Avaliação e modelagem reológica de fluido de perfuração base água

The determination of the rheology of drilling fluids is of fundamental importance to select the best composition and the best treatment to be applied in these fluids. This work presents a study of the rheological behavior of some addictives used as viscosifiers in water-based drilling fluids. The evaluated addictives were: Carboxymethylcellulose (CMC), Xanthan gum (GX), and Bentonite. The main objective was to rheologically characterize suspensions composed by these addictives, by applying mathematical models for fluid flow behavior, in order to determine the best flow equation to represent the system, as well as the model parameters. The mathematical models applied in this research were: the Bingham Model, the Ostwald de Wale Model, and the Herschel-Bulkley Model. A previous study of hydration time for each used addictive was accomplished seeking to evaluate the effect of polymer and clay hydration on rheological behavior of the fluid. The rheological characterization was made through typical rheology experiments, using a coaxial cylinder viscosimeter, where the flow curves and the thixotropic magnitude of each fluid was obtained. For each used addictive the rheological behavior as a function of temperature was also evaluated as well as fluid stability as a function of the concentration and kind of addictive used. After analyses of results, mixtures of polymer and clay were made seeking to evaluate the rheological modifications provided by the polymer incorporation in the water + bentonite system. The obtained results showed that the Ostwald de Waale model provided the best fit for fluids prepared using CMC and for fluids with Xanthan gum and Bentonite the best fit was given by the Herschel-Bulkley one

Reaproveitamento e caracterização dos resíduos orgânicos provenientes do Programa MESA DA SOLIDARIEDADE da CEASA/RN

As an auxiliary tool to combat hunger by decreasing the waste of food and contributing for improvement of life quality on the population, CEASA/RN has released from August/03 to August/05 the program MESA DA SOLIDARIEDADE. Despite of the positive results of this program, that has already distributed around 226 tons of food, there is still food being thrown in the trash as the deliver of the same food in its natural form would be a health risk to those who would consume it and only the correct processing of this food can make it edible. This work has as a goal the reuse of solid residues of vegetal origin generated by the CEASA/RN, through the Program MESA DA SOLIDARIEDADE and the characterization of the product obtained so it might be used as a mineral complement in the human diet. To the collecting of samples (from September until December /2004) it was developed a methodology having as a reference the daily needs of mineral salts for infants at the age of seven to ten. The sample was packed in plastic bags and transported in an ambient temperature to the laboratory where it was selected, weighted, disinfected, fractionated and dried to 70ºC in greenhouse. The dry sample was shredded and stored in bottles previously sterilized. The sample in nature was weighted in the same proportion of the dry sample and it was obtained a uniform mass in a domestic processor. The physical-chemical analyses were carried out in triplicate in the samples in nature and in the dry product, being analyzed: pH, humidity, acidity and soluble solids according to IAL (1985), mineral salts contents (Ca, K, Na, Mg, P and Fe) determined by spectrophotometry of Atomic Absorption, caloric power through a calorimetric bomb and presence of fecal traces and E. coli through the colilert method (APHA, 1995). During this period the dry food a base of vegetables presented on average 5,06% of humidity, 4,62 of pH, acidity of 2,73 mg of citric acid /100g of sample, 51,45ºBrix of soluble solids, 2.323,50mg of K/100g, 299,06mg of Ca/100g, 293mg of Na/100g, 154,66mg of Mg/100g, 269,62mg of P/100g, 6,38mg of Fe/100g, caloric power of 3,691Kcal/g (15,502KJ/g) and is free of contamination by fecal traces and E..coli. The dry food developed in this research presented satisfactory characteristics regarding to its conservation, possessing low calories, constituting itself a good source of potassium, magnesium, sodium and iron that can be utilized as a food complement of these minerals

Avaliação preliminar da viabilidade de produção in vitro de um isolado brasileiro de baculovírus Spodoptera frugiperda MNPV

In vivo production of viral biopesticides is the major source of viral insecticides currently in the marketplace. However, this system presents limitations during production scale-up. For the Spodoptera frugiperda nucleopolyhedrovirus (SfMNPV), the insect used for replication has cannibalistic characteristics, thus production is even more difficult. Insect cells are commonly used for in vitro baculovirus production. Most of these cell lines are derived from Lepidoptera species. The Sf21 cell line is derived from Spodoptera frugiperda caterpillar ovarian tissue, and its clonal isolate Sf9 has been used for biopesticide production due to its ease of growth in suspension cultures. In this work, the in vitro production capabilities of a Brazilian SfMNPV isolate obtained from cornfields was evaluated. Comparison of polyhedra production was carried out using both Sf21 and Sf9 cells, based on volumetric and specific yields. Both cell lines were cultivated in Hyclone medium supplemented with different fetal bovine serum concentrations (2,5 and 5%). The best results were obtained using Sf9 cells supplemented with 5% serum. These results were further confirmed quantitively through kinetic parameter estimation for both cells lines and different serum concentrations. After seven successive passages, this system still presented high specific polyhedra production

Degradação fotoquímica de hidrocarbonetos da gasolina em efluentes aquosos

Photo-oxidation processes of toxic organic compounds have been widely studied. This work seeks the application of the photo-Fenton process for the degradation of hydrocarbons in water. The gasoline found in the refinery, without additives and alcohol, was used as the model pollutant. The effects of the concentration of the following substances have been properly evaluated: hydrogen peroxide (100-200 mM), iron ions (0.5-1 mM) and sodium chloride (200 2000 ppm). The experiments were accomplished in reactor with UV lamp and in a falling film solar reactor. The photo-oxidation process was monitored by measurements of the absorption spectra, total organic carbon (TOC) and chemical oxygen demand (COD). Experimental results demonstrated that the photo-Fenton process is feasible for the treatment of wastewaters containing aliphatic hydrocarbons, inclusive in the presence of salts. These conditions are similar to the water produced by the petroleum fields, generated in the extraction and production of petroleum. A neural network model of process correlated well the observed data for the photooxidation process of hydrocarbons

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

Tratamento de materiais contaminados com bifenilas policloradas (PCBS) via extração convencional e fluído supercrítico

The decontamination of the materials has been subject of some studies. One of the factors that it increases the pollution is the lack of responsibility in the discarding of toxic trash, as for example the presence of PCB (Polychlorinated Biphenyls) in the environment. In the Brazilian regulations, the material contaminated with PCB in concentrations higher than 50 ppm must be stored in special places or destroyed, usually by incineration in plasma furnace with dual steps. Due to high cost of the procedure, new methodologies of PCBs removal has been studied. The objective of this study was to develop an experimental methodology and analytical methodology for quantification of removal of PCBs through out the processes of extractions using supercritical fluid and Soxhlet method, also technical efficiency of the two processes of extraction, in the treatment of contaminated materials with PCBs. The materials studied were soils and wood, both were simulated contamination with concentration of 6.000, 33.000 and 60.000 mg of PCB/ kg of materials. Soxhlet extractions were performed using 100 ml of hexane, and temperature of 180 ºC. Extractions by fluid supercritical were performed at conditions of 200 bar, 70°C, and supercritical CO2 flow-rate of 3 g/min for 1-3 hours. The extracts obtained were quantified using Gas chromatography-mass spectrometry (GC/MS). The conventional extractions were made according to factorial experimental planning technique 22, with aim of study the influence of two variables of process extraction for the Soxhlet method: contaminant concentration and extraction time for obtain a maximum removal of PCB in the materials. The extractions for Soxhlet method were efficient for extraction of PCBs in soil and wood in both solvent studied (hexane and ethanol). In the experimental extraction in soils, the better efficient of removal of PCBs using ethanol as solvent was 81.3% than 95% for the extraction using hexane as solvent, for equal time of extraction. The results of the extraction with wood showed statistically it that there is not difference between the extractions in both solvent studied. The supercritical fluid extraction in the conditions studied showed better efficiency in the extraction of PCBs in the wood matrix than in soil, for two hours extractions the obtain percentual of 43.9 ± 0.5 % for the total of PCBs extracted in the soils against 95.1 ± 0,5% for the total of PCBs extracted in the wood. The results demonstrated that the extractions were satisfactory for both technical studied

Estudo da oxidação do metabissulfito de sódio contido no efluente da carcinicultura

The shrimp farming is a process of creation of shrimp that has been growing rapidly in the country, occupying a meaningful space in the Brazilian exporting. In 2003, this activity presented a volume of 60 millions of tons and 220 millions of dollars, being the main generator of employment and income of the primary sector of the northeast economy. However, it is a new activity with c.a. five years in the Rio Grande do Norte State and therefore needs investment in the technological area. Among the wastewaters of this activity, the sulphite solution is being usually applied in the process of fishing, i.e. retrieval of the shrimps from the farming. The aim of this work is to present the oxidation experimental results of the sulphite that may be and to determine what it s the most efficient method, trough laboratory experiments. The measurements were carried out in a mixing reactor inserting air and with hydrogen peroxide addition with and without UV light. The solutions were prepared synthetically with concentrations found in the wastewater of fishing and also collected in locu. The oxidation process using air was monitorated by iodometric analysis for the sulphite and the oxidation using hydrogen peroxide was evaluated with turbidimetric analysis for sulphate, by spectrophotometer. The sulphite was totally oxidized in both processes. The experimental results permit to conclude that the oxidation by hydrogen peroxide is more efficient and allowed to determine the optimum operational conditions in terms of concentration and time of treatment

Produção de quitosanase por aspergillus ochraceus em cultivo descontínuo submerso

In this work a 24 factorial design with triplicate at central point was used in order to investigate the influence of chitosan concentration (substrate) (Cs), culture media temperature (CMT), aeration ratio (AR) as well as agitation (A) on chitosanase production by Aspergillus ochraceus. Experiments were carried out using the following levels to the factors: (Cs) (-1) 0.1%; (0) 0.15%; (+1) 0.2%; (TMC) (-1) 25 minutes; (0) 30 minutes; (+1) 35 minutes; (RA) (-1) 0.4; (0) 0.6; (+1) 0.8; (A) (-1) 90 rpm, (0) 120 rpm, (+1) 150 rpm. One chitosanolytic activity (U.mL-1) was defined as the enzyme necessary to produce 1.0 mmol.min-1 of glicosamine by mL of extract. Chitosanolytic assays were carried out using two extract volumes, 0.05 and 0.1 mL, respectively. Results showed that was possible to produce chitosanase of order aproximatelly 5,9 U.mL-1 by Aspergillus ochraceus and chitosanolytic activity was increased by increment on substrate concentration, aeration ratio as well as agitation while media culture temperature increment decreased activity

Propriedades cerâmicas e imobilização do manganês em cerâmica estrutural

In this work is the addition of a metallic ion, of the metal Manganese, in a clay of Rio Grande do Norte state for structural ceramics use, the objective this study was to assess the evolution of ceramic properties. The clay was characterized by Chemical and Thermal analysis and Xray difraction. The metallic ion was added in the clay as aqueous solutions at concentrations of 100, 150 and 200 mg / L. The molded by extrusion and the burned were temperatures at 850, 950, 1050 and 1150 º C. Was made Chemical Analysis and investigated the following parameters environmental and ceramic: Solubility, Colour, Linear Retraction (%), Water Absorption (%), Gresification Curves, Apparent Porosity (%), Apparent Specific Mass (g/cm3) and Flexion Rupture Module (kgf/cm2). The results showed that increasing the concentration of metallic ion, properties such as Apparent Porosity (%), Water Absorption (%) decreases and the Flexion Rupture Module (kgf/cm2) increases with increasing temperature independent of the concentration of the ion. The gresification curves showed that the optimum firing temperatures were in the range between 950 and 1050 ° C. The evaluation of the properties showed that the ceramic material can be studied its use in solid brick and ceramic materials with structural function of filling. The results of solubility showed that the addition of ion offers no risk to the environment

Estudo das propriedades físico-químicas de biocombustíveis microemulsionados

The development of new fuels is an important field of scientific and technological activities, since much of the energy consumed in the world is obtained from oil, coal and natural gas, and these sources are limited and not renewable. Recently it has assessed the employment of microemulsions as an alternative for obtaining fuel isotropic between phases originally not miscible. Among many advantages, emphasizes the application of substances that provide the reduction of levels of emissions compared to fossil fuels. Thus, this work was a study of various microemulsified systems, aiming to check the performance of the winsor regions front of the use of surfactants: RENEX 18 → 150, UNITOL L-60 → L-100 and AMIDA 60, together with structure of esters from soybean and castor bean oils. From the results it were chosen four systems to physico-chemical analyzes: System I RENEX 60, Soil bean oil, methylic ester (EMOS) and water; System II RENEX 60/AMIDA 60, EMOS and water; System III RENEX 70, mamona oil methylic ester (EMOM) and water and System IV RENEX 95, EMOM and water. The tests of physico-chemical characterization and study of temperature increase were done with nine points with different compositions in a way to include the interest area (microemulsion W/O). After this study, was conducted a modeling to predict the viscosity, the property is more varied as function of compositions systems changes. The best results were the systems II and IV with a temperature stability above 60°C. The system I had its physico-chemical characterization very similar to a fossil fuel. The system II was the best one due to its corrosivity be stable. In the modeling the four systems had shown good, with an error that varied between 5 and 18%, showing to be possible the viscosity prediction from the composition of the system. The effects the microemulsion and the engine´s performance with the microemulsion were also avaliated. The tests were performed in a cycle-diesel engine. The potency and consumption were analysed. Results show a slight increase the rendiment fuel compared with the conventional as well as a decrease in specific consumption

Aproveitamento de subprodutos da industrialização do escargot

The waste in the industries of escargot processing is very big. This is composed basically of escargot meat out of the commercialization patterns and the visceras. In this context, there is a need to take advantage to the use of these sub-products. A possibility should be drying them and transforming them in a certain form to be reused. Than, the present work has the objective of studying the reutilization of the sub-products of the escargot industrialization for by means of drying process. The samples were transformed in pastes, through a domestic processor for approximately 1 minute and compacted in trays of aluminum without perforations with three different heights (5 mm, 10 mm and 15 mm). The drying was accomplished in a tray dryer with air circulation and transverse flow at a speed of 0,2 m/s and three temperature levels (70°C, 80°C and 90ºC). A drying kinetics study was accomplished for the obtained curves and for the heat and mass transfer coefficients using experimental procedures based in an experimental planning of 22 factorial type. Microbiological and physiochemical analysis were also accomplished for the in nature and the dehydrated sub-products. In the drying process, it was observed the great importance of the external resistances to the mass transfer and heat in the period of constant tax influenced by the temperature. The evaporation taxes indicated a mixed control of the mass transfer for the case of the thickest layers. As already expected, the drying constant behavior was influenced by the temperature and thickness of the medium, increasing and decreasing. The statistical analysis of the results, in agreement with the factorial planning 22, showed that the fissures, the shrinking of the transfer area and the formation of a crust on the surface might have contributed to the differences between the practical results and the linear model proposed. The temperature and the thickness influenced significantly in the answers of the studied variables: evaporation tax and drying constant. They were obtained significant statistical models and predictive ones for evaporation tax for the meat as well as for the visceras

Estudo da hidrodinâmica de um novo separador líquido-líquido: aplicação ao sistema óleo-bruto/água produzida

This work aims to use a different hydrodynamic condition applied to a new design of mixer-settler on treating wastewater produced by petroleum industry, called MDIF (Misturador-Decantador à Inversão de Fases/ Mixer-Settler based on Phase Inversion MSPI). The use of this different hydrodynamic behaviour is possible due to vertical disposition of the device and the principle of Phase Inversion that controls the MDIF, providing the generation (creation) of a cascade of drops, into an organic layer, that works as micro-decanters, thus making possible the formation of a bed of non-coalesced drops, called Bed Formation . The use of this new hydrodynamics condition allows to increase the residence time of the oil carrier drops, into an organic layer, and the device can treat a greater volume of wastewater. In view of to get this condition it is necessary to operate at high throughput (58,6 m3.m-2.h-1). By results, the condition of Bed Formation is the best one to be used when MSPI operates with throughput up to 58,6 m3.m-2.h-1. The results using the condition of Bed Formation show that increasing the height of the bed of non-coalesced drops and/or decreasing the volumetric ratio (O/A) an increase of the separation efficiency is detected

Avaliação da temperatura de cristalização da parafina em sistemas: parafina, solvente e tensoativo

The formation of paraffin deposits is common in the petroleum industry during production, transport and treatment stages. It happens due to modifications in the thermodynamic variables that alter the solubility of alkanes fractions present in petroleum. The deposition of paraffin can provoke significant and growing petroleum losses, arriving to block the flow, hindering to the production. This process is associated with the phases equilibrium L-S and the stages and nucleation, growth and agglomeration the crystals. That process is function of petroleum intrinsic characteristics and temperature and pressure variations, during production. Several preventive and corrective methods are used to control the paraffin crystallization, such as: use of chemical inhibitors, hot solvents injection, use of termochemistry reactions, and mechanical removal. But for offshore exploration this expensive problem needs more investigation. Many studies have been carried through Wax Appearance Temperature (WAT) of paraffin; therefore the formed crystals are responsible for the modification of the reologics properties of the oil, causing a lot off operational problems. From the determination of the WAT of a system it is possible to affirm if oil presents or not trend to the formation of organic deposits, making possible to foresee and to prevent problems of wax crystallization. The solvent n-paraffin has been widely used as fluid of perforation, raising the production costs when it is used in the removal paraffin deposits, needing an operational substitute. This study aims to determine the WAT of paraffin and the interference off additives in its reduction, being developed system paraffin/solvent/surfactant that propitiates the wax solubilization. Crystallization temperatures in varied paraffin concentrations and different solvents were established in the first stage of the experiments. In the second stage, using the methodology of variation of the photoelectric signal had been determined the temperature of crystallization of the systems and evaluated the interferences of additives to reduction of the WAT. The experimental results are expressed in function of the variations of the photoelectric signals during controlled cooling, innovating and validating this new methodology to determine WAT, relatively simple with relation the other applied that involve specific equipments and of high cost. Through the curves you differentiate of the results had been also identified to the critical stages of growth and agglomeration of the crystals that represent to the saturation of the system, indicating difficulties of flow due to the increase of the density

Purificação da glicerina bruta obtida a partir da transesterificação do óleo de algodão

The crude glycerine is a raw material that can be used in a wide variety of products. Even with all the impurities inherent in the process of being obtained, the crude glycerin is already in a marketable product. However, the market is much more favorable to the commercialization of purified glycerine. The glycerin is a byproduct gotten from the process of transesterification of waste oils and fats in the production of biodiesel. More recently, the deployment of the new Federal Law of Brazil, related to the implementation of energy resources, forces, from 2008, the increase of 2% biodiesel in diesel common with prospects for 5% (B5). Therefore, it is indispensable that new routes of purification as well as new markets are developed. The objective of this work was to purify, through ion exchange, the crude glycerin, obtained from the reaction of transesterification of cottonseed oil. The cottonseed oil was characterized as the fatty acid composition and physical-chemical properties. The process of ion exchange was conducted in batch. In this process were used strong cation, low anion resins and a mixed resin used to de-ionize water. The purified glycerin was characterized as the content of metals. Tests were performed with activated charcoal adsorption, and for this, it was made tests of time contact with coal as well as quantity of coal used. The time of activation, the amount of the activation solution, the contact time of the glycerol solution in resins, the amount and type of resin applied were evaluated. Considering the analysis made with activated charcoal, when the glycerin solution was treated using the resins individually it was observed that in the conditions for treatment with 10 g of resin, 5 hours of contact with each resin and 50 mL of glycerin solution, its conductivity decreased to a cationic resin, increased to the anionic resin and had a variable value with respect to resin mixed. In the treatment in series, there was a constant decrease in the conductivity of the solution of glycerin. Considering two types of treatment, in series and individually, the content of glycerol in glycerin pre-purified solution with the different resins varied from 12,46 to 29.51% (diluted solution). In analysis performed without the use of activated charcoal, the behavior of the conductivity of the solution of glycerin were similar to results for treatment with activated charcoal, both in series as individually. The solution of glycerin pre-purified had a glycerol content varying from 8.3 to 25.7% (diluted solution). In relation to pH, it had a behavior in accordance with the expected: acid for the glycerin solution treated with cationic resin, basic when the glycerin solution was treated with the anionic resin and neutral when treated with the mixed resin, independent of the kind of procedure used (with or without coal, resins individually or in series). In relation to the color of the glycerin pre-purified solution, the resin that showed the best result was the anionic (colorless), however this does not mean that the solution is more in pure glycerol. The chromatographic analysis of the solutions obtained after the passage through the resins indicated that the treatment was effective by the presence of only one component (glycerol), not considering the solvent of the analysis

Aplicação de microemulsões na solubilização de frações pesadas de petróleo

This work presents studies related to the use of microemulsions in the solubilization of heavy crude oil fractions responsible by the formation of deposits. The first stage of the work was addressed to the construction of phases diagrams, with the intention of determining the area within which the microemulsion is formed. The following systems were studied: UNITOL L 90 n-Butanol - Water - Kerosene (system 1); UNITOL L 90 - n-Butanol - Water - Xylene (system 2); UNITOL L 90 n-Butanol - Water - Kerosene/Xylene 10% (system 3); UNITOL L 90 - Sec-Butanol - Water - Xylene (system 4). In parallel experiments of physical adsorption were carried out by the static method, with the intention of simulating natural conditions of reservoirs. Crude oil of the Fazenda Belém field (Rio Grande do Norte), was used as solute, xylene as solvent and the Assu sandstone (Rio Grande do Norte, Brazil) and Botucatu sandstone (Paraná, Brazil) as rock reservoirs. The curves of adsorption presented the S format type, in agreement with the classification proposed by Giles, Smith and Huitson (1974). The solubilization process was accomplished in the batch method, by varying the time of agitation, the microemulsions and the solid/solution ratio. The experiments showed that the microemulsions presented high efficiency in the solubilization of the crude oil adsorbed on the sandstones. System 2 presented an efficiency of 99% for the Assu sandstone and 97% for the Botucatu sandstone