O ambientalismo econômico no discurso da reciclagem dos materiais

O modelo civilizatório da sociedade global fundamenta-se na produção à larga escala e no aumento exponencial e diversificado do consumo. Este modelo impacta o meio ambiente já que demanda grandes quantidades de recursos naturais e provoca contaminação ambiental. No leque desta contaminação, a geração de resíduos sólidos surge como uma das principais devido a seus efeitos nocivos serem sentidos de forma imediata pelas pessoas. Em países como o Brasil, uma das soluções requeridas para se minimizar e/ou equacionar a problemática engendrada pelos resíduos sólidos é a reciclagem dos materiais. A justificativa oficial pelo esforço à reciclagem está nas características da atividade já que o uso de materiais reciclados reduz a demanda por recursos naturais em processos produtivos industriais, aumenta o tempo de vida útil dos aterros sanitários (local de destino final dos resíduos), além de gerar emprego e renda para os catadores, sujeitos que sobrevivem da coleta e separação dos materiais recicláveis. A partir de uma ética ambiental, a pergunta que deve ser feita quando nos propomos a analisar as implicações da geração dos resíduos é: por que a sociedade global gera resíduos sólidos de maneira acentuada? Contudo, à luz dos pressupostos mercadológicos do capitalismo, a pergunta que move as discussões acerca da problemática dos resíduos sólidos é: o que fazer com a crescente geração de resíduos sólidos? O presente artigo se propõe a uma reflexão dos elementos justificativos dessa ode à reciclagem. Em nossa perspectiva, a reciclagem fomenta ao que denominamos de ambientalismo econômico, no qual o discurso pró-reciclagem se apropria dos elementos e potencialidades ambientais da atividade da reciclagem para justificar as ações de caráter econômico no que se refere ao que fazer com os resíduos gerados diariamente.

Obtenção de emulsões asfálticas convencionais e modificadas com argilas e nanoargilas

The increasing demand for asphalt leads to the development of techniques that can improve the quality of products and increase the useful working life of pavements. Consequently, there is a growing application of asphalt emulsions, which are produced from a mixture of petroleum asphalt cement (CAP) with an aqueous phase. The main advantage of asphalt emulsions is its cold application, reducing energy costs. Conventional emulsions are obtained using asphalt, water, solvent, and additives. The modified asphalt emulsion is developed by adding a modifying agent to conventional emulsions. These modifiers can be natural fibers, waste polymers, nanomaterials. In this work modified asphalt emulsion were obtained using organoclays. First, it was prepared a conventional asphalt emulsion with the following mass proportion: 50% of 50/70 penetration grade CAP, 0.6% of additives and 3% of emulsifier, 20% of solvent and 26.4% of water. It was used bentonite and vermiculite (1% and 4%) to obtain the modified asphalt emulsion. Bentonite and vermiculite were added in its raw state and as an organoclay form and as an organoclay-acid form, resulting in 26 experimental runs. The methodology described by Qian et al. (2011), with modifications, was used to obtain the organoclay and the organoclay-acid form. infrared spectroscopy (IR)) were used to characterize the clays and nanoclays. The emulsions were prepared in a colloidal mill, using 30 minutes and 1 hour as mixing time. After, the emulsions were characterized. The following tests were performed, in accordance with the Brazilian specifications (DNER- 369/97): sieve analysis, Saybolt Furol viscosity, pH determination, density, settlement and storage stability, residue by evaporation, and penetration of residue. Finally, it can be concluded that the use of nanoclays as asphalt modifiers represent a viable alternative to the road paving industry

O ambientalismo econômico no discurso da reciclagem dos materiais

O modelo civilizatório da sociedade global fundamenta-se na produção à larga escala e no aumento exponencial e diversificado do consumo. Este modelo impacta o meio ambiente já que demanda grandes quantidades de recursos naturais e provoca contaminação ambiental. No leque desta contaminação, a geração de resíduos sólidos surge como uma das principais devido a seus efeitos nocivos serem sentidos de forma imediata pelas pessoas. Em países como o Brasil, uma das soluções requeridas para se minimizar e/ou equacionar a problemática engendrada pelos resíduos sólidos é a reciclagem dos materiais. A justificativa oficial pelo esforço à reciclagem está nas características da atividade já que o uso de materiais reciclados reduz a demanda por recursos naturais em processos produtivos industriais, aumenta o tempo de vida útil dos aterros sanitários (local de destino final dos resíduos), além de gerar emprego e renda para os catadores, sujeitos que sobrevivem da coleta e separação dos materiais recicláveis. A partir de uma ética ambiental, a pergunta que deve ser feita quando nos propomos a analisar as implicações da geração dos resíduos é: por que a sociedade global gera resíduos sólidos de maneira acentuada? Contudo, à luz dos pressupostos mercadológicos do capitalismo, a pergunta que move as discussões acerca da problemática dos resíduos sólidos é: o que fazer com a crescente geração de resíduos sólidos? O presente artigo se propõe a uma reflexão dos elementos justificativos dessa ode à reciclagem. Em nossa perspectiva, a reciclagem fomenta ao que denominamos de ambientalismo econômico, no qual o discurso pró-reciclagem se apropria dos elementos e potencialidades ambientais da atividade da reciclagem para justificar as ações de caráter econômico no que se refere ao que fazer com os resíduos gerados diariamente.

Estudo da molhabilidade de ligas de adição à base de prata sobre insertos cerâmicos para aplicação em brocas perfuração de poços de petróleo

Metal-ceramic interfaces are present in tricone drill bits with hard ceramic inserts for oil well drilling operations. The combination of actions of cutting, crushing and breaking up of rocks results in the degradation of tricone drill bits by wear, total or partial rupture of the drill bit body or the ceramic inserts, thermal shock and corrosion. Also the improper pressfitting of the ceramic inserts on the bit body may cause its total detachment, and promote serious damages to the drill bit. The improvement on the production process of metal-ceramic interfaces can eliminate or minimize some of above-mentioned failures presented in tricone drill bits, optimizing their lifetime and so reducing drilling metric cost. Brazing is a widely established technique to join metal-ceramic materials, and may be an excellent alternative to the common mechanical press fitting process of hard ceramic inserts on the steel bit body for tricone drill bit. Wetting phenomena plays an essential role in the production of metal/ceramic interfaces when a liquid phase is present in the process. In this work, 72Silver-28Copper eutectic based brazing alloys were melted onto zirconia, silicon nitride and tungsten carbide/Co substrates under high vacuum. Contact angle evolution was measured and graphically plotted, and the interfaces produced were analysed by SEM-EDX. The AgCu eutectic alloy did not wet any ceramic substrates, showing high contact angles, and so without chemical interaction between the materials. Better results were found for the systemns containing 3%wt of titanium in the AgCu alloy. The presence os titanium as a solute in the alloy produces wettable cand termodinamically stable compounds, increasing the ceramics wetting beahviour

Desenvolvimento de metodologia de extração e pré-concentração utilizando sistema microemulsionado para determinação de Cd, Co, Cu, Ni, Pb e Tl em águas naturais e produzidas por HR-CS AAS

The determination and monitoring of metallic contaminants in water is a task that must be continuous, leading to the importance of the development, modification and optimization of analytical methodologies capab le of determining the various metal contaminants in natural environments, because, in many cases, the ava ilable instrumentation does not provide enough sensibility for the determination of trace values . In this study, a method of extraction and pre- concentration using a microemulsion system with in the Winsor II equilibrium was tested and optimized for the determination of Co, Cd, P b, Tl, Cu and Ni through the technique of high- resolution atomic absorption spectrometry using a continuum source (HR-CS AAS). The optimization of the temperature program for the graphite furnace (HR-CS AAS GF) was performed through the pyrolysis and atomization curves for the analytes Cd, Pb, Co and Tl with and without the use of different chemical modifiers. Cu and Ni we re analyzed by flame atomization (HR-CS F AAS) after pre-concentr ation, having the sample introduction system optimized for the realization of discrete sampling. Salinity and pH levels were also analyzed as influencing factors in the efficiency of the extraction. As final numbers, 6 g L -1 of Na (as NaCl) and 1% of HNO 3 (v/v) were defined. For the determination of the optimum extraction point, a centroid-simplex statistical plan was a pplied, having chosen as the optimum points of extraction for all of the analytes, the follo wing proportions: 70% aqueous phase, 10% oil phase and 20% co-surfactant/surfactant (C/S = 4). After extraction, the metals were determined and the merit figures obtained for the proposed method were: LOD 0,09, 0,01, 0,06, 0,05, 0,6 and 1,5 μg L -1 for Pb, Cd, Tl, Co, Cu and Ni, re spectively. Line ar ranges of ,1- 2,0 μg L -1 for Pb, 0,01-2,0 μg L -1 for Cd, 1,0 - 20 μg L -1 for Tl, 0,1-5,0 μg L -1 for Co, 2-200 μg L -1 and for Cu e Ni 5-200 μg L -1 were obtained. The enrichment factors obtained ranged between 6 and 19. Recovery testing with the certified sample show ed recovery values (n = 3, certified values) after extraction of 105 and 101, 100 and 104% for Pb, Cd, Cu and Ni respectively. Samples of sweet waters of lake Jiqui, saline water from Potengi river and water produced from the oil industry (PETROBRAS) were spiked and the recovery (n = 3) for the analytes were between 80 and 112% confirming th at the proposed method can be used in the extraction. The proposed method enabled the sepa ration of metals from complex matrices, and with good pre-concentration factor, consistent with the MPV (allowed limits) compared to CONAMA Resolution No. 357/2005 which regulat es the quality of fresh surface water, brackish and saline water in Brazil.

Mecanismo de tolerância a falhas através de escalonamento para uma arquitetura reconfigurável de grão grosso

The continuous evolution of integrated circuit technology has allowed integrating thousands of transistors on a single chip. This is due to the miniaturization process, which reduces the diameter of wires and transistors. One drawback of this process is that the circuit becomes more fragile and susceptible to break, making the circuit more susceptible to permanent faults during the manufacturing process as well as during their lifetime. Coarse Grained Reconfigurable Architectures (CGRAs) have been used as an alternative to traditional architectures in an attempt to tolerate such faults due to its intrinsic hardware redundancy and high performance. This work proposes a fault tolerance mechanism in a CGRA in order to increase the architecture fault tolerance even considering a high fault rate. The proposed mechanism was added to the scheduler, which is the mechanism responsible for mapping instructions onto the architecture. The instruction mapping occurs at runtime, translating binary code without the need for recompilation. Furthermore, to allow faster implementation, instruction mapping is performed using a greedy module scheduling algorithm, which consists of a software pipeline technique for loop acceleration. The results show that, even with the proposed mechanism, the time for mapping instructions is still in order of microseconds. This result allows that instruction mapping process remains at runtime. In addition, a study was also carried out mapping scheduler rate. The results demonstrate that even at fault rates over 50% in functional units and interconnection components, the scheduler was able to map instructions onto the architecture in most of the tested applications.

Estudo da molhabilidade de ligas de adição à base de prata sobre insertos cerâmicos para aplicação em brocas perfuração de poços de petróleo

Metal-ceramic interfaces are present in tricone drill bits with hard ceramic inserts for oil well drilling operations. The combination of actions of cutting, crushing and breaking up of rocks results in the degradation of tricone drill bits by wear, total or partial rupture of the drill bit body or the ceramic inserts, thermal shock and corrosion. Also the improper pressfitting of the ceramic inserts on the bit body may cause its total detachment, and promote serious damages to the drill bit. The improvement on the production process of metal-ceramic interfaces can eliminate or minimize some of above-mentioned failures presented in tricone drill bits, optimizing their lifetime and so reducing drilling metric cost. Brazing is a widely established technique to join metal-ceramic materials, and may be an excellent alternative to the common mechanical press fitting process of hard ceramic inserts on the steel bit body for tricone drill bit. Wetting phenomena plays an essential role in the production of metal/ceramic interfaces when a liquid phase is present in the process. In this work, 72Silver-28Copper eutectic based brazing alloys were melted onto zirconia, silicon nitride and tungsten carbide/Co substrates under high vacuum. Contact angle evolution was measured and graphically plotted, and the interfaces produced were analysed by SEM-EDX. The AgCu eutectic alloy did not wet any ceramic substrates, showing high contact angles, and so without chemical interaction between the materials. Better results were found for the systemns containing 3%wt of titanium in the AgCu alloy. The presence os titanium as a solute in the alloy produces wettable cand termodinamically stable compounds, increasing the ceramics wetting beahviour

Desenvolvimento de pastas de cimento flexíveis para poços de petróleo submetidos à injeção de vapor utilizando látex do tipo SBR

Novel cementing materials formulations containing flexible polymeric admixtures have been studied aiming at improving the mechanical behavior of oil well cement slurries submitted to steam injection. However, research activities in this sector are still under development. The steam injected directly into the well causes casing dilation, which after a reduction in temperature, tends to return to its original dimensions, resulting in crack formation and hydraulic isolation loss of the well, which will result in shortening of well life. In this scenario, the objective of the present study was to evaluate the mechanical behavior of Portland-based slurries containing SBR latex, applied in oil well cementing of wells submitted to steam injection. Were formulated slurries with densities of 1.797 g/cm3 (15.0 lb/Gal) and 1.869 g/cm3 (15.6 lb/Gal), containing admixtures with a latex concentration of 0; 66.88; 133.76; 200.64 and 267.52 L/m3 (0, 0.5, 1.0, 1.5 and 2.0 gpc). Tests including rheology, fluid loss control, thickening time, API compressive strength and splitting tensile strength, beyond steam injection simulation. Microstrutural characteristics of the slurries were also performed (XRD, TG, FTIR and SEM). The results showed that increasing the polymer concentration increased in the rheological properties and fluid loss, and a decrease in the elasticity modulus of the cement slurries. The results obtained showed that the slurries can be applied in cementing operations of oil wells submitted to steam injection.

Influência da adição de cálcio nas propriedades de pastas geopoliméricas destinadas a cimentação de poços de petróleo

Nowadays, the search for new technologies that are able to follow the upcoming challenges in oil industry is a constant. Always trying properties improvements of the used materials, looking for the best performance and greater life time. Besides the search for technologies that show an improvement of performance, the search for materials environmentally correct along the whole production process. In Oil well cementing, this search for new technologies passes through the development of slurry systems that support these requests and that are also environmentally friendly. In this context, the use of geopolymer slurries is a great alternative route to cementing oil wells. Besides having good properties, comparable to Portland cement slurries, this alternative material releases much less CO2 gas in the production of their root materials when compared the production of Portland cement, which releases tons of CO2. In order to improve the properties of geopolymer slurries has been added Calcium Oxide, as observed in other studies that slurries where the Calcium is present the values of compressive strength is greater. The addition has been realized based in the CaO/SiO2 molar ratio of 0.05, 0.10 and 0.15. Have been performed compressive strength tests, thickening time, rheology and fliud loss control test of the slurries, following NBR 9831, as well as the physical chemical characterization of XRD, SEM and TG. Has been observed in most of the tests the slurries follow a tendency until the ratio of 0.10, which inverses in the ratio 0.15. This behavior can be explained by two phenomena that occur simultaneously, the first one is the break of the polymer chains and a consequent increase in molucules mobility, which prevails until the ratio of 0.1, and the second is possible approach of the chains due to the capacity of the calcium ions stabilize the charges of two different aluminum. There is only one linearity in the mechanical behavior that can be attributed to the appereance of the C-S-H phase. Based on this, it is concluded that the phenomenon of breaking the polymer chains predominates until the ratio of 0.1, causing an increase of the filtrate volume, lower rheological parameters and increasing thickening time. From the ratio of 0.15 the approach of the chains predominates, and the behavior is reversed

Nitretação em plasma com gaiola catódica: caracterização e avaliação do desempenho da camada nitretada em facas de corte

Nowadays, in the plastic industry are used mills that accomplish the recycling of residues generated in the production of its components. These mills contain cut sheets that suffer accelerated wear, once they are submitted constantly to the tribologic efforts, decreasing its useful life. To reduce this problem, it s used noble steels or takes place superficial treatments. The ionic nitriding process presents some limitations related to the uniformity of the layer in pieces with complex geometry, committing its application in pieces as knives, head offices, engagements, etc. However, the new technique of nitriding in cathodic cage eliminates some problems, as the restrictions rings, inherent to the conventional ionic nitriding. In present work, was studied the use viabilization of steels less noble, as SAE 1020, SAE 4320 and SAE 4340, nitreded by two different techniques, to substitute the AISI 01 steels, usually used in the cut knifes fabrication, seeking to reduce the costs and at the sane time to increase the useful life of these knifes. The steel most viable was the SAE 4340, nitrided in cathodic cage, because it presented uniformity in thickness and in the hardness of the layer, besides of increased 58% in the average its useful life

Analise SWOT do gerenciamento de resíduos do coco verde em duas agroindústrias do estado do Rio Grande do Norte

In the current conjuncture, the environmental factor has been changing the position of companies that are practicing or minimally adopting environmental management. Such tool has been used by companies to face the problems caused by solid waste, in particular green coconut waste, which is constantly among the material discarded by society (companies/ consumer). It is a typical tropical fruit whose fresh water is very benefic for human health, and its popularization has caused a progressive increase of its consumption. Following this stream of thought, this present work came up with an analysis of strengths, weaknesses, threats, and opportunities SWOT analysis on green coconut solid waste management at two agribusiness companies in the state of Rio Grande do Norte (RN), Brazil, aiming to know the challenges and the potentials of this kind of waste. According to the approach of the problem, this work fits a descriptive, exploratory, and qualitative research. The data collection was obtained by a questionnaire and a structured interview, in order to evaluate the strategic posture of agribusiness companies through SWOT analysis, which is an English acronym for Strengths, Weaknesses, Opportunities and Threats. The SWOT analysis is an effective tool to analyze the internal and external environment of an organization. This tool contributes to locate the company at the environment in question and when well applied it enables the detection of mistakes, the strengthening of correct procedures, the avoidance of threats, and the bet on opportunities. The studied agribusiness industries have very similar profiles, such as a long business life span, and a strategy that extends the useful life of the fruit, by using its waste for the manufacturing of new subproducts. In both, the daily quantity of waste resulted of this process reaches approximately 20 thousand units of the fruit in high season, being necessary a focus directed at use and/or treatment of these waste. Further to SWOT analysis, it was ascertained that the agribusiness company A works through a defensive marketing strategy and acts vulnerably, in other words, unable of acting before this market segment, for it has decided to stop using the waste due to a lack of equipment and technology. On the other hand, the agribusiness company B has incorporated an offensive marketing strategy because even not possessing equipments, technology, and appropriated internal installations, it still insists on use and benefits of green coconut waste in its agribusiness. Thus, it is considered that the potential of green coconut waste management for the production of several subproducts reduces the impacts produced by inappropriate placement and generates profits in a short, medium and long term. Such profits being tangible and intangible, as the interest for sustainability actions is not only a matter of obtaining return on capital, but it is an important question in order to move on into business, since it is not enough to have quality on products and process nowadays. It is necessary to establish socio-environmental practices aiming the image of the company as the prevailing role on consumers buying decision

Nano emulsões aplicadas a recuperação avançada de petróleo

A exploração de petróleo está a cada dia em circunstâncias mais adversas, no que diz respeito à profundidade dos poços como também, em relação à fluidez do óleo. Os reservatórios de descobertas recentes não possuem energia própria para produzir ou os métodos convencionais não são eficientes para fazer com que esses reservatórios tenham uma vida útil elevada, devido a alterações das propriedades físico-químicas, como por exemplo a viscosidade, que torna o deslocamento do óleo pelos poros do reservatório até a superfície cada vez mais complexo. O presente trabalho tem como objetivo estudar a preparação, caracterização e a utilização de nanoemulsões obtidas a partir de sistemas microemulsionados, com e sem a presença de polímero. Esses sistemas foram aplicados como método químico de recuperação de petróleo, com o intuito de obter maior eficiência de volume de óleo deslocado. O interesse por esse tipo de sistema existe devido a sua baixa tensão superficial, o pequeno tamanho de gotícula e, principalmente, pelo baixo percentual de matéria ativa presente em sua composição. Os ensaios realizados para caracterizar esses sistemas foram: aspecto físico, medidas de tamanho de gotícula, índice de polidispersão, tensão superficial, pH e condutividade. Ensaios de reologia e de adsorção dos sistemas foram realizados com o objetivo de avaliar sua influencia na recuperação de petróleo. Os ensaios de recuperação foram realizados em um equipamento que simula as condições de um reservatório de petróleo, utilizando plugs de rocha arenito Botucatu. Esses plugs foram saturados com salmoura (KCl 2%) e com petróleo proveniente da Bacia Potiguar do campo de Ubarana. Após essas etapas foi realizada a recuperação convencional utilizando a salmoura e, por último, foi injetada, a nanoemulsão, como método de recuperação avançada. Os sistemas obtidos variaram de 0% à 0,4% de polímero. Os ensaios de tamanhos de partícula obtiveram como resultado uma variação de 9,22 a 14,8 nm, caracterizando que as nanoemulsões estão dentro da faixa de tamanho inerente a esse tipo de sistema. Para ensaios de tensão superficial os valores foram na faixa de 33,6 a 39,7 dynas/cm, valores semelhantes à microemulsões e bem abaixo da tensão superficial da água. Os resultados obtidos para os valores de pH e condutividade se mantiveram estáveis ao longo do tempo de armazenamento, essa avaliação indica estabilidade das nanoemulsões estudadas. O teste de recuperação avançada utilizando nanoemulsão com baixo percentual de matéria ativa obteve como resultado de eficiência de deslocamento 39,4%. Porém esse valor foi crescente, de acordo com o aumento do percentual de polímero na nanomeulsão. Os resultados de eficiência de deslocamento de petróleo estão diretamente relacionados com o aumento da viscosidade das nanoemulsões. A nanoemulsão V (0,4% polímero) é o sistema mais viscoso dentre os analisados, e obteve o maior percentual de óleo deslocado (76,7%), resultando na maior eficiência de deslocamento total (90%). Esse estudo mostrou o potencial de sistemas nanoemulsionados, com e sem polímeros, na recuperação avançada de petróleo. Eles apresentam algumas vantagens com relação a outros métodos de recuperação avançada, como: o baixo percentual de matéria ativa, baixo índice de adsorção do polímero, dissolvido em nanoemulsão, na rocha e alta eficiência de recuperação

Estudo da reidratação do feijão verde (Vigna unguiculata L. Walp) desidratado por micro-ondas com e sem pré-tratamento osmótico

The green bean has organoleptic and nutritional characteristics that make it an important food source in tropical regions such as the Northeast of Brazil. It is a cheap source of protein and important for nutrition of rural population contributing significantly in subsistence farming of the families from Brazil s northeast. It is consumed in entire region and together with the dry meat and other products composes the menu of typical restaurants, being characterized as an important product for economy of Northeast. The green bean is consumed freshly harvested and has short cycle, being characterized as a very perishable food, which hampers your market. The drying method is an alternative to increase the lifetime and provide a reduction volume of this product making easier your transportation and storage. However is necessary to search ways of drying which keep the product quality not only from the nutritional standpoint but also organoleptic. Some characteristics may change with the drying process such as the coloring, the rehydration capacity and the grains cooking time. The decrease of drying time or of exposure of the grains to high temperature minimizes the effects related with the product quality loss. Among the techniques used to reduce the drying time and improve some characteristics of the product, stands out the osmotic dehydration, widely used in combined processes such as the pretreatment in drying food. Currently the use of the microwaves has been considered an alternative for drying food. The microwave energy generates heat inside of materials processed and the heating is practically instantaneous, resulting in shorter processing times and product quality higher to that obtained by conventional methods. Considering the importance of the green beans for the Northeast region, the wastefulness of production due to seasonality of the crop and your high perishability, the proposal of this thesis is the study of drying grain by microwaves with and without osmotic pretreatment, focusing on the search of conditions of processes which favor the rehydration of the product preserving your organoleptic characteristics. Based on the analysis of the results of osmotic dehydration and dielectric properties was defined the operating condition to be used in pretreatment of the green bean, with osmotic concentration in saline solution containing 12,5% of sodium chloride, at 40°C for 20 minutes. The drying of green bean by microwave was performed with and without osmotic pretreatment on the optimized condition. The osmotic predehydration favored the additional drying, reducing the process time. The rehydration of dehydrated green bean with and without osmotic pretreatment was accomplished in different temperature conditions and immersion time according to a factorial design 22, with 3 repetitions at the central point. According to results the better condition was obtained with the osmotically pretreated bean and rehydrated at a temperature of 60°C for 90 minutes. Sensory analysis was performed comparing the sample of the green bean in natura and rehydrated in optimized conditions, with and without osmotic pretreatment. All samples showed a good acceptance rate regarding the analyzed attributes (appearance, texture, color, odor and taste), with all values above 70%. Is possible conclude that the drying of green bean by microwave with osmotic pretreatment is feasible both in respect to technical aspects and rehydration rates and sensory quality of the product

Desenvolvimento de pastas de cimento flexíveis para poços de petróleo submetidos à injeção de vapor utilizando látex do tipo SBR

Novel cementing materials formulations containing flexible polymeric admixtures have been studied aiming at improving the mechanical behavior of oil well cement slurries submitted to steam injection. However, research activities in this sector are still under development. The steam injected directly into the well causes casing dilation, which after a reduction in temperature, tends to return to its original dimensions, resulting in crack formation and hydraulic isolation loss of the well, which will result in shortening of well life. In this scenario, the objective of the present study was to evaluate the mechanical behavior of Portland-based slurries containing SBR latex, applied in oil well cementing of wells submitted to steam injection. Were formulated slurries with densities of 1.797 g/cm3 (15.0 lb/Gal) and 1.869 g/cm3 (15.6 lb/Gal), containing admixtures with a latex concentration of 0; 66.88; 133.76; 200.64 and 267.52 L/m3 (0, 0.5, 1.0, 1.5 and 2.0 gpc). Tests including rheology, fluid loss control, thickening time, API compressive strength and splitting tensile strength, beyond steam injection simulation. Microstrutural characteristics of the slurries were also performed (XRD, TG, FTIR and SEM). The results showed that increasing the polymer concentration increased in the rheological properties and fluid loss, and a decrease in the elasticity modulus of the cement slurries. The results obtained showed that the slurries can be applied in cementing operations of oil wells submitted to steam injection.

Influência da adição de cálcio nas propriedades de pastas geopoliméricas destinadas a cimentação de poços de petróleo

Nowadays, the search for new technologies that are able to follow the upcoming challenges in oil industry is a constant. Always trying properties improvements of the used materials, looking for the best performance and greater life time. Besides the search for technologies that show an improvement of performance, the search for materials environmentally correct along the whole production process. In Oil well cementing, this search for new technologies passes through the development of slurry systems that support these requests and that are also environmentally friendly. In this context, the use of geopolymer slurries is a great alternative route to cementing oil wells. Besides having good properties, comparable to Portland cement slurries, this alternative material releases much less CO2 gas in the production of their root materials when compared the production of Portland cement, which releases tons of CO2. In order to improve the properties of geopolymer slurries has been added Calcium Oxide, as observed in other studies that slurries where the Calcium is present the values of compressive strength is greater. The addition has been realized based in the CaO/SiO2 molar ratio of 0.05, 0.10 and 0.15. Have been performed compressive strength tests, thickening time, rheology and fliud loss control test of the slurries, following NBR 9831, as well as the physical chemical characterization of XRD, SEM and TG. Has been observed in most of the tests the slurries follow a tendency until the ratio of 0.10, which inverses in the ratio 0.15. This behavior can be explained by two phenomena that occur simultaneously, the first one is the break of the polymer chains and a consequent increase in molucules mobility, which prevails until the ratio of 0.1, and the second is possible approach of the chains due to the capacity of the calcium ions stabilize the charges of two different aluminum. There is only one linearity in the mechanical behavior that can be attributed to the appereance of the C-S-H phase. Based on this, it is concluded that the phenomenon of breaking the polymer chains predominates until the ratio of 0.1, causing an increase of the filtrate volume, lower rheological parameters and increasing thickening time. From the ratio of 0.15 the approach of the chains predominates, and the behavior is reversed