Removal Of Organic Nitrogen Compounds Research Articles

The Removal of Organic Nitrogen Compounds from Unstable Diesel Fuels

Fuel storage instability reactions of middle distillate fuel are of interest to the Department of Defense. Unlike civilian fuel, military fuel can remain in storage tanks for one or more years. As fuel is drawn from these tanks, the tanks are subsequently topped off with more recently purchased fuel, and the mixed fuel is not compatible, resulting in sediment and sludge formation. Previous research has shown that certain polar organic nitrogen functional groups involved in instability reactions are difficult and expensive to remove completely during the refining process. Therefore, this study involved the removal of these compounds by four different filtering media. An unstable fuel was treated separately with activated clay, silica gel, amorphous carbon, and iron carbon nanotubes (FeCNT) and the composition of the extracts were analyzed by GC/MS. The results of this study show that some of the media were not only more effective, but selective in removing the organic nitrogen compounds.

The Removal of Organic Nitrogen Compounds in Naphtha by Adsorption

The content of organic nitrogen in the Anqing naphtha was decreased from 4.5 to 0.7 μg·g−1 by 13X molecular sieve, which was impregnated in phosphoric acid. The naphtha/adsorbent ratio of denitrogenation over 13X molecular sieve is 192.2. The suitable conditions for the regeneration is a temperature of 100°C, nitrogen space velocity of 60 h−1, and purging for 3 h, which can achieve long-term operation of nitrogen adsorption. After regeneration by phosphoric acid, the adsorbent activity of 13X molecular sieve recovers to 92.3% of the fresh, and the effective oil/agent ratio is 175.7.

Post-refining removal of organic nitrogen compounds from diesel fuels to improve environmental quality

The purpose of this investigation was to remove the organic nitrogen compounds from petroleum-derived diesel fuels. These nitrogen compounds can cause environmental problems, as well as fuel instability problems that can degrade fuels and affect engine performance. Fuels were treated with two different filtering media, activated clay and silica tel. The methylene chloride extracts from both the activated clay and silica gel were subjected to GC/MS analysis. Close to 99% of the total organic nitrogen compounds were removed. About 60% of the nitrogen compounds identified consisted of pyridines, quinolines and tetra-hydroquinolines made up 26%, while indoles and carbazoles about 10% of the total nitrogen compounds. Of the nitrogen heterocyclics identified, indoles and carbazoles were linked to fuel instability reactions. The proposed method was tested on diesels fuels from a variety of countries and found to remove between 97.8 and 99.9% of the N-compounds. The results of this study showed that both of these filtering materials were effective in removing the organic nitrogen compounds and resulted in fuels that exhibited excellent storage stability. These simple filtering methods can be independent of the refining process and do result in an environmentally cleaner burning fuel.