September 22, 2009

Soybean oil blend works well as fuel for home furnaces

Klein Ileleji
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A blend of degummed soybean oil and No. 2 fuel oil can be used as an alternative heating fuel and reduce sulfur emissions, according to a Purdue University scientist.

Klein Ileleji, an assistant professor of agricultural and biological engineering, tested blends of 20 percent, 50 percent and 100 percent degummed soybean oil – an unrefined and cheaper product to produce than soy methyl esters, commonly known as biodiesel – and found that the 20 percent blend didn't degrade a home furnace's parts or heat output. The only issue found with the 20 percent blend was a slight early degradation of the furnace's seals and gaskets, which manufacturers could fix by switching to a higher quality product. Ileleji's findings were reported in the recent early online version of the journal Fuel.

"You are going to reduce the sulfur emissions with degummed soybean oil. The things you should be worried about with a biofuel, such as the pour point temperature and heating ability, were not affected," Ileleji said. "You want to keep the properties of your No. 2 fuel oil, and at 20 percent degummed soybean oil, you would minimally affect those properties."

Removing gumming agents from soybean oil eliminates its harmful effects on fuel injection nozzles, gaskets and other parts, and creates a combustible biofuel. Like some other biofuels, its properties can be less desirable than traditional fuels. Ileleji's study showed that 100 percent degummed soybean oil and a 50 percent blend had reduced flashpoints, making them more difficult to ignite; reducing heat content; creating higher temperatures associated with cold filter plugging points; and leading to early degradation of seals and gaskets.

"Overall, using 20 percent degummed soybean oil, you can get by using existing furnace designs," Ileleji said. "You can use a 20 percent blend without changing your combustion system, and you will not be changing its performance. What you will be getting is the benefit of lower sulfur emissions, which is good for the environment."

Ileleji's work was a continuation of a project started by Harry Gibson, a retired Purdue professor of agricultural and biological engineering, and Gibson's graduate student, Bradley Kaufman. The Indiana Soybean Alliance and the Indiana United Soybean Board funded the research.

Ileleji said he is testing the degummed soybean blends with farm grain dryers to see if the biofuel could be used efficiently with those devices' burners.

Writer: Brian Wallheimer, 765-496-2050,

Source: Klein Ileleji, 765-494-1198,

Ag Communications: (765) 494-8415;
Steve Leer,
Agriculture News Page

Purdue researcher Klein Ileleji found that a 20 percent blend of degummed soybean oil performed well in home furnaces and reduced sulfur emissions. (Purdue Agricultural Communications photo/Tom Campbell)

A publication-quality photo is available at


Testing the Performance and Compatibility of Degummed Soybean Heating Oil Blends for Use in Residential Furnaces

 Teshome E. Jiru, Bradley G. Kaufman, Klein E. Ileleji, Daniel R. Ess, Harry G. Gibson and Dirk E. Maier

Degummed soybean heating oil (SHO) is a renewable energy resource, which can reduce dependence on foreign oil and create a new market for the soybean industry. This study demonstrated that SHO 20 (20% degummed soybean oil and 80% No. 2 fuel oil) is suitable for application in residential furnaces without modification. The tests conducted were: fuel properties, seal compatibility, long-term storage, and laboratory and field combustion. The physical property tests showed that the kinematic viscosity (0.0346 cm2/s) and the pour point of SHO 20 (−30°C) were within the ASTM requirement for No. 2 fuel oil; and the net heating value of SHO 20 (43.9 MJ/kg) was only 1–3% lower than the No. 2 fuel oil value (45.6 MJ/kg). Compatibility tests performed on the rubber seals and gasket materials (Nitrile and Viton) found in typical heating fuel pump systems indicated that the tensile strength and hardness values were not significantly affected by SHO blends when compared with No. 2 fuel oil. A long-term storage test revealed that there was no significant change in heat content and no visible stratification of SHO 20 blend during three months of storage. The pump pressure and the type of nozzle used affected the concentration of NOx, SO2, and CO in the flue gas. As was expected, increasing the SHO fraction in the blend also reduced the SO2 emission. The combustion of SHO 20 resulted in a higher flue gas temperature that increased the NOx emission than with No. 2 fuel oil.

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