Module 2: Chemical and Physical Characteristics of Ethanol and Hydrocarbon Fuels

1

• Module 2 Chemical and Physical Characteristics
  of Ethanol and Hydrocarbon Fuels

2
Objective

• Upon the successful completion of this module,
  participants will be able to describe the
  chemical and physical differences between pure
  gasoline and gasoline / ethanol blends.

3
Introduction

• Characteristics of polar solvents hydrocarbons,
  their differences, how they interact
• Conditions under which ethanol-blended fuels
  will retain certain characteristics of types of
  fuel
• Help emergency responders mitigate various
  incidents according to conditions found

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Activity 2.1 Definitions

• Purpose
• To allow participants to identify the definitions
  related to ethanol.

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Characteristics of Gasoline (Hydrocarbons)

• Similar characteristics whether flammable /
  combustible liquids
• Produced from crude oil by fractional
  distillation
• Non-water miscible / insoluble
• Ignition point (flash point) -45F (depending on
  octane rating)

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Characteristics of Gasoline (Hydrocarbons)

• Vapor density between 3 4
• Gasoline vapors seek low levels / remain close to
  ground level
• Specific gravity of 0.720.76
• Will float on top of water
• Auto-ignition temperature between 536F 853F
• Boiling point between 100F 400F

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Characteristics of Gasoline (Hydrocarbons)

• Not considered poisonous
• Harmful effects after long-term high-level
  exposure
• Can lead to respiratory failure
• Smoke from burning gasoline is black has toxic
  components
• Greatest hazard is flammability
• Fairly narrow range of flammability

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Characteristics of Ethanol (Polar Solvents)

• Pure ethanol in responses at ethanol production
  facility
• Ethanol used with motor fuels denatured with up
  to 5 gasoline / similar hydrocarbon for
  transport
• Denaturant has minimal effects on characteristics

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Characteristics of Ethanol (Polar Solvents)

• Renewable fuel source produced by fermentation
  distillation process
• Most common source in U.S. in 2008 is corn
• Polar solvent
• Water-soluble
• Ignition point (flash point) -5F

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Characteristics of Ethanol (Polar Solvents)

• Vapor density of 1.59
• Heavier than air
• Vapors do not rise
• Specific gravity 0.79
• Lighter than water
• Thoroughly mix with water
• Auto-ignition temperature 793F

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Characteristics of Ethanol (Polar Solvents)

• Boiling point 173F
• Less toxic than gasoline / methanol
• Carcinogenic compounds not present in pure
  ethanol
• Greatest hazard as motor fuel component is
  flammability
• Wider flammable range than gasoline

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Characteristics of Ethanol (Polar Solvents)

• In pure form no visible smoke hard-to-see blue
  flame
• In denatured form little to no smoke slight
  orange flame may be visible
• Ethanol some ethanol blends can conduct
  electricity
• Large amounts of water required to dilute ethanol
  to no longer support combustion

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Activity 2.2 Comparison of Gasoline and Ethanol

• Purpose
• To allow participants to discuss the differences
  similarities in the chemical physical
  properties of ethanol gasoline.

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Characteristics of Ethanol-Blended Fuels

• Ethanol increases heat output of unleaded
  gasoline
• Lower emissions from unburned hydrocarbons
• Minimal amounts of water will draw ethanol out of
  blend away from gasoline
• Ethanol gasoline more suspension than solution

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Characteristics of Ethanol-Blended Fuels

• Gasoline floating on layer of ethanol / water
  solution
• Resulting ethanol / water solution still flammable

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Characteristics of Ethanol-Blended Fuels

• Blending fuels alters physical chemical
  characteristics of original fuels
• Visual difference of smoke flame
  characteristics
• Higher content of ethanol, less visible black
  smoke content orange flame production

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Characteristics of Ethanol-Blended Fuels

• Blending fuels alters physical chemical
  characteristics of original fuels
• When foam / water flowed on burning product,
  gasoline tends to burn off first
• May have no visible flame or smoke

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Summary

• Polar solvent water-soluble flammable
• When blended with gasoline, produces slightly
  cleaner burn than gasoline alone
• Blend of gasoline ethanol can easily go
  unnoticed by emergency responders
• Ethanol will be last fuel to burn
• Ethanol will burn without visible smoke / flame