Recent advances in the science and technology of ultra low sulfur diesel (ULSD) production

Kerogen origin, evolution and structure

Sulfur compounds represent one of the most common impurities present in the crude oil. Sulfur in liquid fuel oil leads directly to the emission of SO2 and sulfate particulate matter (SPM) that endangers public health and community property; and reduces the life of the engine due to corrosion. Furthermore, the sulfur compounds in the exhaust gases of diesel engines can significantly impair the emission control technology designed to meet NOx and SPM emission standards. The research efforts for developing conventional hydrodesulfurization and alternative desulfurization methods such as selective adsorption, biodesulfurization, oxidation/extraction (oxidative desulfurization), etc. for removing these refractory sulfur compounds from petroleum products are on the rise. Research laboratories and refineries are spending huge amounts of money in finding a viable and feasible solution to reduce sulfur to a concentration of less than 10 mg l−1. This paper reviews the current status in detail of various desulphurization techniques being studied worldwide. It presents an overview of novel emerging technologies for ultra-deep desulfurization so as to produce ultra-low-sulfur fuels.

An evaluation of desulfurization technologies for sulfur removal from liquid fuels

Ultra-deep desulfurization and denitrogenation of diesel fuel by selective adsorption over three different adsorbents: A study on adsorptive selectivity and mechanism

The molecular representations of coal – A review

From coal to single-stage and two-stage products: A reactive model of coal structure

A heavy hydrocarbonaceous oil feed is hydrogenated in a two-stage process by contacting the oil with hydrogen in the presence of added dispersed hydrogenation catalyst, suspended in the oil, and porous solid contact particles. At least part of the normally liquid product from the first stage is hydrogenated in a second stage catalytic hydrogenation reactor.

Two-step hydroprocessing of heavy hydrocarbonaceous oils

Hydrodesulfurization (HDS) and hydrodenitrogenation (HDN) of a commercial medium cycle oil (MCO) were performed over a commercial NiMoS/Al2O3 catalyst through both single- and two-stage hydrotreatments at 340°C. The reaction atmosphere was replaced with fresh hydrogen, with or without additional dose of catalyst, for the second-stage treatment to determine the mechanism of reduced activity. Sulfur and nitrogen molecular species in MCO were identified by gas chromatography with an atomic emission detector (GC-AED) to quantify their respective reactivities and susceptibilities to inhibition. Under single-stage (30 min) conditions, the reactivity orders in HDS and HDN were BT>DBT>4-MDBT>4,6-DMDBT and In>alkylIn>Cz>1-Cz>1,8-Cz, respectively. Additional reaction time beyond the initial 30 min, without atmosphere or catalyst replacement, gave little additional conversion. Replacement of the first-stage gas with fresh hydrogen strongly improved second-stage conversions, particularly those of the more refractory species. An additional dose of catalyst for the second stage with hydrogen renewal facilitated additional HDS of dibenzothiophene (DBT), 4-monomethylated DBT (4-MDBT), and 4,6-dimethylated DBT (4,6-DMDBT) which was independent of their initial reactivity, while HDN of carbazole (Cz), 1-Cz, and 1,8-Cz was improved, the least reactive species being most denitrogenated. Such results suggest the strong inhibition of the gaseous products H2S and NH3. The catalyst deactivation was most marked with HDN of 1,8-Cz, suggesting that acidity is essential to the reaction. H2S is suspected to inhibit both S elimination and hydrogenation of S and N species at the level of concentration obtained during desulfurization. The inhibition by remaining substrates may still influence the HDS and HDN of refractory species in the second stage, even if their contents were reduced by the first stage. It appears very important to clarify the inhibition factor of all species on the refractory sulfur species, and to determine the inhibition susceptibility of these species at their lowered concentration to enable the effective achievement of 50 ppm sulfur level in distillate products. The conversions of inhibitors must be accounted for during reactions. Catalyst and reaction configuration to reduce the inhibition by the gaseous products are the keys for deep refining.

Inhibition and deactivation in staged hydrodenitrogenation and hydrodesulfurization of medium cycle oil over NiMoS/Al2O3 catalyst

Nitrogen molecular species in several gas oils were analyzed by gas chromatograph with an atomic emission detector (GC-AED) and mass spectrometer (GC-MS) Nitrogen species in gas oils were divided through acidic extraction into basic species (such as aniline, quinoline, benzoquinoline, and their derivatives) and nonbasic species (such as indole, carbazole, and their derivatives) To be mostly identified, their distribution depended on the cutting point and origins of gas oils Denitrogenation reactivities of nitrogen species in gas oils were followed in the hydrotreating reactions at 340 °C under 5MPa of H2 to quantify by GC-AED their respective reactivities in GOs The reactivities orders and reactivity dependence on their chemical structures and matrix compositions are discussed on molecular bases The reactivity order was found as indole > methylated aniline > methylated indole > quinoline > benzoquinoline > methylated benzoquinoline > carbazole > methylated carbazoles The number and position of methy

Identification and Reactivity of Nitrogen Molecular Species in Gas Oils

A heavy hydrocarbonaceous oil feed is hydrogenated in a one or two stage process by contacting the oil with hydrogen in the presence of added dispersed hydrogenation catalyst, suspended in the oil, and porous solid contact particles. In the two stage process, at least part of the normally liquid product from the first stage is hydrogenated in a catalytic hydrogenation reactor.

John H. Shinn

Papers

From coal to single-stage and two-stage products: A reactive model of coal structure

Two-step hydroprocessing of heavy hydrocarbonaceous oils

Inhibition and deactivation in staged hydrodenitrogenation and hydrodesulfurization of medium cycle oil over NiMoS/Al2O3 catalyst

Identification and Reactivity of Nitrogen Molecular Species in Gas Oils

Hydroprocessing of heavy hydrocarbonaceous oils