Desenvolvimento de um sistema para medição do espectro de impedância em fluidos

• Ano de defesa: 2017
• Autor(a) principal: Przysiada, Felipe Augusto
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Tecnológica Federal do Paraná; Curitiba; Brasil; Programa de Pós-Graduação em Engenharia Elétrica e Informática Industrial; UTFPR
• Palavras-chave em Português: Análise eletroquímica; Impedância (Eletricidade); Medidas elétricas - Automação; Engenharia elétrica; Electrochemical analysis; Impedance (Electricity); Electric measurements - Automation; Electric engineering; CNPQ::ENGENHARIAS::ENGENHARIA ELETRICA::MEDIDAS ELETRICAS, MAGNETICAS E ELETRONICAS INSTRUMENTACAO::MEDIDAS ELETRICAS; Engenharia Elétrica
• Link de acesso: http://repositorio.utfpr.edu.br/jspui/handle/1/2790

The need to monitor the behavior of substances is fundamental in several areas of the industry, such as the analysis of reactions in chemical reactors or the investigation of flows with multiple components, such as in the oil and gas extraction. Impedance spectroscopy, where the electrical impedance of a substance is analyzed at different frequencies, is a candidate technique and its use is spread mainly in laboratories focused on research in the area of analytical chemistry. However, this technique is still only limitedly applied for monitoring industrial processes. Hence, this work aims at the development of a simple and low-cost system based on impedance spectroscopy with possible applications in industrial activities. Initially several techniques for obtaining the impedance spectrum were reviewed. For the implementation, we opted for the use of the chirp multifrequency signal in the range of 1 Hz to 495 kHz for excitation and the transimpedance amplifier circuit for receiving the signals of substances. In addition, two sensor variations were used for a more comprehensive investigation of the system operation. The developed system consists of data reception software on the computer, connected directly to a microcontrolled sensing electronics, in charge of the generation and sampling of the signals from the sensor. To validate the system, measurements were made with reference impedance (resistors and capacitors) as well as the system was applied to measure various known substances, such as air, water, silicon oil and isopropanol. In comparison with theoretical values, the results of the system proved to be appropriate for the identification of different substances by measuring the frequency response of the impedance. As an example of application, the system was applied to monitor the ice formation process, where was possible to verified the transition from liquid to ice water. In this way, the system can be applied in future work to monitor other processes.