Simulação computacional do escoamento em bombas de cavidades progressivas

The use of Progressing Cavity Pumps (PCPs) in artificial lift applications in low deep wells is becoming more common in the oil industry, mainly, due to its ability to pump heavy oils, produce oil with large concentrations of sand, besides present high efficiency when compared to other artificial lift methods. Although this system has been widely used as an oil lift method, few investigations about its hydrodynamic behavior are presented, either experimental or numeric. Therefore, in order to increase the knowledge about the BCP operational behavior, this work presents a novel computational model for the 3-D transient flow in progressing cavity pumps, which includes the relative motion between rotor and stator, using an element based finite volume method. The model developed is able to accurately predict the volumetric efficiency and viscous looses as well as to provide detailed information of pressure and velocity fields inside the pump. In order to predict PCP performance for low viscosity fluids, advanced turbulence models were used to treat, accurately, the turbulent effects on the flow, which allowed for obtaining results consistent with experimental values encountered in literature. In addition to the 3D computational model, a simplified model was developed, based on mass balance within cavities and on simplification on the momentum equations for fully developed flow along the seal region between cavities. This simplified model, based on previous approaches encountered in literature, has the ability to predict flow rate for a given differential pressure, presenting exactness and low CPU requirements, becoming an engineering tool for quick calculations and providing adequate results, almost real-time time. The results presented in this work consider a rigid stator PCP and the models developed were validated against experimental results from open literature. The results for the 3-D model showed to be sensitive to the mesh size, such that a numerical mesh refinement study is also presented. Regarding to the simplified model, some improvements were introduced in the calculation of the friction factor, allowing the application fo the model for low viscosity fluids, which was unsuccessful in models using similar approaches, presented in previous works

Estudo numérico de escoamento turbulento em padrão anular gás-líquido em dutos verticais

Multiphase flows in ducts can adopt several morphologies depending on the mass fluxes and the fluids properties. Annular flow is one of the most frequently encountered flow patterns in industrial applications. For gas liquid systems, it consists of a liquid film flowing adjacent to the wall and a gas core flowing in the center of the duct. This work presents a numerical study of this flow pattern in gas liquid systems in vertical ducts. For this, a solution algorithm was developed and implemented in FORTRAN 90 to numerically solve the governing transport equations. The mass and momentum conservation equations are solved simultaneously from the wall to the center of the duct, using the Finite Volumes Technique. Momentum conservation in the gas liquid interface is enforced using an equivalent effective viscosity, which also allows for the solution of both velocity fields in a single system of equations. In this way, the velocity distributions across the gas core and the liquid film are obtained iteratively, together with the global pressure gradient and the liquid film thickness. Convergence criteria are based upon satisfaction of mass balance within the liquid film and the gas core. For system closure, two different approaches are presented for the calculation of the radial turbulent viscosity distribution within the liquid film and the gas core. The first one combines a k- Ɛ one-equation model and a low Reynolds k-Ɛ model. The second one uses a low Reynolds k- Ɛ model to compute the eddy viscosity profile from the center of the duct right to the wall. Appropriate interfacial values for k e Ɛ are proposed, based on concepts and ideas previously used, with success, in stratified gas liquid flow. The proposed approaches are compared with an algebraic model found in the literature, specifically devised for annular gas liquid flow, using available experimental results. This also serves as a validation of the solution algorithm

Desenvolvimento e caracterização de soluções ternárias água-glicerol-propilenoglicol como fluido refrigerante secundário

Conselho Nacional de Desenvolvimento Científico e Tecnológico

Utilização do éster de soja como biolubrificante

The lubricants found in the market are of mineral or synthetic origin and harm to humans and the environment, mainly due to their improper discard. Therefore industries are seeking to develop products that cause less environmental impact, so to decrease mainly, operator aggression the Cutting Fluids became an emulsion of oil / water or water / oil. However, the emulsion was not considered the most suitable solution for environmental question, therefore the search for biodegradable lubricants and which no are toxic continues and so vegetable oils are seen, again, as a basis for the production of lubricants. The biggest problem with these oils is their oxidative instability that is intensified when working at high temperatures. The process transesterification decreases the oxidation, however changes some physical and chemical properties. Therefore soybean oil after the transesterification process was subjected to tests of density, dynamic viscosity, kinematic viscosity which is calculated from two parameters mentioned, flash point and acidity. Besides the physico-chemical test the soybean oil was subjected to a dynamic test in a tribometer adapted from a table vise, whose induced wear was the adhesive and ultimately was used as cutting fluid in a process of turning in two different materials, steel 1045 and cast iron. This latter test presented results below the mineral cutting fluid which it was compared in all tests, already in other experiments the result was satisfactory and other experiments not, so that chemical additives can be added to the oil analyzed to try equate all parameters and so formulate a biolubrificante not toxic to apply in machining processes of metalworking industry

Estudo das propriedades físico-químicas do biodiesel e suas influências na deterioração dos elastômeros aplicados no sistema de injeção dos motores diesel

The biodiesel use has become important due to its renewable character and to reduce environmental impacts during the fuel burning. Theses benefit will be valid if the fuel shows good performance, chemistry stability and compatibility with engines. Biodiesel is a good fuel to diesel engines due to its lubricity. Then, the aimed of this study was to verify the physicalchemistry properties of biodiesel and their correlations with possible elastomers damage after biodiesel be used as fuel in an injection system. The methodology was divided in three steps: biodiesels synthesis by transesterification of three vegetable oil (soybean, palm and sunflower) and their physical-chemistry characterization (viscosity, oxidative stability, flash point, acidity, humidity and density); pressurized test of compatibility between elastomers (NBR and VITON) and biodiesel, and the last one, analyze of biodiesels lubricity by tribological test ball-plan( HFRR). Also, the effect of mixture of biodiesel and diesel in different concentrations was evaluated. The results showed that VITON showed better compatibility with all biodiesel blends in relation to NBR, however when VITON had contact with sunflower biodiesel and its blends the swelling degree suffer higher influences due to biodiesel humidity. For others biodiesels and theirs blends, this elastomer kept its mechanical properties constant. The better tribological performance was observed for blends with high biodiesel concentration, lower friction coefficient was obtained when palm biodiesel was used. The main mechanisms observed during the HFRR tests were abrasive and oxidative wear

Caracterização do óleo de carnaúba para uso como biolubrificante

Lubricant is responsible for reducing the wear on the friction protect the metal against oxidation, corrosion and dissipates excess heat, making it essential for the balance of a mechanical system, consequently prolonging the useful life of such a system. The origin of lubricating oils is usually mineral being extracted from the petroleum. But the search for a new source of production of lubricants and fuels it is necessary to meet future demands and reduce the possible environmental damage. For this reason, looking alternative means to produce certain products derived from petroleum, such as biodiesel, for example. Returning to the realm of lubricants, also one realizes this need for new raw materials for their production. Vegetable oil is a renewable resource and biodegradable, and its use entails advantages in environmental, social and economic. The development of this project aims to characterize the carnauba oil as a lubricant plant, or biolubricant. To analyze the oil carnauba tests as checking density, flash point, fire point, viscosity, viscosity, acid number, pH, copper corrosion, thermal conductivity and thermal resistivity were developed. In addition, for conducting the wear on the friction and the gradient of the system temperature, the analysis equipment is designed for wear on the friction. Based on these results, it is observed that the oil carnauba show good correlation to its application as biolubricant

Estudo tribológico de biolubrificantes com adição de nanopartículas de óxidos (zinco e cobre)

Currently, vegetable oils have been studied for bio-lubricants base that fits the new environmental standards. Since, in a world full of finite natural resources, mineral oils bring consequences to the environment due to its low biodegradability and toxicity, also it is important to consider that synthetic oils have a high cost The aim of this work is to obtain a biolubricant additived with oxide nanoparticles (ZnO and CuO) for better resistance to friction and wear, which is not toxic to the environment and have better adherence under boundary lubrication. The methodology consisted in the synthesis of bio-lubricants (soybean and sunflower base) by epoxidation reaction. Then, some physical-chemical analysis in bio-lubricants are made to characterize theses lubricants, such as, density, acidity, iodine value, viscosity, viscosity index. Later, the lubricants were additive with nanoparticles. The tribological performance was evaluated by the equipment HFRR (High Frequency Reciprocating Rig) consisting of a wear test ball-plan type. The characterization of wear analysis was performed by SEM / EDS. The results show that bio-lubricants may be synthesized by reaction of epoxidation with good conversion. Tribological point of view, the epoxidized oils are more effective than lubricant additived with the oxide nanoparticles, they had lower coefficients of friction and better rate of film formation in the study. However, because they are environmentally friendly, bio-lubricants gain the relevant importance in tribological field

Obtenção e caracterização de um compósito de poliuretano de mamona e pó de vidro para aplicações em insolantes térmicos

Thermal insulation is used to protect the heated or cooled surfaces by the low thermal conductivity materials. The rigid ricin polyurethane foams (PURM) are used for thermal insulation and depend on the type and concentration of blowing agent. Obtaining PURM occurs by the use of polyol, silicone, catalyst and blowing agent are pre -mixed, reacting with the isocyanate. The glass is reusable, returnable and recyclable heat insulating material, whose time of heat dissipation determines the degree of relaxation of its structure; and viscosity determines the conditions for fusion, operating temperatures, annealing, etc. The production of PURM composites with waste glass powder (PV) represents economical and renewable actions of manufacturing of thermal insulating materials. Based on these aspects, the study aimed to produce and characterize the PURM composites with PV, whose the mass percentages were 5, 10, 20, 30, 40 and 50 wt%. PURM was obtained commercially, while the PV was recycled from the tailings of the stoning process of a glassmaking; when the refining process was applied to obtain micrometer particles. The PURM + PV composites were studied taking into account the standard sample of pure PURM and the influence of the percentage of PV in this PURM matrix. The results of the chemical, physical and morphological characterization were discussed taking into account the difference in the microstructural morphology of the PURM+PV composites and the pure PURM, as well the results of the physicochemical, mechanical e thermophysical tests by values obtained of density, hardness, compressive strength, specific heat, thermal conductivity and diffusivity. In general, the structure of pure PURM showed large, elongated and regular pores, while PURM+PV composites showed irregular, small and rounded pores with shapeless cells. This may have contributed to reducing their mechanical strength, especially for PURM - PV50. The hardness and density were found to have a proportional relationship with the PV content on PURM matrix. The specific heat, thermal diffusivity and thermal conductivity showed proportional relationship to each other. So, this has been realized that the increasing the PV content on PURM matrix resulted in the rise of diffusivity and thermal conductivity and the decrease of the specific heat. However, the values obtained by the PURM composites were similar the values of pure PURM, mainly the PURM-PV5 and PURM-PV10. Therefore, these composites can be applied like thermal insulator; furthermore, their use could reduce the production costs and to preserve the environment

Estudo da incorporação de resíduo industrial polimérico ao CAP

This work presents the incorporation of an industrial polymeric waste into a petroleum asphalt cement with penetration grade 50-60 (CAP 50-60). The main goal of this research is the development of a polymer-modified asphalt, with improvements in its physical properties, in order to obtain a more resistant material to the traffic loads. Furthermore, the use of this polymeric waste will result in economic and environmental benefits. The CAP 50-60 used in this research was kindly supplied by LUBNOR Lubrificantes e Derivados de Petróleo do Nordeste (produced in Fazenda Belém Aracati - Ceará) and the industrial polymeric waste was provided by a button manufacturer industry, located in Rio Grande do Norte state. This polymeric waste represents an environmental problem due to its difficulty in recycling and disposal, being necessary the payment by the industry to a landfill. The difficulty in its reuse is for being this material a termofixed polymer, as a result, the button chips resulting from the molding process cannot be employed for the same purpose. The first step in this research was the characterization of the polymeric waste, using Differential Scanning Calorimetry (DSC) Infrared spectroscopy (IR spectroscopy), and Thermogravimetric analysis (TGA). Based on the results, the material was classified as unsaturated polyester. After, laboratory experiments were accomplished seeking to incorporate the polymeric waste into the asphalt binder according to a 23 experimental factorial design, using as main factors: the polymer content (2%, 7% and 14%), the temperature of the mixture (140 and 180 oC) and the reaction time (20 and 60 minutes). The characterization of the polymer-modified asphalt was accomplished by traditional tests, such as: penetration, ring and ball softening point, viscosity, ductility and flash point temperature. The obtained results demonstrated that the addition of the polymeric waste into the asphalt binder modified some of its physical properties. However, this addition can be considered as a feasible alternative for the use of the polymeric waste, which is a serious environmental and technological problem.

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

Constribuição técnica de um sistema de emulsão inversa a base de óleos vegetais para fluidos de perfuração

The developments in formulating drilling fluids to apply in petroleum fields are based on new technologies and environmental challenges, where the technical performance of a developed drilling fluid is used to produce a minimum environmental impact, showing great economy in costs. It is well known that the potential use of oil-based drilling fluids is limited because these fluids when discharged in the sea do not disperse as much as water-based ones and may form waterproof films in the seabed, having a profound effect on plants and animals living in this environment. The current works have been made in investigating fluids called pseudofluids, which are synthetic ester-based, n-paraffin-based and other fluids formed from inverse emulsion. In this research the principal parameters involved in inverse emulsion process were studied, in laboratory scale, using esters as main component. Others commercial drilling fluids were used as comparative samples, as well as samples from laboratory and field where these drilling fluids are being applied. Concentrations of emulsifier and organophilic clay, which are viscosity donor, were varied to verify the influence of these parameters, in different oil/water ratios (55/45, 60/40, 65/35, 70/30, and 75/25). The salt concentration (NaCl) is an indicative parameter of stability and activity of an esterbased fluid. In this research the salt concentration was varied in 10,000, 20,000, and 50,000 ppm of NaCl. Some rheological properties of the produced fluids were studied, such as: initial gel, plastic viscosity, yield point, and apparent viscosity. Through the obtained rheological measures, the existence of two systems could be verified: fluid and flocculated. It could be noticed that the systems were influenced, directly, by the oil/water ratio and emulsifier, organophilic clay and NaCl concentrations. This study showed the viability to use an ester obtained from a regional vegetable product babaçu coconut oil to obtain an efficient and environmental safe drilling fluid

Caracterização físico-química, reológica e sensorial de iogurte obtido pela mistura dos leites bubalino e caprino

Milk from different animals can be used for dairy production. Yoghurt is a popular fermented milk product and considered to be one of the greatest importance in terms of consumer acceptance and consumption. The present research deals with the production of strawberry set-type yoghurt by mixing goat and buffalo s milk and it has the objective of taking advantage of the intrinsic characteristics of each milk to produce a final product with desirable attributes. It was conducted by analyzing five experimental groups with different proportions of goat and buffalo s milk: C 100% goat s milk; 7C3B - 70% goat s milk and 30% buffalo s milk, 5C5B - 50% goat s milk and 50% buffalo s milk, 3C7B 30% goat s milk and 70% buffalo s milk; B - 100% buffalo s milk. Each group was evaluated for total solids content and the acidification profile was monitored every 30 minutes by pH analysis. The yoghurt samples were analyzed for physical-chemical (pH, acidity, protein, fat, total and reducing sugars, ash and total solids), rheological (syneresis and viscosity) and sensory characteristics (appearance, odor, consistency and flavour). Samples with higher percentual of bubaline milk reached Vm faster, but the time necessary for pH 4.6 (Te) were similar between groups. Statistical differences (p<0.05) were observed for fat and total solids content of yoghurt, with superior values for groups higher proportions of buffalo s milk. The parameters of behavior reached by the model of Ostwald of Waale pointed yoghurt samples as non-Newtonian and pseudoplastic fluids. Yoghurt made only with goat s milk (C) had higher values (p<0.05) for syneresis, which can be explained by its fragile coagulum. Additionally, this group also had the lowest sensory scores for the attributes consistence and taste, while bubaline yoghurt (B) obtained the best acceptance indexes for all of the appraised parameters

Aplicação de ultrassons no deslocamento de petróleo em meio poroso

The objective of this study was to evaluate the displacement of petroleum/diesel solutions, at different concentrations, observing the effect of ultrasonic vibrations in fluids present in porous media to obtain an increase in oil production. The bubbles produced by ultrasound implode asymmetrically in the rock, generating liquid jets with high speed, displacing the oil present in porous media. The oil/diesel solutions were prepared with concentrations ranging from 20 g/L to 720 g/L in oil in relation to diesel and its viscosities were obtained in a Brookfield Rheometer RS2000, with temperature ranging from 25 to 55 °C. After, calculations were performed to obtain the activation energy data for oil/diesel solutions. For oil recovery experiments, cylindrical samples of porous rock (core samples), with resin around the perimeter and its two circular bases free to allow the passage of fluids, were first saturated with 2% KCl solution and after with oil solutions. The results of oil extraction were satisfactory for all studied solutions, being obtained up to 68% partial displacement with saline solution injection. The ultrasound system was used after saline injection, increasing oil displacement, with oil extractions ranging from 63% to 79%. During the experiments, it was observed the warming of core samples, helping to reduce the viscosity of more concentrated systems, and consequently enhancing the percentage of advanced recovery for all studied solutions

Remediação de solos contaminados com óleo diesel utilizando um sistema de lavagem com microemulsão

The underground reservoirs of fuel retailing system represent an environmental threat, because once in bad conservation, these tanks allow fuel leakage and infiltration. For soil contaminated with fuel, such as diesel oil, the present study introduces the microemulsion systems used by the method of washing. In tests carried out in column with a sample of sandy soil artificially contaminated and previously characterized as to its void level to porosity, to permeability which is an important parameter concerning the study of the method of washing. While microemulsions were characterized for their viscosity and wettability, a variation of active matter was also done departing from the original formulation. The hydraulic diffusivity of the microemulsion was studied so as the injection of such fluid in a soil with sandy characteristics. The results of the extractions revealed the excellent performance of these systems which get to remove around 95% of diesel fuel. This proves the efficiency of the microemulsion in the process of removal of diesel fuel from the soil with the advantage of being a system easily obtainable and less aggressive to the environment when compared to organic solvents.

Extração de ferro da cera de carnaúba utilizando sistemas microemulsionados

The constant search for biodegradable materials for applications in several fields shows that carnauba wax can be a viable alternative in the manufacturing of biolubricants. Carnauba wax is the unique among the natural waxes to have a combination of properties of great importance. In previous studies it was verified the presence of metals in wax composition that can harm the oxidative stability of lubricants. Considering these factors, it was decided to develop a research to evaluate iron removal from carnauba wax, using microemulsion systems (Me) and perform the optimization of parameters, such as: extraction pH, temperature, extraction time, among others. Iron concentration was determined by atomic absorption and, to perform this analysis, sample digestion in microwave oven was used, showing that this process was very efficient. It was performed some analysis in order to characterize the wax sample, such as: attenuated total reflectance infrared spectroscopy (ATR-IR), thermogravimetry (TG), differential scanning calorimetry (DSC), energy dispersive X-ray fluorescence (EDXRF), scanning electron microscopy (SEM) and melting point (FP). The microemulsion systems were composed by: coconut oil as surfactant, n-butanol as cosurfactant, kerosene and/or heptanes as oil phase, distilled water as water phase. The pH chosen for this study was 4.5 and the metal extraction was performed in finite experiments. To evaluate Me extraction it was performed a factorial design for systems with heptane and kerosene as oil phase, also investigating the influence of temperature time and wax/Me ratio, that showed an statistically significant answer for iron extraction at 95% confidence level. The best result was obtained at 60°C, 10 hours contact time and 1: 10 wax/Me ratio, in both systems with kerosene and heptanes as oil phase. The best extraction occurred with kerosene as oil phase, with 54% iron removal