Desulfurization Of Diesel Fuels Research Articles

Co-based metal-organic frameworks confined N-hydroxyphthalimide for enhancing aerobic desulfurization of diesel fuels

N-hydroxyphthalimide (NHPI) is a powerful green nitrogen-containing free radical catalyst, while the leaching of homogeneous NHPI remains a crucial obstacle. Herein, the cobalt-based metal–organic frameworks (Co-based MOFs) were introduced as the supports and co-catalysts to successfully confine the NHPI catalyst. NH3-TPD characterization confirmed that the heterogeneous catalyst NHPI@Co-MOF containing carboxyl groups linker exhibits more assertive acidity, facilitating the activation of O2 to generate active radicals O2•− that determined the catalytic activity. Owing to these features, NHPI@Co-MOF-DA with two carboxyl groups as the linker achieved 98 % of DBT conversion at 120 °C. Moreover, the DBT conversion of the used catalyst reached 95 % after being recycled 10 times. The distinctive design strategy provided valuable insights into the selection of suitable organic linkers to enhance the synergistic effect of metal cobalt with NHPI in the oxidative desulfurization (ODS) process, broadening the research horizon of MOF hybrids in the construction of efficient ODS applications.

Deep Desulfurization of Diesel Fuel by Guard Bed Adsorption of Activated Carbon and Locally Prepared Cu-Y Zeolite

Desulfurization of a simulated diesel fuel by different adsorbents was studied in a fixed-bed adsorption process operated at ambient temperature and pressure. Three different adsorption beds were used, commercial activated carbon, Cu-Y zeolite, and layered bed of 15wt% activated carbon followed by Cu-Y zeolite.Initially Y-zeolite was prepared from Iraqi rice husk and then impregnated with copper. In general, the adsorbents tested for total sulfur adsorption capacity at break through followed the order Ac/Cu-Y zeolite>Cu-Y zeolite>Ac. The best adsorbent, Ac/Cu-Y zeolite is capable of producing more than 30 cm3 of simulated diesel fuel per gram of adsorbent with a weighted average content of 5 ppm-S, while Cu-Y zeolite producing of about 20 cm3 of diesel fuel per gram of adsorbent with a weighted average content of 2ppm-S. Activated carbon breaks through almost immediately.

Multi-walled carbon nanotubes coated on defective tungsten oxide for deep oxidative desulfurization of diesel fuels

The interface properties of metal oxides considerably affect the catalyst activity during the removal process of persistent organic sulfur pollutant in diesel fuels. Herein, we report that the hydrophilicity of defective metal oxides can be well shielded by refining the interface. As a proof of point, multi-walled carbon nanotubes (CNTs) were employed as a solid modifier to be wound on the Mo-doped W18O49 nanowire clusters (MoWO-x@CNTs) for enhanced catalytic performance. The results show that the full conversion of dibenzothiophene is achieved within 12.5 min. The turnover frequency value is up to 79.7 h−1, much higher than other catalysts. Compared with the bare W18O49, the MoWO-x@CNTs exploits a rough hierarchical structure, which overcomes the limitation of the hydrophilic W18O49 interface. Furthermore, the persistent organic sulfur in diesel fuels is <6.2 ppm, achieving the goal of ultra-deep desulfurization. Besides, no more secondary extraction is required, which also alleviating environmental pollution caused by the abuse of organic waste.

Rational Design of Caprolactam-Based Deep Eutectic Solvents for Extractive Desulfurization of Diesel Fuel and Mechanism Study

Rational Design of Caprolactam-Based Deep Eutectic Solvents for Extractive Desulfurization of Diesel Fuel and Mechanism Study

Ultrafast Oxidative Desulfurization of Diesel Fuel Catalyzed by Polyoxometalate-Based Catalyst Immobilized on Functionalized Y-Sba-15

Ultrafast Oxidative Desulfurization of Diesel Fuel Catalyzed by Polyoxometalate-Based Catalyst Immobilized on Functionalized Y-Sba-15

Amphiphilic Halloysite Nanotube Enclosing Molybdenum Oxide as Nanoreactor for Efficient Desulfurization of Diesel Fuels

Amphiphilic Halloysite Nanotube Enclosing Molybdenum Oxide as Nanoreactor for Efficient Desulfurization of Diesel Fuels

In situ fabrication of hollow silica confined defective molybdenum oxide for enhanced catalytic oxidative desulfurization of diesel fuels

Hollow nanomaterials are considered to be excellent carriers due to the nanoreactor confinement effect, which can improve the performance of the supported catalysts. In this work, a hollow silica confined defective molybdenum oxide catalyst (MoOx/HS) was obtained by using phosphomolybdic acid grafted polystyrenes as the templates. Compared with solid silica-supported catalyst (MoO3/SS), MoOx/HS could make better use of active components to achieve complete desulfurization. The calculated turnover value (TON) of MoOx/HS was 1.37 mol/mol, which is three times more than that of MoO3/SS. The presence of oxygen defects also facilitated the oxidation reaction. In addition, the catalyst MoOx/HS had good stability and selectivity, and the desulfurization rate of dibenzothiophene (DBT) remained 95.3% after being recycled for 5 times.

Life cycle assessment of environmental impacts associated with oxidative desulfurization of diesel fuels catalyzed by metal-free reduced graphene oxide

This study aimed to analyze the environmental impacts of the oxidative desulfurization (ODS) process catalyzed by metal-free reduced graphene oxide (rGO) through life cycle assessment (LCA). The environmental impacts study containing the rGO production process, the ODS process, the comparison of different oxidants and solvents was developed. This study was performed by using ReCiPe 2016 V1.03 Hierarchist midpoint as well as endpoint approach and SimaPro software. For the production of 1 kg rGO, the results showed that hydrochloric acid (washing), sulfuric acid (mixing), hydrazine (reduction) and electricity were four main contributors in this process, and this process showed a significant impact on human health 14.21 Pt followed by ecosystem 0.845 Pt and resources 0.164 Pt. For the production of 1 kg desulfurized oil (400 ppm), main environmental impacts were terrestrial ecotoxicity (43.256 kg 1,4-DCB), global warming (41.058 kg CO2), human non-carcinogenic toxicity (19.570 kg 1,4-DCB) and fossil resource scarcity (13.178 kg oil), and the main contributors were electricity, diesel oil and acetonitrile. The whole ODS process also showed a greatest effect on human health. For two common oxidants hydrogen peroxide and oxygen used in ODS, hydrogen peroxide showed a greater impact than oxygen. On the other hand, for three common solvents employed in ODS, N-methyl-2-pyrrolidone had a more serious impact on human health followed by acetonitrile and N,N-dimethylformamide. As such, LCA results demonstrated the detailed environmental impacts originated from the catalytic ODS, hence elucidating systematic guidance for its future development toward practicality.

Oxidative Desulfurization of Diesel Fuel Using Three Kinds of Carboxylic Acids Supported by Iron(III) Chloride

Aqueous carboxylic acids (CA) are generally used as attractive catalytic extractants in the field of desulfurization of petroleum products. In the present study, a triple system consisting of CA-ferric chloride-hydrogen peroxide has been used for the removal of aromatic S-compounds from partially hydrotreated diesel by liquid−liquid oxidative-extraction. The influence of various operating parameters affecting the oxidative desulfurization was experimentally investigated. Formic acid (HCOOH), acetic acid (CH3COOH), and propanoic acid (CH3CH2COOH) as aqueous solutions with hydrogen peroxide and iron(III) chloride (FeCl3) as oxidant and catalytic agent, respectively, were used. All experiments were carried out at 55°C with different oxidant to sulfur mole ratios (nH2O2/nS) (15–36), CA to sulfur mole ratios (nCA/nS) (2–26), and oxidation reaction times (5–25 min). Within 25 min of the treatment, a maximum elimination of aromatic S-compounds of 65.1% was obtained when molar ratio of oxidant to sulfur (nH2O2/nS) was 36 and molar ratio of CA to sulfur (nCA/nS) was 26. Surface tension calculations for the CAs demonstrated that the average void radius of the acids has a pronounced effect on the fitting of S-compounds from diesel fuel into acids and is important to sulfur removal. Further, increasing the desulfurization efficiency was also energetically affected in the presence of ferric halide. The obtention of the sulfur removal ability value was noticeably higher than was achieved by employing similar reaction conditions in the absence of FeCl3.

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 ...

Catalytic Oxidative-Extractive Deep Desulfurization of Diesel Fuel by N-methyl-2-pyrrolidone-Based Protic Acidic Ionic Liquids (PAILs)

Inexpensive and low-viscosity Protic Acidic Ionic Liquids (PAILs) of N-metheyl-2-pyrrolidone formate, acetate, and propionate abbreviated as [Hnmp][HCOO], [Hnmp][CH3COO] and [Hnmp][CH3CH2COO] respectively, were prepared and characterized by FT-IR and H-NMR. Deep oxidative and extractive desulfurization of a simulated oil and a real diesel containing 1000 ppmw sulfur were studied under the catalysis of the proposed PAILs without additional carboxylic acid and extraction solvent in the system. The desulfurization efficiency in this study was influenced by both amounts of PAILs and concentration of the produced peroxy acids from H2O2. Comparing to [Hnmp][HCOO], [Hnmp][CH3COO] and [Hnmp][CH3CH2COO] had a relatively higher extraction ability however the weaker acidic properties of them resulted in a lower activation of H2O2 to produce peroxy acids and finally led to lower oxidative desulfurization (ODS) efficiency in the same condition. Additionally, the neutralization reaction may not be efficiently gone to the right hand by weaker acids. The effects of the main process variables were studied in detail. The highest desulfurization yield of 97% for BT and 99% for DBT and 4,6-DMDBT, were achieved using [Hnmp][HCOO] in the ODS system at a temperature of 40 °C, H2O2/sulfur molar ratio of 10, VPAIL/Voil of 0.2, and a reaction time of 90 min. The immiscibility of the proposed PAILs in this study with the oil phase caused the easy separation of them after desulfurization. The possible ODS pathway was also proposed.

Regeneration study of ecat-R as adsorbent for denitrogenation and desulfurization of diesel fuels

The purpose of this paper is to present the third stage of regeneration for ecat: deactivated or equilibrium catalysts which are waste from fluidized catalytic cracking (FCC) units. This stage is going to compose a complete circular economy (CE) model and increase the life cycle of the catalyst. The third stage of regeneration, after the adsorption process for sulfur and nitrogen compounds from real diesel, was assessed using as solvents: acetone (propanone), ethanol, benzene and toluene. For sulfur and nitrogen compounds, ethanol achieved the best performance. The variations of physical and chemical properties of regenerated ecats in the cycles of adsorption and desorption were evaluated using x-ray diffraction, x-ray fluorescence, nitrogen adsorptiondesorpion, thermogravimetric and differential thermal analysis, scanning electron microscopy and Fourier-transform infrared spectroscopy. The recovery rate over four cycles is superior for sulfur compounds. After all cycles, ecat-R- -SA exhibited 5.09% reduction in the recovery for sulfur and 24.58% reduction in the recovery for nitrogen. The nitrogen adsorption-desorption analysis suggests the adsorption of compounds by ecat-R may be more correlated with the adsorption sites than with specific area. Overall, the results of this work are promising and allows for ecat to integrate a complete CE model.

Deep oxidative desulfurization of diesel fuels using homogeneous and SBA-15-supported peroxophosphotungstate catalysts

A combination of catalytic oxidation and extraction was used for the desulfurization of a model diesel containing benzothiophene, dibenzothiophene and 4,6-dimethyldibenzothiophene, or a real diesel sample with a sulfur content of 2300 ppm. The catalysts used were the soluble peroxo compound (nBu4N)3{PO4[WO(O2)2]4} (PW4) and a supported material denoted as PW4@TMA-SBA-15 that was prepared by immobilization of PW4 in an ordered mesoporous silica (SBA-15) derivatized with propyltrimethylammonium groups (TMA). The supported catalyst was characterized by FT-IR, FT-Raman, 31P and 13C MAS NMR spectroscopies, powder X-ray diffraction and scanning electron microscopy. Under optimized conditions (H2O2/S molar ratio = 7, 70 °C, acetonitrile as extraction solvent), both catalysts led to complete desulfurization of the model diesel within a reaction time of 2 h. The desulfurization systems could be recycled 10 times with only a slight decrease in performance being observed between the 9th and 10th oxidative desulfurization cycles. Application of the PW4 system to the real diesel led to an outstanding desulfurization efficiency of 89% after a reaction time of 2 h.

High efficient and selective oxidative desulfurization of diesel fuel using dual-function [Omim]FeCl4 as catalyst/extractant

Lewis acidic ionic liquid (IL) of 1-octyl-3-methylimidazolium tetrachloroferrates ([Omim]FeCl4) with an interesting structure, was synthesized and introduced as a highly effective catalyst and also as extractive solvent in oxidative desulfurization (ODS) of model and real diesel fuels with H2O2 oxidant. FT-IR, H-NMR and TG-DSC analysis were used for characterization of the prepared ILs. GC-FID, GC-PFPD and GC–MS measurements were also employed to investigate the ODS yields and mechanism. The adequate structure and acidic properties of [Omim]FeCl4 allowed removal of thiophenic compounds with high efficiency in an extraction and then oxidation process. The effects of the major processing variables on ODS performance of [Omim]FeCl4 were studied in detail. At the optimal conditions of VIL/Voil of 1/10, O/S molar ratio of 5, reaction time of 15 min and room temperature, BT and DBT were totally eliminated, and 4,6-DMDBT was removed by 99% from the model diesel. Moreover, [Omim]FeCl4 was able to desulfurize two real diesel fuels containing 590 and 2573 ppmw of sulfur with the efficiency of 85% and 61.2%, respectively, at a short time of 15 min. The experimental results also showed a remarkable selectivity of 0.919 for elimination of thiophenic compounds in competition with non-sulfur aromatic model of 2-methyl naphthalene. [Omim]FeCl4 exhibited an excellent recyclability with no significant decline in activity after use in 7 reaction cycles. An overall mechanism was also suggested for desulfurization by the proposed system.

Oxidative Desulfurization of Diesel Fuel Using a Brønsted Acidic Ionic Liquid Supported on Silica Gel

A novel heterogeneous catalyst was prepared by supporting the ionic liquid (IL) 1-octyl-3-methylimidazolium hydrogen sulfate ([Omim][HSO4]) in the silica-gel matrix using a sol–gel method and employed in oxidative desulfurization of a model oil containing dibenzothiophene (DBT) and real diesel fuel. The properties of the supported ionic liquid (SIL) were characterized by FT-IR, TGA, BET-BJH, SEM-EDS, and PSA. The results showed that the ionic liquid was successfully incorporated in the silica-gel matrix, and a catalyst having high surface area was prepared. The effects of H2O2/DBT molar ratio (O/S), temperature, SIL/oil mass ratio, initial S content, and sulfur species on the sulfur removal of the model oil were studied. The highest DBT removal efficiency of 99.1% was obtained with the prepared catalyst having 17 wt % supported IL loading in the conditions of SIL/oil (w/w) of 1:3 and O/S molar ratio of 5 in 50 min at 50 °C. The prepared catalyst can be efficiently applied in oxidative desulfurization with...

A Review on Bio- And Adsorptive Desulfurization of Diesel Fuel

A Review on Bio- And Adsorptive Desulfurization of Diesel Fuel

Diesel Fuel Desulfurization via Adsorption with the Aid of Activated Carbon: Laboratory- and Pilot-Scale Studies

The present work is an experimental investigation of commercial diesel fuel liquid desulfurization via adsorption under mild conditions. The sorbent employed was a commercial high surface area activated carbon (AC), and studies involved both laboratory- and pilot-scale experiments performed in dedicated fixed-bed setups. Under laboratory-scale conditions, maximum sulfur removal measured exceeded 90%, while according to breakthrough curves the total sulfur content remained below 2 ppmw for up to 20–22 mL of processed diesel per gram of sorbent. Process scaling-up by a factor of 15 showed a moderate negative effect, with the respective breakthrough fuel amount (total sulfur ≤2 ppmw) being ∼15–17 mL processed fuel/g sorbent. Several sorbent regeneration strategies were studied under laboratory-scale conditions. The one with the highest restoration of initial (i.e., fresh state) AC performance involved heating under vacuum (200 mbara) up to 200 °C and subsequent washing of the material with a binary organic s...

Brønsted–Lewis Acidic Ionic Liquids and Application in Oxidative Desulfurization of Diesel Fuel

Study on alternative methods to hydrodesulfurization is always an interesting area, because of the ineffectiveness for hydrodesulfurization to remove some cyclic sulfur compounds (S-compounds) and the high cost from harsh operation conditions and expensive catalyst, among which oxidative desulfurization (ODS) using ionic liquids (ILs) as solvent is intensively studied recently. Here, we synthesize a series of Brønsted–Lewis acidic ILs of N-methylpyrrolidonium zinc chloride ([Hnmp]Clx/(ZnCl2)y, x:y from 2:1 to 1:2) and investigate the ODS of both model diesel fuel composed of n-octane and dibenzothiophene and real FCC feedstock where such ILs are used as extractant and catalyst and 30 wt % H2O2 is used as oxidant, involving the factors such as IL composition (or x:y), temperature, dose of oxidant (or molar ratio of O/S), dose of IL (or mass ratio of IL/oil), recycling of IL and multistage desulfurization. IL composition has an important effect on sulfur removal (S-removal) efficiency, and [Hnmp]Cl/ZnCl2 (x:y = 1, the structure nature was characterized with ESI-MS and FT-IR) shows the highest desulfurization capability with good recyclability. With [Hnmp]Cl/ZnCl2, the S-content in model diesel fuel can be reduced to <1 ppm from 500 ppm with 99.9% S-removal at 75 °C, IL/oil = 1/3 and O/S = 8 after only one stage, while the sulfur removal for real FCC diesel fuel is less than 38% in one stage and can reach 83% after five stages, which might be ascribed to more-complex S-species in real fluidized catalytic cracking (FCC) diesel fuel as indicated by gas chromatography–sulfur chemiluminescence detection (GC-SCD) chromatogram analyses. The sulfur content (S-content) in FCC diesel fuel, however, can be reduced to 5.3 ppm with a total S-removal of 97.6% after five-stage ODS with one more extractive desulfurization with furfural as the extractant. This work shows that such Brønsted–Lewis acidic ILs are potential solvents used in ODS to produce clean fuel oils.

New Gas-Phase Catalytic Oxidative Processes for Desulfurization of Diesel Fuel

&lt;p&gt;An effective gas-phase oxidative desulfurization (ODS) process was proposed. The process was studied in a laboratory reactor with a proprietary catalyst at 300-400 ºС and ambient pressure with model fuels represented by thiophene, dibenzothiophene (DBT) and 4,6-dimethyldibenzothiophene (DMDBT) dissolved in octane, isooctane or toluene. The reactivity of different sulfur containing molecules in ODS was shown to increase in the sequence: thiophene &amp;lt; DBT &amp;lt; DMDBT. The main sulfur containing product of oxidation of these compounds was SO&lt;sub&gt;2&lt;/sub&gt;. During the gas-phase ODS both processes of sulfur species oxidation and processes of their adsorption were observed and studied. Based on the conducted studies, different ODS process designs comprising its integration with adsorption and regeneration processes and with conventional hydrodesulfurization (HDS) process were proposed. One scheme is based on alternating regimes of ODS and catalyst regeneration in two reactors: sulfur is removed from organic feedstock by oxidation and adsorption in one reactor while simultaneous regeneration of the catalyst that has accumulated sulfur compounds takes place in another reactor. Two other schemes are based on joint use of ODS and HDS. The conventional HDS process is most effective for removal of low-boiling sulfur containing compounds reactive with respect to hydrogen, while removal of refractory sulfur compounds, such as DMDBT is more easily achieved by gas phase ODS. Thus the combination of these processes is expected to be most efficient for deep desulfurization of diesel fuel.&lt;/p&gt;

Desulfurization of Diesel Fuel by Oxidation and Solvent Extraction

This research presents a study in ultra-desulfurization of diesel fuel produced from conventional hydro desulfurization process, using oxidation and solvent extraction techniques. Dibenzothiophene (DBT) was the organosulfur compound that had been detected in sulfur removal. The oxidation process used hydrogen peroxide as an oxidant and acetic acid as homogeneous catalyst . The solvent extraction process used acetonitrile (ACN) and N-methyl – 2 - pyrrolidone (NMP) as extractants . Also the effect of five parameters (stirring speed :150 , 250 , 350 , and 450) rpm, temperature (30 , 40 , 45 , and 50) oC, oxidant/simulated diesel fuel ratio (0.5 , 0.75 , 1 , and 1.5) , catalyst/oxidant ratio(0.125,0.25,0.5,and0.75) , and solvent/simulated diesel fuel ratio(0.5,0.6,0.75,and1) were examined as well as solvent type. The results exhibit that the highest removal of sulfur is 98.5% using NMP solvent while it is 95.8% for ACN solvent. The set of conditions that show the highest sulfur removal is: stirring speed of 350 rpm , temperature 50oC , oxidant/simulated diesel fuel ratio 1 , catalyst/oxidant ratio 0.5 , solvent/simulated diesel fuel ratio 1. These best conditions were applied upon real diesel fuel (produced from Al-Dora refinery)with 1000 ppm sulfur content . It was found that sulfur removal was 64.4% using ACN solvent and 75% using NMP solvent.&#x0D; &#x0D;