TY - JOUR

T1 - Estimation of proportions of different pulp types in recycled paper and deinked pulp by acid methanolysis

AU - Sundberg, Anna

AU - Emet, Stefan

AU - Rehn, Patrik

AU - Vähäsalo, Lari

AU - Holmbom, Bjarne

N1 - Copyright:
Copyright 2008 Elsevier B.V., All rights reserved.

PY - 2005

Y1 - 2005

N2 - We have developed and evaluated a method to estimate the proportion of bleached kraft pulp from hardwoods (HP), bleached kraft pulp from softwoods (SP) and mechanical pulp (MP) in deinked pulp (DIP) or recycled paper (RP) by analysis of the sugar units in hemicelluloses and pectins. Different pulps, i.e., HP, SP and MP, were obtained from Nordic pulp mills. The pulps were mixed in different proportions and dried. The content of arabinose, xylose, mannose, galactose, rhamnose, galacturonic acid and 4-O-methyl-glucuronic acid in hemicelluloses and pectins in the different pulps and in the mixtures were determined by acid methanolysis and gas chromatography (GC). The contents of the sugar units were significantly different in the three pulp types, but quite similar in the same pulp type, irrespectively of bleaching sequence. A linear model for estimating the relative proportions of HP, SP and MP in DIP or RP were formulated. Hence, given a predefined set of errors, εi, and data of HP, SP and MP, the relative proportions can be estimated by solving a linear least-squares problem. It was concluded that the proportion of hardwood kraft pulp, softwood kraft pulp and mechanical pulp in deinked pulp or recycled paper can be estimated using a mathematical model based on the contents of the sugar units in hemicelluloses and pectins. The difference between the actual mixing ratio and the estimated values was on average less than ± 5%.

AB - We have developed and evaluated a method to estimate the proportion of bleached kraft pulp from hardwoods (HP), bleached kraft pulp from softwoods (SP) and mechanical pulp (MP) in deinked pulp (DIP) or recycled paper (RP) by analysis of the sugar units in hemicelluloses and pectins. Different pulps, i.e., HP, SP and MP, were obtained from Nordic pulp mills. The pulps were mixed in different proportions and dried. The content of arabinose, xylose, mannose, galactose, rhamnose, galacturonic acid and 4-O-methyl-glucuronic acid in hemicelluloses and pectins in the different pulps and in the mixtures were determined by acid methanolysis and gas chromatography (GC). The contents of the sugar units were significantly different in the three pulp types, but quite similar in the same pulp type, irrespectively of bleaching sequence. A linear model for estimating the relative proportions of HP, SP and MP in DIP or RP were formulated. Hence, given a predefined set of errors, εi, and data of HP, SP and MP, the relative proportions can be estimated by solving a linear least-squares problem. It was concluded that the proportion of hardwood kraft pulp, softwood kraft pulp and mechanical pulp in deinked pulp or recycled paper can be estimated using a mathematical model based on the contents of the sugar units in hemicelluloses and pectins. The difference between the actual mixing ratio and the estimated values was on average less than ± 5%.

KW - Carbohydrates

KW - Constrained Least-Squares Optimization

KW - Deinked Pulp

KW - Gas Chromatography

KW - Hemicelluloses

KW - Parameter Estimation

KW - Pectins

KW - Recycled Paper

UR - http://www.scopus.com/inward/record.url?scp=29344455474&partnerID=8YFLogxK

M3 - Conference article

AN - SCOPUS:29344455474

VL - 2

SP - 361

EP - 365

JO - Appita Annual Conference and Exhibition

JF - Appita Annual Conference and Exhibition

SN - 1443-5454

T2 - 59th Appita Annual Conference and Exhibition, incorporating the 13th ISWFPC: International Symposium on Wood, Fibre and Pulping Chemistry

Y2 - 16 May 2005 through 19 May 2005

ER -