946 resultados para Diesel emissions
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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This paper evaluates and quantifies the environmental impact from the use of some renewable fuels and fossils fuels in internal combustion engines. The following fuels are evaluated: gasoline blended with anhydrous ethyl alcohol (anhydrous ethanol), conventional diesel fuel, biodiesel in pure form and blended with diesel fuel, and natural gas. For the case of biodiesel, its complete life cycle and the closed carbon cycle (photosynthesis) were considered. The ecological efficiency concept depends on the environmental impact caused by CO(2), SO(2), NO(x) and particulate material (PM) emissions. The exhaust gases from internal combustion engines, in the case of the gasoline (blended with alcohol), biodiesel and biodiesel blended with conventional diesel, are the less polluting; on the other hand, the most polluting are those related to conventional diesel. They can cause serious problems to the environment because of their dangerous components for the human, animal and vegetable life. The resultant pollution of each one of the mentioned fuels are analyzed, considering separately CO(2), SO(2), NO(x) and particulate material (PM) emissions. As conclusion, it is possible to calculate an environmental factor that represents, qualitatively and quantitative, the emissions in internal combustion engines that are mostly used in urban transport. Biodiesel in pure form (B100) and blended with conventional diesel as fuel for engines pollute less than conventional diesel fuel. The ecological efficiency for pure biodiesel (B100) is 86.75%: for biodiesel blended with conventional diesel fuel (B20, 20% biodiesel and 80% diesel), it is 78.79%. Finally, the ecological efficiency for conventional diesel, when used in engines, is 77.34%; for gasoline, it is 82.52%, and for natural gas, it is 91.95%. All these figures considered a thermal efficiency of 30% for the internal combustion engine. Crown Copyright (C) 2008 Published by Elsevier Ltd. All rights reserved.
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We present the results of a study on vinyl bromide for the search for new far infrared (FIR) laser lines. As the pump source, we use a CW waveguide CO2 laser with a tunability of 290 MHz around each line in order to pump large offset vibrational transitions. As a consequence, we obtained 28 new FIR laser emissions; 24 of them have wavelengths greater than 500 mum and are, therefore, suitable to be used in high-field EPR spectroscopy, For each of the new lines, we give the wavelength, the offset of the pumping transition with respect to the center Frequency of the CO2 emission, the polarization relative to that of the pumping laser line, the operating pressure, and the relative intensity. We also present a catalog including data of all of the FIR laser lines observed from this molecule up to now.
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Produced water has lately aroused interest due to their high degree of salinity, suspended oil particles, chemicals added in various manufacturing processes, heavy metals and radioactivity sometimes. Along with oil and due to its high volume production, water production is one of the pollutants of most concern in the process of oil extraction. PAHs due to their ubiquity and their characteristics carcinogenic or mutagenic and teratogenic even have attracted the attention of every scientific society. Formed from the incomplete combustion of organic matter may be natural or anthropogenic. Some materials have been researched with the goal of cleaning up environmental matrices that may be contaminated by hydrocarbons. Among these materials researched various clays have been employed, of which highlights the vermiculite. The family of phyllosilicates, vermiculite for its potential and its high hydrophobic surface area has been a tool widely used in the decontamination of water in processes of oil spills. However, when it loses its capacity expanded hydrophobic having the necessity of using a hidrofobizante to make it organophilic. Among the numerous hidrofobizantes researched and used the linseed oil was the pioneer. In this study sought to evaluate the capacity of removal of PAHs using the vermiculite hydrofobized with linseed oil and wax also, for it was made use of the 24 full factorial design as the main tool for the experiments. We also evaluated the clay grain size (-20 +48 and -48 +80 #), the percentage of hidrofobizante applied (5 and 10%) and salinity of the water produced synthesized in our laboratory (35,000 and 55,000 ppm). The molecular fluorescence spectroscopy due to its sensitivity and speed was used to verify the adsorption capacity of clay, as well as gas chromatography served as an auxiliary technique to identify and quantify the PAHs in solution. In order to characterize the vermiculite was made use of X-ray fluorescence and X-ray diffraction. The infrared and thermogravimetry were essential to note hydrophobization and the amount of coating of clay. According to the fluorescence analysis showed that the test 12 was the best result in about 98% adsorption of fluorescent compounds, however the high salinity, the smallest particle size, the highest percentage of hidrofobizante and the use of linseed oil showed greater efficiency in the removal capacity of these hydrocarbons, in accordance with the trend followed by the analysis of the major factors of the factorial design. To verify the adsorption capacity of clay using a fixed volume of water produced synthetically, used as the test base 12, at their respective levels and factors. Thus, it was observed that after adding about 1 ½ liters of water solution produced synthetically, about 300 times its volume in mass, the vermiculite was able to adsorb 80% of fluorescent species present in solution
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Conselho Nacional de Desenvolvimento Científico e Tecnológico
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Combating pollution of soils is a challenge that has concerned researchers from different areas and motivated the search for technologies that aim the recovery of degraded soils. Literature shows numerous processes that have been proposed with the intent of remediating soils contaminated by oils and other by-products of the oil industry, considering that the processes available have, generally, high operating costs, this work proposes a costeffective alternative to the treatment of Diesel-contaminated soils. The washing solutions were prepared using water as aqueous phase, the saponified coconut oil (OCS) as surfactant and n-butanol as co-surfactant. In this study, the soil was characterized by physical and chemical analyses. The study of diesel desorption from the soil was held in bath, using hexane and washing solutions, which had 10 and 20 wt.% active matter (AM - co-surfactant/surfactants) respectively. The study of the influence of active matter concentration and temperature in bath agitated used an experimental planning. The experiment also developed a system of percolation in bed to wash the soil and studied the influence of the concentration of active substance and volume of washing solution using an experimental planning. The optimal times to achieve hexane extraction were 30 and 180 min, while the best results using a 10% AM was 60 min and using a 20% AM was 120 min. The results of the experimental planning on bath showed that the maximum diesel removal was obtained when at a 20 wt.% of AM and under 50 °C, removing 99.92% of the oil. As for experiments in the system of percolation soil bed, the maximum diesel removal was high when the volume of the washing solution was of 5 L and the concentration of 20% AM. This experiment concluded that the concentration of AM and the temperature were vital to bath experiments for diesel removal, while in the system of percolation soil bed only concentration of AM influenced the soil remediation
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The oxidative desulfurization process (ODS) of a commercial diesel fuel was performed under mild conditions in the presence of catalysts based on vanadium or manganese, supported on alumina, clays (commercial, natural and pillared) and zeolites (NaX, NaY, beta, mordenite and ZSM-5). The catalysts were synthesized by wet impregnation and characterized by X-ray diffraction, textural analysis by N2 adsorption and scanning electron microscopy. The dibenzothiophene (DBT) was used as sulfur compound in catalytic evaluation. The reactions were performed using acetonitrile as solvent and the hydrogen peroxide as oxidant at 55°C. The reaction products were analized by gas chromatography (GC-FID). In the studied conditions, the process was efficient due to the DBT was converted to its corresponding sulfone. Both DBT and corresponding sulfone were extracted by the solvent. Removals and oxidations up to 100% of sulfur compound were achieved. The catalysts supported on ZSM-5 zeolite showed are more effective for oxidation reaction of sulfur compound, presenting the best results. It was observed for oxidation reaction, that vanadium catalysts were more effective and manganese catalysts showed best results for removal of sulfur compounds
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Muitos mecanismos provocados pela ação humana vêm gerando um aumento na queima de combustíveis fósseis e processos químicos (produtos orgânicos, carvão, madeira, óleo diesel, gasolina e outros derivados de petróleo) e, consequentemente, há um aumento na emissão de CO2 na atmosfera. Uma das alternativas para a captura desse poluente é o processo de adsorção, o qual pode ajudar na redução do CO2. As hidrotalcitas ou hidróxidos duplos lamelares (HDL s) estão dentre esses materiais estudados, já que apresentam alta estabilidade e uma boa porosidade, tornando-se assim um promissor adsorvente de gases poluentes. Os HDL s formam um grupo de argilas do tipo aniônico que consiste em camadas positivamente carregadas de óxido de metal (ou hidróxido de metal) com intercamadas de ânions. Foi constatado que ânions que possuem duas cargas negativas, estabilizam muito mais que ânions monovalentes, sendo o carbonato o mais estável dos ânions divalentes. Neste trabalho, foi proposta uma modificação na síntese direta através da co-precipitação a pH constante utilizando sais de cátions divalentes (Mg2+) e trivalentes (Al3+) reportados na literatura. Durante a síntese dos HDL s retirou-se o carbonato, bem como, utilizou-se um copolímero como um template para o alargamento das lamelas. As amostras foram caracterizadas utilizando as técnicas de DRX, TG/DTG, FTIR, MEV/EDX, MET e adsorção e dessorção de N2. Os dados obtidos indicam que a estrutura, mesmo após a modificação, apresentou resultados condizentes com os encontrados na literatura. Dentre as várias aplicações dos HDL s foi realizado o estudo da adsorção do CO2. A capacidade de adsorção do material foi testada de acordo com o tempo de contato entre o adsorvente e o adsorbato, sendo esperado que os materiais tratados com template apresentassem um maior desempenho
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In order to obtain a biofuel similar to mineral diesel, lanthanum-incorporated SBA- 15 nanostructured materials, LaSBA-15(pH), with different Si/La molar ratios (75, 50, 25), were synthesized in a two-steps hydrothermal procedure, with pH-adjusting of the synthesis gel at 6, and were used like catalytic solids in the buriti oil thermal catalytic cracking. These solids were characterized by X-ray fluorescence (XRF), powder X-ray diffraction (XRD), thermogravimetric analysis (TG/DTG), infrared spectroscopy (FTIR), nitrogen porosimetry and ethanol dehydration, aiming to active sites identify. Taken together, the analyses indicated that the synthesis method has employed to obtain materials highly ordered mesostructures with large average pore sizes and high surface area, besides suggested that the lanthanum was incorporated in the SBA-15 both into the framework as well as within the mesopores. Catalytic dehydration of ethanol over the LaSBA-15(pH) products has shown that they have weak Lewis acid and basic functionalities, indicative of the presence of lanthanum oxide in these samples, especially on the La75SBA-15(pH) sample, which has presented the highest selectivity to ethylene. The buriti oil thermal and thermal catalytic cracking, realized from the room temperature to 450 ºC in a simple distillation system, has allowed obtaining two liquid fractions, each consisting of two phases, one aqueous and another organic, organic liquid (OL). The OL obtained from first fractions has shown high acid index, even in the thermal catalytic process. One the other hand, OL coming from second ones, called green diesel (GD), have presented low acid index, particularly that one obtained from the thermal catalytic process realized over LaSBA-15(pH) samples. The acid sites presence in these samples, associated to their large average pore sizes and high surface areas, have allowed them, especially the La75SBA-15(pH), to present deoxygenating activity in the buriti oil thermal catalytic cracking, providing an oxygenates content reduction, particularly carboxylic acids, in the GD. Furthermore, the GD comes from the second liquid fraction obtained in the buriti oil thermal catalytic cracking over this latest solid sample has shown hydrocarbons composition and physic-chemical properties similar to that mineral diesel, beyond sulfur content low
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)