sugar manufacture dr vijaya shastry

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Page 1: Sugar manufacture dr vijaya shastry

A Presentation

Page 2: Sugar manufacture dr vijaya shastry

Introduction.

History of Sugar.

Sugar Manufacturing Process.

Sugar Industry

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History of Sugar• It is thought that cane sugar was first used by man

in Polynesia from where it spread to India. • In 510 BC the Emperor Darius of what was then

Persia invaded India where he found "the reed which gives honey without bees“.

• It was the major expansion of the Arab peoples in the seventh century AD that led to a breaking of the secret. When they invaded Persia in 642 AD they found sugar cane being grown and learnt how sugar was made.

• Sugar was only discovered by western Europeans as a result of the Crusades in the 11th Century AD.

• In the 15th century AD, European sugar was refined in Venice.

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What is Sugar?What we call sugar, the chemist knows as

'sucrose', in the grouping called carbohydrates.

The simplest of the sugars is glucose, C6H12O6

Sucrose, C12H22O11, is a condensation molecule

made up of two glucose molecules [less a water

molecule to make the chemistry work].

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How Sugar is formulated? The process whereby plants make sugars is photosynthesis. The plant

takes in carbon dioxide from the air though pores in its leaves and

absorbs water through its roots. These are combined to make sugar

using energy from the sun and with the help of a substance called

chlorophyll. Chlorophyll is green which allows it to absorb the sun's

energy more readily and which, of course, gives the plants' leaves their

green color. The reaction of photosynthesis can be written as the

following chemical equation when sucrose is being made:

12 CO2 + 11 H2 O = C12 H22 O11 + 12 O2

carbon dioxide + water = sucrose + oxygen

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StatisticsSugar is produced in 121 Countries. Global production now exceeds 120 Million

tons a year. Per Capita annual consumption is 30 – 46 kg.Approximately 70% is produced from

sugar cane.The remaining 30% is produced from

sugar beet.

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By-Product Of Sugar CaneBagasse:It is produced in the mill house in a quantity

of about 30% of the crushed cane.The bagasse contains 50% moisture

It is used as a fuel for boilers (processing stage).Bagasse is also used for chip-board and paper manufacture.

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Molasses:

Molasses is a common ingredient in baking, often used in baked goods such as ginger bread cookies.

80% of total available molasses is exported

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Ethanol:The sugar sector has the capacity to

produce over 2.5 million metric tons (MMT) of molasses available for processing into ethanol.

sugar industry produces more than half a million tons of ethanol per annum from cane molasses, over 50 per cent of which is exported at an average price of about $500/MT. Main destinations include: Europe, Far Eastern (Korea, Japan, Taiwan and the Philippines) and Middle East (Dubai and Saudi Arabia).

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History of Sugar• It is thought that cane sugar was first used by man

in Polynesia from where it spread to India. • In 510 BC the Emperor Darius of what was then

Persia invaded India where he found "the reed which gives honey without bees“.

• It was the major expansion of the Arab peoples in the seventh century AD that led to a breaking of the secret. When they invaded Persia in 642 AD they found sugar cane being grown and learnt how sugar was made.

• Sugar was only discovered by western Europeans as a result of the Crusades in the 11th Century AD.

• In the 15th century AD, European sugar was refined in Venice.

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Sugar Manufacturing Process1. Growing & Harvesting the

Cane2. Cane preparation for Milling3. Milling4. Clarification5. Evaporation6. Crystallization7. Centrifugation8. Drying9. Refining

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Manufacturing Process and Technology

Sugar (sucrose) is a carbohydrate that occurs naturally in every fruit and vegetable. It is a major product of photosynthesis, the process by which plants transform the sun's energy into food. Sugar occurs in greatest quantities in sugarcane and sugar beets from which it is separated for commercial use. The natural sugar stored in the cane stalk or beet root is separated from rest of the plant material through a process known as refining.

  For sugarcane, the process of refining is carried out in following steps

Pressing of sugarcane to extract the juice. Boiling the juice until it begins to thicken and sugar begins to crystallize. Spinning the crystals in a centrifuge to remove the syrup, producing raw

sugar. Shipping the raw sugar to a refinery where it is washed and filtered to

remove remaining non-sugar ingredients and color. Crystallizing, drying and packaging the refined sugar

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Beet sugar processing is similar, but it is done in one continuous process without the raw sugar stage. The sugar beets are washed, sliced and soaked in hot water to separate the sugar -containing juice from the beet fiber. The sugar-laden juice is then purified, filtered, concentrated and dried in a series of steps similar to cane sugar processing.

For the sugar industry, capacity utilization is conceptually different from that applicable to industries in general. It depends on three crucial factors the actual number of ton of sugarcane crushed in a day, the recovery rate which generally depends on the quality of the cane and actual length of the crushing season.

  Since cane is not transported to any great extent, the quality of the cane that a factory receives depends on its location and is outside its control. The length of the crushing season also depends upon location with the maximum being in south India.

Sugarcane in India is used to make either sugar, khandsari or gur. However, sugar products produced worldwide are divided into four basic categories : granulated, brown, liquid sugar and invert sugar.

Granulated : Granulated sugar is the pure crystalline sucrose. It can be classified into seven types of sugar based on the crystal size. Most of these are used only by food processors and professional bakers. Each crystal size provides unique functional characteristics that make the sugar appropriate for the food processor's special need.

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Sugar Beet

Sugar beet is a temperate climate biennial root crop. It produces sugar during the first year of growth in order to see it over the winter and then flowers and seeds in the second year. It is therefore sown in spring and harvested in the first autumn/early winter. As for sugar cane, there are many cultivars available to the beet farmer. The beet stores the sucrose in the bulbous root which bears a strong resemblance to a fat parsnip. A typical sugar content for mature beets is 17% by weight but the value depends on the variety and it does vary from year to year and location to location. This is substantially more than the sucrose content of mature cane but the yields of beet per hectare are much lower than for cane so that the expected sugar production is only about 7 tons per hectare.

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The processes in this industry are

Cane Shredding The cane is broken/cut into small pieces to enable easier movement through the

milling machine. Milling The shredded cane is passed through rollers which crush them to extract cane juice.

[Similar to the cane juice extracted by the vendors who sell you sugar cane juice.] Heating and Adding lime The extracted juice is then heated to make it a concentrate and lime is added to the

heated juice. Clarification Muddy substance is removed from the concentrate through this process Evaporation Water is removed from the juice by evaporation. Crystallisation and Separation Sugar crystals are grown from the dry juice concentrate in this process. Spinning Molasses are separated from sugar using Centrifugals in this process. Drying Sugar is obtained by drying the wet raw sugar obtained in the spinning process.

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How is sugar processed?

The initial stage involves sampling, weighing and washing the sugarcane. From there the material passes to can crushers and then into the mill. The bagasse, which results from the milling, is used in the boilers for steam production that is used to power the process. The surplus bagasse from this stage is used in industry

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Harvesting

Sugar cane is harvested by chopping down the stems but leaving the roots so that it re-grows in time for the next crop. Harvest times tend to be during the dry season and the length of the harvest ranges from as little as 2 ½ months up to 11 months.

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Page 23: Sugar manufacture dr vijaya shastry

Extraction

The first stage of processing is the extraction of the cane juice. In many factories the cane is crushed in a series of large roller mills: similar to a mangle [wringer] which was used to squeeze the water out of clean washing a century ago. The sweet juice comes gushing out and the cane fibre is carried away for use in the boilers. In other factories a diffuser is used as is described for beet sugar manufacture. Either way the juice is pretty dirty: the soil from the fields, some small fibres and the green extracts from the plant are all mixed in with the sugar.

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Clarification

The extracted cane juice is pH tested and adjusted with lime before it is heated and sent to large clarifying tanks. These tanksallow for the settling of solids to the bottom leaving only clear juice to continue through the process.

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Page 27: Sugar manufacture dr vijaya shastry

Evaporation

The factory can clean up the juice quite easily with slaked lime (a relative of chalk) which settles out a lot of the dirt so that it can be sent back to the fields. Once this is done, the juice is thickened up into a syrup by boiling off the water using steam in a process called evaporation. Sometimes the syrup is cleaned up again but more often it just goes on to the crystal-making step without any more cleaning. The evaporation is undertaken in order to improve the energy efficiency of the factory.

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Boiling

The syrup is placed into a very large pan for boiling. In the pan even more water is boiled off until conditions are right for sugar crystals to grow.

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Crystallisation

The heated syrup begins to crystallize and separates into sugar crystals and molasses called "massecuite." The crystallizers cool the mixture of sugar crystals and molasses which causes the crystals to grow in size.You may have done something like this at school but probably not with sugar because it is difficult to get the crystals to grow well. In the factory the workers usually have to throw in some sugar dust to initiate crystal formation.

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Centrifugation

To remove the sugar crystals from the molasses, high-speed rotating centrifugals spin off the molasses leaving only the raw sugar crystals on the centrifugal screens. The remaining product is blackstrap molasses which is then stored in tanks and later sold as cattle feed. After all of the commercially recoverable raw sugar is produced it is transferred into huge warehouses for storage until It is ready to be transported to refineries.

Sugar processing is a highly specialized, computer-controlled, technical process that requires a combination of sensitive machinery and experienced individuals to succeed. Approximately one ton of sugarcane is required to produce 220 pounds of raw sugar. We at Sugar Cane Growers Cooperative of Florida are proud of our facilities and the people who run them.

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Storage

The final raw sugar forms a sticky brown mountain in the store and looks rather like the soft brown sugar found in domestic kitchens. It could be used like that but usually it gets dirty in storage and has a distinctive taste which most people don't want. That is why it is refined when it gets to the country where it will be used. Additionally, because one cannot get all the sugar out of the juice, there is a sweet by-product made: molasses. This is usually turned into a cattle food or is sent to a distillery where alcohol is made.

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Power

So what happened to all that fibre from crushing the sugar cane? It is called "bagasse" in the industry. The factory needs electricity and steam to run, both of which are generated using this fibre.

The bagasse is burnt in large furnaces where a lot of heat is given out which can be used in turn to boil water and make high pressure steam. The steam is then used to drive a turbine in order to make electricity and create low pressure steam for the sugar making process. This is the same process that makes most of our electricity but there are several important differences.

When a large power station produces electricity it burns a fossil fuel [once used, a fuel that cannot be replaced] which contaminates the atmosphere and the station has to dump a lot of low grade heat. All this contributes to global warming. In the cane sugar factory the bagasse fuel is renewable and the gases it produces, essentially CO2, are more than used up by the new cane growing. Add to that the factory use of low grade heat [a system called co-generation] and one can see that a well run cane sugar estate is environmentally friendly.

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Uses of Sugar

Sugar is used for many purposes in the food industry. It is vital in maintaining the safety and availability of our food.

Ice cream is made thicker and smoother with sugar. More than 20% of ice cream is sugar.

Sugar helps cakes to be moist and soft, and to stay fresh longer. Soft drinks and fruit juice are often 10% or 12% sugar. As well as adding

flavour, the sugar makes the drinks heavier and more pleasant to drink. The sugar in jams helps them to keep for a longer time, by stopping

mould and germs from growing. Natural sugar in canned fruit also acts as a preservative in the same way. Condensed milk relies on up to 55% sugar content. Cane sugar is used in making many lollies. Sugar is used to bring out the flavours of other foods such as preserved

meats, tomato sauce and canned soup. Custard is made smooth and creamy as well as sweet by sugar. Many medicines have sugar added to hide their bitter taste. Some cough

syrups have sugar to make them more soothing

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THANKSEmail [email protected] Phone9819794779

Asst Prof, Physical Chemistry, RJ CollegeGhatkopar,Mumbai, India