Topic 1. Introduction to Environmental Issues Green Chemical Engineering Workshops ASEE Chemical Engineering Summer School, 2002 University of Colorado, Boulder, CO

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Topic 1. Introduction to Environmental
IssuesGreen Chemical Engineering WorkshopsASEE
Chemical Engineering Summer School,
2002University of Colorado, Boulder, CO

• David R. Shonnard
• Associate Professor
• Department of Chemical Engineering
• Michigan Technological University

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Presentation Outline

• Pedagogical Approach - how to teach environmental
  issues to chemical engineering students
• Introduce environmental issues and establish
  linkages to chemical manufacturing activities
• Present environmental data trends over time
• Model environmental processes and compare to data
  trends
• Relate chemical properties to environmental
  impacts
• Discuss implications for environmental issues /
  problems
• Discuss potential solutions to minimize impacts
• Assign outside reading to students in key areas

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Educational goals and topics

• Students will
• be introduced to major environmental issues
  related to chemical processing
• understand the contribution of the chemical
  industry to these environmental issues
• Faculty will
• learn recommended approaches for presenting
  environmental literacy material in lecture

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Potential uses of the module in chemical
engineering courses

• Design course Introduce environmental literacy
  and regulations before assigning projects
• Freshman Engineering Introduction to issues
  regarding environment / society / industry

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Scope of environmental impacts
Materials
Materials
Materials
Materials
Life- Cycle Stages
Energy
Energy
Energy
Energy
Raw Materials Extraction
Chemical Processing
Product Manufacturing
Use, Reuse, Disposal
Pollution Control
Pollution Control
Wastes
Wastes
Wastes
Wastes
Midpoints
Human health and ecosystem damage
global warming
ozone depletion
smog formation
acidifi- cation
ecological harm
Endpoint
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U.S. energy flows, 1997
Annual Energy Review 1997, U.S. DOE, Energy
Information Administration, Washington, DC,
DOE/EIA-0384(97)
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U.S. industry manufacturing energy use
SIC Code 1015 BTUs/yr 29 Petroleum/Coal
Products 6.34 28 Chemicals / Allied
Products 5.33 26 Paper / Allied Products
2.67 33 Primary Metals Industries
2.46 20 Food / Kindred Products 1.19 32
Stone,Clay and Glass 0.94 24 Lumber / Wood
Products 0.49 Numbers represent roughly
the of US annual energy consumption
Annual Energy Review 1997, U.S. DOE, Energy
Information Administration, Washington, DC,
DOE/EIA-0384(97)
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Global warming and related impacts
Energy
Materials
Cause and Effect Chain
Products
Chemical Processing
greenhouse gas emissions CO2, CH4, N2O
Contribution to global Warming Phipps, NPPC,
http//www.snre.umich.edu/nppc/
Climate Change 1995, Intergovernmental Panel on
Climate Change, WMO and UNEP, Cambridge
University Press, 1996.
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Homework problem - emphasizing chemical
engineering concepts
Radiation Balance at the Earth - No Greenhouse
Effect
S 1,300 W/m2
RE
Rate of Heat Absorbed Rate of Heat Emitted
A average Albedo .30, e emissivity of the
surface 0.97 S Stefan-Boltzman Constant
5.67x10-8 Watts/( m2K4)
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Homework Problem - Emphasizing Chemical
Engineering Concepts
Radiation Balance at the Earth - With Greenhouse
Effect
.2 x
y
Atmosphere - absorptivity for solar 0.10
absorptivity for IR 0.80
.9 E
y
x
.9 E
y
x
Surface - IR absorptivity emissivity 1.0
Irradiance In Irradiance Out
x 1.58E s T4 or TS 277 K
Surface 0.9E y x Atmosphere 0.2x
y E
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Possible adverse effects of global warming

• Increased average temperatures and temperature
  extremes
• Melting of glaciers / polar ice and sea level
  rise
• Increased incidence of diseases such as malaria
  due to warmer temperatures
• Changing climate and altered weather patterns
• Disruption of land use due to droughts
• Migration of human populations
• Decreased life expectancy in some regions of the
  world

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Discuss potential solutions to global warming

• Increase energy efficiency of chemical production
  and electricity generation (cogeneration)
• Reduce fossil fuels usage (increase gas mileage
  for vehicles, more insulation for homes, etc.)
• Utilize renewable energy resources to a greater
  extent such as biomass, solar, hydroelectric,
  wind, ..
• Capture and sequester CO2 from combustion gas
  streams
• Create chemicals with lower global warming
  potential

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Stratospheric ozone depletion
Energy
Materials
Cause and Effect Chain
Products
Chemical Processing
ozone depleting substances CFCs, HCFCs
human mortality or life adjustments ecosystem
damage
(x1000 )
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Stratospheric ozone depletion (cont.)Figure
1.4-4
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Stratospheric ozone depletion (cont.)Figure
1.4-4
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CFC mole balance Atmosphere response to CFC
phase-out
1. Troposphere (0 - 10 km) is well-mixed 2.
Annual CFC production is emitted to atmosphere
(assumed)
yCFC mole fraction of CFC in the
troposphere ECFC (t) emission rate of CFC
(g/yr) ECFC eat (AFEAS web site) MCFC
molecular weight of CFC (g/mole) mATM
atmosphere content (1.5x1020 moles)
(Wallace/Hobbs, 1977, pg6) t CFC
residence time in the troposphere (yr) yCFC,o
mole fraction of CFC in 1988 (Figure 1.4.3)
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CFC mole balance model prediction
ppt yCFC x 1012
CFC-11. ECFCo 3.14x1011 g/yr, a 0.1796 yr-1,
MCFC 137.4 g/mole CFC-12. ECFCo 3.93x1011
g/yr, a 0.1250 yr-1, MCFC 120.9 g/mole
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CFC mole balance model Conclusions

• Conclusions
• Mole balance model captures the main trends in
  the data from Figure 1.4.4
• Assumption of well-mixed atmosphere is good
• Model predicts peak concentrations well
• Shorter residence time for CFC-11 (60 yr) caused
  its peak to occur earlier than CFC-12 (residence
  time 120 yr)

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Effects of chemical properties on ozone
depletion (Chapter 5)

• Summary of Environmental Properties/Behavior
• CFCs, HCFCs, Halons partition to atmosphere
  nearly 100
• Water solubility (v. low), Sorption to natural
  organic matter (v. low), vapor pressure and
  Henrys constant (v. high)
• Persistence in the atmosphere is v. high (v.
  small hydroxyl radical (OH) rate constant)
• Reactivity increases with addition of Hydrogen to
  molecule, e.g. HCFCs

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Smog formation and related impacts
Cause and Effect Chain
Energy
Materials
Products
Chemical Processing
human/ecological damage from O3 and other oxidants
NOx and volatile organic substances
1 - Chemical Allied Processing 2 - Petroleum
Related Industries
NOx
VOCs
NOx
1997
Miscellaneous
3 - Metals Processing, 4 - Other Industrial
Processes 5 - Solvent Utilization, 6 - Storage
Transportation 7 - Waste Disposal Recycling
Transportation
Industrial Processes
VOCs
1997
Fuel Combustion
National Air Quality and Emissions Trends Report,
1997, U.S. EPA Office of Air Quality Planning and
Standards, http//www.epa.gov/oar/aqtrnd97/chapter
2.pdf
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Acid rain / Acid deposition
Cause and Effect Chain
Energy
Materials
Products
Chemical Processing
human/ecological damage from H and heavy metals
SO2 and NOx emission to air
SO2
1997
Miscellaneous
1 - Chemical Allied Processing 2 - Petroleum
Related Industries 3 - Metals Processing 4 -
Other Industrial Processes 5 - Solvent
Utilization 6 - Storage Transportation 7 -
Waste Disposal Recycling
Transportation
Industrial Processes
Fuel Combustion
National Air Quality and Emissions Trends Report,
1997, U.S. EPA Office of Air Quality Planning and
Standards, http//www.epa.gov/oar/aqtrnd97/chapter
2.pdf
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Human health toxicity
Energy
Materials
Products
Chemical Processing
Transport, fate, exposure pathways routes
Human health damage carcino- genic non...
Toxic releases to air, water, and soil
EPCRA Toxic Waste
RCRA Hazardous Waste
Allen and Rosselot, 1997
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Hazardous Waste Management Options
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Ecology Concepts
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Ecological Impacts
La Grega et al. Hazardous Waste
Management McGraw Hill
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Short written report from external reading(1-2
page memorandum from students)

• Potential Environmental Topics Information
  Sources
• Global Warming Scientific/Eng. Journals
• Ozone Depletion in Stratosphere Environmental
  Sci. Technology
• Acidification Environmental Progress
• Smog Formation Chemical and Engineering News
• Toxic Chemicals in Commerce
• Industrial Hazardous Waste Internet Resources
• Genetically-Altered Foods American Chemistry
  Council
• Superfund Sites Clean-up US Environmental
  Protection Agency
• Pollution Prevention Technologies State
  Environmental Quality Office
• Endocrine Disruptors

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Presentation Summary

• Pedagogical Approach - how to teach environmental
  issues to chemical engineering students
• Introduce environmental issues and establish
  linkages to chemical manufacturing activities
• Present environmental data trends over time
• Model environmental processes and compare to data
  trends
• Relate chemical properties to environmental
  impacts
• Discuss implications for environmental issues /
  problems
• Discuss potential solutions to minimize impacts
• Assign outside reading to students in key areas