layered sustainability assessment framework

Layered sustainability

assessment framework

Mr. Hannu Suopajärvi

University of Oulu

Laboratory of Process Metallurgy

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Contents of the presentation

• Introduction

• Definition of sustainability

• Layered sustainability assessment framework

• Methodology description

• Methodology illustration by case study

• Conclusions


University of Oulu

Laboratory of Process Metallurgy 2

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Introduction

• Sustainability issues are becoming more important in companies

• Steel industry has made substantial improvements during the last decades

• Evaluation of sustainability

• The scope of analysis has extended

• Several tools and methodologies have been developed to evaluate environmental performance

• LCA is the most used

• Sustainability is however more than environmental performance


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Sustainability

• The most cited definition for sustainable development

(Brundtland 1987):

• “...is development that meets the needs of the present

without compromising the ability of future generations to

meet their own needs”

• Three pillars of sustainability are environmental,

economic and social

• Several frameworks that assist organizations in path

towards sustainability have been proposed

• The Natural Step framework with Four System

Conditions that describe the principles of sustainability


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Layered sustainability

assessment framework

• Systematic procedure to evaluate dimensions of sustainability from small-scale to wider systems

• Division into three layers: • Unit process

• Plant site with surrounding society

• Global assessment

• The potential towards sustainability is separately evaluated in three distinct layer

• Objective of the study determines the use of tools within the layers

• Especially suitable for change-oriented studies

• Technology dimension has been taken to complement the sustainability assessment


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Layered sustainability assessment:

Unit process

• Evaluation of the process performance

• Sustainable technology affects the other dimensions of

sustainability

• Possible measures

• Investment costs

• Raw material costs

• Process efficiency and robustness

• Specific energy consumption (SEC)

• Best Available Technology (BAT) used


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Plant site and surrounding society

• Evaluation of the process and operation integration

efficiency in the plant site and with surrounding society


• Specific energy consumption (SEC)

• Plants level integration by e.g. industrial parks,

according to principles of Industrial Ecology or Industrial

Symbiosis (IS)

• By-product utilization efficiency


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Global scale

• Taking the whole product life cycle into account

• Evaluation of the system wide potential to pursue

sustainability


• Availability of raw materials

• Sustainable use of raw materials

• Share of virgin raw material replacement with by-

products from other industries

• Gross energy requirement (GER)

• Up and downstream environmental burden


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Examples to pursue sustainability

System level Environmental dimension

Economic dimension

Technology dimension

Social dimension

Global level Using the natural

resources that are well

managed

Reducing the amount

of emissions released

to air and land

Reducing the use of fossil fuels

Flexible platforms for

investments

throughout the value

chain

Assessment of the

upstream process

technologies

Selection of

trusted and

well-known suppliers

Plant level

(surrounding society)

Increasing the internal

recycling of by-

products (dust, scales,

gases)

Investigating local raw materials – availability

Carbon trading,

waste costs, effect of new raw materials

Increasing the

process integration

(Eco-industrial parks) Energy efficiency

Integration

with

surrounding society

Unit process Increasing the use of

renewables Raw material mix and

their costs (LCC) Investing in BAT

Capturing system

development

Risk

management


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Methodology for assessing

large-scale systems

• Foreground and background system

• Foreground system • Integrated steel works

• Process modeling in adequate level

• Factory Simulation Tool

• LCI-kind data for evaluation

• Base case with normal operation

• Background system • Wider effects of changes made in

foreground system level


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Lime burning kilns

BF

BOF

Desulphurization

Secondary steelmaking

Casting

Rolling

Power plant

Foreground system

Coke plant

Material flows Flow Unit Quantity Material inputs Pellets kg/FU 1278 Briquettes kg/FU 100

Coal kg/FU 438

BF oil (injection) kg/FU 90 Scrap kg/FU 202

Limestone kg/FU 164.4

Burnt lime kg/FU 60.2

Dolomite kg/FU 13.3

Energy inputs Electricity kWh/FU 364 Intermediates Coke kg/FU 361.5 Pig iron kg/FU 966.4

Slabs kg/FU 1030.4

COG Nm3/FU 173.6 BFG Nm3/FU 1383.3 BOFG Nm3/FU 93.2 Material outputs Slags kg/FU 330 Tar kg/FU 11.8

Product Hot rolled plate kg/FU 1000 Emissions to air CO2 kg/FU 1727.5 SO2 kg/FU 0.46

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Application of layered assessment

• Biomass use in iron and steelmaking as charcoal injection to blast furnace

• Indicative study to present the layered assessment methodology

• Emphasis on unit process and plant site system assessment

• The background system data gathering was kept in minimum in this study

• Indicators selected for sustainability assessment are case-specific and depend on the problem in question


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System level

Environmental dimension

Economic dimension

Technology dimension

Global level

Share of fossil CO2 emissions

Charcoal

cost in global scale

Sustainable

charcoal production

Plant

level (society)

Availability of

renewable

biomass

Cost of

charcoal

compared

to other reductants

Charcoal

production

capacity

By-product

utilization rate

Unit process

Impact on

specific CO2

emissions

Cost of charcoal

Needed

charcoal

amount to

replace fossil

reductants

Effect to the

product quality

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Unit process level assessment

S1 S2 S3 S4 S5 S6

Coke 361.5 361.5 311.5 361.5 269.5 -

Oil 90 50 90 - - -

Char

coal - 48 50 108 200 469.5

Total 451.5 459.5 469.6 451.5 469.5 469.5

• Can be considered as technology assessment

• Blast furnace model • Fulfillment of mass and heat balance

• The replacement ratio of charcoal was 1.2 against oil injection

• Pyrolysis unit • Yield of charcoal 35 %

• Mass yield of utilizable by-products 40 %

• Positive impacts on produced pig iron

• Low sulfur content

• Low ash content

• CO2 reduction potential can be substantial


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0

200

400

600

800

1000

1200

1400

1600

scenario 1 scenario 2 scenario 3 scenario 4 scenario 5 scenario 6

Red

ucti

on

in fo

ssil C

O2 e

mis

sio

ns

[kg

CO

2/F

U]

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Unit process level assessment

S2 S3 S4 S5 S6

Charcoal [kg] 48 50 108 200 469.5

Dry wood [kg] 137.1 142.9 308.6 571.4 1341.4

Wet wood [kg] 219.4 228.6 493.7 914.2 2146.1

Charcoal [kt] 124.8 130.0 280.8 520.0 1220.7

Dry wood [kt] 356.6 371.4 802.2 1485.6 3487.7

Wet wood [kt] 570.5 594.2 1283.5 2376.9 5579.8

Wet wood [Mm3] 0.76 0.79 1.71 3.17 7.44

• The amount of needed biomass (wood) in yearly basis (2.6 Mt steel production) is extensive

• Raw material characteristics • Fresh wood 50 % moisture, 4.57

kg wet wood per kg charcoal

• Dry wood 20 % moisture, 2.86 kg dry wood per kg charcoal

• The cost of charcoal is challenge

• High raw material costs

• High transport and machinery costs due to sparse raw material source compared to tropical plantations


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0.00

100.00

200.00

300.00

400.00

500.00

600.00

700.00

Charcoal production

Energy wood

Timber Cutting and

bundling

Forest haulage

Transport cost (truck

100 km 25m3)

Chipping Total cost [energy

wood]

Total cost [timber]

cost

s (e

ur/

t ch

arco

al)

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• Charcoal production was assumed to be in plant site

• Utilization of by-product in electricity and heat production

• The energy content of by-products is 16 MJ/kg

• Production of one ton charcoal yields 18.3 GJ of utilizable energy

• Indicative calculation results for price increase

• With the cheapest raw material (energy wood) the economic sustainability may be achieved

• The importance of by-product utilization

• No CO2 taxes taken into account


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Ccoal 150 €/t

Ccoke, int 190 €/t

Coil 150 €/t

Ccharcoal, energy wood 343 €/t

Ccharcoal, timber 630 €/t

Celectricity 50 €/MWh

Cheat 10 €/MWh

0

5

10

15

20

25

30

35

40

45

50

scenario 1 scenario 2 scenario 3 scenario 4 scenario 5R

ela

tive in

cre

ase in

co

sts

to

base c

ase [%

]

The cost increase to base case no credits

The cost increase to base case with electricity credit

The cost increase to base case with electricity and heat credit

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• Availability of affordable raw material is challenge

• Changes in global energy price affect the competitiveness of biomass as energy source

• The competing use of wood affects the availability and price

• The capacity of the Finnish pulp and paper and wood product industries declines – Estimated use of domestic timber in 2020 is 12.4 Mm3 lower than in 2007

• There has been a surplus in Finnish forest resources

• Growth 100 Mm3 , yearly use 60-70 Mm3, sustainable use estimated 72 Mm3

• The analysis of available wood resources within suitable transportation range show that there might be enough raw material for charcoal production


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[Mm3/y] Reg.1 Reg.2 Reg.3 Reg.4 Reg.5 Total

Energy wood 1.4 1.1 1.0 1.45 1.3 6.25

Timber 6.4 6.0 4.4 5.7 6.4 28.9

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Global assessment

• In many studies LCA is done to evaluate the impacts of product in life cycle basis

• This study indicatively evaluated the CO2 emission reduction potential and price of the charcoal in global scale

• From the assessed scenarios the one closest to economic sustainability would decrease the CO2 emissions by 14.3%

• CO2 reduction potential could be even negative because of the by-product use, however not realistic in any dimensions of sustainability

• One possibility would be the production of charcoal in tropical countries where the price is lower

• Prices reported are below 300 €/ton charcoal

• Difficulties with this option: • Sustainable production technology and by-product utilization

• Shipping and other costs

• Uncontrolled environmental and social impacts


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Conclusions

• Layered sustainability assessment framework • Systematic evaluation of important factors affecting the sustainable

decision-making

• Framework helps to identify the needed case-specific evaluation tools and measures

• Turns the vague concept of sustainability to more tangible measures and actions

• Application of framework to assess sustainability of biomass use in iron and steelmaking

• Unit process assessment and majority of the plant level indicators showed that there is potential to pursue sustainability with charcoal use

• Challenges relate to availability of raw materials and the cost structure of charcoal, which is affected by the high price of raw material

• Prerequisite for sustainability of biomass use is the utilization of by-products from charcoal production stage

• More detailed assessment of supply chain structures and production technologies for charcoal production will be a subject for further studies


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layered sustainability assessment framework

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