Sulfur Diesel Research Articles

Comparative cardiopulmonary toxicity of exhausts from soy-based biofuels and diesel in healthy and hypertensive rats

Increased use of renewable energy sources raise concerns about health effects of new emissions. We analyzed relative cardiopulmonary health effects of exhausts from (1) 100% soy biofuel (B100), (2) 20% soy biofuel + 80% low sulfur petroleum diesel (B20), and (3) 100% petroleum diesel (B0) in rats. Normotensive Wistar–Kyoto (WKY) and spontaneously hypertensive rats were exposed to these three exhausts at 0, 50, 150 and 500 μg/m3, 4 h/day for 2 days or 4 weeks (5 days/week). In addition, WKY rats were exposed for 1 day and responses were analyzed 0 h, 1 day or 4 days later for time-course assessment. Hematological parameters, in vitro platelet aggregation, bronchoalveolar lavage fluid (BALF) markers of pulmonary injury and inflammation, ex vivo aortic ring constriction, heart and aorta mRNA markers of vasoconstriction, thrombosis and atherogenesis were analyzed. The presence of pigmented macrophages in the lung alveoli was clearly evident with all three exhausts without apparent pathology. Overall, exposure to all three exhausts produced only modest effects in most endpoints analyzed in both strains. BALF γ-glutamyl transferase (GGT) activity was the most consistent marker and was increased in both strains, primarily with B0 (B0 > B100 > B20). This increase was associated with only modest increases in BALF neutrophils. Small and very acute increases occurred in aorta mRNA markers of vasoconstriction and thrombosis with B100 but not B0 in WKY rats. Our comparative evaluations show modest cardiovascular and pulmonary effects at low concentrations of all exhausts: B0 causing more pulmonary injury and B100 more acute vascular effects. BALF GGT activity could serve as a sensitive biomarker of inhaled pollutants.

Ultrasound assisted oxidative desulfurization of model diesel fuel

Very stringent environmental regulations have limited the level of sulfur in diesel, therefore deep desulfurization of fuels is required. For that purpose, the frequently used industrial process is hydrodesulfurization (HDS) which enables effective elimination of sulfur compounds such as mercaptanes, thiols, sulfides, disulfides from diesel oil, but removal of thiophene sulfur compounds (benzothiophene, dibenzothiophene, 4,6 dimethyldibenzothiophene) is insufficient. Ultrasound assisted oxidative desulfurization (UAOD) as one of several new technologies enables performance under mild conditions without use of explosive hydrogen. A higher reactivity of thiophene sulfur compounds during UAOD also provides conversion into highly polar sulfoxides and sulfones that are easily removed by adsorption or extraction. Nowadays, different catalyst/oxidants systems are being studied to improve oxidation reaction efficiency and enhance the mass transfer in the interfacial region. In this paper, the effect of reaction temperature (40–70°C) and oxidation time (5–150min) for UAOD of model diesel fuel with a catalyst/oxidants system (acetic acid/hydrogen peroxide) was investigated in a 70ml batch reactor. Furthermore, the effects of different initial concentrations of dibenzothiophene (DBT) and of ultrasound amplitude were additionally examined to achieve efficient sulfur removal. The obtained results indicated that temperature and US amplitude of 70°C and 80% respectively were efficient for conversion of DBT (sulfur concentration up to 3976.86ppm). The results indicate a rise in the yield of sulfones at higher temperatures and subsequent extraction with N,N-dimethylformamide conducted after the process of oxidation at different solvent/oil ratio revealed sulfur removal efficiency of 98.35%.

Optimization of extractive desulfurization of Malaysian diesel fuel using response surface methodology/Box–Behnken design

Systematic experiments were conducted to investigate the most appropriate extraction conditions for sulfur reduction. Initial extraction studies showed that DMF was the most potentially effective solvent. The influence of DMF to diesel ratios, extraction times and temperatures, addition of co-solvent, solvent mixtures, double extractions were explored. The use of co-solvent and solvent mixtures showed poor efficiencies of sulfur removal. A two-stage extraction with ratio of 1:1 (DMF/Diesel) was successfully removed over 88.0% of sulfur in diesel. Under Box–Behnken design, the model showed that maximum extraction ability was observed at 30°C, 30min and 1.0 of DMF/diesel ratio to achieved 67.5%.

Investigation of chemical modifiers for sulfur determination in diesel fuel samples by high-resolution continuum source graphite furnace molecular absorption spectrometry using direct analysis

High-resolution continuum source graphite furnace molecular absorption spectrometry has been applied for sulfur determination in diesel fuel. The sharp rotational lines of the carbon monosulfide molecule (formed during the vaporization step) were used to measure the absorbance. The analytical line at 258.056nm was monitored using the sum of three pixels. Different chemical modifiers were investigated and the mixture of palladium and magnesium was used as chemical modifier in combination with iridium as permanent modifier. l-Cysteine was chosen as sulfur standard and the calibration was done against aqueous standard solutions. The proposed method was applied for the analyses of four diesel samples: two S10 samples and two S500 samples. The trueness of the method was checked with a certified reference material (CRM) of sulfur in diesel fuel (NIST 2724b). Accurate results, for samples and CRM, were achieved after a dilution with propan-1-ol. The following figures of merit were obtained: characteristic mass of 17±3ng, limit of detection and limit of quantification of 1.4mgkg−1 and 4.7mgkg−1, respectively.

Catalytic oxidative desulfurization of diesel fuel utilizing a polymolybdate alumina supported catalyst: characterization, catalytic activity and mechanistic study

The performance of oxidative desulfurization of commercial diesel by alumina supported polymolybdate based catalyst system was studied using tert-butyl hydroperoxide (TBHP) as an oxidizing agent. Transition metals such as Fe, Co and Cu were introduced onto the surface of alumina, prior to the impregnation of MoO3. The results showed that the oxidation of sulfur in commercial diesel with TBHP decreased in the order: Fe/MoO3/Al2O3 > Co/MoO3/Al2O3 > Cu/MoO3/Al2O3. Further investigations on doped molybdenum revealed that Fe/MoO3/Al2O3, calcined at 500 °C was the best catalyst in this study. The catalyst was able to reduce sulfur levels in commercial diesel from 440 ppmw to less than 18 ppmw. In addition, 96 % of total sulfur was removed after a second extraction. Based on our results, the reaction mechanisms for oxidation of sulfur compound, in the presence of Fe/MoO3/Al2O3 catalyst, to the corresponding sulfones may be suggested.

Petroleum and diesel sulfur degradation under gamma radiation

Abstract Hydrodesulfurization (HDS) is currently the most common method used by refineries to remove sulfur compounds from petroleum fractions. However, it is not highly effective for removing thiophene compounds such as benzothiophene. Additionally, this process generates high costs for the oil industry. In the present work, ionizing radiation was used in order to study the effect on the degradation of petroleum and diesel sulfur compounds. Crude oil and diesel fuel samples were studied, without any pretreatment, and irradiated using a cobalt-60 gamma cell in a batch system at absorbed doses of 30 kGy and 50 kGy. The sulfur compounds were extracted and then analyzed by gas chromatography associated with mass spectrometry (GCMS). A high efficiency of ionizing radiation was observed regarding the degradation of sulfur compounds such as benzothiophene and benzenethiol and the formation of fragments, for example 1.2-dimethylbenzene and toluene.

Effect of desulfurization of diesel and its blends with biodiesel on metallic contact

The current environmental scenario has required changes in fuel nature, in order to minimize the harmful effects caused by sulfur in diesel. However, reductions in sulfur content promote loss of its lubricity and consequently wear in the injection system of the diesel engine. This study aimed to investigate the influence of sulfur minimization on fuel lubricity and wear of metallic disks. The fuel tribological analysis was carried out in HFRR equipment in accordance with ASTM D 6079 - 04. The tested fuels were diesel oil with 50, 500 and 1800 ppm sulfur, and their blends of soybean and sunflower biodiesel (5, 20 and 100% in volume). The results showed an increase of disks wear with reduction of sulfur content when lubricated with pure diesel. This fact was decreased when biodiesel was added to all concentrations.

Determination of sulfur in diesel via CS molecule by high-resolution molecular absorption spectrometry applying palladium nanoparticles as chemical modifier

Crude oil contains a high concentration of sulfur, an element that poses serious environmental and health risks. Sulfur occurs mostly in heavier petroleum fractions, like diesel, and it is possible to reduce its concentration by using methods such as catalytic hydrodesulfurization. High-resolution continuum source molecular absorption spectrometry (HR-CS MAS) allows for determination of non-metals. Sulfur is generally analyzed as the CS molecule at 258 nm, which corresponds to the electronic transition X1Σ+ → A1Π. This study aimed to apply graphite furnace HR-CS MAS to determine sulfur in diesel, using palladium nanoparticles as chemical modifier. To evaluate the proposed method, seven diesel samples (including two reference samples) were employed as emulsions with surfactants and alcohols. Direct diesel analysis was also evaluated, in an attempt to improve sulfur detection. Sodium sulfate, thiourea, and 2-mercaptoethanol were used as sulfur standards. Two types of synthesized palladium nanoparticles were compared with other chemical modifiers in graphite furnace vaporization. Measurements were conducted at 258.056 nm, with detection of three pixels. The ethanol emulsion was stable (4 h). PdCl2 nanoparticles provided the best results as chemical modifier, and thiourea was the most suitable sulfur standard under the experimental conditions. The following figures of merit were obtained: limit of detection (LOD) = 120 mg kg−1, limit of quantification (LOQ) = 400 mg kg−1, R2 = 0.9972, and relative standard deviation = 1–5%. The method's accuracy, evaluated with two reference samples, agreed with a confidence interval of 95%. It was not possible to determine sulfur in one sample only (sulfur concentration 10 mg kg−1), due to the LOD. This drawback was circumvented by applying direct diesel analysis. Using Pd nanoparticles as chemical modifier it was possible to obtain better sensitivity, LOD (7.2 ng absolute or 3 mg kg−1 for direct analysis), and LOQ (24 ng or 9 mg kg−1).

Oxidative desulfurization of commercial diesel catalyzed by tert-butyl hydroperoxide polymolybdate on alumina: optimization by Box-Behnken design

In this paper, the performance of oxidative desulfurization of commercial diesel by alumina-supported polymolybdate-based catalyst system was studied. The oxidizing reagent used was tert-butyl hydroperoxide. The catalyst was prepared using wet impregnation method and characterized by FESEM-EDX and X-ray photoelectron spectroscopy. The effects of dopants, catalyst loading, dopant loading, and calcination temperature of the catalyst were investigated. Further investigations on doped molybdenum revealed that Fe–MoO3/Al2O3 catalyst calcined at 500 °C with 10 % of Fe loading and 9 g/L, the catalyst was able to reduce the sulfur in commercial diesel from 440 to 88 ppmw. Response surface methodology involving Box-Behnken was employed to evaluate and optimize Fe–MoO3/Al2O3 preparation parameters (calcinations temperature, catalyst loading, and Fe loading) and their optimum values were found to be 550 °C, 10 g/L and 10 % of calcination temperature, catalyst loading, and Fe loading.

Electrochemical Determination of Organic Compounds in Automotive Fuels

AbstractThis article critically reviews the electroanalytical methods devoted for the determination of organic compounds in automotive fuels that can range from contaminants to additives typically introduced into liquid biofuels and liquid fossil fuels. Contaminants such as aldehydes and ketones in bioethanol, free fatty acids and glycerol in biodiesel, and sulfur and nitrogen organic compounds in gasoline and diesel fuel, and additives such as colour markers and antioxidants added to fuels were determined by electroanalytical methods. Special focus is given to electrodes, electrochemical techniques, and sample preparation strategies. Future directions of research on electroanalysis of liquid fuels are presented.

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.

Quantitative Analysis of Sulfur in Diesel by Enzymatic Oxidation, Steady-State Fluorescence, and Linear Regression Analysis

International environmental regulations have created the need for sensitive, accurate, and reproducible analytical tools to measure ultralow sulfur concentrations in fuels, such as diesel and gasoline. In this work, a sensitive, accurate, and reproducible analytical methodology to measure ultralow sulfur concentrations in desulfurized diesels (<0.01 ppb) is presented. The spectroscopic technique used here overcomes the lack of selectivity or signal overlapping that is present in other techniques used nowadays. The methodology consists first of an enzymatic partial oxidation of sulfur compounds of diesel, followed by the selective determination of the sulfur content from the emission spectra of the oxidized diesel using simple regression analysis. As a result of the enzymatic oxidation, we report here that the oxidized diesel exhibits different spectroscopic behaviors, where the oxidized organic sulfur compounds present a characteristic emission band at higher wavelengths. This fact is taken in this study for a selective quantification of sulfur from diesel. Our study is focused on 4,6-dimethyldibenzothiophene (DMDBT) as a model and standard compound for predicting the sulfur content in desulfurized diesel. The correlation coefficient (R2) between predicted and real sulfur contents was 0.95.

Study on Adsorption Property of Different Adsorbents for Dibenzothiophenic Sulfur in Simulated Diesel

It’s more difficult to remove dibenzothiophenic sulfur in diesel. Adsorption performance of self-made metal-organic framework on Cu-BTC, MCM-22, alumina and silica gel for 4-methyldibenzothiophene (4-MDBT) and 4,6-dimethyldibenzothiophene(4,6-DMDBT) in simulated diesel at room temperature were investigated. The results show, BET surface area of Cu-BTC is up to 1501m2/g. When the initial concentration of sulfur in 4-MDBT is 46.80mg S/L, the static equilibrium adsorption capacity of Cu-BTC for 4-MDBT in simulated diesel is 2.40mg S/gads, which is about 20 times than that of other adsorbents. When the initial concentration of sulfur in 4,6-DMDBT is 48.47mg S/L, the equilibrium adsorption capacity of Cu-BTC for 4,6-DMDBT in simulated diesel is 2.04mg S/gads. The adsorption isotherms of Cu-BTC for 4-MDBT and 4,6-DMDBT indicate that when the equilibrium concentration of sulfur is 50mg S/L, the adsorption performance of Cu-BTC for 4-MDBT and 4,6-DMDBT following the order is 4-MDBT&gt;4,6-DMDBT.

Selective oxidation of refractory sulfur compounds for the production of low sulfur transportation fuel

The current technologies for achieving low sulfur in diesel fuel are based on hydrotreating, which requires high temperature, high pressure and excessive supply of hydrogen. Oxidative desulfurization (ODS) is considered one of the promising new methods for super deep desulfurization, which could be carried out under very mild conditions (atmospheric pressure, <100 °C) without consumption of hydrogen. In this paper, development status of ODS process by major licensors are described as well as general concepts of ODS reaction. In addition, the ODS process has been categorized into single phasic and biphasic system according to the oxidants involved. Recent trends in both systems are reviewed in detail and future work is also proposed.

PM2.5 mass and species trends in Santiago, Chile, 1998 to 2010: The impact of fuel-related interventions and fuel sales

Improving air quality in Santiago has been a high priority for the Chilean government. In this paper, we examine trends of fine particulate matter (PM2.5) mass and species concentrations during the period 1998 to 2010 and explore the impact of fuel-related interventions and fuel sales on concentration changes. Smoothing spline functions were utilized to characterize and account for nonlinear relationships between pollutant concentrations and different parameters. Meteorology-adjusted PM2.5 concentrations were lower by 21.8 µg/m3 in 2010 compared to 1998. In this model, wind speed was the most important determinant of PM2.5 levels. A decrease in 24-hr average wind speed below 1.0 m/s was associated with a significant increase in daily PM2.5 levels, indicating a high sensitivity of PM2.5 concentrations to the accumulation of local emissions. The same regression model framework was applied to examine the trends of lead, bromine, and sulfur concentrations. Removal of lead and bromine from gasoline achieved dramatic decreases in their atmospheric concentrations. Nonetheless, both elements continue to persist, likely in the form of PbBrCl. The reduction of diesel sulfur content from 1,500 to 50 ppm corresponded to a 32% decrease in particulate sulfur levels. Lastly, a surge in PM2.5 was observed in 2005–2008. Further regression analyses suggested this was prompted by a rise in monthly petroleum-based fuel sales. Implications: In this paper, we elucidate meteorology-adjusted trends of PM2.5 mass and species concentrations in Santiago and assess the efficacy of fuel-related interventions, such as the removal of lead from gasoline and reduction of sulfur content in diesel. In addition, we explore the impact of fuel sales on PM2.5 trends. Given that fuel consumption is likely to increase further in this rapidly growing city, understanding its impact on PM2.5 trends can inform future air quality control efforts in Santiago. Supplemental Materials: Supplemental materials are available for this paper. Go to the publisher's online edition of the Journal of the Air & Waste Management Association.

Tailor‐Made Mesoporous Ti‐SBA‐15 Catalysts for Oxidative Desulfurization of Refractory Aromatic Sulfur Compounds in Transport Fuel

AbstractWe propose large‐pore titanium‐containing organosilylated mesoporous silica (Ti‐SBA‐15) as a highly efficient catalyst for the oxidative desulfurization (ODS) of refractory aromatic sulfur compounds with the aim to produce ultra‐low sulfur diesel. To achieve this, we synthesized a series of mesoporous Ti‐SBA‐15 catalysts according to a new procedure. The procedure is based on the controlled grafting of titanium chelates on SBA‐15 silica at low temperatures (5 °C). This specific synthesis procedure ensured a high dispersion of the required 4‐coordinate tetrahedral Ti4+ sites located on the mesopore surface. To substantiate the influence of the titanium content and mesopore size on the ODS performance of the catalysts, the parameters were varied in the range of 0.7 to 4.7 mol % (Si/Ti) and 5.1 to 9.0 nm, respectively. The resulting Ti‐SBA‐15 catalysts were then tested in the oxidative desulfurization (ODS) of model sulfur‐containing compounds in the presence of cumene hydroperoxide (CHP) as the organic oxidant. The ODS of a real industrial diesel fuel was also carried out in a continuous fixed bed reactor with the same Ti‐SBA‐15 catalysts and CHP. The catalytic results revealed that the Ti‐SBA‐15 catalysts with the largest pore sizes (&gt;7.3 nm) and highest Ti contents (&gt;2.8 mol %) were highly active catalysts for ODS reactions. Moreover, the catalysts with large pores and high Ti loadings appeared to be stable for over 30 h and were far less prone to deactivation than their equivalent Ti‐SBA‐15 samples with smaller pore diameters and lower Ti contents.

Effects of Aromatics, Diesel Additives, Nitrogen Compounds, and Moisture on Adsorptive Desulfurization of Diesel Fuel over Activated Carbon

The present research is concerned with the question of why activated carbons that show good adsorption uptake for model diesel sulfur compounds are not effective for real diesel fuels. In this work, the effects of aromatics, O-containing fuel additives, nitrogen compounds, and moisture present in real diesel fuel on adsorption desulfurization (ADS) over a commercial activated carbon (AC-WPH) were investigated. Polyaromatics such as phenanthrene show a significant inhibiting effect on ADS, even at a concentration of less than 1.0 wt %, while monoaromatics such as butylbenzene, even up to 10 wt %, have a negligible effect. The adsorption of different sulfur compounds over AC-WPH can be attributed mainly to the interaction of their conjugated π electrons with the carbon surface, where the electron-donating methyl groups further enhance the interaction. Trace amounts of O-containing diesel additives, nitrogen compounds, and moisture all have inhibiting effects on adsorptive desulfurization over AC-WPH, which ...

Effect of the subsampling ratio in the application of subagging for multivariate calibration with the successive projections algorithm

This paper concerns the effect of the subsampling ratio on the subagging approach for multiple linear regression with variable selection by the successive projections algorithm. Investigations involving simulated data, as well as near-infrared spectrometric determination of moisture and protein in wheat and distillation temperatures (T10 and T90), specific mass and sulphur in diesel, are presented. In terms of prediction ability and sensitivity to noise, the best results were obtained for subsampling ratios around 40%.

Liquid−Liquid Equilibria for {1-Ethyl-3-methylimidazolium Diethylphosphate or 1-Ethyl-3-methylimidazolium Ethylsulfate} + 4,6-Dimethyldibenzothiophene + Dodecane Systems at 298.2 K and 313.2 K

Liquid−liquid equilibrium (LLE) data for {1-ethyl-3-methylimidazolium diethylphosphate ([emim][DEtPO4]) or 1-ethyl-3-methylimidazolium ethylsulfate ([emim][EtSO4])} + 4,6-dimethyl-dibenzothiophene (4,6-DMDBT) + dodecane systems, at (298.2 and 313.2) K and atmospheric pressure (≈ 95 kPa), were determined by refractometry. 4,6-DMDBT is one of the most difficult diesel sulfur pollutants to remove by the conventional process of hydrodesulfurization (HDS). Extraction of 4,6-DMDBT from dodecane (used as model diesel oil) was analyzed in terms of solute distribution coefficient, solvent selectivity, and percent of extraction. The results indicate that [emim][DEtPO4] is a better solvent for extractive desulfurization of dodecane than [emim][EtSO4]. The Hand and Othmer−Tobias correlations, used to ascertain the quality of the experimental data, presented R2 > 0.98 for systems with [emim][DEtPO4] and R2 > 0.96 for systems with [emim][EtSO4]. The nonrandom two-liquid (NRTL) model was used to correlate the LLE data a...

Recent Trends in the Cleaning of Diesel Fuels via Desulfurization Processes

This article is a selective review of new approaches and emerging technologies for ultra-clean (ultra-low sulfur) diesel fuels. The issues of diesel deep desulfurization are becoming more serious because the crude oils are getting higher in sulfur content, while the regulated sulfur limits are becoming lower and lower. Deep reduction of diesel sulfur (from 500 to <15 ppmw sulfur) is dictated largely by 4,6-dimethyldibenzothiophene, which represents the least reactive sulfur compounds that have substitutions on both 4- and 6-positions. The deep hydrodesulfurization (HDS) problem of diesel streams is exacerbated by the inhibiting effects of co-existing poly aromatics and nitrogen compounds in the feed as well as H2S in the product. New and more effective approaches and continuing catalysis and processing research are needed for producing affordable ultra-clean diesel fuels, because meeting the new government sulfur regulations in 2006–2010 is only a milestone. Desulfurization research should also take into consideration the fuel-cell fuel processing needs, which will have stringent requirements on desulfurization.