Hydrogen peroxide oxidative desulfurization of model diesel fuel mixtures in the presence of crown ethers and transition metal peroxo complexes

The catalytic ability of crown ethers and their complexes with transition metal cations in the desulfurization reaction of mixtures that simulate diesel fuel has been investigated. It has been found that the use of monoaza-15-crown-5-ethers with an admixture of NbCl₅ resulted in a fourfold decrease of the total sulfur content, thereby indicating partial oxidation of benzothiophenes and dibenzothiophenes. The complexation of azacrown ethers with NbCl₅ has been studied by ¹H NMR spectroscopy. A moderate efficiency of adsorption purification procedure using silica and alumina for both initial and oxidized model mixtures has been revealed.     

Ultrasound assisted photocatalytic oxidative desulfurization of model diesel fuel

Ultrasound assisted photocatalytic oxidation technology is an efficient and gentle technology to remove the organic sulfur from diesel. The influence parameters of catalytic oxidation phase include catalyst dosage, reaction temperature, oxidation time, hydrogen peroxide to diesel fuel ratio and time of the extraction process. Furthermore, the comparison of the results under two conditions of ultrasound irradiation and mechanical agitation are also specially examined. The obtained results indicate that under the optimal condition, ultrasound assisted oxidative desulfurization (UAOD) is more efficient for sulfur removal which the desulfurization degree can be reached 99.47%.     

Ultrasound assisted catalytic oxidative desulfurization of diesel oil using CdO nanoparticles

In 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%.     

过氧化叔戊醇对柴油氧化脱硫的工艺优化

以过氧化叔戊醇（TAHP）为氧化剂、MoO3/D 113为催化剂、N-甲基吡咯烷酮（NMP）为萃取剂,对焦化柴油进行氧化-萃取脱硫实验,考察了氧化温度、氧化时间、氧化剂用量、催化剂用量、萃取剂用量等工艺条件对脱硫率的影响.结果表明,最适宜的氧化-萃取脱硫工艺条件如下:氧化温度90 ℃,氧化时间2.5h,氧化剂/柴油（摩尔比）4,催化剂用量0.1g,萃取剂/柴油（体积比）1;在此条件下,柴油中硫化物的脱除率为96.8％,含硫量降至29.7 μg/g,柴油的回收率达98.6％.     

焦化柴油氧化脱硫脱氮工艺条件优化

研究了工艺条件对焦化柴油氧化萃取脱硫脱氮效果的影响。结果表明,氧化体系选用双氧水溶液(H2O2质量分数为30%)和甲酸,以磷钨酸为催化剂,以糠醛为萃取剂,在氧化温度为70℃,恒温回流搅拌时间为60 min,V(氧化体系)/V(焦化柴油)为0.4,V(甲酸)/V(双氧水溶液)为0.5,磷钨酸用量为0.20 g/L,采用二级萃取的优化工艺条件下,可将焦化柴油中硫的质量分数由817.563×10-6降至45.613×10-6,氮质量分数由734.577×10-6降至13.620×10-6。     

Diesel desulfurization using a ultrasound-assisted oxidative process

In this study, the removal of sulfur compounds from diesel samples using ultrasound-assisted oxidative desulfurization (UAODS) process in presence of different types of oxidizing agents was studied. Experiments were performed to assess the effects of influential parameters on the performance of UAODS process including ultrasonic irradiation time, oxidant type, mass ratio of oxidant to diesel fuel (oxidant: diesel), and finally acetic acid as an oxidative promoter. The efficiency of sulfur compounds removal from the diesel fuel dramatically improved using appropriate oxidative process with the assistance of ultrasound irradiation. H₂O₂ was found to be the most promising oxidant component whose concentration in the media directly affected total sulfur removal and thiol group conversion efficiencies. Using 4 wt% of H₂O₂ followed by 15 min of ultrasonic irradiation leaded to sulfur removal efficiency of 76% and thiol group conversion of 79% at ambient temperature and atmospheric pressure. Using acid acetic as the promoter of H₂O₂ also leaded to further sulfur compounds removal.     

Ultrasound assisted oxidative denitrification of diesel by formic acid/hydrogen peroxide

The basic nitrogen compounds in diesel were removed by using formic acid/hydrogen peroxide as oxidant under ultrasound, and alcohol was used as extractant. The effect of all factors on removing basic nitrogen compounds was investigated systematically. On the basis of single-factor experiments, the orthogonal experiments were done to optimize denitrification process. The optimum denitrification process was that volume ratio of formic acid to hydrogen peroxide was 3.0:1, volume ratio of oxidation system to diesel was 0.16:1, ultrasonic power was 64 W, reaction temperature was 313 K, ultrasonic radiation time was 2 min, and volume of alcohol was 16 mL. The content of basic nitrogen compounds in diesel was reduced from 85.79 to 3.56 μg/g, and the denitrification rate reached 95.85% under the optimum denitrification process. The treated diesel met the quality requirements.     

焦化柴油催化氧化吸附脱硫工艺条件优化

以磷钼酸季铵盐为催化剂,三氟乙酸为氧化剂,糠醛为萃取剂,采用催化氧化-萃取吸附组合工艺对焦化柴油进行脱硫处理。结果表明,在反应温度为60℃,氧化剂用量（V（氧化剂）/V（焦化柴油））为0.2,催化剂用量（m（催化剂）/V（焦化柴油））为8 g/L,反应时间为60 min,萃取剂用量（V（萃取剂）/V（焦化柴油））为1.0,萃取时间为30 m in的最佳工艺条件下,焦化柴油的硫质量分数可从1.05×10-3下降为42×10-6。     

Peroxide oxidative desulfurization of a mixture of nonhydrotreated vacuum gas oil and diesel fraction

Oxidative desulfurization of a model mixture on the basis of vacuum gas oil and diesel fuel by hydrogen peroxide in the presence of formic acid has been studied. A technology of a two-phase system with a phase-transfer catalyst has been employed for the desulfurization. The optimum reaction time is 6 h and the hydrogen peroxide: sulfur molar ratio is 4: 1. As a result of successive triple oxidative desulfurization, 90% of total sulfur is removed from the model mixture.     

The kinetics of oxidative desulfurization of diesel fraction with a hydrogen peroxide-formic acid mixture

The dependence of the oxidation rate of sulfur compounds on duration, oxidation temperature, and amount of the introducing oxidizer has been demonstrated with the straight-run diesel with a high initial sulfur content. The data for the oxidation rates of benzo- and dibenzothiophene homologues depending on the amount and the position of alkyl substituents in them during competing oxidation reactions of different diesel components have been obtained. The effective rate constants have been calculated for the oxidation reactions of the sulfur compounds during the oxidative desulfurization. The mechanism of the interaction of diesel sulfur compounds with the oxidant is proposed.     

Modeling of dibenzothiophene oxidative desulfurization using response surface methodology

The effect of reaction temperature, mixing speed and oxidant to catalyst volume ratio, including their interactions on the oxidative desulfurization of dibenzothiophene by using response surface methodology was studied. Hydrogen peroxide was used as oxidant and acetic acid as catalyst. The obtained model accurately predicts conversion of dibenzothiophene and the best conversion of 98.7% was observed at temperature 70°C, mixing speed of 1250 rpm and oxidant to catalyst volume ratio of 1:1. At high temperatures, a major limitation of the desulfurization process is the mass transfer and the high mixing speed is needed to achieve an efficient process.     

Extractive oxidative desulfurization of model oil/crude oil using KSF montmorillonite-supported 12-tungstophosphoric acid

12-Tungstophosphoric acid(PW) supported on KSF montmorillonite, PW/KSF, was used as catalyst for deep oxidative desulfurization(ODS) of mixed thiophenic compounds in model oil and crude oil under mild conditions using hydrogen peroxide(H_2O_2) as an oxidizing agent. A one-factor-at-a-time method was applied for optimizing the parameters such as temperature, reaction time, amount of catalyst, type of extractant and oxidant-tosulfur compounds(S-compounds) molar ratio. The corresponding products can be easily removed from the model oil by using ethanol as the best extractant. The results showed high catalytic activity of PW/KSF in the oxidative removal of dibenzothiophene(DBT) and mixed thiophenic model oil under atmospheric pressure at 75 ℃ in a biphasic system. To investigate the oxidation and adsorption effects of crude oil composition on ODS, the effects of cyclohexene, 1,7-octadiene and o-xylene with different concentrations were studied.     

Role of Mn/Al2O3 catalyst in deep oxidative desulfurization of diesel

Abstract

In this work, a series of supported manganese catalyst has been synthesized and utilized in oxidative desulfurization to remove 4,6-dimethyldibenzothiophene (4,6-DMDBT), dibenzothiophene (DBT) and thiophene. The influences of catalyst parameters were investigated including manganese precursors, manganese loading and calcination temperature in details. The synthesized catalyst was characterized by scanning electron microscopy (SEM), N₂ adsorption/desorption and X-ray diffraction (XRD) techniques. 90.2% of 4,6-DMDBT, 98.5% of DBT and 95.5% of thiophene conversion were achieved under mild operational conditions using 3Mn(NO₃)₂/Al₂O₃ at 500?°C calcination temperature. A slight decrease in desulfurization activity was observed after Mn/Al₂O₃ catalyst being used in five cycles ODS.     

Oxidative desulfurization of diesel fraction with hydrogen peroxide in the presence of catalysts based on transition metals

The oxidative desulfurization of a straight-run, nonhydrotreated diesel fraction (boiling range 178–342°C) containing benzothiophene, dibenzothiophene, their alkyl-substituted derivatives, and thioxanthene by the action of hydrogen peroxide in the presence of transition metal compounds (Na₂MoO₄, Na₂WO₄, NaVO₃, WO₃, tungstic acid, and heteropoly tungstate/molybdate H₃PMo₆W₆O₄0) in a biphasic system followed by the extraction of the oxidation products with dimethylformamide has been studied. The oxidation of the hydrocarbon fraction in the presence of heteropoly tungstate/molybdate under biphasic conditions provides for the removal of up to 82% of total sulfur.     

Catalyst for desulfurization of high-end-point diesel fuel

Translated from Khimiya i Tekhnologiya Topliv i Masel, No. 3, pp. 34–35, March, 1992.     

汽油和柴油脱硫技术进展

对目前清洁燃料油的生产技术进行了概述。随着环境保护意识的增强，世界各国将实施更加严格限制燃料油中硫含量的新规定，为此进一步开展清洁燃料油生产技术具有重要的意义。结合现有的燃料油脱硫技术，深入开展催化吸附脱硫、生物脱硫技术及组合脱硫技术应当成为燃料油脱硫技术的研究重点。     

Catalytic desulfurization of diesel fuel with a cavitation mixer

Technology was developed for cavitation activation of catalytic desulfurization of diesel fuels with a decrease in the residual content of mercaptan sulfur by 2-2.2 times with a simultaneous decrease in consumption of the catlaytic complex by 2 times.     

Ozone-assisted oxidative desulfurization of light oil fractions

A catalytic system for oxidative desulfurization has been created, which is a transition metal salt bearing an organic ligand and capable of forming an active oxidative complex in the interaction with ozone and further oxidizing sulfur compounds present in fuel followed by the adsorption of the oxidation products on silica gel. In this case, a direct contact of ozone with the fuel is avoided, making the process safer. The effect of the reaction and ozonation conditions on the desulfurization process has been studied. Total sulfur content was decreased to 180 ppm for the straight-run gasoline fraction and to 900 ppm for the diesel fraction.     

Oxidative desulfurization of catalytically cracked gasoline with hydrogen peroxide

Hydrogen peroxide desulfurization at 50°C of a catalytically cracked gasoline fraction containing methyl- and dimethylthiophenes and traces of benzothiophene and dibenzothiophene and boiling in the range of IBP-70°C in the presence of transition metal compounds Na₂MoO₄, Na₂WO₄, VOSO₄, and [Cu(NH₃)₄]CO₃ followed by adsorption on alumina has been studied. The successive oxidation of the hydrocarbon fraction in the presence of the copper and molybdenum compounds under phase transfer conditions ensures the removal of up to 96% of total sulfur.     

Doping effect of vanadium dioxide on oxidative desulfurization

VO2 (M) doped with different metals (Ti, Ce, Nb, Zr, W, and Mo) was successfully synthesized by the hydrothermal reduction process using oxalic acid as the reductant. The results showed that doping metals in the VO2 (M) lattice could enhance the oxidative desulfurization (ODS) activity. The DSC and Raman spectra revealed that VO2 (M) retained its monoclinic structure after doping. Mechanism for the improvement of ODS activity by doping was investigated. Electron transfer to V (V) atom occurs upon doping, and then V (V) changes into V (IV), which can promote the ODS reaction. This explanation can be confirmed by the fact that doping can promote the proportion of V (Ⅳ) after doping as revealed by the XPS analysis.