Bleachability
Mostrando 1-11 de 11 artigos, teses e dissertações.
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1. Wood basic density effect of Eucalyptus grandis in the paper making
ABSTRACT The basic density is the main technical property of the wood due to the fact of the easy determination and correlation with the others wood properties. In this article, it was evaluated wood chips from a five-years-old Eucalyptus grandis in three different silvicultural treatments for pulp and paper production. First, a conventional kraft pulping wa
Matéria (Rio J.). Publicado em: 16/09/2019
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2. INFLUÊNCIA DO CONTEÚDO DE XILANAS NA BRANQUEABILIDADE, PROPRIEDADES HIGROSCÓPICAS, FISICO-MECÂNICAS E ÓPTICA DE POLPAS BRANQUEADAS DE EUCALIPTO
Bleached eucalypt kraft pulps are widely used in print and writing (P&W) and tissue paper manufacture. Among the quality requirements of pulp for these papers, xylan content has been controversial. The objective of this study was to evaluate the influence of xylan content on bleachability, hygroscopic, physic-mechanical and optical properties of the pulp. In
Quím. Nova. Publicado em: 2015-02
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3. A influência dos ácidos hexenurônicos no rendimento e na branqueabilidade da polpa kraft
This study investigated the impact of pulp hexenuronic acids (HexAs) content on pulping yield by changing cooking reaction temperature. The bleachability of pulps containing variable amounts of HexAs was also investigated. The cooking at 170 ºC produced pulp of kappa number, HexAs and screen yield of 16.2, 49.4 mmol/kg and 50.2%, respectively, whereas the c
Química Nova. Publicado em: 2009
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4. Effect of age of the wood of eucalyptus in its chemical and pulpability, and bleachability and properties of the pulp / Efeito da idade da madeira de eucalipto na sua química e polpabilidade, e branqueabilidade e propriedades físicas da polpa
The concern about the quality of the wood that enters a cellulose factory has been focused on many studies, once the productive process and final product are under great influence of the original raw material. Considering the demand for younger trees, the effect of the age of the wood in the chemical constitution and the variables of the process, as well as
Publicado em: 2008
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5. The impact of kappa number composition on eucalyptus kraft pulp bleachability
Consumption of chemicals during ECF bleaching of kraft pulp correlates reasonably well with kappa number, which measures with KMnO4 the total amount of oxidizable material in the pulp. However, the method does not distinguish between the oxidizable material in residual lignin and other structures susceptible to oxidation, such as hexenuronic acids (HexAs), e
Brazilian Journal of Chemical Engineering. Publicado em: 2007-03
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6. Métodos alternativos para aproveitamentos das hemiceluloses da madeira de eucalipto na indústria de celulose kraft / Alternative methods for using eucalyptus wood hemicelluloses in the kraft cellulose industry
The search for a better use of wood in the pulp industry has fuelled interest in a more rational use of its components, particularly hemicelluloses. This study investigates the impacts of alkaline leaching and self-hydrolysis of wood chips for hemicellulose removal, as well as re-adsorption into the fibers during kraft pulping of dissolved wood solids presen
Publicado em: 2007
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7. Treatability of effluents from eucalyptus kraft pulp bleaching with acid hydrolysis/hot chlorine dioxide technologies / Tratabilidade dos efluentes de branqueamento de polpa kraft de eucalipto com tecnologias de hidrólise ácida/dióxido de cloro à quente
The aim of this study was to evaluate the impact of D, D*, A/D* and AD technologies on characteristics and treatabilities of eucalyptus kraft pulp ECF bleaching effluents, of low and high COD, and a full brightness 89-90% ISO. Two samples of eucalyptus kraft pulp pre-delignified in oxygen, a well washed one with COD 6,4 kg/t.a.s. and another not well washed
Publicado em: 2006
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8. Efeito da lixiviação ácida de cavacos de eucalipto no processo Kraft / Effects of acid leaching of wood chips on the Kraft process
The goal of the present work was assessing the influence of acid leaching of wood chips before Kraft cooking, on the yield of the pulping process, the bleachability of the pulp and on its physical and mechanical properties. At first, a study was made to determine optimum conditions to be used in the leaching process: time, temperature and pH. The wood chips
Publicado em: 2006
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9. Relative importance of Eucalyptus spp. wood basic density and chemical composition on yield, bleachability and kraft pulp quality / Importância relativa da densidade básica e da constituição química de madeira de Eucalyptus spp. no rendimento, branqueabilidade e qualidade da polpa kraft
Dez madeiras do gênero Eucalyptus, com idades, espaçamentos e procedências diversas foram transformadas em polpa celulósica kraft marrom de kappa 17-18 e branqueadas até alvura de 90% ISO, utilizando a seqüência ECF de branqueamento O-D-PO-D. As características físicas e químicas das madeiras e das polpas marrons e branqueadas foram medidas e avali
Publicado em: 2004
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10. Modo de ação de xilanases de Aspergillus sp 2M1 em sequencias de branqueamento de polpas de Eucalyptus grandis totalmente livres de cloro
Unbleached Eucalyptus grandis kraft pulps were submitted to TCF bleaching sequences (XOP - Xylanase/Oxygen/Peroxide and XZP -Xylanase/Ozone/Peroxide) using a non-commercial enzyme (Asperzyme 2M1) at the X stage. During the enzymatic treatment, the xylanase charge, inducted carbon source, incubation temperature and incubation time were changed. The pulp sampl
Publicado em: 1999
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11. Cloning of the xynB Gene from Dictyoglomus thermophilum Rt46B.1 and Action of the Gene Product on Kraft Pulp
A two-step PCR protocol was used to identify and sequence a family 11 xylanase gene from Dictyoglomus thermophilum Rt46B.1. Family 11 xylanase consensus fragments (GXCFs) were amplified from Rt46B.1 genomic DNA by using different sets of consensus PCR primers that exhibited broad specificity for conserved motifs within fungal and/or bacterial family 11 xylan
American Society for Microbiology.