July 25, 2012
BY The National Biodiesel Board
Fuel quality and a strong set of standards remain one of the highest priorities for the biodiesel industry. That is why the industry continues to refine the ASTM biodiesel specifications to meet the needs of customers with ultra-low sulfur diesel (ULSD) and new diesel engine and aftertreatment technology. A new voluntary No. 1-B grade for biodiesel (B100) passed the ASTM D2 Committee on Petroleum Products and Lubricants this past spring and the results were sanctioned by the ASTM Committee on Standards in a meeting held late last week.
“The biodiesel industry took a proactive stance to improve the standards governing America's advanced biofuel,” said Joe Jobe, CEO of the National Biodiesel Board. “For the large majority of biodiesel users, the current standard along with conventional industry management practices allow for biodiesel blend use year-round, even in extreme climates.” ASTM D6751, the ASTM standard for B100 prior to blending, was modified to create a new voluntary No. 1-B grade. The new grade provides more stringent controls for minor components in raw materials used to make biodiesel, such as vegetable oils and animal fats. The specification values of the current standard will become the No. 2-B grade in D6751 without change. Producers or blenders can continue to utilize the current specification under the No. 2-B grade at any time of the year exactly as done today, or they may opt to use the more stringent No 1-B grade. The finished blended fuel standards—D975 for on- and off-road diesel up to 5 percent biodiesel (B5), D7467 for B6 to B20 on- and off-road applications, and D396 for heating oil up to 5 percent biodiesel—do not change. B100 used for D975, D7467, and D396 must continue to meet D6751 (either the No. 1-B or the No. 2-B grade) prior to blending.
The choice of the No. 1-B and No. 2-B designations were selected to make the standard as similar as possible as the current mode of operation with No. 1 and No. 2 diesel fuel. Most users utilize No. 2 diesel fuel, but if they experience unexpected filter clogging they can switch to No. 1 diesel fuel, use additives or other means to prevent unexpected filter clogging. The same philosophy is to be maintained with the No. 1-B and No. 2-B biodiesel specification, i.e., most users will continue to utilize the No. 2-B biodiesel but if unexpected filter clogging is experienced, No. 1-B can be used for blending.
The interest in creating No.1-B specification was triggered by a handful of cases with the new ULSD fuel experiencing unexpected filter clogging above the cloud point of the finished blend, which mostly occurred with low aromatic No. 1-type diesel blends. The voluntary No. 1-B grade maintains the same parameters as the current standard, and provides more stringent controls for minor components, which have been implicated in rare filter clogging in the field with ULSD. Monoglycerides were chosen as a surrogate for all minor components and are limited in the new No. 1-B grade to 0.40 percent mass maximum, and the Cold Soak Filtration Time is limited to 200 seconds year around.
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“We are committed as an industry to being proactive so that the end user gets the best product possible,” said Kyle Anderson, technical projects manager for the NBB. “As part of our ongoing commitment to improving the standards and fuel quality, we will continue to investigate these rare phenomena and may propose further changes over time as more data and improved test methods become available. Biodiesel is one of the most tested fuels in the world, and that’s why customers can have confidence in biodiesel blends with ULSD and new diesel engines and after treatment technology moving forward.”
The No. 1-B specification passed the ASTM D2 Main Committee on Petroleum Products and Lubricants via electronic ballot adjudication of negatives from the December 2011 ASTM D2 meeting. The handling of the negatives was reviewed and approved by the ASTM Committee on Standards at a meeting late last week. The modified version of ASTM D6751 containing the new No. 1-B grade will be released for public use later this summer after editorial review and typesetting.
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