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Nordic Recycling Day V, February 3rd, 2010, Oulu University

The Importance of Process Integration

in the Iron and Steel industry

Presentation by Lawrence Hooey

Swerea MEFOS, Luleå, Sweden

Nordic Recycling Day V, February 3rd, 2010, Oulu University

Content

Swerea MEFOS

PRISMA

Process Integration

Tools for modelling

Modelling cases

- how to reduce CO2-emissions

in a steelplant

- scrap charging to BOF

- oxygen blast furnace

- recycling of residual products

Conclusions

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Swerea MEFOS

Metallurgical Research Institute

Performs joint research for Member Companies

Performs contract research for clients worldwide

Pilot plant facilities for iron & steel making

Hosting LKAB Experimental Blast Furnace

Pyro metallurgy

Heating and metalworking

LKAB’s Experimental BF

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Nordic Recycling Day V, February 3rd, 2010, Oulu University

PRISMA

Centre for Process Integration in Steelmaking

Institute Excellence Centres

” to bring together industry, institutes and universities in research of international standing in well defined, new areas to the benefit of the Swedish industry”

Joint activities at a research institute

Involvement of personnel from industry and university on a

significant scale

Much of the work done by senior researchers

Doctoral work is included to, among other things, create sustainable

relationships between research institutes, universities, and the industry

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Applies Process Integration in the ore processing, ironmaking and steelmaking processes,

Builds a solid foundation of techniques and tools, by the pursuit of implementing projects in collaboration with industrial partners,

Have a focus on effective use of resources with a system perspective, where resources can be energy, materials, environment, costs, etc.,

Based primarily on the established process knowledge and is a complement to the traditional process development.

The PRISMA research programme

8 partners, 4 programme areas

Method development

Method adaption

TEMA 1:

Framtida produktionssystem

TEMA 2:Optimal råmaterialdesign

TEMA 3: Effektiva & uthålliga energisystem

TEMA 4: Analys av restprodukter & återvinningssystem

AREA 1: Future

production and process systems

AREA 2:Optimum raw material design

AREA 3: Sustainable energy strategies

AREA 4: Residualproducts and recycling systems

Process Integration

Method development

Method adaption

TEMA 1:

Framtida produktionssystem

TEMA 2:Optimal råmaterialdesign

TEMA 3: Effektiva & uthålliga energisystem

TEMA 4: Analys av restprodukter & återvinningssystem

AREA 1: Future

production and process systems

AREA 2:Optimum raw material design

AREA 3: Sustainable energy strategies

AREA 4: Residualproducts and recycling systems

Process Integration

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Oxygen Plant

Heat and

Power Plant

Overall

Steelworks site

Sinter plant Lime kiln

Blast furnace

Hot stoves

Coke plant

Steel plant

Ancillary-

Onsite logistics

& other

Rolling

Integrated works

Energy &

material

“backpacks”

Global

Raw materials

Products

Byproducts

Pollutants

Wastes

Process Integration

Optimization Methodology

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System boundaryInputs Outputs

1. Define system boundary

Process 1 model

Process 2 model

Process 3 model…

Sub-models in ReMind or

discrete cases modelled in Excel

2. Develop/adapt sub-process models

ReMIND model

3. Apply optimization routine: reMIND, Mixed Integer Linear Programming

General Procedure

Layout of SSAB Luleå Works in Luleå

StränggjutningSkänkmetallurgiSvavelrening

Konverter

Koksverk

Masugn

Coke oven

Blast

furnace

Converter

Ladle

metallurgyDesulphurisation Continuous casting

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plant

Different ways to reduce CO2 emission

at SSAB Luleå Works

Potential reduction of CO2-emissions, kg/t crude steel

Process improvements

100% yield hot metal to crude steel

100% yield crude steel to slabs

Balanced liquid flow

Melting of scrap

Increased PCI rate

Reductant rate -20 kg/THM

Recycling +5 kg

Reduced flaring of BF-gas

More efficient heating of coke oven

Investments

Preheating hot stoves

Top pressure recovery

External cooperation

BF slag for cement production

Increased district heating

0 20 40 60 80 100 120 140 160

Utopisk hetvattenbalans

All slagg till slaggcement

Avgasturbin

Värmeväxlare cowpers

Undereldning

Minskad fackling

Recirkulering +5kg

Reduktionsmedel -20 kg/ton

Ökad kolinjektion

Skrotsmältning

Perfekt balans varma flödet

100% utbyte råstål till ämne

100% utbyte råjärn till råstål

Minskad emission vid hypotetiskt driftsfall, kg/ ton råstål

Processförändringar

Investeringar

Externt samarbete

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PI Example: Increase scrap in converter?

Ask the BF Manager:

- requires increase in HM Si & temp.

- increases BF coke rate & cost/thm

- reduces BF production

Ask the BOF Manager:

- increases productivity

- lowers raw material cost

Ask the environment manager:

- lowers CO2 emission/ton steel

Global implication with limited scrap supply:

The most sustainable solution, from an energy perspective, can be to use

the scrap in a converter at a steelplant with a lower efficiency blast

furnace!

Ask the shareholders:

- increases profit

Blast

Furnace

CO2

Stripping

Heater

CO2 to CCS

Recycle gas

70% CO

TG for firing

the heater

Top gas

Export Gas

Coke c.200 kgOres

O2 c. 230 Nm3

Coal c. 170 kgHot metal

slag

Heater

Off-gas

No export gas

For minimum coke rate

The Oxygen Blast Furnace

lower

upper

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CHP

Plant

240 MJ

2800 MJ

470 MJ

3510 MJ/thm

Conventional Blast Furnace

Coke Ovens

BOF

Example Process gas balance

700 MJ

(cowpers)

140 MJ

1200 MJ

880 MJ

Distance heat

Electricity

CHP

Plant240 MJ

2800 MJ

470 MJ

3510 MJ/thm

OBF

Coke Ovens

BOF

940 MJ

0 MJ

470 MJ

1410 MJ/thm

OBF installedConventional

Blast Furnace

Coke Ovens

BOF Extra energy 1000+ MJ/thm

What are electrical CO2 emissions?

Replacement energy for CHP?

Impact of OBF on Process gas balance

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CO2 emission reduction estimates - OBF

-10

10

30

50

70

90

Direct include

indirect

credit for

power

credit for

heat

%

OBF without CCS OBF with CCS

Increased electrical consumption

Decreased power production

or decreased

heat production

Transport

& Sequestration?

CO2 emission reduction example - OBF

Common Nordic Solution - Background

The annual production for the Nordic steelmaking

sites are between 600–2800 kton

Landfill volumes ~20-100 kton/a per site

Investment in alternative process is capital intense

and requires larger treatment volumes

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Idea

Invest in one installation for

treatment of all residues

Allows for an economy of scale

Logistics are suitable for the main

integrated works

Possible Technologies

RHF

Cupola Furnace

Detailed studies are underway

Centralised handling of residues

Conclusions

A process integration approach is important when evaluating

different ways of operating an integrated steel plant and for

evaluation of new technology

The result of an optimization can be quite different depending

on the selection of system boundary

E.g. The blast furnace compared to blast furnace + ancillary

operations + energy production in CHP plant

Communication of PI analyses to effectively convey the

results to all stakeholders must be further developed

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Thank you for your kind attention