Topics for Today

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Sam dedication lecture!
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(No Transcript)
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Topics for Today

• Whats all the other stuff in my gasoline?
• Quiz 8

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Topics for Today

• Gasoline additives (MTBE, ethanol, and oxygenates)

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Readings for Today

• 4.10 Newer fuels and other sources

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Topics for Monday (April 10!)

• The other part of crude oil

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Topics for Monday (April 10!)

• Plastics
• Polyethylene

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Readings for Monday

• 9.1 Polymers The long, long chain
• 9.2 The Big Six
• 9.3 Addition polymerization
• 9.4 Polyethylene

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Topics for Today

• Whats all the other stuff in my gasoline?
• Quiz 8

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Review
What is the problem with using winter blends in
the summer?
Is the gasoline in the winter more or less
volatile than in the summer?
MORE!
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What is wrong with VOCs?
Becomes more volatile ? VOCs!!
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Should you use the summer blend in the winter?
Why not?
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Does this have anything to do with the octane
number?
NO!!
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What is the octane number?
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• Octane number A measure of how effective a fuel
  can resist engine knock.

In other words, how smooth is the combustion of
the fuel?
What is engine knock?
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High octane number smooth burning fuel. More
of a controlled burn.
Low octane number Uncontrolled explosion
How do we determine octane number?
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octane rating 100
Define!

• Iso-octane
• CH3 CH3
• CH3 C CH2 CH CH3
• CH3

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octane rating 0
Define!
n-heptane
H
H
H
H
H
H
H
C
C
C
C
C
C
C
H
H
H
H
H
H
H
H
H
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In the old days
Mix various amounts of n-heptane and isooctane to
see when a test-engine will knock.
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• n-heptane 0
• Isooctane 100

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Another example
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Octane -20!

• n-octane
• CH3CH2CH2CH2CH2CH2CH2CH3

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octane rating 100

• Iso-octane
• CH3 CH3
• CH3 C CH2 CH CH3
• CH3

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Branched molecules tend to have higher octane
numbers!
Why do we care?
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The gasoline from crude oil has an octane number
of about 60-70.
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BUT
Recommended for most cars
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Why do we use fuel additives?
1) To increase the octane number
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Octane rating 123!

• Benzene

Very toxic. Not used too much anymore
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Octane rating 114!

• Toluene

CH3
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Octane rating 108!

• Ethanol
• H H
• H C C OH
• H H

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Alcohol R O H
R some hydrocarbon group (methyl, ethyl, etc)
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Very smooth burn!
Ethanol Ring of Fire!
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Tetraethyl lead
Octane rating 270!
CH2CH3 CH2CH3
Pb CH2CH3
CH2CH3
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Also called ethyl in the old days
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TEL
Why not?
TEL is not used anymore
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Criteria Pollutants
Lead is an extremely potent neurotoxin

• Defined by the EPA
• CO
• SO2
• NOx
• PM2.5 and PM10
• O3 (ozone)
• lead

TEL was banned in the US in 1976
Lead is not very interesting anymore
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If you put 89 octane into your 87 octane car
NOPE!
More power?
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Why do we use fuel additives?
1) To increase the octane number
2) To make a cleaner fuel
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Oxygenates!
Take a hydrocarbon
And just add oxygen!
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Why add oxygen to the fuel?
Review
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If we add oxygen to the fuel, then we can reduce
CO and PM emissions!
Complete Combustion
C O2 ? CO2 C ½ O2 ? CO C O2 ? C O2
Not enough oxygen
Severely depleted oxygen
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Oxygenates
An alcohol

• Ethanol
• H H
• H C C OH
• H H

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Spark Plug
Ethanol cannon!!
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Why must ethanol be added at the pump?
Polar or nonpolar?

• H H
• H C C OH
• H H

Is gasoline polar or nonpolar?
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(No Transcript)
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Whats good about using ethanol?
1) Reduced CO emissions
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2) Less direct impact if spilled
Whats good about using ethanol?
1) Reduced CO emissions
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Problems with ethanol?
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(No Transcript)
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September 2005 Report
What if WI mandated the use of 10 ethanol across
the state??
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Air Pollution Implications
- means decreased emission means increased
emission
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Problems with ethanol?
1) Air pollution compromise