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Determinação do teor de compostos aromáticos policíclicos de óleos minerais isolantes para transformadores
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Abstract(s)
Este relatório insere-se na disciplina Dissertação/Estágio do Mestrado de Engenharia Química – Tecnologias de Proteção Ambiental e descreve o estágio de mestrado realizado na empresa EFACEC ENERGIA - Máquinas e Equipamentos Elétricos S.A. e no laboratório GRAQ (Grupo de Reação e Análises Químicas), que integra a rede Requimte, situada no Instituto Superior de Engenharia do Porto.
A EFACEC ENERGIA encontra-se situada em Leça do Balio, S. Mamede Infesta e dedica-se à produção de transformadores e outros equipamentos elétricos. O grupo EFACEC está ligado a várias áreas de negócio: energia, transportes e logística, engenharia, ambiente e serviços. A EFACEC ENERGIA possui um Laboratório de Química onde se realizam vários ensaios químicos e físico-químicos nomeadamente ensaios normalizados pela CEI (Comissão Eletrotécnica Internacional) e pela ASTM (American Society for Testing and Materials).
Este projeto tem como objetivo a quantificação de hidrocarbonetos aromáticos policíclicos (HAP) nos óleos minerais isolantes de transformadores de energia. Os transformadores de energia são máquinas elétricas estáticas que permitem a transferência de energia elétrica de um circuito para outro, e que apresentam como material isolante líquido, o óleo mineral. As propriedades dos óleos são controladas por ensaios laboratoriais, de modo a manter o bom funcionamento dos transformadores de energia. Os HAP são poluentes orgânicos persistentes prejudiciais ao Ambiente e à saúde humana e animal, sendo fundamental a sua determinação. Os HAP foram analisados por cromatografia líquida de alta eficiência (HPLC) e detecção por fluorescência e por arranjo de fotodiodos. Os compostos estudados foram os 16 considerados prioritários pela US EPA (United States Environmental Protection Agency) e outros quatro compostos, dois deles que apareceram em teores elevados nas amostras de óleo estudadas o 1-Metilnaftaleno e o 2-Metilnaftaleno, o Dibenzo(a,l)pireno devido à sua elevada toxicidade e o Benzo(j)fluoranteno por co-eluir com o Benzo(b)fluoranteno.
As amostras foram previamente preparadas utilizando a extração em fase sólida (SPE) e a extração em QuEChERS. Entre as duas metodologias a extração em QuEChERS foi a mais eficiente, económica e rápida.
Os resultados da metodologia analítica foram considerados bons. Nos ensaios obtiveram-se valores de coeficientes de determinação (R2) entre os 0,9960-0,9999 para as várias curvas de calibração; a repetibilidade dos tempos de retenção teve desvios padrão relativos entre os 0,05-0,24 % e nos ensaios recuperação obtiveram-se maioritariamente recuperações entre os 85-125 %.
O método desenvolvido para a análise dos 20 HAP foi aplicado a 5 óleos minerais isolantes de transformadores de energia, 4 deles (X2-X5) eram óleos novos de diferentes fornecedores e o óleo X1 era um óleo envelhecido mas do mesmo fornecedor que o óleo X5.
Os óleos com designações de X1, X2, X3, X4 e X5 apresentaram concentrações totais destes HAP de 276,64 ppm, 194,75 ppm, 88,03 ppm, 343,38 ppm e 174,50 ppm, respetivamente. Os compostos Acenafteno e Indeno(1,2,3-cd)pireno não foram encontrados em nenhum dos óleos e os compostos 1 e 2-Metilnaftaleno, o Fluoreno e o Antraceno são os que têm maiores concentrações. O composto mais tóxico, o Dibenzo(a,l)pireno, apenas aparece nos óleos X1 e X5 em concentrações muito baixas, de 0,66 ppm e 0,60 ppm, respetivamente. Verificou-se que com o processo de envelhecimento de um óleo isolante, neste caso do óleo X1, o teor de HAP aumentou em relação à concentração total de HAP do óleo novo X5.
Os resultados obtidos, tendo em conta os objetivos propostos, foram muito satisfatórios. Resta futuramente estudar outros HAP que possam estar presentes nos óleos minerais isolantes.
This report is part of the discipline Dissertation / Stage Master of Chemical Engineering - Environmental Protection Technologies and describes the stage at the Masters held company EFACEC ENERGY - Machinery and Electric Equipment SA and laboratory GRAQ (Group Reaction and Chemical Analysis) that integrates network Requimte, located at Instituto Superior de Engenharia do Porto. EFACEC ENERGY is located in Leca do Balio, S. Mamede Infesta and is dedicated to the production of transformers and other electrical equipment. The group EFACEC is connected to multiple business areas: energy, transport and logistics, engineering, environment and services. EFACEC ENERGY has a Chemistry Laboratory where they perform various tests chemical and physico-chemical tests including standardized by the IEC (International Electrotechnical Commission) and ASTM (American Society for Testing and Materials). This project aims at the quantification of polycyclic aromatic hydrocarbons (PAHs) in mineral oil insulating power transformers. The power transformers are static electric machines that allow the transfer of electrical energy from one circuit to another, and presenting as liquid insulation material, mineral oil. The properties of the oils are controlled by laboratory tests in order to keep the good functioning of power transformers. PAHs are persistent organic pollutants harmful to the environment and human and animal health, being fundamental to its determination. The PAHs were analyzed by high performance liquid chromatography (HPLC) and fluorescence detection and a photodiode array. The compounds studied were the 16 were considered priorities by the U.S. EPA (United States Environmental Protection Agency) and other four compounds, two of which appeared in high levels in oil samples studied the 1-Methylnaphthalene and 2-Methylnaphthalene, the Dibenzo(a,l)pyrene because of its high toxicity and Benzo(j)fluoranthene by co-elute with Benzo(b)fluoranthene. The samples were previously prepared using solid phase extraction (SPE) and QuEChERS extraction. Between the two methodologies in QuEChERS extraction was the most efficient, economical and fast. The results of the analytical methodology were considered good. In the tests there were obtained values of determination coefficients (R2) between 0.9960 to 0.9999 for different calibration curves; repeatability had retention times relative standard deviation between 0.05 to 0.24 %; recovery assays were obtained mainly recoveries between 85 to 125 %. The method developed for the analysis of PAH 20 was applied to five mineral oils insulating power transformers, four of them (X2-X5) were new oils from different vendors and X1 oil was an oil aged but the same supplier as the oil X5. Oils with designations X1, X2, X3, X4 and X5 showed total concentrations of these PAHs 276.64 ppm, 194.75 ppm, 88.03 ppm, 174.50 ppm and 343.38 ppm, respectively. Compounds Acenaphthene and Indeno(1,2,3-cd)pyrene were not found in any of the oils and the compounds 1 and 2-Methylnaphthalene, Fluorene and Anthracene are those which have higher concentrations. The most toxic compound, the Dibenzo(a,l)pyrene, appears only in oils X1 and X5 very low concentrations of 0.66 ppm and 0.60 ppm, respectively. It was observed that with the aging process of an insulating oil, the oil case X1, content of PAH increased in relation to the total concentration of PAHs new oil X5. The results obtained, taking into account the objectives set were very satisfactory. It remains future study other PAHs that may be present in mineral insulating oils.
This report is part of the discipline Dissertation / Stage Master of Chemical Engineering - Environmental Protection Technologies and describes the stage at the Masters held company EFACEC ENERGY - Machinery and Electric Equipment SA and laboratory GRAQ (Group Reaction and Chemical Analysis) that integrates network Requimte, located at Instituto Superior de Engenharia do Porto. EFACEC ENERGY is located in Leca do Balio, S. Mamede Infesta and is dedicated to the production of transformers and other electrical equipment. The group EFACEC is connected to multiple business areas: energy, transport and logistics, engineering, environment and services. EFACEC ENERGY has a Chemistry Laboratory where they perform various tests chemical and physico-chemical tests including standardized by the IEC (International Electrotechnical Commission) and ASTM (American Society for Testing and Materials). This project aims at the quantification of polycyclic aromatic hydrocarbons (PAHs) in mineral oil insulating power transformers. The power transformers are static electric machines that allow the transfer of electrical energy from one circuit to another, and presenting as liquid insulation material, mineral oil. The properties of the oils are controlled by laboratory tests in order to keep the good functioning of power transformers. PAHs are persistent organic pollutants harmful to the environment and human and animal health, being fundamental to its determination. The PAHs were analyzed by high performance liquid chromatography (HPLC) and fluorescence detection and a photodiode array. The compounds studied were the 16 were considered priorities by the U.S. EPA (United States Environmental Protection Agency) and other four compounds, two of which appeared in high levels in oil samples studied the 1-Methylnaphthalene and 2-Methylnaphthalene, the Dibenzo(a,l)pyrene because of its high toxicity and Benzo(j)fluoranthene by co-elute with Benzo(b)fluoranthene. The samples were previously prepared using solid phase extraction (SPE) and QuEChERS extraction. Between the two methodologies in QuEChERS extraction was the most efficient, economical and fast. The results of the analytical methodology were considered good. In the tests there were obtained values of determination coefficients (R2) between 0.9960 to 0.9999 for different calibration curves; repeatability had retention times relative standard deviation between 0.05 to 0.24 %; recovery assays were obtained mainly recoveries between 85 to 125 %. The method developed for the analysis of PAH 20 was applied to five mineral oils insulating power transformers, four of them (X2-X5) were new oils from different vendors and X1 oil was an oil aged but the same supplier as the oil X5. Oils with designations X1, X2, X3, X4 and X5 showed total concentrations of these PAHs 276.64 ppm, 194.75 ppm, 88.03 ppm, 174.50 ppm and 343.38 ppm, respectively. Compounds Acenaphthene and Indeno(1,2,3-cd)pyrene were not found in any of the oils and the compounds 1 and 2-Methylnaphthalene, Fluorene and Anthracene are those which have higher concentrations. The most toxic compound, the Dibenzo(a,l)pyrene, appears only in oils X1 and X5 very low concentrations of 0.66 ppm and 0.60 ppm, respectively. It was observed that with the aging process of an insulating oil, the oil case X1, content of PAH increased in relation to the total concentration of PAHs new oil X5. The results obtained, taking into account the objectives set were very satisfactory. It remains future study other PAHs that may be present in mineral insulating oils.
Description
Mestrado em Engenharia Química - Ramo Optimização Energética na Indústria Química
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Publisher
Instituto Politécnico do Porto. Instituto Superior de Engenharia do Porto