الفهرس 
Bagasse as a promising source for pulp industry.Only 14 pages are availabe for public view
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Abstract
Environmental protection is of an increased interest in
recent years. As a prerequiste, a strong need to find another alternative pulping process rather
those of sulphur and chlorine contained chemicals is elaborated.
Research has intensified in recent years on organic solvent pulping processes to supplement or
reduce the conventional pulping processes. Organosolv pulping methods has drawn our attention
towards the use of peroxyacetic acid pulping techniques.
The present work describes a method for obtaining fully bleached paper-type pulp in an oxidative
peroxyacid process, followed by simple alkaline peroxide bleaching without using either sulphur or
chlorine-based chemicals.
The scope study is focused to the use of peroxyacetic acid in the pulping of cane sugar bagasse
that promises to become a major fibrous raw material in Egypt. A systematic study of bagasse
peroxyacetic acid pulping had been carried out in the following techniques:
One-stage peroxyacetic acid pulping:
The first peroxyacetic acid pulping experiments consisted
of one-stage peroxyacetic acid pulping. The process variables, in this technique, were peroxyacetic
acid concentration (30-60% based on raw material weight), pulping temperature (75-85°C), pulping
time ( 1-3 hours) and liquor ratio 7: I. To summarize the results of one-stage peroxyacetic acid
pulping, high degree of delignification and good defibration were achieved with screened pulp
yields more than 45%, the kappa number ranged from 7 to
21 and degree of polymerization ranged from 620 to 765,
depending largely on the peroxyacetic acid concentration and the pulping temperature. The
optimum conditions of one-stage
peroxyacetic acid pulping had been suggested on the basis of moderate peroxyacetic acid
concentration, in the studied range, at low pulping temperature, 75°C.
With one-stage peroxyacetic acid pulping it was noted
that an extremely high peroxyacetic acid is needed. In an attempt to reduce this excessive high
peroxyacid demand we conducted a series of experiments consisting of various two and three-stage
peroxyacetic pulping.
Two-stage peroxyacetic acid pulping (AcOHJPAA):
Bagasse is first subjected to acetic acid treatment and then
treated with peroxyacetic acid. The optimization of the first stage had been achieved by studying
the pretreatment parameters, acetic acid concentration 80-90%, temperature 90-120°C, time 1-
3 hours, liquor ratio 4: 1 10:1 and the addition of sulphuric acid as an activator. The
optimum conditions of the pretreatment stage, AcOH stage, are 80% AcOH, 110°C, 120 min and 7:1
liquor-to-bagasse ratio. The addition of sulphuric acid (0.05- 0.1%, based on raw material weight)
in the acetic acid stage affected negatively the degree of polymerization and the strength
properties of the produced pulps. To investigate the second stage variables, the first stage
conditions were kept constant at the optimum conditions. The main variables affecting the second
stage are the peroxyacetic acid concentration, pulping time and temperature. It was found that, the
optimum concentration of peroxyacetic acid used in the second stage ranged from 16 to 18%, based
on raw material weight, at the pulping temperature 85°C for 120 min at liquor-to-bagasse ratio 7:
I.
Two-stage peroxyacetic acid pulping (PAA/AcOH):
Bagasse was treated firstly to 16% peroxyacetic acid at
85°C for 120 min at liquor-to-bagasse ratio 7: I, and then subjected to 80% acetic acid at 110°C
for 120 min at liquor-to bagasse 7:1. The produced pulp fromPAA/AcOHhasslightly lower kappa number
and higher brightness than that produced