Terminal Error

Blending mishap sends incorrect blends to Minnesota stations
By Kris Bevill | November 15, 2011

In October, a technical malfunction at a Magellan Midstream Partners LP terminal in Mankato, Minn., caused high percentages of ethanol to be blended with gasoline at the terminal. The unapproved fuel was then distributed in 108 truck loads to more than 60 retail gas stations and cooperatives over a four-hour period on Oct. 8, according to information the company provided to state officials Oct. 10. Magellan immediately shut down its terminal to prevent more high-blend ethanol from being distributed and cooperated with state officials to recover the fuel that had already left the terminal. The process was time-consuming, in part, because some of the off-spec gasoline was delivered to bulk plants and secondary distributors. On Oct. 17, Magellan announced it had resumed gasoline loading operations at the terminal. “Virtually all of the remaining gasoline with high ethanol content which was distributed into the local marketplace last weekend has been recaptured and replaced with gasoline meeting the state standards,” the company stated, adding, “We have implemented additional measures to ensure the gasoline distributed from our facility meets state specifications.”

It is unclear exactly what percentage of ethanol was in the blends delivered to Minnesota gas stations, but one fuel sample taken by weights and measures officials was shown to contain a 63 percent concentration of ethanol. Had the issue not been noticed and reported as soon as it was, consumer backlash from those who unknowingly filled their nonflex-fuel vehicles with high blends of ethanol could have easily been mistakenly directed at the ethanol industry. Fortunately, there have been no widely reported issues with consumer vehicles as a result of the error.

Magellan has been directed by the Department of Commerce to provide details as to how the error occurred and what it plans to do to ensure it doesn’t happen again, but at press time the report had not yet been made available to the public. Mike Turchi, president of Georgia-based Petroleum Measurement Equipment Co., says that while he’s not familiar with the specifics of this incident, in general, this type of operational malfunction could be caused by any number of equipment failures, although they are rare, he stresses. “There are inventory systems, checks and balances that [are conducted] on a daily basis to ensure that,” he says. “The industry as a whole is very compliant and has very rigid, sound methods to ensure that you catch these mistakes as quick as you can.”

Terminals primarily use one of two methods for ethanol blending: ratio or sequential. Ratio blending consists of side-by-side meters that dispense gasoline and ethanol. Batch controllers pace the flow of ethanol from one meter to create the specified blend based on the amount of gasoline flowing from the main meter. Turchi says ratio blending is typically the preferred method at terminals because it ensures that the correct percentage of ethanol is mixed with gasoline, even if the batch is cut short for some reason. With sequential blending, one meter is used to dispense both ethanol and gasoline. Ethanol is dispensed first, so if the load is stopped before the correct amount of gasoline has entered the tank, the ethanol blend will be higher than intended. “You can fix that, but generally that’s the reason why companies will choose ratio blending over sequential,” Turchi says. Larger terminals may still opt for sequential blending, however, because it is a faster method than ratio blending.

Blending mishaps can also be caused by a flow meter malfunction, a control valve malfunction or an issue within the computer system. Whatever the problem, Magellan took action to immediately correct it, which falls in line with its reputation for being one of the best in the business, Turchi says. “Magellan is one of the best operators in the country and they’ve got some of the best engineers and equipment,” he says. “I suspect that their operating methods are consistent with, if not above, what the rest of the industry does.” 

—Kris Bevill