Fuel oil is undergoing a makeover. Many states have low-sulfur and ultra-low sulfur fuel statutes coming into play in 2012, and some already have them. Further, percentages of biofuel in fuel oil also seem likely to increase in the not-too-distant future.
Will these developments dictate changes in the use of fuel additives and treatments? Suppliers of additives and treatments, as well as a fuel oil dealer and a major producer of B100 had, as might be expected, differing takes on those issues.
“Lower sulfur product is much more stable, so stabilizers become less important, all things being equal,” said Ed Burke, chairman of Dennis K. Burke, Inc., a fuel dealer in Chelsea, Mass.
“The problem is ASTM has no oxidization stability standard for heating oil and that’s sorely needed,” Burke added, referring to ASTM International, originally the American Society for Testing and Materials.
When it comes to treating fuel oil, “I have a hard time with additives [unless they come] from the refinery or the terminal,” Burke said. “Look at gasoline. The EPA [Environmental Protection Agency] legislated a certain amount of detergency in gasoline and then we were done. That’s how I’d like to see the [fuel oil market] go.”
Bob Tatnall of Fairville Products, Wilmington, Del., which markets Fuel Right additives for preventing sludge and corrosion, said “Ultra-low sulfur heating oil would be the best thing to happen to the heating oil business in decades.”
The lower the sulfur content in fuel oil, the better it is for the operation of a boiler or furnace, he said. “I just think we should embrace it and welcome it.”
But reduced sulfur fuel oil still poses the challenge of sludge, Tatnall said, which plugs and fouls equipment and causes corrosion. He said that his company’s sludge-fighting product, Fuel Right, should be used the same way with reduced-sulfur fuel oil as is prescribed now for conventional fuel oil.
Sludge primarily results from contamination, Tatnall said. That is, as fuel oil is moved from place to place, and stored, water collects in tanks and biological contamination occurs, leading to development of sludge.
“It’s a biological byproduct, primarily,” Tatnall said. “Therefore when you go to a real stable product like ultra-low sulfur diesel the problem of sludge doesn’t go away. No matter how good the fuel is it still gets contaminated and still grows sludge.”
Fuel Management Services (FMS), an additive manufacturer with offices in Toms River, N.J., and Kitty Hawk, N.C., has published literature that states, “We have a solvency issue with [15 ppm] ULSD following LSD into the tank. We need to make sure tanks are clean or ULSD will clean them out for us.”
ULSD is treated with lubricity additives to achieve a minimum level of lubricity per ASTM D975, the supplier said. Some of the additives are oil derivatives of a certain type of tree. These products in the presence of water can form insoluble salts or soaps that can foul filters, usually combining with other insoluble gums, FMS said.
The additive maker recommended checking with operators of fuel terminals to find out what type of lubricity improver they are using – synthetic or organic. “This is a case where the synthetic should be the product of choice,” the company said. Fuel oil dealers seeking to enhance the lubricity of ULSD can use aftermarket improvers, such as Fuel Management Services, to do the job, the company said.
Ultra-low sulfur fuel is turning out to be somewhat less stable than low-sulfur fuel, FMS said. The less stable a fuel is, the more likely it is to produce insoluble particulate, the additive supplier said. The longer fuel is stored the more stability is desired; and stability can be improved with proper additization.
With respect to biofuel, use of treatments and additives will change as the amount blended into fuel oil increases, some said.
Burke suggested that the industry could lobby for biodiesel manufacturers to include a biocide in their product. “It’s come a long way,” Burke said. “It’s better than heating oil, but there is a variance.”
Biofuel does promote or accelerate the growth of sludge, Fairville Products’ Tatnall said. “Anything that works in straight hydrocarbon fuel probably needs to be used at a higher dose rate” with B5 or higher blends, he said.
Fuel Management Services literature states that as the percentage of biofuel grows its properties as a solvent become “excellent.” Clean tanks and lines and an effective organic dispersant go a long way to minimizing fouling of fuel metering systems by insoluble particulates, the supplier said.
But the most significant concern is the impact of cold weather on biofuels, Fuel Management Services’ literature noted. Biodiesel has a higher pour point than diesel and heating oil. As the percentage of biodiesel increases so do the pour point, cold flow plugging point (CFPP), and cloud point, the company pointed out; testing for cold weather operability is one way to minimize surprises, it advised. Fuels can be treated to bring them into the desired operability range, the company said.
More change seems to be in the offing for blending biofuel and conventional heating oil. ASTM International discussed a proposed specification for B6 through B20 heating oil at its meeting in June, said Dave Slade, technical services director for Renewable Energy Group (REG), a B100 producer based in Albert Lea, Minn.
The proposed specification could be balloted in September, said Slade, who serves on two of ASTM’s committees, including the one overseeing heating oil. Slade said the proposed spec could be adopted within two years of balloting. Currently the ASTM spec equates B5 with conventional heating oil.
REG makes B100 from natural fats, oils and greases. It has more than 210 million gallons of owned/operated annual production capacity at biorefineries across the country. The B100 is usually treated for stability prior to blending, Slade said, “and that should carry on and provide good protection in the petroleum fuel as well,” though he said fuel oil dealers might be inclined to use additives to increase stability further.
Biodiesel is an oxygenated fuel, meaning its molecules contain oxygen, Slade noted. For that reason, he said, it does have a little more affinity for water – if water gets into the tank. That happens when condensation occurs in the head space as air is drawn into the tank, as fine cracks let in water, or simply from humidity, Slade said.
“The moisture source is always the environment,” he said. “Biodiesel itself doesn’t bring in any more water, but if you do get water in a tank biodiesel typically will hold a little bit more water in solution. That means you don’t get a water layer in the bottom as quickly.” And that means it takes longer to detect the water, he said.
But at a blended level of B5 the tendency of the fuel to hold water is “really not significant,” he said.