PREPERATION ON SUGER FROM SUGER CANE:
The preparation
of sugar from sugar cane composed of following steps :
. Harvesting
and delivery
. Juice extraction
. Clarification
. Concentration
. Crystallization
. Crystal
separation and drying
HARVESTING
AND DELIVERY OF SUGAR CANE:
Sugarcane is generally harvested in the cooler month of the year ,
although it is harvested year-round in all over the Sindh . as much of
two-third of the world cane crop is harvested by hands but in same countries
this process is also done by machine . Harvested cane is transport to the
factory by many means and vehicles , such as oxcarts, trucks, rail cars, or
barges
JUICE
EXTRACTION:
After weighing, sugarcane is loaded
by hand or crane onto a moving table. The table carries into one or two seats
of revolving knifes, which chop the cane into chips in order to expose the tissue
and open the cell structure, thus readying the material for efficient extraction
of the juice
CLASSIFICATION
OF EXTRACTED JUICE:
Mixed juice from
the extraction mills or diffuser is purified by addition of heat, lime, and
flocculation aids. The lime is a suspension of calcium hydroxide, often in a
sucrose solution, which form of calcium saccharate compound. The heat and lime
kill enzymes solution, which forms a calcium saccharate compound. The heat and
lime kill enzymes in the juice and increase pH from a neutral acid level of 5.0-6.5
to a neutral Ph . Control of pH important throughout sugar manufacture .
CONCENTRATION
OF CLARIFIED JUICE :
Steam is
used to heat the first of a series of evaporation. The juice is boiled and
drawn to the next evaporation , which is heated by vapour from the first
evaporation . The process continue through the series until the clarified
juice, which consist of 10-15 percent sucrose, is concentrated to evaporator
syrup, consisting of 55-59 percent sucrose and 60-65 percent by weight total
solids
CRYSTALLIZATION
ON CONCENTRATED JUICE:
Syrup from the evaporator is sent to vacuum
pans, where it is further evaporated under vacuum, to super saturation . fine
seed crystals are added , and the sager ‘’mother liquor” yield a solid precipitate
of about 50 percent by weight crystalline sugar. Crystallization is a serial
process and named as A molasses, B molasses, C molasses and final molasses. Which
is 25% sucrose and 20%(glucose and fructose).
CRYSTAL
SEPERATION AND DRYING:
Crystal are separated in basket-type
centrifuge machine. The machine continuously break the crystals through continuous
centrifuge process and a fine jet of water is sprayed on the sugar pressed
against the wall of the centrifugal basket, reducing the syrup coating on each
crystal. In modern process is quite extensive in an effort to produce
high-purity raw sugar
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