Gasoline is a refined product of petroleum crude oil, consisting of various ingredients, primarily hydrocarbons...
Gasoline derived from petroleum usually contains hundreds of ingredients (150-1000 different compounds), and ethanol is just one of many.
Gasoline specifications and ingredients are usually determined by government and environmental regulations. Specifications and test methods can be found in publications SAE (Society of Automotive Engineers), and ASTM (American Society for Testing Materials).
The ability to evaporate (volatility) determines which hydrocarbons can be used in gas. Because crude petroleum consists of hydrocarbons both more and less volatile than gasoline, a process called distillation and refining is used to produce fuel.
What gasoline may contain:
Hydrocarbons: Compounds consisting of hydrogen and carbon atoms - Hydrocarbons ( HCs ) are any molecules that just contain hydrogen and carbon, both of which are fuel molecules that can be burnt (oxidised) to form water (H2O) or carbon dioxide (CO2).
Saturated hydrocarbons (aka paraffins, alkanes) are the major component of gasolines.
Parafins or alkanes: Examples - Isoparafins, n-butane, isooctane;
Olefins or alkenes: Examples -1-pentene, 2-methyl-2-butene;
Cycloalkanes or Naphthenes: Examples - Cyclopentane, cyclohexane;
Oxygenators: Oxygenates are just preused hydrocarbons. They contain oxygen, and are good substitutes for aromatics, and may also reduce the smog-forming tendencies of the exhaust gases. Examples = Ethanol (EtOH), Methanol (MeOH), methyl tertiary butyl ether (MTBE), tertiary amyl methyl ether (TAME), ethyl tertiary butyl ether (ETBE);
The lack of public warning prior to the widespread distribution of E-10, and the sudden occurrence of engine problems/malfunctions/damage when E10 fuel is being used improperly (or used in engines not designed for alcohol fuels), has resulted in consumer anger.
Some people are still unaware that ethanol blend fuels, E10 gasoline is now being sold at most public gas stations.
Ethanol advantages: Ethanol is safer for the environment (compared to MTBE and petroleum), helps reduce our dependence on foreign oil imports, is a cleaner burning fuel, supports the US Farming Industry (made from corn and grains). More ethanol benefits.
Ethanol gasoline fuel is commonly called E10,
E85, corn fuel, alcohol fuel and reformulated, renewable fuel and gas.
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About Gasoline and Ethanol Alcohol Fuel Blends - Reformulated, Renewable Fuels.
"E10 Gasoline" is a conventional gasoline, (now found at most public pumps), that contains up to 10% ethanol alcohol; "E85" is an alternative fuel that contains about 85% ethanol alcohol.
Ethanol Fuel - What is it?
The chemical name of ETHANOL is C2H5OH. Ethanol fuel usually refers to a gasoline that contains ethyl alcohol. Ethanol is an alcohol, made from corn, grains, sugar and other common farm produce. Flex fuel and E85 is a gasoline containing 85% ethanol. E10 contains 10% or less ethanol.
Ethanol has many uses in the fuel industry...
It can be an oxygenator (E10);
A primary type of gasoline (E100 and 85% of E85);
An octane enhancer;
A cleanser (solvent, degreaser),
A water absorber...And much more.
Ethanol and other primary alcohols are commonly included in gas additive products, due to the actions they can accomplish - Examples: Octane enhancers, fuel system cleaners, detergents, carbon deposit removers, etc.
When used as an oxygenator, 10% content is the legal maximum content for ethanol in most states and countries.
When used as a primary fuel, the engine must be specifically designed to run on the high alcohol level E.G. Flex Fuel Vehicles.
Racing vehicles are often designed (modified) to accept high levels of ethanol (usually between 72% to 86%).
The owners of this vehicles used for racing (cars, boats) know how to properly manage and store alcohol fuel to avoid negative effects on engine parts. (rusting, piston or other fuel system damage, etc.)
Compared to conventional (non-alcohol) gasoline, E10 and E85 (ethanol blend fuels), will absorb much more water, and at a faster rate.
Ethanol Energy and Fuel Efficiency:
One drawback of E10 and E85 fuel is it generates less energy than fuels without alcohol.
E85 generates only about 75 percent as much power as a gallon of gasoline. That means that ethanol would have to be roughly 25 percent cheaper per gallon to be a bargain for consumers, which it is not true today.
- Fuels containing ethanol release less energy compared to non-alcohol fuels, and get a lower MPG rating, (2-40% less miles per gallon).
- Ethanol alcohol, an excellent solvent, can dissolve fuel system parts, rubbers, plastic, certain fiberglass, and even aluminum.
- The rubber that is used in fuel system parts, such as seals and hoses, may shrink, swell, or lose strength when exposed to ethanol reformulated gasoline.
In recent years, there have been several reports of dangerously high levels of ethanol (over 10%) in E10 fuel tested at the pumps. This has caused whay has been termed "the ethanol scare".
Fuel Testers recommends testing gasoline for alcohol at the pumps before buying. Alcohol Fuel Test Kits will assure gas contains 10 % or less ethanol. See Product Information.
E10, Ethanol has dramatically changed fuel system management and precautions...
Ethanol's Water Absorbing Qualities and High Risk for Gas Contamination:
- Ethanol is hygroscopic (will absorb water), and is an excellent solvent (dissolves materials).
- Ethanol is added locally to gasoline at the pumps, after the gas is produced and delivered from the major gas refineries because of the risk of water contamination when traveling through the pipelines.
- 10% ethanol gasoline can dissolve 50 times more water than conventional non-alcohol gasoline.
- Unlike MTBE, (previously used to oxygenate fuel), water will actually dissolve in an ethanol blended fuel and phase separation occurs much sooner.
- Phase separation occurs when only 0.5% water or 3.8 teaspoons water per gallon is absorbed into E10 gas.
At 70 degrees Fahrenheit, conventional (non-alcohol) gasoline can dissolve up to 150 parts per million (ppm) water.
The situation is different for gasoline oxygenated with 10 % volume ethanol...
The ethanol blend can dissolve much more water, up to 6000-7000 ppm.
When this blend is cooled, both the water and some of the ethanol become insoluble.
Phase separation of gasoline occurs when too much water is absorbed into petroleum gasoline.
Two and sometimes 3 layers of liquid are visible. An upper ethanol-deficient gasoline layer and a lower ethanol-rich (up to 75% ethanol) water layer.
Phase seperation occurs because ethanol is completely soluble in water but only marginally soluble in hydrocarbons...
After phase separation, the gasoline layer will have a lower octane number and may knock in an engine. The fuel also is less volatile.
Running an engine on the phase-separated fuel can cause serious engine difficulty and problems.
Ethanol fuel expires in 90 days.
At around 90-100 days, under ideal conditions (mid-temperature and low humidity), ethanol blend fuels will enter phase separation (contaminated gas). One effect of phase separated fuel is that the octane will drop as much as 3 points or more. See octane.
Due to ethanol's affinity for water, nowadays engine manufacturers recommend refilling/replacing your fuel every 14 to 30 days.
Water removal from E10 fuel requires a complete understanding of how water and ethanol chemically join.