Desulfurization Of Model Diesel Research Articles

Competitive Adsorption in a Multicomponent Diesel System Using Nickel Oxide/Activated Carbon

Nickel oxide, which acts as an intermediate Lewis acid, was loaded onto activated carbon (AC) to enhance the adsorption selectivity of AC in the desulfurization of model diesel. The total sulfur adsorption capacity increased from 2.46 to 4.42 mg-S·g adsorbent–1 and the total sulfur removal increased from 46.8 to 84.5% using the AC and Ni(10%)O/AC adsorbents, respectively. Multicomponent isothermal modeling showed that the incorporation of NiO onto AC significantly improved the synergistic interactions between the thiophenic compounds while mitigating competitive interactions between the more steric 4,6-dimethyl dibenzothiophene (4,6-DMDBT) and 4-methyl-dibenzothiophene (4-MDBT) compounds. The mitigation was attributed to new adsorbate-specific sites created by loading NiO on AC. Spent adsorbent characterization and pyridine adsorption-IR analysis suggested that higher desulfurization performance of the Ni(10%)O/AC adsorbent was attributed to an increase in the adsorbent’s Lewis acidity upon loading with NiO, leading to increased Ni–S acid–base interactions, in addition to π-complexation.

Effect of the calcination temperature on SnO2-MoO3 crystal structure and catalytic activity in desulfurization of model diesel

Fuel’s sulfur content should be controlled to prolong catalytic converters and infrastructure life and improve air quality and human health. Catalytic sulphur oxidation is widely used for fuel refining. In this work, a novel SnO2-MoO3 catalyst was synthesized by the inverse sol–gel method for oxidative desulfurization of dibenzothiophene (DBT). The catalyst was characterized by thermogravimetric analysis (TGA), X-ray diffraction (XRD), scanning electron microscopy (SEM), N2 adsorption–desorption, and Fourier-transformed infrared spectroscopy (FTIR). Calcination temperatures 150–650 °C significantly affected the catalyst’s thermal stability, textural properties, and catalytic efficiency. The optimal calcination temperature of 450 °C resulted in a 99.6 % conversion of the DBT to dibenzothiophene sulfone. Kinetic investigations revealed a pseudo-first-order reaction with a 36 ± 4 kJmol−1 activation energy. The catalyst demonstrated excellent catalytic activity and reusability and thus has huge potential in industrial catalytic desulfurization. This catalyst promises improved air quality, public health, long catalytic converter life, and reduced infrastructure degradation.

Non-catalytic desulfurization of model diesel using synthesized biodegradable ionic liquid

ABSTRACT The conventional processes generally used by petroleum refineries for eradication of sulfur compounds from diesel, namely, diesel hydrotreating is associated with the problem of high cost in terms of energy consumption, catalyst regeneration, etc. The present work has spotted a diesel desulfurization process at ambient temperature (25°C) without using any catalyst. Solvent extraction was applied to eliminate heterocyclic sulfur compounds from model diesel using a novel ionic liquid, which was synthesized from basic raw materials and characterized by common techniques like Fourier Transform Infrared (FTIR) spectroscopy and Nuclear Magnetic Resonance (NMR) spectroscopy. A preliminary biodegradation study of the synthesized ionic liquid revealed 49.98% biodegradability after 35 days. The compounds present in the synthesized ionic liquid are 1,3-diethyl-1H-1,2,3-triazol-3-ium acetate ([Etim][OAc]), 1,3-diethyl-1H-imidazol-3-ium ([Eiim][OAc]), and 1-ethyl-3-methyl-3H-pyrazol-1-ium acetate ([EMpim][OAc]). The maximum desulfurization efficiency was 99.09% for dibenzothiophene (DBT) and 97.94% for thiophene using a solvent to feed ratio of 1:1 and applying a stirring time of 60 minutes. The quality of the model diesel has been checked with respect to flash point, aniline point, diesel index, and cetane index both pre- and post-desulfurization.

Desulfurization of model diesel by extraction/oxidation using a zinc-substituted polyoxometalate as catalyst under homogeneous and heterogeneous (MIL-101(Cr) encapsulated) conditions

A composite material comprising the chromium terephthalate metal-organic framework MIL-101 and the tetrabutylammonium (TBA) salt of a zinc-substituted polyoxotungstate anion, TBA4.2H0.8[PW11Zn(H2O)O39] (denoted PW11Zn), has been prepared by an impregnation method and characterized by powder X-ray diffraction, scanning electron microscopy, N2 adsorption/desorption, thermogravimetric analysis, FT-IR, FT-Raman and 31P magic-angle spinning (MAS) NMR spectroscopies. The characterization data reveal that the polyoxometalate was homogeneously encapsulated within the cages of the support without affecting its crystalline structure and morphology. Both the homogeneous catalyst PW11Zn and the composite material PW11Zn@MIL-101 exhibit high activity in the extractive and catalytic oxidative desulfurization of a model oil containing dibenzothiophene, 1-benzothiophene and 4,6-dimethyldibenzothiophene. Complete desulfurization of the model oil could be achieved within 2 h by using the ionic liquid (IL) 1-butyl-3-methylimidazolium hexafluorophosphate as extraction solvent, aqueous 30% H2O2 as oxidant and a reaction temperature of 50°C. When acetonitrile was used as extraction solvent instead of the IL, the heterogeneous catalyst PW11Zn@MIL-101 could be easily recovered and reused several times without leaching or loss of activity.

Hydrogen peroxide oxidative desulfurization of model diesel mixtures using azacrown ethers

Hydrogen peroxide oxidative desulfurization of model diesel fuel mixtures in the presence of azacrown ethers and their complexes with niobium pentachloride at 40–80°C has been studied. It has been found that the use of complexes of azacrown ethers with NbCl5 leads to a decrease in the total sulfur content in the model mixtures to 13% of the initial amount. The structure of the azacrown ether used has little effect on the extent of desulfurization of the model mixture.

Hydrogen peroxide oxidative desulfurization of model diesel fuel mixtures in the presence of crown ethers and transition metal peroxo complexes

The catalytic ability of crown ethers and their complexes with transition metal cations in the desulfurization reaction of mixtures that simulate diesel fuel has been investigated. It has been found that the use of monoaza-15-crown-5-ethers with an admixture of NbCl5 resulted in a fourfold decrease of the total sulfur content, thereby indicating partial oxidation of benzothiophenes and dibenzothiophenes. The complexation of azacrown ethers with NbCl5 has been studied by 1H NMR spectroscopy. A moderate efficiency of adsorption purification procedure using silica and alumina for both initial and oxidized model mixtures has been revealed.