Total Aromatic Content Research Articles

Hydrocarbon-Type Analysis of Middle Distillates by Mass Spectrometry and NMR Spectroscopy TechniquesA Comparison

In the present work, mass spectroscopy (MS) and 1H nuclear magnetic resonance (NMR) spectroscopy methods have been used to determine the total aromatics content in diesel-range products. The data indicate that both the methods exhibit good correlation among each other, although the MS method has a tendency to provide higher aromatic results for the case of samples that contain a greater amount of sulfur. The possible factors responsible for variations in the results from both techniques have been discussed. The reproducibility of the aromatic data is dependent on the intrinsic nature of the technique and the analytical method applied. This systematic comparative study has proved that NMR spectroscopy is a fast and reliable alternative method to MS for estimation of the total aromatics content in diesel-range products.

Genotoxicity of PM 10 and extracted organics collected in an industrial, urban and rural area in Flanders, Belgium

The variation in the genotoxic potency of PM 10 in vitro in relation to the particle source type was investigated. Particles were collected at one urban, one rural, and one industrial site in Flanders. Genotoxicity was assessed using four different in vitro test systems exposed to PM 10 in suspension and to the organic extracts of PM 10. Two of these systems were bacterial assays: the Salmonella mutagenicity test and the Vitotox test. In addition, the Comet assay and Micronucleus test were performed using human blood cells. Results show that exposure to PM 10 and the organic extracts from both urban and industrial areas causes significant genetic damage. The Salmonella mutagenicity test was most suitable for the screening of PM 10 and the organic extracts; the Micronucleus test was most suitable only for the screening of organic extracts, and original particles were toxic for the exposed lymphocytes. Clear dose–response curves were not established in the Comet and Vitotox assay, and organic extracts were apparently toxic in the latter. The total polycyclic aromatic hydrocarbon content of the organic extracts, as measured with GC/MS, ranged between 1 and 6 ng/m 3. Results obtained in this study suggest that PM 10 causes DNA damage and mutations. The use of biological tests for the screening of air samples is useful to complement air quality control by chemical measurements.

04/00524 Integrated IAO model for prediction of VOC emissions from building material: Haghighat, F. and Huang, H. Building and Environment, 2003, 38, (8), 1007–1017.

The oxidation of the organic substrate present in wastewaters generated in wine distilleries (“wine vinasses”) is studied by both an ozonation process and by an aerobic activated sludge system. The ozonation process is conducted in a subsequent first discontinuous and a second continuous periods. Values are reported of the organic matter removal, measured as chemical oxygen demand (COD) (5–25.2%) and as total aromatic compounds content (16.8–51.4%). The influences of the inlet ozone partial pressure, the hydraulic retention time in the reactor and the presence of UV radiation and H2O2 in addition to ozone are established. Approximate kinetic studies are conducted for both periods which lead to the evaluation of the apparent rate constants for the substrate decomposition 216 l/(mol O3 h) and 232 l/(g COD h), respectively. In the aerobic degradation by the activated sludge system, the evolution of the organic substrate and biomass are followed during both the discontinuous and continuous stages of the whole process, and COD removals from 31 to 85% are obtained for a hydraulic retention time between 24 and 72 h. For the first stage, a kinetic study is performed by using the Contois model, which applied to the experimental data provides the specific kinetic parameters: qmax=0.190 g COD/(g volatile suspended solids (VSS) h) and K1=6.48 g COD/g VSS. For the continuous period, the kinetic study carried out provides the specific rate constant for the substrate decomposition, q=0.027 g COD/(g VSS h).

1H NMR Spectroscopic-Based Method for the Estimation of Total Aromatic Content of Aviation Turbine Fuels (ATF): Comparison with Liquid Chromatographic Methods

This work describes the development of a direct and quick method based on 1H NMR spectroscopy for the determination of total aromatic content of jet and aviation turbine fuels (ATF). The method is based on the calculation of the average group molecular weight of aromatics from the integral intensities of characteristic regions of aromatics 6.5−8.0 ppm and α-subsituents (2.1−3.0 ppm). The average chain length of the alkyl subsituents on aromatic rings (other than methyl groups) has been determined from the 1H NMR spectrum of pure aromatic fractions of a few aviation fuels. The NMR results have been compared, and have been found to be well correlated with the other standard methods based on liquid chromatography (LC) (ASTM-D1319 (FIA) and IP-436 (HPLC)). The results obtained from the three investigated methods NMR, FIA, and HPLChave been statistically evaluated and found to give equivalent results. The developed 1H NMR method is quite fast and reliable, and offers an alternative to long and tedious LC-based methods in routine quality control.

Kinetics of the ozonation and aerobic biodegradation of wine vinasses in discontinuous and continuous processes

The oxidation of the organic substrate present in wastewaters generated in wine distilleries (“wine vinasses”) is studied by both an ozonation process and by an aerobic activated sludge system. The ozonation process is conducted in a subsequent first discontinuous and a second continuous periods. Values are reported of the organic matter removal, measured as chemical oxygen demand (COD) (5–25.2%) and as total aromatic compounds content (16.8–51.4%). The influences of the inlet ozone partial pressure, the hydraulic retention time in the reactor and the presence of UV radiation and H2O2 in addition to ozone are established. Approximate kinetic studies are conducted for both periods which lead to the evaluation of the apparent rate constants for the substrate decomposition 216l/(molO3h) and 232l/(gCODh), respectively. In the aerobic degradation by the activated sludge system, the evolution of the organic substrate and biomass are followed during both the discontinuous and continuous stages of the whole process, and COD removals from 31 to 85% are obtained for a hydraulic retention time between 24 and 72h. For the first stage, a kinetic study is performed by using the Contois model, which applied to the experimental data provides the specific kinetic parameters: qmax=0.190gCOD/(gvolatile suspended solids (VSS)h) and K1=6.48gCOD/gVSS. For the continuous period, the kinetic study carried out provides the specific rate constant for the substrate decomposition, q=0.027gCOD/(gVSSh).

Fourier transform Raman spectroscopy of Syncrude Sweet Blend distillation fractions: the 200–1800 cm −1 region

The fingerprint (200–1800 cm −1) region in FT-Raman spectra of Syncrude Sweet Blend (SSB) and its three constituent distillation fractions (naphtha, light gas oil and heavy gas oil) was analyzed in detail in this study. Approximately 50 bands were observed and assigned to functional groups in saturated (alkanes) and unsaturated (aromatics) species. Characteristic bands for mono-, bi-, and tricyclic aromatics were identified and used to quantify these groups in SSB and the distillation fractions. Total aromatics content was determined using the carboncarbon stretching bands in the 1600-cm −1 region, and shown to agree with earlier results obtained from the CH stretching region. The bands due to mono- and bicyclic aromatics permitted calculation of the relative abundances of these species with an accuracy equivalent to that obtained using NMR spectroscopy, a traditional method for measuring this quantity.

Determination of benzene and total aromatics in commercial gasolines using packed column GC and NMR techniques

A simple, accurate and rapid method has been developed for the estimation of benzene and total aromatics (0.5–50% w/w) including heavier aromatics (C 8, C 9, and C 10) in commercial gasoline using packed column GC and NMR techniques. The benzene content can be estimated as low as 0.1% w/w. The response of a flame ionisation detector (FID) to each major aromatic group in gasoline was calculated using internal standard. The results have been compared with the NMR and standard ASTM D5580 methods. The limitations of NMR and GC techniques for the estimation of total aromatics particularly in reformulated gasoline containing oxygenates have been discussed and attempts have been made to overcome problems associated with the analysis. The results obtained by both the techniques for a number of commercial gasoline samples containing olefins or free of olefins received from different refineries processing variety of crudes using different refining technologies have shown excellent correlation. The 1H NMR method has a wider scope, convenient and fast, and also applicable to heavier naphtha. The method can routinely be adopted for the quality control of commercial gasoline at refinery as well as marketing terminals for monitoring benzene and total aromatic content. The time consumption for single run using gas chromatographic technique is approximately 35 min.

Nutritional composition and antinutritional factors of chickpeas (Cicer arietinum L.) undergoing different cooking methods and germination.

The effects of cooking treatments (boiling, autoclaving and microwave cooking) and germination on the nutritional composition and antinutritional factors of chickpeas were studied. Cooking treatments and/or germination caused significant (p < 0.05) decreases in fat, total ash, carbohydrate fractions, antinutritional factors, minerals and B-vitamins. Germination was less effective than cooking treatments in reducing trypsin inhibitor, hemagglutinin activity, tannins and saponins; it was more effective in reducing phytic acid, stachyose and raffinose. Cooking treatments and germination decreased the concentrations of lysine, tryptophan, total aromatic and sulfur-containing amino acids. However, cooked and germinated 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 in those cooked by boiling and autoclaving. Germination resulted in greater retention of all minerals and B-vitamins compared to cooking treatments. In vitro protein digestibility, protein efficiency ratio and essential amino acid index were improved by all treatments. The chemical score and limiting amino acid of chickpeas subjected to the various treatments varied considerably, depending on the type of treatment. Based on these results, microwave cooking appears to be the best alternative for legume preparation in households and restaurants.

Effect of fuel aromatic content on PAH emission from a heavy-duty diesel engine

Polycyclic aromatic hydrocarbons (PAHs) emission tests for a heavy-duty diesel engine fueled with blend base diesel fuel by adding batch fractions of poly-aromatic and mono-aromatic hydrocarbons, Fluorene and Toluene, respectively, were simulated to five steady-state modes by a DC-current dynamometer with fully automatic control system. The main objective of this study is to investigate the effect of total aromatic content and poly-aromatic content in diesel fuels on PAH emission from the HDD engine exhaust under these steady-state modes. The results of this study revealed that adding 3% and 5% (fuel vol%) Fluorene in the diesel fuel increases the amount of total-PAH emission by 2.6 and 5.7 times, respectively and increases the amount of Fluorene emission by 52.9 and 152 times, respectively, than no additives. However, there was no significant variation of PAH emission by adding 10% (vol%) of Toluene. To regulate the content of poly-aromatic content in diesel fuel, in contrast to the total aromatic content, will be more suitable for the management of PAH emission.

Treatment of black-olive wastewaters by ozonation and aerobic biological degradation

The degradation of the organic pollutants present in black-olive wastewater was carried out by ozonation, aerobic biological degradation, and the combination of two successive steps: an aerobic biological process followed by an ozonation. Contaminant removal was followed by means of global parameters directly related to the concentration of organic compounds in those effluents: chemical oxygen demand and total aromatic and phenolic contents. In the ozonation, an approximate kinetic study was performed to determine the apparent kinetic constants for the COD reduction, k COD, and for the total aromatic reduction, k A. In the aerobic biological degradation, the kinetic study was performed using the Monod model applied to the experimental data. In the combined process, a higher overall reduction in COD and aromatic content was achieved by the successive stages, and there was improved removal of the organic material during the second treatment. This enhancement was reflected in an increase in the apparent kinetic constants in the ozonation of the wastewater that had previously been treated aerobically, relative to the values obtained for the kinetic parameters in the single process experiment which were carried out under the same operating conditions.

Improvement of Process for Reducing the Benzene Content in Motor Gasoline Using an Emulsion Liquid Membrane and Distillation.

The process for removing toxic benzene from reformate based on an emulsion liquid membrane and distillation was improved and the calculation results of the new and old processes were compared. In the new process, benzene and non-aromatic hydrocarbons with boiling points close to that of benzene are removed from the reformate by two ordinary distillators to yield low-benzene reformate. The benzene and non-aromatic hydrocarbons are separated by the liquid membrane. The process calculation was carried out based on the previous empirical correlation of the mass transfer coefficient in the packed column permeator. Low-benzene reformate of the same flow rate and benzene content as in the previous process could be obtained by distillators with practical numbers of stages and operating conditions. The total aromatics content in the low-benzene reformate was higher than that of the original reformate, in contrast to the previous process. The octane number of the low-benzene reformate is thus higher than that of the original reformate. The yield of benzene was almost the same and the mass fraction of benzene in the product considerably increased. The flow rate of the stream to the permeator, consisting of the benzene and non-aromatics removed from the reformate, was naturally smaller than that in the previous process, where the original reformate was fed directly to the permeator. Therefore, the new process can treat larger amounts of the reformate than the previous process with the equivalent size of permeator. In the solvent recovery step, both the number of distillation stages and the heat energy required could be reduced. Solvent recovery absorbed the major part of the energy for the whole process. The energy requirement for the whole process was therefore lowered.

Treatment of olive mill wastewaters by ozonation, aerobic degradation and the combination of both treatments

The degradation of the pollutant organic matter present in olive oil mill wastewaters (OMW) is carried out by a single ozonation, a single aerobic degradation, and the combination of two successives steps: an ozonation followed by an aerobic degradation, and an aerobic degradation followed by an ozonation. In both single processes, the removal of this contaminant load is followed by means of global parameters which are directly related to the concentration of organic compounds in those effluents: chemical oxygen demand and total aromatic and phenolic contents. In the ozonation, an approximate kinetic study is performed which leads to the evaluation of the apparent kinetic constants for the aromatic reduction, kA. In the aerobic degradation, the kinetic study is conducted by using the Grau model, which is applied to the experimental data, and leads to the determination of the kinetic parameters of this model, K2 and n. In the combined processes, a higher COD global reduction is obtained by the successive stages, and an improvement in the removal of the organic material during the second treatment of both processes due to the pretreatment conducted is also observed. This enhancement is shown by an increase of the kinetic parameters (K2 and n in the aerobic degradation of the pre-ozonated wastewaters; the apparent constant kA in the ozonation of the wastewaters preliminary fermented aerobically), in relation to the values obtained for them in the single processes carried out at the same operating conditions. © 1999 Society of Chemical Industry

Ambient air aerosols, total polycyclic aromatic hydrocarbons (PAHs) for day and night time in the traffic areas of Central Taiwan

Day and night time ambient air samples from a traffic intersection were collected using Noll Rotary Impactor (NRI) and micro‐orifice uniform deposited impactor (MOUDI) samplers from June 1997 to August 1997 in central Taiwan to characterize the atmospheric particle mass, total Polycyclic aromatic hydrocarbons (PAHs) size distribution and total PAHs content for the day and night period in a traffic area. Twenty‐one individual PAHs were qualified and quantified by gas chromatography/mass spectrometry (GC/MS). The particle size distribution shifted to the coarse particle mode as the wind speed increased and shifted to the fine particle mode as the wind speed decreased in day and night time. Both coarse and fine particle concentrations in the day time were larger than that for night time. In addition, the ratios of the coarse to the fine particle concentrations ranged from 0.53 to 0.94 in the night time. This displayed the influence of traffic flow rate on the particle concentration differences in the day and night period. The correlation coefficients (R2) of particle concentration vs. wind speed were 0.64 and 0.34 for coarse and fine particles, respectively in the day time. It indicated that the higher the wind speed the higher the coarse particle concentration. The total PAHs size distribution for both day and night time were bimodal and the major bi‐peaks were located in the particle size range 0.31 ‐0.52 μm and 1.8–3.2 μm, respectively. In general, fine particles (<2.5 μm) have higher PAH content. This is due to the fact that soot from combustion sources consists primarily of fine particles and has a high PAH content. For particle size from 0.31 to 3.2 μm the mean total PAHs content were 5262 and 1738 μg/g for day and night time, respectively.

Influence of Diesel Fuel Cetane Number And Aromatic Content On Engine Exhaust Emissions

Abstract Exhaust emissions from a single cylinder heavy-duty diesel engine were measured to assess the effects of fuel properties on engine emissions. The AVL 8-mode steady-state simulation of the EPA transient test procedure was used in the engine tests. The results show that an increase in cetane number of the fuel reduced nitrogen oxide emissions (NOx), and possibly carbon monoxide emissions (CO). However, increasing the cetane number of the fuel caused an increase in particulate matter emissions (PM). The results also suggest that the fuel with lower total aromatic content produced slightly lower NOx and noticeably lower PM emissions. For fuels having comparable total aromatic contents, the one with a higher tri+-aromatic content produced slightly higher NOx emissions and noticeably higher PM emissions. However, the number of fuels in the fuel matrix and the fuel matrix design were not satisfactory to claim universality for the observed relationship between aromatics and engine exhaust emissions. Introduction It is generally agreed that exhaust emissions are affected by changes in fuel properties. However, the bulk of the emissions are dependent on the characteristics of the engine and its ability to utilize the fuel over the test cycle. Overall, the changes in emissions due to the independent changes in fuel properties appear small relative to the mean emission levels, although these changes are considered significant to achieve future emission standards. Most studies assume a priori causative relationships between primary fuel variables and certain emissions. These assumptions have not been clearly confirmed yet. The vast literature on the relationship between diesel fuel variables and exhaust emissions is full of contradicting results and claims. In this study, the main objective is to understand the influence of fuel properties on engine emissions. The fuel properties that are under consideration at this stage of the research program are the aromatic content and the cetane number. Ultimate questions that we aim to answer are:Is the oil sand derived diesel fuel different from the conventional crude oil derived diesel fuel as far as the exhaust emissions are concerned?Do polynuclear aromatics carry the same or more weight relative to mono- and di-aromatics in terms of their contribution to emissions? Experimental Test Engine The test engine used in this program was a single-cylinder Ricardo Proteus research engine. The engine was a direct injection type and had a displacement volume of 2 litres. Major engine configuration data are shown in Table 1. The performance and exhaust emission levels measured over the load and speed range were representative of current premium heavy-duty diesel engines. The speed and the load of the test engine were controlled independently by a dynamometer and a fuel control system. The fuel injection pump governing system was disabled to allow fixed fuelling levels. Static fuel injection timing can be adjusted 30 crank angle degrees either side of the top dead centre (TDC). To simulate a turbocharger, externally compressed air, controllable for temperature and pressure, was supplied to the engine.

Improving Accuracy in the Determination of Aromatics in Gasoline by Gas Chromatography--Mass Spectrometry

Petroleum industry studies show that the total aromatics content of a gasoline as determined by ASTM Standard Test Method D5769, Determination of Benzene, Toluene, and Total Aromatics in Finished Gasoline by Gas Chromatography/Mass Spectrometry, is consistently lower than results obtained using other standard test methods. Sources of this bias are investigated, and practical modifications to D5769 to reduce the bias are proposed.

Effects of Fuel Properties on Exhaust Emission from DI Diesel Engine.

Exhaust emissions (HC, CO, NO x , PM, and PAH (polycyclic aromatic hydrocarbons in PM)) from a commercial DI diesel engine were measured for petroleum-derived fuels with a wide range of fuel properties. Fuel properties such as cetane number, aromatic content and type, and distillation temperature were adjusted to be independent from each other. The test results showed that total aromatic content was the controlling factor for NO x emission, and PM emission mainly depended on polycyclic aromatic content in the fuel. The increases in PM emission with increase in aromatics was mainly caused by the increase in SOF emission. Both of NO x and PM emissions were seldom affected by cetane number and 90% distillation temperature. Therefore, chemical characteristics of fuel are the controlling factor for NO x and PM emission, not the physical properties. The amount of sulfate in PM proportionally increased with increase in sulfur content of fuel. PAH emission was evaluated by analyzing SOF using a high performance liquid chromatography with a chemiluminesence detector. Also, the PAH highly depended on aromatic content, and the emission characteristics caused by aromatics was quite similar to PM emission.

Hepatic enzyme induction and mutagenicity of airborne particulate matter from Santiago, Chile in the nourished and malnourished rat

1. Respirable, airborne particles in the ambient air in downtown Santiago, Chile, have been characterized for the seasonal variation in total polycyclic aromatic hydrocarbon content, 13 of which have been identified including the mutagens (benzo (a) pyrene, dibenzo (a, h) anthracene, benzo (a) anthracene, benzo (b) fluoranthene and indeno(1,2,3, c, d) pyrene amongst others. 2. Organic extracts derived from these particles were administered to both the nourished and malnourished rat and resulted in modulation of the hepatic mixed function oxidase system including induction of NADPH-cytochrome P450 reductase, cytochrome P4501A as determined by Western blot analysis and the associated ethoxyresorufin O deethylase and aryl hydrocarbon hydroxylase activities. 3. The cytochrome P4504A1-dependent 12-hydroxylation of lauric acid was induced in the malnourished state, but this activity was significantly inhibited by treatment of the animals with particle extracts in both nutritional states. 4. The particle extracts contained both direct and indirect-acting mutagens in the Ames test, and depending on the relative complement of both, resulted in either increased or decreased mutagenicity in the presence of S9 activation systems derived from both nourished and malnourished animals. 5. These results are discussed in the context of the interindividual risk assessment of airborne, particulate matter to man.

Aromatic hydrocarbons on surface waters of Admiralty Bay, King George Island, Antarctica

Total aromatic hydrocarbons were measured for surface seawater at 24 points in Admiralty Bay, Antarctica, during the summers of 1989, 1990, 1992 and 1993, using the spectrofluorimetric method. The levels varied between 0.05 and 8.86 μg l −1, but the majority of the samples presented levels below 1.00 μg l −1, so there were no alarming oil inputs in the area. In 1992, one point in front of the Antarctica Station Comandante Ferraz was sampled with an automatic pre-concentration unit capable of processing large volumes of seawater for GC-MS analysis. This water sample presented a total aromatic content of 0.080 μg l −1. Main two-ring aromatic compounds quantified by GC-MS were naphthalene, acenaphthylene, 1-methylnaphthalene, 2-methylnaphthalene and acenaphthene. Of the three-ring polycyclic aromatic hydrocarbons (PAHs), phenanthrene contributes more than anthracene. Of the four-ring members, fluoranthene is more abundant than pyrene. Five-ring or six-ring members were not found. These individual levels and types of PAHs are typical of marine environments with small oil-derived hydrocarbons inputs.

Compositional Analysis of Hydrocarbon Groups in Gasoline-Range Materials by Multidimensional SFC-Capillary GC

In the petroleum industry, the fluorescence indicator adsorption method (FIA) (ASTM D 1319) is often used for the analysis of saturates, olefins, and aromatics in gasoline-range materials. Unfortunately, this procedure is time consuming and suffers from a lack of precision and accuracy. For this reason, a more accurate and fully automated multidimensional supercritical fluid chromatography-capillary gas chromatography (SFC-GC) method is developed to characterize the hydrocarbon groups in base fuels originating from various gasoline refinery streams and feedstocks. The gasoline material is first separated into its fractions by SFC in order to determine the total aromatic and polynuclear aromatic content. Selective heartcutting is then used to transfer the desired gasoline peaks onto the GC where detailed information is collected to quantitate the individual hydrocarbon species within each class, including olefins. Nearly 25 test gasolines ranging from 4.0 to 34.0% (v/v) total olefins, originating from separate refineries, are analyzed.

Determination of Aromatic Hydrocarbons in Gasolines by Gas Chromatography/Fourier Transform Infrared Spectroscopy

The total aromatic contents of gasolines as well as 25 individual gasoline-range aromatic hydrocarbons were quantitated by GC/FT-IR with 1,2-dimethoxyethane as internal standard. Reconstructed selective wavelength chromatograms (SWCs) were used for each analyte to give good selectivities over respective coeluting hydrocarbons. Calibrations and quantitations were based on the peak areas from these SWCs, and all calibration curves were linear. An average relative standard deviation of 0.9% and an average accuracy of 0.9% were found. GC/FT-IR provided analyses comparable to the current EPA-specified GC/MS method with less sample preparation than GC/MS and with the added advantage of the simultaneous measurement of the ethers and alcohols (oxygenates) in the fuels.