Biodiesel's Quality Evolution

How the industry has overcome one of its most daunting challenges
By Ron Kotrba | August 26, 2013

Discussing major improvements in biodiesel fuel quality is impossible without delving into the rich history of this young industry. Biodiesel emerged on the U.S. alternative fuels radar in the early 1990s, and for the next decade it slowly gained recognition as a real-world, here-and-now replacement for diesel fuel before its first ASTM specification, D6751, was published in 2001-‘02. Since then, the tale of U.S. biodiesel is a series of highs and lows. Early public policy support primed the pump for years of major industrial expansion, but with fast growth came damaging reports of product quality issues in the field. Meanwhile, skyrocketing feedstock prices, the global financial crisis and intermittent, prolonged lapses in federal tax support, not to mention RIN fraud and other serious issues, stalled industry growth. Fortunately, the industry has proven resilient enough, under resolute organizational leadership, to bounce back and experience its greatest year yet. From a fuel quality perspective, kick-starting 2013 with positive results from National Renewable Energy Laboratory’s latest quality survey certainly didn’t hurt matters.

As NREL senior fuels chemist Teresa Alleman took the stage at the 2013 National Biodiesel Conference & Expo in Las Vegas to discuss preliminary results from the survey, which showed 97 percent of the 67 samples tested (53 producers and 14 terminals)—representing 94 percent of volume in the market—were on-spec, she acknowledged, “This is a huge improvement over previous years.” Months later, NREL issued a press release that stated 95 percent of the samples were on-spec. “The small discrepancy was an error on our part between the meeting and the final report,” she tells Biodiesel Magazine. “I have gone back and checked the information, and 95 percent is correct.” Nevertheless, the results were huge improvements over previous years.

In 2004, NREL’s first survey showed 85 percent on-spec fuel, when D6751 was far less stringent than today’s standard. In her final report, Alleman notes that since 2002, D6751 has undergone 17 updates to help prevent or reconcile issues found in the field, or to stay ahead of changing technology and customer demands. The next survey was in 2006, during the height of the industry expansion boom, and results were dire. Only 41 percent of biodiesel samples were on-spec, meaning more than half failed, mostly for total glycerin or flash point. At the behest of the National Biodiesel Board, NREL did things a little differently for the 2008 survey. It was volume-weighted, meaning producers were binned based on actual production volumes. The 2007 biodiesel market was estimated at 394 million gallons at the time of the survey when samples were pulled. Samples were collected from 52 percent of the existing U.S. producers representing nearly 70 percent (287 million gallons) of all U.S. production. Large producers met specs nearly 95 percent of the time. Small- and medium-scale producers had more trouble meeting the specifications, particularly oxidation stability. Even so, the volume-weighted failure for oxidation stability was less than 10 million gallons. Other failures were weighted at less than 2 million gallons.

For the most recent survey, the critical properties tested were free and total glycerin, flash point, cloud point, oxidation stability, cold soak filterability and metals. In her report conclusions, Alleman notes, “The samples collected in this study were typically high quality and met the D6751 specification limits, with a few notable exceptions. In particular, one sample failed multiple properties and was clearly an outlier compared to other samples in this survey. The failure rates on [the cold soak filtration test] and oxidation stability were less than 5 percent, with one failure on flash point and no failures on the other critical properties tested.”

Alleman tells Biodiesel Magazine that she believes the industry takes quality seriously, a belief evidenced by the latest survey results. “The industry knows it cannot continue to grow and expand without producing a quality product, and it has stepped up to meet that challenge,” she says. “The biodiesel industry makes quality a priority and needs to ensure producing a quality product is a core value—there is no excuse for producing poor-quality biodiesel. This may be especially true as new feedstocks reach the marketplace. The U.S. biodiesel industry is feedstock neutral so, as an industry, we need to be aware of what changes are needed in specifications and test methods to ensure quality now and into the future. That means staying abreast of changes in ASTM specifications and properties, federal and state quality requirements, and continuing to be vocal and active in supporting biodiesel.” 

Clearly no one, single event caused this vast improvement in fuel quality; a philosopher may contend this is a dialectical necessity when considering the material conditions this industry’s history has brought into existence. A recurring fuel problem in the field, such as filter plugging, gains the attention of industry leaders and fuel purchasers. Investigations begin and action is initiated at ASTM where voting, adjudication and precision take place. Ultimately a measure such as the CSFT is implemented, thereby helping reduce issues in the field. Diesel technology advances such as aftertreatment equipment to reduce particulate matter and NOx emissions have sensitive precious metal catalysts that can foul in the presence of too much sodium, potassium or magnesium from residual catalyst or dry-wash filtration media left in the final product. OEMs push for limits in D6751 before approving biodiesel blends. Action ensues at ASTM to put a cap on these metals so engine makers can remain confident that biodiesel blends that customers run in their engines won’t foul catalysts and cost untold millions in warranty payouts. Years after the $1 per gallon blenders tax credit went into effect, the IRS began requiring producers claiming the tax credit to meet ASTM specs. In addition, the renewable fuel standard requires registration with U.S. EPA and, to generate RINs, qualifying fuel must meet ASTM specs. All of these scenarios, and more, have contributed to recent U.S. biodiesel quality improvements, which are directed by every conceivable angle: from the top (industry leadership and government) down, the bottom (users) up and sideways (fuel purchasers, OEMs).

The men at the center of ASTM biodiesel activities are Steve Howell, longtime NBB technical director who was recently promoted to a senior technical advisory role with NBB, and Scott Fenwick, the organization’s new technical director. “While the biodiesel of 10 years ago was a good fuel and caused relatively few issues, the biodiesel being produced today is far superior and reported issues from the field are now on par—perhaps even less—than those reported for conventional petroleum-based diesel fuel,”  Howell tells Biodiesel Magazine.

Howell says the dramatic improvement in fuel quality is mainly attributed to three factors. “First and foremost, the industry has now largely embraced the BQ-9000 fuel quality program of the National Biodiesel Board,” he says. “To qualify for the BQ-9000 quality program, companies must agree to meet the ASTM D6751 specification and have a fully implemented quality management system, be subjected to independent third-party audits, and agree to physically analyze every lot of biodiesel produced for the most critical parameters in the specification.” He says in 2012, more than 85 percent of the biodiesel produced—approximately 900 million gallons—was done so by BQ-9000 producers. 

“The second factor has been the efforts of the NBB to encourage regulators to assist the industry by enforcing D6751,” Howell says. “As a trade association, the NBB can encourage the use of the specifications, but it does not have the legal authority to enforce them or shut down a biodiesel operation if it is not producing to ASTM standards. That authority lies within the EPA as part of its legal authority to register and regulate fuels in the U.S., within the IRS, which manages taxing and incentives for biodiesel, and by the individual state regulators who have authority over consumer fuel pumps and fuel quality.” He says NBB members have unanimously voted to direct staff and contractors to actively encourage each of these regulatory agencies to fully adopt and enforce the biodiesel standards. “Over the past several years, NBB has actively worked with EPA, the IRS, and the state [weights and measures] representatives to secure D6751 as a requirement for various EPA and IRS programs, such as RFS2 and the federal biodiesel tax incentive, and as the legal standard for biodiesel in every state except Alaska and New Jersey.” He adds that NBB is currently working on legislation in New Jersey that will adopt D6751, but the organization has no plans to work further in Alaska. “There aren’t very many trade associations that have directed its staff to work with regulators to regulate them more,” Howell says, “but that is how serious the biodiesel producers are about quality and meeting the ASTM standards.”

The third factor spurring quality improvements in U.S. biodiesel, according to Howell, is the overall growth of the market and sophistication of the blenders and marketers who are buying B100. “With the advent of more than 1 billion gallons of biodiesel sold in both 2011 and 2012 under RFS2, many major petroleum refiners are now buying biodiesel and selling biodiesel blends under their own brand name,” he says. “These large, risk-averse companies are now major buyers of B100. They are putting BQ-9000 as a requirement in their bid specs and monitoring their fuel quality on an ongoing basis to help insure their customers will have a positive experience with the biodiesel blends they sell.”

It’s not just BQ-9000 that the oil companies and biodiesel blenders demand. Despite the nearly 20 updates to D6751 over the past 12 years, many customers have their own specs biodiesel must meet—specs that go beyond what’s required in ASTM. One source, a biodiesel producer, says ASTM specifications do not go nearly far enough to ensure quality biodiesel, which is why these purchaser specs have become more common in the past few years.

“ASTM fuel specifications are designed to be the minimum performance requirements necessary for the fuel to perform in their intended application for the consumer,” Fenwick says. “Within the fuel distribution system here in the U.S., there are several potential additional parties that may come in contact with the fuel before the consumer purchases it at the pump. Each change of hands between the fuel buyers, blender and distributor is a potential opportunity for the degradation of that fuel. As each of these parties becomes more educated with biodiesel and its properties, their ability to handle the fuel improves.”

Fenwick acknowledges the biodiesel industry has become more sophisticated over the years. “I believe that the biodiesel producers today have a better understanding not only of their own processes, but how the fuels industry operates,” he says. “Most have had a few years of continuous operation to improve upon their technical and business skills.” This is an important point because the biodiesel industry’s roots are in agriculture, not fuels and chemicals, and after all, a biodiesel facility is a chemical plant that requires the knowledge and discipline of chemical manufacturing. “There have been some biodiesel producers that might have been quick to jump into the market due to the influx of capital investments years ago,” Fenwick says. “Some of these producers didn’t understand, or haven’t been able to navigate, the fuels market. The biodiesel industry hasn’t become their ‘Field of Dreams’ that they had hoped when they thought that ‘if you build it, they will come.’ A number of the plants have since become acquired by larger, growing companies that are willing to make the investment in the future of biodiesel.”

Fenwick adds, “I also believe that the NBB, along with the customers of these producers, have been better able to communicate and explain the rationales behind the required testing and limits. The limits within the ASTM specification have been carefully vetted to determine the minimum requirements for biodiesel to be properly blended and used within the transportation fuel market. Blenders and fuel distributors have since put into place typically tighter purchase specifications to help ensure that they are able to deliver that fuel to the end consumer.”

The ASTM Biodiesel Task Force’s work never ends though, as it continues to work with the biodiesel, petroleum and OEM stakeholders at ASTM on several fronts. As diesel engines—and petroleum fuels—change, the group is constantly monitoring whether changes are also needed for biodiesel. “Ongoing industry-sponsored testing programs are in progress to confirm the current specifications for metals are protective of the new exhaust system catalysts and on-board diagnostics sensors now being implemented on diesel engines, and to provide more advice on the long-term storage of biodiesel blends and cold flow properties when blended with ULSD,” Howell says. The task force is also monitoring activities and issues identified with ULSD fuel containing no biodiesel—some internal injector coking and filling station tank corrosion—as well as efforts by the Truck and Engine Manufacturers Association (EMA) to modify the specifications for finished diesel fuels regarding water and sediment values. “EMA has proposed to change from the current D975 and D7467 specification on combined water and sediment—500 ppm maximum using the D2709 centrifuge method—to three separate measurements: 200 ppm maximum Karl Fischer moisture, 24 mg/kg maximum filterable particulates, and a 2 maximum visual haze rating,” Howell explains. “Longer term, EMA and the fuel injection equipment manufacturers are interested in moving the diesel fuel particulates to even more stringent values, which measure total number of particles of various micron sizes or bins—more similar to the particulate specs of hydraulic fluids. Some of this activity for diesel fuel in general is being driven by a desire to increase overall diesel fuel quality as new, clean, quiet and powerful diesel passenger cars are being introduced into the U.S. market to meet ever-increasing fuel economy standards. These new diesel passenger cars are getting mileage comparable to gasoline-electric hybrids, are less expensive and are as clean as, or cleaner than, natural gas vehicles, and are projected to see significant increases in sales. The biodiesel industry is working cooperatively with engine and vehicle manufactures to make sure biodiesel blends will work as well as—if not better than—conventional petrodiesel in these new diesel passenger cars.”

As with any product, even with other fuels, consumers expect that the products they purchase will work for their intended application, Fenwick says. “The industry understands that its future growth and prosperity depends upon the quality and performance of the product they produce today.”

Author: Ron Kotrba
Editor, Biodiesel Magazine
[email protected]

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