Ultra-Low Sulfur Fuel Oil Effects

As the industry looks forward to widespread use of ultra-low sulfur fuel oil, it is facing a deadline in at least one Northeastern state that might be difficult to meet. New York State has passed a mandate for use of the fuel starting in 2012.  But field and lab testing has turned up a possible problem: the fuel might not be fully compatible with seals on residential oil pumps.

The technical concerns need to be resolved before ultra-low sulfur (ULS) fuel oil   goes into wide distribution, John E. Batey, technical director for the Oil Manufacturers Association (OMA) said in a report to the association.

‘We do have a bit of an issue here,” Batey said in an interview with Fuel Oil News. The potential problem with seals on residential oil burner pumps was discovered during in-depth field tests sponsored by the New York State Energy Research and Development Authority (NYSERDA) and in lab tests at Brookhaven National Laboratory. Testing turned up the possibility of shortened lifetimes of the seals.

This increases the potential for fuel oil releases in homes, Batey reported, which needs to be fully evaluated and corrected before widespread use of ULS in residential oil burners. Research is ongoing, he said, but is not likely to be completed until late in 2012 – nearly two years from now.  

The ULS heating oil field demonstration in homes funded by NYSERDA was headed up by Batey and personnel at Brookhaven National Laboratory, including Roger McDonald, a senior project engineer at Brookhaven. (McDonald, well-known for his research during a decades-long career at Brookhaven, died in December.)

The field test involved 100 houses using ULS (15 ppm) fuel oil and a control group of another 100 using conventional fuel oil. The goal was to evaluate the benefits and potential operational problems associated with burning ULS heating oil in homes.

The tests indicated potential shortening of pump seal lifetimes both with ULS heating oil and with ULS/B5 fuel oil blends. Industry support is growing for accepting a ULS/ B5 blend as a standard fuel in the near future, Batey noted. Pumps with viton seals (developed for biofuel) failed quickly ‘ ‘on the order of a year,” Batey said ‘ both in the lab and in the field.

Conventional nitrile seals that are frequently found in home oil burners may last only four to five years, compared to eight to 10 years with heating oil containing normal levels of sulfur.

Even shorter lifetimes were observed in pumps tested with ULS/B5 blends. Of four pumps tested, two failed after the equivalent of 1.5 to 2.5 years of operation, Batey reported. ‘This is a concern as B5 blends are approved by UL [Underwriters Laboratories] for residential oil burners,” Batey reported.

An extension of the project has been approved by NYSERDA that will allow all 100 fuel pumps from the ULS test group to be collected. The pump seals, which by now have gone through two years of operation with ULS heating oil, will be examined to determine their condition.

OMA is supportive of the use of ULS heating oil, Batey noted.

The emissions performance of ULS is very similar to that of natural gas, Batey said. ‘That’s why we have to follow up on the pump seals” ‘ because that level of emissions performance by ULS would be a powerful competitive factor in favor of fuel oil.

Batey reported that Brookhaven has also carried out an in-depth evaluation of particulate matter (PM) emissions from residential oil, gas, and wood heating equipment. The findings are noteworthy, Batey said, because the Environmental Protection Agency (EPA) on June 4, 2010, proposed new air emission standards for commercial, institutional, and industrial oil burners that could seriously restrict the sales of new oil heating equipment. 

The evaluation by Brookhaven, funded by NYSERDA, resulted in some important findings related to oil burner emissions and the impact of fuel sulfur content, Batey said.

He summarized them in a report to the OMA:

·        PM emissions from oil burners are very low compared to wood burning equipment

·        Ultra-Low Sulfur Oil (15 ppm) and biofuel blends in heating oil produce PM emissions approaching zero and are similar to natural gas burners.

·        PM emissions are becoming very important as air emission control groups are now focusing on PM health effects and environmental haze

·        Oil heating equipment can be one of the lowest PM emissions sources.

·        When combined with the reduced global warming potential produced by biofuel blends (even with biofuel blend as low as 10% to 20% in heating oil), oil burners using ULS heating oil can be shown to be the environmental fuel of choice for home heating. 

The Brookhaven findings on particulate matter confirm low emissions levels for flame retention head burners at 0.00397 pounds of PM per million Btu of fuel consumed. Low sulfur (LS) heating oil reduces PM emissions by oil burners by a factor of three. ULS oil reduces oil burner PM emissions by a factor of 40. This is approaching the level of zero PM emissions and is negligible when compared to most other combustion sources, Batey said. Lower PM emissions have important benefits for fuel oil marketers and homeowners, as less frequent boiler and furnace cleanings are needed as the fuel oil sulfur level is reduced. It is important to note that conventional oil burner PM emissions produce only about six ounces of soot a year when properly adjusted, Batey said. PM levels for ULS heating oil are 40 times lower or about one-seventh of an ounce per year, Batey said.

Wood pellets produce less PM than most other wood burning equipment, but still about 15 times more than No. 2 heating oil and 580 times more than oil burners using ULS fuel, according to the work done by Brookhaven, Batey said.

‘These are very important findings because they prove that residential oil burners produce much lower levels of PM than the lowest emitting wood burning equipment, and ULS heating oil produces PM emissions that are comparable to natural gas,” Batey wrote in his report to OMA. ‘This places oil burners using ULS fuel into the lowest emission category of all combustion equipment.”

Batey further noted that natural gas utilities are relying on energy prices and claiming environmental benefits to convert homeowners to gas. The results from Brookhaven, a national laboratory, help to disprove the environmental claims by gas companies and question the validity of the recently proposed EPA PM and CO regulation impacting oil burners.