Fractionation of birch wood in MiBK-water-ethanol system

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Journal Title

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Volume Title

Kemian tekniikan korkeakoulu | Master's thesis

Date

2015-03-03

Department

Major/Subject

Renewable Materials Engineering

Mcode

KM3002

Degree programme

Master's Programme in Bioproduct Technology

Language

en

Pages

67+2

Series

Abstract

The objective of this thesis was to separate the birch wood into cellulose, hemicellulose and lignin. Clean fractionation (CF) was considered a promising method for the organosolv biomass fractionation. The lignocellulosic material was separated with a ternary mixture of methyl isobutyl ketone, ethanol and water in the presence of sulphuric acid at temperature of 140˚C. In order to understand the feasibility and applicability of this organosolv fractionation process, mass balances on the primary polymers were analyzed. The overall mass balances of the resulting solids, organics and aqueous fractions were examined. Different analytical methods were applied to characterize the three fractions. In the present work, the influences of the fractionation parameters were investigated. Birch woods were cooked at acid concentration of 0.05 M and 0.1 M. It was found that under increased acid concentration, lower values of yields, kappa and viscosity were obtained. No galactose, mannose or arabinose was observed in the cellulose. Glucan contents for cellulose samples of 91.2% using 0.05 M H2SO4 were observed, and rose as high as 97.3% when 0.1 M H2SO4 was used. The aqueous hemicellulose fraction contained a high level of monosugars while in the organic phase, little or no mannose, galactose and arabinose was observed. At 140 °C with 0.1 M H2SO4 and 0.05 M H2SO4 cooked for 71 minutes could separate the main three components efficiently based on the multivariate interactions between time, acid concentration and the properties measured for each of the isolated process streams.

Description

Supervisor

Herbert, Sixta

Thesis advisor

Borrega, Marc

Keywords

biorefinery, clean fractionation, dissolving pulp, organosolv

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