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Abstract(s)
O objectivo do presente trabalho foi caracterizar os condensados produzidos numa fábrica de pasta para papel
para identificar e localizar pontos da sua
contaminação.
Para o efeito, foram recolhidas amostras de condensado e caracterizados os
parâmetros condutividade, pH, sódio e sílica. A amostragem decorreu no período entre 15
de Setembro a 6 de Novembro de 2008.
Através da análise dos resultados obtidos para as concentrações de sílica e de sódio
de cada uma das correntes, foram identificadas como contaminadas as correntes de
condensado provenientes do condensador do Turbogerador 4, da área dos Digestores
Descontínuos, da Evaporação e do Aquecedor de Água Quente para o Branqueamento. A
realização de um balanço pontual à sílica no tanque de condensados da Central permitiu
concluir que a maior contribuição advém do condensador do Turbogerador 4. Na
Evaporação ocorre contaminação do condensado quando as secções do Concentrador 1
são colocadas em serviço após lavagem. Durante o acompanhamento do arranque da
Evaporação, uma das secções (1/B) registou um valor máximo na concentração de sódio no
condensado de 135 mg/L Na.
Do estudo resulta, enquanto não for reparado e/ou substituído o equipamento
responsável pelas contaminações, a necessidade de admitir requisitos para controlo da
qualidade da água da caldeira menos restritivos, nomeadamente para a razão sódio/fosfato.
É necessário, contudo, o rigoroso acompanhamento da qualidade da água da caldeira (pH,
sobretudo) para prevenir afastamentos inesperados dos limites de controlo.
Durante a realização deste trabalho foram identificadas algumas situações a
melhorar, tais como a uniformização dos valores de desvio para esgoto dos condensados e
das unidades utilizadas, a adequação das escalas dos aparelhos de medida para as gamas
de leitura de interesse, a verificação e calibração periódica do equipamento instalado em
linha, a adopção do parâmetro “Sódio” para controlo da qualidade dos condensados, a
instalação de sistemas de amostragem com arrefecimento em todas as correntes de
condensados e a reparação ou substituição de algum equipamento instalado em linha que
se encontra em muito mau estado e ainda a manutenção do equipamento mantendo-o em
boas condições de limpeza.
The purpose of this study was to characterize the condensate produced in a paper pulp industrial plant to identify and locate points of its contamination. For the purpose, samples of condensate were collected and characterized the parameters of conductivity, pH, sodium and silica. Sampling took place between the period of 15 September and 6 November 2008. By analyzing the results for concentrations of silica and sodium in each of the currents were identified as contaminated the streams of condensate from the condenser of TG4, from the area of discontinuous digesters, from the evaporation and from the hot water heater for bleaching. By performing a punctual balance of silica in the condensate tank central showed that the largest contribution comes from the condenser TG4. During evaporation the contamination of the condensate occurs when the sections of the concentrator 1 are placed in service after washing. During follow-up of the onset of evaporation, one of the sections (1/B) reached a peak in the concentration of sodium in the condensate of 135 mg/L Na. From the results of the study we may conclude that while the equipment responsible for the contamination is not repaired and/or replaced, there is the need to admit less restrictive requirements for the control of the boilers water, especially for the ratio sodium/phosphate. It is necessary, however, a strict monitoring of the quality of boilers water (pH, mainly) to prevent unexpected deviations of the limits control. During the performing of this work some situations needing improvement were identified, such as the standardization of the values of sewage diversion of the condensate and the units used, the appropriateness of scales of measurement devices for the range of reading interests, verification and periodic calibration equipment installed in-line, adopting the parameter "Sodium" for quality control of condensate, the installation of sampling systems with cooling in all currents of condensates and the repairing or replacement or substitution of any equipment installed in the line that is in a very bad state and finally the maintenance of the equipment keeping it in a clean condition.
The purpose of this study was to characterize the condensate produced in a paper pulp industrial plant to identify and locate points of its contamination. For the purpose, samples of condensate were collected and characterized the parameters of conductivity, pH, sodium and silica. Sampling took place between the period of 15 September and 6 November 2008. By analyzing the results for concentrations of silica and sodium in each of the currents were identified as contaminated the streams of condensate from the condenser of TG4, from the area of discontinuous digesters, from the evaporation and from the hot water heater for bleaching. By performing a punctual balance of silica in the condensate tank central showed that the largest contribution comes from the condenser TG4. During evaporation the contamination of the condensate occurs when the sections of the concentrator 1 are placed in service after washing. During follow-up of the onset of evaporation, one of the sections (1/B) reached a peak in the concentration of sodium in the condensate of 135 mg/L Na. From the results of the study we may conclude that while the equipment responsible for the contamination is not repaired and/or replaced, there is the need to admit less restrictive requirements for the control of the boilers water, especially for the ratio sodium/phosphate. It is necessary, however, a strict monitoring of the quality of boilers water (pH, mainly) to prevent unexpected deviations of the limits control. During the performing of this work some situations needing improvement were identified, such as the standardization of the values of sewage diversion of the condensate and the units used, the appropriateness of scales of measurement devices for the range of reading interests, verification and periodic calibration equipment installed in-line, adopting the parameter "Sodium" for quality control of condensate, the installation of sampling systems with cooling in all currents of condensates and the repairing or replacement or substitution of any equipment installed in the line that is in a very bad state and finally the maintenance of the equipment keeping it in a clean condition.
Description
Keywords
Contaminação de condensados Água de caldeiras Condutividade pH Concentração de sódio e de sílica Contaminated condensate Boilers water Conductivity Sodium and silica concentration
Pedagogical Context
Citation
Publisher
Instituto Politécnico do Porto. Instituto Superior de Engenharia do Porto