Biodiesel

What are the issues?

Biodiesel is referred to as a diesel equivalent. It has been used in various forms as a fuel for diesel engines from the very beginning. The first engine designed and built by Rudolph Diesel was run on peanut oil.

Biodiesel is defined as alkyl esters made from the transesterification of vegetable oils or animal fats. Transesterification refers to the process used to remove the Glycerin from the base plant or animal oils.

Properly transesterified, dried, and filtered biodiesel can with some moderate changes be successfully used to fuel diesel engines and as burner fuel.

Biodiesel however is not diesel fuel; it is chemically very different from petroleum derived fuels. These differences require the user to educate themselves and to make certain changes in order to successfully use it.

• Biodiesel is an organic based product; it will deteriorate much more quickly than petroleum based fuels.

• It oxidizes much more quickly than petroleum diesel

• It has storage problems. It can significantly break down chemically in as little as 60 days

• It has far less thermal stability than petroleum diesel

• It holds up to 10 times as much dissolved water as petroleum diesel

• It is a powerful solvent that will delaminate rubber hoses, deteriorate seals and gaskets, and damage many types of sensors. This high solvency will also break down fuel system deposits.

• Biodiesel has significant cold weather problems.

• If you plan using a blend with more than 5% biodiesel check with your engine manufacturer?s representative regarding possible maintenance and warranty issues.

Explanation

As fuel oxidizes, it deteriorates and darkens. It will more easily form gums, varnishes, and carbon deposits; it can make the vehicle harder to start, and reduces power output.

Biodiesel begins to very quickly break down. Over a period of time it will separate into lesser components becoming unstable, and finally unusable. It will also grow bacteria and fungi at dramatically increased rate over regular diesel.

Thermal stability is a problem with biodiesel; it can be a problem with fuels used in diesel engines, as the fuel is recirculated through the engine the constant high heat will deteriorate far more quickly than petroleum diesel. Storage at any temperature over 85?F can accelerate this process.

Dissolved water is a problem on several fronts, first it is corrosive and can quickly damage unprotected metal parts, it is the prime culprit in the growth of bacteria and fungi in fuels, and as the fuels temperature is lowered the high level of dissolved water is forced out of the fuel and can become ice crystals which can cause filter problems.

B100 has been used as chemical solvent in industrial processes for many years. It is very strong and can soften and delaminate hoses, seals, and gaskets. It can even attack non-rubber components. Blending with petroleum diesel will ameliorate this to some extent, however it is very important to check all of these components on a regular basis even when using as little as 2% biodiesel (B2). This solvency can break down deposits so quickly it can cause rapid filter plugging.

Biodiesel has severe cold weather problems, it can cloud at 50?F, gel at 20?F-40?F, and become solid at 10?F-30?F. The more highly saturated the base oil used to derive biodiesel the higher the gel point and the more difficult it is to treat. Biodiesel?s cold flow properties are not improved by standard petroleum diesel fuel anti-gel products. Biodiesel requires a completely different technology to operate successfully in cold weather.

Blending biodiesel with petroleum diesel can help reduce many of the problems mentioned above. Biodiesel blends are denoted as ?B? numbers, for example B100 is pure biodiesel, B2 is 2% biodiesel and 98% petroleum diesel, B5 is 5% biodiesel and 95% petroleum diesel, and so on.

To successfully blend biodiesel and petroleum diesel you must have a biodiesel that has been properly transesterified, dried and filtered to meet ASTM D 6751 or EN 14214. The biodiesel and petroleum diesel need to be above 40?F when blended, and you need to have active agitation to ensure complete blending.

Improperly blended biodiesel blends will separate and cause significant problems during cold weather. Cold Flow Improvers (antigels) designed for B100 biodiesel such as EnerFlow 1000 can be added prior to blending with the petroleum diesel or you can use a dual technology product such as EnerFlow 20 to treat the blended biodiesel.

Many OEM engine manufacturers limit users to no more than 5% (B5) biodiesel. Use of biofuel with more than 5% biodiesel can negatively affect some warranties.

What do I need to do to safely and effectively use Biodiesel fuel blends?

1. Make sure your fuel supplier certifies that your biodiesel meets ASTM D 6751 and or EN 14214.

2. Ask your fuel supplier what the CFPP of the B100 fuel was before blending. It should be 15?F or lower.

3. Ask your fuel supplier how the biodiesel and petroleum diesel is blended. (see above)

4. Ask your fuel supplier what the CFPP of the blended fuel is as delivered. Depending on your location, it should be 0?F to -20?F.

5. Make sure your fuel storage tank is clean and water free before unloading biodiesel.

6. Use a product such as EnerFlow 20 to disperse water, improve cold flow characteristics of both the biodiesel and petro diesel parts of the blend, raise Cetane, clean injectors, inhibit corrosion, improve lubricity, slow oxidation, and stabilize the fuel. In some special cases a product such as EnerFuel can be used.

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Last modified: 01/12/09