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January/February 2009

a non-petroleum fuelASTM Sets the Standard for Biodiesel

Committee D02 on Petroleum Products and Lubricants has produced a set of standards for a non-petroleum fuel: biodiesel.

ASTM International is fueling the use of an alternate, renewable energy source with the October 2008 publication of new and revised specifications for biodiesel.

The new standards give the industry a valuable tool — recognized and accepted by buyers and sellers alike — that ensures product quality and performance by setting clearly defined parameters. They are the result of collaboration on the part of Subcommittee D02.E0 on Burner, Diesel, Non-Aviation Gas Turbine and Marine Fuels, whose members include representatives from petroleum refineries, automakers, engine manufacturers, biodiesel producers, academia and others from around the world.

“It took a lot of cooperation to reach consensus on the specifications,” says Steve Howell, president of MARC-IV Consulting, Kearney, Mo., and chair of ASTM’s biodiesel task force. “We used live electronic tools to significantly speed up the amount of time it took us to develop the standard without sacrificing any of the value of the discussion, deliberation and information sharing required to pass an ASTM specification.”

Biodiesel Defined

Biodiesel is made of “mono-alkyl esters of long chain fatty acids derived from vegetable oils or animals fats.” In layman’s terms, it is a clean-burning alternative fuel made from fat or oil (such as soybean or palm oil) that has been chemically processed to remove glycerin. The term biodiesel refers to the pure fuel – called B100 – which has been designated as an alternative fuel by the U.S. Departments of Energy and Transportation. B100 can be used in its pure state but is more commonly used as an additive for conventional diesel fuel.

According to the National Biodiesel Board, more than 170 companies in the United States are actively marketing biodiesel and developing manufacturing plants with a potential production capacity of approximately 2.24 billion gallons per year.

Some benefits attributed to biodiesel as a fuel include renewability, a reduction of greenhouse gases and other regulated emissions, and a reduced reliance on petroleum-based fuel. It can also be used in diesel engines without the need for modification.

The Standards

Subcommittee D02.E0 began work on the standards by building on the concept of a performance-based specification that would be feedstock- and process-neutral. The development of the blended fuel specifications began in 2001 after ASTM D6751, Standard Specification for Biodiesel Fuel Blend Stock (B100) for Middle Distillate Fuels, was published, using existing specifications as models.

“We were dealing with a new type of fuel that had some interesting properties,” says Steve Westbrook, staff scientist, Southwest Research Institute, San Antonio, Texas, and chair of Subcommittee D02.E0. “We had to start from scratch to make the specification describe not just an adequate fuel, but one that would be as trouble free as possible and function properly in its intended application.”

The new and revised standards are:

  • ASTM D6751-08 — revised to include the requirement of a cold soak filterability test that controls minor compounds and provides a more accurate reading of how the fuel will perform in cold weather conditions.
  • ASTM D975-08a, Specification for Diesel Fuel Oils (on- and off-road applications) — revised to allow for up to 5 percent biodiesel content. This allows B5 blends to be treated the same as conventional diesel for testing purposes.
  • ASTM D396-08b, Specification for Fuel Oils (home heating and boiler applications) — revised to allow for up to 5 percent biodiesel content. Like D975, this revision allows B5 blends to be treated the same as conventional fuel oil for testing purposes.
  • ASTM D7467-08, Specification for Diesel Fuel Oil, Biodiesel Blend (B6 to B20) ­— a newly created standard governing the properties of blends containing between 6 and 20 percent biodiesel for on- and off-road applications.

“These standards have been through the rigorous ASTM balloting process,” says Howell. “If you have a fuel that meets these standards, then you can be assured that it is fit for its purpose and is going to work well in your engine.”

Putting the Standards to Use

The D6751 suite of standards establishes a minimum level of quality so that the producers and users of biodiesel know what to expect from the product.

For the producers, the standards help provide a level playing field, says Randy Jennings, executive assistant, Tennessee Department of Agriculture, Nashville, Tenn. “The producers are aware that regulators are going to be visiting their production and storage facilities on a routine basis to take samples and test their product,” he says. “It’s important for them to know that if they want to produce biodiesel, then they have to meet the same requirements as everyone else.”

The standards also provide equipment manufacturers with a way to determine how the fuel will affect the performance and lifespan of their products. “For users such as the engine and component manufacturers, the standards are essential to their operation,” says Jennings. “They build the equipment, everything from the fuel injection, to filtering systems, to the overall design of the vehicle fuel and emissions systems. They have to know how the fuel will affect the components of the engine and related systems.”

“Manufacturers of engines and vehicles examine the effect of a fuel on durability and functionality to determine its compatibility with the engine and emissions systems and whether or not biodiesel blends or other fuels are acceptable for use with their products,” says Roger Gault, technical director, Engine Manufacturers Association, Chicago, Ill. “These standards serve as a benchmark that allows engine manufacturers to quantify their evaluation of a fuel and its compatibility with their product.”

“Without these standards, it would not be possible for manufacturers to warranty vehicles for use with blends up to B20,” says Chris Sidney, Chrysler Regulatory Affairs, Auburn Hills, Mich. “Equipment owners could risk damaging their vehicles with poor quality fuel and at the same time void the warranty on their vehicles. The new standards provide a basis for creating a reliable fuel supply for biodiesel.”

The standards also help to support the growth of the biodiesel market, which in turn create more opportunities for economic development and energy independence, says Sidney. Because the standards for blends up to 20 percent are performance-based and feedstock- and process-neutral, they open the door for increased research and development into more efficient ways of producing renewable diesel fuels.

Whether it is for a fleet of vehicles or a single truck or tractor, people feel more comfortable using a new fuel if the engine and vehicle manufacturers approve the use of those fuels in their products. The expectation is that the fuel put into the vehicle or equipment will not create problems such as unacceptable performance or premature failure.

Local and Global Acceptance

The U.S. government has adopted the ASTM standards for biodiesel so the D6751 suite of standards continues to grow in prominence. The Energy Independence and Security Act of 2007 mandates the use of D6751 and requires fuel producers to use at least 36 billion gallons of renewable fuel a year by 2022. To date, approximately 35 states, including Minnesota and Tennessee, require their biodiesel fuel to meet ASTM standards and will be incorporating the new revisions into their laws. Most of the remaining states use parts of the standards in their own specifications.

D6751 is also used wholly or in parts in many countries around the world including Brazil, Malaysia, Greece, Singapore and the Philippines. The international appeal is due at least in part to ASTM’s open voting process, notes Howell. “We have many countries weighing in and voting on the specifications. Because they have a say in the process they feel confident that the specifications aren’t set up to limit trade, or are based on the whims or politics of any individual country. It ends up being a much more robust, more trade-neutral set of specifications. When people look at an ASTM standard they know it’s solid — it’s the gold standard for fuels around the world.”

As time goes on the standards will continue to evolve, says Howell. “With new engine designs and potentially new feedstocks coming down the road, we’ll be looking at new test methods and better ways to analyze the product and improve the specifications.”

Biodiesel Web Portal

For additional information about the D6751 suite of biodiesel standards, click here. This subscription-based Web portal provides “one-stop shopping for the latest biodiesel fuel standards,” offering direct links to the specifications and related materials including ASTM sources and government regulations. The portal allows users to compare and revise documents, make notes and annotations to the standards, and share their thoughts and comments with other users.

Kessel Nelson is a freelance writer whose work has appeared in national and international publications, covering subjects ranging from art to energy to schizophrenia. He has a B.A. in history from the University of Pennsylvania, and he spends his time between Philadelphia and New York City.