Investigação da degradação do óleo presente em fluido de corte por bactérias e fungos

• Ano de defesa: 2015
• Autor(a) principal: Nakagawa, Danielle Hiromi
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Tecnológica Federal do Paraná; Apucarana; Londrina; Brasil; Programa de Pós-Graduação em Engenharia Ambiental; UTFPR
• Palavras-chave em Português: Fluidos em metaloplastia; Óleos vegetais; Contaminação microbiana; Metal-working lubricants; Vegetable oils; Microbial contamination; CNPQ::ENGENHARIAS::ENGENHARIA SANITARIA; Engenharia Sanitária
• Link de acesso: http://repositorio.utfpr.edu.br/jspui/handle/1/2250

The cutting fluid is widely used in metal machining process, but it is vulnerable to microbiological contamination contributing to loss in quality causing the decrease of its useful lifetime. Considering that many papers study the microbiological contamination of the fluid, but few associated to chemical changes of the oil constituent of the fluid, the objective of this study was to monitor the growth of microorganisms in two cutting fluids bases each containing a type of oil (mineral and vegetable) under two operating conditions of the machine tool: normal process and process using a electrophysical catalyst which directs the flow of ozone to the cutting fluid, to evaluate the chemical changes of the fluid oil extracted and the capability of microorganisms to degrade the cutting fluid and the oil extracted. Counting and isolation of bacteria and fungi were performed on cutting fluids used in machine tool throughout 166 hours of operation of the machine. For analysis of oil quality, it was extracted oil of the cutting fluid and posteriorly it was measured the acidity index (mineral and vegetable oils), iodine and saponification of vegetable oil. For the hydrocarbon degradation test it was used 2,6-dichlorophenol-indophenol as degradation indicator, being carbon sources: cutting fluid and oil extracted from the cutting fluid at different times of use of the machine. The results demonstrated that the amount of bacteria and fungi present in the mineral cutting fluid operated on the machine for 126 hours was in the order of 105 to 102 CFU/ml, respectively, and using the catalyst (40 hours of machine operation) it was 106 and 101 CFU/mL, respectively. The amount of bacteria and fungi from vegetable cutting fluid were 102 CFU/ml and after the application of the catalyst they were 105 and 103 CFU/ml, respectively. In the degradation tests of hydrocarbon, it was found that 42% of bacteria and 84% of the fungi were able to degrade the mineral cutting fluid or extracted oil on 5 days of analysis. 54% of bacteria and 74% of the fungi found on vegetable cutting fluid were able to degrade the cutting fluid or extracted oil. It can be concluded that there were chemical changes in the oils used to prepare cutting fluid and that microorganisms can be directly influenced in oil degradation, since the increased amount of microorganisms followed the oil degradation.