Draw the Block Diagram (BD) for the following Manufacturing process:
Sugar manufacturing process:
Sugar production involves a series of physical processes including juice extraction, clarification, evaporation, crystallization, and drying. In addition to the main process units, a typical sugar mill has a cogeneration system where process steam and power are generated, and a cooling tower for cooling process warm water.
Sugarcane from the farm is first cut and shredded using knives and shredders to break the hard structure and rupture sucrose cell for easy juice extraction. Juice extraction is usually done either by compressing shredded cane in roller mills to squeeze out the juice (milling method), or by the diffusion method through a countercurrent hot water leaching process at a suitable temperature
In the clarification unit, the draft juice is first heated and limed to enhance precipitation and separation of some non-sucrose impurities and fine bagasse from the juice. Liming also provides a nearly neutral pH, suitable for clarification and restricting sucrose inversion in subsequent evaporation.
Clarified juice contains about 85% (by weight) of water, most of which is removed by boiling, to concentrate the sugar. The evaporation unit, mainly comprises a heat exchanger to preheat clear juice to about 110 C.
The crystallization process starts by boiling syrup (concentrated juice) in conventional batch or continuous vacuum pans while adding a slurry of fine sugar crystals to seed crystals formation. The hot mixture of crystals and the mother liquor (molasses), called massecuite is then discharged from the vacuum pan into cooling crystallizers for further crystallization. Subsequently, the sugar crystals are filtered and washed out of the liquor in centrifuges.
Drying is the last process in raw sugar production, traditionally done in a rotary drum dryer tilted at an angle of about 5 to the horizontal to allow continuous flow of the sugar through the drier. Hot air is fed into the dryer counter current to the sugar flow and by continuously lifting and dropping the sugar crystals, they are cooled and dried.