Alternative Fuels, Part 2Posted 9/11/2007
By Jim Linder
Our first article discussed alternative fuels and broke down a description of each. We closed our discussion regarding the term "energy balance." In our second section, we will discuss energy balance and expand on each alternative fuel type.
As previously stated, the energy balance when compared to fuel production is considered to be the energy produced by 1 kilogram of the fuel (i.e., biodiesel, ethanol, etc.) and the energy necessary to produce it (transportation, refining, etc.).
The net energy gain is defined as the difference between the energy in the product (output energy) and the energy needed to produce the product (input energy). Many discuss this energy balance using energy returned on energy invested (EROEI), and the actual ratio is expressed as the amount of usable energy acquired from a particular energy resource to the amount of energy expended to obtain that energy resource. When the EROEI of a resource is equal to or lower than one, that energy source becomes an "energy sink," and can no longer be used as a primary source of energy. As long as the energy balance doesn't go negative, it's considered a good alternative.
Crude oil, when found in the 1920s, gained 100 barrels of oil for every single barrel used, for an EROEI of 100 to 1. Today, this ratio is considered to be 3 to 1 in the United States. Biodiesel leads the hunt at 5 to 1 and ethanol is the lowest at 1.3 to 1.
Let's look at the alternatives. For the sake of discussion, I have condensed our list down to four families of alternative fuels. They are:
Alcohols: Ethanol and methanol
Gases: Liquefied petroleum gas (LPG) under low pressure and compressed natural gas (CNG under high pressure)
Biodiesel: plant oil, animal fat
Electric: battery and hybrid
When gasoline companies, under federal regulations, removed lead from gasoline, other methods had to be developed to help maintain the antiknock properties of gasoline.
Octane improvers are usually grouped into three areas:
Note: MMT has been proven harmful to catalytic converters and spark plugs and is used in some parts store octane improvers and fuels sold in Canada. The spark plug will show a rust ring on the porcelain if MMT has been used as an additive.
Oxygenated fuels, used in emission non-attainment areas for emissions control, contain oxygen in the molecule of fuel itself. Examples of oxygenated fuels include methanol, ethanol, methyl tertiary butyl ether (MTBE), tertiary-amyl methyl ether (TAME), and ethyl tertiary butyl ether (ETBE). The most common blend used today is ethanol.
What Is Ethanol?
Ethanol (ethyl alcohol, grain alcohol, EtOH) is a clear, colorless liquid. In dilute aqueous solution, it has a somewhat sweet flavor, but in more concentrated solutions it has a burning taste. Ethanol (CH3 CH2 OH) is made up of a group of chemical compounds whose molecules contain a hydroxyl group, -OH, bonded to a carbon atom. Ethanol made from cellulosic biomass materials instead of traditional feedstocks (starch crops) is called bioethanol.
Blends of at least 85 percent ethanol are considered alternative fuels under the Energy Policy Act of 1992. E85, a blend of 85 percent ethanol and 15 percent gasoline, is used in flexible fuel vehicles (FFVs) that are currently offered by most major auto manufacturers. FFVs can run on gasoline, E85, or any combination of the two and qualify as alternative fuel vehicles under Environmental Protection Agency (EPA) regulations.
How Is Ethanol Made?
Ethanol can be produced from any biological feedstocks that contain appreciable amounts of sugar or materials that can be converted into sugar such as starch or cellulose. Sugar beets and sugar cane are examples of feedstocks that contain sugar. Corn contains starch that can be easily converted into sugar. A significant percentage of trees and grasses are made up of cellulose, which can also be converted to sugar, although with more difficulty than required to convert starch.
Ethanol is also made from a wet-milling process. Many larger ethanol producers use this process, which also yields products such as high-fructose corn sweetener.
Today's ethanol is produced using corn, and an increased demand for ethanol means an additional market for corn, a more stable and profitable farming industry, and an increased level of energy security for our nation.
Alcohol Additives: The good, bad and ugly
Most of us technicians have not-so-fond memories of the added 10 percent alcohol additive in the late '70s and early '80s, which resulted in carb parts degradation, rubber lines swelling and driveability problems. Car parts were just not designed to use alcohol!
Today's vehicles are designed (or at least some) to use these new fuels but new problems exist as well.
The bad (and maybe ugly):
Note: The largest problem we see with ethanol products - especially the E85 blend - is that many consumers are putting it in the older vehicles. This may (and usually does) create a problem with system contamination and overall driveability.
Methanol, also known as methyl alcohol or wood alcohol, is a chemical compound made up of one carbon atom, four hydrogen atoms and one oxygen atom.
Methanol is a light, volatile, colorless, tasteless, flammable, poisonous liquid with a very faint odor. It is used as an antifreeze, solvent, and fuel, and to denature ethanol. Methanol burns in air forming CO2 (carbon dioxide) and H2O (water). A methanol flame is almost colorless. Because of its poisonous properties, methanol is also used to denature ethanol. Methanol is often called wood alcohol because it was once produced chiefly as a byproduct of the destructive distillation of wood.
The biggest source of methanol in the United States is coal. Using a simple reaction between coal and steam, a gas mixture called syn-gas (synthesis gas) is formed.
The components of this mixture are carbon monoxide and hydrogen, which through an additional chemical reaction, are converted to methanol. Methanol is toxic and can cause blindness and death. It can enter the body by ingestion, inhalation, or absorption through the skin. Dangerous doses will build up if a person is regularly exposed to fumes or handles liquid without skin protection. If methanol has been ingested, a doctor should be contacted immediately. The usual fatal dose is 4 oz. (100-125 mL).
Some flexible fuel vehicles are designed to operate on 85 percent methanol and 15 percent gasoline. Methanol is corrosive and requires that the fuel system components be constructed of stainless steel and other alcohol-resistant rubber and plastic components. The heat content of M-85 is about 60 percent of that of gasoline. Note: The use of M-85 has mainly been with large fleets and companies as refueling stations are not easily found.
Biodiesel is a domestically produced, renewable fuel that can be manufactured from vegetable oils, animal fats or recycled restaurant greases. Biodiesel is safe, biodegradable, and reduces serious air pollutants such as particulate matter (PM), carbon monoxide, and hydrocarbons. Biodiesel is defined as mono-alkyl esters of long-chain fatty acids derived from vegetable oils or animal fats, which conform to ASTM D6751 specifications for use in diesel engines. Biodiesel refers to the pure fuel before blending with diesel fuel.
Biodiesel blends are denoted as "BXX," with "XX" representing the percentage of biodiesel contained in the blend (for example, B20 is 20 percent biodiesel, 80 percent petroleum diesel). Blends of 20 percent biodiesel with 80 percent petroleum diesel (B20) can generally be used in unmodified diesel engines; however, users should consult their OEM and engine warranty statement.
Biodiesel has several characteristics, including the following:
So far have we found the perfect alternative to gasoline? I think not! Gasoline continues to lead the way. The November issue of AutoInc. will contain our final discussion of alternative fuels. Part three will discuss electric cars, hybrids and the gases LPG and CNG.
Editor's Note: Don't miss a three-hour class discussion (to include case studies of each fuel) at the Congress of Automotive Repair and Service show in Las Vegas in November. For details, visit www.CARSonline.org.
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