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.     

The Research of Ultra-deep Desulfurization in Diesel via Ultrasonic Irradiation Under the Catalytic System of H2O2-CH3COOH-FeSO4

Abstract

In recent years, many countries have drawn up strict laws regarding the sulfur-containing compounds of fossil fuels, especially the gasoline and diese. Ultra-deep desulfurization of fuel is a main component of fossil fuel development. The experiment imposes the photochemistry field on the catalytic oxidation system in order to broaden the newly desulfurization technology. The sulfur-containing compounds, such as dibenzothiophene (DBT) and its derivatives, in diesel fuel are oxidized to corresponding sulfones using H₂O₂-CH₃COOH-FeSO₄ oxidation systems via ultrasonic irradiation. Later, the oxidized sulfur compounds (sulfones) are extracted by a suitable polar solvent. The influences of the catalytic system, reaction time, and ultrasonic source (frequency, intensity) are tested on desulfurization efficiency. Experimental results show that the removal efficiency of the sulfur compound could amount to 97.5%, and the recovery of oil is above 92% under the catalytic system of H₂O₂-CH₃COOH-FeSO₄ by the assistance of ultrasound.     

超声波辐照浸渍法制备MnO2/γ-A12O3催化剂及其柴油催化氧化脱硫性能

 分别采用超声波辐照浸渍法和普通浸渍法制备了MnO₂/γ-Al₂O₃催化剂,运用电感耦合等离子体原子发射光谱（ICP-AES）和X射线衍射（XRD）对催化剂进行表征,在空气-异丁醛-MnO₂/γ-Al₂O₃体系中评价其对加氢柴油的氧化脱硫催化性能,并考察了反应温度、异丁醛用量、空气流量、溶剂类型和剂/油体积比对柴油氧化脱硫反应的影响。结果表明,超声波辐照浸渍法制备的MnO₂/γ-Al₂O₃催化剂对柴油氧化脱硫的催化性能明显优于普通浸渍法制备的催化剂。最适宜的催化柴油氧化脱硫反应的条件为：乙腈为溶剂、加氢柴油30 mL、温度35℃、异丁醛20 mmol、空气流量0.06 L/min、超声波辐照浸渍法制备的MnO₂/γ-Al₂O₃催化剂0.08 g、剂/油体积比1/6和催化氧化时间10 min。在此条件下可将柴油硫质量分数从542μg/g 降至31μg/g,柴油脱硫率和回收率分别为94.3%和93.3%。     

Oxidative Desulfurization of Fuel Oil with Hydrogen Peroxide Catalyzed by Keggin-type Polyoxotungstate in a DC Magnetic Field

Abstract

The oxidation of sulfur-containing compounds was conducted in a DC magnetic field-assisted system, composed of model compound or diesel, 30 wt% hydrogen peroxide, and an iron mono-substituted Keggin-type heteropolytungstate [(C₄H₉)₄N]₄ [PW₁₁Fe(H₂O)O₃₉] catalyst. By combining oxidative desulfurization (ODS) in a magnetic field and acetonitrile extraction, when magnetic field intensity was at 17.3 mT, the removal efficiency of the model compound dibenzothiophene (DBT) in petroleum ether with 1,000 ppm S can reach 98% at 70°C within 30 min with O/S ratio = 3 and catalyst dosage 5%, with 2% increase over that without magnetic field assistance. Under the same reaction conditions, the sulfur level of diesel oil was reduced from 5,647 to 508 ppm. This shows that the DC magnetic field facilitates the oxidation of sulfur-bearing compounds, which allowed greater sulfur removal efficiency under milder reaction conditions.     

A Novel Technology for Desulfurization of FCC Diesel Fuels: Combination of Hydrogenation and Oxidation-assisted Ultrasound

Abstract

This new route that integrates with hydrodesulfurization (HDS) and ultra-sound-assisted oxidation desulfurization (UAODS) technology can be studied to decrease the sulfur content of high sulfuric FCC diesel fuel. In the integrating technology, the conventional HDS unit continues to produce below 500 μg/g hydrotreated diesel fuels, with UAODS unit used to make sulfur content below 50 μg/g, or even below 10 μg/g of diesel fuels. Since it has been discovered that cavitation can be originated from ultrasonic irradiation in water, ultrasound is an increasingly used tool to enhance chemical process rate. The addition of Fenton's reagent can enhance the sono-oxidative desulfurization efficiency for diesel fuels. UAODS has more advantages in removing thiophene and alkyl-thiophenes that are less reactive than other organosulfur species present in these hydrocarbon streams (e.g., alkyl sulfides, mercaptans) using HDS technology. The key to success is that the oxidative desulfurization process must be cost-effective versus the HDS revamp alternative available to refiners.     

Diesel desulfurization using a UV-photocatalytic process

In this paper, the use of ultraviolet irradiation using TiO₂ as a photocatalyst for diesel desulfurization was studied in a batch reactor. The effects of operational parameters such as operation time, the presence of oxidant, oxidant type, and irradiation power on the performance of the desulfurization process were investigated. The results revealed that total sulfur and thiol group removals from diesel samples were about 61.91% and 58.64%, respectively, at the power of 18 W of UV irradiation and 2 wt% H₂O₂ as an oxidizing agent using 40 min of irradiation as an optimum time required. It was also found that hydrogen peroxide is the most promising oxidant for the desulfurization of diesel fuel. By increasing the power of ultraviolet irradiation from 18 W to 30 W, total sulfur removal and thiol group conversion were increased to 90% and 88%, respectively. However, total sulfur removal and thiol group conversion at 30 W ultraviolet irradiation with 2 wt% TiO₂ and without using any oxidants were about zero and 14%, respectively.     

Deep Oxidative Desulfurization of Dibenzothiophene in Simulated Diesel with Tungstate and H2O2 in Ionic Liquids

Abstract

A green extraction and catalytic oxidative desulfurization (ECODS) system composed of simple tungsten-containing catalyst, 30 wt% H₂O₂, and ionic liquids was discovered suitable for the deep removal of dibenzothiophene (DBT) in simulated diesel. In the case of the system comprising Na₂WO₄ · 2H₂O, 30 wt% H₂O₂ and 1-butyl-3-methylimidazolium tetrafluoroborate ([Bmim]BF₄), the removal of DBT could reach 99.7% at 60°C for 3 hr, which was superior to mere solvent extraction with ionic liquid or catalytic oxidation without ionic liquid. This desulfurization system could be recycled five times with a small decrease in activity.     

Oxidative Desulfurization of Fuel Oil: Modeling Based on Artificial Neural Network

Abstract

Oxidative desulfurization of fuel oil was investigated using a process consisting of oxidation and distillation steps. In the oxidation step, various organic carboxylic acid/H₂ O₂ systems, especially acetic acid/H₂ O₂, were used as oxidant. They oxidize both easy and refractory sulfur compounds and convert them into oxidized sulfur compounds. The oxidized sulfur compounds are finally removed from fuel oil by distillation in the presence of water. The sulfur content of fuel oil was decreased to levels as low as 20 ppm (up to 90%) in a short contact time, ambient temperature, and atmospheric pressure. The results showed that applying this process did not have any deleterious influence on the distillation characteristic, composition, and content of fuel oil that was examined. An artificial neural network, using back propagation (BP), was also utilized for modeling oxidative desulfuration process of fuel oil. The comparison between the output of ANN modeling and the experimental data showed satisfactory agreement.     

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

A new type of photocatalyst, La³⁺-Zn²⁺-Al³⁺-MoO₄^2? 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⁺–MoO₄^2? LDHs, the introduction of MoO₄^2? increased the interlayer space for promoting the adsorption of dibenzothiophene, and MoO₄^2? might act as the active sites for the oxidation of dibenzothiophene, resulting in the high desulfurization efficiency.     

Optimization of Oxidative Desulfurization of Dibenzothiophene Using a Coordinated Ionic Liquid as Catalytic Solvent

Abstract

Oxidative desulfurization (ODS) of dibenzothiophene (DBT) in n-octane with hydrogen peroxide/acetic acid using a quaternary ammonium coordinated ionic liquid (IL) (C₄H₉)₄NBr · 2C₆H₁₁NO as catalytic solvent has been studied. The ODS mechanism by coordinated ionic liquid [(C₄H₉)₄NBr · 2C₆H₁₁NO] was also carried out. The sulfur-containing compounds in model oil were extracted into ionic liquid phase and oxidized to their corresponding sulfones by H₂O₂. The effect factors for desulfurization of model oil were investigated in detail by means of monofactorial and orthogonal experiments (L₁₆(4)⁴). The results showed that the desulfurization efficiency of model oil could reach 98.6% under the optimal conditions of oxidation time, oxidation temperature, molar ratio of H₂O₂/sulfur (O/S), and volume ratio of model oil to coordinated ionic liquid were 30 min, 50°C, 16, and 1, respectively. The influences to the desulfurization efficiency of DBT decreased in the following order: volume ratio of model oil to coordinated ionic liquid (C₄H₉)₄NBr · 2C₆H₁₁NO (V_{model oil}/V_IL) > molar ratio of O/S > oxidation temperature > oxidation time, according to extreme analysis of the orthogonal test. The coordinated ionic liquid (C₄H₉)₄NBr · 2C₆H₁₁NO can be recycled 5 times without a significant decrease in desulfurization.     

Phenol degradation by advanced Fenton process in combination with ultrasonic irradiation

In this study, a successful degradation of phenol was achieved by means of coupling nano-sized zero-valent iron (NZVI), H₂O₂ and 20 kHz ultrasound irradiation. The effect of H₂O₂ concentration, initial pH, ultrasonic irradiation time and NZVI addition on the degradation efficiency was investigated and the kinetics of the process was discussed. The results showed that the degradation rate increased by increasing the H₂O₂ concentration and the irradiation time but decreased with the increase of the initial pH value. These results clearly indicate that the degradation of phenol is intensified in the presence of NZVI and H₂O₂, which can be attributed to enhanced production of OH radicals in the system. The degradation rate in the presence of NZVI was faster than in its absence. Thus, an appropriate selection of operating conditions will lead to an economical and highly efficient technology with eventual large-scale commercial applications for the degradation of organic pollutants in aqueous effluents.     

Preliminary Research on Desulfurization of Simulated Diesel Fuel with Peroxotungstate Biquaternary Ammonium Salt/H2O2 System

Abstract

A biquaternary ammonium salt catalyst, chloride-1,4-dibenzyl-diaza-bi-cyclo [2.2.2] octane peroxotungstate (peroxotungstate biquaternary ammonium salt), was prepared, the structure of which was determined through infrared spectrometry, and was applied in desulfurization of simulated diesel fuel. Under the circumstances in which the close ion-pair of biquaternary ammonium cation and peroxotungstate anion was formed, the mechanism of phase transfer catalysis was offered with analyzing experimental process and data. The desulfurization efficiency reached 99.35% when the reaction temperature was 60°C, the reaction time was 20 min, and the molar ratio of peroxotungstate biquaternary ammonium salt to H₂O₂ was 0.015.     

Application of Microwave Technology for Desulfurization of Diesel Fuel

The microwave technology was introduced for the desulfurization of diesel fuel. The atmospheric second side-cut diesel fraction, which was supplied by Liaohe Petrochemical Company, was desulfurized by an oxidation process under microwave irradiation. Hydrogen peroxide (H202), can oxidize the sulfur compounds in diesel fuel selectively and convert them into sulfones. Based on the rule of dissolution by similar substances,these sulfones are removed from diesel fuel because they could be dissolved in solvent phase. So the sulfur content of diesel fuel is decreased. The influence of the concentration of oxidizing reagent, solvent phase to oil phase volume ratio (S/O), irradiation pressure, irradiation time, and the irradiation power have been investigated.The optimum conditions for the refining process was determined. The sulfur removal rate was 59.7% under the optimum conditions of 8%H2O2, S/O=0.25, 0.05MPa, 6 min, and 375W, respectively. When no microwave irradiation was applied, the removal rate was 11.5% only.     

超声波作用下柴油深度氧化脱硫的研究

催化氧化脱硫是降低柴油硫含量的非加氢脱硫工艺，在催化氧化溶剂抽提的基础上，引入超声波为反应提供能量，考察了超声频率、声强等因素对脱硫效果的影响。结果表明。以H2O2-有机酸为氧化剂，在室温，剂油比为0．05，搅拌速率为300r／min，反应时间为15min，频率为28kHz，声强为0．408W／cm^2的条件下进行柴油催化氧化反应，将得到的产品与萃取剂（DMF）在室温下按照1：1混合，萃取两次后进行分离，其脱硫率为94．8％，而未加超声波的脱硫率仅为67．2％，说明超声氧化脱硫效果明显优于未加超声波的氧化脱硫反应。     

Desulfurization using an oxidation/catalysis/adsorption scheme over H3PW12O40/SiO2−Al2O3 1

A desulfurization experiment was performed with tert-butyl hydroperoxide (t-BuOOH) as the oxidant in the presence of H₃PW₁₂O₄₀/SiO₂₋Al₂O₃ as the catalyst prepared by the sol-gel method, by using dibenzothiphene (DBT) in petroleum ether as the model compound. This work presents the results for the desulfurization by an oxidation/catalysis/adsorption scheme. The effects of catalyst amounts, t-BuOOH amounts, reaction temperature, and reaction time on the desulfurization efficiency and regeneration performance of the catalyst were studied. It was found that the H₃PW₁₂O₄₀/SiO₂-Al₂O₃ catalyst presented a higher maximum desulfurization conversion than SiO₂-Al₂O₃ solids also prepared by the sol-gel method. In addition, the H₃PW₁₂O₄₀/SiO₂-Al₂O₃ catalyst showed a higher desulfurization conversion after regeneration with N,N-dimethylamide. It was also found that the oxidation agent t-BuOOH resulted in a higher desulfurization conversion than hydrogen peroxide (H₂O₂). The text was submitted by the authors in English.     

COMPARISON BETWEEN THE PERFORMANCE OF CONVENTIONAL AND HIGH-METAL Co-Mo AND Ni-Mo CATALYSTS IN DEEP DESULFURIZATION OF KUWAIT ATMOSPHERIC GAS OIL

ABSTRACT

Due to environmental constraints, sulfur content of diesel fuel has been restricted to very low levels (500 ppm maximum) in many countries. As a result, a greater emphasis has been placed in recent years on the development of catalysts and processes for deep desulfurization of diesel blending streams to produce low sulfur diesel fuel. In the present work we have compared the performance of a conventional Co-Mo catalyst with that of high metal loading Co-Mo and Ni-Mo catalysts in deep desulfurization of Kuwait atmospheric gas oil. The tests were carried out in a fixed bed reactor unit using 75 ml of catalyst under the conditions: P=32 bar; LHSV = 4h^?1; H₂/oil ratio = 100 ml/ml; temperature range = 330 ? 390°C. HDS activity of the high molybdenum Co-Mo catalyst was superior to that of the conventional Co-Mo hydrotreating catalyst. High metal loading Co-Mo/Al₂O₃ catalyst also showed a substantially higher HDS activity than the Ni-Mo/Al₂O₃ catalyst containing a similar high metal loading. The unreacted sulfur compounds remaining in the product after high severity hydrotreating were identified as dibenzothiophenes with alkyl substituents next to the sulfur atom. The desulfiirization of such low reactive alkyl dibenzothiophenes was found to occur at a substantially lower temperature over the high metal loading Co-Mo catalyst compared with the conventional Co-Mo catalyst. The results have been explained on the basis of the stacking and dispersion of MoS₂ slabs as well as in terms of the nature of the sulfur vacancies in the MoS₂ layers in these catalyst systems.     

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.     

Optimization,kinetics, physicochemical and ecotoxicity studies of Fenton oxidative remediation of hydrocarbons contaminated groundwater

Fenton oxidation remediation of hydrocarbons contaminated groundwater was investigated for efficiency and effectiveness. 10% pollution was simulated in the laboratory by contaminating groundwater samples with diesel and domestic purpose kerosene (DPK) in two different experimental set ups. Optimum conditions of concentrations of the treatment solutions and pH were established: 300 mg/L (FeSO₄), 150,000 mg/L (H₂O₂) and pH = 3 for the kerosene contaminant; 100 mg/L (FeSO₄), 300,000 mg/L (H₂O₂) and pH = 3 for the diesel contaminant. The results from kinetics study show that the remediation process is pseudo-first order reaction with a rate constant of 8.07 × 10⁴ mgL^?1hr^?1 and 3.13 × 10⁴ mgL^?1hr^?1 for the diesel and kerosene contaminants in that order with 95.32% and 79.25% reduction in chemical oxygen demand (COD) for diesel and kerosene contaminated samples at the end of the remediation process respectively indicated that remediation have occurred significantly. Percent reduction in Total Petroleum Hydrocarbon (TPH) as kerosene was 89.84% and that of the diesel contaminant as 91.87% after 6 hours of remediation. The general pollution index (GPI) for the hydrocarbons contaminated samples was in the range of 6.70–7.52 against the background value of 4.39 for the control groundwater sample. After treatment the GPI had dropped to 4.13–4.43 which depicts remarkable remediation although the samples remained impaired. Therefore there is the need of post-treatments to make the groundwater fit for domestic and agricultural uses. The application of the Fenton oxidative process is found to be very efficient, effective and rapid in reducing total petroleum hydrocarbon as kerosene and diesel as target contaminants.     

复合SiO2-WO3催化剂的制备、表征及氧化脱除苯并噻吩性能

 采用溶胶-凝胶法制备了SiO₂-WO₃催化剂,并采用XRD、FT-IR、BET、TG-DTA等方法对催化剂进行表征。以苯并噻吩(BT)为模型化合物,H₂O₂为氧化剂,考察了催化剂的活性元素、制备方法、n(W)/n(Si)和焙烧温度对其催化氧化脱硫活性的影响。结果表明,W的引入降低了SiO₂的比表面积,SiO₂-WO₃催化剂中W的主物相为WO₃。在以W为活性组元,且n(W)/n(Si)为0.1时,500℃焙烧得到的SiO₂-0.1WO₃催化剂具有最好的催化脱硫活性。在模拟油20 mL、催化剂SiO₂-0.1WO₃用量0.04 g、n(H₂O₂)/n(S)为15.9、乙腈/模拟油体积比0.3、65℃反应60 min的条件下,苯并噻吩模拟油脱硫率可达99.3%。     

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.