For about a year, various individual tank operators have noticed corrosion issues that some have linked to the ultra low sulfur diesel switchover. This corrosion often takes place within the metal machinery used in storage tanks and may not be obvious through casual maintenance operations. However, as the photographs of the corrosion show, it can be serious.
When these issues began cropping up on the Petroleum Equipment Institute forum, I made a point about a year ago to raise the subject regularly with a variety of both large national ULSD suppliers and end users, such as a major national truck stop operator. Invariably, none of the company representatives I spoke with had noted this as an issue with the product in their operations; nor were there similar concerns to be found in Europe, where various similar ULSD products have been available for, in some cases, over a decade.
Unlike the issues related to ethanol fuels and water in a tank environment, and the early quality control issues with biodiesel, the ULSD examples have been sporadic and scattered geographically and the nature of the problems are not uniform in nature. For example, a filter manufacture I spoke with noted some of the filters sent in to them for examination had particulate rust, and others had some dark contamination of an unknown nature. Nor does a biologic factor seem to be at work. And in some cases the issue has been clearly maintenance in nature, such as improperly grounded machinery.
Groups such as PEI and the Petroleum Marketers Association of America are taking on some formal research to see if the issue is real or perhaps a case of attributing routine maintenance issues to the coincidental adoption of ULSD.
We will provide more coverage on this in coming months as the studies progress.
While the verdict is out on ULSD itself, we do have a correction to run regarding our ULSD lubricity article that ran last month. Several of the test protocols related to biodiesel noted by Jerry Sava in the article “Taking the Mystery out of Lubricity” were incorrect. Sava has acknowledged the errors.
In a letter to the editor, Robert S. Cerio, with Ocean State Energy Resources, wrote, “Mr. Sava refers to ASTM D6751 as the protocol for the HFRR test for lubricity in diesel. D6751 is the ASTM full range analysis for B100 biodiesel. He then goes on to reference D275 as the HFRR lubricity test protocol with for diesel fuel, in summary he references D6751 once again (the B100 biodiesel analysis protocol) and in the same sentence calls the HFRR protocol D27. The proper ASTM analysis protocol for lubricity in diesel is D6079.”
Cerio contends, and in retrospect Sava agrees, that the lubricity concerns with biodiesel made from non-soybean sources were overstated. He said, “A B2 blend of biodiesel in diesel fuel regardless of the feed stock that it is made from will yield lubricity properties that exceed the Original Equipment Manufacturers, OEM requirements. It is the ultimate diesel fuel lubricity enhancer and it is environmentally friendly.”
Sava noted he had some personal experience with smaller-scale biodiesel producers that were not producing a certified product, and that products that pass ASTM certification should be fine regardless of feedstock.