Following Third Saturation, the thin juice flows to a surge vessel called the evaporator supply tank. From this tank the thin juice is
pumped through a series of multiple effect evaporators. These evaporators are designed so that the vapor given off by the boiling juice
in the first or previous evaporator is the heat source for the next evaporator. The source of heat for the first evaporator in the series
is steam; generally exhaust steam from the factory’s turbine generators and also here at SMBSC vapor from the pulp drying operation. The
thin juice enters the evaporator set at about 12 to 18 percent solids and leaves between 61 and 72 percent solids. The juice at this stage
is called thick juice. Its exit percent solids depends upon the evaporator and sugar end configuration, whereas the inlet concentration
depends almost entirely upon the sucrose content of the beets processed.
Evaporators remove water from the Juice
The percent solids concentration in the juice desired for the next stage in the separation process, crystallization, are 72 percent or higher.
This may be accomplished in any number of ways. The most common approach taken is to dissolve re-melt sugars in the thick juice melter, and
pass them through another evaporator, called a concentrator. The juice, or more correctly at this point, syrup, is called standard liquor. It
was for many years called “blow up” or “blow up thick”; terms nearly obsolete today.
At this factory the capacity for making thick juice is greater than the capacity to crystallize it. Therefore, we take a portion of the thick
juice and/or a portion of the standard liquor and store it in large tanks for processing when the beet slice has ended for the year or been
interrupted by weather conditions. We can store the thick juice here at SMBSC, which will later produce nearly 300,000,000 pounds of refined
beet sugar. When the sugar content of beets is particularly high, or the non-sugar content of the beet is too high to promote rapid
crystallization, more juice is placed in storage.
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