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Biodiesel Fuel Quality Standard ASTM D6751 (B100)
Authored by Matt Quinn, Microbac Laboratories, Inc., Hauser Division
Biodiesel is being produced at increasing rates across the U.S. from primarily soy-bean oil, but also canola, peanut, sunflower, mustard and even algae. Biodiesel can be made from any source of mono, di or triglycerides, as well as pure fatty acids by first extraction of the oil followed by conversion.
The rate of biodiesel consumption in the U.S. has increased more than 10 times since the year 2001, Table 1.
Table 1.
U.S. Diesel and Biodiesel Consumption, 2000-2005
Millions of Gallons per year
| Diesel | Biodiesel | | 2000 | 37,238 | - | | 2001 | 38,155 | 9 | | 2002 | 38,881 | 11 | | 2003 | 40,856 | 18 | | 2004 | 42,773 | 28 | | 2005 | 43,180 | 91 |
Courtesy of the Department Of Energy: http://www.eia.doe.gov/oiaf/analysispaper/pdf/tbl13.pdf In 2008, a record amount 700 million gallons of biodiesel were reportedly produced in the U.S., (courtesy of biodiesel.org: http://www.biodiesel.org/pdf_files/fuelfactsheets/Energy_Use_Survey.pdf) Biodiesel is made by trans-esterifying the feedstock oil of choice by stirring or shaking with a precise amount of sodium methoxide. The resulting mixture is then comprised of two layers, a water soluble glycerin layer and an organic phase that consists of fatty acid methyl esters or FAMEs, also known as biodiesel.
In order to produce the highest grade of biodiesel, it is necessary to run the FAMEs that are separated from the glycerin through an extensive washing and cleanup phase. This cleanup phase consists of multiple water washes, chelation extractions and even dehydration procedures. If impurities like glycerin, methanol, residual salts, water, or even unconverted glycerides are left within the biodiesel, it can lead to serious mechanical damage within a vehicle. The damage can range from a simple clogged fuel filter to a burned-out fuel pump and even damaged fuel injectors. This is why it is necessary to test every batch of biodiesel produced against ASTM D6751 to ensure the highest grade of biodiesel. FAMEs can be used directly by diesel vehicles, however, they are typically blended with petroleum diesel which results in a B20 or 20% biodiesel mixture.
The biodiesel conversion process produces minor by-products, primarily glycerol or glycerin. It can be used as an additive after refinement for animal feed or can be sold for use in various food/industrial productions. This by-product also needs careful characterization to ensure it contains a low level of residual elements such as sulfur, sodium, potassium and even minimal methanol content.
The Hauser Division of Microbac Laboratories, Inc. is equipped to handle biodiesel testing in accordance with biodiesel quality standard ASTM D6751. The test protocol involves many individual ASTM tests such as:
* Water and Sediment D2709
* Water by Coulimetric Karl Fisher D6304
* Flash Point D93
* Methanol Content EN 14110
* Kinematic Viscosity D445
* Sulfated Ash D874
* Copper Strip Corrosion D130
* Cloud/Pour Point D2500
* Total Acid Number (TAN) D664
* Free/Total Glycerin D6584
* Oxidative Stability EN14112
* Cold Soak Filterability D6751 Annex 1
For more information on biodiesel, bioethanol or bioenergy analyses, please contact Matt Quinn in the Chemistry Department of Microbac Laboratories, Inc., Hauser Division with any further questions.
Matt Quinn
720.406.4661
mquinn@microbac.com
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For more information, contact:
Dr. Kim Baughman, Director of Development, Microbac Laboratories, Inc., kbaughman@microbac.com
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