Removing Organic Nitrogen Compounds From Middle Distillate Fuels with a Catalyst Used as a Filtering Media
Fuel storage instability reactions of middle distillate fuel continue to be of great interest to the Department of Defense. Unlike civilian fuel, military fuel typically remains in storage tanks for one or more years. As fuel is removed from these tanks, the tanks are subsequently filled with more recently purchased fuel. In many cases,the mixed fuel is not compatible, resulting in chemical sediment and sludge formation. This fuel incompatibility can result in chemical degradation reactions that form solids that will plug nozzles and filters and render the entire contents of the storage tank unusable. Previous research has shown that polar organic nitrogen functional groups are involved in fuel instability reactions. These organo-nitrogen compounds are difficult and expensive to completely remove during the refining process; hence, this investigation involved the removal of these compounds employing three heterogeneous catalyst systems and combinations of these systems as filtering media. An unstable fuel was treated separately with Sc(2)O(3), Xu/Sc(2)O(3), fullerene (F), a 1:1 ratio of Sc(2)O(3):(F), and a 1:1 ratio of Cu/Sc(2)O(3):(F). The composition of the filtrates after filtering with the different catalytic systems was analyzed by combined gas chromatography/mass spectrometry (GC/MS). The results of this study showed that after treating the fuel with the catalyst systems, the organic nitrogen compounds detected in the extract were 0.29% carbazoles, 18.2% indoles, and 1.0% for both pyrroles and tetrahydroquinolines, and neither pyridines nor quinolines were detected. This investigation showed that scandium oxide, which is a recycled catalyst, is capable of removing organinc nitrogen compounds from fuels.