OZONE BLEACHING AT NEUTRAL PH – A NEW CONCEPT
Autor(a) principal: | |
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Data de Publicação: | 2006 |
Outros Autores: | , , |
Tipo de documento: | Artigo |
Idioma: | por |
Título da fonte: | Ciência Florestal (Online) |
Texto Completo: | https://periodicos.ufsm.br/cienciaflorestal/article/view/1889 |
Resumo: | The effect of medium consistency ozone stage pH was evaluated for brown and oxygen delignified eucalyptus kraft pulp samples obtained from VCP - Luiz Antônio pulp mill. These samples were used as such or previously treated with the hot acid stage (A). The main objective of this study was to determine the viability of increasing the ozone stage pH aiming at decreasing bleaching variable costs. The ozone stage was studied in the pH range of 2.5-9.0, taking into account some important variables which affect ozone bleaching: (1) pulp kappa number entering the ozone stage, (2) reactivity of ozone towards lignin versus hexenuronic acids (HexA´s), (3) pulp treatments prior to ozone stage (acid hydrolysis), and (4) pulp treatments after the ozone stage (extraction or a chlorine dioxide stage). Therefore, the impact of ozone stage pH was investigated in bleaching process such as Z/DEop vs AZ/DEop, Z/DEopD vs AZ/DEopD, Z/E vs AZ/E. The results were interpreted based on ozone stage efficiency and selectivity, and overall bleaching performance measured by the total bleaching chemical consumption required to achieve full brightness, pulp quality and environmental impact. It was concluded that the increase of ozone stage pH from 2.5 to 7.0 has a slightly negative impact on the efficiency and selectivity, measured after Z/DEop sequence, but this effect is not expressive in the end of Z/DEopD bleaching sequence. The increase of ozone stage pH from 2.5 to 7.0 in the sequence Z/DEopD is cost-effective at industrial level because it represents expressive reduction of sulphuric acid and caustic soda demand for pH control in the bleaching plant. These gain areas achieved without any significant changes in pulp quality and effluent load discharge. Nevertheless, the increase of ozone stage pH from 2.5 to 7.0 has a very high negative impact on the efficiency and selectivity for the Z/E and AZ/E processes and it is not recommended in such cases. |
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OZONE BLEACHING AT NEUTRAL PH – A NEW CONCEPTBranqueamento com ozônio em pH neutro – um novo conceito.ligno-celullosic pulpozonehexenuronic acidsacid hydrolysis.polpa ligno-celulósicaozônioácidos hexenurônicoshidrólise ácidaThe effect of medium consistency ozone stage pH was evaluated for brown and oxygen delignified eucalyptus kraft pulp samples obtained from VCP - Luiz Antônio pulp mill. These samples were used as such or previously treated with the hot acid stage (A). The main objective of this study was to determine the viability of increasing the ozone stage pH aiming at decreasing bleaching variable costs. The ozone stage was studied in the pH range of 2.5-9.0, taking into account some important variables which affect ozone bleaching: (1) pulp kappa number entering the ozone stage, (2) reactivity of ozone towards lignin versus hexenuronic acids (HexA´s), (3) pulp treatments prior to ozone stage (acid hydrolysis), and (4) pulp treatments after the ozone stage (extraction or a chlorine dioxide stage). Therefore, the impact of ozone stage pH was investigated in bleaching process such as Z/DEop vs AZ/DEop, Z/DEopD vs AZ/DEopD, Z/E vs AZ/E. The results were interpreted based on ozone stage efficiency and selectivity, and overall bleaching performance measured by the total bleaching chemical consumption required to achieve full brightness, pulp quality and environmental impact. It was concluded that the increase of ozone stage pH from 2.5 to 7.0 has a slightly negative impact on the efficiency and selectivity, measured after Z/DEop sequence, but this effect is not expressive in the end of Z/DEopD bleaching sequence. The increase of ozone stage pH from 2.5 to 7.0 in the sequence Z/DEopD is cost-effective at industrial level because it represents expressive reduction of sulphuric acid and caustic soda demand for pH control in the bleaching plant. These gain areas achieved without any significant changes in pulp quality and effluent load discharge. Nevertheless, the increase of ozone stage pH from 2.5 to 7.0 has a very high negative impact on the efficiency and selectivity for the Z/E and AZ/E processes and it is not recommended in such cases.Foram avaliados o efeito do pH da ozonólise, a média consistência, em amostras industriais (fibra curta de eucalipto) de polpa marrom e pré-deslignificada com oxigênio (pré-O2) obtidas na VCP - Unidade Luiz Antônio, tratadas ou não com um estágio de hidrólise ácida (A). O objetivo principal do estudo foi determinar a viabilidade de se elevar o pH da etapa da ozonólise, visando a reduzir o custo variável de fabricação. O estágio da ozonólise foi estudado numa ampla faixa de pH (2,5-9,0), considerando-se alguns fatores importantes: (1) número kappa da polpa que entra na ozonólise, (2) tratamento da polpa previamente à ozonólise (hidrólise ácida), (3) tratamento da polpa após a ozonólise (extração, dioxidação) e (4) relação lignina/HexA´s que compõe o número kappa. Assim, o pH da ozonólise foi investigado em processos de branqueamento tais como Z/DEopD e AZ/DEopD, Z/E e AZ/E, Z/DEop e AZ/DEop. Os resultados foram interpretados com base na eficiência, seletividade da ozonólise e na performance global do branqueamento, medida pelo consumo de reagentes químicos, qualidade da polpa e impacto ambiental. Concluiu-se que o aumento do pH da ozonólise de 2,5 para 7,0 tem impacto ligeiramente negativo na eficiência e na seletividade do processo, medidas após Z/DEop, mas esse efeito desaparece ao final do branqueamento pela seqüência Z/DEopD. A elevação do pH de 2,5 para 7,0 é justificável em nível industrial, visto que representa redução apreciável dos consumos de ácido sulfúrico e soda caústica para controle de pH na planta de branqueamento. O aumento do pH da ozonólise de 2,5 para 7,0 tem impacto muito negativo na eficiência e na seletividade dos processos Z/E e AZ/E.Universidade Federal de Santa Maria2006-03-30info:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersionapplication/pdfhttps://periodicos.ufsm.br/cienciaflorestal/article/view/188910.5902/198050981889Ciência Florestal; Vol. 16 No. 1 (2006); 71-88Ciência Florestal; v. 16 n. 1 (2006); 71-881980-50980103-9954reponame:Ciência Florestal (Online)instname:Universidade Federal de Santa Maria (UFSM)instacron:UFSMporhttps://periodicos.ufsm.br/cienciaflorestal/article/view/1889/1135Carvalho, Fernando deAsbahr, DenisGodoy, Antonio A. R.Colodette, Jorge Luizinfo:eu-repo/semantics/openAccess2017-05-15T17:40:53Zoai:ojs.pkp.sfu.ca:article/1889Revistahttp://www.ufsm.br/cienciaflorestal/ONGhttps://old.scielo.br/oai/scielo-oai.php||cienciaflorestal@ufsm.br|| cienciaflorestal@gmail.com|| cf@smail.ufsm.br1980-50980103-9954opendoar:2017-05-15T17:40:53Ciência Florestal (Online) - Universidade Federal de Santa Maria (UFSM)false |
dc.title.none.fl_str_mv |
OZONE BLEACHING AT NEUTRAL PH – A NEW CONCEPT Branqueamento com ozônio em pH neutro – um novo conceito. |
title |
OZONE BLEACHING AT NEUTRAL PH – A NEW CONCEPT |
spellingShingle |
OZONE BLEACHING AT NEUTRAL PH – A NEW CONCEPT Carvalho, Fernando de ligno-celullosic pulp ozone hexenuronic acids acid hydrolysis. polpa ligno-celulósica ozônio ácidos hexenurônicos hidrólise ácida |
title_short |
OZONE BLEACHING AT NEUTRAL PH – A NEW CONCEPT |
title_full |
OZONE BLEACHING AT NEUTRAL PH – A NEW CONCEPT |
title_fullStr |
OZONE BLEACHING AT NEUTRAL PH – A NEW CONCEPT |
title_full_unstemmed |
OZONE BLEACHING AT NEUTRAL PH – A NEW CONCEPT |
title_sort |
OZONE BLEACHING AT NEUTRAL PH – A NEW CONCEPT |
author |
Carvalho, Fernando de |
author_facet |
Carvalho, Fernando de Asbahr, Denis Godoy, Antonio A. R. Colodette, Jorge Luiz |
author_role |
author |
author2 |
Asbahr, Denis Godoy, Antonio A. R. Colodette, Jorge Luiz |
author2_role |
author author author |
dc.contributor.author.fl_str_mv |
Carvalho, Fernando de Asbahr, Denis Godoy, Antonio A. R. Colodette, Jorge Luiz |
dc.subject.por.fl_str_mv |
ligno-celullosic pulp ozone hexenuronic acids acid hydrolysis. polpa ligno-celulósica ozônio ácidos hexenurônicos hidrólise ácida |
topic |
ligno-celullosic pulp ozone hexenuronic acids acid hydrolysis. polpa ligno-celulósica ozônio ácidos hexenurônicos hidrólise ácida |
description |
The effect of medium consistency ozone stage pH was evaluated for brown and oxygen delignified eucalyptus kraft pulp samples obtained from VCP - Luiz Antônio pulp mill. These samples were used as such or previously treated with the hot acid stage (A). The main objective of this study was to determine the viability of increasing the ozone stage pH aiming at decreasing bleaching variable costs. The ozone stage was studied in the pH range of 2.5-9.0, taking into account some important variables which affect ozone bleaching: (1) pulp kappa number entering the ozone stage, (2) reactivity of ozone towards lignin versus hexenuronic acids (HexA´s), (3) pulp treatments prior to ozone stage (acid hydrolysis), and (4) pulp treatments after the ozone stage (extraction or a chlorine dioxide stage). Therefore, the impact of ozone stage pH was investigated in bleaching process such as Z/DEop vs AZ/DEop, Z/DEopD vs AZ/DEopD, Z/E vs AZ/E. The results were interpreted based on ozone stage efficiency and selectivity, and overall bleaching performance measured by the total bleaching chemical consumption required to achieve full brightness, pulp quality and environmental impact. It was concluded that the increase of ozone stage pH from 2.5 to 7.0 has a slightly negative impact on the efficiency and selectivity, measured after Z/DEop sequence, but this effect is not expressive in the end of Z/DEopD bleaching sequence. The increase of ozone stage pH from 2.5 to 7.0 in the sequence Z/DEopD is cost-effective at industrial level because it represents expressive reduction of sulphuric acid and caustic soda demand for pH control in the bleaching plant. These gain areas achieved without any significant changes in pulp quality and effluent load discharge. Nevertheless, the increase of ozone stage pH from 2.5 to 7.0 has a very high negative impact on the efficiency and selectivity for the Z/E and AZ/E processes and it is not recommended in such cases. |
publishDate |
2006 |
dc.date.none.fl_str_mv |
2006-03-30 |
dc.type.driver.fl_str_mv |
info:eu-repo/semantics/article info:eu-repo/semantics/publishedVersion |
format |
article |
status_str |
publishedVersion |
dc.identifier.uri.fl_str_mv |
https://periodicos.ufsm.br/cienciaflorestal/article/view/1889 10.5902/198050981889 |
url |
https://periodicos.ufsm.br/cienciaflorestal/article/view/1889 |
identifier_str_mv |
10.5902/198050981889 |
dc.language.iso.fl_str_mv |
por |
language |
por |
dc.relation.none.fl_str_mv |
https://periodicos.ufsm.br/cienciaflorestal/article/view/1889/1135 |
dc.rights.driver.fl_str_mv |
info:eu-repo/semantics/openAccess |
eu_rights_str_mv |
openAccess |
dc.format.none.fl_str_mv |
application/pdf |
dc.publisher.none.fl_str_mv |
Universidade Federal de Santa Maria |
publisher.none.fl_str_mv |
Universidade Federal de Santa Maria |
dc.source.none.fl_str_mv |
Ciência Florestal; Vol. 16 No. 1 (2006); 71-88 Ciência Florestal; v. 16 n. 1 (2006); 71-88 1980-5098 0103-9954 reponame:Ciência Florestal (Online) instname:Universidade Federal de Santa Maria (UFSM) instacron:UFSM |
instname_str |
Universidade Federal de Santa Maria (UFSM) |
instacron_str |
UFSM |
institution |
UFSM |
reponame_str |
Ciência Florestal (Online) |
collection |
Ciência Florestal (Online) |
repository.name.fl_str_mv |
Ciência Florestal (Online) - Universidade Federal de Santa Maria (UFSM) |
repository.mail.fl_str_mv |
||cienciaflorestal@ufsm.br|| cienciaflorestal@gmail.com|| cf@smail.ufsm.br |
_version_ |
1799944126984093696 |