B100 biodiesel is a renewable fuel for diesel engines derived from biological fats, oils, and greases and meets the specifications of ASTM D 6751-06.

ASTM-D6751-06 Biodiesel Specifications for B100:

 

Property	ASTM Method	Limits	Units
Flash Point	D93	130 Min.	Degrees C
Water and Sediment	D2709	0.050 Max.	% Volume
Kinematic Viscosity, 40oC	D445	1.9 – 6.0	mm2/sec
Sulfated Ash	D874	0.020 Max.	% Mass
Sulfur	D5453
S 15		15 Max.	ppm
S 500		500 Max.	ppm
Copper Strip Corrosion	D130	No. 3 Max.
Cetane	D613	46 Min.
Cloud Point	D2500	Report	Degrees C
Carbon Residue 100% Sample	D4530	0.050 Max	% Mass
Acid Number	D664	0.50 Max	mg KOH/gm
Free Glycerin	D6584	0.020 Max	% Mass
Total Glycerin	D6584	0.240 Max	% Mass
Phosphorus Content	D4951	0.001 Max.	% Mass
Distillation Temperture Atmospheric Equivalent Temperture 90% Recovered	D1160	360 Max.	Degrees C
Sodium/Potassium	UOP391	5 Max. Combined	ppm

 

May 31, 2006

Flash Point – The flash point temperature is the minimum temperature at which the fuel will ignite (flash) on application of an ignition source under specified conditions. Flash point varies inversely with the fuel’s volatility. Flash point minimum temperatures are required for proper safety and handling of fuels. Note that the biodiesel component must meet a flash point criteria, prior to blending, for the purpose of assuring that the biodiesel component does not contain methanol. It is not possible, however, to rely on the flash point of the blend for the same purpose nasmuch as the flash point of the petroleum component is much lower.

Water and Sediment – Fuel should be clear in appearance and free of water and sediment. The presence of these materials generally indicates poor fuel handling practices. Water and sediment can shorten filter life or plug fuel filters, which can lead to engine fuel starvation. In addition, water can promote fuel corrosion and microbial growth. The level of water specified is within the solubility level of water in fuel and, as such, does not represent free water. Limits are established to allow measured results to be compared to a maximum level acceptable for proper ingine operation.

Physical Distillation – Distillation provides a measure of the temperature range over which a fuel volatizes or turns to a vapor. D1 typically has a greater volatility than D2; however, the inclusion of biodiesel at B20 blend levels results in comparable T90 temperature characteristics. Volatility directly affects the engine’s ability to operate as intended. Biodiesel does not have a traditional petroleum distillation characteristic; however, the addition of biodiesel to petroleum diesel in a blend can result in an increase in T90 distillation temperature. Higher volatility, as represented by a lower T90 temperature, generally provides better engine performance, while lower volatility generally provides better fuel economy. The T90 temperature specified has been evaluated for engine performance with biodiesel blends, up to B20, where the petroleum diesel fuel utilized in the blend met the requirements of ASTM D975.

Kinematic Viscosity – Kinematic viscosity affects injector lubrication and fuel atomization. Biodiesel fuel blends generally have improved lubricity; however, their higher viscosity levels tend to form larger droplets on injection which, can cause poor combustion and increased exhaust smoke. The limits established provide an acceptable level of fuel system performance for D1 and D2 fuel blends.

Ash – Ash is a measure of the amount of metals contained in the fuel. Ash forming materials may be present in three forms: (i) abrasive solids, (ii) soluble metallic soaps, and (iii) residual biodiesel catalyst. Abrasive solids and biodiesel catalyst materials result in wear of fuel system and internal engine components exposed to fuel after injection. Metallic soaps can contribute to deposits in the fuel system. All ash forming compounds can contribute to the accumulation of materials on diesel particulate filters, requiring filter maintenance. The levels specified are May 31, 2006 considered acceptable for engine performance; however, more stringent requirements may be necessary for optimal particulate filter maintenance intervals.

Sulfur – Sulfur levels in fuel are regulated by various governmental agencies to assure compatibility with emission standard requirements. In the United States there are currently three sulfur grades: S5000, S500, and S15, for both D1 and D2 petroleum diesel fuel. Biodiesel blends may not exceed the applicable maximum sulfur levels as defined for petroleum diesel.

Copper Strip Corrosion – The copper strip corrosion test indicates potential compatibility problems with fuel system components made of copper alloys such as brass and bronze. The limit specified is the same as that for petroleum diesel fuel.

Cetane Number – Cetane number is a measure of the fuel’s ignition and combustion quality characteristics. Biodiesel blend stock typically has a higher minimum cetane level than that of petroleum diesel. Fuels with low cetane numbers will cause hard starting, rough operation, noise and increased smoke opacity. The level specified is consistent with EMA’s requested increase in the minimum cetane number for petroleum diesel fuel.

Cloud Point – Cloud point is a test used to characterize the low temperature operability of diesel fuel. It defines the temperature at which a cloud or haze appears in the fuel under prescribed test conditions. The cloud point for biodiesel blends is generally higher than it is for petroleum diesel fuel. To avoid component precipitation in vehicle fuel tanks and blockage of fuel filters, the traditional blending practices for D1 and D2 for a given ambient temperature should be modified prior to blending with biodiesel. Alternative low temperature operability test methods such as Cold Filter Plugging Point (CFPP) and Low Temperature Flow Test may be agreed to between the supplier and the purchaser of the fuel.

Ramsbottom Carbon Residue – The Ramsbottom Carbon residue test is intended to provide some indication of the extent of carbon residue that results from the combustion of a fuel. The limit specified is the same as that for petroleum diesel fuel.

Lubricity – Lubricity is a measure of the fuel’s ability to provide adequate lubrication of the components of the fuel system, including fuel pumps and injectors. The precision required in the manufacturing of these components and the significant influence of abnormal wear require that they be adequately protected from scuffing, scratching, wearing, etc. that may affect their fuel delivery characteristics. The level specified is consistent with that recommended by suppliers of fuel injection equipment for modern diesel engines.

Acid Number – Acid number is a measure of acids in the fuel. These acids emanate from two sources: (i) acids utilized in the production of the biodiesel that are not completely removed in he production process; and (ii) degradation by oxidation. For biodiesel blends the acid number will change as a result of the normal oxidation process over time. Once purchased, biodiesel fuel blends that will not be utilized immediately should be monitored for changes in acid number as an indicator of fuel degradation. May 31, 2006

Phosphorus – Phosphorus has been shown to damage the ability of aftertreatment systems to reduce exhaust emissions as intended. The influence of phosphorus is cumulative; therefore, very low levels of contamination over the significant amount of fuel consumed by an engine may lead to unexpected deterioration of the aftertreatment system.

Total Glycerin – Glycerin is a byproduct of the production of biodiesel. If glycerin remains in the finished biodiesel, or biodiesel fuel blend, it can result in fuel separation, material incompatibility, engine deposits and engine durability concerns. In finished fuel blends, the ability to directly measure glycerin is compromised by interference with naturally occurring petroleum diesel fuel components. When an acceptable test method for Glycerin in a fuel blend is available, a limit value will be established.

Alkali Metals – Sodium and potassium are "alkali metals" utilized as catalysts in the production of biodiesel and should be removed through the biodiesel production process. Residual Alkali metals can form deposits in fuel injection system components and poison emission control aftertreatment systems.

Alkaline Metals – Magnesium and calcium are "alkaline metals" utilized as absorbents in the production of biodiesel and should be removed through the biodiesel production process. Residual Alkaline metals can form deposits in fuel injection system components and poison emission control aftertreatment systems.

Blend Fraction – It is important that the amount of biodiesel utilized in a given fuel blend be identified and uniform throughout the blend.

From the time of production, biodiesel fuels are unstable due to the natural oxidation process. The process involves a free radical chain reaction that continues until the reactive molecular links or available oxygen are depleted. Peroxides (hydroperoxides) are reactive oxidizing agents formed during the first steps of fuel oxidation. At high concentration, peroxides or the free radicals formed can damage or degrade certain plastics and elastomers, particularly at higher temperatures. Subsequent steps in the oxidation process produce acids, gums, polymers, and other insoluables.

Thermo-oxidative Stability, Insolubles – Polymers and other insoluble materials that are formed during oxidation result in fuel filter blockage. Fuel that meets the specified limit at the time of retail sale is expected to provide six months of storage capability, depending on storage conditions, before degradation occurs. Fuel should be monitored to determine if degradation has taken place and necessary steps taken to avoid the use of degraded fuel. It is important to note that the test method utilized must be modified to use glass fiber filters to prevent degradation of the filter media by the biodiesel.

Oxidation Stability, Induction time – Historically, petroleum diesel fuels have exhibited extremely long storage stability periods. In some cases, the processing required to produce very low sulfur level petroleum diesel fuels has significantly reduced the stability of the petroleum fuel component in biodiesel blends. The test method utilized predicts the amount of time that fuel can be stored before the production of acids indicates that the fuel is becoming unstable. Fuel that meets the specified limit at the time of retail sale is expected to provide six months of storage capability, depending on the storage conditions, before degradation occurs. Fuel should be monitored to determine if degradation has taken place and necessary steps taken to avoid the use of degraded fuel.