Automobile Emissions Controls

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Chapter 9
Automobile Emissions Controls Stationary
Emissions Control Cost of Emissions
Controls Thermal Pollution from Energy
Generation Ecological Effects of Thermal
Pollution Cooling Towers Using Waste Heat
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Energy in the News
Thursday Energy Roundtable at SIPA Cancelled
Not yet rescheduled
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Automobile Emissions Controls
Emissions can be controlled in several
ways Change the fuel used by the car Change the
way that the engine burns the fuel Decrease the
use of cars by subsidizing mass transit
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Changing the Fuel
What are other names for methanol, ethanol and
compressed gas? How are they made? Other
drawbacks of these fuels?
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The Newest Fuel Nitrogen
Newest alternative fuel (reported this
Monday) Works by using decompression of Liquid
nitrogen to Push pistons and run The car
engine. No pollutants at all, BUT Technology not
mature.
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Changing the Burning Process
More efficient cars emit less CO2 per mile
traveled. (In the 1970s, estimated that could
run All cars on ethanol and methanol derived from
Fermented biomass if all cars averaged 60
miles Per gallon.) Number is out of date, but
at some gas mileage It is possible to run all
cars on renewable sources Of hydrocarbons. Amory
Lovins using the best technology Could
potentially build cars That get 150 miles per
gallon.
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Positive Crankcase Ventilation
At the edges of the combustion Chamber of the
engine (above the piston tops), there is a thin
layer of gasoline that does Not burn up. This
gasoline Constitutes an air pollutant (what is
its classification?) To keep gasoline from
returning to The air, this gasoline is
recirculated Back into the combustion chamber.
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Exhaust Gas Recirculation
Exhaust gases are Removed from the Crankcase and
then Recirculated back into The carburetor.
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Other Pollution Controls
Minimize CO and hydrocarbons by improving
burning Of the fuel. To improve burning use
leaner fuels and increase Temperatures in the
combustion chamber. Leaner fuels means mixture
of air plus fuel has more Air and less fuel. But
leaner fuels increase Nox formation because
Burning is at higher temperatures and more
oxygen is Available to form Nox. Catalytic
converters help to get around these
problems. They require unleaded gasoline.
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Automobile Emissions Standards
Standards met by using catalytic converters,
engine Redesign and additives (MBTE, other
oxidants).
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Mass Transit
Shin Kan Sen (Bullet Train), TGV (Train Grande
Vitesse) Both are MAGLEV (magnetic levitation)
trains Travel at up to 300 km/hr (180 mph) Shin
Kan Sen Trains leave every 3 hours
Tokyo-Kyoto TGV-not so often Buses like
subways(pay fare before getting on in enclosed
area) Most efficient form of public
transport Exist in Brazil Biggest problem Load
factor If not used enough, mass transit is LESS
energy efficient than cars 90 of public funds in
US used to build highways
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True Energy Use by Transportation
In theory, a train Is 15 times more Energy
efficient than A car. Considering
load Factors, what is The more typical Ratio of
efficiency? What is the most Energy
efficient Transportation?
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Reducing Pollution from Stationary Sources
How pollution is reduced 1) Change the fuel 2)
Change how the fuels burns 3) Remove pollutants
after burning Other methods dont really reduce
overall pollution, they Shift it in time or in
space, what are these methods?
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Shifting the Pollution in Space
Sudbury Ontario giant astrobleme-Worlds biggest
Ni mine One of two oldest meteorite impact
structures 1.8 Ga (1800 Ma) (Canadian Nickels)
Ni is a heavy metal large quantities Are
poisonous to people and plants. What did
building a Taller smoke stack at Sudbury do to
the landscape? (Dumping the slag)
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Shifting the Pollution in Time
Why does shifting the time at which emissions are
made Affect the resulting air quality? (Ozone for
example). Other strategies not so nice. (At U.S.
Mexican border). El Paso area?
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Removing the Pollution
Mary Walton invented an early pollution control
device For factories.
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Power Plant Pollution Control
What is being Removed by The electrostatic Precipi
tator? By the wet Scrubber?
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Fluidized Bed Combustion
Key Reaction CaO (lime) 1/2O2 SO2 CaSO4
(calcium sulfate) Limestone CaCO3 What else
besides calcium sulfate Is emitted by Fluidized
Bed Combustion (FBC)? FBC reduces NOx by
lowering Temperature of burning
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Cleaning the Coal by Crushingand Settling
FeS2 or pyrite (fools gold) Very dense. Can
separate from coal using Settling techniques.
Why? This cleans the coal of part Of its sulfur.
Remaining sulfur chemically Bonded with the
coal.
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Cost of Pollution Controls
Cost of pollution controls Left normalized to
100 Cost for all pollution Controls Right as a
percentage of Total power plant cost (only one
line is relevant) Actual cost typically About
1/3 of plant cost
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Physics of Waste Heat
Q m c deltaT Q is heat added, m is mass, c
is specific heat Delta T is the temperature
change What is waste heat? Why do you get always
get waste heat when You generate power using a
heat engine?
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Waste Heat and Water Use
Which users are Increasing their water
consumption the most? 1855 to 1980? 1980 to
2000? (Graph is for the United States) Why?
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Waste Heat from Power Plants
Which portion of the waste heat goes to heat up
water In a water-cooled plant? Which plant type
generates The most waste heat per unit of power
output?
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Dissolved Oxygen in Water vs T
How does the amount Of dissolved oxygen in The
water change as a Function of temperature? Why? P
VnRT
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Oxygen Consumption of Fish vs T
Why do fish need more oxygen As the temperature
of the water Increases? Given the solubility of
oxygen In water as a function of temperature (in
the previous slide), what happens to the fish if
the water gets too hot? Why would it be
difficult to publish This graph?
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Fish Response to Temperature
Solid dot Upper lethal Limit for a Given
species Open dot Best T for spawning Solid
blocks Preferred Temperature Range
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Temperature and Growth of Food Animals
What is the optimum Temperature for Hens,
catfish, shrimp?
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Thermal Pollution from Power Plants
Eutrophication Natural aging of Lakes Promoted
by waste Heat from power Plants. Why?
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Natural Draft Cooling Tower
Why does this cooling Tower lack a fan?
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Mechanical Draft Cooling Tower
Why does this tower Need a fan? (Active vs
Passive Cooling Tower)
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Air to Liquid Heat Exchanger
What is the Heat being Extracted from? Why?
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Recuperator Also extracts heat
Why is it useful to heat incoming Air and cool
outgoing air (this is a heat engine)?
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Uses of Waste Heat
Cogeneration Aquaculture Greenhouse
heating Desalination of seawater Increase crop
growth in cold season Preheat air Other??