Simultaneous determination of quinoline and pyridine compounds in gasoline and diesel by differential pulse voltammetry

The presence of trace basic organonitrogen compounds such as quinoline and pyridine in derivative petroleum fuels plays an important role in maintaining the engines of vehicles. However, these substances can contaminate the environment and so must be controlled because most of them are potentially carcinogenic and mutagenic. For these reasons, a reliable and sensitive method was developed for the determination of basic nitrogen compounds in fuel samples such as gasoline and diesel. This method utilizes preconcentration on an ion-exchange resin (Amberlyte IR - 120 H) followed by differential pulse voltammetry (DPV) on a glassy carbon electrode. The electrochemical behavior of quinoline and pyridine as studied by cyclic voltammetry (CV) suggests that their reduction occurs via a reversible electron transfer followed by an irreversible chemical reaction. Very well resolved diffusion-controlled voltammetric peaks were obtained in dimethylformamide (DMF) with tetrabutylammonium tetrafluoroborate (TBAF(4) 0.1 mol L-1) for quinoline (-1.95 V) and pyridine (-2.52 V) vs. Ag vertical bar AgCl vertical bar KClsat reference electrode. The proposed DPV method displayed a good linear response from 0.10 to 300 mg L-1 and a limit of detection (LOD) of 5.05 and 0.25 mu g L-1 for quinoline and pyridine, respectively. Using the method of standard additions, the simultaneous determination of quinoline and pyridine in gasoline samples yielded 25.0 +/- 0.3 and 33.0 +/- 0.7 mg L-1 and in diesel samples yielded 80.3 +/- 0.2 and 131 +/- 0.4 mg L-1, respectively. Spike recoveries were 94.4 +/- 0.3% and 10 +/- 0.5% for quinoline and pyridine, respectively, in the fuel determinations. This proposed method was also compared with UV-vis spectrophotometric measurements. Results obtained for the two methods agreed well based on F and t student's tests.

Simultaneous determination of neutral nitrogen compounds in gasoline and diesel by differential pulse voltammetry

The presence of trace neutral organonitrogen compounds as carbazole and indole in derivative petroleum fuels plays an important role in the car's engine maintenance. In addition, these substances contribute to the environmental contamination and their control is necessary because most of them are potentially carcinogenic and mutagenic. For those reasons, a reliable and sensitive method was proposed for the determination of neutral nitrogen compounds in fuel samples, such as gasoline and diesel using preconcentration with modified silica gel (Merck 70-230 mesh ASTM) followed by differential pulse voltammetry (DPV) technique on a glassy carbon electrode. The electrochemical behavior of carbazole and indole studied by cyclic voltammetry (CV) suggests that their reduction occurs via a reversible electron transfer followed by an irreversible chemical reaction. Very well resolved diffusion controlled voltammetric peaks were obtained in dimethylformamide (DMF) with tetrabutylammonium tetrafluoroborate (TBAF(4) 0.1 mol L-1) for indole (-2.27 V) and carbazole (-2.67 V) versus Ag vertical bar AgCl vertical bar KClsat reference electrode. The proposed DPV method showed a good linear response range from 0.10 to 300 mg L-1 and a limit of detection (L.O.D) of 7.48 and 2.66 mu g L-1 for indole and carbazole, respectively. The results showed that simultaneous determination of indole and carbazole presents in spiked gasoline samples were 15.8 +/- 0.3 and 64.6 +/- 0.9 mg L-1 and in spiked diesel samples were 9.29 +/- 1 and 142 +/- 1 mg L-1, respectively. The recovery was evaluated and the results shown the values of 88.9 +/- 0.4 and 90.2 +/- 0.8% for carbazole and indole in fuel determinations. The proposed method was also compared with UV-vis spectrophotometric measures and the results obtained for the two methods were in good agreement according to the F and t Student's tests. (C) 2007 Elsevier B.V. All rights reserved.

Desenvolvimento de métodos eletroanalíticos para determinação de compostos nitrogenados em combustíveis derivados do petróleo

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

An Intelligent System for Petroleum Well Drilling Cutting Analysis

Cutting analysis is a important and crucial task task to detect and prevent problems during the petroleum well drilling process. Several studies have been developed for drilling inspection, but none of them takes care about analysing the generated cutting at the vibrating shale shakers. Here we proposed a system to analyse the cutting's concentration at the vibrating shale shakers, which can indicate problems during the petroleum well drilling process, such that the collapse of the well borehole walls. Cutting's images are acquired and sent to the data analysis module, which has as the main goal to extract features and to classify frames according to one of three previously classes of cutting's volume. A collection of supervised classifiers were applied in order to allow comparisons about their accuracy and efficiency. We used the Optimum-Path Forest (OPF), Artificial Neural Network using Multi layer Perceptrons (ANN-MLP), Support Vector Machines (SVM) and a Bayesian Classifier (BC) for this task. The first one outperformed all the remaining classifiers. Recall that we are also the first to introduce the OPF classifier in this field of knowledge. Very good results show the robustness of the proposed system, which can be also integrated with other commonly system (Mud-Logging) in order to improve the last one's efficiency.

Biodiesel CO2 emissions: A comparison with the main fuels in the Brazilian market

The use of biodiesel is increasing as an attractive fuel due to the depleting fossil fuel resources and environmental degradation. This paper presents results of an investigation on the potentials of biodiesel as an alternative fuel and main substitute of diesel oil, comparing the CO2 emissions of the main fuels in the Brazilian market with those of biodiesel, in pure form or blended in different proportions with diesel oil (2%, 5%, and 20%, called B2, B5, and B20, respectively). The results of the study are shown in ton CO2 per m(3) and ton CO2 per year of fuel. The fuels were analyzed considering their chemical composition, stoichiometric combustion parameters and mean consumption for a single vehicle. The fuels studied were: gasoline, diesel oil, anhydrous ethyl alcohol (anhydrous ethanol), and biodiesel from used frying oil and from soybean oil. For the case of biodiesel, its complete life cycle and the closed carbon cycle (photosynthesis) were considered. With data provided by the Brazilian Association of Automotive Vehicle Manufacturers (ANFAVEA) for the number of vehicles produced in Brazil, the emissions of CO2 for the national fleet in 2007 were obtained per type of fuel. With data provided by the Brazilian Department of Transit (DENATRAN) concerning the number of diesel vehicles in the last five years in Brazil, the total CO2 emissions and the percentage that they would decrease in the case of use of pure biodiesel, B100, or several mixtures, B2, B5 and B20, were calculated. Estimates of CO2 emissions for a future scenario considering the mixtures B5 and B20 are also included in this article. Crown Copyright (C) 2008 Published by Elsevier B.V. All rights reserved.

Action mechanisms of petroleum hydrocarbons present in waters impacted by an oil spill on the genetic material of Allium cepa root cells

Chromosomal aberration (CA) assays have been widely used, not only to assess the genotoxic effects of chemical agents, but also to evaluate their action mechanisms on the genetic material of exposed organisms. This is of particular interest, since such analyses provide a better knowledge related to the action of these agents on DNA. Among test organisms, Allium cepa is an outstanding species due to its sensitivity and suitable chromosomal features, which are essential for studies on chromosomal damage or disturbances in cell cycle. The goal of the present study was to analyze the action mechanisms of chemical agents present in petroleum polluted waters. Therefore, CA assay was carried out in A. cepa meristematic cells exposed to the Guaeca river waters, located in the city of Sao Sebastiao, SP, Brazil, which had its waters impacted by an oil pipeline leak. Analyses of the aberration types showed clastogenic and aneugenic effects for the roots exposed to the polluted waters from Guaeca river, besides the induction of cell death. Probably all the observed effects were induced by the petroleum hydrocarbons derived from the oil leakage. (C) 2008 Elsevier B.V. All rights reserved.

Induction of micronucleus and nuclear alterations in fish (Oreochromis niloticus) by a petroleum

In this study, micronucleus and nuclear alterations tests were performed on erythrocytes of Oreochromis niloticus (Perciformes, Cichlidae) in order to evaluate the water quality of the Atibaia river, in an area that receives effluents discharge of a petroleum refinery and also to evaluate the effectiveness of the treatments used by the refinery. Water samples were collected in five different sites related with a refinery from São Paulo State, Brazil. For the micronucleus and nuclear alterations tests, O. niloticus specimens were exposed for 72 h to the water samples and in pure ground water (negative control). The results herein obtained indicated that the treatments used by the refinery diminished the cytogenetic damage; however they were not fully effective, since the final mill has induced damages in the genetic material of the test organism. (C) 2008 Elsevier B.V. All rights reserved.

Micronucleus and chromosome aberrations induced in onion (Allium cepa) by a petroleum refinery effluent and by river water that receives this effluent

In this study, micronucleus (MN) and chromosome aberration (CA) tests in Allium cepa (onion) were carried out in order to make a preliminary characterization of the water quality of the Atibaia River in an area that is under the influence of petroleum refinery and also to evaluate the effectiveness of the treatments used by the refinery. For these evaluations, seeds of A. cepa were germinated in waters collected in five different sites related with the refinery in ultra-pure water (negative control) and in methyl methanesulfonate solution (positive control). According to our results, we can suggest that even after the treatments (physicochemical, biological and stabilization pond) the final refinery effluent could induce chromosome aberrations and micronucleus in meristematic cells of A. cepa and that the discharge of the petroleum refinery effluents in the Atibaia River can interfere in the quality of this river. (C) 2009 Elsevier B.V. All rights reserved.

Chromosome aberration and micronucleus frequencies in Allium cepa cells exposed to petroleum polluted water - A case study

In the present study, we applied Chromosome Aberration (CA) and Micronucleus (MN) tests to Allium cepa root cells, in order to evaluate the water quality of Guaeca river. This river, located in the city of Sao Sebastiao, SP, Brazil, had been affected by an oil pipeline leak. Chemical analyses of Total Petroleum Hydrocarbons (TPHs) and Polycyclic Aromatic Hydrocarbons (PAHs) were also carried out in water samples, collected in July 2005 (dry season) and February 2006 (rainy season) in 4 different river sites. The largest CA and MN incidence in the meristematic cells of A. cepa was observed after exposure to water sample collected during the dry season, at the spring of the river, where the oil leak has arisen. The F, cells from roots exposed to such sample (non-merismatic region) were also analyzed for the incidence of MN, showing a larger frequency of irregularities, indicating a possible development of CA into MN. Lastly, our study reveals a direct correlation between water chemical analyses (contamination by TPHs and PAHs) and both genotoxic and mutagenic effects observed in exposed A. cepa cells. (C) 2007 Elsevier B.V. All rights reserved.

BTEX biodegradation by bacteria from effluents of petroleum refinery

Groundwater contamination with benzene, toluene, ethylbenzene and xylene (BTEX) has been increasing, thus requiring an urgent development of methodologies that are able to remove or minimize the damages these compounds can cause to the environment. The biodegradation process using microorganisms has been regarded as an efficient technology to treat places contaminated with hydrocarbons, since they are able to biotransform and/or biodegrade target pollutants. To prove the efficiency of this process, besides chemical analysis, the use of biological assessments has been indicated. This work identified and selected BTEX-biodegrading microorganisms present in effluents from petroleum refinery, and evaluated the efficiency of microorganism biodegradation process for reducing genotoxic and mutagenic BTEX damage through two test-systems: Allium cepa and hepatoma tissue culture (HTC) cells. Five different non-biodegraded BTEX concentrations were evaluated in relation to biodegraded concentrations. The biodegradation process was performed in a BOO Trak Apparatus (HACH) for 20 days, using microorganisms pre-selected through enrichment. Although the biodegradation usually occurs by a consortium of different microorganisms, the consortium in this study was composed exclusively of five bacteria species and the bacteria Pseudomonas putida was held responsible for the BTEX biodegradation. The chemical analyses showed that BTEX was reduced in the biodegraded concentrations. The results obtained with genotoxicity assays, carried out with both A. cepa and HTC cells, showed that the biodegradation process was able to decrease the genotoxic damages of BTEX. By mutagenic tests, we observed a decrease in damage only to the A. cepa organism. Although no decrease in mutagenicity was observed for HTC cells, no increase of this effect after the biodegradation process was observed either. The application of pre-selected bacteria in biodegradation processes can represent a reliable and effective tool in the treatment of water contaminated with BTEX mixture. Therefore, the raw petroleum refinery effluent might be a source of hydrocarbon-biodegrading microorganisms. (c) 2010 Elsevier B.A. All rights reserved.

Glycerol: A promising and abundant carbon source for industrial microbiology

Petroleum is the main energy source utilized in the world, but its availability is limited and the search for new renewable energy sources is of major interest. Biofuels, such as ethanol and biodiesel, are among the most promising sources for the substitution of fossil fuels. Biodiesel can replace petroleum diesel, as it is produced from animal fats and vegetable oils, which generate about 10% (w/w) glycerol as the main by-product. The excess glycerol generated may become an environmental problem. since it cannot be disposed of in the environment. One of the possible applications is its use as carbon and energy source for microbial growth in industrial microbiology. Glycerol bioconversion in valuable chemicals, such as 1,3-propanediol, dihydroxyacetone, ethanol, succinate etc. is discussed in this review article. (C) 2008 Elsevier B.V. All rights reserved.

Artificial immune systems for classification of petroleum well drilling operations

This paper presents two approaches of Artificial Immune System for Pattern Recognition (CLONALG and Parallel AIRS2) to classify automatically the well drilling operation stages. The classification is carried out through the analysis of some mud-logging parameters. In order to validate the performance of AIS techniques, the results were compared with others classification methods: neural network, support vector machine and lazy learning.

Petroleum well drilling monitoring through cutting image analysis and artificial intelligence techniques

Petroleum well drilling monitoring has become an important tool for detecting and preventing problems during the well drilling process. In this paper, we propose to assist the drilling process by analyzing the cutting images at the vibrating shake shaker, in which different concentrations of cuttings can indicate possible problems, such as the collapse of the well borehole walls. In such a way, we present here an innovative computer vision system composed by a real time cutting volume estimator addressed by support vector regression. As far we know, we are the first to propose the petroleum well drilling monitoring by cutting image analysis. We also applied a collection of supervised classifiers for cutting volume classification. (C) 2010 Elsevier Ltd. All rights reserved.

Determination of labile barium in petroleum-produced formation water using paper-based DGT samplers

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Experimental aspects of biomass fuels in a bubbling fluidized bed combustor

This work presents experimental information relevant to the combustion of biomass in a bubbling fluidized bed. The biomass distribution in a fluidized bed was studied through tests performed in a cold bed, while the volatiles released in the biomass pyrolysis, the burning rate of the resulting charcoal, and the combustion control regime, were studied through tests performed in a high temperature bed.Visual examination of photographs taken from a transparent walls bed, with a rectangular cross-section, showed that the large fuel particles, typical of biomass processing, were distributed in the bubbles, in the splash zone, and in the emulsion phase. The occurrence of biomass in the emulsion phase was favored by burning biomass particles of greater density and smaller size-expetimentally determined in each case. Decreasing the fuel particle size improved the biomass distribution inside the bed. The same was accomplished by increasing the superficial gas velocity as high as possible, compatibly with the acceptable elutriation.Burning tests showed that the biomass fuels have the advantage of reaching the diffusional regime at temperatures that can be lower than 1000 K, which ensures that the biomass fuels burn in a stable regime. (C) 2007 Elsevier B.V. All rights reserved.