Organic Nitrogen Compounds and Fuel Instability in Middle Distillate Fuels

Abstract

Previous research studies have implicated polar organic nitrogen compounds in fuel instability. Twenty-one middle distillate fuels were investigated for their organic nitrogen content and to determine if any specific organic nitrogen compound might be linked to fuel instability. The organic nitrogen compounds were isolated by mild acid extraction followed by silica gel adsorption. Three extracts were obtained from each fuel sample: a basic nitrogen extract in methylene chloride (BNC), a nonbasic nitrogen extract in methylene chloride (NBNC), and a nonbasic nitrogen extract in methanol (NBNC). The major constituents of each extract were determined by high-resolution gas chromatography/mass spectrometry (GC/MS). After the compounds were identified for each fuel, the fuels were grouped by ASTM stability values to determine if there was significantly more or less of one type of organic nitrogen compound present that could cause instability. The results of this study showed that there was not a specific organic nitrogen compound responsible for instability, but probably an imbalance in either the basic or nonbasic organic nitrogen compounds that caused a shift in equilibrium resulting in sediment or gum formation. This is important to the military because military fuels can remain in storage tanks for 1 or more years. As fuels are drawn from these tanks, the tanks are subsequently topped off with more recently purchased fuels. In many cases, the mixed fuels are not compatible, resulting in sediment and sludge formation.

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

“…Less than 0.1% of additional organic nitrogen compounds were recovered from the methanol wash. Our laboratory has reported on both methylene chloride and methanol extractions and recovery of polar compounds. [10] This additional recovery was consistent with previous findings. [10] Instrumental methods…”

“…Activated clay would be the cheapest material since the cost of silica gel is three times that of the activated clay. [10] Both methods were effective for organic nitrogen removal with a simultaneous improvement in fuel quality. Although a wide range of organic nitrogen compounds are found in middle distillate fuels, it has been speculated that only specific organic nitrogen species are actively involved in fuel degradation.…”

“…It was found that all of the fuels had a similar suite of organic nitrogen compounds, but differed in that the isomers had different substituted alkyl chains. [10] The United States consumes about 3.0 million barrels of diesel fuel/day (both civilian and military). A petroleum barrel is 42 gallons; thus, 126 million gallons of diesel fuel are consumed daily.…”

“…This laboratory has investigated the distribution and concentration of organic nitrogen compounds in finished diesel fuels from 22 refineries throughout the world, Table 1. [10] The fuels listed in Table 1 for the most part varied from 10 to 20 ppm of organic nitrogen. However, there were two fuels outside this range, the Fischer-Tropsch fuel, with zero ppm organic nitrogen and the tar-sands fuel (Alberta, Canada) with 100-ppm organic nitrogen.…”

Remarkable adsorptive removal of nitrogen-containing compounds from hydrotreated fuel by molecularly imprinted poly-2-(1H-imidazol-2-yl)-4-phenol nanofibers

“…† Instrumentation FT-IR spectra (4000-400 cm À1 ) were run on Bruker, Tensor 27 platinum ATR-FTIR spectrometer. The 1 H NMR spectra of ligands and monomer were recorded on a Bruker 400 MHz spectrometer in DMSO-d 6 . Thermogravimetric analyses of imprinted and non-imprinted nanobers were performed using Perkin-Elmer TGA 7 thermogravimetric analyser (TGA).…”