Lynne Wong's PhD thesis

from Figure 2.9 that the change in fibre % cane is 0.572, 0.132 and –0.001 due to one unit
of dry leaf, green leaf and cane tops respectively; except in the case of dry leaf addition to
44 weeks old cane.
3.5.3.5 Fibre % cane results by direct cane analysis
It has been pointed out that the fibre % cane calculated from the mass of the extracted
fibres appear to be on the low side. This is confirmed by the fibre % cane results obtained
by direct cane analysis (Anon., 1991) performed on parallel samples and shown in Table
3.18. For the samples aged 52 weeks, the calculated fibre % cane values are 2 – 4 units
lower than the analytical results, whereas for the samples aged 44 and 36 weeks, only
about one unit (except the M 1557/60 aged 44 weeks) difference was found.
3.5.4 Characterisation of sugar cane component parts
The components separated from the sugar cane plant were characterised by measuring their
gross calorific values and by investigating their structure and morphology by means of
infra-red spectroscopy and scanning electron microscopy, respectively.
3.5.4.1 Gross calorific value
Snow (1974) also mentioned that with a high pith content in cane, extensive problems
would be encountered by the high residual moisture content of bagasse due to the fact that
pith can easily pick up atmospheric moisture and absorb more water during cane
processing than fibre, entailing additional expenses through increased consumption of
auxiliary fuel oil to burn the bagasse.
The results of the determination of the calorific value of the various cane components are
shown in Table 3.19; it is evident that while extracted rind has the highest GCV of 19 443
kJ kg -1 , followed by stalk fibre (19 041 kJ kg -1 ) and dry leaf (18 268 kJ kg -1 ); stalk pith has
the lowest GCV (17 512 kJ kg -1 ) of about 8% less than stalk fibre. The stalk fibres of
R 579 and R 570 appear to have higher GCV than those of the other two cane varieties.
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