Does Your Diesel Fuel Meet Emissions Standards?

Sulfur (S) occurs naturally and abundantly in the environment. At one time it was mined from underground deposits by what is called the Frasch process. According to The Sulphur Institute, sulfur was extracted by the Frasch process up until the late 20th century but as of 2011, the only operating Frasch mines worldwide were in Poland. Now most sulfur is recovered as a by-product of oil and gas production. In fact, the U.S. Department of Energy (DOE) National Energy Technology Laboratory (NETL) website states that in 2011, 8.1 million tons of elemental sulfur was produced, mostly from petroleum refining, natural gas processing and coking plants.

Sulfur is a very valuable element in the agriculture industry, where it’s used as a fertilizer to provide essential nutrients to promote plant growth and increase crop yields. It’s also one of the most important industrial raw materials, with numerous uses in industries including chemical, manufacturing, metals, pharmaceutical, and water treatment.  

But one industry in which sulfur is not welcome is fuel. Diesel fuel is extremely efficient, but it produces greenhouse gas emissions due to its sulfur content. Sulfur was once present in large amounts in diesel fuel and gasoline, but in 2006 international regulations started requiring a reduction in the amount of sulfur in diesel fuel in the transportation sector, meaning the heavy-duty trucks, construction and agricultural equipment, locomotives, and commercial marine vessels that use the largest amounts of diesel fuel.

Starting in 2007, U.S. EPA standards required that sulfur content be reduced from 500 parts per million (ppm) to 15 ppm (the limit is 10 ppm in the EU), and that consumers with 2007 or later model year diesel vehicles should only fuel them with ultra low sulfur diesel (ULSD). ULSD directly reduces vehicle exhaust emissions, especially sulfur dioxide and sulfate particulate matter emitted from combustion. According to the EPA, ULSD is a cleaner-burning diesel fuel that contains 97% less sulfur than low-sulfur diesel (LSD) and functions more effectively with pollution control devices that can be damaged by sulfur. The EPA plans to roll out similar rules for gasoline by 2017.

Countries all over the world that have adopted the strictest vehicle emissions standards now require a steady supply of ultra low sulfur fuels. The U.S. is one of a few countries that supplies ULSD to the international market.  

Refined product pipelines and terminals play a major role in the distribution of motor fuels. Many pipelines use a common system to distribute a wide variety of refined products with dramatically different sulfur content. Terminal operators need to conduct careful and continuous analyses of their product pipelines to be certain they are delivering ULSD that meets environmental regulations. These operators use sulfur analyses to:

• Determine sulfur content of fuels entering the pipeline system.
• Enable rapid corrective action through identification of sulfur contamination sources.
• Prevent downgrading of valuable ultra low sulfur fuels by enabling fuel blending.

Online technology is available to provide fuel distributors with the data they need to be sure their shipments meet customer specifications and regulatory requirements. Study data is available to demonstrate how a field sulfur analysis system provides a simple, straightforward means of determining grab sample sulfur content.