The Tangled Web: Pipelines, Jets and Biodiesel

To some skeptics, the preclusion of biodiesel in the pipeline network was by and large predetermined before the industry manufactured enough gallons to even worry about it. With merit some assert it's the aviation customers higher on the food chain who really run the show, because of the care and cost that are put into jet propellant. The assertion is that those customers hinder biodiesel's acceptance in the pipeline, telling suppliers that they will not buy their fuel if methyl ester contamination is possible to any degree.

Then there are those who say that the problem lies with jet engine manufacturers, who haven't researched this enough to set a maximum trace allowance for jet fuel as it relates to airplane engine performance and safety. On that note, the absence of a single-digit parts per million (ppm) test method and instrumentation makes the lack of a max trace threshold moot. Unfortunately concerns about biodiesel properties and the quality of the larger intermingled pipelined diesel fuel pool continue to hold back its wider acceptance in the pipelines. A Spanish company however, is pipelining a bioblend without incident via the same infrastructure through which jet fuel is transported. Because of the international nature of jet fuel specifications-planes flying from the United States to Spain must refuel-the entire argument against pipelining biodiesel needs to be revisited.

Setting a Precedent: Conspiracy Theory or Reality?
The replacement of No. 2 low sulfur diesel (LSD) fuel, which contains 500 ppm of sulfur, with 15-ppm ultra-low sulfur diesel (ULSD), as part of U.S. EPA's diesel emissions reduction plan, opened up a can of worms that some say still affects the biodiesel industry today. For years, sulfur acted as a lubricity agent in diesel fuel until it was significantly reduced to comply with new advanced emissions control devices debuting commercially in the 2007 model year. Lubricity additives of a different nature would come into play, and with them new concerns about how those additives, if blended at the refinery, would affect other products moving in the same pipeline.

In October 2004, Colonial Pipeline Co., the largest pipeline network in the Eastern United States, decided not to allow lubricity additives in its network. When Colonial Pipeline decided to exclude ULSD treated with lubricity additives from its network, most other pipeline operators followed suit according to the American Petroleum Institute's Al Mannato, who presented in November 2004 at a ULSD workshop. The reason: residual amounts of lubricants were detected in products such as jet fuel in which these additives are prohibited.

Prior to Colonial Pipeline's October decision it announced procedures for the approval of additized ULSD, two of which stated the additive must not impact the quality of other products; and there be an upper limit placed on additive concentration. Subsequent testing by the pipeline operator yielded microseparometer values indicating degradation of jet fuel. Jet fuel thermal oxidation tester results conducted by Colonial Pipeline also indicated a kerosene movement was degraded and trailback of the lubricity additive was detected in the kerosene. These poor results led Colonial Pipeline to exclude lubricity additives in its line. According to an article published in the trade journal Pipeline & Gas Journal in November 2004, the pipeline spent five months testing and moved three trial shipments with additized ULSD before reaching its decision; however, the journal notes, results from these tests don't mesh with Colonial Pipeline's earlier laboratory tests or with experience from pipeline operators outside the United States. So what does any of this have to do with
biodiesel?

A biodiesel trader working in the fuels distribution field who requested anonymity tells Biodiesel Magazine that after Colonial Pipeline made its decision to exclude additized ULSD in its line, truck racks across the nation were required to make large $1 million plus investments per site in order to blend lubricity additives at the terminals rather than at the refineries. "That lubricity additive is basically a methyl ester," the source says. "After doing all of that, they could hardly turn around a month or two later and say, 'Oh yeah, we excluded the lubricity additive but you can move a B5 blend.' So the timing for biodiesel pipeline acceptance and the ULSD rollout was very much a problem. It's been something for the pipeline guys to hide behind in order to put this thing off."

Jet Fuel and Engines
Many media reports regarding airlines and jet engine makers testing or using biofuels have come across the wire in the past several months but none of these include methyl ester biodiesel. If jet fuel traders express such concerns over ultra-low concentrations of fatty acid methyl ester (FAME) trailback in aviation fuel, then using a biodiesel blend in jet engines is certainly out of the question. Representatives from Buckeye Partners and Northville Products Services, who presented at the 2008 National Biodiesel Conference & Expo, indicated that jet engine makers need to determine a maximum trace FAME allowance in jet fuel in order to give would-be biodiesel movers a threshold within which trailback could be contained. Conversely, a low-level FAME detector, which reads down to single digit ppm, has yet to be developed.

In February 2007, NPS released its report on B5 test movements through Colonial Pipeline in which the bioblend was followed by LSD. In its report, the company states, "The sampling of the trailing low sulfur diesel batch identified some level of trailback. The exact quantification of the trail- back is impossible to determine due to the current inaccuracy of the test methods at very low levels of methyl esters. … [Colonial Pipeline] has determined that methyl ester trailback will require segregation of jet fuel shipments to prevent any amounts of contamination … The adverse affects of this 'batch approach' is that it adds costs to the system at multiple points and minimizes shipper and pipeline operating flexibility."

NPS notes in the report's conclusion that test methods to determine trailback below 1.7 percent by volume do not readily exist commercially, adding, "NPS and [Colonial Pipeline] would like to see a test method developed with accuracy to single digit parts per million of methyl ester." According to information presented one year later at the 2008 National Biodiesel Conference and analytical companies' reluctance to comment on the issue, this is still the case ostensibly. Matt Bowman, global technical sales development manager for PerkinElmer LAS, says, "There is at least one technique PerkinElmer has that can detect bio-material." Bowman says the technique is not specific to biodiesel (FAME) or ethanol, but it could be used to determine cross contamination in pipeline products. "As with most problems, necessity is the mother of invention," he says, implying there is little need as of yet for trace FAME test methods and instrumentation.

Biodiesel Magazine attempted to get comments from jet engine makers on the lack of a fuel specification established to cap trace methyl ester content in aviation fuel, but they were reluctant to comment. Only one engine maker chose to respond to requests for information. Boeing said it would prepare a statement for this article on the matter. Instead, Peter Conte of media relations with Boeing Commercial Airplanes sent an e-mail stating, "We are going to decline to comment on this matter at this time. I would encourage you to contact us again in the not-too-distant future after we have made more progress with our biofuel research."

Compania Logistica de Hidrocarburos, a Spanish fuel logistics company, has been moving B5 in its pipelines for one year, according to Pedro Martinez, CLH director of communications. "At the moment, we protect aviation kerosene batches with other petroleum products without biodiesel in order to keep the content of methyl ester in jet fuel below 5 ppm," Martinez tells Biodiesel Magazine. The protocol for this he says can be found in Joint Inspection Group bulletin #15. "This is not the best solution, so we hope new jet fuel specifications will allow a certain content of biodiesel-like 100 ppm-to get a sustainable solution."


Ron Kotrba is a Biodiesel Magazine senior writer. Reach him at [email protected] or (701) 738-4962.