Supply Loops Material Recycling Definitions

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Supply Loops - Material Recycling Definitions
Primary material production
Product manufacturing
Use
Disposal
Material reprocessing
Secondary output
eol recycling efficiency rate Eol collection
rate Eol reprocessing yield
Available secondary resource
Collected secondary resource
Available secondary resource
Secondary output
Collected secondary resource
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Supply Loops - Material Recycling - Definitions
Primary material production
Product manufacturing
Use
Disposal
Material reprocessing
eol recycling efficiency rate Eol collection
rate Eol reprocessing yield
Total recycling input rate Total recycling
efficiency rate
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Supply Loops Material Recycling Infinite
Cycles
Primarymaterials production
End-of-life product disposal
Materials use
Collection recycling
collection rate for each cycle
recycling efficiency rate for each cycle
recycling yield for each cycle
Question How much recycled material do I get
from m primary material?
Total amount of material (assuming unlimited
recyclability) is Summing this series gives of
which
is secondary (recycled)
material. Overall recycling efficiency rate (
for infinite cycles)
Example r 0.66, P 1kg M 3kg P 1kg
primary S 2kg secondary
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Supply Loops Environmental Performance 100
yield
Production Eprod
End-of-life disposal Edisp
Use Euse
Overall recycling efficiency rate
Collection Ecoll
Reprocessing Erepro

• Life cycle impact (of a chosen environmental
  impact category)
• Without recycling
• With recycling
• Change in life cycle impact
• Recycling reduces life cycle impact if

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Supply Loops Environmental Performance
Limited yield
Production Eprod
Use Euse
End-of-life disposal Edisp
Collection Ecoll
Reprocessing Erepro

• Life cycle impact (of a chosen environmental
  impact category)
• Without recycling
• With recycling
• Change in life cycle impact
• Recycling reduces life cycle impact if

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Case study Recycling and reuse of structural
steel sections in construction
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Case study Recycling and reuse of structural
steel sections in construction
Product life cycle
Use of buildings and other structures
BF Section production 28.5GJ / tonne
Fabrication of sections 4.8GJ / tonne
Use of sections in construction 2.0GJ / tonne
EAF Section production 10.8GJ / tonne
Re-fabrication of sections 4.8GJ / tonne
Section recovery via deconstruction 0.4GJ / tonne
Section recovery via demolition 0.4GJ / tonne
Landfill of sections 1.3GJ / tonne
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Case study Recycling and reuse of structural
steel sections in construction
Environmental evaluation of supply loops for
steel sections
Factor 2
Factor 5
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Oberservation1 Section reuse requires less
energy than section recyclingThe more we reuse
instead of recycle, the better
Difference between reuse and recycling
reuserate
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Observation 2 Energy requirements of reuse may
increase with increasing reuse rateThere might
therefore be an optimal reuse rate
Difference between reuse and recycling
reuserate
The more we reuse, the more difficult
deconstruction and refabrication becomes.
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Case study Reusing Components in Durable Goods
Model
Product demand use
Product manufacturing Eman
1-yc
1-c
yc
c
Eol product collection insp. Ecoll
End-of-life product disposal Edisp
Product remanufacturing Ereman
yc
(1-y)c

• Environmental impact
• Without reuse Eman Edisp
• With reuse (1-yc)Emanyc Ereman c Ecoll
  (1-yc) Edisp
• Change in environmental impact
• ?E ycEman ycEdisp - ycEreman - cEcoll
  gross reduction - additional
  impact
• c collection rate, y reuse yield, product between
  c and y is reuse rate Ryc

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Supply loop constraint Limited component
durability
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Supply loop constraint Limited component
durability
Example Average number of lives n 3
Collection rate c 0.1 Total collected
111 Total reused 110
1
Reuse yield y
Collection rate c
1
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Supply loop constraint Limited component
durability
Example Average number of lives n 3
Collection rate c 0.5 Total collected
875 Total reused 750
1
Reuse yield r
Collection rate c
1
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Supply loop constraint Limited component
durability
Example Average number of lives n 3
Collection rate c 0.9 Total collected
2439 Total reused 1710
1
Reuse yield r
Collection rate c
1
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Limited component durability impacts technical
feasibility of reuse
Ryc
Ryc
c
n
Reuse rate yc is now a non-linear function of
the collection rate c and the average number of
lives n
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Total environmental impact is a non-linear
function of the collection rate c
Beyond a certain collection rate environmental
impact starts to increase again.
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Conclusions
In supply loops the additional environmental
impacts ofcollection and reprocessing need to be
traded off against the saved environmental
impacts of primary production and disposal. In
constrained supply loops more is not always
better. Supply loops may haveenvironmentally
optimal collection rates anywhere between 0 and
100.

• In product systems with reuse the environmental
  impacts of the processes need to be assessed and
  managed in an integrated way withthe three basic
  supply loop constraints
• the access to end-of-life products
• the feasibility of the reprocessing
• and the market demand for the secondary resources

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Case study Iron and Steel in the UK

• Scope and system boundaries
• Document and analyze the iron steel flows of
  the UK from 1970-2000
• Calculate the current recycling rate
• Boundaries of the material stocks are the
  geographical borders of the UK
• Account for trade

• Process groups
• Production (integrated steelworks, EAF mills,
  foundries)
• Fabrication and manufacturing (component and
  product manufacturing)
• Use

• Material categories
• Iron ore
• Iron and steel scrap - Home scrap (generated
  at iron and steel foundries and mills) -
  Prompt or new scrap (generated during fabrication
  and manufacturing) - End-of-life or old scrap
  (generated when iron and steel containing goods
  leave the use phase)
• Iron and steel industry products (e.g. castings,
  ingots, billets, rods, bars, sections,
  plates, strip, sheet, etc.)
• Iron and steel contained in new final goods (
  of iron and steel in goods)

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Case study Recycling Rate of Iron and Steel in
the UK
Material and process flow model of the UK iron
and steel cycle
Trade
Trade
Trade
Iron steel products
Iron steel in new goods
Iron ore
Production
Use
Fabrication manufacturing
C
Iron steel scrap
TSG
Loss
Ex
Im
UK border
Trade
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Case study Recycling Rate of Iron and Steel in
the UK
Ex
Im
C
TSG
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Case study Recycling Rate of Iron and Steel in
the UK
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Case study Recycling Rate of Iron and Steel in
the UK
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Case study Recycling Rate of Iron and Steel in
the UK
I S in new final goods entering use in the UK
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Case study Recycling Rate of Iron and Steel in
the UK
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Case study Recycling Rate of Iron and Steel in
the UK
Total scrap generation versus actual scrap
consumption
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Case study Recycling Rate of Iron and Steel in
the UK
Results and sensitivity analysis
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Reading for Thursday, 13 NovemberEhrenfeld
Gertler (1997) Industrial Ecology in Practice
The Evolution of Interdependence at Kalundborg,
J. of Ind. Ecol. 1(1), 67-79 (is posted on
course website)