Oxidative Desulphurization Research Articles

Ultrasound-assisted oxidative desulphurization of coal using choline chloride-based deep eutectic solvents

Ultrasound-assisted oxidative desulphurization of coal using choline chloride-based deep eutectic solvents

Performance of a novel cobalt phthalocyanine sulfonamide‐based catalyst for oxidative desulphurization of gas condensate

AbstractSulphur compounds and mercaptans in gas condensate cause corrosion problems, poison catalysts in catalytic processes, and have adverse environmental impact through SOx emission upon combustion. Therefore, it is essential to remove sulphur and mercaptan from gas condensate to standard levels. In this study, the oxidative desulphurization (ODS) process in the presence of a cobalt phthalocyanine sulfonamide‐based catalyst was investigated. The homogeneous catalyst containing 23 wt.% active material was used and optimum operating conditions of temperature, volume ratio of caustic to gas condensate, caustic concentration, and solvent amount were determined to decrease sulphur content to less than 500 ppm and mercaptan to less than 200 ppm. The catalyst consumption in all experiments was kept constant at a minimum level (0.01 g/400 mL gas condensate). Results showed that this catalyst improved the reaction rate in the lower temperature and lower caustic to feed ratio and lower caustic concentration. The maximum sulphur removal was obtained at 5°C and 4 vol.% of caustic to gas condensate ratio at 16.7 wt.% of caustic concentration. Moreover, this catalyst improved sulphur removal from the gas condensate to about 5% compared to caustic sweeting without catalyst. Sulphur compounds had higher solubility in acetone rather than methanol, and sulphur removal by acetone was 96% while it was 91% for methanol. Finally, the economical and acceptable solvent for sulfoxides removal was methanol with 5% volume fraction.

Degradation of diazinon by dielectric barrier discharge plasma

Pesticides are chemical compounds widely used in crop pest control, ensuring high productivity and product quality control. However, pesticides are toxic and can be bioaccumulative, and their excessive use causes environmental and health impacts. In this study, the potential of atmospheric cold plasma to degrade diazinon present in water was investigated. For the degradation process, a dielectric barrier discharge (DBD) plasma system was used to process diazinon at a varying voltage (10, 15, and 20 kV), excitation frequency (200, 400, 600, 800, and 1000 Hz), and exposure time (10, 20, and 30 min). The concentration of diazinon and the identification of the by-products were analyzed by gas chromatography coupled to mass spectrum (GC-MS). DBD plasma processing efficiently degraded diazinon, reaching a maximum degradation of 9.44 ± 0.09 mg/L, sufficient to bring diazinon-contaminated waters to safe levels. Analysis of variance indicated that increasing voltage and treatment time and low plasma excitation frequencies increased diazinon degradation. Two parallel degradation routes were proposed for diazinon degradation by cold plasma consisting of an oxidative desulphurization route and a hydrolytic route followed by a ring-opening reaction.

Ozonation/extraction coupled non‐catalytic desulphurization of VGO/natural gas condensate

AbstractThe desulphurization of hydrocarbon fuels with high sulphur content and a wide variety of sulphur‐containing compounds brings significant challenges. In the present work, the non‐catalytic desulphurization of vacuum gas oil (VGO) and natural gas condensate mixed fuel has been investigated. In this regard, ozone was employed as the oxidant in a bubble column gas–liquid contactor, and an extraction step was further incorporated. The effects of the oxidation reactor scheme, ozonation time, and extraction with different solvents, applying pre‐ and post‐extraction strategies (i.e., ozonation/extraction/extraction and extraction/ozonation/extraction), have been studied. It was found that pre‐extraction of mixed fuel increases the oxidative desulphurization (ODS) efficiency due to the removal of light sulphur‐containing compounds (SCCs). N‐methyl‐2‐pyrrolidone (NMP) has been found to be the most effective extraction agent, removing 44% of sulphur by pure extraction and 77.4% by ozonation + extraction. However, in terms of fuel loss, dimethylformamide (DMF) performs better than NMP, and it has been shown to be the most appropriate solvent for achieving a 90% desulphurization ratio. Finally, it was found that the applied procedure could effectively remove the wide range of SCCs, especially refractive components such as benzothiophene (BT) and dibenzothiophene (DBT).

Oxidation of Sulphur pollutants in model and real fuels using hydrodynamic cavitation

Hydrodynamic Cavitation (HC) offers an attractive platform for intensifying oxidative desulphurization of fuels. In the first part of this work, we present new results on oxidising single ring thiophene in a model fuel over the extended range of volume fraction of organic phase from 2.5 to 80 v/v %. We also present influence of type and scale of HC device on performance of oxidative desulphurization. Further experiments revealed that oxidising radicals generated in-situ by HC alone were not able to oxidise dual ring thiophenes. External catalyst (formic acid) and oxidising agents (hydrogen peroxide, H2O2) were therefore used with HC. Based on our prior work with acoustic cavitation (AC), the volumetric ratios for H2O2 and formic acid were identified as 0.95 v/v % and 6.25 v/v % respectively. The data of oxidation of dual ring thiophenes with n-dodecane and n-hexane as model fuels and typical transport fuels (diesel, kerosene, and petrol) using these oxidant and catalyst is presented. The observed performance with HC was compared with results obtained from a stirred tank and AC set-up. The presented data indicates that HC is able to intensify oxidation of sulphur species. The presented results provide a sound basis for further developments on HC based oxidative desulphurization processes.

Optimization of the Oxidative Desulphurization of Residual Oil Using Hydrogen Peroxide

The role of fuel in global economy cannot be overemphasized, it is necessary to develop new and more efficient technologies in desulphurization processes at a low cost. This research focuses on optimization of desulphurization using oxidative method for higher yields, utilizing dual acetic/formic acid catalyst on residual oil with sulphur concentration > 0.50%wt and emphasizes the improvement of physicochemical properties primarily suitable for use in fuels where regulation is becoming more stringent. The process was conducted using H₂O₂ oxidant concentration 12.5-25.0% (w/w), CH₃COOH/HCOOH acid catalyst mixture 12.5-22.0% (w/w), and reaction temperature 40-60°C. Optimization of the desulphurization parameters was done using response surface methodology based on Box-Behnken design. The optimum yield of desulphurization (60.93%) was achieved at the oxidant 18.75% (w/w), acetic/formic mixture of 17.25% (w/w), and reaction temperature of 50°C. In general, the experimentally confirmatory figures in two solutions of 63.29 ± 0.47% and 61.04 ± 0.13% match the predicted values of 62.82% and 60.91%, respectively. The total sulphur content in residual oil was reduced from 0.67 to 0.26%wt. GC-MS of the untreated sample confirm the presence of 1,2-benzisothiazole,3-(hexahydro-1H-azepin-1-yl)-1,1-dioxide, Nickel(II)bis(N,N-dihexyldithiocarbamate and Diethyl[3-[n-octadecylmercapto]-P-n-butyl-anilino methy lene] malonate with a total percentage peak area of 11.83%. In the treated sample shows no sulphur compounds. The physicochemical analysis for both treated and untreated residual oil according to ASTM were found to be within acceptable limit except sulphur content of untreated sample. After the desulphurization, treated residual oil shows a remarkable improvement in the physicochemical parameters. Hence can be applicable in industrial process and automobiles with very low sulphur emission.

Formulation of heterometallic ZIF-8@Cu/Ni/ZnO@CNTs heterostructure photocatalyst for Ultra-Deep desulphurization of coal and fuels

Developing efficient methods for deep desulphurization of commercial fuel is critical because of the requirements to limit sulphur concentrations below 10 ppm. Among various methods, recently photocatalytic oxidative desulphurization (PODS) has attracted great attention as it does not require high temperature and pressure. Herein, we report a novel heterostructure h-ZIF-8@Cu/Ni/ZnO@CNTs, having heterometallic ZIF-8 (h-ZIF-8) coated on Cu/Ni/ZnO (h-ZIF-8@Cu/Ni/ZnO), supported over carbon nanotubes (CNTs) sponge for selective PODS of both coal and fuel. The Cu/Ni/ZnO-based ternary hybrid metal oxide was first stabilized on a CNTs sponge followed by a surface reaction of metal particles with 2-methyl imidazole to in-situ form h-ZIF-8 shell on the surface of Cu/Ni/ZnO. The resulting h-ZIF-8@Cu/Ni/ZnO@CNTs exhibited high surface area (1283.47 m2/g), meso/microporous backbone, narrow bandgap (2.52 eV), and a large number of available active sites. Owing to these characteristics, the h-ZIF-8@Cu/Ni/ZnO@CNTs exhibited excellent photocatalytic response for the removal of organic sulphur with a removal rate of 0.76 Kg m−3 day−1 compared to control ZIF-8@ZnO@CNTs (0.4 Kg m−3 day−1). The removal rate was further enhanced to 3.3 Kg m−3 day−1 for dibenzothiophene, confirming the higher PODS potential of the designed photocatalyst for refractory organic sulphur. In summary, the h-ZIF-8@Cu/Ni/ZnO@CNTs possess promising characteristics to be applied for the desulphurization of commercial fuels.

Removal of single and dual ring thiophene’s from dodecane using cavitation based processes

Utilising cavitation for enhancing oxidative desulphurization has been investigated for nearly-two decades with recent investigations shifting focus from low-capacity acoustic cavitation (AC) to scalable hydrodynamic cavitation (HC). This work focuses on developing a viable means for removing thiophene’s from fuels. In the first phase of this work, use of vortex based HC devices for removal of single and dual ring thiophenes from dodecane was investigated. HC was shown to be able to remove single ring thiophene from dodecane without using any external catalyst or additives. However, in absence of catalyst or additives, it was not possible to remove dual ring thiophenes such as dibenzothiophene using HC. Therefore, in the second phase of this work, various strategies based on use of catalyst or additives to augment cavitation based process were investigated. AC based experiments were opted for shortlisting suitable catalysts and additives for intensifying cavitation based processes. The influence of using oxidant (H2O2) and carboxylic acid catalysts on efficacy of removal of dual ring thiophenes is presented. Several conditions were tested, and the optimal volumetric ratios of 0.95 v/v % H2O2 and 6.25 v/v % HCOOH was identified and utilised throughout the remainder of the study. Regeneration of extractant which accumulates oxidised sulphur species from dodecane was also investigated using AC. The additives and process conditions reported in this work are useful for enhancing desulphurization performance.

Biosolids-based catalyst for oxidative desulphurization of drop-in fuels derived from waste fats

In this work, the catalytic performance of a biosolids-based catalyst was tested in the oxidative desulphurization process of a model fuel solution containing benzothiophene ([S] of 500 ppm), as well as sulphur-rich products from a two-step thermal conversion process of brown grease to renewable hydrocarbons using biosolids as a water replacement during the hydrolysis step. The catalytic results of the biosolids-based material were compared with a classical Fenton-like reagent and a non-catalytic system. Biosolids-based catalyst outperformed the other systems at low temperature with a full desulphurization of benzothiophene solution achieved at 60 °C after 3 h and a good recyclability after four catalytic runs at 80 °C for 3 h. The desulphurization was less effective for hydrolysed fatty acids and crude pyrolysis oil derived from the conversion of brown grease to renewable hydrocarbons, which was due to the composition of the sulphur containing compounds, but still reached 87.7 ± 3.0 % and 74.7 ± 9.5 %, respectively.

Mesopore-encaged V-Mn oxides: Progressive insertion approach triggering reconstructed active sites to enhance catalytic oxidative desulfuration

The oxidative desulphurization (ODS) has become mainly popular by rapid catalytic oxidation of dibenzothiophene (DBT) relied on efficient heterogeneous catalyst. V-based catalytic active species were regarded as the potential option in the activity-preferred ODS systems. Herein, we reported the re-dispersion of vanadium oxide (VO x ) on the mesoporous silica modified with manganese oxide (Mn 3 O 4 ) through one progressive insertion approach of metal oxides in the silica. Impressively, mesopore-encaged vanadium-manganese oxides in the silica (VMn-MS) as the admirable output of excellent ODS catalyst was demonstrated compared to other monometal-modified counterparts and one-pot implanted one. The characterization results revealed the post-implanted VO x species not only deposited around the pre-covered Mn 3 O 4 on the mesoporous surface but also inserted the surface layer of Mn 3 O 4 inducing the amorphous evolution of aggregated Mn 3 O 4 and the reconstruction of final active sites. This integrated approach made the reconstructed active species afford more exposed catalytic sites and the tailored surface redox cycles owing to the electronic communication of V-Mn. The catalytic results demonstrated the excellent catalytic desulphurization efficiency (∼100%) during 60 min at 80 °C, which made the sulphur content reduce to 6 mg·L -1 , remarkably superior to other comparative samples. The outstanding catalytic performance of VMn-MS catalyst can be ascribed to the synergistic effect of V-Mn dual metals rendering two different reaction pathways, which includes free-radical reaction and ring-forming reaction, where Mn site acted as active center triggering reactive free radicals which could be further optimized by surrounded V sites around Mn sites to promote the ODS process.

Synthesis of hydrophobic nanosized hierarchical titanosilicate-1 zeolites by an alkali-etching protocol and their enhanced performance in catalytic oxidative desulphurization of fuels

Nanosized hierarchical titanosilicate-1 zeolites (nanoTS-1_D) with variable Ti doping content were synthesized by a simple and sequent two-step procedure consisting of microporous TS-1 nanocrystal synthesis through steam-assisted dry-gel conversion and post alkali-etching treatment for mesopore formation. Comprehensive characterizations, e.g. XRD, N2 sorption isotherms, DLS, UV-Vis, SEM, TEM and water-droplet contact angle, indicated that the resultant nanoTS-1_D materials not only possess abundant intracrystal mesopores and high surface area, but importantly maintain the intrinsic surface hydrophobicity as those of microporous TS-1 zeolites. Consequently, they showed the expected superior catalytic performance in both bulky cyclohexene/cyclooctene epoxidation and phenol hydroxylation probe reactions, contrast to the microporous TS-1 and amorphous Ti-MCM-41 mesoporous counterparts. In the oxidative desulfurization of fuels, they exhibited 100% removal ability for thiophene and its bulky derivatives and excellent recyclability. In addition, a new Ti-dopant directed alkali-etching mechanism has been proposed to illustrate the synthesis of high-specific-surface-area nanoTS-1_D.

Modified Mesoporous HMS Supported V/W for Oxidative Desulfurization of Dibenzothiophene

Two V/W-HMS (hexagonal mesoporous silica) nanostructures were synthesized with various vanadium and tungsten loadings. And their catalytic activities were investigated in oxidative desulphurization of dibenzothiophene (DBT) in model diesel fuel. The catalysts were characterized using X-ray powder diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared (FT-IR) spectroscopy, and N_2 physical adsorption-desorption (BET/BJH) techniques. The best V/W-HMS catalyst exhibited high catalytic activity, capable of converting more than 95% of DBT in the model diesel fuel under the optimum reaction condition (0.05 gr 1:4 of catalyst, T=60°C, t=2h). After doping of vanadium with tungsten, it was found that bandgap of the catalyst was reduced and its catalytic performance was improved effectively. The catalytic activity remained unchanged even after 6 recycling processes. The reaction kinetics, mechanism, and bandgap energy of the catalysts were also investigated.

Исследование влияния микроволнового излучения на процесс десульфуризации мазута

Many chemical processes are intensified by microwave radiation. The main factor determining the usefulness of microwaves in most transformations of organic compounds is the reaction time reduction to obtain the maximum yield of the target product. The presence of sulphur in oil and petroleum products is detrimental to refining equipment, and also has a negative impact on the environment in the form of waste generated during refining. In this connection development of methods on removal of sulphurcontaining compounds from oil products and oil by their transformation (in particular oxidation) and subsequent removal is very significant. Oxidative desulphurisation of fuel oil takes up to several hours depending on the reagents used. In this work an attempt has been made to significantly reduce the duration of the process. Oxidation of sulphur-containing organic compounds in fuel oil under microwave radiation has been considered, which proceeds in the presence of an oxidizer (hydrogen peroxide) and a catalyst (titanium dioxide). It was found that the oxidative desulphurization of fuel oil at microwave radiation proceeds effectively and quickly within 1--5 min. The achieved degree of desulphurization is 66 % when exposed to microwave radiation for 5 min. The influence of the amount of water in the reaction mixture on the efficiency of oxidative desulphurization of fuel oil under microwave radiation has been studied; it was found that the optimum ratio of water : fuel oil was (1--1.2) : 1

Designing biopolymer-based artificial peroxidase for oxidative removal of dibenzothiophene from a model diesel fuel

Naturally occurring peroxidases are important for living organisms and have manifold utility in industries. However, lack of stability in harsh reaction conditions hinders wide applicability of such enzymes. Thus, suitable alternative is vital which can endure severe reaction conditions. As a substitute of natural peroxidase, herein, biopolymer-based polyelectrolyte complexes (PECs) coordinated with Fen+ is proposed as macromolecular peroxidase mimicking systems. Three PECs were engineered via complexation of protonated chitosan and alginate with Fe2+ (Fe2+-PEC), Fe3+ (Fe3+-PEC), and Fe3O4 (Fe3O4-PEC), respectively. Computational study showed the Fe3+-PEC was highly stable with abundant electrostatic and intramolecular hydrogen bonding interactions. The versatility of the Fe-PECs as artificial peroxidase biocatalysts was probed by two types of peroxidase assays – ABTS oxidation in buffer systems (pH 4.0 and 7.0) and pyrogallol oxidation in organic solvents (acetonitrile, ethyl acetate and toluene). Overall, Fe3+-PEC showed remarkably high peroxidase activity both in aqueous buffers and in organic solvents, whereas, Fe3O4-PEC showed least catalytic activity. Finally, as a proof of concept, the ability of the biocatalyst to carry out deep oxidative desulphurization was demonstrated envisaging removal of dibenzothiophene from model fossil fuel in a sustainable way.

Oxidative Desulfurization of Diesel from the Topping Plant using 1-Butyl-3-Methylimidazolium Hydrogen Sulfate [Bmim][HSO4] as Catalyst

This investigation was carried out with the purpose of reducing the sulphur content in diesel from the topping plant and avoiding air pollution, due to the presence of SOx in the emissions, at the same time reduced the corrosion rate in the equipment, machinery or mechanical components of the industry. An oxidative desulphurization (ODS) process was carried out with ionic liquid (1-butyl-3-methyl imidazolium hydrogen sulfate [BMIM][HSO4]) that serves as a solvent and catalyst. H2O2 (30 % wt) was used as an oxidizing agent, because it is benign to the environment. A maximum of 43.14% removal was obtained at a volumetric ratio VIL/Vdiesel (1:1), molar ratio H2O2/S (5) and reaction time (2 hours). In addition, the IL was evaluated after subjecting it to a regeneration process, being able to recycle it only once until it is saturated again; also the physical-chemical properties of diesel were studied before and after of exposed it to the ODS process.

Catalytic oxidative desulphurization of pyrolytic oils to fuels over different waste derived carbon-based catalysts

In this work, we reported the conversion though carbothermal process of two catalysts produced by pyrolyzing exhausted coffee and waste tires. We tailored the surface with anchored iron nanoparticles through a facile carbothermal route and tested them for catalytic oxidative desulphurization of high sulphur content oil derived from tires pyrolysis. We studied their activity in a biphasic system under different conditions reaching a desulphurization of up to of 60% by using an oil with a sulphur concentration of up to 7139 ppm. The extensive characterization proved the reliability of those materials as promising catalysts for upgrading of sulphur rich drop-in fuels.

Manufacturing a Composite Material Based on Carbon Nanotubes and Its Use in the Oxidative Desulphurization of Oil Products

Manufacturing a Composite Material Based on Carbon Nanotubes and Its Use in the Oxidative Desulphurization of Oil Products

Creating a Composite Material Based on Carbon Nanotubes and Its Use in the Oxidative Desulphurization of Oil Products

Creating a Composite Material Based on Carbon Nanotubes and Its Use in the Oxidative Desulphurization of Oil Products

A new synthetic composite nano-catalyst achieving an environmentally Friendly fuel by batch oxidative desulfurization

Production of clean fuel has recently become one of the most important goals for petroleum refining industries. The objective of this work is to obtain such clean fuel using simple and easy process under safe conditions. For this purpose, batch oxidative desulfurization (ODS) process is considered here to remove sulfur compounds found in light gas oil using a new composite synthetic homemade nano-catalyst. First the support for the new catalyst, which is HY zeolite nanoparticles, is prepared using sol-gel method. The support is then employed to generate the synthetic composite nano-catalyst which is made of copper oxide and nickel oxide using the impregnation method with different proportions of the active components such as: 5% CuO +25 % NiO, 10 % CuO +20 % NiO, 15 % CuO +15 % NiO, 20 % CuO +10 % NiO and 25 % CuO +5% NiO. An excellent distribution of the active metals with high surface area and pore volume as a result high activity has obtained. A fully automated batch reactor is used for the oxidative desulphurization of sulfur compounds and the performance of the new nano-catalyst at different safe reaction conditions (reaction temperature from 353−413K, reaction time from 30−90min) is evaluated in terms of sulfur removal.

Oxidative desulphurization of gasoline fractions from Azerbaijani oils

The paper studies the process of oxidative desulphurization of catalytic cracking and coking gasoline types and their close cut fractions. Direct oxidation studies of these gasoline fractions using hydrogen peroxide in the presence of heterogenic catalysts containing Mo and Co ions have been carried out for the oxidation of sulfur compounds and their further extraction via ion fluids enabling extraction of sulfur-organic compounds in the form of concentrates of oily sulfoxides and sulfanoles. Thus, desulfurization degree of gasoline fractions comprises 70-80 % - ultimately without change in gasoline octane number.