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

smadho@smri.org bbarker@smri.org rramaru@smri.org

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