A high level of hydrodenitrogenation (HDN) is required to achieve a desirable conversion of other hydroprocessing reactions. This results from a strong adsorption of nitrogen‐containing compounds on catalytic sites that slows down the hydrogen activation process and hinders the adsorption of other reactants. Studies on model compounds and real feeds indicate that less than 50 ppm of nitrogen in the feed can poison catalytic sites. Kinetic studies determined adsorption constants of various nitrogen‐containing compounds and concluded that at least four different catalytic sites are required to interpret experimental observations in contrast with a dual site site≅concept, which only considered two sites. The advancements in experimental techniques allowed identification of products formed during very early stages of hydrodenitrogenation. These results confirmed that the removal of the amino group from saturated amines, as the last step in hydrodenitrogenation, is governed by the type of carbon to which the a...

Hydrodenitrogenation of Petroleum

High-resolution (100 000 < m/Δm50% < 250 000, in which Δm50% denotes mass spectral peak full width at half-maximum height) electrospray ionization Fourier transform ion cyclotron resonance positive-ion mass spectra of unprocessed (and processed) diesel fuels resolves approximately 500 (and 200) chemically different constituents over a mass range from 200 to 452 Da, with as many as 6 resolved elemental compositions at a given nominal mass. Molecular formulas were assigned from accurate mass measurement to within ±1 ppm. Compound types were identified by Kendrick mass analysis. On the basis of the experimental behavior of model compounds, electrospray ionization was found to ionize selectively basic pyridine homologuescompounds responsible for deactivation of hydrotreatment catalysts and instability of fuels during storage. Compound classes identified in the unprocessed diesel fuel include those containing N, N2, NS, NO, N2O, O2, and SO and, in the processed diesel, N, N2, NO2, and SO. Comparison of unproce...

Elemental Composition Analysis of Processed and Unprocessed Diesel Fuel by Electrospray Ionization Fourier Transform Ion Cyclotron Resonance Mass Spectrometry

The activity of the conventional catalysts during hydroprocessing results from the ability of Mo(W)S2 to adsorb and activate hydrogen. The optimum of hydrogen adsorption occurs at the S/Mo(W) ratio of about 1.95. This is consistent with removal of the corner and edge sulfur atoms leading to the formation of the sulfur anion vacancies. The heterolytic dissociation, involving both metal and sulfur ions, is the predominant mode of hydrogen activation. It leads to the formation of metal–H and S–H moieties. The homolytic dissociation, occurring on the sulfur ion pairs, is much less evident. For the supported catalysts, the amount of the adsorbed hydrogen per unit of Mo(W) is significantly greater. This results from the spillover of the active hydrogen from the active phase on the support. The surface hydrogen can migrate back from the support to the active phase. Promoters, such as Ni and Co, increase the rate of adsorption, whereas their effect on the total amount of the adsorbed hydrogen is much less pronoun...

Hydrogen activation by transition metal sulfides

Synthesis and Activity of a New Catalyst for Hydroprocessing: Tungsten Phosphide

Coal is one of the world's most chemically complex natural mixtures, whose composition varies with origin and age. Its combustion yields environmentally relevant “greenhouse” gases such as SOX and NOX. Here, for the first time, we apply electrospray ionization (ESI) Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) to the analysis of Illinois No. 6 and Pocahontas No. 3 pyridine coal extracts. With the aid of Kendrick mass scaling, the elemental compositions can be sorted into different homologous series according to compound “class” (number of various heteroatoms) and “type” (rings plus double bonds). Many more species and classes were detected in Illinois No. 6 coal than in Pocahontas No. 3 coal. Illinois No. 6 coal contains mainly oxygen- and sulfur-containing classes; conversely, Pocahontas No. 3 coal contains nitrogen-containing classes. Both coals share O2 and NO2 classes. Pocahontas coal exhibits much greater aromaticity (more rings plus double bonds) and less alkyl substitutio...

Resolution of 10 000 Compositionally Distinct Components in Polar Coal Extracts by Negative-Ion Electrospray Ionization Fourier Transform Ion Cyclotron Resonance Mass Spectrometry

M. Jian

Papers

Mechanism and kinetics of hydrodenitrogenation