By Mark Smith
Advanced Fuel Solutions
On July 1 of this year, the maximum allowable sulfur content for #2 home heating oil (HHO) in the Mid-Atlantic area will drop to 500 parts-per-million (PPM). The states of Delaware, New Jersey, and the city of Philadelphia are currently at, or will be required to meet, the 15 PPM sulfur content for #2 HHO on the same date.
As you may recall, the sulfur content of low-sulfur diesel (LSD) in 2006 was 500 PPM. After a transition period, LSD was then required to meet a 15 PPM sulfur content in 2010 to form the present day ultra-low-sulfur diesel (ULSD).
Industry experts expected ULSD to affect lubricity, energy content, materials compatibility, and microbial growth. However, no one anticipated the excessive corrosion that is causing damage to ULSD underground storage tanks (UST).
A task force of industry leaders came together and formed the Clean Diesel Fuel Alliance (CDFA), funding an independent study to determine the cause of accelerated corrosion in USTs containing ULSD. Conclusions from the study point to acetic acid and the introduction of ethanol into ULSD tanks due to switch loading. Switch loading is the practice of loading diesel into a cargo transport tank that had previously held ethanol gasoline. Ethanol, like ULSD, is corrosive by nature.
The EPA is conducting an additional field study on the corrosion in USTs containing ULSD.1
The jury may still be out on all of the potential causes of the accelerated corrosion of ULSD tanks, but the fact remains that today’s ULSD is innately corrosive. ULSD is also prone to increased levels of entrained water, and more susceptible to moisture contamination. The introduction of other moisture-loving corrosive products like ethanol and biofuels compound corrosion issues and set the stage for microbial contamination of USTs. Microbes flourish in water, eat hydrocarbons, and secrete a harmful acidic by-product.
So what are the potential effects of less sulfur in Home Heating Oil?
As the sulfur level of HHO drops to 500 PPM, or as low as 15 PPM in the future, the next generation HHO, much like today’s USLD, will become more corrosive and more susceptible to moisture contamination. Sound storage, transportation, and general housekeeping practices, in addition to an additive treatment program for corrosion and moisture, are essential to dealing with low-sulfur HHO and the ultra-low-sulfur HHO (ULSHO) of the future.
An advanced additive treatment program will do its part to disburse legacy sludge, add lubricity, provide cold flow protection, plus control moisture, corrosion, and stability—helping your business while keeping your customers happy.