Ultrasound-assisted Oxidative Desulfurization Research Articles

Sulfur removal from hydrotreated petroleum fractions using ultrasound-assisted oxidative desulfurization process

Ultrasound-assisted oxidative desulfurization (UAOD) process was applied to diesel oil and petroleum product feedstock containing model sulfur compounds (benzothiophene, dibenzothiophene and dimethyldibenzothiophene). The influence of oxidant amount, volume of solvent for the extraction step and time and temperature of ultrasound treatment (20kHz, 750W, operating at 40%) was investigated. Using the optimized conditions for UAOD, sulfur removal up to 99% was achieved for model compounds in petroleum product feedstock using a molar proportion for H2O2:acetic acid:sulfur of 64:300:1, after 9min of ultrasound treatment at 90°C, followed by extraction with methanol (optimized solvent and oil ratio of 0.36). Using the same reagent amount and 9min of ultrasound the removal of sulfur was higher than 75% for diesel oil samples. Sulfur removal without ultrasound using the same conditions was lower than 82% for model compounds and 55% for diesel oil samples showing that ultrasound improved the efficiency of oxidative desulfurization. In comparison to conventional hydrodesulfurization, the proposed UAOD process can be performed under relatively mild conditions (atmospheric pressure and 90°C, without using metallic catalysts).

The study of ultrasound-assisted oxidative desulfurization process applied to the utilization of pyrolysis oil from waste tires

In recent years, the increasing world population and rapid industrial development has increased the consumption of fossil fuel-derived oils. In response to the resulting exhaustion of fossil fuel energy, many countries around the world are investigating methods of waste energy recovery and reuse, including oil recovery from the pyrolysis process of waste tires. This study investigates the efficiency of an ultrasound-assisted oxidative desulfurization (UAOD) process in sulfur reduction from diesel oil and the pyrolysis oil from waste tires treatment. The results indicate that the oxidation efficiency increases as the doses of transition metal catalyst are increased. Longer sonication time also enhances the oxidation process, apparently through the biphasic transfer of oxidants, which results in a high yield of organic sulfur oxidation products. The best desulfurization efficiency was 99.7% (2.67 ppm sulfur remaining) and 89% (800 ppm sulfur remaining) for diesel and pyrolysis oils, respectively, via a process executed by two UAOD units connected in series and combined with solid adsorption using 30 g of Al 2O 3 in 6 cm columns. These batch experiment results demonstrate clean waste energy recovery and utilization, while fulfilling the requirements of Taiwan EPA environmental regulations (sulfur concentrations less than 5000 ppm).

Ultrasound-assisted oxidative desulfurization of liquid fuels and its industrial application

Latest environmental regulations require a very deep desulfurization to meet the ultra-low sulfur diesel (ULSD, 15 ppm sulfur) specifications. Due to the disadvantages of hydrotreating technology on the slashing production conditions, costs and safety as well as environmental protection, the ultrasound-assisted oxidative desulfurization (UAOD) as an alternative technology has been developed. UAOD process selectively oxidizes sulfur in common thiophenes in diesel to sulfoxides and sulfones which can be removed via selective adsorption or extractant. SulphCo has successfully used a 5000 barrel/day mobile “Sonocracking” unit to duplicate on a commercial scale its proprietary process that applies ultrasonics at relatively low temperatures and pressures. The UAOD technology estimate capital costs less than half the cost of a new high-pressure hydrotreater. The physical and chemical mechanisms of UAOD process are illustrated, and the effective factors, such as ultrasonic frequency and power, oxidants, catalysts, phase-transfer agent, extractant and adsorbent, on reaction kinetics and product recovery are discussed in this review.

Ultrasound-assisted oxidative process for sulfur removal from petroleum product feedstock

A procedure using ultrasonic irradiation is proposed for sulfur removal of a petroleum product feedstock. The procedure involves the combination of a peroxyacid and ultrasound-assisted treatment in order to comply with the required sulfur content recommended by the current regulations for fuels. The ultrasound-assisted oxidative desulfurization (UAOD) process was applied to a petroleum product feedstock using dibenzothiophene as a model sulfur compound. The influence of ultrasonic irradiation time, oxidizing reagents amount, kind of solvent for the extraction step and kind of organic acid were investigated. The use of ultrasonic irradiation allowed higher efficiency for sulfur removal in comparison to experiments performed without its application, under the same reactional conditions. Using the optimized conditions for UAOD, the sulfur removal was about 95% after 9 min of ultrasonic irradiation (20 kHz, 750 W, run at 40%), using hydrogen peroxide and acetic acid, followed by extraction with methanol.

Superoxides: Alternative Oxidants for the Oxidative Desulfurization Process

Superoxides, for instance, potassium superoxide, have been demonstrated as alternative oxidants for the oxidative desulfurization process. For model compounds of benzothiophene, dibenzothiophene, and a number of selected diesel oil samples, sulfur removal greater than 90% and as high as 99% was accomplished. The results for using this solid potassium superoxide are comparable to or better than the results with liquid hydrogen peroxide for the ultrasound-assisted oxidative desulfurization (UAOD) or oxidative desulfurization (ODS) process. This solid oxidant can highly reduce the weight of oxidant dose, reactor volume, storage, and transport/shipment requirements. For the first time, the feasibility of desulfurization for high sulfur containing heavy oil with sulfur content greater than 1% has been demonstrated.

Portable Continuous Ultrasound-Assisted Oxidative Desulfurization Unit for Marine Gas Oil

A tailor-made module reactor, the sonoreactor, was successfully assembled to demonstrate the oxidative desulfurization of petroleum oil. This is a unique unit constructed specifically for assisting petroleum industries. Therefore, on the basis of the concept of module design, the portable unit of continuous flow system, which consists of a sonoreactor, a RF amplifier, a function generator, a pretreatment tank, and a pipeline system, was operated at ambient temperature and pressure for a given time. For the best quality or quantity purposes and performance, multiple sonoreactors can be scaled up to connect in series or in parallel, respectively. This portable unit of continuous flow system has demonstrated the feasibility of large-scale operation even in a relatively small installation area with low capital investment and maintenance cost. It also ensures the safety considerations by operating under ambient temperature and pressure and permits a multistage process for the best quality or quantity purposes ...

Surface characterization of adsorbents in ultrasound-assisted oxidative desulfurization process of fossil fuels

Surface properties of two different phases of alumina were studied through SEM images. Characterization of amorphous acidic alumina and crystalline boehmite by XRD explains the differences in adsorption capacities of each sample. Data from small angle neutron scattering (SANS) provide further results regarding the ordering in amorphous and crystalline samples of alumina. Quantitative measurements from SANS are used for pore size calculations. Higher disorder provides more topological traps, irregularities, and hidden grooves for higher adsorption capacity. An isotherm model was derived for adsorption of dibenzothiophene sulfone (DBTO) by amorphous acidic alumina to predict and calculate the adsorption of sulfur compounds. The Langmuir–Freundlich model covers a wide range of sulfur concentrations. Experiments prove that amorphous acidic alumina is the adsorbent of choice for selective adsorption in the ultrasound-assisted oxidative desulfurization (UAOD) process to produce ultra-low-sulfur fuel (ULSF).

Selective Adsorption in Ultrasound-Assisted Oxidative Desulfurization Process for Fuel Cell Reformer Applications

Alumina has been used as a selective solid adsorbent for a scaleup test of a jet fuel and diesel fuel desulfurization technique. The oxidative process with ultrasound assistance has been improved f...

Aspects of Selective Adsorption among Oxidized Sulfur Compounds in Fossil Fuels

Solid adsorbents were tested for adsorbing oxidized sulfur compounds to identify a selective adsorbent for completion of an oxidative process that was enhanced by ultrasound irradiation. Therefore, the advantages of both oxidative and adsorptive desulfurization have been put together for an upgraded system. Gas chromatograms from a gas chromatograph-sulfur chemiluminescence detector (GC-SCD) evaluate the efficiency and selectivity of different adsorbents on different model sulfur compounds. As a single adsorbent, acidic alumina adsorbs 5.7 mg sulfur/g of alumina from an oxidized refractory sulfur compound. Acidic alumina is capable of maintaining its capacity at more than 98% after calcining for regeneration. Adsorption studies were carried out to find the effect of particle size and surface area along with the pore size of each adsorbent. Acidic alumina shows promising results as an adsorbent in the ultrasound-assisted oxidative desulfurization (UAOD) process to achieve ultralow sulfur fuel (ULSF).

Enhance efficiency of tetraoctylammonium fluoride applied to ultrasound-assisted oxidative desulfurization (UAOD) process

The ultrasound-assisted oxidative desulfurization (UAOD) process has been applied to a number of diesel fuels containing varying amounts of sulfur content. The transition metal complex and quaternary ammonium salts (QAS) phase transfer agents have been applied with aqueous hydrogen peroxide as oxidizing agent. High yield of 3-bromobenzothiophene, and 2-bromobenzothiphene sulfone has been found from phase transfer agents containing tetraoctylammonium bromide. No contaminates such as bromo compound derivates had been isolated when the new fluoride phase transfer agent was used. Selectivity was particularly high for this process as demonstrated by selective ions mass spectrometry. The experiment also demonstrated that the catalyst could be recovered for reuse. Furthermore, the hydrogen peroxide provides a good performance, and the oxidation will proceed as low as 0.25%.

03/01653 A new method for obtaining ultra-low sulfur diesel fuel via ultrasound assisted oxidative desulfurization: Mei, H. et al. Fuel, 2003, 82, (4), 405–414

03/01653 A new method for obtaining ultra-low sulfur diesel fuel via ultrasound assisted oxidative desulfurization: Mei, H. et al. Fuel, 2003, 82, (4), 405–414

A new method for obtaining ultra-low sulfur diesel fuel via ultrasound assisted oxidative desulfurization☆

Due to the requirement of stringent rules for ultra-low sulfur content of diesel fuels, it is necessary to develop alternative methods for desulfurization of fossil fuel derived oil. Using appropriate oxidants and catalysts with the assistance of ultrasound irradiation, model compounds such as dibenzothiophene can be quantitatively oxidized in minutes. For diesel fuels containing various levels of sulfur content, and through the use of catalytic oxidation and ultrasonication followed by solvent extraction, removal efficiency of sulfur-bearing compounds can reach or exceed 99% in a short contact time at ambient temperature and atmospheric pressure. This simple approach can be the basis for obtaining ultra-low sulfur-containing diesel oil. GC-PFPD, GC–MS, and GC-SIMDIS were used to monitor the change of organic sulfur compounds and hydrocarbons in diesels during the process.

Successful high dose intravenous immunoglobulins (IVIG) treatment in recurrent autoimmune or alloimmune spontaneous abortion : De Carolis C., Vaquero E., Miriello D., Ruggiero G., Valensise H., Perricone R., Fontana L., Romanini C. Immunologica Clinica ed Allergologia, University of Rome Tor Vergata, P. le Umanesimo 10, I-00144 Rome, Italy [International Journal of Immunopathology and Pharmacology 10(2), 125–131; 1997

Oxidative desulfurization (ODS) was applied to three marine fuels with viscosities between 380 and 700 cSt (centistokes) and sulfur contents between 0.79 and 3.27 wt.%, using a MoO3/Al2O3 catalyst. H2O2 was chosen as oxidizing agent with a low oxidant to sulfur ratio of 3, for economic and environmental reasons. Global sulfur removal was obtained after extraction of sulfones by dimethylformamide. Oxidation efficiency was evaluated by monitoring the conversion of alkyl-benzothiophenes and dibenzothiophene molecule by gas chromatography (GC) with a sulfur specific detector. Applying ultrasounds prior to oxidation was found to significantly enhance conversions and sulfur removal, the effect being more pronounced when initial efficiency was low, that is for more refractory molecules and heavier fuels. Ultrasound assisted ODS (UAOD) was effective on raw fuels with initial viscosity below 700 cSt. Indeed, dilution decreased the viscosity of the fuels, allowing reaction to be effective even on initially very heavy fuels. The presence of asphaltenes dissolved or precipitated in the feed did not affect the conversion of Cx-BTs and DBT significantly, with only slight variations of global sulfur removal rates. Global desulfurization rates between 60 and 80 % were obtained, clearly showing the efficiency of UAOD applied to complex matrices such as marine fuels.