Total Aromatic Content Research Articles

Fluid catalytic cracking feed hydrotreatment and its severity impact on product yields and quality

This paper investigates the effect of fluid catalytic cracking (FCC) feed hydrotreatment and its severity increase on product yields and quality obtained in a commercial and a laboratory MAT FCC units. The hydrotreatment of Ural heavy vacuum gas oil reduces not only sulfur, nitrogen, Conradson carbon and metals content in the FCC feed but also increases the mononuclear aromatic hydrocarbons content by 8% absolute at almost no change in the total aromatics content. Regardless of this 8% increase of the mononuclear aromatics in the hydrotreated FCC feed the conversion increase in both commercial and laboratory MAT units was only 2%. The severity increase in the FCC feed hydrotreater leads to a higher conversion in the FCC, higher hydrogen transfer rate that results in higher isobutane/butylenes ratio, lower gasoline olefins content, and higher gasoline motor octane number. The hydrotreatment of the Ural heavy vacuum gas oil exhibited the same changes in FCC catalyst selectivities: lower coke and LCO selectivities and higher gasoline selectivity in both commercial riser FCC unit that has between 2 and 3 s time on stream, and the fixed bed reactor MAT unit, that has 30 s time on stream.

<b>Aliphatic and polycyclic aromatic hydrocarbons profiles of photomodified natural bitumen of Agbabu, Southwestern Nigeria</b>

The impact of sunlight on aliphatic and polycyclic aromatic hydrocarbons profiles of Agbabu natural bitumen in Nigeria was investigated. The raw flow type of the bitumen was purified and exposed to sunlight for six consecutive months. Different portions of the bitumen were withdrawn at an interval of one month and were separated into aliphatic and polycyclic aromatic hydrocarbon fractions by column chromatography, followed by the GC analyses of various fractions. The total aliphatic hydrocarbon content was found to be 485, 424, 416 and 392 g/kg for control, one, three and six months solar-irradiated bitumen samples, respectively; while the total polycyclic aromatic hydrocarbons content found in the control, one, three and six months solar-irradiated bitumen samples were 708, 733, 609 and 638 µg/g, respectively. The effects of sunlight on the compositional patterns of bitumen were discussed. KEY WORDS: Agbabu, Bitumen, Sunlight, GC, Aliphatic hydrocarbon, Polycyclic aromatic hydrocarbon Bull. Chem. Soc. Ethiop. 2010 , 24(3), 461-466.

INFLUENCES OF GRAFTING ON AROMATIC COMPOUNDS IN MUSKMELON BY SOLID PHASE MICROEXTRACTION WITH GC-MS

There has been an increase in popularity of grafting technique on muskmelon in agricultural production because grafting of melon increased its disease resistance to fusarium wilt, but melon's (Cucumis melo L.) quality has been more serious inferior than its own-rooted melon. The volatiles substance plays an important role in melon fruit quality. We have found very little reports in literature for melon grafting varieties and using solid-phase microextraction (SPME). The objective of this experiment was to identify volatile and semivolatile compounds in two melon cultivars 'Lu135' and 'Lu7475', using solid-phase microextraction (SPME) with gas chromatography-mass spectrometry (GC-MS). Fully ripe melon was squeezed through miracloth to produce rapid juice extracts for immediate headspace SPME GC-MS. One hundred forty two volatile compounds were separated in ripe muskmelon, they consisted of 56 esters, 27 alcohols, 3 aldehydes, 17 ketones, 21 alkenes and 18 other substances. Among these compounds, types of esters and alcohols were the important aroma components accounting for over 74.75-93.46% of total peak area. The most abundant compounds in two cultivars were acetic acid, phenylmethyl ester (21.65-36.43%), acetic acid, hexyl ester (6.05-12.95%), ethyl acetate (2.89-9.94%), 1-butanol, 2-methyl-, acetate (5.84-7.82%). The total aromatic compounds and characteristic aromatic esters contents decreased in grafted melons than the own-rooted melon. The delightful fruit aroma in grafting melon was lower and thinner in comparison to own-rooted. Meanwhile, the aroma components of melon were altered because of grafting in adopting of melon. However, the effect of grafting on aroma components was different between two varieties. The total esters content and category in 'Lu135' was obviously lower in grafting melons than own-rooted and it had little chance on 'Lu7475'.

Lung antioxidant and cytokine responses to coarse and fine particulate matter from the great California wildfires of 2008

The authors have previously demonstrated that wildfire-derived coarse or fine particulate matter (PM) intratracheally instilled into lungs of mice induce a strong inflammatory response. In the current study, the authors demonstrate that wildfire PM simultaneously cause major increases in oxidative stress in the mouse lungs as measured by decreased antioxidant content of the lung lavage supernatant fluid 6 and 24 h after PM administration. Concentrations of neutrophil chemokines/cytokines and of tumor necrosis factor (TNF)-α were elevated in the lung lavage fluid obtained 6 and 24 h after PM instillation, consistent with the strong neutrophilic inflammatory response observed in the lungs 24 h after PM administration, suggesting a relationship between the proinflammatory activity of the PM and the measured level of antioxidant capacity in the lung lavage fluid. Chemical analysis shows relatively low levels of polycyclic aromatic hydrocarbons compared to published results from typical urban PM. Coarse PM fraction is more active (proinflammatory activity and oxidative stress) on an equal-dose basis than the fine PM despite its lower content of polycyclic aromatic hydrocarbons. There does not seem to be any correlation between the content of any specific polycyclic aromatic hydrocarbon (or of total polycyclic aromatic hydrocarbon content) in the PM fraction and its toxicity. However, the concentrations of the oxidation products of phenanthrene and anthracene, phenanthraquinone and anthraquinone, were several-fold higher in the coarse PM than the fine fraction, suggesting a significant role for atmospheric photochemistry in the formation of secondary pollutants in the wildfire PM and the possibility that such secondary pollutants could be significant sources of toxicity in the wildfire PM.

Emissions in the exhaust of fishing boats after adding viscous agents into fuel oils

In order to avoid the illegal use of fishing boat fuel A (FBFA) by traveling diesel vehicles (TDVs) in Taiwan, alternatives that are easily distinguished from premium diesel fuel (PDF) were prepared to evaluate their suitability. Two new ingredients, pyrolysis fuel oil (PFO) and residue of desulfurization unit (RDS), were added into FBFA and formed PFO0.5 and RDS0.5, respectively. Along with FBFA, these three fuels were analyzed for their chemical and physical properties. Furthermore, they were used by three fishing boats with different sizes, output powers, and weights. The engine performances and pollutant emissions were examined and monitored. Experimental results show that there are significant differences in appearance between PDF and the two new blended fuels (PFO0.5 and RDS0.5), and thus misuse or illegal use of FBFA could be substantially reduced. The fuel consumption, which is negatively related to the heating value of fuels, is in order of FBFA < PFO0.5 = RDS0.5. In contrast with using FBFA in the three fishing boats, using RDS0.5 resulted in a decrease in CO and NO x emissions, while the PM emission factors (g bhp − 1 h − 1 and g L − 1 -fuel) were reduced by approximately 36% and 33%, respectively. Owing to the higher total aromatic content in PFO0.5 and RDS0.5, total-PAH concentrations in the exhausts from the three fishing boats using PFO0.5 and RDS0.5 were slightly (1.2 and 1.1 times, respectively) higher than for those using FBFA. Nevertheless, the estimated total BaP eq from the three fishing boats using RDS0.5 was 27.5, 19.5, and 8.25% lower than those using FBFA. With using PFO0.5, they were totally different, at 23.5, 2.79, and 2.58% higher. With regard to looking different to PDF, RDS0.5 is superior to PFO0.5, and is thus recommended as a better alternative to FBFA, particularly because it can help lower more emissions of CO, NO x , PM and BaP eq.

Characterization of Catalytic Reforming Streams by NIR Spectroscopy

The ability of near-infrared (NIR) spectroscopy with multivariate methods of analysis to predict the chemical composition of different process streams obtained from a catalytic reforming unit was demonstrated. One hundred and forty samples were used to develop calibration models by partial least-squares (PLS) regression. For calibration and validation stages, 92 and 48 samples were employed, respectively. Total paraffin, total isoparaffin, total naphthene, and total aromatic content in naphtha have been successfully determined. Prediction of individual carbon chain length (C6−C8) in each hydrocarbon family was also studied with promising results. Calibration models for compounds with carbon chain length smaller than C6 and bigger than C8 were not developed because the concentration ranges of those components were too low, and there is a limitation in NIR sensitivity. The proposed methodology takes less than 5 min to perform, and it can be used for online process control. Besides, it is faster than the sta...

Effect of Different Humic Substances on the Fate of Diuron and Its Main Metabolite 3,4-Dichloroaniline in Soil

Humic substances (HS) are the dominant constituents of soil organic matter (SOM). The interactions between the phenylurea herbicide 3-(3,4-dichlorophenyl)-1,1-dimethylurea (diuron) and several HS fractions, purified from various soil horizons, were studied. One commercial humic acid (HA) was included for comparison. Diuron was shown to adsorb significantly, but reversibly, to purified HA while sorption to fulvic acid (FA) was less pronounced. The sorption abilities of the purified HS fractions were correlated with their total aromatic content. In natural soils, SOM was the main adsorbent of diuron, but the organic matter partition coefficient was larger in sandy compared to clayey soils. Degradation of diuron in natural soils was slow and incomplete. Inoculation of a sandy C-horizon with a diuron-degrading bacterial strain led to substantial diuron degradation, but the addition of purified FA and HA to these inoculated soils decreased this degradation. The main metabolite produced during diuron degradation, 3,4-dichloroaniline, was bound irreversibly to HS within days after formation.

Polycyclic Aromatic Hydrocarbons in Spanish Olive Oils: Relationship between Benzo(a)pyrene and Total Polycyclic Aromatic Hydrocarbon Content

Samples of Spanish virgin olive oils (VOOs) from different categories, origins, varieties, and commercial brands were analyzed by HPLC with a programmable fluorescence detector to determine the content of nine heavy polycyclic aromatic hydrocarbons (PAHs): benzo(a)anthracene, chrysene, benzo(e)pyrene, benzo(b)fluoranthene, benzo(k)fluoranthene, benzo(a)pyrene, dibenzo(a,h)anthracene, benzo(g,h,i)perilene, and indeno(1,2,3-c,d)pyrene. Samples of olive pomace and crude olive pomace oils were also investigated. Benzo(a)pyrene concentrations were below the allowed limit in the European Union (2 microg/kg) in 97% of the VOO samples. Only those samples coming from contaminated olive fruits or obtained in oil mills with highly polluted environments exceeded this value. High correlation coefficients (<0.99) were obtained between the contents of benzo(a)pyrene and the sum of the nine PAHs for all of the analyzed categories, suggesting that benzo(a)pyrene could be used as a marker of the content of these nine PAHs in olive oils.

Investigation of the Heterogeneous Catalytic Transformation of Vegetable Oil/Gas Oil Blends

The applicability of vegetable oils (tryglycerides) and their derivates is well-known for a long time. The main goal (to produce fuels from non-fossil based energy source) has been extended with the global aims of reducing the environmental pollution. Therefore the main objective now is to produce, store, transport and use fuels with lower emission levels. Until the last couple of years the vegetable oils were mostly transesterified catalytically to biodiesel to produce fuels. Because of the numerous disadvantages of biodiesel production and application the alternative chemical transformations of triglycerides were started to be studied intensively. One of the best alternative is to convert the vegetable oils (or other materials containing triglycerides) and/or their blends with gas oil to hydrocarbons rich in paraffins. These compounds can be applied in Diesel-engines directly or blended with petroleum-based gas oil. In our experimental work we examined the heterogeneous catalytic conversion of light gas oil fraction containing 10% sunflower oil on transition metal/Al2O3 catalyst. Our objective was to study the effect of the operating parameters to the yield of liquid organic products, to the yield of the fraction of gas oil boiling point range and to the product properties. Based on our results it can be concluded that with the catalytic hydrogenation of the feedstock containing 10% sunflower oil products with excellent properties can be produced with high yield. The product gas oil had ³10 mg/kg sulphur and nitrogen content, lower than 10% total aromatic content and ³-5 °C cold filter plugging point. The cetane number of the products was significantly higher than the limit (51) of the EN 590:2004 standard.

Near Infrared Spectroscopic Determination of Diesel Fuel Parameters Using Genetic Multivariate Calibration

The use of full spectral region from near infrared spectroscopic analysis does not always end up with a good multivariate calibration model as many of the wavelengths do not contain necessary information. Due to the complexity of the spectra, some of the wavelengths or regions may, in fact, disturb the model-building step. Genetic algorithms are one of the useful tools for solving wavelength selection problems and may improve the predictive ability of conventional multivariate calibration methods. This study demonstrates application of genetic algorithm-based multivariate calibration to near infrared spectroscopic determination of several diesel fuel parameters. The parameters studied are cetane number, boiling and freezing point, total aromatic content, viscosity, and density. Multivariate calibration models were generated using genetic inverse least squares (GILS) method and used to predict the diesel fuel parameters based on their near infrared spectra. For each property, a different data set was used and in all cases the number of samples was around 250. Overall, percent standard error of prediction (%SEP) values ranged between 2.48 and 4.84% for boiling point, total aromatics, viscosity, and density. However, %SEP results for cetane number and freezing point were 11.00% and 14.86%, respectively.

Investigation of hydrodearomatization of prehydrogenated gas oil fractions on Pt–Pd/H-USY catalysts

Hydrodearomatization (HDA), hydrodenitrogenation (HDN) and hydrodesulphurization (HDS) of real gas oils (various sulphur, nitrogen and total aromatic content) was investigated over Pd, Pt catalysts supported on USY zeolite, whose Pd/Pt mass ratio was varied between 6:1 and 1:3, and total metal contents were between 0.90 and 0.93. The effect of Pd/Pt ratio on HDA, HDN and HDS activities is presented. The advantageous process parameters for HDA, HDN and HDS of gas oils over a selected catalyst (e.g. Pd/Pt mass ratio 3:1) were determined. Additionally, the effect of key process parameters (temperature, pressure, LHSV) on the yield and quality of products was studied. Under optimal process parameters the HDA efficiency decreased with sulphur and nitrogen content of feed. The rate of HDA enhanced with Pt content of the catalyst while HDS and HDN efficiency increased with Pd content. The maximum aromatic saturation was 85% and it decreased with sulphur and nitrogen content of the feed.

Characteristics of DOC Exported from Northern Hardwood Forests Receiving Chronic Experimental NO 3 − Deposition

Sugar maple (Acer saccharum Marsh.)-dominated northern hardwood forests of the Great Lakes Region commonly receive elevated levels of atmospheric nitrate (NO 3 − ) deposition, which can alter belowground carbon (C) cycling. Past research has demonstrated that chronic experimental NO 3 − deposition (3 g N m−2 y−1 above ambient) elicits a threefold increase in the leaching loss of dissolved organic carbon (DOC). Here, we used DOC collected from tension-cup lysimeters to test whether increased DOC export under experimental NO 3 − deposition originated from forest floor or mineral soil organic matter (SOM). We used DOC radiocarbon dating to quantify C sources and colorimetric assays to measure DOC aromaticity and soluble polyphenolic content. Our results demonstrated that DOC exports are primarily derived from new C (<50-years-old) in the forest floor under both ambient and experimental NO 3 − deposition. Experimental NO 3 − deposition increased soluble polyphenolic content from 25.03 ± 4.26 to 49.19 ± 4.23 μg phenolic C mg DOC−1, and increased total aromatic content as measured by specific UV absorbance. However, increased aromatic compounds represented a small fraction (<10%) of the total observed increased DOC leaching. In combination, these findings suggest that experimental NO 3 − deposition has altered the production or retention as well as phenolic content of DOC formed in forest floor, however exact mechanisms are uncertain. Further elucidation of the mechanism(s) controlling enhanced DOC leaching is important for understanding long-term responses of Great Lakes forests to anthropogenic N deposition and the consequences of those responses for aquatic ecosystems.

Caracterización rápida del gasóleo mediante espectroscopía infrarroja

It is described an analytical method to characterize a diesel sample in a three minutes period using a portable infrared analyzer. The new models incorporated in the equipment were developed using the software of the equipment and analytical data generated in Instituto Colombiano del Petróleo (ICP), Ecopetrol S.A. labs. Based on this technique it is possible to obtain information about total aromatic content, sulphur content, polynuclear aromatic content and distillation temperatures in a diesel fuel sample. According to the validation results that showed some error bigger than the reproducibility of the original methods, it is recommended to use the proposed method as a semi quantitative one.

Characterization of Polycyclic Aromatic Hydrocarbons from the

Diesel fuels governed by U.S. regulations are based on the index of the total aromatic contents. Three diesel fuels, containing various fractions of light cycle oil (LCO) and various sulfur, total polyaromatic, and total aromatic contents, were used in a heavy-duty diesel engine (HDDE) under transient cycle test to assess the feasibility of using current indices in managing the emissions of polycyclic aromatic hydrocarbons (PAHs) from HDDE. The mean sulfur content in LCO is 20.8 times as much as that of premium diesel fuel (PDF). The mean total polyaromatic content in LCO is 28.7 times as much as that of PDF, and the mean total aromatic content in LCO is 2.53 times as much as that of PDF. The total polyaromatic hydrocarbon emission factors in the exhaust from the diesel engine, as determined using PDF L3.5 (3.5% LCO and 96.5% PDF), L7.5 (7.5% LCO and 92.5% PDF), and L15 (15% LCO and 85% PDF) were 14.3, 25.8, 44, and 101 mg L−1, respectively. The total benzo(a)pyrene equivalent (BaPeq) emission factors in the exhaust from PDF, L3.5, L7.5, and L15 were 0.0402, 0.121, 0.219, and 0.548 mg L−1, respectively. Results indicated that using L3.5 instead of PDF will result in an 80.4% and a 201% increase of emission for total PAHs and total BaPeq, respectively. The relationships between the total polyaromatic hydrocarbon emission factor and the two emission control indices, including fuel polyaromatic content and fuel aromatic content, suggest that both indices could be used feasibly to regulate total PAH emissions. These results strongly suggest that LCO used in the traveling diesel vehicles significantly influences PAH emissions.

Nutritional composition of chickpea ( Cicer arietinum L.) as affected by microwave cooking and other traditional cooking methods

The effects of microwave cooking and other traditional cooking methods such as boiling and autoclaving on the nutritional composition and anti-nutritional factors of chickpeas ( Cicer arietinum L.) were studied. Cooking treatments caused significant ( P < 0.05 ) decreases in fat, total ash, carbohydrate fractions (reducing sugars, sucrose, raffinose and stachyose, while verbascose was completely eliminated after cooking treatments), antinutritional factors (trypsin inhibitor, haemagglutinin activity, tannins, saponins and phytic acid), minerals and B-vitamins. Cooking treatments decreased the concentrations of lysine, tryptophan, total aromatic and sulfur-containing amino acids. However, cooked chickpeas were still higher in lysine, isoleucine and total aromatic amino acid contents than the FAO/WHO reference. The losses in B-vitamins and minerals in chickpeas cooked by microwaving were smaller than those cooked by boiling and autoclaving. In-vitro protein digestibility, protein efficiency ratio and essential amino acid index were improved by all cooking treatments. The chemical score and limiting amino acid of chickpeas subjected to the various cooking treatments varied considerably, depending on the type of treatment. Based on these results, microwave cooking is recommended for chickpea preparation, not only for improving nutritional quality (by reducing the level of antinutritional and flatulence factors as well as increasing in-vitro protein digestibility and retention rates of both B-vitamins and minerals), but also for reducing cooking time.

Impact of using fishing boat fuel with high poly aromatic content on the emission of polycyclic aromatic hydrocarbons from the diesel engine

Because of the fishery subsidy policy, the fishing boat fuel oil (FBFO) exemption from commodity taxes, business taxes and air pollution control fees, resulted in the price of FBFO was ∼50% lower than premium diesel fuel (PDF) in Taiwan. It is estimated that ∼650,000 kL FBFO was illegally used by traveling diesel-vehicles (TDVs) with a heavy-duty diesel engine (HDDE), which accounted for ∼16.3% of the total diesel fuel consumed by TDVs. In this study, sulfur, poly aromatic and total-aromatic contents in both FBFO and PDF were measured and compared. Exhaust emissions of polycyclic aromatic hydrocarbons (PAHs) and their carcinogenic potencies (BaP eq) from a HDDE under transient cycle testing for both FBFO and PDF were compared and discussed. Finally, the impact caused by the illegal use of FBFO on the air quality was examined. Results show that the mean sulfur-, poly aromatic and aromatic-contents in FBFO were 43.0, 3.89 and 1.04 times higher than that of PDF, respectively. Emission factors of total-PAHs and total-BaP eq obtained by utilizing FBFO were 51.5 and 0.235 mg L −1-Fuel, which were 3.41 and 5.82 times in magnitude higher than obtained by PDF, respectively. The estimated annual emissions of total-PAHs and total-BaP eq to the ambient environment due to the illegally used FBFO were 23.6 and 0.126 metric tons, respectively, which resulted in a 17.9% and a 25.0% increment of annual emissions from all mobile sources, respectively. These results indicated that the FBFO used illegally by TDVs had a significant impact on PAH emissions to the ambient environment.

Estimation of Total Aromatic Content of Vacuum Gas Oil (VGO) Fractions (370−560 °C) by 1H NMR Spectroscopy

In this paper, a quick and direct method has been developed for the quantitative estimation of total aromatics and saturates in a vacuum gas oil (VGO) fractions boiling range (370−560 °C), using 1H NMR spectroscopic techniques. The method is based on the estimation of the average alkyl chain length of substituents on aromatics and the relative group molecular weight of aromatics and saturates. The total aromatics are estimated from the derived equation, which takes into account the relative distribution of CHn (n = 0, 1, 2, 3) groups of aromatics substituents and saturates. The exact assignment of aromatics substituents of α-CHn (n = 1, 2, 3) has been performed by the application of 1H/13C multipulse NMR techniques, such as DEPT-135 and 2D HSQC (edited) (heteronuclear single quantum coherence). The results obtained for several VGO samples from different sources have been in close agreement with those from the open chromatography method (ASTM D-2549-91) and the thin-layer chromatography−flame ionization de...

Determination of aromatic hydrocarbons in gasolines by flow modulated comprehensive two-dimensional gas chromatography

Valve based/flow modulated comprehensive two-dimensional gas chromatography–flame ionization detection (GC × GC–FID) was used for quantification of C 6 through C 12 aromatic hydrocarbons by carbon number in gasolines. A 0.53 mm i.d. non-polar first dimension column was coupled to a 0.53 mm i.d. polar second dimension column through a double loop eight port valve modulator. Depending on the sample type, normalized percent and internal standard (I.S.) quantification was performed. For normalized percent quantification, a one-point calibration performed with one aromatic compound per carbon number/class provided an average % accuracy of 2.1% and a short-term n − 1 relative standard deviation of 1.0%. For total aromatic compounds good agreement with the more complex conventional multidimensional GC technique was obtained. However, GC × GC has certain advantages over most other methods, mainly increased selectivity for total and carbon number aromatic content. The identification of the aromatic hydrocarbons was confirmed by GC × GC–MS.

Evaluation of aromatic hydrocarbons by spectrofluorometry in marine sediments and biological matrix: what reference should be considered?

Evaluation of total aromatic hydrocarbons in marine samples is usually determined spectrofluorometrically relative to a known reference. This reference may be either a crude oil, or a mixture of certain aromatic hydrocarbons. This work discusses this aspect, showing how the evaluation of total aromatic hydrocarbons contents in marine sediments and organisms depends upon the reference. For evaluating the total aromatic hydrocarbon content in samples, the fluorescence signal of two standards was used systematically as reference. The results obtained varied in the ratio 1 and 1/8 using Ropme oil (crude oil of Kuwait) and chrysene, respectively. To cite this article: N. Mzoughi et al., C. R. Chimie 8 (2005) .

Automotive Gasolines. Long-Term Requirements for Composition and Properties

The requirements for the composition and quality of automotive gasolines by 2010 for reducing the toxicity of exhaust gases are examined. Data on the component composition and environmental indexes of all brands of gasoline manufactured in 2002–2003 and tested with a set of qualification evaluation methods are generalized. The possibility of meeting the demand of Russian motor vehicles for Euro–2 and Euro–3 gasolines in 2005 is demonstrated. Expansion of manufacture of these gasolines is limited by the total aromatic hydrocarbon content, including benzene. The use of iron– and manganese–containing antiknock compounds at a maximum metal concentration of 18 mg/dm3 could be a temporary measure.