Model Diesel Oil Research Articles

Получение экологичного катализатора на основе четвертичной аммониевой соли гетерополикислоты для глубокой окислительной десульфуризации дизельного топлива

Hydrodesulfurization (HDS) is the most widely used method for fuel oil desulfurization, which can easily remove mercaptan and thiophene from diesel oil, but the removal rate of dibenzothiophene (DBT) and its alkylated derivatives is low. Compared with traditional HDS technology, oxidative desulfurization (ODS) technology has the advantages of less investment, mild reaction conditions, and high ODS activity for DBT and its derivatives. Heteropoly acid (salt)/H2O2 system is highly efficient and the oxidation product of hydrogen peroxide is water, making them green catalysts. A new type of polyoxometalates phase transfer catalyst, [(C16H33(CH3)3)N]3-HPW11VO40, was synthesized through ion exchange method. It was applied to the catalytic oxidative desulfurization of model diesel oil using H2O2 as oxidant. The influencing factors of reaction were investigated in detail. The catalyst exhibits the dibenzothiophene conversion rate of 100% and excellent reusability and retrievability with 99.97% conversion after five times reaction in mild reaction conditions of n(catalyst)/n(DBT)=1/80, n(H2O2)/n(DBT)=8/1, 50 °C, and atmospheric pressure in 3 h. The catalyst could be quickly separated and recycled by centrifugation after reaction and hence be promising in the low-sulfur fuel production.

Two-Stage Sequential Adsorption System for Denitrogenation and Desulfurization of Model Diesel Oil over Ion-Exchanged Y Zeolites

This work focused on adsorptive desulfurization (ADS) and denitrogenation (ADN) in single- and two-stage systems. Na-Y zeolite possessed the best 4,6-DMDBT and DBT adsorption performances. La-Y zeolite exhibited the best ADN efficiency. The impact of nitrogen compounds and aromatics on ADS capacity and the impact of sulfur compounds and aromatics on ADN ability over ion-exchanged Y zeolite were evaluated in the single-stage system. The nitrogen compounds not only have the ability to compete, but they also have a higher absorbability than sulfur compounds. The sequential adsorption in a two-stage system was proposed to enhance ADS ability. The first stage contained La-Y for ADN, and the second stage contained Na-Y for ADS. It was found to successfully increase the breakthrough capacity of all compounds by 40% compared with the single-stage system. This two-stage sequential system is a suitable route for the elimination of sulfur and nitrogen content in diesel oil.

Hybrid Nanoarchitectonics with Cr, Fe-MOF/ Graphene Nanocomposite for Removal of Organic Sulfur Compounds from Diesel Fuel

Metal–organic frameworks (Cr-MOF and Fe-MOF) and their graphene hybride nano-composites were prepared via green solvo-themal method. The prepared samples were characterized by XRD, FTIR spectroscopy, N2 adsorption–desorption isotherm and XPS. The composites were used for the adsorption of thiophenic sulfur compound (thiophene, dibenzothiophene, 4,6-dimethyldibenzothiophene) in a model fuel oil. It was found that, graphene in the MOF composite has positive effect on sulfur removal. The removal efficiency increase from 62% to % 95.6 using Fe-MOF and Fe-MOF/Gr (9:1), respectively. This enhancement effect is attributed to a greater number of coordinatively unsaturated sites (CUS) in the composites. The results indicated that the adsorption reach to 96.6% for DBT adsorption from model diesel oil and 62% for diesel fuel on using Cr-MOF/Gr composite.

Synthesis and characterization of iron-alumina composites as novel efficient photocatalysts for removal of DBT

The content of sulfur compounds in diesel fuels is one of the main encountered drawbacks during the production process. Such compounds are generally of substantial, hazardous, and negative environmental impacts. Thus, the massive reduction of their content is recommended. Among these compounds, DBT is one of the most challenging compounds to be disposed of industrially via the HDS method. Therefore, this study presents the removal of such compounds using the oxidative-photocatalytic desulfurization technique. Three iron oxide doped alumina composites containing different weight percentages of iron (10–30%) were synthesized as novel photocatalysts. Structural characteristics of these composites were verified via X-ray diffraction (XRD) by detecting the indicative peaks for Fe2O3 and Al2O3. These composites' surface and optical properties could reveal their mesoporous nature and suitability as effective visible-light photocatalysts. These structures were next introduced to the process of DBT removal from a model diesel oil with a content of 1500 ppm at different operating conditions. The composite, which contains 20% iron oxide, was the most effective photocatalyst of DBT elimination. Specifically, 97% removal of sulfur content in the model diesel oil was successfully attained under visible-light irradiation source with a power of 500 W at a reaction time equals to 30 min, 1 g/L as photocatalyst dose and H2O2 to feed ratio of 1.5.

Aerobic ultra-deep desulfurization of diesel oil triggered by porous carbon supported organic molecular N-hydroxyphthalimide catalyst

Molecular oxygen is an ideal oxidant in various reaction because it is cheap, easily available, and environmentally friendly. However, it is hard to be activated under atmosphere condition within a short reaction time. In this study, the organic molecular catalyst N-hydroxyphthalimide (NHPI) was loaded on the surface of petroleum coke-based porous carbon (PC) via impregnation. Using cobalt acetate as a co-catalyst, the resulting NHPI/PC are demonstrated to be highly efficient and recyclable catalysts for aerobic oxidative desulfurization of model diesel oil. Under the optimal reaction conditions, the conversion rate of dibenzothiophene in the model oil could reach 100.0% in only 3 h. In addition, 4-methyldibenzothiophene and 4, 6-dimethyldibenzothiophene with greater steric hindrance can still reach 99.2% and 97.2% within 4 h. Due to the great adsorption of the catalyst to oxidative product, the sulfur content could decrease to 7 mg kg−1. In the free radical trapping experiment, superoxide radicals were detected by electron spin resonance. After adding p-benzoquinone, the conversion rate of DBT decreased from 100.0% to 3.0%, which further verified that superoxide free radical was the main active species. Reusability tests proved that the catalyst still had strong catalytic activity even after 9 cycles and might possess a good prospect of industrialization. In addition, the sulfur content in actual diesel oil could be decreased from 852 mg kg−1 to 91 mg kg−1, which further indicated that the catalyst had a good prospect of industrial application.

Adsorption of diesel oil onto natural mud shale: from experimental investigation to thermodynamic and kinetic modelling

ABSTRACT A natural mud shale (MS) from Yichang Area, China was for the first time experimentally examined for its potential application to oily effluents treatment. The mineralogical compositions, surface structures and pore size distribution of the prepared MS particles were characterised using various advanced analytical technologies, respectively. The performance of the MS particles during the model diesel oil wastewater treatment was examined based on the designed adsorption experiments. Isothermal and kinetic features were investigated according to a variety of adsorption models. The results showed that some pores, cavities and fractures were distributed on the surface of MS particles. The efficiency of MS particles for removing diesel oil from the model oily effluent was associated closely with experimental conditions including the mass of MS particles, initial diesel levels, residence time and pH values. Equilibrium adsorption isotherms conformed to Langmuir model, indicating that the adsorption of diesel oil onto MS particles tended to monolayer adsorption. Kinetics of adsorption of diesel oil on MS complied with the pseudo-second-order model. This suggested that the whole oil removal rate was mainly controlled by chemisorption. Results of our study indicates potential utilisation of unmodified MS particles as an abundant and inexpensive adsorbent for low-concentration diesel oil wastewater.

Creation of Active Sites in MOF‐808(Zr) by a Facile Route for Oxidative Desulfurization of Model Diesel Oil

AbstractMOF‐808(Zr) as an important member of metal‐organic frameworks (MOFs) has attracted much attention due to its good stability, large surface area and rich zirconium metal centers. However, Zr sites in the structure of MOF‐808(Zr) are inactive in many catalytic reactions due to they are well coordinated with organic ligands like 1,3,5‐benzenetricarboxylic acid (BTC) and formate anions. Thus, removing formate anions have been attempted to create more active sites in the structure for many reactions while maintaining the structural stability. In this work, we report that the formate ligands in MOF‐808(Zr) can be facilely removed by the treatment in hot ethanol for 4 h. The obtained material as a heterogeneous catalyst exhibited superior catalytic activity in the oxidative desulfurization (ODS) reaction of dibenzothiophene (DBT) compared with reported MOFs catalysts. The conversion of DBT in model diesel oil could reach >99 % within a reaction time of 20 min at 323 K, which is five times as that over parent MOF‐808(Zr). As a result, the sulfur content was decreased from 1000 ppm to less than 10 ppm. Such catalytic performance should be mainly attributed to the creation of more active sites in the structure of MOF‐808(Zr) after the removal of formate anions.

Oxidative desulfurization of benzothiophene derivatives with cis-dioxomolybdenum(VI) catalyst precursors, under extractive conditions

The study of the activity of a series of heterogeneous cis-dioxomolybdenum(VI) based catalyst precursors for the hydrogen peroxide promoted oxidation of benzothiophene, 2- and 3-methylbenzothiophene, dibenzothiophene and 4,6-dimethyldibenzothiophene, has been carried out. The last, chosen as model substrates of the common sulfurated derivatives of fuels, have been oxidized in the presence of selected imidazolium based ionic liquids, under extractive oxidative desulfurization conditions. The reactivity of sulfur-containing compounds toward the oxidation to their corresponding sulfones has been evaluated, firstly, for each type of substrate alone, and then applying the optimized procedure to a system formed by all sulfurated substrates. Our aim was to mimic the oxidation of a model diesel oil, under either thermal or microwave assisted heating. Cis-dioxomolybdenum (VI) compounds behaved as very active and stable catalytic systems retaining, in one selected case, the original activity at least for three cycles. Imidazolium ionic liquids played a dual fundamental role not only as extractant and reaction medium but also as stabilizing system for both the oxidant and the catalytic agents. Under optimized microwave-assisted conditions, the quantitative elimination of sulfurated substrates from the model diesel oil, was obtained after only 1 h or 2 h, when [BMIM]OTf or [BMIM]BF4 and [OMIM]BF4, respectively, have been used as ionic liquids.

Regenerable CuO/γ-Al2O3-Reduced Graphene Oxide Adsorbent with a High Adsorption Capacity for Dibenzothiophene from Model Diesel Oil

This research focused on the removal of dibenzothiophene (DBT) from model diesel oil using CuO-loaded γ-Al2O3–reduced graphene oxide (CuO/γ-Al2O3–RGO) as an adsorbent, which possesses the highest a...

Oxidative Desulfurization of Diesel Using Vanadium-Substituted Dawson-Type Emulsion Catalysts

In this study, we aimed at investigating the catalytic oxidative desulfurization (CODS) of the model diesel oil and real diesel oil using the vanadium-substituted Dawson-type emulsion catalyst ([cetrimonium]6+xP2W18–xVxO62 (x = 1, 3, 5)). Among all prepared samples, [cetrimonium]11P2W13V5O64 showed the best results in CODS of model diesel oil under determined conditions (10 g/L catalyst and O/S mole ratio = 4). The Taguchi method was then applied to optimize the catalyst dosage, hydrogen peroxide dosage, and the reaction temperature in CODS using the best emulsion catalyst. Then formic acid and acetic acid were used as a co-oxidant to improve the oxidation ability. Under optimum conditions, a mixture of H2O2/formic acid (1:1), in the presence of [cetrimonium]11P2W13V5O62 could remove 98% of dibenzothiophene and 82% of benzothiophene. Finally, under optimum conditions of CODS, 90% of total sulfur was removed from a real diesel sample. It is worth mentioning that we could recycle [cetrimonium]11P2W13V5O64, ...

Removal of thiophene from model diesel oil with nitrate based ionic liquids at several temperatures

In this work the desulfurization ability of two imidazolium based ionic liquids from n-decane, which is used as a model of fuel, has been developed. The systems of ternary liquid-liquid equilibria containing ionic liquid+n-decane+thiophene have been determined at three different temperatures. All systems have been shown the ability of ILs for removal of thiophene from n-decane. The selectivity and the solute distribution ratio were calculated for all systems. The data obtained have been correlated with non-random two liquid NRTL model. The phase equilibria diagrams for the ternary mixtures including the experimental and calculated tie-lines have been presented.

Evaluation of the biological methane potential of various feedstock for the production of biogas to supply agricultural tractors

This work is divided into three parts. The first one presents results of biological methane potential of agriculture raw materials available in Poland. In the second part the simple mathematical model of methanogenic fermentation is proposed. The data for this model were obtained from experimental digestion process of chosen mixtures. Last part includes the results of research of exhaust emissions generated by dual dual-fuel engine of agricultural tractor powered by mixture of model biogas (60% and 70% of methane) and diesel oil. The obtained results revealed that there was a significant difference in chemical composition and yield of biogas between considered feedstock types. The highest biogas and methane production was obtained for mixtures in ratio of 6:4 for swine manure/maize silage and whey/grass silage. Due to agriculture conditions in Poland and obtain results, the maize silage and swine manure were chosen to development of mathematical model of fermentation process. It showed a satisfactory match to the experimental results.Results of emission tests on dual-fuel tractor engine supplied with biogas and diesel oil showed the higher concentrations of hydrocarbons and carbon oxide and lower concentrations of particulate matter in exhaust gases. Level of emission of particular components depends on the biogas composition.

Adsorptive desulphurization study of liquid fuels using Tin (Sn) impregnated activated charcoal

Keeping in view the growing concern regarding desulphurization of petroleum products, the present study was under taken to investigate the efficiency of tin impregnated activated charcoal (Sn–AC) as a potential adsorbent for the desulphurization of model and real commercial straight run kerosene and diesel oil samples. The adsorbent Sn–AC was prepared by wet impregnation process in the laboratory and characterized by SEM, EDX and surface area analysis. Initial experiments were carried out using model oil, which was prepared by dissolving dibenzothiophene (DBT) in cyclohexane, the optimum conditions for desulfurization were found to be, 60°C temperature, 1h contact time and adsorbent dosage of 0.8g, under which about 99.4% of DBT removal was attained. Under optimized conditions the desulfurization of real oil i.e., kerosene and diesel oil was also investigated. Kinetic studies revealed that DBT adsorption followed pseudo second order kinetics and the data best fits in the Langmuir adsorption isotherm as compared to Freundlich adsorption isotherm model. The adsorbent could be easily regenerated simply by washing with toluene for a multiple cycles and reused without losing its efficiency.

Deep oxidative/adsorptive desulfurization of model diesel oil by DBD/FeCl3–SiO2

Oxidative/adsorptive desulfurization of model diesel oil by a dielectric barrier discharge (DBD) plasma in the presence of air as oxygen resource was studied. This new system exhibited excellent desulfurization effect at room temperature when FeCl3–SiO2 is used as catalyst and adsorbent. The sulfur content of DBT in model oil can be decreased from 200ppm to 3ppm (S-removal rate up to 98.4%) under optimum reaction conditions (air flow rate (υ), 90ml/min; amplitude of applied voltage (U) on DBD, 30kV; input frequency (f), 600Hz; catalyst amount (ω), 3wt%; the reaction time (t), 30min). It is obvious that the DBD/FeCl3–SiO2 had better desulfurization ability than the DBD, FeCl3, and SiO2 were used alone. Moreover, the good desulfurization rate of BT (benzothiophene) and 4,6-DMDBT (4,6-dimethyl-dibenzothiophene) could reach 94.8% and 92.7% under the above conditions, and the sulfur removal selectivity for S-compounds followed the order of DBT>BT>4,6-DMDBT.

Nickel supported on zinc oxide nanowires as advanced hydrodesulfurization catalysts

A novel catalyst with deep hydrodesulfurization (HDS) capabilities was tested with the aim of producing ultra-low sulfur diesel oil. The catalyst consisted of a zinc oxide nanowire (ZnO NW)/alumina carrier impregnated with nickel (Ni) as the active phase. Based on the concept of reactive adsorption, it was hypothesized that enhanced metal–support interactions and short diffusion paths between Ni and ZnO NWs could lead to improved activity and sulfur uptake capacity. Long ZnO NWs (10–15μm) were produced in bulk quantities using an atmospheric plasma jet reactor. In situ heating studies of Ni impregnated ZnO NW samples revealed better Ni dispersion, greater Ni-support interaction, and smaller Ni particle sizes when compared to a support comprised spherical ZnO nanoparticles (NPs). The reactive adsorbent was tested for on-stream sulfur uptake with model diesel oil spiked with difficult-to-remove organic sulfur species. The data indicated high activity for deep de-sulfurization in the initial stages but the catalyst deactivated via coking after 16h. The coking appears to be due to cracking of aromatic species present in the model oil in the absence of adsorbed surface hydrogen. The initial activity of the catalyst with modest composition of nickel loading indicated the potential utility of the catalyst system involving ZnO NWs as support.

Liquid−Liquid Equilibria for {1-Ethyl-3-methylimidazolium Diethylphosphate or 1-Ethyl-3-methylimidazolium Ethylsulfate} + 4,6-Dimethyldibenzothiophene + Dodecane Systems at 298.2 K and 313.2 K

Liquid−liquid equilibrium (LLE) data for {1-ethyl-3-methylimidazolium diethylphosphate ([emim][DEtPO4]) or 1-ethyl-3-methylimidazolium ethylsulfate ([emim][EtSO4])} + 4,6-dimethyl-dibenzothiophene (4,6-DMDBT) + dodecane systems, at (298.2 and 313.2) K and atmospheric pressure (≈ 95 kPa), were determined by refractometry. 4,6-DMDBT is one of the most difficult diesel sulfur pollutants to remove by the conventional process of hydrodesulfurization (HDS). Extraction of 4,6-DMDBT from dodecane (used as model diesel oil) was analyzed in terms of solute distribution coefficient, solvent selectivity, and percent of extraction. The results indicate that [emim][DEtPO4] is a better solvent for extractive desulfurization of dodecane than [emim][EtSO4]. The Hand and Othmer−Tobias correlations, used to ascertain the quality of the experimental data, presented R2 > 0.98 for systems with [emim][DEtPO4] and R2 > 0.96 for systems with [emim][EtSO4]. The nonrandom two-liquid (NRTL) model was used to correlate the LLE data a...

Effect of surfactant modification on the desulfurization performance of Zn/Ti-PILCs adsorbent

Various surfactants were added during the synthesis of pillared clays Ti-PILCs to modify their structure and properties. Zn supported on the surfactant-modified Ti-PILCs (Zn/Ti-PILCs) was used as a desulfurization adsorbent and its performance in desulfurization of a model diesel oil containing dibenzothiophene (DBT) was investigated. The results showed that the capability of Zn/Ti-PILCs for DBT selective adsorption is enhanced by the surfactant modification. Especially, Zn/Ti-PILCs-CTAB obtained through modification with hexadecyl-trimethyl-ammonium bromide (CTAB) (CTAB/Ti molar ratio being 0.5) exhibits high desulfurization performance with a DBT removal rate of 96.3%. The characterization results of nitrogen sorption indicated that the surfactants added during the pillaring process can increase the surface area of the resultant Ti-PILCs and improve their pore distribution by enhancing the amounts of mesopores (1–4 nm).

Liquid−Liquid Equilibrium Data in Ionic Liquid + 4-Methyldibenzothiophene + n-Dodecane Systems

In this work, liquid−liquid equilibrium data for 1-ethyl-3-methylimidazolium diethylphosphate ([emim][DEtPO4]) or 1-ethyl-3-methylimidazolium ethylsulfate ([emim][EtSO4]) + 4-methyl-dibenzothiophene (4-MDBT) + n-dodecane systems at 25 and 40 °C and atmospheric pressure (≈95 kPa) were determined by refractometry. 4-MDBT is a DBT derivative and it is one of the most difficult diesel sulfur pollutants to remove by the conventional process of hydrodesulfurization. The liquid−liquid equilibrium data were used to study the 4-MDBT extraction from n-dodecane as model diesel oil. 4-MDBT distribution coefficients, solvent selectivities, and extraction data also indicate that [emim][DEtPO4] is a better solvent for extractive desulfurization of n-dodecane than [emim][EtSO4]. For a solvent/n-dodecane mass ratio of 0.6, the sulfur content in n-dodecane decreases 17−24% and 5−15% for [emim][DEtPO4] and [emim][EtSO4], respectively. The quality of the data was ascertained by the Hand and Othmer−Tobias correlations, which ...

High performance sorbents for diesel oil desulfurization

Sorbents with different Ni loading supported on silica–alumina (SiAl) and activated carbon (AC) were synthesized and tested for removal of sulfur compounds from a model diesel oil, containing nearly 250 ppmw S as benzothiophene (BT), dibenzothiophene (DBT) and 4,6-dimethyldibenzothiophene (4,6-DMDBT). A state-of-art Commercial Ni-based sorbent and two Norit activated carbons were also tested for comparison. Moreover, the influence on sorbents uptake capacity of the presence of aromatics in amounts representative of real diesel oils was studied. Both commercial and home-made materials performed worse in presence of aromatic compounds. Probably, the latter competed with the refractory sulfur compounds (DBT and 4,6-DMDBT) in the adsorption on active sites. As a first important result of the investigation the sorbents carrying 45% and 30% of Ni on SiAl showed a breakthrough uptake capacity of nearly, respectively, 2 and 2.6 times higher than Commercial sorbent as a consequence of their higher Ni dispersion and surface area. Moreover, activated carbons and the sample with 28%Ni on AC showed an even higher breakthrough uptake capacities. In particular, the deposition of nickel on activated carbon is an innovative approach which takes advantage of the selectivity of Ni towards S-species and the high adsorptive capacity of AC support.

Deep Desulfurization of Diesel Fuel by Extraction with Task-Specific Ionic Liquids

Extraction of S-compounds from diesel oil by task-specific ionic liquids has been investigated. The influences of different ionic liquids, extraction time, extraction temperature, different S-compounds, the amount, and the recycling of ionic liquid were studied. This process is capable of removing up to 56% of dibenzothiophene in model diesel oil under optimum extraction conditions. At the same time, this process was applied to the real predesulfurized diesel oils. The results indicate that such a process could be an alternative to common hydrodesulfurization for deep desulfurization.