Driving on Biodiesel

Volume 1 Issue 1 - Diesel Articles

Article Index
Driving on Biodiesel
What is Biodiesel?
Biodiesel Versus Raw Vegetable Oil
Benefits of Using Biodiesel
Availability of Biodiesel
All Pages

With fuel pump prices above $3.50 a gallon, nearly everybody has become interested in breaking America’s addiction to oil. While hybrids are gaining popularity and hydrogen-powered fuel cells sound like a cool, futuristic idea, millions of people could benefit, right now, by choosing to use biodiesel in the vehicles they are already driving.

Biodiesel is a clean burning, alternative fuel produced from domestic renewable resources, such as vegetable oils and animal fats. Biodiesel contains no petroleum, but it can be blended at any level with petroleum diesel to create a biodiesel blend. It can be used in diesel engines with little or no modifications. It is simple to use, biodegradable, nontoxic, and essentially free of sulfur and aromatics.

Biodiesel produces less carbon monoxide, hydrocarbons and particulate matter than regular diesel does. By reducing tailpipe emissions, biodiesel is better for the environment.

Because it’s a renewable fuel, biodiesel also helps reduce global warming,. Most of the carbon generated when the fuel is burned is offset by the crops used to make the fuel when they are grown.

Since most of our biodiesel is produced here in the U.S. from plant oils grown by American farmers, it reduces reliance on imported petroleum and crude oil from countries that are politically unstable and often hostile towards the U.S.

Biodiesel is becoming more readily available across the country. Many of the same stations where we are used to filling up on traditional diesel are beginning to offer customers the option of refueling with biodiesel blends, such as B2, B5 or B20, which contain 2%, 5% and 20% biodiesel respectively.

The most common blend currently is B20hat’s 20% biodiesel and 80% petroleum diesel. However, lower blends are also becoming more popular as a way to restore lubricity in ultra low sulfur diesel. According to the National Renewable Energy Laboratory, as little as 2% biodiesel, blended with the balance of petrodiesel, can restore lubricity in ultra low sulfur diesel.

What is Biodiesel?

Biodiesel is made through a chemical process called transesterification in which the glycerin is separated from the fat or vegetable oil. The process results in methyl esters, the chemical name for biodiesel, and glycerin – a valuable by-product, which has hundreds of uses such as making cosmetics, drugs and food products.

One major advantage of biodiesel is that it can be made from numerous natural resources. In the U.S., soybeans are the primary feedstock, but in other parts of the world, canola, rapeseed, coconut, and other plant oils are being used. Biodiesel can also be made from recycled cooking oils and animal fats.

The formal definition of biodiesel, as recognized by the American Society for Testing and Materials International (ASTM), is, “mono-alkyl esters of long chain fatty acids derived from vegetable oils or animal fats, which conform to ASTM D 6751 specifications for use in diesel engines.”

This tight technical definition for biodiesel was needed to secure vehicle, engine and fuel injection equipment companies’ support for biodiesel and provide a legal definition for federal and state statute.

The current ASTM specification for biodiesel was first approved in December 2001. This standard covers pure biodiesel (B100), for blending with petrodiesel in levels up to 20% by volume (B20). ASTM members are currently working on revisions to ASTM D 6751 and a new specification for biodiesel blends from B6 to B20.

Changes to the ASTM D 6751 spec have been made to ensure compatibility between the biodiesel, new ultra low sulfur diesel, and new engine and after-treatment technology mandated by the EPA.

Nearly every Original Equipment Manufacturer (OEM) approves the use of up to 5% biodiesel (B5), when blended with diesel fuel that meets its appropriate specification as found in ASTM D 975. In most cases, OEMs will agree that blends up to 20% (B20) will cause no detriment to vehicle performance or engine durability. In either case, no OEM specifically states that using biodiesel blends above 5% will void their warranty.

Biodiesel Versus Raw Vegetable Oil

All biodiesel sources contain fat in some form. However, it is not the same thing as raw vegetable oil. The use of raw, unprocessed vegetable oils or animal fats in diesel engines can have significant adverse effects and should not be used in diesel engines. For example, the higher viscosity and chemical composition of unprocessed oils and fats have been shown to cause problems in a number of areas such as:

  • Piston ring sticking;
  • Injector, combustion chamber and fuel system deposits;
  • Reduced power and fuel economy; and,
  • Increased exhaust emissions.

Any or all of these conditions may result in reduced engine life, increased maintenance costs, or catastrophic engine failure. Because these problems are attributable to the fuel and are not defects in parts or workmanship, repairs would not likely be covered by the manufacturers’ warranty.

Benefits of Using Biodiesel

Biodiesel is the only alternative fuel to voluntarily perform EPA Tier I and Tier II testing to quantify emission characteristics and health effects. That study found that B20 reduced total hydrocarbons by up to 30%, carbon monoxide up to 20%, and total particulate matter up to 15%. Biodiesel also has excellent lubricity properties and is typically low in sulfur content, making it compatible with the new generation of diesel fuels required by the EPA.

Typically, emissions of nitrogen oxides are either slightly reduced or slightly increased depending on the duty cycle of the engine and testing methods used. With the new after-treatment devices required to meet new EPA diesel emissions requirements, engine out emissions are likely to have a negligible effect on NOx tailpipe emissions.

Biodiesel can also help meet national goals for the reduction of greenhouse gases. As a renewable fuel derived from organic materials, biodiesel and biodiesel blends reduce the net amount of carbon dioxide in the biosphere.

A study by the US Department of Energy has found that biodiesel production and use produces 78.5% less CO2 emissions compared to petroleum diesel. Carbon dioxide is “taken up” by the annual production of crops such as soybeans and then released when vegetable oil based biodiesel combusts. Also, biodiesel is safer for people to breathe. Biodiesel emissions have decreased levels of all potential cancer causing compounds, called polycyclic aromatic hydrocarbons.

Biodiesel also helps preserve and protect natural resources. For every one unit of energy needed to produce biodiesel, 3.2 units of energy are gained. This is the highest energy balance of any fuel. Because of this high energy balance and since it is domestically produced, biodiesel use can greatly contribute to domestic energy security.

Biodiesel is nontoxic and biodegradable. Biodiesel is ten times less toxic than table salt and biodegrades as fast as dextrose, a test sugar.

Ready, Set… Biodiesel

Before switching to biodiesel, here are some things you need to know:

Ensure the biodiesel meets the ASTM specification for pure biodiesel (ASTM D 6751) before blending with petrodiesel.

The specification for biodiesel is designed to ensure that consumers will not experience operational problems from the fuel’s use. Make sure that the fuel supplier will warrant the fact that the fuel meets specification. Quality fuel will provide the consumer with improved air quality and enhanced operability. Purchase fuel only from a reputable source, such as companies that are accredited under the BQ-9000 biodiesel quality program.

BQ-9000 is a cooperative and voluntary program for biodiesel producers and marketers. The program is a unique combination of the ASTM standard for biodiesel and a quality systems program that includes storage, sampling, testing, blending, shipping, distribution, and fuel management practices.

Check fuel filters on the vehicles and in the delivery system frequently upon initial biodiesel use, and change them as necessary.

Biodiesel has excellent cleansing properties. In some cases, the use of petrodiesel, especially #2 petrodiesel, leaves a deposit in the bottom of fuel lines, tanks, and delivery systems. The use of biodiesel and some biodiesel blends can dissolve this sediment and result in the need to change filters more frequently until the whole system has been cleaned of the deposits left by the petrodiesel. This same phenomenon has been observed when switching from #2 to #1 petrodiesel.

Be aware of biodiesel’s cold weather properties and take precautions, as with #2 petrodiesel use, in cold weather.

A 20 percent blend of biodiesel with petrodiesel usually raises the cold weather properties 2 to 10°F. In most cases, this has not been an issue. Twenty percent biodiesel blends have been used in the upper Wisconsin area and in Iowa during -25°F weather without issues. Solutions to biodiesel winter operability problems are the same as those used with conventional #2 petrodiesel. Options include: using a pour point depressant; blending with #1 diesel; using engine block or fuel filter heaters on the engine; or storing the vehicles near or in a building.

Be aware of biodiesel’s compatibility with engine components.

The switch to low sulfur diesel fuel has caused most OEMs to switch to components suitable for use with biodiesel, but users should contact their OEM for specific information. In general, pure biodiesel will soften and degrade certain types of elastomers and natural rubber compounds over time. Using high percent blends can impact fuel system components, such as fuel hoses and fuel pump seals, which contain elastomer compounds incompatible with biodiesel. Manufacturers recommend that natural or butyl rubbers not be allowed to come in contact with pure biodiesel. Blends of B20 or lower have not exhibited elastomer degradation and need no changes. If a fuel system does contain these materials and users wish to fuel with blends over B20, replacement with compatible elastomers is recommended.

Use stored biodiesel within six months.

All fuels, including #2 and #1 petrodiesel, have a shelf life. This is also true with biodiesel and biodiesel blends. Industry experts recommend that biodiesel be used within six months of purchase to ensure that the quality of the fuel is maintained. Storage time does not impact biodiesel distribution given biodiesel’s production logistics. Biodiesel is generally not stored for long periods of time. Production levels and rates are established to meet demand, similar to just in time inventory methods.

Availability of Biodiesel

There are more than 165 biodiesel plants in operation, with many more planned. More than 1,800 petroleum distributors make biodiesel available to farmers and other consumers. And, more than 1,250 retail pumps now make the fuel available to the public.

Biodiesel is available throughout the U.S. A list of registered fuel suppliers as well as petroleum distributors and retail fueling sites is maintained through the National Biodiesel Board. This list is available at www.biodiesel.org

Hundreds of major fleets are using biodiesel, including all branches of the U.S. military, Yellowstone National Park, NASA, several state departments of transportation, major public utility fleets such as Florida Power & Light, cities such as San Francisco and Ann Arbor, Mich., and more than 200 school districts.

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Comments (1)add comment

duncdunc76 said:

Curious about running WVO in a 1994 suburban 6.5
Hello out there im brand new to MaxxTorque but have been a familiar fan of Heath diesel info and am so happy to have such resources available. I am a resturant owner in Indiana and about a year and a half ago i purchased a 1994 6.5 suburban in hopes of converting it to run on waste vegetable oil. The truck has some injector pump problems and my project has been mostly research thus far but knowledge has been compiling thanks to sites like this one. Ive gotten quite a bit of info on wvo conversions and the +'s and -'s of running wvo in a diesel, however in my research i would have to say all sources are not created equal and i would love to get some MaxxTorque feedback/advice from anyone involved or interested in the subject. Thanks in advance for any feedback/advice. I am quite the outdoor enthusiest in addition to being a diesel enthusiest and dream of getting my 6.5 suburban in exploring shape so i can use her to tackle another dream of mine which is to see every national park before i die. Again thanks for any info and for a great resource like MaxxTorque!
July 05, 2012
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