Deep Desulfurization Of Fuels Research Articles

Oxidative desulfurization of fuels using alcohol-based DESs.

The presence of sulfur-containing compounds in fuel oil has become a major global issue due to their release of toxic sulfur dioxide. Hydrodesulfurization is a commonly used method for removing sulfur from fuel. However, new desulfurization techniques have been developed recently as hydrodesulfurization (HDS) is ineffective in removing refractory sulfur, e.g., BT, DBT, 4-MDBT. In this study, a series of deep eutectic solvent (DES) using ChCl, salicylic acid, oxalic acid, citric acid, and adipic acid as hydrogen bond acceptors and MeOH, EtOH, BuOH, EG, DEG, and TEG as hydrogen bond donors on different mole ratios were synthesized and then investigated the efficiency of these DESs in extracting sulfur from model and diesel fuel. Densities, viscosity, refractive index, and FTIR spectra of synthesized DESs were recorded. It also included oxidative desulfurization, which is a promising approach offering high selectivity, mild reaction conditions, low cost, and high efficiency. Hydrogen peroxide was selected as the oxidant in this study due to its excellent performance, commercial availability, and high proportion of active oxygen. [Citric acid: TEG] [1:7] and [adipic acid: TEG] [1:8] were found to be the most effective, removing up to 44.07% and 42.53% sulfur from model oil during single-stage extraction at 30°C using a solvent-to-feed ratio of 1.0 and was increased to 86.87% and 85.06% using successive extraction up to the fourth stage. On oxidation, extraction efficiencies were reported to be 98.98%, 87.79%, and 56.25% and 96.96%, 81.22%, and 44.51% for model oil containing DBT and diesel 1 and diesel 2 with DES [citric acid: TEG] [1:7] and [adipic acid: TEG] [1:8] respectively at 30°C using a solvent-to-feed ratio of 1.0. The study found that [citric acid: TEG] [1:7] exhibits better extraction performance in the deep desulfurization of fuels at an extraction temperature of 30°C.

Preparation of formate-free PMA@MOF-808 catalysts for deep oxidative desulfurization of model fuels.

Due to the increasingly serious environmental problems caused by the combustion of sulfides in fuel, deep desulfurization of fuel became particularly urgent. Herein, the catalyst (PMA@MOF-808) of the Zr-based metal-organic framework (MOF-808) encapsulating phosphomolybdic acid (PMA) was prepared via a one-pot hydrothermal method. Besides, the formate ions of PMA@MOF-808 were removed by posttreatment with methanol, resulting in formate-free PMA@MOF-808-H catalysts with unsaturated open metal sites. The as-synthesized catalysts were systematically characterized by XRD, FT-IR, SEM, BET, TGA, 1H NMRand XPS. The catalysts were also applied in catalytic oxidation desulfurization of fuel. The results indicated that the introduction of PMA and the removal of formate ions can improve the desulfurization performance of catalysts. Formate-free 0.2-PMA@MOF-808-H catalyst can reach 100% desulfurization rate for DBT. Besides, the kinetic properties were studied, and the apparent activation energy was 29.34kJ/mol.

Deep desulfurization of fuels: Are deep eutectic solvents the alternative for ionic liquids?

The impact of fossil fuels impurities on outdoor air pollution is today a matter of great concern, with the transportation sector playing a major role. Given global efforts to reduce sulfur oxides emissions, and the increasingly tighter legislations, removal of sulfur contaminants liquid highway fuels is a pressing issue worldwide. The purpose of this review is to provide a detailed state of the art review concerning the use of deep eutectic solvents (DES) in the removal of sulfur pollutants from transportation fuels. Furthermore, a comparative evaluation regarding the use of these solvents versus Ionic Liquids (ILs) is also provided, taking into account several aspects, such as, evolution of technologies, solvents composition, extraction efficiencies and environmental and economic considerations. The large gap in terms of efficiency of the reported technologies, either using ILs or DES, between simulated matrices and real fuels is also discussed, highlighting the importance of academia and industry hand in hand work.

Ultrafast Oxidative Desulfurization of Diesel Fuels by Mass Transfer Enhancement of Polyoxometalate Modified Alumina Catalysts

Deep desulfurization of fuels has long been and remains to be a highly challenging issue. In this work, a trilacunary polyoxometalate of Na12[α-P2W15O56]·24H2O (P2W15) was covalently tethered onto ...

Deep desulfurization of fuels using supported ionic liquid-polyoxometalate hybrid as catalyst: A comparison of different types of ionic liquids

In this work, polyoxometalates-based monomer ionic liquid, dimer ionic liquid and polyionic liquid were designed and prepared. Then supported catalysts were synthesized by loading polyoxometalate derivatives on the surface of graphene oxide (GO). The catalysts before and after loading were characterized via many tests such as scanning electron microscope (SEM), infrared spectroscopy (IR), X-ray powder diffraction (XRD) and so on. The influences of ionic liquid type and carrier on desulfurization activity were carried out. The result shows that supported catalyst-based polyionic liquid (P[Vim]POM/GO) performed high activity and excellent recyclability in extraction-oxidation desulfurization (EODS) due to unique state of polyoxometalate and the support of graphene oxide. In addition, the possible mechanism of oxidation dibenzothiophene (DBT) with H2O2 was proposed according to the kinetic study and gas chromatography-mass spectrometer (GC–MS) result.

Preparation of Efficient TS‐1 with Small Particle Size and Enhanced Framework Ti

AbstractCrystal size and framework Ti content are two main factors which influence catalytic performances of TS‐1 catalysts. Control over the crystal size and framework Ti of TS‐1 through the synthesis of TS‐1 in the presence of polyethylene glycol (PEG) is reported. The crystal size of TS‐1 sample synthesized in the presence of PEG, TS‐1‐PEG was 230 nm. However, the size of TS‐1 synthesized without PEG, standard sample, was 290 nm. The TS‐1‐PEG possess higher amount of framework Ti content and less anatase TiO2 in comparison with TS‐1. The catalytic reaction tests showed superior activity of TS‐1‐PEG toward hydroxylation of phenol and oxidation of dibenzothiophene, deep desulfurization of fuels, as a result of cooperative effects of smaller particle size and higher framework Ti content. Consequently, using safe and un‐expensive PEG polymer is a powerful approach to synthesize TS‐1 with small crystal size and high framework Ti content to make efficient TS‐1 catalyst.

Magnetically responsive porous materials for efficient adsorption and desorption processes

Abstract Magnetically responsive porous materials possess unique properties in adsorption processes such as magnetic-induced separation and heat generation in alternating magnetic fields, which greatly facilitates recycling procedures, favors long-term operation, and improves desorption rate, making conventional adsorption processes highly efficient. With increasing interest in magnetic adsorbents, great progress has been made in designing and understanding of magnetically responsive porous materials varying from monoliths to nanoscale particles used for adsorption including oil uptake, removal of hazardous substances from water, deep desulfurization of fuels, and CO2 capture in the past few years. Therefore, a review summarizing the advanced strategies of synthesizing these magnetically responsive adsorbents and the utilization of their magnetism in practical applications is highly desired. In this review, we give a comprehensive overview of this emerging field, highlighting the strategies of exquisitely incorporating magnetism to porous materials and subtly exploiting their magnetic responsiveness. Further innovations for fabricating or utilizing magnetic adsorbents are expected to be fueled. The potential opportunities and challenges are also discussed.

Extractive Desulfurization of Model Oil with Protic Ionic Liquids

Deep desulfurization of fuels has attracted worldwide attention as a result of environmental concerns. In this study, a new series of protic ionic liquids (PILs) with different acidic anions were s...

Interfacial behaviour of substituted dibenzothiophenes for their extraction in biphasic dodecane-ionic liquid systems

Deep desulfurization of fuels by using ionic liquids (ILs) has gained notable attention and has been a subject of concern. This study aims at the extraction tendencies of two alkylated derivatives of an aromatic sulfur compound, 4-Methyldibenzothiophene (MDBT) and 4,6-Dimethyldibenzothiophene (DMDBT) from oil using four ILs namely, Ethylmethylimidazolium tetrafluoroborate [EMIM][TFB], Butylmethylimidazolium tetrafluoroborate [BMIM][TFB], Ethylmethylimidazolium thiocyanate [EMIM][SCN], Butylmethylimidazolium thiocyanate [BMIM][SCN] via molecular dynamics simulation. A interfacial phenomena of extraction pathway of MDBT and DMDBT in biphasic system of dodecane and ILs was studied at molecular level. The transfer of sulfur compounds during the extraction processes, were observed to be controlled by type of IL as well as sulfur compound and interfacial resistance. This study will also help in selecting an appropriate IL as an extractant and improving the process conditions.

Using response surface methodology to optimize ultrasound-assisted oxidative desulfurization

Latest strict environmental regulations have restricted the sulfur content of diesel fuels; therefore, deep desulfurization of fuels is required. Ultrasound-assisted oxidative desulfurization (UAOD) is an alternative for conventional desulfurization methods which can remove sulfur compounds from fuels under mild process conditions. In this study, UAOD of gasoil using tungstophosphoric acid catalyst and tetraoctylammonium bromide as a phase transfer agent in the presence of hydrogen peroxide as an oxidant was optimized. The optimal design of experiments was generated based on central composite face-centered design of Response surface methodology (RSM) to study effects of four process variables such as oxidant volume, mass of catalyst, mass of phase transfer agent and the ultrasonic wave amplitude on the sulfur conversion of gasoil. In addition, a predictive model of sulfur conversion was obtained based on RSM. The optimal values of process variables were evaluated to be 21.96 mL of oxidant, 1 gr of catalyst and 0.1 gr of phase transfer agent to achieve the maximum sulfur conversion of 95.92%.

Ultrasound assisted oxidative desulfurization of model diesel fuel

Very stringent environmental regulations have limited the level of sulfur in diesel, therefore deep desulfurization of fuels is required. For that purpose, the frequently used industrial process is hydrodesulfurization (HDS) which enables effective elimination of sulfur compounds such as mercaptanes, thiols, sulfides, disulfides from diesel oil, but removal of thiophene sulfur compounds (benzothiophene, dibenzothiophene, 4,6 dimethyldibenzothiophene) is insufficient. Ultrasound assisted oxidative desulfurization (UAOD) as one of several new technologies enables performance under mild conditions without use of explosive hydrogen. A higher reactivity of thiophene sulfur compounds during UAOD also provides conversion into highly polar sulfoxides and sulfones that are easily removed by adsorption or extraction. Nowadays, different catalyst/oxidants systems are being studied to improve oxidation reaction efficiency and enhance the mass transfer in the interfacial region. In this paper, the effect of reaction temperature (40–70°C) and oxidation time (5–150min) for UAOD of model diesel fuel with a catalyst/oxidants system (acetic acid/hydrogen peroxide) was investigated in a 70ml batch reactor. Furthermore, the effects of different initial concentrations of dibenzothiophene (DBT) and of ultrasound amplitude were additionally examined to achieve efficient sulfur removal. The obtained results indicated that temperature and US amplitude of 70°C and 80% respectively were efficient for conversion of DBT (sulfur concentration up to 3976.86ppm). The results indicate a rise in the yield of sulfones at higher temperatures and subsequent extraction with N,N-dimethylformamide conducted after the process of oxidation at different solvent/oil ratio revealed sulfur removal efficiency of 98.35%.

Oxidative Desulfurization of Fuels using 1-Butyl-6-Methyl-Quinolinium Dicyanamide

Deep desulfurization of fuels has attracted a lot of attention from researchers due to more stringent regulations imposed on sulfur content. There is a great demand to comply the regulation in current technology because it requires high pressure, high temperature, and high hydrogen consumption. Furthermore, aromatic sulfur compounds are also inefficient to be removed in current technology. Ionic Liquids (ILs), a class of green solvent plays an important role as a promising alternative for desulfurization of fuels. This study investigates the potential of oxidative desulfurization through liquid-liquid extraction process and the effect of parameter variation towards the efficiency.

Deep Desulfurization of Fuels by Extraction with 4-Dimethylaminopyridinium-Based Ionic Liquids

In this work, three 4-dimethylaminopyridinium-based ionic liquids (ILs), N-ethyl-4-dimethylaminopyridinium dicyanamide ([C24DMAPy][N(CN)2]), N-butyl-4-dimethylaminopyridinium dicyanamide ([C44DMAPy][N(CN)2]) and N-hexyl-4-dimethylaminopyridinium dicyanamide ([C64DMAPy][N(CN)2]), were synthesized and then demonstrated to be efficient for aromatic sulfur compounds extraction from fuels. The mutual solubility evaluating results indicated that 4-dimethylaminopyridinium-based ILs hardly dissolved in the fuels, while the solubility of 97# gasoline in ILs varies from 7.0 wt % for [C24DMAPy][N(CN)2] to 12.4 wt % for [C64DMAPy][N(CN)2] and the solubility of 0# diesel in ILs varies from 6.7 wt % for [C24DMAPy][N(CN)2] to 9.7 wt % for [C64DMAPy][N(CN)2]. Also, the sulfur partition coefficient was evaluated. In the case of model gasoline, the thiophene (TS) partition coefficient in model gasoline varies from 0.885 for [C24DMAPy][N(CN)2] to 1.218 for [C64DMAPy][N(CN)2]. In the case of model diesel, 4-dimethylaminopyridinium-based ILs exhibit a relatively higher sulfur partition coefficient, compared to alkyl modified pyridinium-based ILs. 1H NMR results confirmed that the high aromatic π-electron density of the dimethylaminopyridinium cation was the main reason for the good extraction performance. 1H NMR results also confirmed the KN sequence for each IL ([C24DMAPy][N(CN)2] < [C44DMAPy][N(CN)2] < [C64DMAPy][N(CN)2]) is mainly due to the sulfur compounds and ILs structures. Furthermore, the extractive selectivity results indicated a more preferable extraction of TS than toluene with 4-dimethylaminopyridinium-based ILs. To have a better evaluation of the overall sulfur extraction performance, the three 4-dimethylaminopyridinium-based ILs were compared to other typical ILs (e.g., pyridinium-based ILs and imidazolium-based ILs), which suggested our synthesized 4-dimethylaminopyridinium-based ILs exhibited good balance between mutual solubility and the sulfur partition coefficient. ILs after use were regenerated by a water dilution process. Based on these results, 4-dimethylaminopyridinium-based ILs can be used as potential extractants for EDS processes.

Deep Desulfurization of Fuels by Heteropolyanion-Based Ionic Liquid

A new heteropolyanion-based ionic (<TEX>$[Hmim]_5PMo_{10}V_2O_{40}$</TEX>) was synthesized by the reaction of molybdovanadophosphoric acid (<TEX>$H_5PMo_{10}O_{40}$</TEX>) with N-methylimidazole. [<TEX>$[Hmim]_5PMo_{10}V_2O_{40}$</TEX> showed a high catalytic activity in the oxidative desulfurization of sulfur-containing compounds in 1-methylimidazolium tetrafluoroborate (<TEX>$[Hmim]BF_4$</TEX>) ionic liquid using 30% aqueous <TEX>$H_2O_2$</TEX> as the oxidant. The catalytic system was of high activity, simplified workup and flexible recyclability. The catalytic oxidation reactivity of sulfur-containing compounds decreased in the order dibenzothiophene (DBT) > 4,6-dimethyldibenzothiophene (4,6-DMDBT) > benzothiophene (BT). The influences of various parameters including reaction time (t) and temperature (T), catalyst dosage, and oxidant to sulfur molar ratio n(O)/n(S) on the desulfurization of model oil were investigated in details. 99.1% of DBT conversion in the model oil was achieved at atmospheric pressure under the optimal conditions: n(O)/n(S) = 4:1, <TEX>$60^{\circ}C$</TEX>, 100 min and molar ratio of catalyst to sulfur of 0.062. The ionic liquid can be recycled six times without significant decrease in activity.

Deep Fuels Desulfurization and Denitrogenation Using 1-Butyl-3-methylimidazolium Trifluoromethanesulfonate

The aim of this study is to investigate the possible use of 1-butyl-3-methylimidazolium trifluoromethanesulfonate ([BMIM][OTf]) as solvent for three separation tasks which appear in deep desulfurization of fuels: {aromatic sulfur compound + aliphatic hydrocarbon}, {nitrogen compound + aliphatic hydrocarbon}, or {sulfur compound + aliphatic hydrocarbon}. New three ternary systems are studied to investigate the capacity and selectivity of [BMIM][OTf] for extraction of sulfur and nitrogen containing aromatic organic compounds from aliphatic hydrocarbons. Aromatic hydrocarbon capture, which often appears causing unwanted reduction of fuel octane number, is also investigated. Therefore, LLE measurements of ternary mixtures for three systems are presented: {thiophene + n-heptane + [BMIM][OTf]}, {pyridine + n-heptane + [BMIM][OTf]}, {benzene + n-heptane + [BMIM][OTf]}, and {thiophene + n-heptane + [BMIM][OTf]} at 298.15 K and atmospheric pressure. The liquid−liquid equilibrium (LLE) data are correlated by the use of the NRTL model. Moreover, the extraction experiments of synthetic fuels—model gasoline and model diesel using [BMIM][OTf]—have been performed. The influence of three stepped extraction procedure using each time a fresh portion of [BMIM][OTf] on the final gasoline and diesel compositions is presented.