The ppt is on milling house and boiling house in a sugar industry.

1. SUGAR INDUSTRY
(MILLING AND BOILING HOUSE)

2. CONTENTS :-
1). Flow diagram of the industry
2). Houses
3). Milling house
4). Boiling house
5). Drier
6). Boiler
7). Power house
8). Exhaust

4. Houses
There are following houses in the industry.
1) Milling house
2) Boiling house
3) Pan house
4) Drier house
5) Power house

5. Milling house
Introduction-
Milling is the process by which most of the sugar factories in the world
extract juice from sugarcane.
Now the milling plants are capable of achieving higher extraction of the
order 95-97% with higher crushing rates and reduction in power
consumption by following modern milling techniques.
The major developments were in the field of cane preparation devices, cane
feed devices and mill design.

6. Design aspects:
The following aspects should be taken into a count, when designing or
selecting mill housing:
The apex angle (top angle) should be minimum

7. Three Roller mill arrangement

9. MILL FEEDING DEVICES
There are following types-
1) Donnelly chute
2) Under feeder roller
3) Toothed toller pressure feeder (T.R.P.F)
4) Groove roller pressure feeder (G.R.P.F)
Advantages of mill feeding devices
1. It increases increases crushing rate by 25 to 30%.
2. Better self feeding due to positive feeding of cane without sleepage.this also
increases mill capacity and extraction.
3. Mill extraction increases by 0.25 to 0.30 %.

10. Donnelly chute with under feeder roller

11. Donnelly chute with under feeder roller

12. MILL HYDRAULIC SYSTEM
PURPOSE-
The purpose of using hydraulic pressure system is to maintain a constant pressure,
independent of the lift of the roller.
CAPACITY
Capacity of Mill: The quantity of cane passes through the mill in unit time. It is
generally expressed in Tons per hour (TCH) or Tons per Day (TCD).
Capacity of the mill = Total quantity of cane crushed / total no. of hours the
mill worked

13. MILL IMBIBITION
Even when bagasse is subjected to high and repeated pressure it never gives up all
juices it contains.
With dry crushing extraction of juice is only 86 %
It is not possible to remove all the sugar from bagasse by applying repeated
application of heavy hydraulic pressures. It retains qty of juice approximately equal
to weight of fibre i.e 50%.
Thus in order to obtained maximum extraction of juice as much as possible of
sugar which it remains , it is therefore necessary to apply dilute juice / water to
bagasse top enhance the extraction of juice at the next mill. This process is called
“IMBIBITION” . This term also applied to the fluid used for the purpose.
It is observed that with increase in 1% imbibition on fibre to increase in
extraction is 0.01 units

14. TYPES OF IMBIBITION
1. Simple imbibition
2.Compound imbibition
Simple imbibition
This system however, whole qty of is added on only last mill and juice send to
process
Compound imbibition
This system however, consumes much water which has to be evaporated later.
Starting from simple imbibition it has been observed that the diluted juice
extracted from the last mill is mostly water. It has been and sent back before the
preceding mill. This is what is called compound Imbibition.

16. Introduction:
• After Combustion heat is transferred into water till it heated and becomes hot
water / steam.
• The hot water or steam under pressure is then usable for transferring the heat
to process.
• Water is a useful and cheap medium for transferring heat to a process. When
water is boiled into steam, its volume increases around 1,600 times, producing
a force that is almost as explosive as gunpowder. This causes the boiler to be
extremely dangerous equipment and it must be taken care. The process of
heating a liquid until reaches its gaseous state is called evaporation.
Heat is transferred from one body to another:
1.Radiation - Transfer of heat from a hot body to a cold body without medium
2.Convection - The transfer of heat by medium, such as air or water
3.Conduction- transfer of heat by actual physical contact and molecule to
molecule.

17. STEAM BOILER IN SUGAR INDUSTRY
The function of boiler is to generate steam at desired pressure and temp. by
transferring heat producing by burning of fuel( Bagasse) from water to change into
steam.
Steam boiler is heart of sugar factory. If any breakdown is occurred at steam boiler,
whole sugar factory is stopped indefinitely till the boiler is repaired.
The steam produced is used for :
(i) Producing mechanical work by expanding it in steam engine or steam turbine.
(ii) Heating the residential and industrial buildings
(iii) Performing certain processes in the sugar mills, chemical and textile industries.

18. Classification of Boiler
According to the direction of the axis of the shell
• Vertical
• Horizontal
• Inclined (sometimes)
According to the service to which the boiler is placed
• Stationary (Power plant, Industrial, Central heating)
• Portable
• Locomotive
According to the Heat transfer Mode
Fire Tube Boiler (water is outside the tube while the hot gas are inside the tube)
Ex. Cohran, Lancashire, Cornish, Locomotive etc…

19. Water Tube Boiler ( Contain large number of small tube through which water
circulates the fire and hot gas being outside the tubes.)
Ex. Babcock & Wilcox, Striling and high pressure Boilers)
Steam Boilers
Boiler is defined as a closed metallic vessel in which the water is
converted into steam above the atmospheric pressure by the application of heat
generated by the combustion of fuels.
Function of a Boiler
The function of a boiler is to generate & supply the steam at the
required constant pressure with its quality either dry, wet or superheated.

23. Advantages of Water Tube Boilers over Fire Tube Boilers
1. Steam can be raised more quickly
2. Steam at higher pressures can be produced
3. Higher rate of evaporation
4. Sediment deposition is less
5. Suitable for any type of fuel and method of firing
6. Failure of one of the water tube will not affect the working of boiler
7. Occupies less Space
8. Easy maintenance.

24. BOILER MOUNTINGS
• Boiler mountings are required
• To have complete control over the steam generation
• Measurement of some of the important steam parameters
• To provide safety to the boiler.
According to boiler act, The Boiler mountings are:
1) Pressure Gauge
2) Safety Valves
3) Water level Indicators
4) Feed Check Valves
5) Steam Stop Valve
6) Man Holes & mud Holes

25. BOILER AUXILIARIES
Boiler Auxiliaries are required in the boiler circuit to increase the
boiler efficiency
Boiler Auxiliaries :
1) Air Pre heater
2) Economizer
3) Super Heater
4) Boiler Feed Pump
5) Steam trap

26. How to Improve the boiler Efficiency
* To increase the Calorific Value of Bagasse
* To reduce the Losses of Boiler
* To clean the H.S.of Boiler
* To keep Excess Air % proper
* To use the quality water in the boiler
* To keep the CO2 percentage at 14.5 %
* Percentage of CO Should not be increased above 0.5
* Steam traps, valves , pipes should be made leak proof
* soot blower and blow down should be regular
* The boiler furnace should be cleaned in the running season shift wise

27. COMBUSTION OF BAGASSE
Inlet to the furnace:
i) Bagasse, which contains C, O2, H2 & H2O as moisture
ii) Air for combustion contains O2and N2.
Outlet from furnace
i) C + O2 =CO2,
ii) 2H2+ O2 =2H2O (water vapour) also water vapour of moisture of bag.
iii) O2 as excess O2 from bagasse or air
iv) N2 from air

28. COMBUSTION PRODUCT

29. Steam Distribution at various station in Factory
Station % Ex. Steam required on Cane
Juice Heater 15-18
Evaporator 2-10
Pan Boiling 20-25
Sulphur Burner Etc. 3-5

30. Steam Turbines:
Types of turbines:
1)Impulse & reaction turbines: single stage ,Back pressure &condensing .
*Impulse turbine: When total pressure drop in nozzle only then it is called impulse
turbine.
*Reaction turbines: When pressure drop in fixed nozzle & Blades is called as
reaction turbine.
*Condensing turbine: condensing turbine is turbine whose exhaust connection is
connected to a condenser.
*Back Pressure turbine: Where the steam leaves the turbine with certain pressure
to the process

31. Work’s on rankine cylcle