central control room

• Alarms are installed at sensitive measurement sites


Continuous Casting: Tundish Discharge Control


Annual Economic Breakdown by Group

• The majority of the revenue comes from selling stainless steel slabs

• Procurement of ferronickel drives the operating expenditures of Group 3 up


Economic Analysis• Depreciation (declining balance) of all assets - 10% per annum • Corporate tax rate - 40%• The investment - 100% equity • Cost of capital -10%• Non-integrated taxation method with depreciation losses not allowed• Total capital investment of the plant equally split over the first three

years of pre-production• Total project lifespan - 20 years

Presentation final 2.0

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