O efeito da lignina residual e dos ácidos hexenurônicos na geração de organoclorados com dióxido de cloro
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Data
2016-07-06
Autores
Frigieri, Tânia Cristina [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
A indústria de papel e celulose é uma das que mais colaboram na contaminação do meio ambiente por compostos organoclorados, principalmente nos processos de branqueamento da polpa. Por isso, o objetivo geral do presente trabalho foi a análise dos organoclorados gerados no efluente de branqueamento (AOX) realizado em duas partes: PRIMEIRA PARTE - produzir três polpas celulósicas proveniente do cozimento kraft, com diferentes quantidades de lignina e ácidos hexenurônicos, e verificar os efeitos que estas têm em relação a geração de AOX no efluente de uma sequência de pré-branqueamento DE. Para a realização deste estudo, foram utilizados cavacos híbridos de Eucalyptus urograndis no cozimento kraft. Após, foram separadas três amostras de polpa marrom, em que uma foi produzida a polpa TRL onde foi realizado o tratamento para retirada da lignina e em outra amostra, o tratamento para retirar os ácidos hexenurônicos, para obter a polpa TRH. Nas três amostras de polpas: marrom, TRL e TRH, foi realizado o pré-branqueamento (sequência DE) com diferentes fatores kappa para análise da quantidade de AOX gerado nos efluentes. Nas polpas foram analisados: alvura, teor de lignina e teor de ácidos hexenurônicos. Os resultados obtidos indicaram que a lignina, quando comparada aos ácidos hexenurônicos, é o que gera maior quantidade de AOX no efluente e também maior quantidade de AOX por número kappa inicial de cada polpa. Os ácidos hexenurônicos dificultaram a retirada da lignina insolúvel da polpa e a lignina não influenciou na remoção dos ácidos hexenurônicos da polpa. Em relação a alvura adquirida na polpa, a lignina influencia no decréscimo do ganho de alvura quando comparado ao ácidos hexenurônicos. SEGUNDA PARTE – comparar uma sequência de branqueamento convencional – OD0(E+P)D1P e uma sequência curta proposta - OAHTDP através da quantidade de AOX gerado no efluente total de branqueamento. Nesta etapa do estudo, foi utilizada a polpa industrial de eucalipto pré-deslignificada com oxigênio para dar continuidade a sequência referência D0(E+P)D1P e a sequência curta proposta - AHTDP, ambas com a alvura objetivo estabelecida de 90± 0,5%ISO. Conclui-se que a sequência referência D0(E+P)D1P gerou mais AOX do que a sequência curta proposta - AHTDP e que a reversão de alvura da sequência referência foi 1,57% ISO enquanto que para a sequência AHTDP foi de 1,88% ISO. Conclui-se, portanto, que a sequência curta proposta AHTDP causou menor impacto ambiental por causa da menor quantidade de AOX gerado no efluente de branqueamento.
The pulp and paper industry is one that collaborate the most in environmental contamination by organochlorine compounds, mainly in pulp bleaching processes. Therefore, the general objective of this study was the analysis of organochlorines generated in the bleaching effluent (AOX) held in two parts: FIRST PART - produce three pulps from the kraft cooking, with different amounts of lignin and HexA's, and check the effects they have compared the generation of AOX in effluents from a sequence of pre-bleaching. For this study, hybrid chips were used Eucalyptus urograndis in kraft cooking. After three samples were separated brownstock, wherein a TRL pulp was produced which was carried out the treatment for the removal of lignin and other sample processing to remove hexenuronic acids, for TRH pulp. All three samples pulps: brownstock, TRH and TRL, pre-whitening (sequence DE) with different kappa factors for analyzing the amount of AOX in effluents generated was performed. The pulps were analyzed: brightness, lignin content and content HexA's. The results showed that lignin compared to HexA's, is what generates greater amount of AOX in the effluent and also increased amount of AOX by initial kappa number of each pulp. The HexA's hindered the removal of insoluble pulp lignin and lignin did not influence the removal of HexA's pulp. Regarding the brightness acquired in the pulp, lignin influences the decrease in brightness gain compared to HexA's. SECOND PART - compare a conventional bleaching sequence - OD0(E+P)D1P and a short motion sequence - OAHTDP through the AOX emissions generated total bleach effluent. In this study phase, industrial pulp predelignified eucalyptus oxygen was used to continue the reference sequence D0(E+P)D1P and short motion sequence - AHTDP, both the brightness established goal of 90 ± 0.5 %ISO. It follows that the reference sequence D0(E+P)D1P AOX generated more than the short proposed sequence - AHTDP and that the brightness reversion of the reference sequence was 1.57%ISO while for AHTDP sequence was 1, 88%ISO. It follows, therefore, that the short motion sequence AHTDP caused less environmental impact because of the lower amount of AOX generated in the bleach effluent.
The pulp and paper industry is one that collaborate the most in environmental contamination by organochlorine compounds, mainly in pulp bleaching processes. Therefore, the general objective of this study was the analysis of organochlorines generated in the bleaching effluent (AOX) held in two parts: FIRST PART - produce three pulps from the kraft cooking, with different amounts of lignin and HexA's, and check the effects they have compared the generation of AOX in effluents from a sequence of pre-bleaching. For this study, hybrid chips were used Eucalyptus urograndis in kraft cooking. After three samples were separated brownstock, wherein a TRL pulp was produced which was carried out the treatment for the removal of lignin and other sample processing to remove hexenuronic acids, for TRH pulp. All three samples pulps: brownstock, TRH and TRL, pre-whitening (sequence DE) with different kappa factors for analyzing the amount of AOX in effluents generated was performed. The pulps were analyzed: brightness, lignin content and content HexA's. The results showed that lignin compared to HexA's, is what generates greater amount of AOX in the effluent and also increased amount of AOX by initial kappa number of each pulp. The HexA's hindered the removal of insoluble pulp lignin and lignin did not influence the removal of HexA's pulp. Regarding the brightness acquired in the pulp, lignin influences the decrease in brightness gain compared to HexA's. SECOND PART - compare a conventional bleaching sequence - OD0(E+P)D1P and a short motion sequence - OAHTDP through the AOX emissions generated total bleach effluent. In this study phase, industrial pulp predelignified eucalyptus oxygen was used to continue the reference sequence D0(E+P)D1P and short motion sequence - AHTDP, both the brightness established goal of 90 ± 0.5 %ISO. It follows that the reference sequence D0(E+P)D1P AOX generated more than the short proposed sequence - AHTDP and that the brightness reversion of the reference sequence was 1.57%ISO while for AHTDP sequence was 1, 88%ISO. It follows, therefore, that the short motion sequence AHTDP caused less environmental impact because of the lower amount of AOX generated in the bleach effluent.
Descrição
Palavras-chave
Celulose, Branqueamento, Impacto ambiental, Cellulose, Bleaching, Environmental impact