Navegando por Assunto "Ciclo de vida"

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Acesso aberto (Open Access)
Metodologia de gestão do ciclo de vida de reatores
(Universidade Federal do Pará, 2014-09-05) BELTRÃO, Vanessa de Cássia Viana Martins; VIEIRA, João Paulo Abreu; http://lattes.cnpq.br/8188999223769913
In electric power systems, the shunt reactors are the equipment responsible for the reduction or even cancellation of undesirable capacitive effects in the operation of the lines. Then one realizes the importance of such equipment and the need to keep them running smoothly. A major fault generates a high cost of corrective maintenance, drop in performance indicators, in addition to fines by the regulator - Agência Nacional de Energia Elétrica - ANEEL.The life cycle of a shunt reactor involves eight steps - Planning, Specification, Procurement, Fabrication, Installation, Commissioning, Operation and Decommissioning. In this work will be addressed aspects only of the management of the exploration phase, which includes the set of processes and operation maintained according to the perspectives of the company where this study was conducted. The aging of the reactor can occur in various ways, however the lifetime of a reactor is mainly conditioned by two factors: the speed of aging and loss of robustness of its materials and components, and the operating conditions imposed on it over time. To avoid damage to the reactors, the electric companies have adopted procedures for preventive and predictive maintenance, which, when based on diagnoses of different evaluation methods have a fundamental impact on the life and reliability of the reactors. As a condition of degradation of a reactor is a continuous process in time, this can be classified into five stages: new, normal, abnormal, defective and failed. A condition index (CI) can be attributed to each of these stages of degradation, according to results of diagnostic tests to analyze the state of reactor operation and estimation of its current position in relation to its life cycle. This dissertation deals with the development of a methodology for the systematic analysis by combining fourteen different diagnostic methods and map the results to a model of condition that guide the life cycle of the reactor. The methodology was applied in ten reactors of 500 kV in two Eletrobras-Eletronorte substations in Transmission System of Pará, company where this study was conducted.
Acesso aberto (Open Access)
Um modelo de avaliação de fluxos de biomassa e carbono em madeireiras de comunidades isoladas da região amazônica
(Universidade Federal do Pará, 2010-10-29) MARIALVA, Elden de Albuquerque; BRASIL, Augusto César de Mendonça; http://lattes.cnpq.br/0571960641751286; GUERRA, Danielle Regina da Silva; http://lattes.cnpq.br/6750321690921056
The Amazon Region has a huge amount of biomass resources. The Brazilian Amazon comprises an area larger than 5 million km2, which represents 61% of the Brazilian territory. The Brazilian northern region produces 72.45% of the produced round wood in Brazil; the State of Pará shares 55.47% of that production. Generally, in Amazon region the lumbers get into the forest to select the logs to being cut. Some years later they return again to the same area to harvest again, and the interval time reduces each year. The Amazon region contained 833 sawmills in 1998. These sawmills were located mainly in the Amazon estuary (71%). These wood producers share 1.3 million cubic meters of wood logs (5% of production Amazon). The present work estimated the carbon balance of sawmills in the Amazon River estuary. A life cycle analysis was developed to estimate the carbon balance of the studied sawmills. The study was focused on the wood products considering the process used in small Amazonian communities. There is a well-defined path of the natural resource (biomass/wood) such as: forestry, transportation of biomass, transformation (business/timber) / processes, generation and use of wastes, transport of processed timber, marketing. The energy balance was also analyzed through the flow (inputs and outputs) of wood and carbon during the cycle. A numerical model was developed to simulate the flow of carbon, energy, wood and area affected by exploitation. This work developed a specific model for the evaluation of the carbon flow, the environmental impact assessment was reached, where it shown a positive value, a carbon capture about 55 tCO2/month, even with a low production efficiency system, around 36%. The results show that the current operating system does not pollute but could be improved to achieve higher efficiency in the production process. The waste generated was approximately 64% of the volume of wood entering the mill, its application could be managed to generate approximately 1240 kilowatts of electricity monthly.