The problem is not specific to location, either. Minnesota’s statewide clogging of diesel fuel filters last winter after its B2 mandate went into effect exemplifies the problem to a degree. What happened in Washington in the winter of 2004-’05, where similar fuel-related problems occurred in ferry boats fueled by B20 crossing Puget Sound, is a good case in point, too. A lesser-known case out of Utah appears to parallel Minnesota and Washington’s symptoms of troubled biodiesel. Frank Anderson of Cardwell Distributing says his company was buying B100 and blending it down to B20 for two months without incident. Once the cooler air hit in October 2005, the blender began to experience filter problems.
“We truck in our B100 from Colorado, and the samples off the trucks are crystal clear,” Anderson says. “We put the B100 in a heated, insulated tank. We send our truck to the rack and buy premium diesel with [an additive] package. We then blend 20 percent onto the truck and pump it into an above-ground tank.”
Anderson says samples are pulled from the truck after blending—before going into the above-ground tank—and everything still seems fine. After the fuel is pumped into Cardwell’s B20 tank, however, Anderson says, “For some reason, the fuel then separates, and there is a fallout of white slime that goes to the bottom of the tank and, in the process, out to our dispenser, [where it] clogs filters there and in our customers’ vehicles.” He says the bottom of the tank looks like it is covered with a foam that can best be described as “spray insulation.” Cardwell Distributing dealt with this issue from October 2005 well into 2006.
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Situations of this sort lead to more than just bad press for biodiesel. Individuals in the renewable fuel research community are passionate about biodiesel and its success, and fortunately, they strive to understand the nature of a pervasive problem in order to ultimately fix it.
Dr. Randall von Wedel, principal and director of research with CytoCulture International Inc., tells Biodiesel Magazine that he recently returned from Europe, where he had an informal meeting with top scientists in Berlin to discuss problems with near-ASTM-D-6751 biodiesel fuel in the United States. The information von Wedel obtained from that insightful meeting could explain why near-spec fuel (at or slightly above particular specifications in ASTM) would cause such seemingly aggravated problems.
A Meeting of the Biodiesel Minds
Von Wedel is a biodiesel veteran, who has been researching, testing and using biodiesel since the early 1990s. More recently, he developed a quick B100 field test, called the pHLip Test (see April 2006 Biodiesel Magazine). With his experience, even he doesn’t have all the answers behind recent quality problems. “I attended the conclusion of a board of directors meeting for the German Biodiesel Quality Control Board (GBQCB),” von Wedel says. “I visited with three scientists who work for the organization.” Among these three scientists was Dr. Jurgen Fischer, senior scientist with the ADM-Connemann Group. “[The GBQCB is] responsible—as we hope to be in the United States—for monitoring and enforcing quality control for biodiesel throughout the country,” von Wedel tells Biodiesel Magazine. According to von Wedel, the methodology of the German program includes rigorous sampling, sample collection protocols, sample archives and testing on a regular basis. Von Wedel says while some companies apply similar rigor in the United States, others don’t.
“It’s actually being done in California because we’re gun-shy out here,” says von Wedel, who lives and works in the Golden State. “We’ve had so many instances where we’ve received railcars [with] a certificate of analysis that says this railcar meets ASTM, but the reality is when we go to look at it, the fuel is turbid, it has precipitates, and if we collect samples off the bottom, it fails.” That’s what prompted von Wedel’s trip to Germany.
Decoding a Convoluted Spec
Precipitates have been settling out in biodiesel across the United States. Earlier this year, researchers discovered that some of those instances involved monoglycerides and diglycerides present in the fuel, indicating incomplete transesterification. Free glycerin is rarely a problem, either in the fuel or in meeting the spec. ASTM’s total glycerin spec of 0.24 percent is not so widely understood though, von Wedel says. “Total glycerin is an ASTM value that is a calculated value based on measurements,” he says. “It consists of four components.”
First, there’s the free glycerin that is supposed to settle in processing and be removed from the fuel. Simple water-washing accomplishes this. Second, if a producer achieves 96 percent to 97 percent transesterification, there are residuals that don’t completely esterify, von Wedel says. “They include, first, the triglyceride, which is really just the unreacted oil or fat,” he says, but those are rarely a problem either. “What comes up next are the residuals with the diglycerides, which is the same molecule (as the triglyceride) missing one fatty acid chain,” von Wedel says. “You don’t want that accumulating in your fuel or your engine.” The third one that becomes more problematic is the monoglycerides. Monoglycerides are a problem because they are more prevalent as a contaminant in biodiesel.
“Given X percentage of monoglycerides or Y percentage of monoglycerides, [lab techs] calculate how much of that is the actual glycerin portion,” he says, adding that 25 percent of monoglycerides and 12 percent of diglycerides make up the glycerin backbone included in the bound glycerin spec calculations, while the connected long fatty acid chains aren’t. “They do the same for the [diglycerides and the triglycerides], and the sum of those three individual numbers represents what is called ‘bound glycerin.’ They then take the bound glycerin and add it to the free glycerin, which should be very low, and they come up with a total number that’s called ‘total glycerin free and bound.’ That is why you can get 96 [percent] or 97 percent transesterification and still meet the ASTM total glycerin spec of only 0.24 percent. That’s the ASTM method. It’s awkward, and it’s a bit cumbersome. There’s nothing particularly wrong with it, but it’s deceiving.” He says the Germans confirm this test method is still the most reliable test protocol for bound and free glycerin despite its cost and complexity.
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