Before the sugars from the three different strikes can be handled further, the sugars must be separated from the respective massecuites
by centrifugation. Centrifugals are used for this purpose. They are large electrically driven machines with baskets or “tubs” enclosed
within. Some centrifugals are continuous, some are batch, and some are automatic batch machines.
The massecuite is introduced into the tub, which is lined with a very fine mesh screen. The baskets are then spun at high speeds. The
result is that the syrup is spun out through holes in the screen and the sugar crystals are trapped on the face of the screen. The sugar
crystals are then washed with hot water and/or steam. The syrup and crystal washings are collected and returned for further crystallization
(see crystallization section) and the sugar is removed from the screen either mechanically or centrifugally, dependant upon machine design.
High raw and low raw sugars are then conveyed to a “melter”, where they are dissolved in either thick juice or, in some cases thin juice,
and join the flow of standard liquor to the filters prior to being used as white pan feed stock.
Sugar crystals must be dried and cooled prior to storage
White sugars, after purging and washing in the centrifugals, are conveyed to the “granulator” for drying and cooling. The granulator is a
long rotating cylindrical device, which forces the sugar crystals to tumble through a continuous draft of hot (drying) or cold (cooling) air.
Following their passage through the granulator the sugar is first weighed (for accounting purposes) then conveyed, through a silo distribution
system, which allows the warehouse staff to choose into which of the five separate storage silos or combination of silos at SMBSC to send the
finished sugar. The sugar must remain in the sugar silos for a minimum of 48 hours prior to packaging or shipment in order to allow the residual
moisture in the sugar crystals to come to equilibrium with the humidity in the surrounding air, which prevents lumping problems later. This
process is called “curing”. There is a ventilation system in the silos that allows for warm air to be circulated in the silos, and the sugar
dust removed, during the filling of the silo. Air is also circulated in the silos as the sugar “cures” and it is emptied from the silo.
The amount of sugar produced from sugar beets ranges from 70 to 86 percent of the sugar that was in the beets when processed. The wide range
is due to the quantity and nature of the non-sugars that were also contained in the beets, along with factory processing techniques.
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