Selectivity Studies of Oxygen and Chlorine Dioxide in the Pre-Delignification Stages of a Hardwood Pulp Bleaching Plant
Autor(a) principal: | |
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Data de Publicação: | 2001 |
Outros Autores: | , , |
Tipo de documento: | Artigo |
Idioma: | eng |
Título da fonte: | Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) |
Texto Completo: | http://hdl.handle.net/10316/10520 https://doi.org/10.1021/ie0103613 |
Resumo: | This work is concerned with the role of oxygen on the selectivity of chlorine dioxide in the pre-delignification stage of a E. globulus pulp bleaching plant. Its main purpose is to study the selectivity of chlorine dioxide when applied to an oxygen pre-delignified hardwood kraft pulp and to compare it to that of a conventional pre-delignification with chlorine dioxide (D). The intrinsic viscosity and kappa number were used to follow the polysaccharides degradation and the delignification rates. In an oxygen stage (O), the selectivity varies with the degree of delignification. In the initial fast phase of reaction it exhibits values similar to those of chlorine dioxide in a conventional pre-delignification stage (D), although it diminishes drastically in the second, slow phase of reaction. On the other hand, chlorine dioxide in a conventional pre-delignification stage (D) is a very selective agent and its selectivity remains practically constant along the process. Moreover, it's shown that it is independent of the initial viscosity and kappa number of pulp. However, when chlorine dioxide is applied to a previously oxygen delignified pulp, its selectivity decreases gradually with the extent of delignification in the preceding oxygen stage. The experiments suggest that the global selectivity of an OD sequence with Eucalyptus globulus kraft pulp can be improved if the delignification with oxygen is limited to the fast phase of reaction, which corresponds to the first 5−10 min of reaction. |
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Selectivity Studies of Oxygen and Chlorine Dioxide in the Pre-Delignification Stages of a Hardwood Pulp Bleaching PlantThis work is concerned with the role of oxygen on the selectivity of chlorine dioxide in the pre-delignification stage of a E. globulus pulp bleaching plant. Its main purpose is to study the selectivity of chlorine dioxide when applied to an oxygen pre-delignified hardwood kraft pulp and to compare it to that of a conventional pre-delignification with chlorine dioxide (D). The intrinsic viscosity and kappa number were used to follow the polysaccharides degradation and the delignification rates. In an oxygen stage (O), the selectivity varies with the degree of delignification. In the initial fast phase of reaction it exhibits values similar to those of chlorine dioxide in a conventional pre-delignification stage (D), although it diminishes drastically in the second, slow phase of reaction. On the other hand, chlorine dioxide in a conventional pre-delignification stage (D) is a very selective agent and its selectivity remains practically constant along the process. Moreover, it's shown that it is independent of the initial viscosity and kappa number of pulp. However, when chlorine dioxide is applied to a previously oxygen delignified pulp, its selectivity decreases gradually with the extent of delignification in the preceding oxygen stage. The experiments suggest that the global selectivity of an OD sequence with Eucalyptus globulus kraft pulp can be improved if the delignification with oxygen is limited to the fast phase of reaction, which corresponds to the first 5−10 min of reaction.American Chemical Society2001-11-28info:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/articlehttp://hdl.handle.net/10316/10520http://hdl.handle.net/10316/10520https://doi.org/10.1021/ie0103613engIndustrial & Engineering Chemistry Research. 40:24 (2001) 5680-56850888-5885Barroca, Maria J. M. C.Marques, Pedro J. T. S.Seco, Isabel M.Castro, José Almiro A. M.info:eu-repo/semantics/openAccessreponame:Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)instname:Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informaçãoinstacron:RCAAP2020-05-29T09:42:38Zoai:estudogeral.uc.pt:10316/10520Portal AgregadorONGhttps://www.rcaap.pt/oai/openaireopendoar:71602024-03-19T20:59:19.768407Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) - Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informaçãofalse |
dc.title.none.fl_str_mv |
Selectivity Studies of Oxygen and Chlorine Dioxide in the Pre-Delignification Stages of a Hardwood Pulp Bleaching Plant |
title |
Selectivity Studies of Oxygen and Chlorine Dioxide in the Pre-Delignification Stages of a Hardwood Pulp Bleaching Plant |
spellingShingle |
Selectivity Studies of Oxygen and Chlorine Dioxide in the Pre-Delignification Stages of a Hardwood Pulp Bleaching Plant Barroca, Maria J. M. C. |
title_short |
Selectivity Studies of Oxygen and Chlorine Dioxide in the Pre-Delignification Stages of a Hardwood Pulp Bleaching Plant |
title_full |
Selectivity Studies of Oxygen and Chlorine Dioxide in the Pre-Delignification Stages of a Hardwood Pulp Bleaching Plant |
title_fullStr |
Selectivity Studies of Oxygen and Chlorine Dioxide in the Pre-Delignification Stages of a Hardwood Pulp Bleaching Plant |
title_full_unstemmed |
Selectivity Studies of Oxygen and Chlorine Dioxide in the Pre-Delignification Stages of a Hardwood Pulp Bleaching Plant |
title_sort |
Selectivity Studies of Oxygen and Chlorine Dioxide in the Pre-Delignification Stages of a Hardwood Pulp Bleaching Plant |
author |
Barroca, Maria J. M. C. |
author_facet |
Barroca, Maria J. M. C. Marques, Pedro J. T. S. Seco, Isabel M. Castro, José Almiro A. M. |
author_role |
author |
author2 |
Marques, Pedro J. T. S. Seco, Isabel M. Castro, José Almiro A. M. |
author2_role |
author author author |
dc.contributor.author.fl_str_mv |
Barroca, Maria J. M. C. Marques, Pedro J. T. S. Seco, Isabel M. Castro, José Almiro A. M. |
description |
This work is concerned with the role of oxygen on the selectivity of chlorine dioxide in the pre-delignification stage of a E. globulus pulp bleaching plant. Its main purpose is to study the selectivity of chlorine dioxide when applied to an oxygen pre-delignified hardwood kraft pulp and to compare it to that of a conventional pre-delignification with chlorine dioxide (D). The intrinsic viscosity and kappa number were used to follow the polysaccharides degradation and the delignification rates. In an oxygen stage (O), the selectivity varies with the degree of delignification. In the initial fast phase of reaction it exhibits values similar to those of chlorine dioxide in a conventional pre-delignification stage (D), although it diminishes drastically in the second, slow phase of reaction. On the other hand, chlorine dioxide in a conventional pre-delignification stage (D) is a very selective agent and its selectivity remains practically constant along the process. Moreover, it's shown that it is independent of the initial viscosity and kappa number of pulp. However, when chlorine dioxide is applied to a previously oxygen delignified pulp, its selectivity decreases gradually with the extent of delignification in the preceding oxygen stage. The experiments suggest that the global selectivity of an OD sequence with Eucalyptus globulus kraft pulp can be improved if the delignification with oxygen is limited to the fast phase of reaction, which corresponds to the first 5−10 min of reaction. |
publishDate |
2001 |
dc.date.none.fl_str_mv |
2001-11-28 |
dc.type.status.fl_str_mv |
info:eu-repo/semantics/publishedVersion |
dc.type.driver.fl_str_mv |
info:eu-repo/semantics/article |
format |
article |
status_str |
publishedVersion |
dc.identifier.uri.fl_str_mv |
http://hdl.handle.net/10316/10520 http://hdl.handle.net/10316/10520 https://doi.org/10.1021/ie0103613 |
url |
http://hdl.handle.net/10316/10520 https://doi.org/10.1021/ie0103613 |
dc.language.iso.fl_str_mv |
eng |
language |
eng |
dc.relation.none.fl_str_mv |
Industrial & Engineering Chemistry Research. 40:24 (2001) 5680-5685 0888-5885 |
dc.rights.driver.fl_str_mv |
info:eu-repo/semantics/openAccess |
eu_rights_str_mv |
openAccess |
dc.publisher.none.fl_str_mv |
American Chemical Society |
publisher.none.fl_str_mv |
American Chemical Society |
dc.source.none.fl_str_mv |
reponame:Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) instname:Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informação instacron:RCAAP |
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Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informação |
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RCAAP |
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RCAAP |
reponame_str |
Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) |
collection |
Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) |
repository.name.fl_str_mv |
Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) - Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informação |
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1799133884190818304 |