Report (Mill and Boiler Final)

7/31/2019 Report (Mill and Boiler Final)

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Universal Robina Corporation

Universal Robina Sugar Milling Company

Manjuyod, Negros Oriental

The Mill and Boiler

By:

Rommel LitoNepalarJaypeeTimanuno

Richard Mark Zamora


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Mill and Boiler Department

Objectives:

To mill canes and maximize juice extraction at the right time inaccordance to costumers satisfaction

To supply enough bagasse to boilers for efficient operation To generate steam required for smooth flow of the operation To execute organizational goal conforming to manufacturing plan and

quality plan


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MILLING

The extraction of juice from Cane constitutes the first stage of the entire process of cane sugar

manufacture wherein the object of separation of juice from the fibrous portion of the cane is accomplish

by employing heavy machinery. It begins by dumping of canes at the dumping station. Before dumping,

canes are weighed to serve as method for payment to growers. Canes are arranged by batch in the

dumping area. Then, the canes are being conveyed by the feeding carrier. The speed of the carrier is

being controlled by an operator in the tower. It has a leveller which levels the cane and a kicker.

Theleveller rotates in a direction opposite to the direction of the feeding carrier while the kicker rotates

opposite in the direction of the leveller. Afterwards, the cane moves to the cane carrier which carries

the cane to the shredder. As the cane move towards the shredder, it passes through levellers and

cutters. The cane first passes through the first cane leveller. Then the cane passes through the two

cutters which cuts the cane into smaller pieces, with different clearance and the number of blades. Cane

cutter number has twice the number of blades as the first cutter. Then the cane moves to the kicker

which kicks the cane to the shredder.

Note:

(a)The sugarcane plant is essentially composed of two types of fiber, the interior soft pith which

`holds sugar rich juice and the outer portion known as rind, containing juice with high

impurities.

(b)The feeding carrier and the cane carrier are an apron type conveyor.

Parameters


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Leveller #1 (Cane Carrier)

Motor Speed: 1770 rpm

Power: 55 kw

Reduction: 1:43.192

Leveller (Feeding Carrier)


Power: 55 kw

Reduction: 1:43.192

Kicker (Feeding Carrier)


Power: 55 kw

Reduction: 1:43.192

C C # 1 ( d i )


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Cane Cutter #2 (turbine driven)

Turbine speed: 4000 rpm

Reduction: 1:7:52

Knife quality: Hard facing build-up on knife edge

(19mm T x 210mm W x 613mm L)

Clearance (40-60) mm

From tip of the knife to cane carrier slats

Pitch/ number: 56 piecesTurbine Steam Supply Pressure: 182 kgf/cm

2

Turbine Chest Pressure: 6-13 kgf/cm2

Turbine exhaust Pressure: 1.5 kgf/cm2

Oil Lubrication Supply pressure: 0.5-2 kgf/cm2

Bearing Temperature: not more than 75C

Oil Temperature: not more than 60C

Water Temperature : not more than 55C

Leveller #2 (Cane Carrier)

Motor Speed: 1750 rpmPower: 22 kw

Reduction: 1:32


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The Iron Separator

Iron separators are installed in the mill to separate metals which goes together with the canes. It is

really important to separate metals because it may damage the mill rollers and most especially interruptthe operation. The efficiency of these separators in removing iron pieces and thus avoiding damage to

processing equipment is 80-90%. The commonest objects are: pieces of knife-blades, bolts and nuts.

Pieces of cast iron or special steel are the most dangerous. Whether it is detected in time or not such

incidents are expensive.

The Shredder

The shredder is essentially a hammer mill adapted to the function of sugarcane pulverising. It composed

of 88 swing type hammers arranged into 11 rows. Each row has 8 hammers which revolves on pivot. As

the name indicates, the equipment shreds or tears the cane to pieces or pulverises it into long fluffy

material which in effect increases the extraction of the mill. Shredder is always preceded by usual two

sets of cutters and levellers which cut the cane prior to feeding the shredder.

Cane Shredder

Hammer Quality Hard facing build up

No. of Hammer 88 pcs.

Cutting Bar Quality Carbon steel with hard facing build up

Number of Cutting Bars 7 lengths

Clearance: inlet (30-40)mm

Discharge (45-55)mm

Turbine average speed 3500 rpm

Steam supply Pressure 182 kgf/cm2

Chest Pressure 7-14 kgf/cm2

Exhaust Pressure 1.5 kgf/cm2

Oil L b i ti l 0 5 2 k f/2


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(1) To provide passage for juice extracted on compression(2) To disintegrate the bagasse to facilitate juice extraction

The pure juice of the 1st

mill is collected by the mixed juice tank and is pumped to the rotary screenfilter. The rotary screen filter, filters the bagasse that mixed with the juice. After the 1

stmill, the bagasse

is transported to the 2nd

mil by an intermediate carrier. An intermediate carrier is a rake type of

conveyor as well as the shredded cane elevator. The bagasse drops to a chute, passed to the pusher roll

and the mill rollers. Same goes with the 3rd

, 4th

, and 5th

mill.The juice that is collected by the 5th

mill will

be pump to the 4th

mill, the 4th

mill to the 3rd

mill and the 3rd

mill to the 2nd

mill. the mixed juice of the 2nd

mill will be pumped to the rotary screen filter together with the pure juice of the 1 st mill. the bagasse

that is filtered by the screen filter will be conveyed by a screw conveyor to the intermediate carrier ofthe 2nd mill. The bagasse that exits the 5th mill will be carried by the main bagasse elevator. The final

bagasse will be used by the boilers as fuels.

The bagasse that exits the 5th

mill must not be wet to avoid low steam pressure.

Standard Mill Openings

Standard Mill Openings

Mill Feed roller

to top roller

Discharge roller

to top roller

1 80 mm 40 mm

2 95 mm 45 mm

3 90 mm 40 mm4 75 mm 35 mm

5 60 mm 34 mm


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The input speed above are the maximum speed of the turbine. The current speeds that are used in the

mills are the following: 2700 rpm (mill 1), 3800 rpm (mill 2), 3400 rpm (mill 3), 3900 (mill 4), and

3200rpm (mill 5). The governor is an auxiliary part of the mill turbine which regulates the speed of the

turbine. The shaft of the turbine is coupled in the speed reduction. Speed reduction is a series of gears

of different diameter.

Parameters Mill 1 Mill 2 Mill 3 Mill 4 Mill 5

Turbine Supply

Pressure

18 2kg/cm2

18 2kg/cm2

18 2 kg/cm2 18 2kg/cm2

18 2 kg/cm2Turbine Temperature 320 5

o

C 320 5o

C 320 5o

C 320 5o

C 320 5o

C

Turbine Speed 2600-3000

rpm

4000 rpm

max

4000 rpm

max

4400 rpm

max

4400 rpm max

Turbine Chest

Pressure

5-7 kgf/cm2

5-7 kgf/cm2

7-12 kgf/cm2

7-10

kgf/cm2

8-15 kgf/cm2

Exhaust Pressure 1.5 kgf/cm2

max

1.5 kgf/cm2

max

1.5 kgf/cm2

max

1.5 kgf/cm2

max

1.5 kgf/cm2 max

Top Roller Hydraulic

Pressure

2700 psi max 2700 psi

max

2700 psi max 2700 psi

max

2700 psi max

Mill Roller Condition

Groove Depth 65 mm 65 mm 65 mm 65 mm 65 mm

Pitch 64 mm 64 mm 64 mm 64 mm 64 mm

Extraction 77% 85% 90% 93.50% 95.80%

Milling Rate 360 tons/hr

max

360 tons/hr

max

360 tons/hr

max

360 tons/hr

max

360 tons/hr max

Maceration None (dry) Multiplecompound

maceration

Multiplecompound

maceration

Multiplecompound

maceration

Multiplecompound

maceration (40-

70 C)


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START-UP OPERATING PROCEDURE (milling section)

1. Start motor of cane carrier .2.

Turn on the cane carrier kicker.3. Switch on the AVR of the cane carrier, push ON of speed controller panel.

4. Turn the speed regulator of the cane carrier at rate speed 0-10m.5. Call the feeding carrier operator to start feeding canes.6. Inform the boiler control panel operator to start the bagasse elevator.7. Observe the thickness of the cane at cane carrier through ammeter.8. Swtich on the SCE when cutted cane reaches shredder.9. Switch ON screw conveyor and rotary screen as soon as shredded canes enter the mill.10.

Swtich ON IC no. 1 when bagasses starts to came out of the mill no. 1 and switch ON juice pumpno. 1.

11.And the switch ON screened juice pump.12.Switch ON IC NO.2 when bagasse starts to came out of mill No. 2.13.Switch ON juice pump no. 3.14.Switch ON IC no. 3 as soon as bagasse came out from mill no. 3.15.Switch ON juice pump no. 5.16.Switch ON IC no. 4 as soon as bagasse come out from mill 4.17.

Switch ON juice pump no.7.18.Signal the boiler panel operator that bagasse is now in the bagasse elevator

19. Inform the juice pan tender to open the maceration and the hot water maceration and thesprayer.

20.Switch ON interlock equipments.

SHUT DOWN PROCEDURE (milling section)

1. Switch off the interlock of equipments.


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The Boiler or Steam Generator

The remaining fibrous solids, called bagasse are burned for fuel in the steam boilers. These boilers

produce high-pressure steam. A boiler is a device for heating water or generating steam above

atmospheric pressure. All boilers consist of a separate compartment where the fuel is burned, and a

compartment where water can be evaporated into steam.

Classifications of boiler:

Fire Tube Boiler- a steam boiler in which ho gaseous products of combustion pass through tubes

surrounded by boiler water

Water Tube Boiler- a steam boiler in which water circulates within tubes and heat is applied

from outside the tubes to generate steam.

Essential elements of boiler: In starting a turbine

(1) Water Check for:(2) Air(3) Fuel (a)cooling water (b) lubrication oil(4) Fire (c) fuel(steam)

In the plant, there are three water tube type of boiler. URSUMCO boilers are Pneumatic Spreader with


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0.3Lift pump delivery pressure0.4Feed Water Temperature0.5Boiler Drum level0.6Deaerator water level0.7Boiler gas outlet0.8AH gas outlet0.9AH air outlet0.10 PFDF air outlet0.11 Furnace chamber0.12 IDF Gas inlet0.13 IDF turbines 1 and 2

0.13.1 Bearing Temp.0.13.2 Cooling Water temp.0.14 Bagasse fuel0.15 Boiler water treatment

0.6 kgf/cm2

max.

9510 C

050 mm

50mm average level27525C

21030C

15525mm HO

15050mm HO

020mm HO

-100to -150mm HO

Not more than 80CNot more than 55C

56% bagasse moisture max

Refer to boiler water treatment

Boiler 3Product

1.0High Pressure Steam

1.1Temperature

1.2Pressure

1.3 Capacity

2.0 Bleed Steam

2.1Pressure setting

Process

1.0H.P Steam1.1 Boiler water level

34020C

26 4 kgf/cm2

80 tons/hr max

182 kgf/cm2


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Ash Removal Conveyor 3

Ash Removal Conveyor 1&2

ShutterShutter

Main BagasseElevator

Main Bagasse Carrier Surplus BagasseConveyor

Travelling BagasseCarrier

Boiler # 1 Boiler # 2 Boiler # 3

Ash Bin Ash Bin

Deashing Conveyor 1&2Deashing

Conveyor 3

Air Preheater Conveyor 1&2 Air Preheater Conveyor 3

Dust Collector Conveyor 1&2 Dust Collector Conveyor 3

Bagasse and Ash Conveying System

From 5th

Mill

Return Bagasse Elevator


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Bagasse Flow

The figure above indicates how bagasse and ash are being conveyed. From the 5 th mill, the bagasse is

conveyed by the main bagasse elevator to the main bagasse carrier. The main bagasse carrier has theupper and lower portion. The lower portion carries the bagasse from the main bagasse elevator and

distributes the bagasse to the boilers. The excess bagasse drops in the shutter and is carried to the

surplus bagasse conveyor. The surplus conveyor has shutter which connects to the return bagasse

elevator. The surplus bagasse conveyor connects to the travelling belt conveyor. The travelling belt

conveyor conveys the bagasse to the bagasse warehouse. As the name implies, it is where the excess

bagasse is stored. The stored bagasse will be used if the milling operation stops. Backfeeding is the

feeding of bagasse in the return bagasse elevator using heavy equipment like payloader.

Boiler Fuel Consumption (based on maximum capacity )

1 30 tons/hr

2 30 tons/hr

3 40 tons/hr

Ash Flow

Ash and unburned bagasse drops and collected in the deashing conveyor during deashing. Deashing is

done in the 1st

hour and every after four hours of the shift. It is done periodically to minimize the

bagasse that goes with the ash in deashing Deashing is done by the fireman The fireman releases the


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(1) High pressure and temperatures of steam are desirable for generating power.(2) Low pressure steam is required in process operation.High pressure steam from boilers is fed to prime movers for some units like mill turbines as well as tothe power house turbines. And the exhaust from these prime movers is utilised for process operations.

The steam that is being generated goes to the high pressure header(HPH) and the HPH is responsible

for the distribution of steam. The exhaust steam that is produced by the turbines in the mills and

power house will go to the low pressure header and will be utilized in the process.

Boiler Feed Water

The source of water for steam for steam generation in the boilers is mostly the condensate from the

heat exchangers in the process and the condensate is derived from condensed vapour obtain from

juice boiling in the evaporators and water from steam condensed in the heat exchangers . The

condensate tank pumps water to the day tank. The day tank provides water supply in the boiler when

there is no operation. If the mill operation starts, the deaerator tank will supply water in the boiler. A

deaerator is a device that is widely used for the removal of oxygen and other dissolved gases from the

feedwater to steam-generating boilers. Exhaust steam enters the deaerator and heats up the water to

110C. The water from the deaerator is being pumped to the boiler by a feedwater pump.

Before entering the steam drum, the water enters an economizer. An economizer is a feedwater

preheating device which utilizes the heat of the flue gas. Economizers are usually made of cast iron and

their function is essentially to heat the feedwater and not to boil. When the water exits the

economizer, water temperature is now 170C. Then it enters the steam drum. It collects the steam

generated in the boiler. It must be half filled with water.

The mud drum is located below the steam drum where impurities settle. The steam drum and mud

drum is connected by the generating tubes The superheater isa bank of tubes suitably located in the

path of hot gases and connected to the boiler drum.
http://en.wikipedia.org/wiki/Gashttp://en.wikipedia.org/wiki/Feedwaterhttp://en.wikipedia.org/wiki/Boilerhttp://en.wikipedia.org/wiki/Boilerhttp://en.wikipedia.org/wiki/Feedwaterhttp://en.wikipedia.org/wiki/Gas


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valves (2 for steam drum , 1 superheater). Each safety has different settings and the valve settings are

as follows:

Boiler 1 Boiler 2 Boiler 3SV1: 24.2

SV2: 23.6

SV3: 24.3

SHV:23.5

SV1:24.9

SV2: 23.8

SV3: 24.2

SHV:23.6

SV1:34.5

SV2: 35.2

SHV:34.0

(all units are in kgf/cm2)

Boiler Water Treatment

It is necessary for the water in the boiler be treated to achieve great steam production at a lower cost.

Another reason is that the water has chemical elements it that must be controlled to limit and eliminate

the formation of scaling, corrosion and entrainment in the boiler.

Scaling may cause low heat transfer at the point of deposits. Some of the more common scale forming

constituents are silica, iron, oil, hardness and sugar. Corrosion causes development of weak spots which

could lead to failure. Corrosion may be due to chloride, iron, sugar, oil and dissolved gases such asoxygen. Entrainment is often caused by variety f soluble and suspended solids.

Chemicals were put in the high pressure and low pressure chemical injection tank to control the

formation of the chemical elements that is carried by the water to the boiler.

Dosing points Boilers 1 and 2 Boiler 3Chemical Dillution Chemical Dillution

Low Pressure Line

Chemical Tank

Diclean B-901 = 2.1 kg

Oxynon S 340FG 2 4 kg

Diclean B-901 = 1.4 kg

Oxynon S 340FG 1 6 kg


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Parameter Units Feed Boiler 1 & 2 Boiler 3

pH - 8-9.5 10.5-11.5 10-11

Electrical

Conductivity

S/cm - 3000 1000

P-alkalinity mg CaCO3/L - 500 max 120 max

M-alkalinity mg CaCO3/L - 600 max 150 max

Total Hardness mg CaCO3/L 0 0 0

Calcium Hardness mg CaCO3/L 0 0 0

Silica mg SiO2/L - - 50 max

Residual Sulfite mg/L - 10-20 5-10

Phosphate Ion mg PO4-3/L - 20-40 5-10

Chloride Ion mg Cl-

/L - 150 max 100 maxTotal Iron mg Fe/L 0.1 max - -

Sugar Presence - Absolutely negative

How to fire a boiler?

To fire a boiler, there are preparatory measures that needs to be considered:

(1)Man power(2)Operating abilities(3)Sufficient water in the drum(4)Fuel(5)Fans are in good condition(6)Base fire

If you have all of the stated above, you are ready to fire boiler. Coordinate with the process,

power house, mill and refinery that you are ready to fire a boiler. If the boiler has too much

water open the blowdown valve Open also the superheater drain to release the water residue


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Solving for Develop Boiler Horsepower

Given:

@ , and @ From Steam Tables, table 3 (Superheated)

2.05 3113.5

2.06 hs

2.1 3112.4

By interpolation; From Steam Tables, table 1 (saturated), @ ;

() Where:


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Solving for ASME Evaporation Units

ASME Evaporation Units is the heat output of the boiler or the rate at which heat is transferred. ( )

Solving for Factor of Evaporation, (FE)

Factor of Evaporation is the actual heat absorption per kilogram of steam generated divided by 2257 (h fg

from and at 1000C)

Solving for Equivalent Evaporation

Equivalent Evaporation is the product of the rate of evaporation of steam and factor of evaporation.


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Solving for Equivalent Specific Evaporation

Equivalent Specific Evaporation is the product of boiler economy and factor of evaporation.

Solving for Boiler Efficiency

( ) Where:


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For Boiler 3

Rated Boiler Horsepower

Where:

Solution:

Solving for Develop Boiler Horsepower


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From Steam Tables, table 1 (saturated) @ ;

() Where:

Solving for Percent Rating

Percent Rating is the ratio of the develop boiler horsepower to the rated boiler horsepower.


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Solving for Equivalent Evaporation

Equivalent Evaporation is the product of the rate of evaporation of steam and factor of evaporation.

Solving for Actual Specific Evaporation (ASE) or Boiler Economy

Actual Specific Evaporation (ASE) or Boiler Economy is the ratio of the mass of steam to the mass of fuel.


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WATER SOFTENERTANK

DAY TANK

CONDENSATE

TANK

EVAPOTATOR

DEAERATOR TANK

LIFT

PUMPS

BAGASSE FEEDER

MOTOR

FORCED DRAFT

FAN

INDUSCED DRAFT

FAN

BOILER FEED

PUMP

CHIMNEY

TO STEAM HEADER

BAGASSE ROOM

AIR PREHEATER


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DEAERATOR

TANK

EXHAUST STEAM

CONDENSATE

LINE

SOFTERNER WATER

TANK

TO BOILER FEDD PUMP


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STEAM DRUM

DISCHARGE


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CaneShredder

Mill no. 1Mill no. 2 Mill no. 3 Mill no. 4 Mill no. 5

Pusher Rolls

Roller Mills

ScrewConveyor

Juice Flow

Legend:

From Cane Carier

Mixed JuiceTank

Screened JuiceTank

Bagasse Flow

Mixed JuiceTank

Mixed JuiceTank

Mixed JuiceTank

To Process


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Dumping Station

Leveller

Kicker

1st Cane Leveller

Cane Cutter1 Cane Cutter2

2nd Cane Leveller

Kicker

.

Documents

Report (Mill and Boiler Final)