SUGAR MILL

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ContentsSugar Mill..................................................................1

Raw Sugar Manufacturing Process...........................1

Extraction...............................................................1

Cane Handling......................................................1

Auxiliary Parts of the Cane Handling Station........2

MILL STATION (EXTRACTION)...............................4

Auxiliary parts of the Mill Station.........................4

Clarification and Purification of Juice.....................7

Equipment Used...................................................7

EVAPORATION........................................................8

Equipment Used...................................................9

Crystallization or Pan Boiling..................................9

OPERATION.........................................................10

EQUIPMENT USED..............................................12

Centrifugation / Purging.......................................13

EQUIPMENT USED..............................................13

REFINERY................................................................14

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Affination..............................................................14

Purification...........................................................15

Sugar house........................................................15

Vacuum pans......................................................15

Sugar drying and storage....................................15

BOILER.................................................................16

PURPOSE OF A BOILER...................................16

TYPES OF BOILER............................................16

Water tube boiler................................................16

Fire tube boiler...................................................16

THREE BASIC ELEMENTS OF A BOILER.....17

ESSENTIAL POSITIONS IN A BOILER STATION.............................................................17

FOREMAN........................................................17

BOILER CONTROL PANEL OPERATOR......17

BOILER WATER TENDER..............................17

FIREMAN..........................................................17

ASHMAN...........................................................17

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UTILITY PERSONNEL....................................17

HEAVY EQUIPMENT OPERATOR................17

FEEDWATER......................................................18

CHEMICALS USED..........................................18

BOILER WATER TREATMENT CONTROL PARAMETERS..................................................18

CHEMICAL PREPARATIONS.........................19

ADJUSTMENT OF CHEMICAL DOSAGES...19

PUMPS USED...................................................20

Deaerator............................................................21

Day Tank............................................................21

FEED WATER FLOW AND DISTRIBUTION 22

BAGASSE CONVEYORS..................................23

Bagasse Elevator................................................23

Main Bagasse Conveyor.....................................23

Surplus Bagasse Conveyor.................................23

Return Bagasse Elevator.....................................24

Travelling Bagasse Conveyor..............................24

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BAGASSE DISTRIBUTION.............................25

DIAGRAM.........................................................25

AIR SUPPLY.......................................................25

FANS AND BLOWERS....................................26

BOILER OPERATION........................................27

FIRING...............................................................27

OPERATION.....................................................27

SHUTDOWN.....................................................27

BOILER PARTS AND ACCESSORIES.............28

Furnace...............................................................28

Economizer.........................................................28

Steam Drum........................................................28

Mud Drum..........................................................28

Superheater Tubes..............................................29

BOILER OUTPUTS AND BY PRODUCTS.......29

STEAM FLOW..................................................29

SCHEMATIC DIAGRAM.................................29

ASH, DUST AND FLUE GAS..........................30

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ASHCONVEYORS............................................30

BOILER FITTINGS AND ACCESSORIES........31

Other Departments..............................................32

Gantry.................................................................32

Power House......................................................32

Pump House.......................................................32

THE SUGAR MILLING OPERATIONS.......................33

INDUSTRY CODE OF PRACTICE..............................33

PART 1. INTRODUCTION.....................................33

This code shall operate from 1 September 1999 and expire on 1 September 2004........................34

PART 2. SAFETY MANAGEMENT SYSTEM...........35

PART 3. MILL HAZARDS.......................................36

References............................................................39

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Sugar Mill• A cane sugar mill is a factory that

processes sugar cane to produce raw or white sugar.

Sugar Cane

Sugarcane refers to any of 6 to 37 species (depending on which taxonomic system is used) of tall perennial grasses of the genus Saccharum (family Poaceae, tribe Andropogoneae).

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Native to warm temperate to tropical regions of Asia, they have stout, jointed, fibrous stalks that are rich in sugar, and measure two to six meters (six to nineteen feet) tall. All sugar cane species interbreed, and the major commercial cultivars are complex hybrids.

Sugar cane products include table sugar, falernum, molasses, rum, cachaça (the national spirit of Brazil), bagasse and ethanol.

Raw Sugar Manufacturing Process

Extraction

Cane HandlingThe cane will be dumped in the feeding carrier.

The feeding carrier will carry the canes and transfer it to the cane carrier. In the feeding carrier there is an equalizer and kicker which are responsible for efficient feeding in the cane carrier. Then the canes will pass through a leveller, two cutters, another leveller and then a kicker. Then it will be shredded

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in the shredder.The shredded cane will be carried by the shredded cane elevator. It will be received by the two pusher rollers. Then, the canes will be pushed to the three rollers where the juice will be extracted. The bagasse will be carried by the intermediate carrier and then to the next mill. There are five mills in the station. There is a maceration box in the 2nd

mill. The mixed juice extracted in 5th mill will be pumped to the 4th mill; the mixed juice in the 4th mill will be pumped to the 3rd mill; the one in the 3rd mill will pumped to the 2nd mill. There is no maceration in the 1st mill. The pure juice in the 1st mill will be mixed with the extracted juice in the 2nd mill and will be pumped to the rotary juice filter.

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Auxiliary Parts of the Cane Handling Station

DUMPER

The dumper will aid the trucks without built in dumpers in dumping their sugar canes on the feeding

carrier.

FEEDING CARRIER

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It transports the dumped cane to the equalizer, kicker and into the cane carrier. It is powered by a motor. Its speed is manually controlled by the operator.

EQUALIZER

It controls the level of the canes and it will make sure that the canes are evenly distributed. The rotation of the equalizer is against the

direction of the feeding carrier. This is driven by a motor.

FEEDING CARRIER KICKER

It pushes the canes from the feeding carrier to the cane

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carrier. Its rotation is along with the direction of the feeding carrier. This is driven by a motor.

CANE CARRIER

It carries and transports the cane coming from the feeding carrier into the shredder.

CANE CUTTER

It cuts the cane in the cane carrier. This is powered by a motor.

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CANE SHREDDER

Its function is to pulverize the canes. It is composed of 88 swing type hammers properly arranged into 8 rows. Each row has 11

hammers. It is responsible in pulverizing the cane. Because of too high rpm, it can produce shredded canes. It is driven by a 800 KW turbine.

MILL STATION (EXTRACTION)

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The mill station utilizes the mill system; it has a target milling capacity. The mills use proliferated mill rollers for better extraction of juice. Maceration and imbibition is applied during milling to attain efficient extraction of juice with a target of mixed juice % cane of 108%.

Centralize lubrication system is being used by the mill station, it uses a food grade grease for lubrication, these grease will not contaminate the milled juice when mixed.

Auxiliary parts of the Mill Station

SHREDDED CANE ELEVATOR

It carries the shredded cane to the 1st mill extraction. It is an elevator that will transport the canes to the first mill. This is powered by a

motor.

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PUSHER ROLLER

It receives the shredded cane from the carrier and pushes it to the feed roller.

MILL ROLLERThere are three mill rollers - top

roller, feed roller and the discharge roller. The top roller receives the shredded cane together with the feed

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roller. They squeeze the cane and extract the juice. After squeezing, the top roller pushes the cane to the discharge roller. The discharge roller pushes the cane to the intermediate carrier. This roller is attached to a turning bearing. A food grade lubricant is use in the continuous lubrication of the turning bearing.

INTERMEDIATE CARRIER

The intermediate carrier is a rake type of elevator since it uses rake bars in carrying the bagasse. Its function is

to transport the squeezed cane to the next mill. It is powered by a motor.

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ROTARY JUICE FILTER

It filters and separates the bagasse from the final juice. The screened juice will go into the

screened juice tank and the bagasse will go back in the 2nd mill.

SCREW OR SPIRAL CONVEYOR

It transfers the bagasse from the strainer and dumps it to mill #2.

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SCREENED JUICE TANK

The final screened juice will be collected by this tank and will be

pumped to the mixed juice tank of the process department.

MACERATION BOXOnly the first mill has no maceration

box. The maceration box provides enough water for efficient extraction of juice. In the fifth mill, condensate water mixed with

raw water is mixed with the bagasse for final extraction and so that the standard moisture of the bagasse will be reached.

TOP CAPIt has a piston inside which is responsible in

applying pressure to the top roll of the mill for better juice extraction.

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MILL TURBINE

The mill department uses single stage, multiple blades impulse type turbines to drive the

mills, shredder, and cane cutter #2 exhaust steams coming out from these turbines will be collected in the low pressure header and will be utilized by the process department.

Mill Turbine Auxiliary Parts

Governor

The governor attached on the turbines of the mill station is a PTD typeof governor. The

governor is responsible in varying the rpm of the turbines.

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Tripping DeviceIt is responsible in closing the

passage of steam to the rotors of the turbine when the pressure of the inlet steam exceeded the

standard value or when the oil supply is being cut off. It serves as a safety device for the turbine so that the rotors of the turbine will not be destroyed. \

Expansion Joint

It serves as a shock absorber when the steam enters the inlet pipe so that the inlet pipe will not be

destroyed.

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Lube oil pumpSupplies oil to the bearings of the turbine and

the gear reduction to prevent wearing and damage of the bearings.

Clarification and Purification of Juice

Prior to clarification, the juice will be scaled and pre-heated. The Platform Weigh Bridge is used in scaling for accounting purposes. The juice will be transferred to the mixed juice tank if its weight reaches 6000 kilograms. The juice from mills is acidic, turbid and dark green, thus cold liming must be done. Cold liming is a pre-treatment of pH that targets a value of 6.4. Then the juice will pass through three 10-pass vertical heaters and six 12-pass horizontal heaters. The heaters utilize the vapor

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temperature to heat up the juice in order to kill bacteria. The target temperature is 105 C. ⁰

Lime and heat are considered as clarifying agents. This is the reason why the juice must undergo hot liming.

Flocculent is the main chemical which is responsible in juice clarification. This chemical is dissolved in water and is being mixed with the juice.

There are two types of clarifiers used in the company – rapidorr and the trayless. The rapidorr has four compartments that will trap the mud while the trayless applies the settling method.

The outputs of this process are clarified juice and muddy juice. The clarified juice will be screened before evaporation to make sure that there are no impurities present. The muddy juice will be filtered to recover the remaining clear juice. The muddy juice passes through the rotary vacuum filter, where the filtrate juice is recovered and will be pumped back to the mixed juice tank. The waste

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product is called filter cakes which could be used by the planters as fertilizer.

Equipment Used

Mixed Juice Tank  

The capacity of the tank is 60 m3. It is rectangular in shape with slope bottom made of stainless steel.

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Juice Heaters

They have holes inside where juice passes through. The vertical heaters have ten(10) passes while the horizontal heaters have twelve(12)

passes which aids in heat transfer. The more number of passes the better heat transfer since there is longer time for the juice to absorb the heat from the vapor. The heaters used are non-contacting.

ClarifierIt has a stirrer which is driven by a motor. The motor is mounted on top.

Rotary Vacuum Filter (RVF)

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This has a vacuum pump which is responsible in generating vacuum inside the filter. The mud and other impurities will stick into the outside part of the filter and will be scraped. There is a horizontal screw conveyor below the scraper which transfers the filter cake into the belt conveyor.

EVAPORATIONClarified juice contains natural water from the

sugar cane and the water used in the process of imbibition or maceration. Through evaporation, major portion of the water content of the juice will be removed to produce syrup. Evaporation is the process of removing water from the juice using steam as the source. The clarified juice from the clarified juice tank has to undergo evaporation to evaporate its water content which is about 85% - 90 %.

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The vapor produced has a pressure of 0.8 to 1.4 kPa and a temperature of 104-112 ⁰C.

The evaporation process employs quadruple effect meaning the juice is heated four times to evaporate its water content and to produce highly viscous syrup with the desired brix. Evaporator cells are arranged in series in which he succeeding cell has a higher vacuum and boils at a lower temperature.

Exhaust steam from the boiler will be injected to the first cell which would apparently heat the clarified juice from the clarified juice tank up to 112⁰C maximum for first stage of evaporation. The vapor produced from the first cell shall be used as the heating medium of cells 2A and 2B, horizontal heaters and vacuum pans. Then the second stage of evaporation in cells 2A and 2B follows using the vapor from the first cell with a maximum heating temperature of 102⁰C.

The syrup temperature is strictly monitored since it would affect the target brix and

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concentration of the syrup. If syrup temperature exceeds the standard temperature, some of the syrup will evaporate and will mix with the vapor. This would cause a great loss of the company.

Condensates from evaporator cells 1, 2A and 2B will be used as boiler feed water and condensates from evaporator cells 3A, 3B and 4 will be delivered to hot water receiving tank for process use.

Cleaning or soda boiling is done every two weeks.

Equipment Used

EvaporatorAn evaporator is made up of two closed spaces, separated from one another by thin metal walls in the form of tubs called the heating surface. Steam enters in one of these spaces at a certain

temperature and pressure on which it condenses and

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thus giving up latent heat. In the other space the juice absorbs the releases heat, thus evaporation of water occurs.

Crystallization or Pan Boiling

The process of crystallization involves the boiling of syrup which takes place in single effect vacuum pans. In this process, it is very important to know the syrup concentration at all times in order to attain the desired brix and purity of the sugar. The purpose of evaporation is to create the desired grain size of the sugar. Graining is initiated by adding sugar slurry which is a mixture of alcohol and refined sugar.

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The entire process starts in boiling of syrup in Pan #7 called the raw vacuum pan. After the syrup reaches its desired brix, it will be transferred through the cutting line to either Pan #8 or Pan #9, also known as high grade vacuum pans, to maximize its brix. The feeding of syrup in the high grade vacuum pans continues until it attains the desired brix and will be discharge and stored in A-massecuite receiver located below the vacuum pans.

Raw sugar and A-molasses are the outputs of A-massecuite. A-molasses will be used by vacuum pans #1, #2and #3 and will be mixed with C-magma, a by-product of C-massecuite coming from vacuum pans #4, #5 and #6, to produce B-massecuite. The products of B-massecuite are B-magma and B-molasses in which the B-magma will be used to feed Pan #7 and will be mixed with syrup for pre brixing while the B-molasses along with C-seed will be feed to Pans #4, #5, and #6 to produce C-massecuite. The final molasses also known as blackstrap, a product of C-massecuite will be pumped and weighed to final molasses weigh scale for accounting purposes

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and it will served as a base for cattle feed, production of alcohol, yeast and other products.

It is required that the temperature of the vacuum pans must not exceed 70⁰C. To have a lower temperature, the volume of C-massecuite strike must be reduced to 32m3 (graining of 13m3 + B-molasses of 19m3), and it shall have a purity of 55. For B-massecuite, the strike will be reduced to 34m3 (C-magma of 15m3 + A-molasses of 19m3), and must have a purity of 70-72.

OPERATION

Preparatory Activities before Operation

Material

• Prepare sugar supply

• Check that condenser water, vacuum pump sealing water clean fresh water are available.

• Machine Preparation and other Activities

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• Check internal and close manholes, drain lines of vessels and tankages

 

Start-up Procedure

Vacuum Pumps and Pan Start – Up

• Generate Vacuum for A-Seed Vacuum Pan

• Open vacuum pump sealing water turn on vacuum pump for vacuum pump in use.

• Open steam ejector valves, steam ejector water valve and pan condenser water valve.

• Wait till vacuum is generated.

Operation Cycle Starts

A-Seed Graining using Syrup

• Open syrup feeding valve and close valve until first desire graining volume is reached. Let boil/saturate the syrup.

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• Add 250 mL sugar slurry by pouring it to slurry pot and open slurry valve. Close the valve when slurry is completely injected into the pan.

• Develop slurry grains

• Gradually feed syrup until it reaches the final graining volume

• Coordinate with pan man II to transfer A-seed from A-seed pan to production pan for A – Massecuite boiling.

 

C- Seed Graining

• Generate vacuum for low grade pan in use.

• Open syrup feed valve until desired volume is reached.

• Boil and saturate the syrup.

• Add 1000 mL of sugar slurry by pouring it out to the slurry pot and open slurry pot valve. Close the valve when the slurry is completely injected into the pan.

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• Gradually feed A-Molasses until reaching the final graining volume. Take graining sample.

• Close steam valve.

• Release vacuum breaker.

• Open cutting valve.

C- Massecuite Production

• Open cutting valve of low grade vacuum pan

• Draw one cut (13 m3) of C-Seed from vacuum pan

• Close cutting valve

• Open steam valve

• Gradually feed A-Molasses until reaching final strike volume. Maintain the desire brix in the process of boiling up volume by following close-boiling system

Dropping C-Massecuite Strike

• Close inlet steam valve

• Close condenser water valve

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• Close steam ejector valves and jet condenser valve

• Close booster valve

• Release vacuum breaker

• Ring the bell to alarm crystallizer attendant of strike to be dropped

• Open vacuum pan discharge valve when vacuum is already below 20 cmHg

• Take massecuite sample and label as C-strike number, give the strike volume, date and time dropped.

• Send sample to laboratory

• Steam up calandria tubes after discharging all the massecuite

• Close steaming valve and pan discharge valve

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EQUIPMENT USED

Vacuum PanThe vacuum pressure and temperature are strictly monitored since it would greatly affect sugar crystallization. This equipment used either vapor or steam in boiling. It has a condenser at the back which

would help in regulating the pressure and temperature of the fan. The opening of the condenser is dependent on the vacuum pressure and temperature inside the pan. The opening will be increased if the vacuum pressure and temperature exceeds the standard value.

The condenser is cooled by the injected water. There are baffle plates inside the condenser which will direct the motion of the steam/vapor. The temperature of the water is very important so that the

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condenser can successfully maintain the require pressure and temperature of the pan.

Massecuite Receiver This equipment serves as temporary

container for the massecuite. It has a stirrer inside. At the bottom of it, there is a manual opening compose of gear train

with a rack and pinion. Force is applied in the wheels to move the gear trains and will cause an upward motion of the rack. The rack is mounted to the shutter of the receiver and due to the upward motion of the rack, massecuite can pass through. This equipment also has a ribbon that stirs the massecuite.

Crystallizer This equipment is driven by a chain and

powered by a motor. This is used for the low grade massecuite prior to purging.This equipment helps in developing the sugar crystals of massecuite B and C.

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There are two types of crystallizers used in the process – the horizontal and the vertical. The horizontal is used for the B- Massecuite while the vertical was used for C-Massecuite.

Centrifugation / PurgingCentrifugation is a process involving centrifugal

force to separate mixtures. Sugar crystals in the massecuite are separated from the molasses due to the centrifugal force exerted by the centrifugal machines.

Massecuites from massecuite receivers will be pumped to the mixers above the baskets and will be fed into revolving machines called centrifugal machines. A mixer is a container with revolving arms bolted to a square shaft to prevent the crystals from settling. Each grade (low and high grade) massecuite centrifugal machines has its own feed mixer. A centrifugal machine is consists of a drum or basket suspended on a spindle that revolves within a metal casing which catches the molasses. The drum or basket has perforated vertical sides

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lined with a brass wire backing screen about 10 meshes per inch. Inside of which is a perforated sheet brass known as lining. The backing screen permits more rapid drainage of the molasses.

The machine revolves through the use of v-belts connected to the motor that revolves at a speed ranging from 1000-2000 revolutions per minute. The perforated lining retains the sugar crystals which maybe wash if desired while the molasses passes through the lining due to the centrifugal force exerted on the basket.

When the machine is set in motion, the massecuite will be fed on the machine and the sugar-molasses mixture moves away from the center and rises due to the applied centrifugal force. The massecuite is distributed over the perforated lining and the molasses will be expelled and the sugar crystals will be retained. Sugar crystals may be further purge by spraying the wall of the basket-containing-sugar with a measured amount of water. The purging continues until the sugar crystals are practically free

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from molasses. Then, the sugar is now ready to be discharge by opening the discharge valve or sometimes called core which is located at the bottom of the machine.

Purging of A-massecuite on high grade centrifugal machines yields raw sugar and A-molasses. B-massecuite will be purge on the low grade baskets 1, 2, 3 and yields B-magma and B-molasses. C-massecuite will be purge in baskets 4, 5, 6, 7, 8, and 9 and its outputs are final molasses and C-magma.

EQUIPMENT USED

Feed Mixer There are two feed mixers in the process, one is

used for B and C Massecuite which is driven by an 11kW motor and the other one is used for A-Massecuite which is driven by a 3.7 kW motor. It holds the massecuite that will be fed to the centrifugal machines. It has a paddle that stris the massecuite to prevent solidification.

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Low Grade Centrifugal Machine

It consists of a drum or basket suspended on a spindle that revolves within a metal casing which catches the molasses. The drum or basket has perforated vertical sides lined with a brass wire backing screen about 10 meshes per inch. Inside of which is a perforated sheet brass known as lining. The backing screen permits more rapid drainage of the molasses. The machine revolves through the use of v-belts connected to the motor that revolves at a speed ranging from 1000-2000 revolutions per minute. The perforated lining retains the sugar crystals which maybe wash if desired while the molasses passes through the lining due to the centrifugal force exerted on the basket.

High Grade Centrifugal Machine

Motor: 100 kW RPM: 1200

This is operated by batch. It has a pneumatic discharger with a cylinder and scrapper. The

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cylinder serves as the container of the compressed air and the scrapper removes the sugar that stick in the basket. The machine is attached with a basket valve lifter which will direct the opening of the shutter below the basket. The amount of load is set by the operator. Unlike in low grade basket, the form od the basket of this machine is cylindrical.

Screw Conveyor, Bucket Elevator, and Inclined Belt Conveyor

The screw conveyor is powered by a 3.7 kW motor. It transfers the sugar into the bucket elevator. The bucket elevator which is powered by a 5.5 kW motor carries the sugar and dumps it to the belt conveyor. Finally, the belt conveyor transports the sugar to the warehouse.

Mingler This equipment is used in receiving the sugar

from the low grade centrifugals. Water is added to the sugar and the mixture is called magma.

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REFINERY

A sugar refinery is a factory which refines raw sugar.

Many cane sugar mills produce raw sugar, i.e. sugar with more colour and therefore more impurities than the white sugar which is normally consumed in households and used as an ingredient in soft drinks, cookies and so forth. Raw sugar is either processed into white sugar in local refinieries or sold to the local industry and consumers or it is exported and further processed in the country of destination.

While cane sugar does not strictly need refining, beet sugar is almost always refined to remove the strong, almost always unwanted, taste of beets from it.

Affination

The raw sugar is stored in large warehouses and then transported into the sugar refinery by means of transport belts. In the

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traditional refining process, the raw sugar is first mixed with heavy syrup and centrifuged to wash away the outer coating of the raw sugar crystals, which is less pure than the crystal interior. Many sugar refineries today buy high pol sugar and can do without the affination process.

Purification

The remaining sugar is then dissolved to make a syrup (about 70 percent by weight solids), which is clarified by the addition of phosphoric acid and calcium hydroxide that combine to precipitate calcium phosphate. The calcium phosphate particles entrap some impurities and absorb others, and then float to the top of the tank, where they are skimmed off.

After any remaining solids are filtered out, the clarified syrup is decolorized by filtration through a bed of activated carbon.

Sugar house

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Vacuum pans

The purified syrup is then concentrated to supersaturation and repeatedly crystallized under

vacuum to produce white refined sugar. As in a sugar mill, the sugar crystals are separated from the mother liquor by centrifuging. To produce granulated sugar, in which the individual sugar grains do not clump together, sugar must be dried.

Continuous sugar centrifugal for recovery products

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Sugar drying and storage

Drying is accomplished first by drying the sugar in a hot rotary dryer, and then by blowing cool air through it for several days in so-called conditioning silos. The finished product is stored in large concrete or steel silos. It is shipped in bulk, big bags or 25 - 50 kg bags to industrial customers or packed in consumer-size packages to retailers.

The dried sugar must be handled with caution, as sugar dust explosions are possible. A sugar dust explosion which led to 13 fatalities was the 2008 Georgia sugar refinery explosion in Port Wentworth, GA.

BOILER

PURPOSE OF A BOILERThe boiler is the heart of the industrial plant, it

generates and supplies steam required by the operation. It supplies steam to the mill department, refinery, power house and process department.

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TYPES OF BOILER

Water tube boilerIn this type of boiler, the water tubes are

arranged inside a furnace in a number of possible configurations: often the water tubes connect large drums, the lower ones containing water and the upper ones, steam and water; in other cases, such as a mono tube boiler, water is circulated by a pump through a succession of coils. This type generally gives high steam production rates, but less storage capacity than the above. Water tube boilers can be designed to exploit any heat source and are generally preferred in high pressure applications since the high pressure water/steam is contained within small diameter pipes which can withstand the pressure with a thinner wall.

Fire tube boilerThis is the type of boiler used in nearly all steam

locomotives. The heat source is inside a furnace or firebox that has to be kept permanently surrounded

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by the water in order to maintain the temperature of the heating surface just below boiling point. The furnace can be situated at one end of a fire-tube which lengthens the path of the hot gases, thus augmenting the heating surface which can be further increased by making the gases reverse direction through a second parallel tube or a bundle of multiple tubes (two-pass or return flue boiler); alternatively the gases may be taken along the sides and then beneath the boiler through flues (3-pass boiler). In the case of a locomotive-type boiler, a boiler barrel extends from the firebox and the hot gases pass through a bundle of fire tubes inside the barrel which greatly increase the heating surface compared to a single tube and further improve heat transfer. Fire-tube boilers usually have a comparatively low rate of steam production, but high steam storage capacity. Fire-tube boilers mostly burn solid fuels, but are readily adaptable to those of the liquid or gas variety.

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THREE BASIC ELEMENTS OF A BOILERThe three basic elements of a boiler are water,

fuel (bagasse), and air. These three elements are essential in order to obtain the optimum efficiency of the boiler.

ESSENTIAL POSITIONS IN A BOILER STATION

FOREMAN The foreman monitors all employees and makes

sure that works are properly done. He is responsible in task distribution.

BOILER CONTROL PANEL OPERATORThe panel operator is the one that monitors the

performance of the boilers. He will be responsible in controlling the percent of openings of the air, feeders, and feed water in order to correct abnormal activities of the boilers. He is the one regulating the amount of steam supplied to the process station. He is the one that will give notice to other personnel in case there is a problem like low steam.

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BOILER WATER TENDERThe water tender is responsible for boiler’s

water treatment. He is also responsible in starting the turbine of the induce draft fan.

FIREMANThe fireman monitors the combustion. He is the

one assigned in deashing and in monitoring and unclogging the bagasse feeders.

ASHMANThe ashman is responsible in disposing the

ashes.

UTILITY PERSONNELThe utility personnel maintain the cleanliness of

the boiler station.

HEAVY EQUIPMENT OPERATORThe heavy equipment operator loads the return

conveyor with bagasse during back feeding.

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FEEDWATER

CHEMICALS USED

DICLEAN B-562Controls residual phosphate and prevents

hardness.

DICLEAN B-901Anti foaming

OXYNON S-340FGAnti corrosion

COSTIC SODAControls the pH level of the boiler feedwater.

BOILER WATER TREATMENT CONTROL PARAMETERS

PARAMETERS

UNITS

BOILER NO. 1 AND 2(18 – 20 kgsf/cm2)

BOILER NO. 3(20 – 40 kgsf/cm2)

FEED WAT

BOILER

FEED WAT

BOILER

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ER WATER

ER WATER

pH - 8.0 – 9.5

10.5 – 11.5

8.0 – 9.5

10.0 – 11.0

ELECTRICAL CONDUCTIVITY

µS/cm - 3,000 - 1,000

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 0

CALCIUM HARDNESS

mg CaCO3/L

0 0 0 0

SILICA mgSiO2/L

- - - 50 max

RESIDUAL SULFITE

mg/L - 10 – 20

- 5 – 10

PHOSPHAT mg - 20 – - 5 - 15

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E ION PO43-/L 40

CHLORIDE ION

mg Cl+/L

- 150 max

- 100 max

TOTAL IRON

mg Fe/L

0.1 max

- 0.1 max

-

CHEMICAL PREPARATIONS

DOSING POINTS

BOILERS 1 AND 2

BOILER 3

CHEMICAL DILLUTION

CHEMICAL DILLUTION

HIGH PRESSURE LINE CHEMICAL TANK

DICLEAN B-562 = 1 KG.DICLEAN B-901 = 1 KG.WATER = 150

DICLEAN B-562 = 1.3 KG.DICLEAN B-901 = 1.3 KG.WATER = 100

LOW PRESSURE LINE CHEMICAL

OXYNON S-340FG = 900 GRAMSWATER = 100

OXYNON S-340FG = 1.2 KG.WATER = 100

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TANK

ADJUSTMENT OF CHEMICAL DOSAGES1.Incase Calcium Hardness in Feedwater

exceeds normal 0 ppm readingAdd additional Diclean B-562 if ppm of calcium hardness exceeds 1 ppm

HARDNESS KG. DICLEAN B-562

BOILERS 1 AND 2

BOILER 3

2 ppm 1 1.23 ppm 2 2.44 ppm 3 3.65 ppm 4 4.86 ppm 5 67 ppm 6 7.28 ppm 7 8.49 ppm 8 9.610 ppm 9 10.811 ppm 10 1212 ppm 11 13.2

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13 ppm 12 14.4

2.In case Residual Phosphate (RP) in Boiler water in Boiler water is below normal (10-30 ppm)Add Additional Diclean B-562 per shift as follows

RESIDUAL PHOSPHATE

5 ppmBOILERS 1 AND 2

BOILER 3

Kg. Diclean B-562

3.5 4

3.In case silica in Feedwater exceeds 50 ppmAdd additional Diclean B-901 per shift as follows

SILICA IN FEEDWATER

50 PPM 100 PPM

150 PPM

Kg. Diclean B-901

0.6 1.6 2.5

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4.In case of EntrainmentAdd additional B-901 per shift until entrainment is gone.

BOILER 1 AND 2

BOILER 3

Kg. Diclean B-901

7 9

NOTES:a. When blowdown water becomes murky and

turbid, there is a leakage of hardness components in the feedwater.

b.Overdosage of chemicals will slow the following in laboratory analyses.1.Diclean B-562 overdose. Residual

Phosphate is over 30 ppm.2.Oxynon S-340FG overdose. Residual

sulphite is over 20 ppm.

Blowdown and Diclean B-562 Control

BOILER WATER QUALITY

KGS. DICLEAN

BLOWDOWN

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B-562High E-Condition

High Phosphate

maintain increase

Low E-Condition

Low Phosphate

maintain decrease

Low E-Condition

High Phosphate

decrease decrease

High E-Condition

Low Phosphate

increase increase

High E-Condition

Correct Phosphate

maintain increase

Low E-Condition

Correct Phosphate

maintain decrease

Correct E-Condition

High Phosphate

decrease maintain

Correct E-Condition

Low Phosphate

increase maintain

PUMPS USED

Lift PumpA centrifugal pump is a

rotodynamic pump that uses a rotating impeller to increase the

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pressure of a fluid. Centrifugal pumps are commonly used to move liquids through piping. The fluid enters the pump impeller along or near to the rotating axis and is accelerated by the impeller, flowing radially outward into a diffuser or volute chamber (casing), from where it exits into the downstream piping. Centrifugal pumps are used for large discharge through smaller heads.

Feedwater Pump (Multistage Centrifugal Pump)

A centrifugal pump containing two or more impellers is called a multistage centrifugal pump. The impellers may be

mounted on the same shaft or on different shafts.

If we need higher pressure at the outlet we can connect impellers in series.If we need a higher flow output we can connect impellers in parallel.All energy added to the fluid comes from the power of the electric or other motor force driving the impeller.

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Chemical Pump (Diaphragm Pump)A diaphragm pump is a

positive displacement pump that uses a combination of the reciprocating action of a rubber, thermoplastic or Teflon diaphragm

and suitable non-return check valves to pump a fluid. Sometimes this type of pump is also called a membrane pump

DeaeratorIt supplies hot water to the

boiler; condensate from process is heated at a temperature of about 110 oC by the steam from the

boiler. The deaerator is also responsible in removing the excess oxygen and other gases dissolved in water in order to avoid corrosion in the surface of tubes.

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Day TankIt supplies water to the

deaerator through a pump in case the water level of the deaerator is very low.

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FEED WATER FLOW AND DISTRIBUTION

DIAGRAM

The condensate from the process and refinery serves as the feedwater of the boiler. It will be stored in the condensate tank. The condensate having a

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temperature below 100⁰C will be pumped to the deaerator and day tanks. The deaerator is used for preheating and removing non-condensable gases. If the water level of the deaerator is low, condensate from the day tank will be pumped to it using lift pumps.

From the deaerator, the feedwater goes to the low pressure header (suction header). It is also in this header where the diluted chemical is pumped using gear pump.

Then, the feedwater goes to the high pressure header (discharge header) using the feedwater pump, a multistage centrifugal pump suitable for high pressure header. The diluted chemical in high pressure chemical tank is pumped in this header. The boilers are equipped with economizer which will reheat the feedwater to increase the boiler efficiency. The economizer uses the flue gas from the chamber as a heat source. After which, the feedwater goes to the steam drum. It is required that the water level of the steam drum is or below the mid-level.

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BAGASSE CONVEYORS

Bagasse Elevator

It carries the bagasse from the 5th mill to the main bagasse conveyor.

Main Bagasse Conveyor

It carries the bagasse to the feeders of the boilers.

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Surplus Bagasse ConveyorIt carries the excess bagasse and

transfers it to the travelling conveyor for dumping in the

warehouse. It has a shutter controlled by the operator which will serve as an opening for the return bagasse conveyor.

Return Bagasse Elevator

It carries the bagasse during back feeding and transfers the bagasse through a chute to the main bagasse conveyor.

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Travelling Bagasse Conveyor

It transports the excess bagasse coming from the surplus conveyor to the bagasse

warehouse.

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BAGASSE DISTRIBUTION

DIAGRAM

AIR SUPPLYIt is important that there must be air supply and

the flue gas must be removed in the combustion chamber. The forced draft fan supplies the air needed for good combustion and the induced draft

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fan removes the flue gas and discharge it to the chimney.

The ambient air that enters the forced draft fan passes through an air preheater. It is a device designed to preheat the combustion air used in a fuel burning furnace for the purpose of increasing the thermal efficiency of the furnace. After passing the preheater, the heated air is distributed to the secondary forced draft fan, bagasse distribution fan and undergrate damper.

The secondary forced draft fan blows air on the sides of the chamber whereas the bagasse distribution fan blows the bagasse in the bagasse feeders for even distribution of the fuel.

FANS AND BLOWERS

Force Draft Fan

Collects fresh air and passes the air to the air heater. The heated air will be used by the secondary

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force draft fan to aid combustion and by the bagasse distribution fan.

Bagasse Distribution Fan

It blows hot air to help the feeders in spreadingand distributing the bagasse to the

furnace.

Secondary Force Draft Fan

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It aids in burning the bagasse by blowing hot air in to the surface of the furnace.

Induced Draft Fan

It absorbs flue gas from the boiler.

AIRHEATER

An air preheater (APH) is a general term to describe any device designed to

68

preheat the combustion air used in a fuel-burning furnace for the purpose of increasing the thermal efficiency of the furnace.

BOILER OPERATION

FIRINGBefore starting the firing of the boiler, the three

basic elements namely the water, air and fuel must be present. Superheater drains must be first opened to remove condensates from the superheater line. Check the water level of the drum. The boiler should have a starting drum level of -50 mmH2O. If the water level of the drum exceeds -50 mm H2O, the bottom blowdown is needed. Secure that there is enough fuel (bagasse) inside the furnace. If it isn’t enough, the feeders should be run slowly to supply enough bagasse inside the furnace, wait until the pressure reaches 10 kg/cm2 before turning the feeders on. All the fans should be run to aid combustion. If the boiler starts to have the load of

69

evaporation, that’s the time that the feedwater pump will be opened to supply water into the boiler. When the pressure reaches 15 kg/cm2 and the temperature

reaches 250⁰C and above the boiler is ready for cut-in.

OPERATIONDuring operation the water tender is in charge to

monitor the temperature of the bearings of the IDF. He is also on charge in adding the right amount of chemicals in the feedwater to ensure a good quality of feedwater. Deashing is done by the every 4 hours. The utility personnel maintain the cleanliness in the boiler area. The foreman monitors all the boiler personnel and assures that all works are properly and safely done.

SHUTDOWNFirst thing to do in shutting down the boiler is

turned-off all the forms in order to stop the combustion. Feedwater pump must be turned off to stop the supply of water. Then superheater drains

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should be opened. Deashing follows and at the same time the boiler steam supply valve must be closed.

BOILER PARTS AND ACCESSORIES

Furnace

It is the primary area of combustion; it is where the bagasse is being burned to produce flue gas.

Economizer

It heats up the water from the deaerator and transfers it to the steam drum. It is used for boiler

economy.

71

Steam Drum

Collects Steam generated by the boiler. It must be half filled with water to prevent carry over that might destroy

the turbines.

Mud Drum

It is where solid particles and other water impurities settle. It looks like the steam

72

drum but it is located at the bottom of the steam drum.

Superheater TubesSuperheater tubes superheat the steam coming

from the steam drum. The boiler uses pendant type of superheater tubes.

73

BOILER OUTPUTS AND BY PRODUCTS

STEAM FLOW

SCHEMATIC DIAGRAM

74

ASH, DUST AND FLUE GAS

DUST COLLECTOR

It separates the flue gas absorbed by the IDF from the dust with the use of cyclones. The dust will fall on

the chutes and will be collected by the dust conveyor.

Chimney

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It discharges flue gas absorbed by the IDF into the atmosphere.

ASHCONVEYORS

DEASHING CONVEYOR

Collects and carries the ashes as a result of deashing.

AIR HEATER CONVEYOR

Collects and carries the ashes coming from the air heater.

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DUST CONVEYOR

Collects and carries the dust that has fallen from the dust separator.

ASH AND DUST REMOVAL CONVEYOR

Collects all the ashes and dust collected by the three conveyors and place it in a large

chute. The ashes will be collected by dump trucks for proper disposal.

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BOILER FITTINGS AND ACCESSORIESSafety valve: It is used to relieve pressure and prevent possible explosion of a boiler.

Water level indicators: They show the operator the level of fluid in the boiler, also known as a sight glass, water gauge or water column is provided.

Bottom blowdown valves: They provide a means for removing solid particulates that condense and lie on the bottom of a boiler. As the name implies, this valve is usually located directly on the bottom of the boiler, and is occasionally opened to use the pressure in the boiler to push these particulates out.

Continuous blowdown valve: This allows a small quantity of water to escape continuously. Its purpose is to prevent the water in the boiler becoming saturated with dissolved salts. Saturation would lead to foaming and cause water droplets to be carried over with the steam - a condition known as priming. Blowdown is also often used to monitor the chemistry of the boiler water.

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Flash Tank: High pressure blowdown enters this vessel where the steam can 'flash' safely and be used in a low-pressure system or be vented to atmosphere while the ambient pressure blowdown flows to drain.

Automatic Blowdown/Continuous Heat Recovery System: This system allows the boiler to blowdown only when makeup water is flowing to the boiler, thereby transferring the maximum amount of heat possible from the blowdown to the makeup water. No flash tank is generally needed as the blowdown discharged is close to the temperature of the makeup water.

Hand holes: They are steel plates installed in openings in "header" to allow for inspections & installation of tubes and inspection of internal surfaces.

Steam drum internals: A series of screen, scrubber & cans (cyclone separators).

Surface blowdown line: It provides a means for removing foam or other lightweight non-condensible

79

substances that tend to float on top of the water inside the boiler.

Feedwatercheck valve or clack valve: A non-return stop valve in the feedwater line. This may be fitted to the side of the boiler, just below the water level, or to the top of the boiler.

Desuperheater tubes or bundles: A series of tubes or bundles of tubes in the water drum or the steam drum designed to cool superheated steam. Thus is to supply auxiliary equipment that does not need, or may be damaged by, dry steam.

Chemical injection line: A connection to add chemicals for controlling feedwaterpH.

Other Departments

GantryIt is responsible in hauling the canes. Its

temporarily stored the buckets of canes.

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Power HouseIt supplies enough power for the whole plant. It

is responsible in the production of electrical power.

Pump House It is in charge in monitoring the pumps for

efficient water circulation.

Cooling Tower

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The type of cooling tower used is induced draft

counter flow. Its capacity is 600 m3/hr.

THE SUGAR MILLING OPERATIONS

INDUSTRY CODE OF PRACTICE

PART 1. INTRODUCTION

82

1.1 ObjectiveThe objective of the Sugar Milling Operations Industry Code of Practice is to provide a safer workingenvironment for all who work in sugar mills by providing practical advice about the management of risks arisingfrom all activities associated with the sugar milling industry in Queensland.

1.2 How to use this Code

The Sugar Milling Operations Industry Code of Practice (Sugar Milling Safety Code) has been written to assist mills to meet their obligations with respect to workplace health and safety, and to assist generally with the provision and maintenance of a safe working environment in Queensland sugar mills.

The Code does not attempt to provide a comprehensive step by step guide to ensure workplace health and safety. Although attempts have been made to keep the code as relevant as possible, it is acknowledged that the individual circumstances

83

of companies will continue to dictate the type of preventative or control measures which are implemented to meet management’s obligations under the workplace health and safety legislation. This Code provides a useful guide to the particular risks which sugar mill management and workers need to be aware of, and to methods of addressing those risks.

Due to the variety of situations encountered at mills it is difficult to be prescriptive in an industry widedocument. For this reason care has been taken to limit prescriptive or directive language to situations where the requirement stems from a direct legal obligation under the Act or a Regulation. For the purpose of this code such prescriptive provisions shall be indicated by the terms “must” or “shall” and by no other terms.

Conversely, where non-prescriptive language such as “may” or “should” is used, or if any other form of language apart from “must” or “shall” is used, then the provision is intended to be a recommendation or suggestion, which may be

84

implemented at discretion, based on an assessment of its suitability at the particular workplace.

1.3 DisclaimerThe contents of this Sugar Milling Safety Code

do not constitute legal advice and should not be relied upon as such. Formal legal advice should be sought for appropriate matters.

1.4 Expiry Date

This code shall operate from 1 September 1999 and expire on 1 September 2004

2 Legislation2.1 Statute LawThe statute law that governs workplace health and safety in Queensland is the Workplace Health and

Safety Act1995 as amended (the Act). Compliance with the Act is mandatory and schedule 1 of the Act sets out the list ofoffences and penalties for proven non-compliance.

85

2.2 RegulationA regulation is subordinate legislation. Section 38 of the Act covers regulations that include matters previouslycovered under compliance standards. Section 38 states:38(1) The Governor in Council may make regulations under this Act.(2) A regulation may-(a) deal with matters of an administrative nature; or(b) prohibit exposure to risk; or(c) prescribe ways to prevent or minimise exposure to risk.(3) A regulation may-(a) prescribe offences for a breach of a regulation; and(b) fix a maximum penalty of not more than 40 penalty units for the breach.(4) A regulation may declare something to be a workplace health and safety obligation imposed on aperson for this Act.

2.3 Advisory StandardsThe making of advisory standards is covered under section 41 of the Act. Section 41 states:

86

41.(1) The Minister may make-(a) advisory standards that state ways to manage exposure to risks common to industry; and(b) industry codes of practice that state ways to manage exposure to risks identified by a part ofindustry as typical in the part of industry.(1A) The standard or code of practice must include a provision that states the standard or code ofpractice expires 5 years after its commencement.(2) The Minister must notify the making of an advisory standard or industry code of practice.(3) The Minister must ensure that a copy of each advisory standard or code of practice and anydocument applied, adopted or incorporated by the standard or code of practice is made available forinspection, without charge, during normal business hours at each department office dealing withworkplace health and safety.(4) A notice mentioned in subsection (2) is subordinate legislation.

2.4 Industry codes of practiceIndustry codes of practice were introduced under the Workplace Health and Safety Amendment Act 1997. An

87

industry code of practice which is made by the Minister under section 41 of the Workplace Health and

Safety Act1995 (the Act) has the same standing as an advisory standard made under section 41 of the Act. This means that aperson following an industry code of practice has the same protection as that of an advisory standard under theAct. The statutory defences are covered under section 37 of the Act that states:2.4.1 Defences for div 2 or 337. (1) It is a defence in a proceeding against a person for a contravention of an obligation imposed ona person under division 2 (obligation of employers and others) or 3 (obligation of workers and otherpersons) for the person to prove-..(b) if an advisory standard or industry code of practice has been made stating a way or ways toidentify and manage exposure to a risk-(i) that the person adopted and followed a stated way to prevent the contravention;

88

2.5 Australian standardsAustralian Standards provide useful information which may assist you to meet your obligations. All care shouldbe taken when referring to Australian Standards detailed in the document to ensure it is the current standard.2.6 ReferenceWorkplace Health and Safety Act, Part 4, Divisions 1 and 2.

PART 2. SAFETY MANAGEMENT SYSTEM

5 Managing health and safety5.1 Safety commitment

To be effective, a safety management system requires the commitment and participation of all levels in the millorganisation. Gaining a commitment from workers requires management to demonstrate a corporatecommitment through leadership and example. A demonstrable safety commitment can include:· a commitment by management through example, financial support and priority of business;

89

· accountability for safety as defined in job or position descriptions;· establishment of a safety program and the marketing and monitoring of all aspects of that program;· personal example at all levels; and· compliance with safe work practices and procedures.

5.2 RecommendationsManagement should consider the implementation of a health and safety management system that may include thefollowing elements:· A statement of intent or the formulation of a health and safety policy by management to ensure health andsafety at the workplace.· A safety plan, policy or strategy which may include:· objectives, targets and performance indicators;· use of safe work systems and practices;· promotion of safety; and

90

· training.· A risk management system to minimise the risks to health and safety by:· hazard identification;· risk assessment; and· risk control.· Consultation with employees.· Measurement and evaluation of health and safety performance.· Regular review and improvement.5.3 ReferencesStandards Australia. AS/NZS 4804 Occupational health and safety management systems – General guidelineson principles, systems and supporting techniques.

PART 3. MILL HAZARDS12 Plant

12.1 IntroductionMills have an obligation to eliminate or minimise the risks associated with plant used as part of the milling operations. The risks can be managed by:· Using the risk management approach discussed in section 6 of this code.

91

· Providing training for all new and existing workers who:· operate, maintain, inspect or audit plant;· train others to operate, maintain, inspect or audit plant; and· when new plant is introduced to a mill workplace.· Ensuring the competency of the people operating or maintaining the plant.· Maintaining records.· Consulting with workers about:· hazards and risks associated with plant;· their training needs; and· any proposed changes to plant.· Registering the plant and the design where appropriate.

12.2 Sugar milling plantSugar mills operate fixed plant ranging from boilers and turbo alternators to workshop equipment such as cut off wheels and bench grinders and mobile plant including locomotives, end loaders, forklifts, bobcats and cranes. Registrable plant as listed in schedule 3 of the Regulation (see section 28 of this Code) that are likely to be used at a mill include:· cooling towers;

92

· boilers;· cranes with a safe working load (SWL) greater than 5 t and truck mounted cranes with a moment capacitygreater than 10 m.t;· unfired pressure vessels such as evaporators and vacuum pans; and· vehicle hoists.Plant designs which require registration under schedule 4 of the Regulation include:· cranes with a SWL greater than 5t;· vehicle hoists;· boilers; and· evaporators and vacuum pans.Particular plant with significant risks that do not require registration or where operation is not classified as a prescribed occupation include:· locomotives;· workshop equipment such as grinders, drilling machines and lathes; and· lab equipment such as cutter grinders and disintegrators.In some instances mill management will issue an “Authority to Operate” for various forms of fixed and mobile plant where there is no certificate issued

93

by the regulatory authority. Examples could include an authority to drive a locomotive or to use an explosive powered tool.There is an obligation on the management to ensure that a holder of a certificate has been properly trained and is competent to operate the fixed/mobile plant.

12.3 Risk managementThe ways injury can occur include:· Being struck by machinery, equipment or their by-products. Examples include metal fragments, conveyorbelts, mobile plant and cane bins.· Being caught between moving parts. Examples include being caught between, on or in moving cane bins, mill rolls, sugar dryer and belt and chain drive systems.Methods to reduce or eliminate the risks associated with plant include:· guarding to prevent the operator coming into contact with moving parts;· start/stop switches clearly marked and within easy reach of operators;· use of specific signage;

94

· adequate work space around machines;· specified areas for waste offcuts;· training for operators;· regular maintenance;· good housekeeping standards;· provision and use of appropriate PPE; and· ensuring hair, clothing or jewellery cannot get caught.

12.4 RecordsWhere practicable, management should keep records on:· the item of plant, identification number and design drawings and calculations;· details of maintenance, major repairs and modifications;· audits and inspections;· results of risk assessments;· information, instruction and training given to workers about using the plant and the associated risks;· safe work procedures to be followed where the plant is used.

95

12.5 Recommendations· all persons at the workplace (including persons in supervisory positions and contractors) are to follow thesafe work procedures for plant as identified in specific equipment operating instructions and establishedon-site practices;· create and maintain a system of records to an appropriate standard in relation to plant, training and persons authorized to use such plant.

12.6 ReferencesWorkplace Health and Safety (Plant) Advisory Standard.Workplace Health and Safety Regulation, Parts 2 and 3, and Schedules 3 and 4.Workplace Health and Safety. Risk management workbook – Manufacturing industry.

96

97

References

Gary, J.H. and Handwerk, G.E. (1984). Petroleum Refining Technology and Economics (2nd Edition ed.). Marcel Dekker, Inc.ISBN [[Special:BookSources/0-8247-html Refinery flowchart] from Universal Oil Products' website|0-8247-html Refinery flowchart] from Universal Oil Products' website]].

An example flowchart of fractions from crude oil at a refinery

Watson, Andrew. Agricultural innovation in the early Islamic world. Cambridge University Press. p.26–7.

 Sharpe, Peter (1998).   Sugar Cane: Past and Present . Illinois: Southern Illinois University.

"Crop production" . Food and Agriculture Organization of the United Nations. Retrieved 2010-06-17

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http://www.life.illinois.edu/govindjee/paper/ gov.html#58