Estudo da influência da temperatura na degradação termoquímica da biomassa de avelós

The bio-oil obtained from the pyrolysis of biomass has appeared as inter-esting alternative to replace fossil fuels. The aim of this work is to evaluate the influence of temperature on the yield of products originating from the pyrolysis process of the powder obtained from the dried twigs of avelós (Euphorbia tirucalli), using a rotating cylinder reactor in laboratory scale. The biomass was treated and characterized by: CHNS, moisture, volatiles, fixed carbon and ashes, as well as evaluation of lignin, cellulose and hemicellulose, besides other instrumental techniques such as: FTIR, TG/DTG, DRX, FRX and MEV. The activation energy was evaluated in non-isothemichal mode with heating rates of 5 and 10 oC/min. The obtained results showed biomass as feedstock with potential for biofuel production, because presents a high organic matter content (78,3%) and fixed-carbon (7,11%). The activation energy required for the degradation of biomass ranged between 232,92 392,84 kJ/mol, in the temperature range studied and heating rate of 5 and 10°C/min. In the pyrolysis process, the influence of the reaction temperature was studied (350-520 ° C), keeping constant the other variables, such as, the flow rate of carrier gas, the centrifugal speed for the bio-oil condensationa, the biomass flow and the rotation of the reactor. The maximum yield of bio-oil was obtained in the temperature of 450°C. In this temperature, the results achieved where: content of bio-oil 8,12%; char 32,7%; non-condensed gas 35,4%; losts 23,8%; gross calorific value 3,43MJ/kg; pH 4,93 and viscosity 1,5cP. The chromatographic analysis of the bio-oil produced under these conditions shows mainly the presence of phenol (17,71%), methylciclopentenone (10,56%) and dimethylciclopentenone (7,76%)

Estudo da influência da temperatura na degradação termoquímica da biomassa de avelós (euphorbia tirucalli Linn)

The bio-oil obtained from the pyrolysis of biomass has appeared as inter-esting alternative to replace fossil fuels. The aim of this work is to evaluate the influence of temperature on the yield of products originating from the pyrolysis process of the powder obtained from the dried twigs of avelós (Euphorbia tirucalli), using a rotating cylinder reactor in laboratory scale. The biomass was treated and characterized by: CHNS, moisture, volatiles, fixed carbon and ashes, as well as evaluation of lignin, cellulose and hemicellulose, besides other instrumental techniques such as: FTIR, TG/DTG, DRX, FRX and MEV. The activation energy was evaluated in non-isothemichal mode with heating rates of 5 and 10 oC/min. The obtained results showed biomass as feedstock with potential for biofuel production, because presents a high organic matter content (78,3%) and fixed-carbon (7,11%). The activation energy required for the degradation of biomass ranged between 232,92 392,84 kJ/mol, in the temperature range studied and heating rate of 5 and 10°C/min. In the pyrolysis process, the influence of the reaction temperature was studied (350-520 ° C), keeping constant the other variables, such as, the flow rate of carrier gas, the centrifugal speed for the bio-oil condensationa, the biomass flow and the rotation of the reactor. The maximum yield of bio-oil was obtained in the temperature of 450°C. In this temperature, the results achieved where: content of bio-oil 8,12%; char 32,7%; non-condensed gas 35,4%; losts 23,8%; gross calorific value 3,43MJ/kg; pH 4,93 and viscosity 1,5cP. The chromatographic analysis of the bio-oil produced under these conditions shows mainly the presence of phenol (17,71%), methylciclopentenone (10,56%) and dimethylciclopentenone (7,76%)

Avaliação termoanalítica da eficiência de antioxidantes na estabilidade oxidativa do biodiesel de mamona

The biodiesel is defined as the mono-alkyl ester derived from long-chain fatty acids, from renewable sources such as vegetable oils or animal fat, whose use is associated with the replacement of fossil fuels in diesel engine cycle. The biodiesel is susceptible to oxidation when exposed to air and this process of oxidation affects the quality of fuel, mainly due to long periods of storage. Because of this, the oxidation stability has been the focus of numerous researches since it directly affects the producers, distributors and users of fuel. One of the possibilities to increase the resistance of biodiesel is the autoxidation treatment with inhibitors of oxidation. The antioxidants can be used as potential inhibitors of the effects of oxidation on the kinematic viscosity and the index of acidity of biodiesel, thereby increasing oxidative stability. This work aims to examine the efficiency of antioxidants, α-tocopherol and butylated hydroxy-toluene (BHT), added the biodiesel content of remembrance through Pressurized-Differential Scanning Calorimetry (P-DSC), Thermogravimetry (TG) and Petrology. The results showed that the use of antioxidant BHT, at the concentration of 2000ppm, increased resistance to oxidation of the biodiesel and oxidative induction time (OIT), which is a better result as antioxidant than the α-tocopherol. With the thermogravimetric analysis, it was observed that the biodiesel presented an initial decomposition temperature of lower tendency than that of oil, demonstrating to be more volatile, bearing great similarity to the diesel and being characterized as an alternative fuel. The rheological analysis indicated that each sample of biodiesel behaved as a Newtonian fluid

Avaliação da remoção de hidrocarbonetos aromáticos (BTEX) em águas utilizando materiais nanoestruturados do tipo Ti-MCM-41

Volatile Organic Compounds are pollutants coming mainly from activities that use fossil fuels. Within this class are the BTEX (benzene, toluene, ethylbenzene and xylenes) compounds that are considered hazardous. Among the various existing techniques for degradation of pollutants, there is advanced oxidation using H2O2 generating hidoxil radical ( OH). In this work, the mesoporous material of MCM-41 was synthesized by hydrothermal method and then was used as support, the impregnation of titanium by the method of synthesis with excess solvent to obtain the catalyst Ti-MCM-41. The catalyst was used in the reaction catalyzed removal of BTEX in water using H2O2 as oxidant. The materials were characterized by: XRD, TG/DTG, FTIR, nitrogen adsorption-desorption and FRX-EDX, in order to verify the method of impregnation of the mesoporous titanium support was effective. Catalytic tests were carried out in reactors of 20 mL containing BTEX (100.0 μg/L), H2O2 (2.0 M) and Ti-MCM-41 (2.0 g/L) in acid medium. The reaction occurred for 5 h at 60 °C and analysis were performed by gas chromatography with photoionization detector and static headspace sampler. The characterizations have proven the effectiveness of the synthesis method used and the incorporation of titanium lt in the support. The catalytic tests showed satisfactory results with conversion of more than 95 % for the studied compounds, where the catalyst 48% Ti-MCM-41 showed a higher removal efficiency of the compounds under study

Eficiência do processo de obtenção do biodiesel de girassol usando o catalisador KNO3/Al2O3

It is known that the head office world energetics is leaning in the fossil fuels. However, the world panorama is changing quickly, for linked reasons to three of the humanity's great concerns in that century beginning: environment, global economy and energy. The biodiesel production is based on the transesterificação of vegetable oils or animal fats, using catalysts homogeneous or heterogeneous. The process of heterogeneous transesterificação presents lower conversions in comparison with the homogeneous, however, it doesn't present corrosion problems and it reduces to the occurrence of parallel reactions as saponification. In this sense, this work has for purpose the synthesis of a heterogeneous catalyst, KNO3/Al2O3, that soon afterwards was used in the reaction of transesterificação of the oil of the Helianthus annuus L. (sunflower). The solid materials (it supports and catalyst) they were analyzed by diffraction of ray-X (XRD) and electronic microscope of sweeping (MEV). After the analysis of Al2O3, a structure monophase amorphous tetragonal was verified, with characteristic patterns of that material, what could not be visualized in the difratograma of the catalyst. The biodiesel obtained with 4% wt. of KNO3/Al2O3 it was what obtained a better cinematic viscosity 8,3 mm2/s, comparing with the norms of ANP, and it also presented the best conversion tax in ethyl ésteres, in accordance with the quantitative measure starting from TG, that was of 60%. While the biodiesel with 6% wt. and with 8% wt. of KNO3/Al2O3 it was it that no transesterificou, because it was observed in the analysis termogravimétrica of those two materials, a single thermal event, that it corresponds the decomposition or volatilization of the triglycerides

Estudo do óleo das sementes de Carthamus tinctorius L. Para produção de biodiesel

Most of the energy consumed worldwide comes from oil, coal and natural gas. These sources are limited and estimated to be exhausted in the future, therefore, the search for alternative sources of energy is paramount. Currently, there is considerable interest in making trade sustainable biodiesel, a fuel alternative to fossil fuels, due to its renewable nature and environmental benefits of its use in large scale. This trend has led the Brazilian government to establish a program (Probiodiesel) with the aim of introducing biodiesel into the national energy matrix, by addition of 5% biodiesel to conventional diesel in 2010 to foster not only the increase of renewable energy, but reduce imports of crude oil. This work evaluates different methods of extraction of oil Carthamus tinctorius L., their characterization by IR, 1H and 13C NMR, HPLC and TG and their use in the production of methyl ester (molar ratio of oil / alcohol 1:6, and NaOH catalyst). The physico-chemical parameters (acid value, density, viscosity, saponification index and surface tension) of oil and biodiesel were also described. The produced biodiesel had a yield of 93.65%, was characterized in relation to their physicochemical properties showing satisfactory results (density=875 kg/m3, viscosity = 6.22 mm2/s, AI = 0.01 mg (NaOH) /g) compared with the values established by the the National Agency Oil, Natural Gas and Biofuels

Síntese e caracterização de óxidos de zinco e de magnésio suportados em A1SBA-15 para produção de biodiesel

To overcome the challenge of meeting growing energy demand in a sustainable way, biodiesel has shown very promising as alternative energy can replace fossil fuels, even partially. Industrially, the biodiesel is produced by homogeneous transesterification reaction of vegetable oils in the presence of basic species used as catalysts. However, this process is the need for purification of the esters obtained and the removal of glycerin formed after the reaction. This context, the alternative catalysts have that can improve the process of biodiesel production, aiming to reduce costs and facilitate its production. In this study, the AlSBA-15 support with Si / Al ratio = 50 was synthesized, as like as the heterogeneous catalysts of zinc oxide and magnesium supported on mesoporous AlSBA-15 silica, in the concentrations of 5, 10, 15 and 30 %, relative to the support. The textural properties and structural characterization of catalysts and supports were determined by techniques: X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) coupled to the chemical analyzer, adsorption / desorption of N2, thermal analysis (TG / DTG), absorption spectroscopy in the infrared (FTIR) and X-ray photoelectron spectroscopy (XPS). Characterization results indicated that the support AlSBA-15 retained the hexagonal ordered after the incorporation of zinc oxide and magnesium oxide in the holder. For heterogeneous catalysts, ZnO-AlSBA-15, that was observed the presence of zinc oxide nanoparticles dispersed in the surface and interior channels of the mesoporous and microporous support. The catalytic activity was evaluated by the transesterification reaction of sunflower oil via methylic route, and some reaction parameters were optimized with the most active catalyst in biodiesel production by sunflower oil. For the series of heterogeneous catalysts, the sample with 30 % ZnO supported on AlSBA-15 showed a better conversion of triglyceride to methyl esters, about 95.41 % of reaction conditions: temperature 175 °C, with molar ratio of 42:1, stirring at 200 rpm and under a pressure of 14 bar for 6 h. The catalyst MgO-AlSBA-15 showed no catalytic activity in the studied reactions

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

Usos potenciais de moringa oleifera lam., uma matriz para produção de biodiesel e tratamento de água no semiárido nordestino

The current environmental crisis demands transformations in the relations among society, nature and development, considering sustainability. In this context, an important theme is replacing fossil fuels with biofuels, such as biodiesel. Moringa oleifera Lam. is a species that can be used as a raw material to produce biodiesel. Besides, it is a multiple purposes plant, which can be used also in water treatment. Thus, the aims of this work were to analyze the anatomical adaptations found in the stem and in the leaf and the seed s oil stores of M. oleifera., to investigate chemical characteristics of M. oleifera s seed oil, considering biodiesel production, and to evaluate the coagulation activity of these seeds in water treatment. Semipermanent histological laminas were made and it follows that the stem has thick cuticle, stomata whose cells guard are below the epidermis line, hollow medulla, druses and tector trichomes as adaptations to climate and soil conditions in which the species is found and the leaf is dorsiventral and it has thick cuticle, tector trichomes and druses. The seed has great reserves of oil. These features favor the use of Moringa oleifera Lam. as a raw material to produce biodiesel in Brazil s Northeast semiarid region. Chemical analysis were made through oil solvent extraction using mechanic stirrer. The oil was analyzed in UV spectrophotometer. A transesterification was made and biodiesel was analyzed in gas chromatography. Oil yield was high and good quality biodiesel was obtained. To evaluate seeds coagulantion activity, coagulation and flocculation essays in jartest were made, using seed extract to treat raw water. Seeds were efficient in cogulation process to treat water. So, they can be used in rudimentary systems or as a raw material to coagulant proteins extraction, as an alternative to traditional coagulants. M. oleifera has characteristics that favor its use to biodiesel production and water treatment

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

Monitoramento da qualidade das ásguas de chuvas conforme a atuação dos sistemas sinóticos na cidade de Natal/RN

Acid rain is a major assault on the environment, a consequence of burning fossil fuels and industrial pollutants the basis of sulfur dioxide released into the atmosphere. The objective of this research was to monitor and analyze changes in water quality of rain in the city of Natal, seeking to investigate the influence of quality on a local, regional and global, in addition to possible effects of this quality in the local landscape. Data collection was performed from December 2005 to December 2007. We used techniques of nefanálise in identifying systems sinóticos, field research in the search for possible effects of acid rain on the landscape, and collect and analyze data of precipitation and its degree of acidity. Used descriptive statistics (standard deviation and coefficient of variation) used to monitor the behavior of chemical precipitation, and monitoring of errors in measurements of pH, level of confidence, Normalized distribution of Gauss, confidence intervals, analysis of variance ANOVA were also used. Main results presented as a variation of pH between 5,021 and 6,836, with an average standard deviation of 5,958 and 0,402, showing that the average may represent the sample. Thus, we can infer that, according to the CONAMA Resolution 357 (the index for fresh water acidity should be between 6.0 and 9.0), the precipitation of Natal / RN is slightly acidic. It appears that the intertropical convergence zone figures showed the most acidic among the systems analyzed sinóticos, taking its average value of pH of 5,617, which means an acid value now, with a standard deviation of 0,235 and the coefficient of variation of 4,183% which shows that the average may represent the sample. Already in field research and found several places that suffer strongly the action of acid rain. However, the results are original and need further investigation, including the use of new methodologies

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.

Desempenho de um motor de trator agrícola em bancada dinamométrica com biodiesel de óleo de frango e misturas binárias com óleo diesel

O Brasil, terceiro maior produtor de biodiesel do mundo e terceiro maior produtor mundial de frango, pode incrementar, na sua matriz energética, o uso de óleo oriundo de aves como alternativa aos combustíveis fósseis e à redução da dependência do óleo de soja para esse fim. O país dispõe de mais de 350 milhões de litros de óleo de frango por ano. Considerando a aplicação dos combustíveis alternativos para os motores a diesel, em máquinas agrícolas, o trabalho teve por objetivo avaliar o desempenho do motor de um trator agrícola de 53kW acoplado pela TDP em bancada dinamométrica, operando com biodiesel metílico de óleo de frango e misturas com óleo diesel, sendo: B5 (testemunha), B20, B40, B60, B80 e B100. Avaliaram-se a potência, o torque, a reserva de torque, o consumo de combustível, o consumo de energia e a eficiência térmica do motor. O ensaio foi instalado com delineamento inteiramente casualizado (DIC) em esquema fatorial com seis tratamentos. Os resultados foram submetidos à análise de variância e as médias ajustadas por equações de regressão. Foram observadas perdas na geração de potência e torque, aumento no consumo de combustível, redução do consumo energético e melhoria na eficiência térmica do motor, de acordo com o aumento da proporção de biodiesel na mistura.

Toxic effects of nickel exposure on heart and liver of rats

The role of air pollution as a health risk factor is of special interest. Numerous toxic pollutants, such as nickel, are being released to the environment as a result of combustion of fossil fuels, crude oil, and coal. Nickel in the atmosphere can be combined with other environmental pollutants, producing various nickel compounds, which have varying animal toxicity. A rat biossay validated for the identification of toxic effects of nickel revealed increased serum activities of total lactate dehydrogenase (LDH) and alanine transaminase (ALT) in rats that received intratracheal injection of Ni2+ in .09% saline solution of NiCl2. The total LDH activity was also increased in the heart, and the isoenzyme pattern showed the LDH1/LDH2 ratio elevated to greater than 1. We conclude that intratracheal administration of nickel induced cardiac and hepatic damage. The development of cardiac and hepatic damage and of increased enzymes' activities was only demonstrated when nickel had accumulated in these tissues, indicating that nickel depot is essential to its toxicity. Intratracheal administration of NiCl2 induced changes in LDH and ALT activities.

Summit of the Americas 1994-2009: selected indicators

Includes bibliography