Cogeneration And Pollution Control in Sugar mills: A review
India has been considered the original home of sugarcane and sugar. The art of making sugar was known during 4th and 6th century. Industrial centrifugal sugar production in India started in the mid of 1930s in sub tropical belt. The Indian sugar industry has achieved the unique position of being the largest producer of crystal sugar in the world through extensive network of 540 sugar factories located in India.
Next to textile, sugar industry provides direct employment to more than 3.6 lakh persons. The cultivation and transportation of sugarcane to the sugar mills provide a ...view middle of the document...
The industry provide employment to 0.5 million skilled and unskilled workers.
• Annual wage bill of industry US$3 billion
• Collection of central and state exchanges US$50 million/annum
• Alternative sweeteners 8-10 million/ annum
• Co-generation potential 5000 MW
• Current export of co-gen power (value) US$10 million/annum
• Employment including ancillary activities 2 million people
• Total cane price paid to the farmers US$3700million/annum
Sugar industry also produces a large variety of by-products which have established a large number of distilleries, organic chemical plants, and paper factories. Also most of the sugar mills in India generate their own power and thermal energy and also supply power to state electricity board.
With such extensive and diversified socio-economic activities, sugar industry holds a significant position in Indian economy.
2. Process of cane sugar production at a glance
Sugarcane processing is focused on production of cane sugar (sucrose). In this processing other by-products are also produced including bagasse, press mud, molasses, filter cakes etc. These by products are used for different purposes and also supplied to different industries.
Sugarcane is produced and harvested for 2 purposes- production of cane sugar and use as seed for subsequent planting.
When the sugarcane crop is ready for harvest, technicians from sugar mill perform some chemical analysis of the cane and find out its bricks purity. Bricks purity is the percentage of sucrose present in the cane. Depending upon the bricks purity technician advice the farmer to harvest the field with high bricks purity, so that they can get better returns for the cane and also from those canes a superior quality and quantity of sugar can be produced.
Hand cutting is the most common harvesting method but nowadays mechanical harvesters are also available. After cutting the cane is transported to the mills. At the entry of the mill the cane is weighed and the respective price of the cane is given to the farmers.
The cane carried directly from trucks and trolleys to the mill by the help of Triplers. Then the cane enters in to the Chopper which breaks the cane in to small pieces. Chopper has revolving knives and blades which on an average rotate at 36 rpm and at 50 HP power. Next the broken cane enters in to the Leveler for fine chopping. After leveler cane is in very fine form containing juice.
For the grinding or milling of crushed cane, multiple set of 3 roller mills are used. Mostly there are 5 set of roller mils. Conveyors transport the crushed cane from one mill to the next and at every mill juice is collected. At the last mill, water is applied to the crushed cane for better extraction of juice, and transferred from mill to mill towards the first mill, while the crushed cane travels from first to last mill. The crushed cane exiting out of the last mill is...