Lynne Wong's PhD thesis

In this section, the previous examination of the effects of cane quality on cane processing
from 1960 to 1996 carried out by Wong Sak Hoi and Autrey (1997), has been updated to
2004. Parameters such as mill extraction, sucrose lost in filter cake % sucrose in cane,
Clerget purity of molasses and mass of molasses at 85° Brix % cane and sugar quality were
examined.
1.5.3.1 Mill extraction
With increased trash in cane, extraction is adversely affected. There is an increase in the
energy requirement at knives and shredders, a decrease in crushing rate, imbibition
efficiency and mill extraction, with increased occurrences of roll slip. The "sponge" effect
of trash will also increase the sucrose lost in bagasse.
As shown in Fig 1.10, the changes in mill extraction and sucrose lost in bagasse % cane are
quite complex, they have been broadly divided into three periods by Wong Sak Hoi and
Autrey (1997):
Mill extraction
98
Mill extraction
97
96
95
94
93
Sucrose lost in bagasse % sucrose in cane
92
1960 1965 1970 1975 1980 1985 1990 1995 2000
6.5
5.5
4.5
3.5
2.5
Sucrose lost in bagasse % sucrose in cane
Figure 1.10. Changes in mill extraction and sucrose lost in bagasse
% sucrose in cane from 1960-2004.
• From 1960 to 1976, when mill extraction was improving slightly. This was the period
when mills were modernized, cane preparation was improved and arcing of mill rollers
was started.
23