Standardization News

ASTM Tests Ensure Fuel Quality

Test methods developed by ASTM’s petroleum committee support the quality, distribution, and delivery of petroleum products. Here’s a look at some of the issues ASTM’s largest committee must resolve to meet a very high level of user expectations.
By: 
Rick Carter

Beyond cost, most of us don’t give a lot of thought to the gasoline, diesel fuel, motor oil, or liquid propane we purchase. Once the items reach the gas station, retail shelf, or other distribution channel, they’re assumed to be safe, effective, clean, and ready to use. And they just about always are.

But how they get that way is no accident. And it has much to do with ASTM’s committee on petroleum products, liquid fuels, and lubricants (D02).

D02 is ASTM’s largest technical committee, with nearly 2,500 members. It’s also one of its oldest, founded in 1904. D02 members include representatives from across the oil industry — refining through product manufacturing — as well as original equipment manufacturers, laboratories, test equipment makers, and others.

One goal almost all of these stakeholders share is to offer reliable test methods that manufacturers and distributors can use to help ensure the efficacy of petroleum products through end use.


 



Test Methods

The specifics of that stakeholder effort are found in the text of the more than 800 test methods D02 subcommittees have created. The standards cover fuel octane, fuel contamination, oil viscosity, fuel- and oil-blend specifications, corrosion-causing agents, and environmental considerations, among many others. Some standards have existed many years, and all are routinely subject to review and update, usually based on requests from the field.

“A lot of these requests come from industry, which typically has a problem they need solved,” says Larry Tucker, vice president of business development for Metrohm USA, a Switzerland-based maker of test instruments for chemical analysis. A member of five D02 subcommittees and vice chairman of two (on elemental analysis and analysis of liquid fuels and lubricants), Florida-based Tucker serves the needs of his company’s customers and the greater oil industry through ASTM by contributing to fuel test methods.

His recent work with ASTM, for example, has involved methods to test for moisture in ethanol and ethanol fuel blends. He has also helped complete a significant new test method for crude- and shale-oil acidity that will update longtime ASTM test standard D664. Like all D02 efforts, Tucker’s are as critical to petroleum product reliability as they are largely unknown to end users who benefit from them.

Preventing Corrosion

Improving acid-level tests for crude and shale oil help prevent corrosion and the havoc it can cause at the refinery and farther down the line. “The acids in crude oil contain naphthenic acid,” says Tucker, “which is distilled in the refining process and causes pipeline corrosion.” And as corrosion at the refinery builds, plant reliability drops and maintenance costs rise.

To control corrosion, an accurate and repeatable way is needed to measure naphthenic acidity content. “The resulting acidity number — low or high — is important to know because not every refinery can safely process acidic crude,” says Tucker. Furthermore, as portions of crude production are diverted to make motor-oil base stock, only low acid levels can be accepted. After four years of work, ASTM recently approved a test method for assessing the acid number of crude oils and petroleum products using catalytic thermometric titration (D8045). The updated acid-level test not only better helps refiners test for acids, it gives them a previously unused technique — thermometric titration — for doing so.

Helping to craft D8045 was one of many milestones for Tucker in what has been a long relationship with corrosion issues. One of his first ASTM projects, for example, resulted in the committee’s approval of a test method for determining sulfate and inorganic chloride in ethanol and butanol (D7319) in the early 2000s when the use of those fuels was growing. “This was needed because chloride can cause corrosion in the fuel,” he says, “and too high a concentration of sulfate can clog fuel-injector valves.”

Tucker continues his anti-corrosion work with research for a new method to measure organic halides in crude. The halides break down to form hydrochloric acid, “which corrodes the process and eats away the [cracking-process] catalyst,” he says. “It’s one more reason why corrosion is such a big issue for refineries.”

Perfecting Motor Oil

Another big issue, for end users in this case, is motor oil performance. The United States was one of the first countries in the world to grasp the importance of lubricant testing for oil viscosity and other issues, says Gregory Miiller, a member of five D02 subcommittees and vice president of operations for the Savant Group, a Michigan-based firm that includes test-equipment maker Tannas Co. In the last century, engine failures were often “due to problems directly related to what was put in them,” he notes. Despite years of research on the topic, OEMs knew more work was needed, adds Miiller, especially after incidents like the one that occurred nearly 40 years ago in Sioux Falls, South Dakota.

“In the winter of 1980-81,” says Miiller, “a high number of automobiles suddenly stopped running after being started on a cold morning. Many engines were found to be seized and would not restart.” All were the same type of vehicle, all still on factory warranty, “and all were using factory-filled oil, so after getting many phone calls, that OEM wanted to figure it out.”

The problem centered around what Miiller calls the previous evening’s “peculiar cooling rate” after sunset, which strayed from a normal fast rate of cooling to a much slower rate. “This induced a gel-like structure in the oil in these cars,” says Miiller, noting that the propensity for such an occurrence could not have been detected by viscosity testing available at the time. “So these engines naturally failed.”

The Savant Group and Miiller’s colleagues in the D02 subcommittee on flow properties solved the problem by developing what became the scanning Brookfield technique and, eventually, the ASTM method for testing the viscosity/temperature dependence of lubricating oils (D5133). This standard, which is updated regularly to keep up with changing technologies and advanced engines, allows oil makers and OEMs to more accurately test motor oil viscosity under a wide range of temperatures, and it has been written into specifications around the world.

Oil viscosity is also studied for its effect on fuel economy, especially with regard to recent U.S. Environmental Protection Agency efforts that encourage OEMs to design tight-tolerance engines that can operate successfully using low viscosity oils. “To accomplish this, tests were needed to address two things,” says Miiller. “One, that a lower viscosity oil could contribute to better fuel economy, and two, that a lower viscosity oil could withstand the harsh conditions of the engine and still protect it during operation.”

A particular concern was temporary shear loss, which happens when a mechanical process causes molecules to be distorted and elongated. This results in the sudden and usually temporary degradation of an oil’s viscosity. Where tolerances are tight, such as in an engine’s journal bearing, shear rate increases and reduces the oil’s ability to lubricate.  “And if viscosity levels drop low enough, you may have engine trouble,” says Miiller. So the Savant Group approached ASTM and, with other stakeholders in Committee D02, created the tapered bearing simulator test (D4683), which simulates the journal bearing in an engine. “The industry adopted it,” says Miiller, “and has since used it to shape tests for dropping oil viscosities even further,” in anticipation of regulations calling for ever greater fuel efficiencies.

The Microbe Mystery

Like bacteria that cause disease in humans, microbes are virtually omnipresent in all petrochemical products. But less is known about these often troublemaking petroleum-based microbes than their human-hosted counterparts. “We’re still in a phase where we don’t know what we don’t know,” says Fred Passman, a member of five D02 subcommittees and founder of BCA, Inc., a New Jersey-based company that offers microbial-contamination control consulting services. “We do know that a variety of bacteria and fungi can infect fuel systems. They produce acids that make fuels more corrosive, and they produce detergent-type molecules we call biosurfactants, which help bring water into fuel. And because they directly attack different fuel molecules,” he says, “they can degrade the fuel’s performance properties, so they can contribute to many different types of fuel-product and infrastructure damage.”

Passman acknowledges that research on the topic is “limited by our methods because each generation’s information is largely biased by the available technology for doing the research.” Despite the many thousands of papers written on fuel microbiology, he says, “We have just now entered an era where we have new methods and a chance to develop what we call a genetic approach for looking at microbial contamination in fuel systems.”

Though microbes thrive only in water — not in fuel molecules — water/microbial contamination is possible throughout most of the petroleum-product infrastructure, from oilfield to storage tanks. Water accumulates in fuel and other petroleum products immediately following the superheated cracking process at the refinery. “And by the time it reaches the bulk tanks at the refinery, you can already see significant microbial contamination,” says Passman. This has much to do with the fact that the product is typically delivered warm, and cooling causes water to condense in the tank. “And because all tanks have to breathe,” he notes, “atmospheric moisture is brought in as product is drawn out.”

This cycle presents a special challenge for those who deliver and store “spark-ignition” fuels like gasoline and others. Though ASTM tests for the presence of microbial contamination in fuels are available (including a test for determining the viable aerobic microbial content of fuels and water (D7978), they’re not used often enough, says Passman. “People seem to believe that if they don’t look, it can’t be there,” he says. “So the first time they know they have an issue is when their tanks start leaking.” Pre-leak signals — such as a clogged dispenser pump filter at a retail gasoline station — often go unnoticed, he adds, even though clogs noticeably reduce the rate of fuel pumped. To correct such situations, fuel can be “polished” by additional filtration, says Passman, and treated with biocides, preferably based on reliable test data to determine the need for it.

The Work Follows the Future

Committee D02 members express great faith in the group’s ability to successfully address the broad and evolving needs of the petroleum products community. “ASTM is an excellent forum for discussion among experts about how to maintain and improve the text of the test methods,” says Ian Mylrea, a member of 15 D02 subcommittees, and R&D manager at Stanhope-Seta, a United Kingdom-based maker of precision test equipment. High on his list of future D02 challenges are those involving contamination and compatibility.

“As refining moves farther from where fuel is actually sold and used, and more fuel is being used, the amount shipped over larger distances increases,” says Mylrea. “So the longer it’s on board a vessel or in a tank or distribution network, the more opportunity there is for it to change and deviate from its specification or to be contaminated.” He also expects that environmental targets will introduce ever higher levels of renewable-source material to fuel blends, “which, experience shows, can cause unexpected problems,” he says. “And how these trends affect standardization is that the scope of some methods — what they are able to measure — may no longer be appropriate, so new methods need to be developed or old methods need a revamp and new precision.”

Still, most end users will likely remain blissfully unaware of such dedicated, behind-the-scenes efforts — a condition that doesn’t seem to faze D02 members. “We certainly won’t win a Nobel Prize for this work,” says Tucker, “not even a mention. But,” he adds, “we do know it’s very necessary to help make things better for the next generation.” //

ASTM to Launch Petroleum Lab Technician Certificate Program

ASTM International is preparing to offer a Petroleum Lab Technician Certificate. Based on a series of self-guided, area-specific online training modules, it will complement ASTM’s existing Petroleum Lab Technician Training modules by providing third-party proof of a technician’s knowledge of an ASTM test method.

Certificate program modules will feature an overview of key concepts, a tutorial on the procedure, a video demonstration of the procedure, and a test at the end. The certificate will enhance an organization’s internal quality assurance and personnel development as well as provide security in commercial transactions.
ASTM expects to start officially issuing certificates in early 2017 to those who successfully complete the modules. A certificate will be valid until the relevant standard is updated.

For more information, contact Sales.

Alert: Proficiency Testing Program Helps with New EPA “Tier 3” Compliance

You may have heard that the U.S. Environmental Protection Agency’s has issued new “Tier 3” requirements aimed at driving down sulfur content in exhaust. This means that each piece of lab equipment used for gasoline tests will have to be tested at least three times per year.

The good news is that ASTM International has modified its Proficiency Testing Program to help you stay in compliance, starting with the Feb. 1, 2017, renewal cycles.

Contact us today to see how we can help:
Amy Meacock
ASTM International
(tel +1.610.832.9688)

Issue Month: 
November/December
Issue Year: 
2016
COMMITTEE: 
D02