Curing of C-massecuites
• The SMRI-NIRS predictions can also be used to determine target
purity differences (TPD) for each C-centrifugal.
• Figure 2 below shows that the TPDs can be used to replace
molasses purity rise determinations. Advantages of this include:
Frequent analyses to identify losses timeously (TPD predictions
can be done as often as twice per shift to show centrifugal losses,
whereas purity rise determinations are often only done once daily
and on selected centrifugals). Torn screens and poor operations
(e.g. overwashing) can be identified rapidly.
Molasses purity rise determinations required a Nutsch sample; this
isn’t needed for NIRS TPD predictions.
Figure 2. Results showing that SMRI-NIRS TPD predictions for each
centrifugal can be used to replace C-molasses purity rises. The
results also show the high TPD and purity rise for centrifugal 4 was
as a result of low molasses brix (through overwashing).
Profile of reducing sugars
Figure 3. Use of SMRI-NIRS predictions to show fructose/glucose
ratios across the boiling house – useful to identify areas of reducing
sugar formation/destruction, Maillard-type reactions, etc.
MADHO S, BARKER B AND RAMARU R
Sugar Milling Research Institute NPC, c/o University of KwaZulu-Natal, Durban, 4041, South Africa
[email protected] [email protected] [email protected]
Boiling House Control
© SMRI
2015
high UDL high TPD
low BHR low OR low VR
small magma crystals increased centrifugal purity rises
large purity drops across evaporators
high molasses factor
high remelt purity low exhaustions high reducing sugar ratios high molasses purity
increased m3 massecuite per tonne MJ brix
Summary All of the South African sugar mill laboratories have access to Near Infrared Spectroscopy (NIRS) instruments with process stream
calibrations supplied by the Sugar Milling Research Institute NPC (SMRI). The calibrations include fructose, glucose and sucrose (FGS), and
also pol and brix predictions for mixed juice, clear juice, syrup and all the various grades of molasses and massecuites. Further to this, dry
solids can be predicted on C-molasses, and conductivity ash on mixed juice and C-molasses. The rapid and reliable predictions by NIRS
can be used by factories to improve recoveries and rapid reporting of factory performance figures. This poster elucidates some approaches
on how to achieve this.
Determining Undetermined Losses
Evaporator inversion losses
• Conventional SMRI method of evaporator inversion loss
determinations:
Disadvantages: Long lead times (± 2 weeks, excludes results interpretation and
report writing) and once-off tests usually done.
• New SMRI-NIRS method of evaporator inversion loss
determinations:
Result: Many tests under different factory conditions can be performed by mill
staff, with conclusions drawn using SMRI inversion loss toolkit, all within a day.
Figure 1. Sucrose lost across 1st effect evaporators in a
South African sugar factory
• The method to determine inversion losses across evaporator
stations using the SMRI-NIRS predictions has been developed and
demonstrated to several mills in 2014 and 2015.
• A spreadsheet toolkit has also been developed to input the NIRS
analytical results for any evaporator station configuration and
calculate the estimated sucrose losses.
• The devised method and a trial version of the toolkit has already
been used at three mills, using different processing conditions,
and has determined possible losses in excess of R70,000 daily
under certain conditions.
• A standard operating procedure (SOP) and the final version of the
spreadsheet toolkit will be issued to all SMRI member mills in 2015.
85.3% brix
83.7% brix
84.1% brix
82.4% brix
87.7% brix
PRACTICAL USE OF NIRS FOR FACTORY
PROCESS CONTROL
True purity rise (%)
NIR
S TP
D
Read on
Sample time (minutes)
Sucr
ose
lost
(%
)
Fru
cto
se/G
luco
se
Also ask about… • Sucrose-based factory performance calculations
• Massecuite and seed target purity predictions
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