Proceedings Book / Bildiri Kitabı - Orman Fakültesi - Süleyman ...

2 nd International Non-Wood Products Symposium 8-10 September 2011 - Isparta/TURKEY
subsequently combusted in the recovery furnace of
the pulp mill. But these hemicelluloses provide
low heating value than lignin. Pre-extraction of the
hemicelluloses prior to pulping would make these
polysaccharides available for other applications,
such as fermentation to ethanol or butanol
(feedstock for bioenergy) or for conversion to
other bioproducts (Gáspár, et al 2007; Wang et al
2011).
Most cellulose or dissolving pulp comes from
wood using the prehydrolysis kraft or acid sulfite
processes (Biermann 1993, Hinck, et al. 1985).
Dissolving wood pulp is a chemically refined
bleached pulp composed of more than 90 percent
pure cellulose. The end uses of dissolving pulp
include cellophane and rayon, cellulose esters
(acetates, nitrates, etc.), cellulose ethers
(carboxymethyl cellulose, etc.), graft and crosslinked
cellulose derivatives (Sjöström, 1981).
This research focuses on fast-growing biomass
utilization in producing dissolving pulp and
economic, high-quality feed-stocks for bio-energy
and bio-products. Pre-extraction conditions may
affect dissolved biomass components. Therefore,
the objective of this study was to pre-extract
dhaincha by acidic to alkaline medium prior to
kraft pulping in order to produce dissolving pulp.
The pre-extracted liquor and produced pulp were
characterized.
2. MATERIAL AND METHODS
Material
Dhaincha was collected from the Savar, Dhaka. It
was sun dried and leaves, dirt were removed. Then
it was cut to 2-3 cm in length by hand cutting
machine. The moisture content of dhaincha was
determined. After determination of the moisture
content of air dried dhaincha equivalent to 100 gm
oven dried (o.d.) was weighed separately in a
polyethylene bag for subsequent cooking
experiments.
The lignin (T211 om83) and pentosan (T223) of
these raw materials were analysed following Tappi
Test Methods. Holocellulose was determined by
treating extractive free wood meal with NaClO2
solution. The pH of the solution was maintained at
4 by adding CH3COOH-CH3COONa buffer and
-cellulose was determined by treating
holocellulose with 17.5 % NaOH.
Prehydrolysis
Dhaincha was pre-extracted by water, water with
0.2%H 2 SO 4 , water with 1% NaOH and water with
3% NaOH in an oil heated bomb digester. Preextraction
was carried out at 165 0 C for 60 min
time. The dhaincha to liquor ratio was 1: 6. The
time required to raise max temperature was 50
min. After completing pre-extraction, digester was
cooled by circulating cold water and the liquor
was drained for pH, solid content, lignin and
acetic acid determination. The percentage of
dissolved components were measured by
gravimetrically.
Lignin analysis
The dissolved lignin in the prehydrolysate was
measured based on the UV/Vis spectrometric
method at wavelength 205 nm (TAPPI UM 250)
(19).
Acetic acid
Acetic acid in the PHL was dehydrated by
anhydrous sodium sulphate. 1 µL was injected into
GC. Pure glacial acetic acid (GAA) was used as
reference standard. Analysis of GAA was carried
out on Gas Chromatograph model 14B, Shimadzu,
Japan loaded with software Class GC-10 (version-
20). The GC was equipped with Flame Ionization
Detector (FID) and Capillary Column,
FAMEWAX, dimension 15mX 0.25mm RESTEC.
Before injection the column was conditioned at
180oC for about 2h for attaining thermal stability
before use. The temperature of the column oven,
injection port and detector were 180 o C, 240 o C and
250 o C, respectively.
Solid contents
The total solid content in the PHL was determined
by drying at 105 o C till to constant weight.
Pulping
Pulping of pre-extracted dhaincha was carried out
in the same digester of pre-hydrolysis. Pulping
conditions of kraft were as follows:
- Active alkali was 18 % on oven-dry (o.d) raw
material as Na 2 O
- Sulphidity was 30%
- Cooking time was 120 min at maximum
temperature (170 o C). 90 min was required to raise
maximum temperature (170
o C) from room
temperature.
- Liquor to material ratio was 6.
After digestion, pulp was washed till free from
residual chemicals, and screened by flat vibratory
screener (Yasuda, Japan). The screened pulp yield,
total pulp yield and screened reject were
determined gravimetrically as percentage of o.d.
raw material. The kappa number (T 236 om-99) of
the resulting pulp was determined in accordance
with Tappi Test Methods.
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