An Industrial Ecology: Material Flows and Engineering Design

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An Industrial Ecology Material Flows and
Engineering Design

• David Allen
• Center for Energy and Environmental Resources and
• Department of Chemical Engineering
• The University of Texas at Austin

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Industrial Ecology What Is It?

• A metaphor, emphasizing the need to design
  industrial systems that mimic the mass
  conservation and material cycling properties of
  natural ecosystems
• A new set of business partnerships and systems
  that create synergies in supply chains
• A set of design tools to identify and optimize
  synergies and sets of environmental performance
  measures that can be used to assess performance
• The science of sustainability?

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An Industrial Ecology?

• Wastes, emissions
• Raw materials, Industrial Material
  Products
• energy Processing

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Industrial Ecology Factoids

• In most advanced economies, flows of materials
  are of order of 50 kg/person/day
• Most of these materials are used once, then
  discarded
• The value of these energy and material flows are
  enormous, so firms and individuals with the tools
  to identify valuable flows of resources will have
  significant competitive advantages

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What are the tools of Industrial Ecology?

• Life Cycle Assessments
• Material and energy flow analyses at a variety of
  spatial scales and focusing on individual
  processes, industrial sectors and entire
  economies
• Tools for measuring environmental performance
• Design tools for improving environmental
  performance

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Material flows at multiple scales

• Total material flows at national scales
• Flows of specific materials at national scales
• Flows of materials in industrial sectors
  (chemical process industries)
• Flows of materials in an integrated network of
  facilities (a network for end-of-life electronic
  products)

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Material flow accounts at national scales
U.S. National Research Council, Materials
Count, National Academy Press, 2003
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Examples of entries in a material flow account

• Flow of copper into the domestic economy (e.g.,
  from a domestic copper mine) or through imports
  (e.g., from Chile)
• Related hidden or indirect flows (e.g.,
  overburden removed during mining and the waste
  portion of copper ore) and emissions (e.g., to
  air, from mine roadways, mill operations,
  refining)
• Stock of products (e.g., autos), without
  distinguishing the products and
• Flows out of the economy as exports (e.g., in the
  form of finished products containing copper).

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Hidden flows
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Broad-based characterization of material flows
Fuels Minerals Biomass
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Broad-based characterization of material flows
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What is this stuff?
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Summary of bulk flows of materials at national
scales

• Hidden flows are significant
• Small stock accumulation
• A one-pass system where most material is
  discharged to air or water
• Some country to country differences

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Why should we care about national material flows?
Use wastes as raw materials?

• Wastes, emissions
• Raw materials, Industrial Material
  Products
• energy Processing

?
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Should we mine waste streams? Flows of metals in
hazardous wastes in the US

• 12 billion tons (wet basis) of industrial waste
  is generated annually in the United States
• Annual production of the top 50 commodity
  chemicals in the United States is 0.3 billion
  tons
• Annual output of U.S. refineries is 0.7 billion
  tons

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Industrial Hazardous Waste

• 0.25 - 0.75 billion tons/year
• 75 - 90 from chemical manufacturing
• Much of the rest from petroleum refining

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Hazardous waste flow mapping
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Should we mine waste streams?Consider the
Sherwood diagram value vs. dilution
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An economic opportunity?
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Material flows at multiple scales

• Total material flows at national scales
• Flows of specific materials at national scales
• Flows of materials in industrial sectors
  (chemical process industries)
• Flows of materials in an integrated network of
  facilities (a network for end-of-life electronic
  products)

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A more detailed look at the structure of material
flows

• Metal case studies

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Why metals?

• Easy to track
• Relatively simple chemistry and processing
• Significant in both material displaced and
  environmental consequences
• Advanced Recycling structures
• Interesting interactions

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Mercury

• A new opportunity for using material flow
  analyses?

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Why examine mercury (Hg)?
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Mercury use

• Industrial uses of mercury continue to decrease,
  so any material flow analysis is a snapshot that
  may change

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Mercury case study

• Emissions from coal fired power plants dominate
  the nations total emissions based on reported
  emission inventories

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Environmental forecastingMercury case study

• What emissions should be controlled?
• Regional case study for the New York
  Harbor/Hudson River drainage

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Environmental forecastingMercury case study

• Is the mercury loading in the harbor coming from
  air, wastewater, or seepage from landfills?

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Environmental forecastingMercury case study

• What are the major sources?

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Environmental forecastingMercury case study

• What are the policy implications of this material
  flow analysis?
• Are the findings for the New York Harbor likely
  to be replicated in other parts of the world?

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Metal case studies

• Lead Does lead in solder in electronic products
  pose a significant risk?
• Cadmium Should cadmium in batteries be phased
  out?
• Arsenic What do we do with accumulating stocks
  of CCA (pressure) treated lumber?
• Silver Where did the silver in San Francisco Bay
  come from?
• Mercury Will controlling mercury from power
  plant emissions significantly lower exposures?

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Material flows at multiple scales

• Total material flows at national scales
• Flows of specific materials at national scales
• Flows of materials in industrial sectors
  (chemical process industries)
• Flows of materials in an integrated network of
  facilities (a network for end-of-life electronic
  products)

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Many technology mixes are possible for a fixed
set of raw materials and products
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Input-output structure of the industry

• Define how processes are interconnected
• Note that multiple pathways exist for getting
  from inputs to end products
• Optimize structure at a systems level

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Formulate as a mathematical programming problem

• Each technology has energy and mass input
  requirements
• Each has a different set of environmental
  performance indices
• Consider the performance indices of cost and
  toxicity of chemicals used (as measured by TLV)

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Select a set of technologies that minimize cost,
or a set that minimizes toxicity of intermediates
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Identify the sources of residual toxicity these
are candidates for alternative reaction pathways
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Material flows at multiple scales

• Total material flows at national scales
• Flows of specific materials at national scales
• Flows of materials in industrial sectors
  (chemical process industries)
• Flows of materials in an integrated network of
  facilities (a network for end-of-life electronic
  products)

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End-of-Life Electronics
A cash cow? Or an economic burden?
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Expected Mass Flow

• 3 to 4 billions pounds per year
• Steady state
• By 2010
• 4 to 5 billion pounds per year
• Older units coming out of storage
• Estimate peak between 2005 and 2008

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Electronics Recycling 1980s

• Typical system being retired had the following
  characteristics
• 10 years old
• Large units (50 lbs or more), large pieces
• Steel, unpainted, mechanical attachments
• Gold or aluminum wire bonds, gold backed chips,
  high base and precious metal content on boards
• CRTs a small portion by weight and quantity
• Peripherals not common
• Market for new electronics
• Unsaturated in US, virtually non-existent in
  developing countries

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Electronics Recycling 1990s

• Typical system being retired had the following
  characteristics
• 5 years old
• 30-50 lb units, moderately sized pieces
• 50 steel, some painted, mixture of mechanical
  attachments and adhesives
• Wire-bonded (Al, some Au) and surface mount
  (Sn/Pb) chips, moderate base and precious metal
  content on boards
• CRTs approaching half by weight and quantity
• Peripherals somewhat common
• Market for new electronics
• Partially saturated in US, unsaturated in
  developing countries
• Moderate cost per function

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Electronics Recycling 2000s

• Typical system being retired had the following
  characteristics
• 2-3 years old
• 10-30 lb units, numerous small pieces
• 10 steel, many painted, significant use of
  permanent attachments and adhesives
• Surface mount chips, moderate base and precious
  metal content on boards
• CRTs approaching half by weight and quantity
• Peripherals somewhat common
• Market for new electronics
• Highly saturated in US, developing countries
  prefer new
• Low cost per function

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Based on 2005 mind set

• Focus solely on material recovery
• Optimize for minimal labor and storage and for
  maximum purity of material streams
• Assume existing product flows and material price
  structures
• Assume existing separation and sort technology

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The Concept
Thermoplastic
Glass
Base/Precious metals
Steel
Aluminum
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Preferred w/in EIP flow
EOL Electronics
Prescribed cross boundary flow
Boundaries
Optional cross boundary flow
EIP
Disposition Center
Product Resale
Material Separation and Recovery
Off-site purification and use
Materials fromoff-site
Landfill
Compost
On-site material purification
Power from methane
Materials fromoff-site
Molded ETP parts
Plastics Compounder
Injection Molder
Off-site plastics compounder
Off-site injection molder
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Material flows at multiple scales

• Total material flows at national scales
• Flows of specific materials at national scales
• Flows of materials in industrial sectors
  (chemical process industries)
• Flows of materials in an integrated network of
  facilities (a network for end-of-life electronic
  products)

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An Industrial Ecology?

• Wastes, emissions
• Raw materials, Industrial Material
  Products
• energy Processing

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