Análise das emissões atmosféricas por veículos automotores em Natal-RN

The fast urban occupation of Brazil, mainly from the last decade of 50, a sensible degradation of the quality of the air generated mainly for the activities was verified human beings associates to industrialization. From the past years, the situation has gotten worst in function of the increment of the fleet of vehicles in circulation in the great cities. Being these, in the city of Natal-RN, the ones that offer the biggest contributions to the atmospheric pollution. For atmospheric air to be a finite natural resources, indispensable and essential to the maintenance of the life in the land, is necessary to the implementation of action to improve its quality and to protect the health of the population. With the objective to study relative aspects to the characteristics of vehicles in use, the present study it searchs to analyze the levels of emissions of gases generated for vehicles converted bi-fuels into the modalities: natural gas (GNV), gasoline and alcohol, inspected for ends of register and together licensing to the State Department of Transit. One used the data gotten from inspections carried through for the company System Specialized in Inspection To propagate, in the city of the Natal-RN, capital of the State of Rio Grande do Norte, between 14 of November of 2003 and 30 of December of 2004. The analyzed parameters are established in the resolution nº 07/93 CONAMA. Of a total of 1.517 inspected vehicles, a average of 15,2% of failed was gotten, or either, that they emit levels of pollution above of the limits established for the legislation, below of the national average that is of 20,0%. The analysis of the data discloses that 7.3% of the fleet are converted the GNV; the growth of vehicles converted the GNV into the city is gradual, with a average of increment in last the 4 years of 23,3%; it has a vehicle predominance that has as combustible original to the gasoline (88,2%); the inspected fleet has average age of 8 years of use, considered young for the Brazilian standards, except for the moved one to the alcohol (average of use of 15 years). Moreover, the type of fuel is not the main parameter to define the indices of emissions; the age of the fleet is the parameter most important when emission is analyzed to propagate; the gas that more generates failed in the inspections is the corrected carbon monoxide; the vehicles generate higher indices of emissions in idling for all the fuels; the presence of the catalyser was not reflected, as it expected, in the reduction of emissions of gases toxic, however when analyzed according to year of manufacture, it was observed that for the vehicles manufactured between 1997 and 2004, reduction of 46,0% in the failed of the vehicles equipped with catalyser was gotten. In conclusion, the fleet of the studied sample, in average terms, takes care of to the requirements of Resolution CONAMA nº 07/93. The results gotten for the present study can subsidize action of public administrations that aim at to the improvement and the maintenance of the quality of air in the city of Natal-RN, as, for example, to implant a net of monitoramento of the quality of air

Síntese, caracterização e aplicação de MCM-41 funcionalizado com diisopropilamina no processo de adsorção do dióxido de carbono

Emissions of CO2 in the atmosphere have increased successively by various mechanisms caused by human action, especially as fossil fuel combustion and industrial chemical processes. This leads to the increase in average temperature in the atmosphere, which we call global warming. The search for new technologies to minimize environmental impacts arising from this phenomenon has been investigated. The capture of CO2 is one of the alternatives that can help reduce emis ions of greenhouse gases. The CO2 can be captured through the process of selective adsorption using adsorbents for this purpose. Were synthesized by hydrothermal method, materials of the type MCM-41 and Al-MCM-41 in the molar ratio Si / Al equal to 50. The synthesis of gels were prepared from a source of silicon, sodium, water and aluminum in the case of Al-MCM-41. The period of synthesis of the materials was 5 days in autoclave at 100°C. After that time materials were filtered, washed and dried in greenhouse at 100 º C for 4 hours and then calcined at 450 º C. Then the calcined material was functionalized with the Di-isopropylamine (DIPA) by the method of wet impregnation. We used 0.5 g of material mesopores to 3.5 mL of DIPA. The materials were functionalized in a closed container for 24 hours, and after this period were dried at brackground temperature for 2 hours. Were subsequently subjected to heat treatment at 250°C for 1 hour. These materials were used for the adsorption of CO2 and were characterized by XRD, FT-IR, BET / BJH, SEM, EDX and TG / DTG. Tests of adsorption of CO2 was carried out under the following conditions: 100 mg of adsorbent, temperature of 75°C under flow of 100 mL/min of CO2 for 2 hours. The desorption of CO2 was carried out by thermogravimetry from ambient temperature to 900ºC under flow of 25 mL min of He and a ratio of 10ºC/min. The difratogramas X-ray for the synthesized samples showed the characteristic peaks of MCM-41, showing that the structure of it was obtained. For samples functionalized there was a decrease of the intensities of these peaks, with a consequent reduction in the structural ordering of the material. However, the structure was preserved mesopores. The adsorption tests showed that the functionalized MCM-41 is presented as a material promising adsorbent, for CO2 capture, with a loss of mass on the desorption CO2 of 7,52%, while that in Al-MCM- 41 functionalized showed no such loss

Estudo de materiais mesoporosos funcionalizados com diferentes aminas para captura do dióxido de carbono através do processo de adsorção

Intensive use of machinery and engines burning fuel dumps into the atmosphere huge amounts of carbon dioxide (CO2), causing the intensification of the greenhouse effect. Climate changes that are occurring in the world are directly related to emissions of greenhouse gases, mainly CO2, gases, mainly due to the excessive use of fossil fuels. The search for new technologies to minimize the environmental impacts of this phenomenon has been investigated. Sequestration of CO2 is one of the alternatives that can help minimize greenhouse gas emissions. The CO2 can be captured by the post-combustion technology, by adsorption using adsorbents selective for this purpose. With this objective, were synthesized by hydrothermal method at 100 °C, the type mesoporous materials MCM - 41 and SBA-15. After the synthesis, the materials were submitted to a calcination step and subsequently functionalized with different amines (APTES, MEA, DEA and PEI) through reflux method. The samples functionalized with amines were tested for adsorption of CO2 in order to evaluate their adsorption capacities as well, were subjected to various analyzes of characterization in order to assess the efficiency of the method used for functionalization with amines. The physic-chemical techniques were used: X- ray diffraction (XRD), nitrogen adsorption and desorption (BET/BJH), scanning electron microscopy (SEM), transmission electron microscopy (TEM), CNH Analysis, Thermogravimetry (TG/DTG) and photoelectron spectroscopy X-ray (XPS). The CO2 adsorption experiments were carried out under the following conditions: 100 mg of adsorbent, at 25 °C under a flow of 100 ml/min of CO2, atmospheric pressure and the adsorption variation in time 10-210 min. The X-ray diffraction with the transmission electron micrographs for the samples synthesized and functionalized, MCM-41 and SBA-15 showed characteristic peaks of hexagonal mesoporous structure formation, showing the structure thereof was obtained. The method used was efficient reflux according to XPS and elemental analysis, which showed the presence of amines in the starting materials. The functionalized SBA -15 samples were those that had potential as best adsorbent for CO2 capture when compared with samples of MCM-41, obtaining the maximum adsorption capacity for SBA-15-P sample

Os reservatórios eutrofizados da região tropical semiárida atuam como emissores ou como sequestradores de dióxido de carbono?

The aquatic ecosystems can play a role as carbon-dioxide-source or carbon-dioxide-sink systems due to the high predominance of heterotrophic or autotrophic metabolism. The primary production can strongly affect the carbon balance (CO2) through the consumption of carbon dioxide in the photosynthesis, especially in eutrophic environment, acting as a carbon sink. The present study tested the hypothesis that the eutrophic reservoirs in tropical semi-arid region are carbon dioxide-sink systems due to the high primary productivity presented in these systems. Five Brazilian reservoirs from the semi-arid in the northeast region were monitored monthly during four years (2010 to 2013) with a prolonged drought event identified during the study. The results showed an increasing level of eutrophication over the period of prolonged drought, with the predominance of autotrophy. Significant negative correlations were observed between the partial pressure of CO2 (pCO2) (p<0,001) and chlorophyll-a in the Boqueirão, Passagem das Traíras, Dourado and Gargalheiras reservoirs, showing a pattern of the carbon dioxide-sink systems. However, this pattern was not found in Cruzeta reservoir. In summary, in the tropical semi-arid region, hydrological and morphometric variables can lead to different behaviors of the water-supply reservoirs on the carbon metabolism. The eutrophic reservoirs evaluated showed a negative relationship between pCO2 and Chl-a, which suggests that these water bodies show an autotrophic metabolism and behave as carbon dioxide- sink systems

Hidróxidos duplos lamelares de magnésio e alumínio modificados com carbonato e p123 para adsorção de dióxido de carbono

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

Síntese hidrotérmica e caracterização estrutural de titanatos nanotubulares para aplicação na captura do dióxido de carbono

Nanostructured materials have been spreading successfully over past years due its size and unusual properties, resulting in an exponential growth of research activities devoted to nanoscience and nanotechnology, which has stimulated the search for different methods to control main properties of nanomaterials and make them suitable for applications with high added value. In the late 90 s an alternative and low cost method was proposed from alkaline hydrothermal synthesis of nanotubes. Based on this context, the objective of this work was to prepare different materials based on TiO2 anatase using hydrothermal synthesis method proposed by Kasuga and submit them to an acid wash treatment, in order to check the structural behavior of final samples. They were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), adsorption/desorption of N2, thermal analysis (TG/DTA) and various spectroscopic methods such as absorption spectroscopy in the infrared (FT-IR), Raman spectroscopy and X-ray photoelectron spectroscopy (XPS). All the information of characterizations confirmed the complete conversion of anatase TiO2 in nanotubes titanates (TTNT). Observing the influence of acid washing treatment in titanates structure, it was concluded that the nanotubes are formed during heat treatment, the sample which was not subjected to this process also achieved a complete phase transformation, as showed in crystallography and morphology results, however the surface area of them practically doubled after the acid washing. By spectroscopy was performed a discussion about chemical composition of these titanates, obtaining relevant results. Finally, it was observed that the products obtained in this work are potential materials for various applications in adsorption, catalysis and photocatalysis, showing great promise in CO2 capture

Poluentes atmosféricos: monóxido e dióxido de carbono no nordeste do Brasil

The interference of man in the middle atmosphere can be evidenced by the presence of carbon monoxide, gas associated with burning fossil fuels and carbon dioxide content, essential for respiration of plants and thermal balance of the Earth. In this thesis we initially evaluated the intensity of the spatial distribution of carbon monoxide in the Northeast of Brazil, and subsequently the behavior of temporal variations of the pollutants carbon monoxide and carbon dioxide in the atmospheric boundary layer Maxaranguape / RN. Research has shown that, driven by speculation and promoting the occupation of land for agriculture, cattle ranching and tourism in the Northeast of Brazil, the changes established by the man in the middle geomorphological affect the lower troposphere on a large scale, with a predominance of concentrations in central Pernambuco, Paraiba's south-central and central-west of Alagoas. However, the study of Maxaranguape / RN results showed little variation in carbon monoxide and carbon dioxide, with the speed of the wind persisting with values greater than 7.8 m / s, showing dispersion and diffusion of pollutants which resulted in faster renewal of local atmospheric air

Avaliação da dolomita funcionalizada para remoção de H2S em gás natural

The natural gas is an alternative source of energy which is found underground in porous and permeable rocks and being associated or not to the oil. Its basic composition includes methane, other hydrocarbon and compounds such as carbon dioxide, nitrogen, sulphidric gas, mercaptans, water and solid particles. In this work, the dolomite mineral, a double carbonate of calcium and magnesium whose the chemical formula is CaMg(CO3)2, was evaluated as adsorbent material. The material was characterized by granulometric analysis, X-ray fluorescence, X-ray diffraction, thermogravimetric analysis, differential thermal analysis, specific surface area, porosity, scanning electronic microscopy and infrared spectroscopy. Then the material was functionalized with diethanolamine (dolomite+diethanolamine) and diisopropylamine (dolomite+diisopropylamine). The results indicated that the adsorbents presented appropriate physiochemical characteristics for H2S adsorption. The adsorption tests were accomplished in a system coupled to a gas chromatograph and the H2S monitoring in the output of the system was accomplished by a pulsed flame photometric detector (PFPD). The adsorbents presented a significant adsorption capacity. Among the analyzed adsorbents, the dolomite+diethanolamine presented the best capacity of adsorption. The breakthrough curves obtained proved the efficiency of this process

Avaliação de heterociclo do tipo mesoiônico solubilizado em sistema microemulsionado para aplicação em dutos

The efficiency of inhibition to corrosion of steel AISI 1018 of surfactant coconut oil saponified (SCO) and heterocyclic type mesoionics (1,3,4-triazólio-2-tiolato) in systems microemulsionados (SCO-ME and SCO-ME-MI) Of type O/A (rich in water emulsion) region with the work of Winsor IV. The systems microemulsionados (SCO-ME and SCO-ME-MI) were evaluated with a corrosion inhibitor for use in saline 10,000 ppm of chloride enriched with carbon dioxide (CO2). The assessment of corrosion inhibitors were evaluated by the techniques of linear polarization resistance (LPR) and loss of weight (MW) in a cell instrumented given the gravity and electrochemical devices. The systems were shooting speed of less than 60 minutes and efficiency of inhibition [SCO-ME (91.25%) and SCO-ME-MI (98.54%)]

Análise do desempenho de um queimador infravermelho funcionando com gás liquefeito de petróleo e glicerina

The use of infrared burners in industrial applications has many advantages in terms of technical-operational, for example, uniformity in the heat supply in the form of radiation and convection, with greater control of emissions due to the passage of exhaust gases through a macro-porous ceramic bed. This paper presents an infrared burner commercial, which was adapted an experimental ejector, capable of promoting a mixture of liquefied petroleum gas (LPG) and glycerin. By varying the percentage of dual-fuel, it was evaluated the performance of the infrared burner by performing an energy balance and atmospheric emissions. It was introduced a temperature controller with thermocouple modulating two-stage (low heat / high heat), using solenoid valves for each fuel. The infrared burner has been tested and tests by varying the amount of glycerin inserted by a gravity feed system. The method of thermodynamic analysis to estimate the load was used an aluminum plate located at the exit of combustion gases and the distribution of temperatures measured by a data acquisition system which recorded real-time measurements of the thermocouples attached. The burner had a stable combustion at levels of 15, 20 and 25% of adding glycerin in mass ratio of LPG gas, increasing the supply of heat to the plate. According to data obtained showed that there was an improvement in the efficiency of the 1st Law of infrared burner with increasing addition of glycerin. The emission levels of greenhouse gases produced by combustion (CO, NOx, SO2 and HC) met the environmental limits set by resolution No. 382/2006 of CONAMA

Estudo da injeção de CO2 em reservatórios carbonáticos de dupla-porosidade

As rochas carbonáticas ocupam, numa visão global, um expressivo volume da crosta terrestre. De maneira geral, pode-se dizer que essas rochas estão presentes nas diversas unidades litoestatigráficas da Terra. Os reservatórios carbonáticos são reservas naturalmente fraturadas que exigem uma abordagem diferenciada na modelagem em programas de simulação numérica. Os modelos de dupla porosidade são descritos por funções de tranferências que modelam o fluxo de óleo entre matriz e fraturas. Em um reservatório carbonático naturalmente fraturado o sistema de fraturas é determinante no escoamento de fluidos dentro da reserva. Os maiores reservatórios carbonáticos do mundo estão situados no Oriente Médio e na América do Norte. As maiores reservas de óleo brasileiras encontradas neste tipo de reservatório estão localizadas nos campos do Pré-Sal. No Pré-Sal, um volume significativo de dióxido de carbono é produzido juntamente com o óleo. A disponibilidade de um volume consideravél de dióxido de carbono derivado da produção de óleo no Pré-Sal favorece a utilização dos processos de EOR (Enhanced Oil Recovery) por injeção de gás. O processo de injeção de dióxido de carbono vem sendo utilizado em uma grande quantidade de projetos pelo mundo. A afinidade existente entre o óleo e o dióxido de carbono causa uma frente miscível entre as duas fases causando inchamento e vaporização do óleo dentro do reservatório. Para o estudo, foi utilizado um modelo base de reservatório de dupla-porosidade, desenvolvido pela CMG para o 6° Projeto de Soluções Comparativas da SPE, que modela sistemas de fraturas e de matriz e a tranferência de massa fluida entre elas, características de reservatórios naturalmente fraturados. Foi feita uma análise da injeção de diferentes vazões de dióxido de carbono no modelo base e em modelos semelhantes, com aumento e redução de 5 e 0.5 pontos nas propriedades de porosidade e permeabilidade da matriz, respectivamente, tendo a produção de óleo como resultado. A injeção de 25 milhões de pés cúbicos por dia de CO2 foi a vazão que obteve a melhor fator de recuperação

Análise de viabilidade de injeção de fluidos alternativos ao vapor em reservatórios de óleo pesado

Many of hydrocarbon reserves existing in the world are formed by heavy oils (°API between 10 and 20). Moreover, several heavy oil fields are mature and, thus, offer great challenges for oil industry. Among the thermal methods used to recover these resources, steamflooding has been the main economically viable alternative. Latent heat carried by steam heats the reservoir, reducing oil viscosity and facilitating the production. This method has many variations and has been studied both theoretically and experimentally (in pilot projects and in full field applications). In order to increase oil recovery and reduce steam injection costs, the injection of alternative fluid has been used on three main ways: alternately, co-injected with steam and after steam injection interruption. The main objective of these injection systems is to reduce the amount of heat supplied to the reservoir, using cheaper fluids and maintaining the same oil production levels. This works discusses the use of carbon dioxide, nitrogen, methane and water as an alternative fluid to the steam. The analyzed parameters were oil recoveries and net cumulative oil productions. The reservoir simulation model corresponds to an oil reservoir of 100 m x 100 m x 28 m size, on a Cartesian coordinates system (x, y and z directions). It is a semi synthetic model with some reservoir data similar to those found in Brazilian Potiguar Basin. All studied cases were done using the simulator STARS from CMG (Computer Modelling Group, version 2009.10). It was found that waterflood after steam injection interruption achieved the highest net cumulative oil compared to other fluids injection. Moreover, it was observed that steam and alternative fluids, co-injected and alternately, did not present increase on profitability project compared with steamflooding

Saturação em CO2 e regulação metabólica do bacterioplancton em ecossistemas aquáticos de baixa latitude

Conselho Nacional de Desenvolvimento Científico e Tecnológico

Extração do óleo essencial de Cymbopogom winterianus J. com CO2 pressurizado

The extraction with pressurized fluids has become an attractive process for the extraction of essential oils, mainly due the specific characteristics of the fluids near the critical region. This work presents results of the extraction process of the essential oil of Cymbopogon winterianus J. with CO2 under high pressures. The effect of the following variables was evaluated: solvent flow rate (from 0.37 to 1.5 g CO2/min), pressure (66.7 and 75 bar) and temperature (8, 10, 15, 20 and 25 ºC) on the extraction kinetics and the total yield of the process, as well as in the solubility and composition of the C. winterianus essential oil. The experimental apparatus consisted of an extractor of fixed bed and the dynamic method was adopted for the calculation of the oil solubility. Extractions were also accomplished by conventional techniques (steam and organic solvent extraction). The determination and identification of extract composition were done by gas chromatography coupled with a mass spectrometer (GC-MS). The extract composition varied in function of the studied operational conditions and also related to the used extraction method. The main components obtained in the CO2 extraction were elemol, geraniol, citronellol and citronellal. For the steam extraction were the citronellal, citronellol and geraniol and for the organic solvent extraction were the azulene and the hexadecane. The most yield values (2.76%) and oil solubility (2.49x10-2 g oil/ g CO2) were obtained through the CO2 extraction in the operational conditions of T = 10°C, P = 66.7 bar and solvent flow rate 0.85 g CO2/min

Avaliação da remoção de sulfeto de hidrogênio do gás natural em uma coluna de absorção

Natural gas, although basically composed by light hydrocarbons, also presents in its composition gaseous contaminants such as CO2 (carbon dioxide) and H2S (hydrogen sulfide). Hydrogen sulfide, which commonly occurs in oil and gas exploration and production activities, besides being among the gases that are responsible by the acid rain and greenhouse effect, can also cause serious harm to health, leading even to death, and damages to oil and natural gas pipelines. Therefore, the removal of hydrogen sulfide will significantly reduce operational costs and will result in oil with best quality to be sent to refinery, thereby resulting in economical, environmental, and social benefits. These factors highlight the need for the development and improvement of hydrogen sulfide sequestrating agents to be used in the oil industry. Nowadays there are several procedures for hydrogen sulfide removal from natural gas used by the petroleum industry. However, they produce derivatives of amines that are harmful to the distillation towers, form insoluble precipitates that cause pipe clogging and produce wastes of high environmental impact. Therefore, the obtaining of a stable system, in inorganic or organic reaction media, that is able to remove hydrogen sulfide without forming by-products that affect the quality and costs of natural gas processing, transport and distribution is of great importance. In this context, the evaluation of the kinetics of H2S removal is a valuable procedure for the treatment of natural gas and disposal of the byproducts generated by the process. This evaluation was made in an absorption column packed with Raschig ring, where natural gas with H2S passes through a stagnant solution, being the contaminant absorbed by it. The content of H2S in natural gas in column output was monitored by an H2S analyzer. The comparison between the obtained curves and the study of the involved reactions have not only allowed to determine the efficiency and mass transfer controlling step of the involved processes but also make possible to effect a more detailed kinetic study and evaluate the commercial potential of each reagent