A sugar refinery is a factory which refines raw sugar.
Many cane sugar mills produce raw sugar, i.e. sugar with more colour and therefore more impurities than the white sugar which is normally consumed in households and used as an ingredient in soft drinks, cookies and so forth. Raw sugar is either processed into white sugar in local refinieries and sold to the local industry and consumers or it is exported and further processed in the country of destination.
While cane sugar does not strictly need refining, beet sugar is almost always refined to remove the strong, almost always unwanted, taste of beets from it.
The sugar refineries are often located in heavy sugar-consuming regions such as North America, Europe, and Japan. Since the 1990s many state-of-the art sugar refieries have been built in the MENA region, e.g. in Dubai, Saudi Arabia and Algeria. In the second stage, white sugar is produced that is more than 99 percent pure sucrose. In such refineries, raw sugar is further purified. Whereas many sugar mills only operate during a limited time of the year during the cane harvesting period, many sugar refineries work the whole year round.
The world´s largest sugar refinery company is American Sugar Refining with facilities in North America and Europe.
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The raw sugar is stored in large warehouses and then transported into the sugar refinery by means of transport belts. In the traditional refining process, the raw sugar is first mixed with heavy syrup and centrifuged to wash away the outer coating of the raw sugar crystals, which is less pure than the crystal interior. Many sugar refineries today buy high pol sugar and can do without the affination process.
The remaining sugar is then dissolved to make a syrup (about 70 percent by weight solids), which is clarified by the addition of phosphoric acid and calcium hydroxide that combine to precipitate calcium phosphate. The calcium phosphate particles entrap some impurities and absorb others, and then float to the top of the tank, where they are skimmed off.
After any remaining solids are filtered out, the clarified syrup is decolorized by filtration through a bed of activated carbon or, in more modern plants, ion-exchange resin.
The purified syrup is then concentrated to supersaturation and repeatedly crystallized under vacuum to produce white refined sugar. As in a sugar mill, the sugar crystals are separated from the mother liquor by centrifuging. To produce granulated sugar, in which the individual sugar grains do not clump together, sugar must be dried.its a good storage product last even for 7 years ..
Drying is accomplished first by drying the sugar in a hot rotary dryer, and then by blowing cool air through it for several days in so-called conditioning silos. The finished product is stored in large concrete or steel silos. It is shipped in bulk, big bags or 25 - 50 kg bags to industrial customers or packed in consumer-size packages to retailers.
The dried sugar must be handled with caution, as sugar dust explosions are possible. A sugar dust explosion which led to 13 fatalities was the 2008 Georgia sugar refinery explosion in Port Wentworth, GA.
As in many other industries factory automation has been promoted heavily in sugar refineries in recent decades. The production process is generally controlled by a central process control system, which directly controls most of the machines and components. Only for certain special machines such as the centrifuges in the sugar house decentralized PLCs are used for security reasons.[1]