Extraction Of Sulfur Research Articles

Desulfurization of liquid fuel via extraction with imidazole-containing deep eutectic solvent

Abstract The desulfurization of liquid fuels with deep eutectic solvent (DES) newly synthesized from inexpensive constituents of imidazole and tetrabutylammonium bromide salt was conducted via liquid-liquid extraction. The aim of the work is to lower the sulfur content of liquid fuels to below the environmental regulation using DES in a process with low energy requirement. A simulated fuel containing dibenzothiophene (DBT) and thiophene as representative refractory sulfur compounds and a commercial-grade diesel fuel were used for this work. Quantitative monitoring of sulfur compounds in the raffinate phase of the fuels was performed using high-performance liquid chromatography and energy-dispersive X-ray fluorescence techniques. The results of sulfur extraction showed that DBT and thiophene extraction efficiencies of 70% and 47%, respectively, could be achieved from the simulated fuel in a single run extraction. Similarly, 47% total sulfur removal from the commercial-grade diesel fuel was achieved with the solvent. The deep desulfurizations of the fuels were successfully achieved in four and five successive stages with the simulated fuel and the diesel fuel, respectively. The solvent was effectively regenerated after the extraction process with both fuels, thus allowing for its repetitive usage.

Experimental Investigation on Sulfur Extraction from Coal Coking Waste

During coal coking process a great deal of sulfurs are produced and are discarded to surroundings, which makes a lot of lands to be occupied and puts the environment to be polluted. In order to find multi-win production mode of coal coking for resources, surroundings and societies, carbon disulfide as an extracting agent was applied to extract sulfur from sulfur cake in this study. Final laboratory technological condition was that more than 98% sulfur yield could be gotten when the granularity of raw sulfur powder, liquid-solid ratio, extraction temperature, stirring velocity and stirring time respectively were 200 mesh, 3:1 g/g, 40°C, 200rpm and 30 min.

The Influence of Vegetation on Redistribution of Organic Substances and Chemical Elements in Technogenic Soils on Yavoriv Sulphuric Quarry Territory

Проаналізовано ґрунтово-кліматичні умови регіону досліджень. Відзначено негативний вплив збільшення площі сільськогосподарських угідь у структурі ландшафтів Надсанської низовини. Досліджено особливості порушення ґрунтів під час видобутку сірки. Оцінено роль Балтійсько-Чорноморського регіону у формуванні стабільної екологічної ситуації приток Вісли і Дністра. Проаналізовано вплив рослинних асоціацій на відтворення ґрунтів Яворівського сірчаного кар'єру. З'ясовано роль деревних порід у нагромадженні та перерозподілі органічних, хімічних елементів, показників кислотності у сформованих техноземах. Встановлено позитивну тенденцію у нагромадженні та перерозподілі гумусу, азоту та кислотності у різних прошарках ґрунту на дослідних об'єктах.

Low-Sulfur Fuel and Oil Production

Problems of transforming heavy crude high-sulfur oil into low-sulfur fuels and oils become increasingly urgent for oil refineries. The main reason for that is depletion of low-sulfur oil-fields and following rise of heavy crude oil share in world's oil production. Desulfurization of oil and petroleum residues is performed by breaking down or extraction of sulfur and sulfur compounds with catalyst and chemical additives which leads to considerable rise in price of refinery. Desulfurization technology proposed in the following research involves simultaneous use of the acoustic and hydrodynamical cavitation for breaking down long molecular connections. Oil refinery was performed in the electromechanical vortex layer activator which intensified mechanoactivation processes by intensive movement of ferromagnetic elements in the external magnetic field.

Palladium Nanoparticle Size Effect in Hydrodesulfurization of 4,6‐Dimethyldibenzothiophene (4,6‐DMDBT)

AbstractPd nanoparticle size sensitivity of 4,6‐dimethyldibenzothiophene (4,6‐DMDBT) hydrodesulfurization was investigated by using 4, 8, 13, and 87 nm particles and was compared with the sulfur‐free and sulfur‐inhibited hydrogenation of 3,3‐dimethylbiphenyl, which is a product of direct desulfurization of 4,6‐DMDBT. The smallest 4 nm particles provided unprecedented (for Pd at 5 MPa and 300 °C) direct desulfurization selectivity of 20 % at 40 % conversion because of the reduced contribution of the hydrogenation path. The 4 nm particles were poisoned by the adsorbed sulfur to the greatest extent. The optimal size, providing the highest Pd mass‐based yield of the desulfurized products, was found to be 8 nm. The catalyst with 87 nm particles was based on Pd nanocubes with the lowest edge/terrace surface atom ratio and large terraces and this showed the lowest sulfur extraction from both 4,6‐DMDBT and sulfurous intermediates as a result of the low availability of edge atoms for a perpendicular sigma‐mode adsorption through the lone pair of the sulfur atom.

Determination of 7 Indictor Polychlorinated Biphenyls (PCBs) Residues in Porphyra by Ultrasonic Extraction and Gas Chromatography (GC)

A method was developed for determination of 7 indictors the polychlorinated biphenyls (PCBs) residues in porphyra by gas chromatography (GC) with electron capture detector (ECD). The PCBs were extracted with hexane/methylene chloride (1:1, v/v) by ultrasonic extraction and the samples were cleaned up by concentrated sulfuric acid and Alumina-N solid phase extraction cartridge. The analytes were quantified by an internal standard method. Under optimal experimental conditions, good linearity was observed in the range of 5 - 200 ng/mL and the correlation coefficients were 0.9994 - 0.9998. The limit of quantitation (LOQ) for target analytes ranged from 6.0 to 10.0 μg/kg. At the spiked levels of 10, 50, 100 μg/kg, the average recoveries ranged from 90.9% to 102% with the relative standard deviations 2.12% - 6.32%. The result showed that the proposed method was rapid, and could be used for the determination of the PCBs in porphyra.

Intensification of sulfur extraction from the working solutions in the oxidative desulfurization of coke-oven gas

A deficiency of the oxidative removal of hydrocarbons from coke-oven gas is the insufficient extraction of elementary sulfur from the absorbing solution; the sulfur is formed by the oxidation of H2S. Sulfur buildup in the working solution interferes with the process and calls for periodic purification of the apparatus. To improve the extraction of sulfur from the solution, structural improvements are proposed. An inexpensive remedy is to supply surfactant so as to improve sulfur flotation. In this research, the surfactant used for wetting and flotation of the sulfur is analyzed. Classification of the reagents in terms of their hydrophilic properties is considered. Industrial samples of reagents intended to improve flotation are tested. The ascent and descent of sulfur particles in surfactant solutions is studied; the limiting wetting angle between the liquid drop and the solid surface of the sulfur particle is measured. Dynamic research on the flotation of sulfur particles by air bubbles is undertaken. The selected reagent is very effective in dynamic conditions, since the hydrophobic properties are maximized in the flotation process.

The Au-bearing vein system of the Limarinho deposit (northern Portugal): Genetic constraints from Bi-chalcogenides and Bi–Pb–Ag sulfosalts, fluid inclusions and stable isotopes

The Limarinho gold deposit (northern Portugal), located in the Variscan Iberian Massif, is a system of gold-bearing quartz veins that crosscut a peraluminous synkinematic (syn-D3: 315–310Ma) Variscan granite. The mineralized structures are subvertical and trend N30–40E parallel to the Penacova-Régua-Verín fault. The quartz veins record two main stages of mineral deposition (I and II), indicating successive periods of vein re-opening, and are crosscut by Stage-III irregular veinlets. Stage-I is characterized by milky quartz (mQ) and arsenopyrite (Apy-1), and produces a greisen-like alteration. Stage-II comprises clear quartz (cQ), K-feldspar, chlorite, rutile and metallic minerals, mainly arsenopyrite (Apy-2±Apy-3) and pyrite, with galena, chalcopyrite and sphalerite in lesser amounts. The Stage-III is characterized by chlorite and pyrite. The hydrothermal fluids in stages I and II are low salinity (<2.4wt.% NaCleq.) aqueous-carbonic, increasing the CH4+N2 amount toward the Stage-II that indicates mixing with metamorphic fluids. Temperatures of 460±40°C and pressures from 230 to 350MPa are inferred for the As–Fe mineralization of Stage-I, the highest P values indicate lithostatic conditions at a depth of around 13km. The inferred P–T conditions for the Stage-II range from 340 to 425°C and from 60 to 225MPa. A decompression of more than 250MPa through stages I to II, without a substantial cooling of around 150°C, is observed in accordance with similar Variscan belt gold deposits of Western Europe. Estimated temperatures for Stage-III are from 300°C to lower than 200°C, the pressures being around 60MPa. Late Stage-II and Stage-III are related to aqueous fluids with variable salinity as a result of a mixing between two end-members, a hotter and more saline fluid (6–7wt.% NaCleq.) and a cooler and dilute one (<2wt.% NaCleq.) probably of meteoric origin. Stable isotopic study results also indicate fluid mixing processes. Although the calculated δ18O values for aqueous carbonic fluids (10.5 to 7.6‰) do not permit to discriminate between magmatic and metamorphic, the δ18O and δD values obtained for chlorite (4.0 to 5.0‰ and −24.2 to −23.1‰, respectively) are more indicative of a meteoric signature. The δ34S values of the fluid in equilibrium with arsenopyrite range from −10.0 to −7.8‰. However, the values obtained for pyrite (around −2.6‰) can be only explained by the incorporation of an isotopically heavier sulfur from a different source, probably sedimentary. A detailed study of the ore has shown two different gold parageneses. The first (Bi–Te–(±S)) comprises native-Au, or maldonite, along with native-Bi, hedleyite and joséite-B. The second ((±Cu)Ag–Pb–Bi–S±Te) comprises electrum, (±Cu)Ag–Pb–Bi sulfosalts such as lillianite–gustavite s.s., heyrovskyite, vikingite, berryite and matildite, Pb–Bi sulfotellurides and hessite. Lamellar exsolution textures observed in the lillianite–gustavite s.s. indicate initial temperatures above 400°C. The paragenesis becomes Ag-enricher as temperature goes down. Matildite {111} exsolutions indicate a low limit of mineralization slightly above 200°C. We propose different mechanisms of gold precipitation: 1) a gold scavenged by Bi-melts in the first case; 2) remobilization of this early gold together with new gold deposition due to sulfur extraction and/or fluid mixing from the hydrothermal fluid during the stage of prevailing sulfide precipitation. We conclude that the existence of at least two gold-bearing hydrothermal events may have enhanced the gold grade in this type of gold deposits.

Contrasting mechanisms for crustal sulphur contamination of mafic magma: evidence from dyke and sill complexes from the British Palaeogene Igneous Province

The addition of crustal sulphur to magma can trigger sulphide saturation, a process fundamental to the development of some Ni–Cu–PGE deposits. In the British Palaeogene Igneous Province, mafic and ultramafic magmas intrude a thick sedimentary sequence offering opportunities to elucidate mechanisms of magma–crust interaction in a setting with heterogeneous S isotope signatures. We present S-isotopic data from sills and dykes on the Isle of Skye. Sharp contrasts exist between variably light δ 34 S in Jurassic sedimentary sulphide (−35‰ to −10‰) and a local pristine magmatic δ 34 S signature of −2.3 ± 1.5‰. Flat-lying sills have restricted δ 34 S (−5‰ to 0‰) whereas steeply dipping dykes are more variable (−0‰ to −2‰). We suggest that the mechanism by which magma is intruded exerts a fundamental control on the degree of crustal contamination by volatile elements. Turbulent flow within narrow, steep magma conduits, discordant to sediments, and developed by brittle extension or dilation have maximum contamination potential. In contrast, sill-like conduits emplaced concordantly to sediments show little contamination by crustal S. The province is prospective for Ni–Cu–PGE mineralization analogous to the sill-hosted Noril’sk deposit, and Cu/Pd ratios of sills and dykes on Skye indicate that magmas had already reached S-saturation before reaching the present exposure level. Supplementary material: Details of the whole-rock chemical sulphur extraction method; simplified geological maps of the Isle of Skye, a geological cross-section of part of southern Skye, and a stratigraphic log of the Mesoproterozoic and Mesozoic sediments of western Scotland; trace element diagrams of sills and dykes used in this study; and tables for QA/QC of S-isotope results, sample location information, and whole-rock major and trace element results for sill and dyke samples and for Jurassic mudrocks are available at http://www.geolsoc.org.uk/SUP18834 .

Sulfuric Acid Assisted Extraction and Fractionation of Porphyrins From Heavy Petroleum Residuals With a High Content of Vanadium and Nickel

Primary porphyrin extracts were obtained from carbon tetrarchloride solutions of different heavy oil residuals with assistance of sulfuric acid. According to data of chromatographic separation of extracts porphyrinic fractions appear in amount of 13.0–24.2%. Based on UV/visible absorption spectroscopy the presence of porphyrins of etio and phyllo types mostly with rhodo and deoxophylloerythroetioporphyrins in lower amount was established. The content of porphyrins in obtained fractions was determined at the level of 15.3–44.8% of the total weight. It was shown that a higher concentration of porphyrins in sulfuric acid extracts occurs for the case of the high vanadium and nickel content and low amounts relation of asphaltenes to resins.

Influence of various stabilizing factors on an elemental sulfur emulsion during high-temperature leaching of nickel-pyrrhotine concentrates

It is shown that the problems of decomposition of the three-phase sulfur emulsions that form during hydrothermal oxidation of pyrrhotine and the choice of conditions of their stabilization represent one of the main problems of the theory and practice of the pressure oxidizing leaching (POL) of nickel-pyrrhotine concentrates (NPCs) carried out at high temperatures. The character and the degree of influence of a number of stabilizing factors (mixing intensity, consumption of commercial lignosulphonates (LSNs), amount of added gangue) on the particle size distribution of elemental sulfur during POL of NPCs, which have different contents of the main components, are studied. Mathematical statistics is used to derive regression equations and response surfaces to describe the dependence of the extraction of elemental sulfur into hard-to-float particle size classes (−10 µm, +150 µm) on the factors under study. It is found that the key factor that determines the particle size distribution of elemental sulfur is the consumption of LSN surfactants during high-temperature leaching of NPCs irrespective of the chemical-mineralogical composition. A pronounced synergetic effect of a positive influence of LSN and a rock-containing addition is experimentally detected during leaching of high-sulfur NPC.

Phase purification of Cu–S system towards Cu1.8S and its catalytic properties for a clock reaction

TPP can be used for the phase-selective extraction of sulfur from sulfur-rich copper sulfides. The clock reaction catalyzed by Cu–S based product has been demonstrated.

Polar nitrogen-containing aromatic compounds as carriers of natural diesel lubricity

Hydrodesulfurization (HDS) reduces the original lubricity of diesel fuel on which fuel injection equipments (FIE) rely for proper operation and lifetime. In technical terms this problem was solved by addition of lubricity additives to low and ultra-low sulfur diesel. In scientific terms there is no clear final conclusion on the role of neither sulfur- nor polar oxygen- and nitrogen-containing compounds. In this study, polar compounds were extracted from a gas oil by an ionic liquid so that the fuel was not saturated by hydrogen like in the industrial HDS process. Stepwise extraction and measurement of sulfur and nitrogen contents as well as lubricity revealed a significant correlation between lubricity and nitrogen content. For investigation on the molecular structure of the lubricating nitrogen compound, selected model compounds with different structural features were added to an ultra-low sulfur diesel (ULSD). The results indicate that the combination of a diaromatic base structure with a polar substituent and a nitrogen heteroatom exhibits excellent lubricity improvement superior to those structures lacking one or more of these three properties. A three-stage tribological model for the boundary lubrication by such compounds is proposed in this paper. These compounds are identified as the main carrier of original diesel lubricity which are removed by the industrial HDS process.

Improvement of closed-cycle sulfur recovery from coke-oven gas

Improvement in the closed-cycle technology for sulfur removal from coke-oven gas used in the by-product shop of the coke plant at OAO Magnitogorskii Metallurgicheskii Kombinat is considered, with a view to more effective sulfur extraction and lower capital costs. The efficiency of hydrogen-sulfide conversion in the system for sulfur recovery at OAO MMK is such that additional catalytic conversion is unnecessary. To identify the most active catalyst for single-stage conversion of sulfur-bearing gases, monitoring data for the industrial reactor in the sulfur-production department in the Polar Division Copper Plant of MMC Norilsk Nickel are analyzed. Of the four catalysts tested, the most effective is AOK-78-59 aluminum-oxide catalyst, produced by OOO Katalizator (Novosibirsk).

A single-step microwave-assisted acid extraction of total sulphur in coal samples followed by ICP-OES determination

A rapid microwave-assisted acid extraction (MW-AAE) procedure using a dilute [HNO3–H2O2] mixture followed by inductively coupled plasma optical emission spectroscopy (ICP-OES) analysis has been developed for the determination of total sulphur in coal samples. Parameters affecting the MW-AAE such as extractant concentration, microwave temperature, extraction time, coal amount and HNO3 : H2O2 volume ratio were optimized by using a certified reference material (SARM 20) in order to attain total sulphur quantitative recoveries. The optimum conditions for the extraction procedure were found to be 180 °C, 5 min, 3 mol L−1, 3 mol L−1, 0.05 g and 2 : 1 for microwave temperature, extraction time, [HNO3], [H2O2], coal amount and HNO3 : H2O2 volume ratio, respectively. Under optimum conditions, the accuracy of the MW-AAE method was examined by analyzing three coal certified reference materials (SARM 18, 19 and 20) and quantitative recoveries (83–102%) were achieved. Additionally, the precision of the proposed method, expressed in terms of relative standard deviation (n = 15), was satisfactory (≤3%). The method limit of detection (0.026 μg g−1) and method limit of quantification (0.087 μg g−1) for sulphur analysis were relatively good as compared to work reported in the literature.

Converting Ag₂S-CdS and Ag₂S-ZnS into Ag-CdS and Ag-ZnS nanoheterostructures by selective extraction of sulfur.

A mild three-step solution strategy is developed to prepare Ag-MS (M=Zn, Cd) nanoheterostructures composed of MS nanorods with silver tips. First, Ag2S-MS heterostructures are synthesized by following a solution-liquid-solid mechanism with Ag2S nanoparticles as catalysts, then the Ag2S sections of the heterostructures are converted into silver nanoparticles by selective extraction of sulfur. Notably, for the prepared Ag-CdS heterostructures, the localized surface plasmon resonance of silver remarkably intensifies the photoluminescence of CdS by enhancing the excitation light absorption, which is beneficial for potential applications of CdS nanoparticles in the fields of biolabeling, light-emitting diodes, and so forth. The strategy reported herein would be useful for designing and fabricating other metal-semiconductor hybrid nanostructures with desirable performances.

Teores de minerais em polpas e cascas de frutos de cultivares de bananeira

O objetivo deste trabalho foi determinar a percentagem de matéria seca, o teor de minerais e a capacidade de fornecimento de minerais, com base na ingestão dietética de referência na polpa e na casca de frutos verdes e maduros de 15 cultivares de bananeira. Utilizaram-se quatro cachos por cultivar e seis frutos por unidade amostral. Foram coletadas amostras frescas da polpa e da casca, para digestões sulfúricas (0,2 g) e nitroperclóricas (0,5 g). Foram determinados: no extrato sulfúrico, o N total pelo método Kjeldahl; e, no extrato nitroperclórico, P, K, Ca, Mg, Cu, Mn, Fe, Zn e Se. O P foi determinado por colorimetria, e os demais nutrientes, por espectrofotometria de absorção atômica. O teor de minerais na polpa e na casca foi expresso com base na média dos dois estádios. Há diferenças entre cultivares de bananeira quanto à concentração de macro e micronutrientes na polpa e na casca, mas não entre frutos verdes e maduros. A cultivar Terrinha apresentou a maior percentagem de matéria seca na polpa, e as cultivares Marmelo e Maçã, na casca. Para N, P, Fe, Zn e Cu, a casca apresentou duas vezes o teor da polpa. O teor de K e Mn na casca foi de aproximadamente quatro vezes o da polpa. A polpa da cultivar Caipira (AAA) e a casca das cultivares Prata e Pacovan (AAB) apresentam os maiores teores de minerais.

Modern applications for a total sulfur reduction distillation method - what's old is new again.

BackgroundThe use of a boiling mixture of hydriodic acid, hypophosphorous acid, and hydrochloric acid to reduce any variety of sulfur compounds has been in use in various applications since the first appearance of this method in the literature in the 1920’s. In the realm of sulfur geochemistry, this method remains a useful, but under-utilized technique. Presented here is a detailed description of the distillation set-up and procedure, as well as an overview of potential applications of this method for marine sulfur biogeochemistry/isotope studies. The presented applications include the sulfur isotope analysis of extremely low amounts of sulfate from saline water, the conversion of radiolabeled sulfate into sulfide, the extraction of refractory sulfur from marine sediments, and the use of this method to assess sulfur cycling in Aarhus Bay sediments.ResultsThe STrongly Reducing hydrIodic/hypoPhosphorous/hydrochloric acid (STRIP) reagent is capable of rapidly reducing a wide range of sulfur compounds, including the most oxidized form, sulfate, to hydrogen sulfide. Conversion of as little as approximately 5 micromole sulfate is possible, with a sulfur isotope composition reproducibility of 0.3 permil.ConclusionsAlthough developed many decades ago, this distillation method remains relevant for many modern applications. The STRIP distillation quickly and quantitatively converts sulfur compounds to hydrogen sulfide which can be readily collected in a silver nitrate trap for further use. An application of this method to a study of sulfur cycling in Aarhus Bay demonstrates that we account for all of the sulfur compounds in pore-water, effectively closing the mass balance of sulfur cycling.

Production of Liquid Fuel by Catalytic Reformation of Carbohydrates in Energy Crops

Gamma-valerolactone (GVL) represents a promising future source for both fuel alternatives and renewable materials. It can be formed from the hydrogenation of levulinic acid (LA). However, when lower cost unprocessed biomass is utilized to form levulinic and formic acid, other organic compounds are created, primarily from the hemicelluloses portion. Therefore a two-stage conversion process was designed starting with a mild acid extraction to remove the majority of the pentoses while maintaining the hexose sugars in a solid form utilizing previously described optimized conditions. Mild sulfuric acid extraction experiments on hybrid poplar samples were performed and optimized. The resulting hexosan enriched biomass was then subjected to a series of experiments employing high sulfuric acid and temperature to form LA and FA with yield of over 60% achieved. Finally, the LA and FA were catalytically converted to GVL, which could be purified through solvent extraction with nearly 100% conversion achieved.

Possibility of using biodiesel from sunflower oil as an additive for the improvement of lubrication properties of low-sulfur diesel fuel

Harsh requirements regarding the exhaust gases emission have conditioned the development of new systems in the engine, as well as the development of ecological fuels. Sulfur extraction considerably impairs the lubrication properties of diesel fuel. This has consequences in the rapid wear of the elements that constitute the fuel injection system. Additives for the improvement of lubrication properties are added with the aim of eliminating the adverse effect of fuel. The problem related to the use of those additives lies in the fact that they contain heavy aromatic solvents such as methyl naphthalene, methyl naphthalene and biphenyl which are harmful to health. Therefore, the aim of this research is to determine whether there is a possibility to use biodiesel for the improvement of lubrication properties of fossil diesel with low sulfur content instead of standard additives.In this research biodiesel obtained from sunflower oil was blended with fossil diesel which did not have additionally added additives for the improvement of lubrication properties. The obtained results were compared with the other researches on the use of fossil diesel with added standard additives. The blends of fossil diesel and biodiesel content of 1–7% v v−1 were used here. The experimental research used different test fuels for the testing of chemical and lubrication properties of fuel, tractor engine performance and exhaust gas emissions.By adding biodiesel, fossil diesel properties remained within the limits set by the standard EN 590 while lubrication properties were significantly improved. On the other hand, power of tractor engine did not change significantly. Although biodiesel had lower heating value with respect to fossil diesel, blending 5, 6 and 7% v v−1 of biodiesel caused slight increase in the engine power. Tests of exhaust gas emissions indicated that the addition of biodiesel reduced the content of CO2 and CO. The problems related to the use of biodiesel as an additive can be reduced by oxidation fuel stability, increased specific fuel consumption, reduced thermal efficiency and increased NOx emission.