Blending vegetable oil with solvents

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Introduction to Blended Biofuels Diesel (BBD)

Blended Biofuels Diesel (BBD) is the process of making a fuel blend of oils with solvents. The purpose of making a biofuels blend diesel is to thin the resulting blended fuel to near the viscosity of diesel fuel, to improve the blend’s burn characteristics, and reduce its gel-point. The resulting solution should be a uniform solution without precipitates.

The common method of Blending Biofuels Diesel

The most common method of blending is to blend a petroleum distillate with a vegetable oil to thin it out to near the viscosity of diesel fuel. The most common petroleum distillates used in blending are gasoline (petrol), kerosene (paraffin) and/or diesel fuel.

Other commonly used solvents

Other solvents successfully used in making blended biofuels for diesel engines are: Acetone, Methyl Ethel Ketone (MEK), Pure Gum Turpentine (PGT), Xylene, Toluene, lacquer thinner, citrus oils, mineral spirits, paint thinner. Note: some of these solvents are not street-legal, so there might be heavy fines resulting in their use. They may also be hard on hoses and seals.

Theory behind Blending Biofuels Diesel

A solvent is used to reduce the viscosity of the source oil, because the viscosity of vegetable oils varies from plant oil to plant oil; however, the average is about 12 times as viscous as diesel fuel. Viscosity is also function of temperature, thus blend ratio is also a function of operating temperature.

Commonly used solvents in Blending Biofuels Diesel

Since the viscosity of diesel fuel is twice that of gasoline (petrol), then one needs to use twice as much diesel fuel as gasoline (petrol) for the same thinning effect. And, the viscosity of kerosene (paraffin) is halfway between that of diesel fuel and gasoline (petrol), so half again as much kerosene (paraffin) is needed as gasoline (petrol) to produce a functional vegetable oil-based road fuel for diesel engines.

There are other factors in choosing a solvent for blending. The most common other factor is the gel-point of the resulting solution. The gel-point of oils and solvents is the point at which a substance begins to solidify.

Gel-point of Blended Biofuels Diesel

Vegetable oils tend to gel at about 32F (0c). Diesel fuel gels at about -22F (-30c). Kerosene (paraffin) gels at about -60F (-51c). And, gasoline (petrol) gels at about -131F (-90c). However, a blend gels at a point between the gel points of its components, and is a function of the volumetric relationship between those components.

The typical functional blend ratios and useful temperature ranges

50% diesel fuel to vegetable oil will run fine in a heated fuel line up to 212F (100c) down to 28F (-2c). 30% kerosene (paraffin) to vegetable oil will run fine in a heated fuel line up to 212F (100c) and down to 15F (-10c). 20% gasoline (petrol) to vegetable oil will run fine in an un-heated fuel line up to 120F (50c) and down to 0F (-18c).

Blends of more than one solvent can be used

Some people prefer blending diesel fuel, vegetable oil and gasoline (petrol). Here are some functional relationships between the three components:

5% gasoline (petrol), to 40% diesel fuel, to 55% vegetable oil. 10% gasoline (petrol), to 30% diesel fuel, to 60% vegetable oil. 15% gasoline (petrol), to 20% diesel fuel, to 65% vegetable oil. 20% gasoline (petrol), to 10% diesel fuel, to 70% vegetable oil. 25% gasoline (petrol), to 0% diesel fuel, to 75% vegetable oil.

Blends with biodiesel

It is also common practice to blend solvents into biodiesel to prevent it from gelling at cold temperatures.

Diesel to Biodiesel blend ratios:

Gasoline (petrol), to Biodiesel blend ratios: 5% gasoline (petrol), to 95% biodiesel. 10% gasoline (petrol), to 90% biodiesel. 15% gasoline (petrol), to 85% biodiesel. 20% gasoline (petrol), to 80% biodiesel. 25% gasoline (petrol), to 75% biodiesel.

Jhananda 20:06, 9 April 2011 (UTC)