Desulfurization Of Oil Research Articles

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...

Highly catalytic oxidative desulfurization and denitrogenation of diesel using anchored-silica-gel vanadium-substituted Dawson-type polyoxometalate

The aim of this article is to study the extractive-catalytic oxidative desulfurization (ECODS) of the model oil containing several model S-containing compounds as well as N-containing compound using a heterogeneous vanadium substituted Dawson-type polyoxometalate catalyst under atmospheric pressure and temperature lower than 100 °C. The catalyst was prepared by ion exchange with alkyl ammonium derivatives covalently anchored to silica gel. The potential of this methodology was illustrated by oxidation of 100% quinoline and 80% of total sulfur in model oil containing 500 ppmw sulfur and 70% of total sulfur in model oil 1500 ppmw in less than 30 min of reaction, in the absence of solvent. However, when acetonitrile was employed as an extractive solvent, the desulfurization was increased considerably. Under the reaction conditions, activated catalyst and acetonitrile, solvent to oil ratio 1:6, could remove approximately 100% of quinoline, 95% of sulfur from 500-ppmw model oil, 87% of sulfur from 1500-ppmw model oil in less than 30 min. The catalyst is very active in ECODS and can be reused fifth times from 500-ppmw model oil and third times from 1500-ppmw model oil without an important decrease in activity. The ECODS could remove 83% of total sulfur from 1235-ppmw-S real diesel.

Decomposition of Oxidized Sulfur-Containing Components of Crude Oil and Petrochemicals Under Conditions of Nanoheterogeneous Catalysis

The catalytic decomposition of dibenzothiophene sulfone is studied in the presence of nanosized iron(III) oxide with an average particle diameter of 10–12 nm; it is synthesized by the thermolysis of iron(III) acetylacetonate in the medium of diphenyl ether. The optimum conditions of the process are ascertained by varying the temperature and time of the reaction and the concentration of the nanosized catalyst. It is shown that the oxidative desulfurization of crude oil and petrochemicals may occur with the oxidized sulfur-containing components being decomposed under mild conditions in the presence of nanosized iron(III) oxide at the second stage. In some cases, the degree of desulfurization is above 80%.

Synergetic Effect of Cobalt-Incorporated Acid-Activated GAC for Adsorptive Desulfurization of DBT under Mild Conditions

The present study explores the usage of acetic-acid-treated cobalt-modified activated carbon as an adsorbent material for the adsorptive desulfurization of DBT-containing model oil. Modification of granular activated carbon (GAC) with acetic acid treatment and incorporation of cobalt species in GAC framework significantly improved its adsorption capacity by improving oxygen-containing functional groups and acidic sites. The surface area of GAC improved from 257 to 393.8 m2/g when it was treated with cobalt species and acid. The average size of the Co3O4 crystallites in the Co-loaded activated carbon was found to be 13.8 nm. The effect of various operating parameters such as cobalt loading, adsorbent dose, temperature, and time was studied. Furthermore, the reusability of spent adsorbent and the effect of the presence of other aromatics compounds were also investigated. Under optimized operating conditions, ∼92% of DBT removal was achieved. The equilibrium data of DBT adsorption were analyzed by Langmuir, ...

Theoretical Study of Oil Desulfuration by Ammonium-Based Deep Eutectic Solvents

A theoretical study using quantum chemistry and molecular dynamics methods is reported on the properties of deep eutectic solvent prepared by tetrabutylammonium bromide and formic acid regarding oil desulfurization. The objective of the work is to obtain molecular level insights into the mechanisms of extractive desulfuration by deep eutectic solvents for designing suitable processes for deep desulfuration purposes. The intermolecular interactions of solvent molecules and relevant organosulfur compounds (thiophene, benzothiophene, and dibenzothiophene) are analyzed together with the liquid structure of solvent + sulfur compounds as a function of organosulfur content. Interfacial properties between the solvent and model oil (n-octane) with different contents of organosulfur compounds are also studied to analyze the molecular level mechanism of liquid–liquid equilibria. Likewise, free energies of solvation in the solvent and in n-octane are calculated to justify the partition of organosulfur compounds betwe...

Oxidative Removal of Organo-sulfur Species via H2O2 Oxidation Catalyzed by Lacunary Keggin 11-tungstophosphates

The lacunary Keggin 11-tungstophosphates were evaluated as catalysts for the oxidation of dibenzothiophene with hydrogen peroxide as oxidant in normal octane/acetonitrile biphasic system. The Na5[PW11O39Ni] exhibited good catalytic activity with the desulfurization efficiency above 99.5%. The key factors affecting the reaction, including amount of catalyst, O/S molar ratio, catalyst dosage and initial sulfur content, were investigated, whereby the favorable conditions were determined. The presence and the oxidative effect of the peroxo-heteropoly species in the oxidative reaction were determined in the contrast experiments. Moreover, the Na5[PW11O39Ni] catalyst was confirmed to have a high potential for deep desulfurization of diesel oil.

Residue Oil Desulfurization Using Oxidation and Extraction Method

This study successfully improved the performance of oxidative desulfurization method to reduce sulfur content from residue oil (condensate) with modifications of oxidation and extraction steps which was repeated for several stages. Residue oil used in this study contain 386.2 ppm of initial sulfur content. In oxidation process, H2O2 as oxidizer and acid as catalyst were used within temperature range of 30–60 °C and time interval from 30 to 120 min. In extraction process, various alcohol solvents (methanol, ethanol, and propanol) were used with the temperature of 30 °C in 30 min for every residue oil ratio to solvent (v/v). The best reducing sulfur result achieved was 35.9 ppm or 90.7% desulfurization. This result was achieved after 4 recursively extractions using ethanol as solvent. This study successfully reduced sulfur content in residue oil to meet the international standard (< 50 ppm).

Ultrasound assisted catalytic oxidative desulfurization of diesel oil using CdO nanoparticles

ABSTRACTIn this paper, sol-gel auto-combustion method is used to synthesize CdO nanoparticles. The synthesised sample is characterized for its size and structure using X-Ray diffraction (XRD) and scanning electron microscopy (SEM) techniques. And some molecular groups containing in the nanoparticle are detected by Fourier transformer Infra Red (FT-IR). Then, the sample is used to remove the organic sulfur from hydrogenation desulfurated diesel under ultrasonic condition. The influence parameters including catalyst dosage, oxidant dosage, oxidation temperature, oxidation time and extracting times are been researched. The obtained result indicates that under the optimal condition, the desulfurization degree can be reached 72.7%.

Desulfurization of Diesel over Ni/ZnO Adsorbent Prepared by Coprecipitation

Ni/ZnO adsorbents with various Ni/Zn molar ratios were prepared by coprecipitation; their adsorption capacity in reactive adsorption desulfurization (RADS) of diesel oil was investigated. Ni/ZnO exhibits much higher adsorption performance than pure Ni and pure ZnO. The Ni content plays a crucial role in determining RADS activity over Ni/ZnO; the sulfur capacity depends on the ZnO content in Ni/ZnO. The Ni4/Zn6 adsorbent shows the optimal performance; the sulfur content in diesel oil is reduced to less than 5 ppm in first 60 h and less than 15 ppm in next 68 h.

Deep catalytic oxidative desulfurization of fuels by novel Lewis acidic ionic liquids

In this work, novel Lewis acidic ionic liquids [ODBU]Cl/nZnCl2 (n = 1, 2, 3, 4 and 5) with alkylated 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) cation and ZnCl2-based complex anion have been developed and utilized in extraction combined with oxidative desulfurization (ECODS) of both model oil and diesel fuel with hydrogen peroxide (H2O2, 30 wt%) as an oxidant. It was observed that the ECODS performance could be effectively optimized by the change of ZnCl2 proportion. Some important reaction parameters such as reaction temperature, molar ratio of O/S, mass ratio of IL/oil and sulfide species were systematically investigated. Furthermore, the ILs could be reused for at least six cycles without noticeable changes in desulfurization performance as well as its chemical structure, thus revealing its good reusability. Finally, [ODBU]Cl/3ZnCl2 was employed in the ECODS of a hydrogenated diesel, the S-content could be reduced from 559.7 ppm to 4.8 ppm with 99.2% sulfur removal via a one-step process under mild conditions.

Three-dimensional ordered phosphotungstic acid/TiO2 with superior catalytic activity for oxidative desulfurization

A series of phosphotungstic acid (HPW)/TiO2 materials with three-dimensional continuous and ordered macroporous structure, ranging from 130 nm to 300 nm in size, are synthesized by colloidal crystal templates and used as catalysts for oxidative desulfurization (ODS) of model oil. The structure and properties of 3DOM HPW/TiO2 catalysts are characterized by powder X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscopy (TEM), N2 adsorption–desorption isotherms, inductively coupled plasma-optical emission spectrophotometer (ICP) and fourier transform infrared spectra (FT-IR). Characterization results demonstrate that all the HPW/TiO2 samples possess a large BET surface area and three-dimensional ordered macroporous structure with Keggin-type HPW dispersed homogeneously in TiO2 framework. 3DOM HPW/TiO2 with an average pore diameter around 250 nm presents the highest catalytic activity for dibenzothiophene (DBT), which can be attributed to the combination of its large enough macropores allowing for efficient mass transport and its high surface area enabling sufficient exposure of catalytic active sites. Furthermore, the catalyst is recovered and reused for seven runs with no obviously decrease in catalytic activity.

Oil desulfurization using deep eutectic solvents as sustainable and economical extractants via liquid-liquid extraction: Experimental and PC-SAFT predictions

The reduction of the sulfur content in crude oil is of utmost importance in order to meet the stringent environmental regulations. Thiophene and its derivatives are considered key substances to be separated from the crude oil. In previous works, six deep eutectic solvents (DESs) based on tetraethylammonium chloride, tetrahexylammonium bromide and methyltriphenylphosphonium bromide as hydrogen bond acceptors (HBAs) and polyols (ethylene glycol and glycerol) as hydrogen bond donors (HBDs) were successfully applied for the extraction of thiophene from {n-alkane + thiophene} mixtures via liquid-liquid extraction. One of the objectives of this work was to study the effect of the aliphatic hydrocarbon type/length (e.g. n-hexane vs n-octane) on the extraction performance of the same DESs. Extraction performance was evaluated by the selectivity and the thiophene distribution coefficient. Based on new experimental data, higher selectivities and lower thiophene distribution coefficients were obtained when thiophene was extracted from n-octane instead of n-hexane. Another objective was to predict the phase behavior of the ternary systems {n-alkane + thiophene + DES} using Perturbed-Chain Statistical Associating Fluid Theory (PC-SAFT). The PC-SAFT “pseudo-pure component” approach was applied, in which a DES was considered as a pseudo-pure compound (not a mixture). The pure-component parameters of the DESs were obtained by fitting to liquid density data, which were measured at temperatures between 298.2 K and 323.2 K. Binary interaction parameters were fitted to experimental binary LLE data for the systems {n-alkane + DES} and {thiophene + DES} at 298.2 K and atmospheric pressure, while the LLE data of the ternary systems {n-alkane + thiophene + DES} were fully predicted. It was found that the distribution coefficients and selectivity of the ternary systems containing DESs could be qualitatively well predicted using this model.

A novel La3+–Zn2+–Al3+–MoO42− layered double hydroxides photocatalyst for the decomposition of dibenzothiophene in diesel oil

ABSTRACTA new type of photocatalyst, La3+-Zn2+-Al3+-MoO42− layered double hydroxide (LDH) (La:Zn:Al = 1:7:2), was prepared by a complexing agent-assisted homogeneous precipitation technique. The LDHs were used as catalysts for the desulfurization of diesel oil under UV irradiation. As revealed by the results, the catalyst showed superior desulfurization efficiency and recycling performance. Under UV irradiation, the desulfurization efficiency was 84% in 60 min. In La3+–Zn2+–Al3+–MoO42− LDHs, the introduction of MoO42− increased the interlayer space for promoting the adsorption of dibenzothiophene, and MoO42− might act as the active sites for the oxidation of dibenzothiophene, resulting in the high desulfurization efficiency.

Effect of the Type of Ammonium Salt on the Extractive Desulfurization of Fuels Using Deep Eutectic Solvents

In a previous work, we proved that the deep eutectic solvents (DESs) consisting of mixtures of tetraalkylammonium salts with polyols are promising candidates for oil desulfurization based on the obtained liquid–liquid equilibrium (LLE) data. In this study, the capability of DESs containing other salts (e.g., different alkyl chain lengths or different functional groups on the ammonium cation) for the extraction of thiophene from {n-hexane + thiophene} mixtures via LLE was evaluated. Therefore, four DESs composed of tetraethylammonium chloride or methyltriphenylphosphonium bromide as hydrogen bond acceptors and ethylene glycol or glycerol as hydrogen bond donors were prepared. Thereafter, the binary solubilities of the aliphatic hydrocarbon (n-hexane) and the thiophene in DESs were measured at 298.2 K and atmospheric pressure. Next, ternary liquid–liquid equilibrium (LLE) data for the four ternary systems {n-hexane + thiophene + DES} were measured at 298.2 K and atmospheric pressure. The conductor-like scre...

Heavy gas oil biodesulfurization using a low‐cost bacterial consortium

AbstractBACKGROUNDPetroleum and its derivatives usually contain large amounts of sulfur. During the combustion of fossil fuels, sulfur is liberated to the atmosphere in the form of one of the most noxious pollutants: sulfur dioxide (SOx). The removal of sulfur content to the ultralow levels demanded by worldwide legislation has been a challenge to the refinery industry, principally due to the inefficiency of conventional processes, such as hydrodesulfurization, which are not capable of removing the recalcitrant sulfur compounds. Biodesulfurization is a biological process that removes these sulfur compound pollutants from hydrocarbons. However, there are several unsolved technological difficulties associated with this procedure, including the development of a stable and efficient biocatalyst, and a low‐cost culture medium. Thus, the use of a bacterial consortium (BC) as a substitute for both biocatalyst and nutritional medium was studied in order to improve the biodesulfurization process.RESULTSThe desulfurization activity was determined at different temperatures and BC concentrations. An efficient desulfurization capacity (71.2%) was observed using only 5% (w/w) of BC at 45 °C. At this temperature, the total time required for biodesulfurization was substantially reduced; only 2 h was required to achieve the highest desulfurization capacity.CONCLUSIONThe BC can be used as a substitute for biocatalysts and nutritional media for heavy gas oil desulfurization. Desulfurization capacity using the BC was similar to that achieved using other pure bacterial strains and culture media, and the process time was diminished. BC use represents an important improvement in biodesulfurization technology. © 2018 Society of Chemical Industry

A New Approach to Deep Desulfurization of Light Cycle Oil over Ni2P Catalysts: Combined Selective Oxidation and Hydrotreating

Amphiphilic phosphotungstic acid (A-PTA) and Ni2P/SBA-15 catalysts were prepared to apply for selective oxidation of refractory sulfur compounds in light cycle oils and hydrotreating of the oxidized S compounds, respectively. Physical properties of the catalyst samples were analyzed by BET, CO uptake chemisorption, and TEM. Structural properties for the supported Ni2P catalysts were analyzed by X-ray diffraction (XRD) and extended X-ray absorption fine structure (XAFS) spectroscopy. The selective oxidation of S compounds in the LCO feed was conducted in a batch reactor at H2O2/S ratio of 10, atmospheric pressure and 353 K and then the products were fed to a continuous flow fixed-bed reactor for hydrotreating at 623 K, 3.0 MPa, and LHSV’s of 0.5–2.0 h−1. A-PTA catalyst showed a high oxidation conversion of 95% for a real LCO feed. The following hydrotreating led to a hydrodesulfurization (HDS) conversion of 99.6% and a hydrodenitrogenation (HDN) conversion of 94.7% over Ni2P/SBA-15, which were much higher than those of direct hydrotreating results which gave an HDS conversion of 63.5% and an HDN conversion of 17.5% based on the same LHSV of 2.0 h−1. It was revealed that the reduction in refractory nitrogen compounds after oxidative treatment contributed to the increase of the following HDS activity.

Desulfurization of gas oil using a distillation, extraction and hydrotreating-based integrated process

In the present study, an integrated process (IP) was conceptualized for carrying out the deep desulfurization of gas oil (GO) in a cost-effective and environment-friendly way. This IP is based on the best salient features of distillation, solvent extraction, and hydrotreating processes. The practical applicability of the IP is illustrated using experimental data and estimated responses. The proposed IP can produce gas oil containing 73 ppmw compared to 328 ppmw sulfur produced using standalone hydrotreating process (SHP) from GO having sulfur 1.36% under same operating conditions of temperature and pressure, catalyst, and catalyst loading in hydrotreating reactor. The chemical hydrogen consumption of IP was found to be 48.1% less compared to SHP for the same concentrations of sulfur and aromatic in treated gas oil. Overall, 95.6% of GO can be converted into low sulfur gas oil using mild operating conditions in hydrotreating zone of IP. Rest 4.4% hydrocarbons of SRGO can be used either as valuable carbon black feedstock or feed to delayed coking unit or as aromatic rich rubber processing solvent.

New Conduct in the Adsorptive Removal of Sulfur Compounds by New Nickel–Molybdenum Adsorbent

The article states the first preparation of NiMo layered double hydroxide (LDH) adsorbent for the removal of dibenzothiophene (DBT) form n-heptane solution and desulfurization of gas oil. The existence of (Mo6+) in Ni2+Mo6+ LDH was proven by X-ray photoelectron spectroscopy (XPS), while X-ray diffraction and X-ray fluorescence patterns, Fourier transform infrared spectra, scanning electron microscopy images, and differential scanning calorimetry–thermogravimetric analysis and Brunauer–Emmett–Teller analysis were applied for the composition and surface characterizations. Experimentally, NiMo LDH exhibited a different conduct in the adsorption elimination of sulfur in the existence of aromatics; the sulfur uptake was increased with the increase of the aromatic content in accordance with its own highly charged surface as a result of the formation of +4 balancing charges between Ni2+and Mo6+ through the brucite layers. The material achieved adsorption capacity of 48.8 mg g–1 sulfur for DBT at 25 °C follows a ...

The confined space electron transfer in phosphotungstate intercalated ZnAl-LDHs enhances its photocatalytic performance for oxidation/extraction desulfurization of model oil in air

Synergetic interaction between phosphotungstate and hydrotalcites in confined space enhances electron transfer and photo catalytic oxidation of DBT.

Desulfurization by MOFs as Sorbents for Thiophene Sulfides

Metal-organic frameworks UMCM-150 [Cu3(BHTC)2] and its heterobimetallic analogue Co1Cu2(BHTC)2 based on an asymmetrical ligand, biphenyl-3,4’,5-tricarboxylate (H3BHTC), were studied for desulfurization of model oils. The adsorption experiments were conducted under room temperature and atmospheric pressure. The total sulfur concentration of model oils was 250 ppmw determined by WK-2D coulomb integrated micro-analyzer through adding benzothiophene (BT) and dibenzothiophene (DBT) into liquid alkanes. Adsorptive desulfurization experiments were conducted in a consecutive fixed bed adsorption system. The results indicate that Cu3(BHTC)2 has a higher sulfur-capacity than Co1Cu2(BHTC)2. Taking DBT as an example, Cu3(BHTC)2 and Co1Cu2(BHTC)2 have breakthrough adsorption capacities of 10.6 and 5.8 g S/kg of sorbent for model oils.