Shakrganj mills internship report by Imitaz

Imtiaz AliNajeeb ur Rehman

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U.E.T Lahore

Shakarganj Mills Privatelimited


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Letter of Transmittal

Mr. Imtiaz Ali,

Mr. Najeeb ur Rehman,

University of Engineering and Technology

Lahore.

HOD production House,

Shakarganj Mills Jhang

Respected Sir,

Here is the report on Production departmentOf Shakarganj sugar mill you asked to submit on 30th July2012.As you will see in the report, we have discussed about theunderstanding of the flow of Juice, some, how juice is extractedfrom sugarcane, steam production and power production plant.

We have put our best in this report to make iteffective and understandable. We hope our report will beaccording to your demands from us. If you need any assistance ininterpreting this report please contact us.

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Yours sincerely,

Signature:Dated: 30th July 2012

Executive Summary:

First of all the cane isgenerally weighted on large platform scale in the transportunit. Then the sugarcane is carried to the mill house for theextraction of juice from it. After extraction juice is sent tothe heaters and clarifiers for purification. When largerimpurities like mud are removed then juice is carried to theevaporators where water is removed and Syrup is transported tothe Pan station where crystallization occurs.

Then for further clarification of the liquor it issent to the Telo station. At the end clarified liquor is Refined

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at the Refined Pan station. Refined sugar is dried and packedfor commercial use.

Acknowledgements:

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“My gratitude is for the well-esteemedorganization Shakarganj for giving me an opportunity to enhancemy practical knowledge in the field of Sugar Manufacturing.

This internship report could not have beencompleted without the help of capable and concerned individuals.First and foremost, I would like to thank Engr. Shahzad andEngr. Zeshan, of Production Department of Shakarganj under thekind Supervision of whom I have completed this report.

Special thanks to Mr. Ammar Hanif and Engr. Noumanfor helping us in every sort of quarries during the period ofour internship.

I would also like to thank the Engineers,Supervisors and In-charges of Boiler House, Power House, Mill House andProcess House who very generously let me enhance my knowledge andalso made me familiar with the professional attitude, manner andskills as well.”

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ContentsIntroduction:.....................................................1Cane Unloaders....................................................1Mill house tandem No.1.........................................2Dumping Carrier.....................................................2Main Carrier........................................................2

Levelers............................................................3Pusher Drum.........................................................3

Fabirizer...........................................................3Magnetic Iron Separator.............................................4

Mill house Tandem No. 2........................................4Cutters.............................................................4Cane Shredder.......................................................5

Rotary Mills.........................................................5Mill House Output...................................................6

Boiler House......................................................7Types of Boilers....................................................7Boiler Fans.........................................................8

ID Fan (Induced Draught Fan):.....................................8FD Fan (Forced Draught Fan):......................................8

SD Fan (Secondary Fan):...........................................9Super heater........................................................9

Air Pre-heater......................................................9Key Factors For Boiler Efficiency Calculations......................9

Boiler Water treatment Plant.................................10

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Why we need Water Treatment…?......................................10Reverse Osmosis Plant.............................................10

Demineralization plant:............................................11Deaerator..........................................................11

Power House....................................................12Back Pressure Turbine..............................................12

Condensed Turbines.................................................12

Production House................................................13Primary Heaters....................................................13

Defication tanks...................................................14Lime Dozer.........................................................14

Retention Tanks....................................................14Defecation Tanks:..................................................15

Secondary heaters..................................................15Flash Tank.........................................................15

Clarifiers.........................................................16Mud Level in Clarifiers............................................16

Mud Boot...........................................................16BD (begasse dust) Mixer............................................17

Vacuum Filter......................................................17Preheaters:........................................................17

Evaporators......................................................18Syrup storage tank.................................................20

Raw crystallization............................................20Sugar Refining...................................................23Reaction tank......................................................25

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Telo Clarifiers....................................................25Pressure filters...................................................26

Deep Bed Filters...................................................27

Refine crystallization and centrifugation................28Packaging and storing of refined granulated sugar.....28

Introduction :

Steps involved in sugar manufacturing:

Cane Preparation Milling/Juice Extraction Juice Purification Evaporation Raw Sugar Crystallization Liquor Clarification Refinery Sugar Crystallization Drying and Packing

Cane Weighing:

Cane is Brought from cane yard to SugarFactories on the Trucks and Trawlers .Cane weighing is takeplace with the help of Three Weigh Bridges. These Weigh Bridgesare Avery England Design .02 Weigh Bridges are for Gross Weightand 01 Weigh Bridges is for Tare Weight..Capacity of the WeighBridges is 50 Tons.Mill House:

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After weighing of the cane, sugarcane is movedto the mill station for the extraction of the juice. There aretwo mills working for the extraction of the juice named as:

Mill house Tandem No. 1 Mill house Tandem No. 2

Cane Unloaders:

There are two types of Unloaders

Mechanical type cane unloader Hydraulic type cane unloader

The function of cane unloader is to pick the cane from thetractor and put in to the carrier. Cane Unloading is done withthe help of Electric Hoists. Three Electric Hoist are attachedto Mill Tandem .The Function of these Electric Hoists is to Liftthe Cane loaded Truck and throw it to Dumping Carrier. It canlift 40-50 ton at a time. Lifting Speed 13-20 ft/min

Lifting Height 20 m

Mill house tandem No.1:

Dumping Carrier:

There are three dumping carrier in eachmill tandom. In Which sliding plates are attached which carrythe cane to the Main Carrier. Idler Pulleys are used to supportthe chain on which sliding plates move. These idler pulleys arecoated with some material so that to stop wear and friction. V-

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Belt drive used to transmit power from motor driven shaft togear system and from there with the chain sprocket mechanism itdrives the Dumping.

Dumping Carrier Length42 ft

Dumping Carrier Angle18deg

When high torque load is to be transmitted. We use chainsprocket mechanism. By the Formula of power as torque is veryhigh and speed is low then slippage takes place. So belt couldnot be used there and chain sprocket mechanism is the betterchoice.

Main Carrier:

After passing out through the Dumpingcane carriers, sugarcane moves into the Main cane carrier. MillTandem no. 1 has main cane carriers of different lengths. Maincane carrier in Tandem no. 2 has three cutters while maincarriers of Tandom no. 1 have two levelers on it to move thecane in an organized way.

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Levelers:

As the name implies it function is toprovide evenly feed to cutters. Mill Tandem No. 1 has twoLevelers. These are rotated by the motors. As they rotate theylevel the sugarcane passing through the levelers. Leveling thecane not only increases the capacity of the Tandem but also itmakes the juice extraction easy.

Leveler 1 No. Ofarms 26 Leveler 2 No ofarms 24

Pusher Drum:

The function of the pusher drum is to push thecompact sugar cane to the Fabiriser.

Dia of Drum2250 mm

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Length of the Drum 7200mm

Fabirizer:

Fabirizer does the same function in Tandom #1 asShredder in Tandom #2.In Fabirizer it takes input feed from thetop and pushes it to the bottom. It has anvil plate on the top.Then it has feed rake bar and rake bar under carrier.It is Turbine Driven.

Magnetic Iron Separator:

Iron or other harmful metals mayattach to the sugar during harvesting or transporting. Theseparticles must be removed otherwise they may harm the mills. Thepurpose of magnetic iron separator is to separate the ironparticles attached to the sugarcane.

Power17.7 kW

Mill house Tandem No. 2 :

Cutters: The purpose of cutters here is to cut the canein small pieces so that they are easily shredded and juice cane

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be extracted more efficiently. Ther are Three cutters for MillHouse Tandem No. 2.

Cutter #01 No. ofknives 70 Cutter # 02 No. ofknives 70 Cutter # 03 No. ofknives 52

Cane Shredder:

The main function of the shredder isto rapture the structure in order to open the cells of the

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cane .It is driven by Backpressure Impulse Turbine. ThisShredder is covered by anvil plate .It is below the Shredder. Ithas very low spacing in mm with hammers . Shredder has Stainlesssteel hammers with beadings. Shredder gets feed from below andtakes it above .that is why its anvil plate is below.

Rotary Mills:

This is the area where juice is extracted fromthe cane and is separated from the Baggasse.Numbers of mills forMill House Tendem No.1 and Tandem No. 2 is different. RotaryMills are run by th turbines which provide sufficient MechanicalEnergy to rotae the mills. Cane passes through these rotarymills and juice is extracted from the cane by rotary motion ofthe mills leaving Baggasse behind.

No. of mills For Tandem No. 15 No. of Mills for Tandem no. 26

Mill House Output:

Screened cane juice and bagass is the output of the millhouse.

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The manager needs to process the cane as soon as possible ifsugar losses are to be avoided yet needs to have a sufficientsupply in storage for times when cutting and transport arestopped, whether deliberately or not. Typically, cane isprocessed within 24 hours of cutting;

Cane preparation is critical to good sugar extraction,particularly with diffusion extraction. This is achieved withrotating knives and sometimes hammer mills called "shredders".However shredding requires extra energy and more equipment;

Imbibitions:

The extraction is actually conducted as a counter-currentprocess using fresh hot water at one end being pumped in theopposite direction to the cane. The more water that is used, themore sugar is extracted but the more dilute the mixed juice isand hence the more energy that is required to evaporate thejuice;

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Compositions:

A typical mixed juice from extraction willcontain perhaps 15% sugar and the residual fiber, called bagass,will contain 1 to 2% sugar, about 50% moisture and some of thesand and grit from the field as "ash". A typical cane mightcontain 12 to 14% fibre which, at 50% moisture content givesabout 25 to 30 tons of bagass per 100 tons of cane or 10 tons ofsugar

Boiler House : A boiler is a closed vessel in which water or other fluidis heated

Types of Boilers: 1. Water Tube Boiler: In water tube Boiler a number ofwater tubes are arranged in and around the furnace.Watercirculates in the tubes and outside is the fire. This typegenerally gives high steam production rates, but less storagecapacity. water tube boilers are also capable of highefficiencies and can generate saturated or superheated steam

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2. Fire Tube Boiler:

In fire Tube Boiler There is a fire inthe tubes and water is present outside the tubes in the bigvessel or cylinderical drum. Fire-tube boilers usually have acomparatively low rate of steam production, but high steamstorage capacity

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The type of boiler in use in Shakrganj mill is the water tubeboiler. The number of boilers are 3. These boilers use Baggasseor SUI gas as their fuel. In off season, SUI gas gas is use forthe production of the steam because no availability of thebaggase. The baggase fed to boilers is that coming from theMill House Teandem o.1 and 2 and it contains 50% moisture.

The working conditions of these Boilers are as followed:

Steam Temperature 325-350 C Working Pressure 23-24 kg/ g.cm2

Boiler Fans:

ID Fan (Induced Draught Fan): Induced draught fan draw gasesout of the boiler. The gas has already passed through the airheaters and precipitators before it has reached these fans.

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FD Fan (Forced Draught Fan):

It takes air from atmosphere andpasses it through the air pre-heater tubes, which is then blowninto the furnace from its base through dumping gate. This warmair helps in combustion and spreading bagasse. Each unit hasforced draught fan. The fan draws warm air from the top of theboiler house through large air heaters becoming the primary andsecondary air used for the boiler combustion process. The airheater warms the incoming air by transferring heat energy fromthe outgoing flue gases.

SD Fan (Secondary Fan): Secondary Fan is also admittedturbulently to complete the combustion. This fan supplies air tothe furnace from the bottom surface to ensure completecombustion. This fan is only used when Bagasse is used as fuelotherwise it is kept off.

Super heater: A super heater is a device in a boiler thatheats the steam generated by the boiler again, increasing itsthermal energy and decreasing the likelihood that it willcondense inside the header. Super heaters increase the efficiency of the boiler, and werewidely adopted. Steam which has been superheated is logicallyknown as super heated steam.

Air Pre-heater:

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This air pre-heater is used to heat the air inductedto the boiler by the hot flue gases. Thus raising thetemperature of inlet air up to 110 C.Economizer:

Flue gases from large boilers are typically 450 -650°F.Economizers recover some of this heat for pre-heatingwater. The water is most often used for boiler make-up water orsome other need that coincides with boiler operation.Economizers should be considered as an efficiency measure whenlarge amounts of make-up water are used

Key Factors For Boiler Efficiency Calculations:

Flue gas temperature (Stack temperature) Fuel specification Excess air Ambient air temperature Radiation and convection losses.

Boiler Water treatment Plant: There are two plants for treatment of water that is fedto the boiler.

Reverse osmosis plant Demineralization plant

Why we need Water Treatment…?

Impure water may cause many problems in the boiler soit must be pured someway to avoid problems in the boiler. Themost common problems caused by the impure water are asfollowed:

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Scaling:

Total hardness in the water if not properly removedwill cause in scale formation. A layer of scale on the metalsurface of the boiler will acts as an insulator and reduce therate of heat transfer from hot zone to water. Scaling results in

More fuel will be used to maintain boiler output atacceptable level

Since heat transfer is retarded the metal become hotterto a point where it deforms and even rapture with disastrousresults

Corrosion: The most common source of corrosion in boiler systems isdissolved gas: oxygen, carbon dioxide and ammonia. Of these,oxygen is the most aggressive. The importance of eliminatingoxygen as a source of pitting and iron deposition cannot beover-emphasized. Even small concentrations of this gas can causeserious corrosion problems

Sludge formation:The impurities which are floating on the surface in the form oflight fluffy mass are called sludge’s .These are insolubleimpurities that float at the surface of water at hightemperature. Treatment is as follows: The impurities of Na , Ca , Mg ,react withant scaling agent and form their sulphates and phosphateswhich are easily removed. However due to sludge formation therate of water evaporation is decreased .The sludge formation

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starts at 40oc and maximum sludge is produced at 80oc, at thistemperature it is automatically drained off.

Reverse Osmosis Plant: Reverse osmosis plants have at their heart a membranethat if damaged reduces output, increases costs and gives poorwater quality so it is important to keep it clean and operatingefficiently. Most reverse osmosis membranes are formed from hollow fibre orthin film composite sheets with the membrane allowing passage ofpure water and rejecting the dissolved solids contained in thewater. As water passes along the membrane surface the solidsconcentration increases and some sparingly soluble salts startto exceed their solubility and precipitate. When precipitatedonto the membrane surface this causes fouling that may reduceoutput and increase product water conductivity. The worst ofthese solids being calcium carbonate and calcium sulphate and sothe prevention of their precipitation is vital if the membraneis to function efficiently.

Demineralization plant:

A Demineralisation Plantconsists of two pressure vessels containing cation and anionexchange resins. Various types of ion exchange resins can beused for both the cation and the anion process, depending on thetype of impurities in the water and what the final water is usedfor. Typically, the cation resin operates in the hydrogen cycle.The cat ions in the water (i.e. calcium, magnesium and sodium)

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pass through the cation exchange resin where they are chemicallyexchanged for hydrogen ions. The water then passes through the anion exchangeresin where the anions (i.e. chloride, sulphate, nitrate andbicarbonate) are chemically exchanged for hydroxide ions. Thefinal water from this process consists essentially of hydrogenions and hydroxide ions, which is the chemical composition ofpure water. Simple demineralisation plant consist of Compositeresin vessels with charge of strong cation and anion resin;control-panel encompassing a conductivity measurement andalarms, etc; acid and caustic injection facility from bulk,semi-bulk or carboy containers.

Deaerator:

purposes of deaeration are: To remove oxygen, carbon dioxide and other non-condensable

Gases from feed water. To heat the incoming makeup water and return condensate to

an optimum temperature for:

i. Minimizing solubility of the undesirable gases

ii. Providing the highest temperature water forinjection to the boiler

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PowerHouse :

Power house use s steam produced bythe boiler house to generate electric power.In power house firstheat energy of steam is converted in mechanical energy byturbines and then mechanical energy is converted into electricalenergy by the help of generators.In Shakarganj mills two different types of turbines are used forthe creation of mechanical energy:

Back pressure Turbines Condensing Turbines

Back Pressure Turbine:

First three Turbines in the powerhouse arebackpressure Impulse Turbines. Backpressure means that theexhaust of these turbines is not also steam of pressure abovethan atmospheric pressure. Noncondensing or backpressureturbines are most widely used for process steam applications.The exhaust pressure is controlled by a regulating valve tosuit the needs of the process steam pressure. These arecommonly found at refineries, district heating units, pulpand paper plants, and desalination facilities where largeamounts of low pressure process steam is available.

Advantages of Back pressure Turbines:

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1- Process Heat For various Operating loads can be provided.2- Electrical power to meet the own and for Feeding into the

Public grid is available.3- Balancing of operational Fluctuations between Power and

steam requirement.4- Avoidance of exceeding the maximum Demand limits for power

imported from the Public grid.

Condensed Turbines:

Condensing turbines are most commonly found inelectrical power plants. These turbines exhaust steam in apartially condensed state, typically of a quality near 90%, at apressure well below atmospheric to a condenser.

Production House

Juice that is coming from milling house hasfollowing properties;

Acidic Opaque Greenish color Brix (thickness) 10 – 15 Soluble impurities

Insoluble impurities like proteins, waxes, gums etc.

Physical and chemical processes are required for the productionof sugar. These operations carried out in process house.

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Main units in process house are:

Primary Heaters: Juice which is coming from Tandem 1 andTandem 2 is pumped to primary heaters, there are three primaryheaters for tandem 1 and tandem 2, two set for each tandem.Heaters used for heating juice coming from tandem 1 is calledprimary heaters set no.1 and that is used for heating juice oftandem 2 is called primary heater set no. 2. These are shell andtube heaters, heating are done by vapors coming fromevaporators, juice moves in tube side and vapors in shell side,duplex valves are used for the transfer of juice in heaters.Heating is done for proper reaction with lime in reaction tank.

Juice heating temperature60-770C

Defication tanks:

Defecation is process of removal ofimpurities by the action of lime and heating. Defication iscarried out in following equipments

Lime Dozer:

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Juice coming from primary heater set no. 1 andprimary heater set no. 2 enters in lime dozer from top. Here weadd lime {Ca (OH)2} to it.

CaO + H2O Ca (OH) 2

Lime is used to combine impurities that is present in juicebecause juice is acidic in nature and when lime is added whichis basic in nature then pH is maintained at 7.8 to 8.2.

Retention Tanks:

In retention tanks juice enters from thebottom. The object of these tanks is to mix juice with lime andto give the reaction to lime and juice and reaction time isprovided. There are four retention tanks in SML. In retentiontanks plates are arranged in manner that one plate is below andother is above, this arrangement is done for proper mixing andmixing is done by agitation.

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Defecation Tanks:There are two defecation tanks in SML. Juice coming fromretention tanks enters in defecation tanks separately. Fromdefecation tanks juice is pumped to the secondary heaters.Twocentrifugal pumps are attached to each tank pumping the juice tothe secondary heaters.

Secondary heaters:

Neutralized juice coming from defecation tank no.1and defecation tank no.2 is heated in secondary heaters set no.1 and secondary heaters set no.2 respectively. These are totaleight (8) in numbers and four (4) for each set. Heating media infirst three secondary heaters is vapors that is coming fromevaporators and in forth one heating is done by exhaust stream(stream that is exhausted from turbine). Exhaust stream is used

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because we require high temperature to clarifier the juice andvapors can’t do this job.

Juice heating temperature100 - 1050C

Flash Tank:

Juice that is heated in secondary heaters setno.1 and secondary heater set no. 2 is now brought to flashtank with the help of duplex valves (to bypass the juice).Flashtank is simply a conical tank where juice is entered from theside of conical section. There are four(4) flash tanks one foreach clarifier. It helps in removing vapors and to avoidbubbling of heated juice in Clarifier. The purpose of flash tankis to remove non condensable gases and air from juice. Now juiceis transferred to next equipment from bottom of flash tank.

Clarifiers:

There are four (4) clarifiers. Clarifiers are used for theclarification of juice. Bagasse and mud are removed here.Polyelectrolyte (poly acryl amide) solution is added in clarifierfrom coagulation tank (tank where solution is prepared) . Thestock solution of polyelectrolyte is prepared in one tank andthen diluted in two tanks. The dose of polyelectrolyte is inppm. The stock solution of polyelectrolyte is prepared before 8-10 hours. There are two coagulation tanks in SML one issufficient for two clarifiers. Overflow Juice from clarifier iscollected in juice tank at the side of clarifier then it ispassed through 80- mesh screen where particles present in juiceare removed then it sent to clear juice tank.

In sugar industry, clarifiers are the complicated and moresensitive point. These clarifiers are actually responsible to

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run an industry or shut down. It is the process where the juiceis clarified.

Mud Level in Clarifiers:

The mud level in the clarifiers isdetermined by dipping iron rod with thread. When it touches themud, the length of the thread is measured and we came to knowthe level of the mud in clarifiers. Then the clear juice ispassed through 60 to 80mesh plate into the clear tank. Thisjuice must be clear. If juice is not clear, then it increasesmany problems

Suspended and dissolved particles decrease brix inevaporators due to scale formation.

More energy is required to get same level of brix ofsyrup.

The sugar produced contains fibrous material asforeign matter

Mud Boot:

Impurities which are settle down inclarifier are collected in tank known as mud boot placed at thebottom of the clarifier. There are four mud boots, one for eachclarifier.

BD (begasse dust) Mixer:

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Mud from mud boot is pumped to BD mixer andbaggasse from mill house is added with the help of conveyer. Itis simply a vessel and baggasse is added just to increase poresize of mud so that we can easily separate juice from mud

Vacuum Filter:

Mixture of mud and baggasse is brought to vacuumfilter. There are ten (10) vacuum filters in SGL.Here vacuumpressure about 30-35 cm Hg is applied by the vacuum pumps.Vacuumfilters are use to remove sweetness from mud. This drum rotatesat a very slow speed i.e. 0.5 rpm. When it is rotated, mudbecome attached with the walls and at the same time mud istreated with hot water from the top.

Sweetness of input juice = 75%

Sweetness in output juice = 2-2.5%

Clear juice goes to turbid juice tank and then to reactiontank for further clarification.Mud is sent to bio-compostingplant where after composting with stillage (waste of distillery)bio-compost is prepared.

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Preheaters: Clear juice after screening goes to preheaters wherejuice is heated up to 1050C.There are two(2) prheaters inSML.Juice is preheated before evaporation.

Juice heating temperature100 - 1050C

Evaporators:

The clarified juice (85% water) in clear juicetank is pumped to evaporators where it is concentrated to aheavy clear syrup. Evaporation is done in multiple effectevaporators to achieve maximum steam economy .Each effect isarranged in series and operated so that each succeeding oneoperates under high vacuum (low pressure). This arrangementallows the juice to be drawn from one vessel to the next andpermits it to boil at low temperature.

Evaporation is done in two stages. The first in anevaporator station to concentrate the solution and second in avacuum pan is to crystallize the sugar from solution. First stepis done generally in multiple effect evaporators for improvedthermal economy; and second is performed in single effectvessels e.g vacuum pans to control the batch crystallization.The evaporator station in raw sugar manufacture typicallyremoves 90% of the water from the clarified juice from about 15brix to about 65-70 brix. There are different terms, which areused here in factory for evaporators, bodies and quads are more

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common. When four bodies are combined then it is called quad.Thetriple, quintuple-effect evaporators are also used butquadruple-effect type is more common. In this one pound of steamevaporates four pounds of water.

Juice from clarifiers goes to the vapor cell. Vapor cellis used before each quad for steam economy . There are threevapors cells. The exhaust Steam is applied on vapor cell andtemperature is raised to about 110oC.Then juice goes toevaporator No.1. Its temperature is kept at 110o C. The Vapors of1st body are used in 2nd body as heating media and hence there isno use of steam in body No.2.

The temperature of 3rd and 4th body is 85oC and 60o C respectively.Creating vacuum of 60-65 mm Hg decreases the temperature of 4thbody. The 4th evaporator is attached with condenser, whichremoves condensable gases through jet and condenses the vaporsby spraying the cold water. Syrup of 60 to 65 brix is obtainedfrom the 4th evaporator. Then this syrup is sent to syrup tankscalled syrup storage tank. The cleaning of evaporator is

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necessary to maintain the brix. After 12-15 days everyevaporator has to be cleaned.

Juice Temperature Brix Pressure

Clear juice 890C 15 1 kg / cm2

Vapour cell 1040C 22 0.33 kg / cm2

Evaporator 1 1030C 35 0.29 kg / cm2

Evaporator 2 930C 38 0.11 kg / cm2

Evaporator 3 89 0C 41 -28.13 kg / cm2

Evaporator 4 580C 65 -53.63 kg / cm2

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Syrup storage tank: Syrup from syrup storage tanks is sent to syrupstorage tank,from there it is sent to raw crystallization pans.

Raw crystallization:

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Syrup from evaporators is pumped to avacuum pan in which it is evaporated to supersaturation inorder to cause sugar to crystallize .This is done in panswhich may be either Batch pan or Continuous vacuum pans

The function pan is to produce satisfactory sugar crystals fromsyrup. The concentration of feed used in pans is usually 60-65brix and may reach to 74 here.

These pans are specified for different boiling of differentmassecuite and seeds.

Batch Pan # 1,2 Seed for A massecuite, Continuous Pan # 1,2 forA-massecuite ,Batch Pan # 3 seed for c-massecuite, Continuouspan # 3 for c- massecuite and Batch Pan # 4,5,6,7,8 for B-massecuite

Massecuite = molasses + crystals

Crystallization is done through following pans that workmutually.

A panB pan C pan

A pan:

Syrup from syrup storage tank is taken into Apan. Through vacuum boiling brix level is increased to 70, wherecrystals start to form. Vacuum boiling (pressure 76 mm Hg) isdone at 60C. Now A massecuite is done by the addition of B seed(added up to 1/4 or 1/8 of total tank volume). Here A grain (brix90-95) is formed that is further transfer to continuous vacuum

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pans continuous vacuum pans consists of 12 parts where syrup andA grain is brought in contact to each other in tubes and steamis applied as heating media.

The product from continous pans is A massecuite and thatis dropped into A crystallizer by vacuum breakage. Sugar isformed within three to four hours.

This material is further transferred to A centrifugalswhere high. In centrifugals speed is applied separate grain ofsugar and molasses comes out. These machines work mechanically,centrifugal force works when basket of the centrifugal rotateswith high speed i.e. 1600 rpm.

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There are 10 Nos. of A-centrifugals, 9 Nos. of Bcentrifugals, 8 Nos. of C centrifugals. From the centrifugationof massecuite A, A melt, A heavy and A wash are obtained. Rawmelt is sent for clarification while A heavy and A wash arebrought into B pans for preparation of massecuite B.

B Pan:

There are five nos. of B pans in SML. Physicalparameters are same as that is pan A. Here B massecuite isformed which is dropped into B crystallizer. Centrifugation ofmassecuite gives B seed and B heavy.

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First of all B seed that is used for A massecuite isprepared by slurry ( crystals + isopropyl alcohol) and syrup.Isopropyl alcohol is added for proper size of grains.

C Pan:

There is a single C pan in SML. Here Cmassecuite is prepared from B heavy taken from B pans andslurry. Here C grains are formed that are than dropped to Ccontinuous pan where syrup is added and product is than sent tovertical crystallizers( two in numbers) then it is sent tocassettes (four in numbers)where temperature is dropped to 40Cwhich is best temp. For crystallization.

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Then it is sent to re-heaters (four in numbers) Thepurpose of re-heaters is to increase the temp. of massecuite tosuch a level suitable for centrifugation. Centrifugation (singlecuring centrifuges) of massecuite C gives C seed along withfinal molasses. This final molasses is sent to distillery forproduction of alcohol. C seed is sent to double curingcentrifuges from where we get C Light (purity 56 to 58) and Cseed that is used for preparation of soft sugar.

Sugar Refining: The raw sugar produced in industry as described inpreceding section is LIGHT BROWN in color and contains 98%sucrose .In order for it to be competitive for marketplace, it

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is necessary to bring about level of sucrose to 99.9% to make itwhite.

There are four routes for production of white sugarfrom sugar cane or raw cane sugar. (1): traditional plantationwhite , obtained directly from sugar juice with settlingclarification and sulfitation. (2): improved plantation whitewith carbonation and sulfitation. (3): refined white, from awhite end refinery attached to raw sugar factory, involvingremelting raw sugar and refinery classification and decolorizingprocess; and (4) refined white, refinery not incorporated intoraw sugar factory.

Phosphitation Process: A-melt which is the final product of the raw process isfurther transferred for melt clarification. The process involvesfollowing steps:

Buffer tank: Raw melt goes into buffer tank. Its purpose is tostore the raw melt. The capacity of buffer tank is 65 cubicmeter.

Supply tank:

Raw melt from buffer tank comes into supply tank situatedat ground flour.

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Liquor Heaters: Liquor from supply tank is sent to liquor heatersfor heating up to 80 to 85C that is suitable for purification.Melt is heated so that it may be reacted efficiently and to getoptimum Condition. Juice heating temperature80 - 850C

Reaction tank:

After heating the product is taken into reactiontank. In reaction tank following chemicals are added:

Phosphoric acid (300-400 ppm) Talofloc : It is used as decolorizing agent Talofloat: It is used to float the ppt. sludge, colloidal

solution so that it can easily removed from the upper

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surface. Lime Socrates: To maintain the pH of the raw melt.

Telo Clarifiers:

From reaction tank the liquor comes in teloclarifiers. Due to the addition of low molecular weightcoagulants (Taloflot), the mud floats on the surface of liquor.Here mud is collected with the help of scrappers and sent tovacuum filters. Liquor is collected into liquor tank and sentfor sulphitation.

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Sulfitation/sulfur tank:

Sulphitation is aneminent process done to decolorize the liquor. For this purposeliquor is taken in a tank and SO2 is passed from the bottom ofthis tank. SO2 is removed from top of tower. Sulphur dioxide ispassed through clear liquor to give brightness to liquor Aftersulphitation liquor is collected into smear tank and then passesthrough pressure filters with the help of pumps.

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Filtration:

The liquor from phosphatation/carbonation/ sulphitation clarifiers contain small amount offinely dispersed particulate matter that require filtrationfor removal . This process is done in the pressure filters.

Pressure filters: There are eight pressure filters in SML, four are big andfour are small. Small press. Filters have 48 plates and 24 outlet and large press. Filters have 36 plates and 24 out let. Heresmall dust particles are removed and clear liquor is obtained.Pressure upto 1-2 kg / cm2.

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Deep Bed Filters: Liquor from vacuum filters is sent to deep bed filterswhere layers of different sizes of stones are applied forfurther filtration. Fine liquor is dropped from top and movestowards bottom. There are 4 large containers for this purposeand each contain three different layers of different materials.

i. Carbonii. Sandiii. Small stones

All these three materials are so stable thateven concentrated acids and base have No effect on them. It isused to remove the dust particles as well as other smallparticles In the liquor. There are layers of different sizedsmall stones of 3mm, 6mm, 12mm and 18mm.

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Decolourization:

The filtered clarified liquor is a clear, darkbrown liquid having solid contents b/w 55 to 65 Brix, a pH of 6.7 to 7.2 and temperature b/w 65-----85oc. Atthis stage certain decolorizing agents are added to removecolour such as charcoal ,bone char , ion exchange resins etcand this send for refine crystallization and centrifugationin the refine pans and centrifugals which are discussed asnext topic .

Refine crystallization and centrifugation:

Clear liquor obtained after meltclarification is brought into refinery pans for finalcrystallization. There are nine nos. refinery pans in SML. First of all massecuite is drawn from refinerycrystallizer at 200 rpm. Then this massecuite is washed with hotwater coming from nozzles. Water comes out for few seconds. Thepurpose of washing is to wash the sugar and to make it white.When hot water stops, then steam comes from the same nozzle forfew seconds. The purpose of this steaming is to dry the sugar.Centrifugal rotates with high speed almost to 1600 rpm. Thenmachine starts to stop with low speed. It rotates with 50rpm.Then centrifugal is discharged by dropping the sugar into thehopper. In refinery centrifugal we can refine 1500 kg sugar atonce.

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Packaging and storing of refined granulatedsugar:

In recentdecades, there have been significant changes in the methods ofhandling refined sugar as it leaves the dryer. Bulk delivery ofrefined granulated sugar to customers has made it necessaryfor the refiner to store finished products in bulk ratherthan in bags .Granulated sugar remains free flowing for a longperiod of time if it is CONDITIONED as conditioning reducesthe handling , packaging and storing problems resulting fromcaking.Conditioning involves following factors , includingcontrol of moisture contents , the temperature ,and grain size ,as well as good inventory management .

References: en.wikipedia.org/wiki/Cane_sugar_mill

www.essortment.com/ process -making- sugar -419

kiranpalwasha.blogspot.com/.../some-videos-from-sugar-mill-process..

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http://www.essortment.com/process-making-sugar-419


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www. sugar australia.com.au/Industry.aspx? content= Milling Business

www05.abb.com/global/scot/...nsf/.../a-n-sugar_ph_sulfitation_a.pd

www.clarencetourism.com/media/docs/sugarcane.pdf - Australia

http://www.acfa.com.au/index.php?option=com_k2&view=item&layout=item&id=100&Itemid=135

http://www.rudolphresearch.com/refractometers/how-to-choose/sugar.php

http://www.citehr.com/research-sugar-mill-process-page1.html?status=closed

://ethanolfacts.com.au/sugarprocess

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http://ethanolfacts.com.au/sugarprocess



http://www.rudolphresearch.com/refractometers/how-to-choose/sugar.php



http://www.sugaraustralia.com.au/Industry.aspx?content=MillingBusiness

http://www.sugaraustralia.com.au/Industry.aspx?content=MillingBusiness

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