Origin of yield loss in chemical pulp bleaching

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dc.contributor Aalto-yliopisto fi
dc.contributor Aalto University en
dc.contributor.advisor Fearon, Olesya
dc.contributor.advisor Kuitunen, Susanna
dc.contributor.author Lê, Huy
dc.date.accessioned 2014-01-10T09:37:10Z
dc.date.available 2014-01-10T09:37:10Z
dc.date.issued 2013-12-03
dc.identifier.uri https://aaltodoc.aalto.fi/handle/123456789/12036
dc.description.abstract The goal of this thesis was to determine the origin of the yield loss of kraft pulps in each bleaching stage in an Elemental Chlorine Free (ECF) bleaching sequence, including oxygen delignification (O), acid hydrolysis (A), chlorine dioxide bleaching (D), alkaline extraction with oxidative reinforcement (Ep) and peroxide bleaching (P). The literature review was elaborated on reactions of different pulps components, namely lignin, carbohydrates and hexenuronic acid (HexA), with bleaching chemicals, with emphasis on carbohydrates degradation. Effects of bleaching conditions on pulp yield loss were also considered. Laboratory bleaching experiments (O-D0+Ep-D1-P) of softwood kraft pulps (85% pine, 15% spruce) provided by a Finnish pulp mill were done at the conditions similar to those used at the supplying mill. For each stage, pre- and post-bleached pulps were analysed for HexA content, viscosity and kappa number. Bleaching effluents were analysed for Total Organic Carbon (TOC) and lignin contents. Yield losses during bleaching were 2.4, 2.8, 0.6 and 0.5% for O-, D0+Ep-, D1- and P-stages, respectively. Combined yield losses of lignin and HexA were translated into kappa number reduction, which was close to the change in measured kappa numbers. Significant carbohydrate degradation was observed in Ep- and P-stages due to the wash-away of Mg2+ ions. en
dc.format.extent 50+3
dc.format.mimetype application/pdf en
dc.language.iso en en
dc.title Origin of yield loss in chemical pulp bleaching en
dc.type G2 Pro gradu, diplomityö en
dc.contributor.school Kemian tekniikan korkeakoulu fi
dc.subject.keyword kraft pulp en
dc.subject.keyword yield loss en
dc.subject.keyword bleaching en
dc.subject.keyword lignin en
dc.subject.keyword hexenuronic acid en
dc.subject.keyword carbohydrate en
dc.identifier.urn URN:NBN:fi:aalto-201401101112
dc.programme.major Biorefineries fi
dc.programme.mcode KM3001 fi
dc.type.ontasot Master's thesis en
dc.type.ontasot Diplomityö fi
dc.contributor.supervisor Vuorinen, Tapani
dc.programme Master's Programme in Bioproduct Technology fi
dc.location PK fi

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