This is used to transport cane to the milling tandem, and consists of chains and slats. Its width is normally equal to the mill size.Mill
A cane-crushing unit having normally consisting of three rollers in a heavy steel housing. Cane first passes between the top and front rollers, then between the top and back rollers, to extract the juice.Crushers
A cane crushing unit, preceding the first mill to crush the cane prior to extraction of juice, for the purpose of improving the quantity of juice extracted. Normally consists of two rollers.Shredder
This has the same purpose as the crusher, but a different principle. Consists of a drum, with a concentric shaft, on which hammers are mounted on arms.
A complete mill is complex, consisting of crusher (or shredder) and all mills, together with drives and reducing gears.
These are mounted on cane carriers prior to entrance to mills, for preventing entire cane stalks from entering the mills, straightening and precutting the cane, for the purpose of improving juice extraction and saving driving power at the same time.
These transport the milled cane (bagasse) from one mill to the next. BAGASSE CARRIER This carries the bagasse from the last mill to the boilers, and its excess to storage.
This produces electricity by means of non-condensing steam turbines, which drive generators.
A heat exchanger in which juice is heated by using steam as a medium, normally a multi-pass system. Juice flows through tubes, while steam passes along the outside of the tubes, in the cylindrical body.
It is a large vertical cylindrical tank, where juice is given time for decantation, to separate the clear juice from the turbid, which still contains the mud. Juice flow is continuous.
A device to separate the mud from the turbid juice; normally of the rotary vacuum type. , to let the juice pass and retain the mud on its surface.
A series of vessels, in which excess water from the juice is evaporated to form a more concentrated liquid, now called syrup. The vessels work in series under increasing vacuum conditions, to reduce the boiling temperature gradually as the concentration increases step-wise. This prevents overheating of juice and loss of sucrose. The vessels together form a triple-, quadruple- or quintuple-effect evaporator.
Similar to an evaporator vessel, a continuation of the evaporating process, but carried so far that crystallization occurs. Also boils under vacuum for reduced boiling temperature. The syrup is now transformed into massecuite , which is a mixture of crystals and molasses.
A strike receiver in which the charge from the vacuum pan is stored before going to the centrifugals. Its purpose is cooling, to increase grain size and reduce sucrose left in molasses.
A machine with a fast spinning drum and a screen, inside, through which the molasses can pass while the crystals are retained. Separation is based on the difference in specific gravity, amplified by centrifugal force.
A long drum-like rotating cylinder, where sugar is brought in contact with heated air, to reduce its moisture content.
Same as a dryer, but air is dry and cooled to reduce temperature of sugar, heated by the dryer. This is to prevent caking during storage. The combination of dryer an
Sugar has to be dried and cooled to precise levels to enhance its storage life. This is done in the sugar driers. Evaporation of excess water from the surface of the crystals results in the desired cooling of the sugar. In the generally wet conditions we use large air-conditioning units to provide the cool dry air to the sugar driers. The dried and cool sugar is now ready for shipment.
The typical composition of Sugarcane is as follows:
15% dissolved matter (13% sucrose; 2% are other sugars-mainly glucose and fructose)
Though the basic raw material is sugar cane, for processing sugar cane into sugar, other chemicals are required, such as lime, sulphur, caustic soda, washing soda, other consumable like oils and greases, lubricants, gunny bags, fire wood etc.
Man - Power Requirement
The manpower requirement will be of two categories
Depending upon the capacity of the plant suitable land area is required for the Plant & Machinery, Godowns, Molasses tanks, Storage, Office Building, and Cane Yard etc. The land should have good approach road for transport of cane, Sugar, Molasses etc., & should have water facility.
Building, Plant & Machinery
All the stations of Plant, Milling, Boilers, Power House, Boiling House, Centrifugal System, Sugar House etc., shall have the building.
A basic cane mill consists of three grooved rollers. Prepared cane is squeezed between the rollers, thus forcing the juice out of the fibre. The bagasse left in the last set of roller will be used for fuel to power the boilers to produce steam and generate electricity for use in subsequent sugar production process.
Juice from a milling tandem contains a large amount of cane fibre, dirt and unwarranted particles that falls out with the juice between the rollers of the mills. To make it lucid and clear juice the juice is poured over a wire-mesh screen. And then the juice is heated and lime is added to neutralise the natural acidity. It is then placed in a Clarifier which produces a clear juice that is light in colour and free of suspended matter.
The clarified juice is then put through multiple evaporators to extract up to 60–65% of water from it, leaving the juice becoming concentrated or syrup with 60–65 brix. Multiple effect evaporation is the system where juice is boiled in series in several vessels, with steam fed to vessel 1 only. Vapour from vessel 1 boils the juice in vessel 2, vapour from 2 boils the juice in 3, and so on until vapour from the final vessel goes to waste.
Sugar boiling is conducted under “vacuum pan” process in order to lower operating temperatures, but some small scale manufacturer of sugar “open pan” processes. The syrup produced by the evaporators is concentrated further in pans. As the concentration rises the dissolved sugar crystallises and the work of the pans is to grow sugar crystals in several steps to maximise the amount of sucrose recovered in raw sugar.
When the massecuite is discharged from the pans it is retained in crystallisers, where the sugar crystals continue to grow through cooling rather than boiling. The crystallisers are U-shaped vessels where massecuite is slowly rotated and allowed to cool. This technique is often referred to as “crystallisation in motion”. Rotation promotes even cooling of the massecuit, which helps to achieve uniform crystal growth. Uniform crystal growth can also be encouraged by placing granulated massecuit from a previous batch into the crystalliser with the fresh massecuit. This process is known as “seeding”.
A centrifugal is a machine that separates crystals from molasses. Centrifugation involves spinning massecuite in a perforated basket; centrifugal force acts on the molasses, forcing it through the perforations while the sugar remains on the basket wall. Water and steam may then be sprayed onto the crystals to wash off the remaining molasses.
In a drier, the moisture is driven off from the surface of the liquor layer covering the crystal by passing heated air around the sugar crystals. The product from the process described so far is a raw sugar (Brown sugar) that can be used as is, or sent to a refinery to be converted to a white (refined) sugar.
Bagasse is the final residual of the cane after it has underwent crushing/milling process. Nowadays, bagasse is used as fuel in generating electricity and steam the sugar production process. Furthermore, bagasse can be used as raw material for producing paper, insulating board, and hardboard, as well as furfural, a chemical intermediate for the synthesis of furan and tetrahydrofuran. The end product derived from sugar refining is blackstrap molasses.
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