Made available in DSpace on 2014-12-17T15:01:20Z (GMT). No. of bitstreams: 1 LenitaSLF.pdf: 2627101 bytes, checksum: 55e09659bccdbe036d1c49a7fea4b6ca (MD5) Previous issue date: 2009-09-03 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico / The treatment of wastewaters contaminated with oil is of great practical interest and it is fundamental in environmental issues. A relevant process, which has been studied on continuous treatment of contaminated water with oil, is the equipment denominated MDIF? (a mixer-settler based on phase inversion). An important variable during the operation of MDIF? is the water-solvent interface level in the separation section. The control of this level is essential both to avoid the dragging of the solvent during the water removal and improve the extraction efficiency of the oil by the solvent. The measurement of oil-water interface level (in line) is still a hard task. There are few sensors able to measure oil-water interface level in a reliable way. In the case of lab scale systems, there are no interface sensors with compatible dimensions. The objective of this work was to implement a level control system to the organic solvent/water interface level on the equipment MDIF?. The detection of the interface level is based on the acquisition and treatment of images obtained dynamically through a standard camera (webcam). The control strategy was developed to operate in feedback mode, where the level measure obtained by image detection is compared to the desired level and an action is taken on a control valve according to an implemented PID law. A control and data acquisition program was developed in Fortran to accomplish the following tasks: image acquisition; water-solvent interface identification; to perform decisions and send control signals; and to record data in files. Some experimental runs in open-loop were carried out using the MDIF? and random pulse disturbances were applied on the input variable (water outlet flow). The responses of interface level permitted the process identification by transfer models. From these models, the parameters for a PID controller were tuned by direct synthesis and tests in closed-loop were performed. Preliminary results for the feedback loop demonstrated that the sensor and the control strategy developed in this work were suitable for the control of organic solvent-water interface level / O tratamento de ?guas residuais contaminadas com ?leo ? um assunto de grande interesse pr?tico, principalmente no que se refere ?s quest?es ambientais. Um processo bastante relevante que vem sendo estudado no tratamento semi-cont?nuo de ?guas contaminadas com ?leo ? o Misturador-Decantador ? Invers?o de Fases (MDIF?). Uma vari?vel importante na opera??o do sistema MDIF? ? o n?vel da interface solvente org?nico/?gua na se??o de separa??o. O controle deste n?vel ? essencial tanto para evitar o arraste de solvente pela ?gua como para melhorar a efici?ncia de remo??o do ?leo pelo solvente. A despeito disso, a medida (em linha) da interface de separa??o ainda constitui uma tarefa dif?cil e s?o poucos os sensores capazes de medir tal interface. No caso de sistemas em escala de bancada, n?o h? sensores de interface com dimens?es compat?veis. O presente trabalho teve como objetivo implementar um sistema de controle de n?vel para a interface de separa??o (solvente org?nico/?gua) no equipamento MDIF?. A medida de n?vel da interface ? baseada na aquisi??o e tratamento de imagens obtidas dinamicamente por uma c?mera (webcam). A estrat?gia de controle foi desen olvida para operar em modo feedback, onde a medida de n?vel obtida pelo sensor de imagem ? comparada ao n?vel desejado e a a??o de controle ? tomada sobre uma v?lvula, seguindo uma lei do tipo PID. Um programa de aquisi??o de dados e controle foi desenvolvido em Fortran para realizar as seguintes tarefas: aquisi??o de imagem, identifica??o da interface solvente org?nico/?gua, tomada de decis?es, envio dos sinais de controle e registro de dados em arquivo. Alguns experimentos em malha aberta foram realizados, onde perturba??es aleat?rias tipo pulso foram aplicadas na vari?vel de entrada (vaz?o de sa?da de ?gua). As respostas do n?vel de interface permitiram a identifica??o do processo atrav?s de modelos de fun??o de transfer?ncia. A partir destes modelos, os par?metros para o controlador PID foram sintonizados por s?ntese direta e testes em malha fechada foram realizados. Os resultados preliminares da malha feedback demonstraram que o sensor e a estrat?gia de controle desenvolvidos neste trabalho foram satisfat?rios para controlar o n?vel da interface solvente org?nico/?gua