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Module 2: Chemical and Physical Characteristics of Ethanol and Hydrocarbon Fuels. 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. Introduction.
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Module 2: Chemical and Physical Characteristics of Ethanol and Hydrocarbon Fuels
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.
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
Activity 2.1 — Definitions • Purpose: • To allow participants to identify the definitions related to ethanol.
Characteristics of Gasoline (A Hydrocarbon) • Similar characteristics whether flammable / combustible liquids • Produced from crude oil by fractional distillation • Non-water miscible / insoluble • Flash point -45°F (depending on octane rating)
Characteristics of Gasoline (A Hydrocarbon) • Vapor density between 3 & 4: • Gasoline vapors seek low levels / remain close to ground level • Specific gravity of 0.72–0.76: • Will float on top of water • Auto-ignition temperature between 536°F & 853°F • Boiling point between 100°F & 400°F
Characteristics of Gasoline (A Hydrocarbon) • 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
Characteristics of Ethanol (A Polar Solvent) • Ethanol used with motor fuels denatured with up to 5% gasoline / similar hydrocarbon for transport • Denaturant has minimal effects on characteristics
Characteristics of Ethanol (A Polar Solvent) • Renewable fuel source produced by fermentation & distillation process • Most common source in U.S. in 2008 is corn • Polar solvent • Water-soluble • Flash point 55°F
Characteristics of Ethanol (A Polar Solvent) • 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 793°F
Miscibility Figure 2 Figure 1 Figure 3
Characteristics of Ethanol (A Polar Solvent) • Boiling point 173°F • 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
Characteristics of Ethanol (A Polar Solvent) • 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
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.
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
Characteristics of Ethanol-Blended Fuels • Gasoline floating on layer of ethanol / water solution • Resulting ethanol / water solution still flammable
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
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
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