Curtis Wright, Biotane Fuels division manager, has a special affinity for fried foods, but he doesn't have to worry about the calories because he is collecting and then converting used cooking oils into oxygenated diesel — known to trucking companies as biodiesel.

Biotane Fuels, a division of Imperial Western Products Company Inc, Coachella, California, has been developing biodiesel production technology and educating consumers about the benefits of the clean-burning fuel since 2000.

“We primarily collect used cooking oils from restaurants for the process, but we also use oils from soybeans, cottonseeds, sunflowers, jatropha (a succulent plant oil obtained from Mexico), and algae,” says Wright. “We've looked at about anything that has any oil in it. It is important to process products that are inexpensive, harmless to the food chain, and good for the environment. That's the key.”

If converting used vegetable oils into biodiesel sounds like a process that could be conducted in the garage with a kitchen sieve and a couple of buckets, think again. Wright, a graduate of the University of Texas at Austin with a bachelor's degree in biochemistry and a master's degree in petroleum engineering, spent several years in researching, designing, and developing the Coachella biodiesel plant. The facility went online in 2001 and today has the capability of producing 12 million gallons of product annually.

Process begins

The process begins with collecting used vegetable oils and animal fats from restaurants and other food facilities in about a 250-mile radius of the plant. As one example of efficiency, Biotane currently is working with a company to collect its used cooking oil and in return provide biodiesel for the company's fleet in what is a true closed-loop process. (Biotane operates tank trailers for collecting the oil and uses for-hire carriers, as well.)

The oils, fondly known in the industry as “yellow grease,” are pumped into a reactor and mixed with methanol and a catalyst. The methanol molecule combines with the fatty acids in the fats and oils to form a methyl ester, or biodiesel. When this reaction occurs, glycerol is split from the fats and oil with the resulting mixture containing biodiesel, glycerol, and traces of catalyst, soaps, and alcohol. When the glycerol and other byproducts are removed and the methanol evaporated, the remaining product is biodiesel (B100). An antioxidant may be added to extend shelf life. The process typically is completed in about 24 hours.

In order for biodiesel to be sold, receive any government incentives, or tax credits, the fuel must meet American Society for Standards and Materials (ASTM) D6751 specifications. Although ASTM D6751 is not dependent on any particular feedstock or production process, changes in either can affect the finished biodiesel properties.

“For example, feedstocks that contain a high percentage of saturated fatty acids, such as palm oil or tallow, will make a biodiesel with higher cetane value and a higher cloud point,” says Wright. “The process used to make this biodiesel will not affect these properties, however production processes will determine how low the free and total glycerol content is — and other parameters such as flash point, water, sediment, and clarity.”

Quality assurance

Imperial Western Products holds BQ-9000 accreditation. This is a quality assurance program that includes procedures for fuel storage, handling, and management aimed at ensuring fuel quality throughout the distribution system. The program is designed to create a comprehensive quality system whereby fuel is consistently produced in accordance with ASTM specifications, according to the National Biodiesel Board.

At the Biotane plant, a minimum of 12 tests are conducted before the product is certified. “We maintain close inspection at eight different check points through each stage of production,” Wright notes.

Every batch of Biotane undergoes a strict quality control analysis by the laboratory onsite, as well as by independent laboratories. Not only does the company focus on production quality at a micro level, it is largely involved on a macro level too.

“The product undergoes a test to determine the cloud point,” says Wright. “Cloud point is a very important parameter as it gives an indication of the temperature at which biodiesel molecules will begin to crystallize and drop out of solution.

“While cloud point is an important parameter, there are other cold flow tests that measure the performance of biodiesel. New to ASTM D6751 is the cold soak filtration test, a test that takes 16 hours to complete and measures the filterability of biodiesel after it has been frozen and thawed. That test gives further indications of the cold weather performance of the product. In addition to finished product testing, we evaluate all incoming oils, methanol, and other products used in the process.”

Storage procedures

When product receives final testing during processing, it is pumped into storage tanks. Thirty storage tanks are used for finished product and other materials needed for the process. Storage tanks range in capacity from 10,000 gallons to 30,000 gallons.

However, even in storage, the testing hasn't ended. Product is continually sampled for purity — the final test completed when product is loaded into a tank trailer for distribution.

“Biodiesel should be stored in systems that are clean and free of moisture and constructed of materials that are compatible with biodiesel,” says Wright. “Because biodiesel has more of an affinity for water than petroleum diesel, it is important to keep storage systems free of water. Also, because biodiesel is more biodegradable than petroleum diesel, biodiesel is more likely to become contaminated with microbiological agents if contacted with water.”

Splash blending

Biotane provides B100 for distribution and also will splash blend the product with petroleum diesel on site. Blended concentrations typically range from 5% (B5) to 20% (B20).

“Because biodiesel is slightly heavier than petroleum diesel, it is important to make sure that the biodiesel and petroleum diesel are well-mixed when blended,” Wright says. “Temperature differences between the two liquids can make blending more difficult. Splash blending into a tank trailer, which is subsequently unloaded into another tank, is generally effective to ensure good mixing. It is not recommended to pump at low volume into a large storage tanks, such as gravity draining into a large underground storage tank.”

Wright adds that when biodiesel and petroleum diesel have been properly mixed, the two will never separate or come unblended. After the product is released for shipment, about three tank trailers per day are loaded, and about the same number arrive hauling products used in the processing. Biotane transports product to the California Department of Transportation and local ports. In addition, the company and its distributors deliver product to fleets, manufacturing facilities, and public entities.

Another essential element in the product's process is maintaining an environmentally friendly facility. To that end, Biotane emphasizes recycling as much as possible and careful handling of waste and byproducts. Recovered glycerol not used in the biodiesel processing is transported to other facilities for their use. Wastewater that is not vaporized is neutralized and recycled. Equipment also is available to recover methanol.

Even with an annual production capacity of 12 million gallons by Biotane and 500 million gallons industrywide, Wright notes that the growing demand outdistances supply. In order to meet these challenges, Biotane is continuing to expand production facilities and distribution networks by forming strategic alliances at home and abroad.

Certain federal tax breaks have helped boost expansion, but they were slated to expire this year. However, the tax break rules were extended to December 2009 when they were included in the financial bailout bill approved by Congress in October.

Wright points out that California doesn't consider biodiesel as an alternative fuel because nitrogen oxide (NOx) is not reduced. Nevertheless, particulate, sulfur, and volatile organic compound (VOC) output is reduced. Other states and the Environmental Protection Agency recognize biodiesel as an alternative fuel, he says.

Biodiesel can be used as an additive to improve lubricity in ultra low sulfur diesel. The product can be used in any compression diesel engine with no modifications and is simple to use, biodegradable, non-toxic, and essentially free of sulfur and aromatics.

With those product advantages, including the environmental friendly aspects, the market will be growing as the issues ameliorate — and Biotane will be there to meet the needs.