Proof of Quality: A New Biodiesel Fuel Quality Report by National Renewable Energy Laboratory

by Ron Kotrba (Biodiesel Magazine) A new biodiesel fuel quality report by National Renewable Energy Laboratory surveying U.S. and Canadian BQ-9000 producers suggests the North American biodiesel industry has learned the lessons of its past. -- U.S. biodiesel fuel quality has been on an ever-increasing trajectory upward since the darkest days of its past in 2006, when a B100 quality survey performed by National Renewable Energy Laboratory showed nearly 60 percent of samples failed specification. Not only has fuel quality improved dramatically since then, but the stringency of ASTM D6751 has also increased significantly.

Teresa Alleman, a senior fuel chemist with NREL, made her first appearance in several years on stage at the National Biodiesel Conference & Expo in Tampa this January to discuss the biodiesel industry’s latest fuel quality report—an expansive compilation of B100 test data from BQ-9000-accredited producers.

BQ-9000 is the U.S. biodiesel industry’s quality assurance program and, according to Scott Fenwick, technical director for the National Biodiesel Board, more than 50 producers in the U.S. and Canada are BQ-9000-certified. “Those producers in the program represent approximately 93 percent of the gallons that are represented by the NBB,” Fenwick said.

Diesel fuel quality is becoming increasingly important as engine technologies rapidly advance to keep up with tougher emissions and fuel economy regulations. “Engine technologies are changing faster and faster, with tighter and tighter tolerances,” Fenwick said. “Fuels need to be cleaner and cleaner. We half-jokingly say that, in the very near future, your fuel will be cleaner than the drinking water that you’ve got in front of you. Understanding where we are [with respect to biodiesel fuel quality] gives OEMs a baseline on where they can begin to adjust their engines for future designs and provide information back to regulators on where we stand.”

What prompted this latest fuel quality assessment, according to Richard Nelson of Enersol Resources, was a fuel quality study conducted in 2017 by Germany’s biodiesel quality management association AGQM, the results of which were released in 2018. The AGQM investigation collected 53 samples from 15 producers and analyzed 1,060 parameters, concentrating on metals. The results were very positive. All samples met or exceeded the DIN EN 14214 biodiesel standard and even stricter AGQM requirements. Only 14 limits were violated, but all violations were within the precision of the method. Since then, AGQM has performed two subsequent surveys, the latest of which involved three sampling campaigns in 2019. The 2019 results, just released this spring, showed significant improvement over 2018. In 59 samples taken, which resulted in 1,062 analysis data, only seven limit violations could be determined.

Nelson said tractor engine manufacturer Deutz wanted to know what the state of biodiesel fuel quality was in order to warranty biodiesel in engines.

Metals content is perhaps one of the most important parameters for OEMs, considering future aftertreatment designs may use close-coupled SCR systems whose catalysts are highly sensitive to metals contamination. Unlike today’s systems that feature a diesel oxidation catalyst followed by a diesel particulate filter and then an SCR catalyst, more stringent NOx reductions may require future aftertreatment designs to expose sensitive SCR catalysts directly to exhaust manifolds at high temperatures and putting the catalysts directly in the line of fire of any metals exiting the combustion chamber.

Conclusion
“So, we really have collected a huge amount of data to see where the U.S. and Canadian biodiesel industry is,” Alleman said. “The [metals data are] easily orders of magnitude under the spec limit. We are so far below these limits on the metals—that’s a very important story. I hope my OEM friends in the audience are taking good notes.”

“This data is a snapshot in time, at the point of production,” Fenwick said. “Quality does not get better as it goes along. There is a myriad of ways in the distribution system to [pick up contaminants].”

One might argue that, given all the data used was from BQ-9000 producers, this analysis tested the best of the best, which is true. Not all biodiesel in the U.S. market is produced by NBB member-producers, and not all NBB member-producers are BQ-9000-certified. However, NBB member-producers and BQ-9000-certified producers represent a vast majority of the biodiesel fuel sold in the U.S. market.

“Never before has NREL been able to provide this level of fuel quality information,” Alleman said. “By partnering with NBB’s National Biodiesel Accreditation Commission, BQ-9000, we now have a simpler, more efficient way to collect, analyze and determine the quality of biodiesel. These reports will act as a reoccurring insight into biodiesel fuel quality each year.” As Alleman indicated, this will be a yearly assessment moving forward.

“These reports show what we’ve been saying for years,” Fenwick said. “Biodiesel fuel is of the absolute highest quality, and these reports prove it. Having this data every year will go a long way in demonstrating to OEMs and regulatory agencies that biodiesel should be the fuel of choice for any diesel engine.” READ MORE