Total Nitrogen (TN) stands for the sum parameter of all organic and inorganic nitrogen compounds. Trace levels (0.02 – 10.000 mg/kg or ppm by weight) of Total Nitrogen are measured with an elemental combustion analyzer according to Chemiluminescence detection technique. Total Nitrogen in fuels (NO2) pollutes the environment. It is corrosive to steel and poisons catalysts. Nitrogen compounds are more thermally stable compared to sulfur compounds and is often concentrated in heavier petroleum fractions and residues. Examples of Organic Nitrogen compounds that contribute to the Total Nitrogen number in petroleum products are Pyridines, Quinolines and Carbazoles. Common ASTM methods for nitrogen testing include: ASTM D4629, ASTM D5762, ASTM D7184, and D6069. The Nexis TN total nitrogen analyzer provides a reliable and robust solution for labs.
ASTM Method D4629 is commonly used for the determination of Nitrogen found in liquid hydrocarbons. The method is used for
matrices with total Nitrogen content under 100mg/kg. Common matrices for this method include naphthas, distillates and oils. This
application will examine total Nitrogen content using small sample volumes.
Vacuum Gas Oils (VGOs) are the heavy oils left after petroleum distillation. VGOs have a viscous matrix and high boiling points. The EST
Analytical TN 7000 has an injection port designed to maintain the injection port temperature at 500°C, while the autosampler tray can be
fitted with a heater. These features aid in making the TN 7000 ideal for the examination of total Nitrogen in VGO samples.
In 2000, the EPA implemented the Tier 2 Gasoline Sulfur program. This program reduced the allowable sulfur content in gasoline to 15ppm and NOx content to 0.07g/mile. The Tier 2 program was initiated out of the Clean Air Act requirement of the Environmental Protection Agency. In 2017, a Tier 3 program was applied requiring even lower sulfur and nitrogen content in gasoline and diesel. The new emission standards combined with the lowered sulfur content will reduce much of the toxic emissions including nitrogen oxides from motor vehicles. Due to these new regulations there is a need for better analysis of low level Nitrogen and Sulfur.
Crude oil is composed mainly of hydrocarbons mixed with a variation of nitrogen, sulfur and oxygen. The differences in the nitrogen, sulfur, and oxygen content can be attributed to where the crude oil originates. After drilling, crude oil is usually refined in order to create fuel, lubricants, etc. Due to the use of processing catalysts in the refining method, trace amounts of sulfur and nitrogen can be very detrimental. Thus, determining the nitrogen and sulfur content is very important. This application will examine total sulfur and nitrogen in light hydrocarbon samples using the NexiS combustion elemental analyzer complete with a new and novel multilayer combustion tube.