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

2 Objective Upon the completion of this module, participants will be able to describe the chemical & physical differences between gasoline & ethanol-blended fuels.

3 Introduction Characteristics of polar solvents & hydrocarbons, their differences, & how they interact Conditions under which ethanol-blended fuels will retain popular solvent characteristics as compared to all hydrocarbon characteristics

4 Characteristics of Gasoline Insoluble in water Produced from crude oil by fractional distillation Not considered poisonous: –Harmful effects after long-term & high-level exposure Smoke from burning gasoline is black & has toxic components Greatest hazard is flammability: –Fairly narrow range of flammability 1.4% - 7.2% by volume in air

5 Gasoline Production David Parsons/NREL

6 Characteristics of Ethanol Renewable fuel source produced by fermentation & distillation processes Most common feedstock in U.S. is corn Ethanol used with motor fuels must be denatured with 2% - 5% gasoline or similar hydrocarbon before transport to a bulk storage facilities Denaturant has minimal effects on characteristic

7 Feed Stock Cooking Cooling Saccharification Cooling Yeast PropagationFermentation Beer Stripping Beer Rectification Dehydration Denature Storage & Transportation Steam Cooling Water Alpha Amylase Enzyme Gluco Amylase Enzyme Yeast Cooling Water Steam Cooling Water Steam Natural Gasoline Rust Inhibitor 190 Proof 200 Proof Cooling Water CO2 Non volatiles Ethanol Production

8 Characteristics of Ethanol Ethanol is produced by fermenting corn, conversion of corn starch into ethanol –Sophisticated grain handling equipment present at ethanol production facilities –Co-products from ethanol production include distillers dried grains, a high protein animal feed & CO2 Future feedstocks will expand to include corn cobs & stover, switchgrass, sugar cane

9 Characteristics of Denatured Fuel Ethanol Polar solvent Totally miscible in water Less toxic than gasoline/methanol Toxic compounds not present in ethanol Greatest hazard as motor fuel component is flammability –Wider flammable range than gasoline: 3% - 19% by volume in air

10 Characteristics of Ethanol In neat form, no visible smoke or visible flame In denatured form, little to no smoke & slight orange flame will be visible Ethanol & some ethanol-blends can conduct electricity Large amounts of water required to dilute ethanol to no longer support combustion

11 Chemical Properties Comparison PropertyGasolineDenatured Fuel Ethanol Flash Point-45 0 F-50F-50F Ignition Temp F689 0 F Specific Gravity 0.72 – Vapor Density Vapor Pressure mmHg4.5mmHg Boiling Point F F Flammable Range 1.4% - 7.6%3% - 19% Conductivity NoneGood Smoke CharacteristicsBlackNone - Slight SolubilityNoneHigh

12 Invisible Flames - Ethanol Thermal imaging

13 Activity 2.1: Comparison of Gasoline and Ethanol Purpose: –To allow participants to discuss the differences & similarities in the chemical & physical properties of ethanol & gasoline.

14 Characteristics of Ethanol-Blended Fuels Ethanol increases the ability of gasoline to burn cleaner: –Lower emissions from unburned hydrocarbons Water contamination of ethanol gasoline fuel blends may cause phase separation: –Phase separation will introduce a water layer in the bottom that consists of water & ethanol –All hydrocarbon gasoline will remain in the top layer

15 Characteristics of Ethanol-Blended Fuels Water contamination of ethanol gasoline fuel blends may cause phase separation: –Gasoline floating on layer of ethanol/water solution –Resulting ethanol/water solution still flammable

16 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

17 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 smoke as the hydrocarbon burns off leaving only the ethanol burning

18 Activity 2.2: Definitions Purpose: –To allow participants to identify the definitions related to ethanol & ethanol-blended fuels.

19 Worksheet 2.2: Definitions Polar solvent Oleophilic Toxicity Ethanol Boiling point Vapor density Flammable range –Upper explosive limit (UEL) –Lower explosive limit (LEL) Hydrophilic –Water miscible Flash point Combustible liquid Flammable liquid Hydrocarbon Hydrophobic –Non-water miscible Specific gravity Auto-ignition temperature

20 Summary Ethanol is a polar solvent, miscible with water, & flammable Higher content of ethanol, less visible black smoke content, & orange flame production Blend of gasoline & ethanol can easily go unnoticed by emergency responders: –Ethanol will be last fuel to burn –Ethanol can burn without visible smoke