Isabel Miranda, Helena Pereira
Kinetics of ASAM and Kraft Pulping of Eucalypt Wood (Eucalyptus globulus)
Summary
The kinetics of ASAM and kraft pulping of eucalypt wood (Eucalyptus globulus) were studied in relation
to delignification and polysaccharide removal. In comparison to kraft, ASAM pulping had lower
mass losses and delignification for the same temperature and reaction times (59.2% at Kappa 25 vs
50.0% at Kappa 17, at 180°C). The ASAM pulps have a higher brightness. ASAM pulping had a short
initial period with no mass loss and lignin removal, followed by two reaction phases: a main phase where
61% of lignin was removed (at 180°C) and a subsequent final phase. In comparison to kraft, the main
delignification rates of ASAM pulping were approximately 2.5 slower (at 180°C, ?1.8 × 10?2 min?1 for
ASAM and ?4.2 × 10?2 for kraft pulping), and the calculated Arrhenius activation energies were higher
(132.4 kJ mol?1 and 83.5 kJ mol?1, respectively). The loss of cellulose was relatively small (12.5 %)
and lower than in kraft pulps.
Holzforschung, Walter de Gruyter
Print ISSN: 0018-3830
Volume: 56, 02/2002
Pages: 85 - 90
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