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Asia Pacific Industrial Engineering and Management System

Analysis of the Fire Explosion and Explosion Propagation

Control of Sugar Dust in the Yemen Company for Sugar

Refinery, Hodeida, Yemen

Frras Mohammed Ahmed Othmana, Maida A. Dela Cueva

b

aHayel Saeed Anam Group of Companies, Taiz , YemenbAdamson University,900 San Marcelino St., Ermita, 1000 Manila, Philippines

Abstract

Explosions on sugar refineries of different causes occurred in the past, where there were injured employees,damaged properties, and losses incurred by companies. Engineering and administrative solutions, can reduce the

likelihood of the explosion. This study aimed to create a cost efficient system that will reduce the chance of

explosion in the sugar refinery located in Hodeidah, Yemen, to protect employees, maintain safety and wellness,

and prevent property damages and company losses. The refinery process, with different components from different

work zones, was examined, identifying the areas containing huge amount of sugar dusts, and identifying potential

risks, using Failure mode and Effects Analysis (FMEA). Preventive measures were identified using the hierarchy

of the hazard controls, in conformance to international safety standards. The benefit-cost ratio was determined to

measure the cost effectiveness of the control measures. It has been found out that there is a possibility of sugar dust

explosion. Failure modes are identified with high Priority Risk Numbers (PRN) for different zones. Engineering

solutions such as suppression systems for belt conveyors in transporting sugar, for de-dusting systems, inerting

system for rotary dryer, explosion isolation valves and lightning protection systems were recommended, and have

been calculated to have a benefit-cost ratio of greater than 1.0. Finally, the recommended safety measures include

administrative solutions such as comprehensive housekeeping program, fire prevention and safety program, and

impose permitting systems specially in hot work areas.

Keywords: sugar dusts; explosion; FMEA

1. Background

Sugar dusts are flammable, and sugar refinery plants are susceptible to explosion which may

have devastating and susceptible effects. According to NFPA 654 (Standard for the Prevention of Fire

and Dust Explosions from the Manufacturing, Processing and Handling of Combustible Particulate

Solids) it takes only 0.8 mm layer of dust on the floor covering just 5% of the surface area of a room to

pose a significant explosion hazard. A dust explosion requires the simultaneous presence of two

additional factors - dust suspension and confinement. If any of the five elements are removed, dust

explosions will not occur, although a fire can still occur with oxygen, an ignition source, and the

combustible dust serving as a fuel. Very few employees of the sugar refinery plants are aware of this

risk. Among the 30 employees of the sugar refinery plant in Hodeida, Yemen, 65% are not aware of

the possibility of sugar dust explosions. It is then important to design the facilities to protect the

stakeholders, including the employees, and prevent potential hazards the sugar dust can bring, and

effective control measures should be made.

Hayel Saeed Anam (HSA) Group of Companies is a commercial entity that was established in

Yemen in 1938. Its activities include various investment fields in Saudi Arabia , Egypt, Malaysia and

Indonesia. A new plant of sugar refinery is being built in Hodeida, Yemen the Yemen for Sugar

Refinery (YCSR). The YCSR has a production capacity of the company is 660 thousand tons per year.

At present, the YCSR has a contract with De Smet Engineering and Contractors to provide the

equipment for sugar refinery. Based on the contract, De Smet Contractors will provide de-dusting

system in order to reduce the risks of dust explosions. The de-dusting unit collects sugar dusts from

discharged conveyors below the refined sugar silos and other transporting conveyors and sugar dryer.

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This study aimed at designing preventive and protective procedures to control and reduce

risks of dusts explosions.

2.0 Methodology

The analysis was made based on the three zones of the refinery plant. Each of these zones

was examined. Potential hazards for each zone were identified using Failure Mode Effect Analysis

(FMEA).Failure Mode Effect Analysis (FMEA) concentrates on identifying possible failure modes and

their effects on the equipment and the whole system. Identification of potential failure modes leads to a

recommendation for an effective reliability of the system . Priorities on the failure modes were set

according to the FMEAs risk priority number (RPN) and concentrated effort were placed on the

higher RPN items obtained from the analysis. RPN has been calculated as the product of Severity,

Probability of Occurrence, and Probability of Detection!!"# ! !!!!!!. The values of RPN areshown in Table 1. The company set an RPN of 51 as the critical. The values in red are considered

critical . the subsystem on each zone found to have RPN greater than or equal to 51were studied

further to minimize severity of failure, reduce the occurrence of the failure mode, and improve

detection.

Table 1. Risk Priority Number (RPN) values

Measures to control the potential hazards were identified; The potential benefits of the

proposed control measures, and the costs associated in the installation and maintenance for the

engineering controls were estimated, then the ratio of benefits and costs using the conventional and

modified B/C ratios were determined.

3.0 Result and Discussion

3.1. Facility Description and Sugar Refinery Process

The sugar refinery process starts when the raw sugar will be unloaded by truck coming from the

seaport. There are two unloading stations near to the raw sugar store . The sugar is conveyed by belt

conveyors to the horizontal sugar silo. The sugar pile is done through a mobile head conveyor called

tripper. The tripper is moving along the raw sugar storage. The sugar will be taken by a front loader

to load one of the eight bins to feed the refinery through belt conveyors. The raw sugar is transported to

the process building for refining ,the refined sugar is transported through belt conveyor to the storage

area i.e. Four concrete silos of 3,000 T capacity, are then transferred to the bulk sugar truck or to the

packing buildings. Dozens of screw conveyors and horizontal conveyor belts transport granulated sugar

throughout the packing buildings which house manual or semi-automatic machines to pack the refined

sugar into various sizes. The closed granulated sugar screw conveyors and belt conveyors located

throughout the process , storage silos and dryer are equipped with dust removal equipment including

the equipment installed in the packing building - 1 bag filters to recover the air from dryer , and 1 bagfilters to recover the air from cooler and silos. None of the conveyors, however, is designed to safely

vent overpressure outside the enclosure if combustible sugar dust inside the enclosure is ignited.

10100090080070060050040030020010010

9810729648567486405324243162819

8640576512448384320256192128648

749044139234329424519614798497

636032428825221618014410872366

52502252001751501251007550255

41601441281129680644832164

390817263544536271893

24036322824201612842

1109876543211

10987654321

Severity

ProbabilityofDetection

Probability of accuarnce

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The proposed site lay-out ( Figure 1) gives enough room to transport the refined sugar from the

process building to storage silos by means of belt conveyor instead of bucket elevator. This existing

system (without any bucket elevators) reduces the dust generating and simplifies the risk management

of explosion and fire .

Heat exchangers are installed in various places in the process building by using steam that comes

from the co-generating power plant. Steam comes from the boiler house at 63 bar. In the process house,

two pressure reducing stations are foreseen: One from 63 to 7 bar, other from 7 bar to 2 bar. i.e. The

steam produced is used as heat source in several heat exchangers the temperature of the steam is 107oC.

The steam consumption is approximately 93.2 % of the row sugar refined .

3.2. De-dusting System

There is a separate de-dusting system for the packing building and for the feeder belt conveyor

coming from the sugar storage silos. The aspiration pipes are connected to the feeding belt conveyor

and distributed throughout the plant ,the pipes aspiration points are located near to the opening to the

bagging machine right after the Weighing and dosing equipment .The de-dusting system is located

inside the sugar bagging building. Figure 16 shows the top view of the packing building showing the

general arrangement of the de-dusting system.

3.3. Possible Ignition Sources

Dust explosions occur when an effective ignition source of sufficient energy to initiate flame

propagation is present. Avoidance or elimination of potential sources of ignition is a very important

step in preventing dust explosions. The possible ignition sources that could lead to sugar dust explosion

in the Yemen Company for Sugar Refinery are: Flames and direct heat; Hot work; Hot surfaces;

Electrostatic sparks; Electrical sparks; Friction; Electrostatic; and Lightning, with a 30,0000C and

extreme high current.

3. 4. Possible Sugar Dust Sources

The sugar crystals have sharp edges as seen with the use of microscope. The abrasive nature of

sugar crystals makes the generation of fine particles easy when the particles are brushed against eachother . The rotary movement of the refined sugar inside the rotary drier and transporting it to the

Storage silos where it drops down at elevation of 30 meters makes the formation of sugar dust very

much significant . The sugar dust can be seen at the inlet and out let of transporting conveyors ,

throughout the intervals of the belt conveyor, and inside the storage soils . The sugar dust is sucked

with the use of suction fans which delivers the air with the dust particles to bag filter where 99 % of the

sugar dust gets trapped and collected leaving the air clean from the sugar dust.

3.5. Failure Mode and Effect Analysis

There are 13 subsystems identified in Zone 1, at which potential failure mode can occur, as

shown in Table 2. The potential effects were identified, and the corresponding RPN. Table 3 shows

all possible scenarios that might lead to failure for each potential failure mode for each subsystem, the

causes of failure mentioned in the FMEA spreadsheet are general and the possible scenarios ofpotential causes of failure. There are several failure modes with High Risk Priority Numbers and

should be addressed at the earliest possible time: Carbon dioxide leakage having Risk Priority

Number ( 365 ); Contact with caustic soda having Risk Priority Number ( 350 ); Heat stock to operator

having Risk Priority Number ( 245); Running the pump without water ring having Risk Priority

Number ( 120); and Draw Bodies due to the centrifuge having Risk Priority Number ( 120). The safety

measures taken by the YCSR at this Zone like include: the conveyors are fitted with a speed switch,

security ropes and belt deport detectors. If one switch detects a failure or is activated, the conveyor

gives a warning signal to the control room; and an available static permanent magnet separator. It

removes all the ferrous elements that may lay in the raw sugar such as bolts, nuts.

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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

S.N

Subsystem/

Module &Function

Potential

FailureMode

Potential End

Effects(s) ofFailure

SeverityRanking

Potential

Cause(s) ofFailure

Probability ofOccurrence

Ranking

Current

Controls/Fault

Detection

Probabilityof Detection

Ranking

Risk Priority

Number.Existing(PRN)

Recommended

Action(s)SeverityRanking

Probability

ofOccurrence

Ranking

Probability ofDetectionRanking

NewRPN

1Melter to melt

the raw sugar

Over flow

of mixture

Burning andscalds to

operator.

Down time toplant.

7Failure of

level sensor2

Isolation ofthe tank byheat rated

material

Installation oflevel sensor

4 56

1. Isolation ofthe melterwith guardrail .

2. Wearing the

PPE at alltime .

3. Regularpreventive

maintenance.

3 1 2 6

2Melter to meltthe raw sugar

Burning

incidentdue tocontact

Burning and

scalds tooperator.

6

Damage of

the isolationmaterial

with time

2

Isolation of the

tank by heatrated material

7 84

1. Isolation ofthe melter

with guardrail .

2. Wearing thePPE at all

time.3. Posting

warning

signs.4. Training

programs toworkers .

1 1 5 5

3

Inside theprocessbuilding

Heat stockto operator

Heat relatedillness due to the

hot workingenvironment

7

The natureworking

environmentin the

processbuilding

which

involvesheat.

5Open type

process building7 245

1. Appropriateventilationsystem.

2. Warningsigns.

4 2 4 32

4

Heat exchangerto heat the

Sugar syrup.

Burst ofpipe due to

Pipeblockage

Burning tooperators .

Down time toplant

6No regular

cleaning2 None 8 96

1. Isolation ofthe heat

exchanger2. Precaution

signs.3. Wearing of

PPE at alltime.

3 1 8 24

.

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S.N

Subsystem/Module &

Function

PotentialFailure

Mode

Potential EndEffects(s) of

Failure

Severity

Ranking

PotentialCause(s) of

Failure

Probability ofOccurrence

Ranking

CurrentControls/

Fault

Detection

Probabilityof Detection

Ranking

Risk PriorityNumber.

Existing(PRN)

Recommended

Action(s)

Severity

Ranking

Probabilityof

OccurrenceRanking

Probability ofDetection

Ranking

New

RPN

5

Carbonationvessel for sugar

purification

Carbondioxideleakage

Asphyxia andhealth illness.

7Seal wearand tear

6 None 8 336

1. Providingventilation

system.2. Regular

maintenancefor seals.

3. Wearingbreathingmask at alltime.

4 2 3 24

6

Lime dosingstation for

sugar

purification.

Continuous contact

with Lime

stone

Danger to thelungs and eye in

a long run

exposure

7

Failure ofde-dustingsystem for

lime stone.

3De-dusting

system4 84

1. Regular

maintenancefor filters.

2. Training of

workers .3. Wearing PPE

at all time.

4 2 2 16

7 Vacuum pump

Runningthe pump

withoutwater ring

Pump burns

causingdowntime.

4

Running the

vacuumpump dry.

3 None 10 120

1. Continues

water supplyto the vacuumpump.

2. Preparingcheck listbeforeoperating hepump

2 1 4 8

8

Dosing ofcaustic soda for

declaration

Contactwith

causticsoda

Causes burns

and scarring, cancause serious

damage to allbody tissues

contacted

7The operatordealing with

chemicals

5 None 10 350

1. Training

program for

awareness.2. Precaution

signs .3. Wearing PPE

at all time.

4 2 3 24

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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

S.N

Subsystem/

Module &

Function

Potential

Failure

Mode

Potential End

Effects(s) of

Failure

Severity

Ranking

Potential

Cause(s) of

Failure

Probability

of

Occurrence

Ranking

Current

Controls/

Fault

Detection

Probability of

Detection

Ranking

Risk Priority

Number.

Existing

(PRN)

Recommended

Action(s)

Severity

Ranking

Probability

of

Occurrence

Ranking

Probability of

Detection

Ranking

New

RPN

9

Dosing of

Hydrogen

chloride for

decalaration

Contact

with

Hydrogen

chloride

May causedamage to the

following

organs: Lungs,

Upper

Respiratory

,skin and eye.

7

The operator

dealing with

chemicals

5 None 10 350

1.Training

program for

awareness.

2.Precaution

signs .

3.Wearing PPE

at all time.

4 2 3 24

10

Evaporator

to

concentrate

the sugar

syrup.

Burning o

skin due to

contact

Burning and

scalds to

operator.6

Wear and tear

of isolation5 Isolation 3 90

1.Isolation by

guard rail.2.Regular

preventive

maintenance.

3.Warning

signs.

4.Wearing PPE

at al time.

4 2 2 16

11

Heat

exchanger

to heat the

Sugar

syrup.

Burning o

skin due to

contact

Burning and

scalds to

operator.6

Wear and tear

of isolation5 Isolation 3 90

1.

Isolation by

guard rail.

2.

Regular

preventive

maintenance.

3.Warning

signs.

4.Wearing PPE

at all time.

4 2 2 16

12

Continues

and

discontinues

centrifugal

Draw

bodies

Cut and other

injuries and

may lead to

death due to

the high

kinetic energy

involved in

centrifuge

8Worker contact

with rotatingparts

3 None 5 120

1.Isolation by

guard rail.

2.`Warning

signs.

3.Training of

workers to

increase

awareness..

4 2 5 40

13

Continues

and

discontinues

centrifugal

Mechanical

failure.

Total

destruction to

the machineand injury to

worker due tothe broken

parts

8

Over load

No

preventive

maintenance

1 None 10 80

1.Regular

preventive

maintenance.

2.Wearing PPEat all time.

3.FollowingOperation

manuals

correctly.

4 1 5 20

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Table 3. Scenarios that might lead to failure for each subsystem

S.

No

Subsystem/

Module &

Function

Potential

Failure

Mode

Potential End

Effects of

Failure

Possible scenarios of potential causes of failure.

1Melter to melt the raw

sugarOver flow of mixture

Burning and scalds tooperator.

Down time to plant.

The sensor got damage due to the heat of melter and did not operate causing the over flow of the.

The sensor did not give the signal to the control unit due to loos connection in the wiring .

The floating system of the sensor is filled with sugar syrup disabling the function of sensor.

Excessive voltage.

2Melter to melt the roe

sugar

Burning incident due

to contact.

Burning and scalds to operator.

The isolation is decaying with time.

The isolation wrapping is done poorly by contractor.

The warning sign is not in place .

The operator is not wearing the personal protective equipment

3Inside the process

building

Heat stock to

operator

Heat related illness due to the

hot working environment

The operator is dehydrated due to the low consumption of water .

The ventilation fans are not installed in the process building .

The precaution sign is not installed in the area .

4Heat exchanger to heat

the Sugar syrup.

Burst of pipe due to

Pipe blockage

Burning to operators .

Down time to plant

No regular cleaning before process start up.

The cleaning procedure is no t done adequate.

The Affiation process is not efficient in taking out the impurities before going to the heat exchanger .

5Carbonation vessel for

sugar purification

Carbon dioxide

leakageAsphyxia and health illness.

Over pressure inside the carbonation vessel.

The seals are worn out .

The flanges are not tight enough to prevent the leakage.

6Lime dosing station for

sugar purification.

Continuous contact

with Lime stone

Danger to the lungs and eye in

a long run exposure The bag filters of the de-dusting system is not cleaned regularly.

The operator is not wearing the breathing mask during operation .

7 Vacuum pumpRunning the pump

without water ring

Pump burns causing

downtime.

The operator is not familiar with the running procedure .

The operator did not attend the training course .

8Dosing of caustic soda

for declarationContact with caustic

soda

Causes burns and scarring, can

cause serious damage to all

body tissues contacted

The operator is not familiar with the risk of the chemical .

The operator is not wearing the personal protective equipment.

Lack of patience during loading and unloading of chemical .

9

Dosing of Hydrogen

chloride for

declaration

Contact with

Hydrogen chloride

May cause damage to the

following organs: Lungs,

Upper Respiratory ,skin and

eye.

The operator is not familiar with the risk of the chemical .

The operator is not wearing the personal protective equipment.

Lack of patience during loading and unloading of chemical .

10

Evaporator to

concentrate the sugar

syrup.

Burning o skin due to

contact

Burning and scalds to operator. The isolation is decaying with time.

The isolation wrapping is done poorly by contractor.

The warning sign is not in place .

The operator is not wearing the personal protective equipment .11Heat exchanger to heat

the Sugar syrup.

Burning o skin due to

contact

Burning and scalds to operator.

12

Continues and

discontinues

centrifugal

Draw bodies

Cut and other injuries and may

lead to death due to the high

kinetic energy involved incentrifuge

The operator is not familiar with the running procedure .

The operator did not attend the training course .

The warning sign is not in place. The machine is not isolated and guard .

13

Continues and

discontinues

centrifugal

Mechanical failure.

Total destruction to the

machine and injury to worker

due to the broken parts

Over load of the centrifugal .

Not conducting the preventive maintenance .

Not performing the inspection procedu re before start up.

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There are 21 subsystems identified with potential failures on Zone 2, as shown in Table 4.Table 5

shows as all possible scenarios that might lead to failure for each potential failure mode for each

subsystem, the causes of failure mentioned in the FMEA spreadsheet are general and the possible scenarios

of potential causes of failure. The subsystems that need to be prioritized include Dust Explosion due to hot

work having PRN (450); Dust Explosion due to Stopping the Drum when it is hot and full of sugar

having PRN (350); Dust Explosion due to Hot surfaces like Hot bearings having PRN (300); and DustExplosion due to electro static having PRN (300).The safety measures taken by the YCSR at this Zone

include: the conveyors are provided with a speed switch, security ropes and with belt deport detectors ,If

one switch detects a failure or is activated the conveyor should give a warning signal to the control room;

the conveyor cannot be started without the de-dusting system starting and have to stop in case of failure in

the de-dusting system; In case of shut down of the suction fan of the hot de-dusting system , the alert signal

is appearing in the control room to shut down the dryer; If the drier temperatures are out of range, the alert

signal is appearing in the control room to shut down the feed screw conveyor ; Certified explosion bursting

disc with burst sensor mounted on the outside of the filter unit and the rotary dryer.

There are 8 subsystems identified with Failure Modes as shown in Table 6, four of which

have High Risk Priority Numbers and should be addressed immediately : Dust Explosion due to Hot

bearing having PRN (300); Dust Explosion due to the accumulation of sugar dust having PRN

(300) ; Dust Explosion due to electro static having PRN (240); and Injury of the hand of the operator(piercing) in the sewing machine having PRN (560). The safety measures taken by YCSR in this

zone include: The conveyors are fitted with a speed switch, security ropes and with belt deport

detectors ,If one switch detects a failure or is activated the conveyor is giving warning signal to the

control room; The conveyor cannot be started without de-dusting system starts and have to stop in

case of failure in the de-dusting system; Certified explosion bursting disc with burst sensor mounted

on the outside of the filter unit .

The evaluation of benefits and costs of the recommended actions mentioned in FMEA spread

sheet are shown in Table 8, wherein all the recommended actions have a B/C ratio of greater than 1.0.

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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

S.N

Subsystem/

Module &

Function

Potential

Failure

Mode

Potential

End

Effects(s)

of

Failure

Severity

Ranking

Potential

Cause(s) of

Failure

Probabilit

y of

Occurren

ce

Ranking

Current

Controls/

Fault

Detection

Probabilit

y of

DetectionRanking

Risk

Priority

Number.

Existing

(PRN)

Recommende

d

Action(s)

Severity

Ranking

Probability

of

OccurrenceRanking

Probabilit

y of

DetectionRanking

New RPN

1

Sugar rotary

drier

Dust Explosion

Injury and

chances of

death to

workers

,including

Plant

down time

10

The

Electrical

connection

are no more

Explosion

proof due to

wear and tear

3

Explosion

venting.

Explosion

proof

connection

s.

6180

Regular

preventive

maintenanc

e and

inspection.

6 2 3 36

2 Dust Explosion

May lead

to burning

of sugar

creating

source of

heat and

damage to

the dryer

10

Stopping the

Drum when

it is hot and

full of sugar

5

Explosion

venting.

Explosion

proofconnection

s

7 350

1. Tainting

to

operators

.

2. Followin

gOperatio

nmanuals

correctly

.

7 2 2 28

3 Dust Explosion

Hot

bearings

and

creating

heat

source

10

Excessive

heat and

vibration on

bearings

4

Explosionventing.

Explosion

proof

connection

s

6 240

1. Tainting

tooperators

.

2. Followin

g

Operatio

n

manuals

correctly

.

3. Regular

preventi

ve

maintena

nce and

inspectio

n.

7 1 2 14

4 Dust Explosion

Increasing

the

temperatur

e of dryer

,Creating

source of

ignition

which lead

to dust

explosion

10

Temperature

transmitter

not operating

3

LCD

monitoring

system

5 150

1. Tainting

tooperators

.

2.

Followin

g

Operatio

n

manuals

correctly

.

3. Regular

preventi

ve

maintena

nce and

7 1 2 14

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5 Burning incident

Burning

and scalds

to

operator.

10

No warning

signs are

mounted nearto the dryer

6 Non 8 480

1. Isolation

by guard

rail.

2. Warning

signs.

3. Training

of

workers

to

increase

awarenes

s..

6 2 3 36

6

Belt

conveyor

transportingthe refined

sugar fromDryer to

storage silos

and from

storage silos

to packing

building

Dust explosion

Injury and

chances of

death toworkers

,including

Plant

down time

10Hot surfaces

like Hot

bearings

3De-dusting

system10 300

1. Regular

preventi

ve

maintena

nce

2. Installation off

frictionless

bearings.

3. Impleme

nting the

explosio

n

venting

7 1 3 21

7 Dust explosion

Injury and

chances of

death to

workers

,including

Intensive

destruction

10

Spark due to

the electro

static

3De-dusting

system10 300

1. Groundin

g of the

system. 7 1 7 49

8 Dust explosion

Injury and

chances of

death to

workers

,including

Plantdown time

10Spark due to

hot work5

De-dusting

system9 450

1. Intensive

Tainting

to staff.

2. Special

hot

working

permission.

10 1 7 70

9 Dust explosion

Injury and

chances ofdeath to

workers

,including

Plant

down time

10

Inadequatesystem for

dust suction

inside the

conveyor.

2De-dusting

system10 200

Regularinspection of

filters in the

de-dusting

system.

10 1 5 50

10 Belt Damage

Belt

conveyor

damage

which lead

to Plant

downtime.

7

Overload and

speed

indicator not

operating

3

Overload and

speed

indicator

5 105

1. Tainting

to

operators

.

2. Followin

g

Operatio

n

7 1 2 14

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manuals

correctly

.

3. Regular

preventi

ve

maintena

nce and

inspectio

n.

11 Belt Damage

Belt

conveyor

damagewhich lead

to Plantdowntime.

7

Alignment

sensor not

operating

3Alignment

sensor5 105

1. Tainting

to

operators

.

2. Followin

g

Operatio

n

manualscorrectly

.3. Regular

preventi

ve

maintena

nce and

inspectio

n

7 1 2 14

12

Dedustingsystem for

dryer

Dust explosion of

the system

Injury and

chances of

death to

workers

,including

Plant

down time

8

Spark due to

the electro

static

3 Non 10 240

1. Spark

detection

system.

2. Flameles

s

explosio

n

venting

on pipe.

3. Isolation

quick

closingvalve.

4. Explosio

nsuppressi

on .

5. Groundi

ng of the

system.

4 1 3 12

13 Dust explosion

Injury and

chances of

death to

workers

,including

Plant

down time

8Spark due to

hot work3 Non 10 240

1. Spark

detection

system .

2. Flameles

s

explosio

n

venting

on pipe.

3. Isolation

quick

closing

4 2 4 32

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4. Explosio

n

suppressi

on .

5. Groundi

ng of the

system.

6. Tainting

to

operators

.

7. Special

hot

working

permissi

on.

14

Dedusting

system for

sugar coolerand

conditionin

g

Dust explosion

Injury and

chances of

death toworkers

,including

Plant

down time

10Spark due to

hot work3 Non 10 300

1. Spark

detectionsystem .

2.

Flameless

explosio

n

venting

on pipe.

3. Isolation

quick

closing

valve.

4. Explosio

n

suppressi

on .

5. Special

hot

workingpermissi

on

4 2 4 32

15 Dedusting

system for

sugar cooler

and

conditionin

g

Dust explosion

Injury and

chances of

death to

workers

,includingPlant

down time

10

Ignition

source due

hot

equipmentlike bearings

3 Non 10 300

1. Regularpreventi

ve

maintenance

2. Installati

on off

frictionle

ss

bearings.

3. Impleme

nting the

explosio

n

venting

7 1 3 21

16 Dust explosion of

the system

Injury and

chances of

death to

workers

,including

8

Spark due to

the electro

static

3 Non 10 240

1. Spark

detection

system .

2. Flameles

s

4 1 3 12

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down time n

venting

on pipe.

3. Isolation

quick

closing

valve.

4. Explosio

n

suppressi

on .

5. Groundi

ng of the

system.

17

Storage

silos 4 X3000T

Dust explosion

Damage to

the roof ofsilos and

thefeeding

belt

conveyors,

death of

workers

10Ignition

source due to

hot work

2De-dusting

system8 160

1. Spark

detection

system .

2. Explosio

nventing

3.

Taintingto

operators

.

4. Special

hot

working

permissi

on

8 1 2 16

18 Dust explosion

Damage to

the roof of

silos and

the

feeding

belt

conveyors,

death of

workers

10

Ignition

source due

hot

equipment

like bearings

2De-dusting

system8 160

1. Regular

preventi

ve

maintena

nce

2. Installati

on off

frictionle

ss

bearings.

3. Implementing the

explosio

nventing

8 1 2 16

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Table 5. Possible scenarios of potential causes of failure on Zone 2.

S.No

Subsystem/Module &Function Potential Failure Mode Potential End Effects of Failure Possible scenarios of potential causes of failure.

1

Sugar rotary drier

Dust ExplosionInjury and chances of death to workers

,including Plant down time

The electrical connections are loos without isolation .

Electrical spark due to loose connection.

Hot surface due to the over load of the circuit breaker .

2 Dust ExplosionMay lead to burning of sugar creating source

of heat and damage to the dryer

Failure in the rotating wheel.

The temperature increase inside the rotary dryer.

The operator is not aware of the consequences of the sudden shutting down of the rotarydryer.

The warning sign is not in place .

Unpredicted failure of the monitoring software. .

3 Dust Explosion Hot bearings and creating heat source

Over load of the rotating rollers on the bearings.

Not providing lubrication for the bearings before start up .

Not conducting the preventive maintenance for the bearings.

4 Dust ExplosionIncreasing the temperature of dryer ,Creating

source of ignition which lead to dust explosion

The sensor got damage due to the heat of rotating dryer and did not operate causing theincrease of heat .

The sensor did not give the signal to the control unit due to loos connection in the wiring .

The setting parameters for the software are corrupted .

5 Burning incidentBurning and scalds to operator.

No guard rails to isolate the area.

The operator is not aware of the hazard related to rotary dryer or no PPE.

No warning signs are mounted near.

6

Belt conveyor transporting therefined sugar from Dryer to

storage silos and from storage

silos to packing building.

Dust explosionInjury and chances of death to workers

,including Plant down time

Over load of the rotating rollers on the bearings.

Not providing lubrication for the bearings before start up .Not conducting the preventive maintenance for the bearings.

7 Dust explosionInjury and chances of death to workers

,including Intensive destruction

Spark generated due to the electro static buildup on the surface of the conveyor due to

contact with sugar.

The equipment are not grounded to the earth.

8 Dust explosionInjury and chances of death to workers

,including Plant down time

Residual smoldering particles left over right after the welding process.

No clear instruction and procedure on hot work permit especially for the dust hazard area .

The clearance distance and safe zone arrangement where not done before conducting the

welding process.

9

Belt conveyor transporting therefined sugar from Dryer to

storage silos and from storagesilos to packing building.

Dust explosionInjury and chances of death to workers

,including Plant down time

The preventive maintenance are not carried out for the de-dusting system .

Regular cleaning for the de-dusting system is not done.

The de-dusting pipe is shocked due to the accumulation of dust particles.

10 Belt DamageBelt conveyor damage which lead to Plant

downtime.

The sensor got damage due to the heat and other physical damage.

The sensor did not give the signal to the control unit due to loos connection in the wiring .

The setting parameters for the software are corrupted .

11 Belt Dama eBelt conveyor damage which lead to Plant The sensor got damage due to the heat and other physical damage.

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20 Poisoning Death to worker , or dyspnea or asthma

Breathing the antiseptic chemicals used to killer germs and insects inside the silos .

Breathing the pesticides chemical used to killer germs and insects inside the silos .

The operator not wearing the proper face mask and breathing filters during the process ofapplying the pesticides and the antiseptic chemicals inside the silos.

21 Operator fall Death to worker or major injury Appointing people having phobia of elevation to do the maintenance above the silos.

Not providing guard rails around the silos.

not installing anti slipping materials on footbaths.

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1 2 3 4 5 6 7 8 9 10 11 12 13 14

S.N

Subsystem/Module &Function

PotentialFailureMode

Potential EndEffects(s) of

Failure

SeverityRanking

PotentialCause(s) of

Failure

Probability ofOccurrence

Ranking

Current

Controls/Fault

Detection

Probabilityof Detection

Ranking

Risk PriorityNumber.

Existing (PRN)

RecommendedAction(s)

SeverityRanking

Probabilityof

Occurrence

Ranking

Probabilityof Detection

Ranking

1

Belt conveyortransportingthe refinedsugar from

silos topackingbuilding

Dust explosion

Injury and chancesof death to workers

,including Plantdown time

10Hot surfaces

like Hot

bearings

3 None 10 300

1. Regular

preventivemaintenance

2. Installation offfrictionless

bearings.Implementingthe explosionventing

7 1 3

2

Belt conveyor

transportingthe refinedsugar from

silos topacking

building

Dust explosion

Injury and chancesof death to workers

,including Plantdown time

10

Inadequatesystem for dustsuction insidethe conveyor.

2 None 10 200Regular inspection of

filters in the de-dusting system.

10 1 5

3

Packingbuilding which

contains all

equipment forsugar packing

Dust explosion

Injury and chancesof death to workers

,including Plantdown time

10

Accumulationof sugar duston various

surfaces and

presence ofignitionsource.

3 None 10 300

1. Regularcleaning of the

facility withspecial vacuum.

2. Regularinspection from

the safety incharge.

3. Declaration ofno smoking

zone.

3 1 2

4

De-dustingsystem whichcollects the

dust fromdifferent of thepacking system

Dust explosion

Injury and chancesof death to workers

,including Plantdown time

8Spark due tothe electro

static

3 None 10 240

1. Spark detectionsystem .

2. Flamelessexplosionventing on pipe.

3. Isolation quick

closing valve.4. Explosion

suppression .

5. Grounding ofthe system.

4 1 3

.

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S.N

Subsystem/Module &

Function

PotentialFailure

Mode

Potential EndEffects(s) of

Failure

Severity

Ranking

PotentialCause(s) of

Failure

Probability ofOccurrence

Ranking

CurrentControls/

Fault

Detection

Probabilityof Detection

Ranking

Risk PriorityNumber.

Existing (PRN)

Recommended

Action(s)

Severity

Ranking

Probabilityof

OccurrenceRanking

Probabilityof Detection

Ranking

5

Chute ofweighing

machine for

sugar .

Formation ofsugar dust which

leads to dust

explosion .

Injury and chancesof death to workers

,including Plant

down time

10

Accumulationof sugar duston various

surfaces and

presence ofignitionsource.

3 Non 10 300

1. Regularcleaning of thefacility with

special vacuum.2. Regular

inspection fromthe safety in

charge.3. Declaration on

nonsmoking

zone..

3 1 2

6Packing

machines.

Machine

trapping workerhands while he isfeeding the bags.

Injury to worker 5

Operator not

focused whileperforming the

work.

10 Non 10 500

1. Personnelprotectiveequipment.

2. Manualactivation ofmachineclamps.

3. Training.

3 4 3

7Packing

machines.Back ach of the

operator.Injury to worker 6

Worker lifting

the sugar bagsthe wrong

way.

7 None 8 336

1. Personnel

protectiveequipment.

2. Training

3 4 4

8

Sewingmachine to

close up thesugar bag.

Injury of thehand of the

operator(piercing)

Injury to worker 7

Operator notfocused while

performing thework.

7 None 10 560

1. Personnelprotectiveequipment.

2. Training.3. Installing

mechanicalguard.

3 4 4

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Table 7. The possible scenarios of potential causes of failure are for Zone 3

S.

No

Subsystem/

Module &

Function

Potential

Failure

Mode

Potential End Effects of Failure Possible scenarios of potential causes of failure.

1Belt conveyor transporting the refined sugar

from silos to packing buildingDust explosion

Injury and chances of death to workers ,including Plantdown time

Over load of the rotating rollers on the bearings.

Not providing lubrication for the bearings before start up .

Not conducting the preventive maintenance for the bearings.

2Belt conveyor transporting the refined sugar

from silos to packing buildingDust explosion

Injury and chances of death to workers ,including Plantdown time

The preventive maintenance are not carried out for the de-dusting system .

Regular cleaning for the de-dusting system is not done.

The de-dusting pipe is shocked due to the accumulation of dust particles.

3Packing building which contains all

equipment for sugar packingDust explosion

Injury and chances of death to workers ,including Plantdown time

Not performing the regular cleaning up with the use of vacuum cleaner can leadto accumulation of sugar dust on various locations which can fuel the secondary

explosion.

4De-dusting system which collects the dust

from different of the packing systemDust explosion

Injury and chances of death to workers ,including Plantdown time

Spark generated due to the electro static build-up on the surface of the de-

dusting pipes due to contact with sugar.

The equipment are not grounded to the earth.

5 Chute of weighing machine for sugar .Formation of sugardust which leads to

dust explosion .

Injury and chances of death to workers ,including Plantdown time

Not performing the regular cleaning up with the use of vacuum cleaner can leadto accumulation of sugar dust on various locations which can fuel the secondaryexplosion.

6 Packing machines.

Machine trapping

worker hands while he

is feeding the bags.

Injury to worker Operator is not focused while performing the work.

Performing repetitive work for long time causes the body to fatigue and which

may lead to slower motion and absenteeism of concentration .

7 Packing machines.Back ach of the

operator.Injury to worker

The operator involves himself in bag lifting where he is not supposed to dobecause the machines drops the bags and no need for the operator to interfere .

The wrong ergonomics arrangement which causes the operator to suffer frominjuries.

8 Sewing machine to close up the sugar bag.Injury of the hand of

the operator (piercing)Injury to worker

Operator is not focused while performing the work.

Performing repetitive work for long time causes the body to fatigue and whichmay lead to slower motion and absenteeism of concentration.

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Table 8. Estimated costs and benefits for the recommended systems

Name of system

Estimatedbenefit(saving on

the equipment)equipment that

may get damage

according to thescenario presented

(per 10 years)

InitialInvestment costthe cost of thesuppression

system as per

the quotationgiven by

reliable supplier

ConventionalBenefit to cost

Ratio with

Present worthfactor

ModifiedBenefit tocost Ratio

with presentworth factor

ConventionalBenefit to cost

Ratio with

Annual worthfactor

ModifiedBenefit to cost

Ratio with

Annual worthfactor

Suppressionsystem for thebelt conveyortransporting the

sugar fromprocess building

to storage silos

360,000$ 30,000$ 4.6 7.9 4.6 7.9

Suppressionsystem for thebelt conveyortransporting thesugar from the

storage silo tothe packingbuilding

380,000$ 36,245$ 4.066 6.825 4.066 6.825

Suppressionsystem for the

De-dusting units1,250,000$ 142,569$ 3.468 5.622 3.468 5.622

Inerting systemfor the rotary

dryer360,000$ 35,161$ 4.021 6.807 4.021 6.807

Explosionisolation valves

1,250,000$ 40,000$ 16.802 22.195 16.802 22.195

Lightningprotection

system725,000$ 47,481$ 9.089 16.939 9.089 16.939

4.0 Conclusions/Recommendations

Based on the data gathered from analyzing the existing system in YCSR, the process of sugar

refining requires a lot of heating. The principle used in heating the syrup and hot air for the purpose of

sugar drying is done using heat exchangers with the means of hot steam coming from the coal

burning power plant. This type of heating makes the plant safer than direct heating using burners. The

risk of catching fire in this case is reduced significantly but the hot surfaces present a threat and could

cause dust explosions. Safety management system is not yet fully implemented. The safety team isengaged in a daily work; monitoring the safety procedure to be followed while performing the

installation work done by contractors. It is very important to establish safety management system in

this company before starting the manufacturing operations, else, there could many accidents during the

time of commissioning of the machines due to the presence of unknown threats and unidentified

hazardous places.

The YCSR has implemented the de-dusting unit where the sugar dust is collected to bag filters

which is one of the important safety measures to control sugar dust explosion. The explosion venting is

provided in this de-dusting unit and in the rotary dryer to reduce the damage in case of any explosion.

These two measures cannot protect the equipment plant in case of an explosion. Thus, YCSR needs

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additional safety control measures to reduce the risk of the sugar dust explosion following the hierarchy

of controls.

For zone 1, the following measures are recommended: machine guarding; Reliable

scheduling and documentation of maintenance activity; Implement safe work practices,

instruction and training; strict implementation of PPE wearing zone.

For zone 2, the following measures are recommended: machine guarding; Controlling the

risk using engineering controls stated in the NFPA standards, below are the engineering controls

stated in the NFPA standards; Use Engineering controls as referred to NFPA standards such as

Spark /Ember detection and suppression system, Deflagration detection and suppression

system, Lightning protection system, Automatic fast acting valve system, System grounding,

and Portable Electric vacuum cleaners; Reliable scheduling and documentation of maintenance

activity; Implement safe work practices, instruction and training; Strict implementation of PPE

wearing zones.

For zone3, the following measures and recommended: Control the risk using

engineering controls stated in the NFPA standards such as Spark /Ember detection and

suppression system, deflagration detection and suppression system, lightning protection

system, automatic fast acting valve system, system grounding, and portable electric

vacuum cleaners; Reliable scheduling and documentation of maintenance activity;

Implement safe work practices, instruction and training; strict implementation of PPE

zones.

All of the solutions mentioned have a B/C ratio of greater than 1.0, which means that the benefit

that the company can gain is greater than the costs to be incurred.

The implementation of the hierarchy control especially the proposed engineering solution can

save life and properties of the company, not only that but it can insure continuous operation of the

plant, reduced risks, increased productivity, healthier and happier better motivated employee, better

reputation among investors, customers and communities. The proposed solution is justified to have

more benefits comparing to the investment cost and besides, implementing this control measure can

lead to less premium paid to the insurance company as well . Safety is a corporate objective like sales

and profit. Safety is profitability in terms of saving lives, saving properties from being damage,

increased quality in products, decreased workers compensation claims savings when workers do not

have to be replaced or retrained due to accidents, and potential reductions in health and insurance

costs.

It is further recommended in the future to have periodical risk assessment; administrative

programs like training ( specially dust hazard awareness) and comprehensive housekeeping be created

to engage employees in controlling the dust accumulation, emergency evacuation plans, fire and

rescue drills must be conducted to be prepared in case of any incident, use belt conveyor designed with

explosion venting; impose permitting systems to hot work and confined spaces; install fire alarm and

fire fighting system; maintain bearing according to the manufacturers recommendations; prohibit the

use of compressed air to clean the dust.

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5.0 References

[1] Abbasi, T. (2006).Dust Explosions- Cases, Causes, Consequences and Control. India:

Pondicherry University.

[2] Australian Government Department of Resources and Energy Tourism. (2008).Risk Assessment

and Management. Australia: Department of Resources and Energy Tourism.

[3] Barton, John. (2002). Dust Explosion Prevention and Protection. USA: Gulf Professional

Publishing.

[4] Bridges, W. (2011). Selection of Hazard Evaluation Techniques. Retrieved: December 5, 2012,

From http://process-improvement-institute.com/index.html

[5] Eckhoff, R. (1997). Dust Explosions in the Process Industries, 2nded. Great Britain: Reed

Educational and Professional Publishing Ltd.

[6] Cote, A. (2003).Fire Protection Handbook, 19 thed. Quincy, MA: National Fire Protection Association.

[7]Dust Explosion Venting Protective Systems BSEN 14491. (2006). UK: British Standard.

[8]Explosion Isolation Systems BSEN 15089. ( 2009). UK: British Standard.

[9]Explosion Suppression Systems BSEN 14373. (2005) UK: British Standard.

[10]Explosion Venting Devices BSEN 14797. (2006) UK: British Standard.

[11] Glendon, A. ( 2006).Human Safety and Risk Management. Florida: Taylor and Francis Group.

[12] Glor, M. (2010).Ignition Hazards Caused by Electrostatic Charges in Industrial Processes.

Switzerland: Swiss Institute of Safety and Security.

[13] Gould, J. ( 2000).Review of Hazard Identification Techniques. Sheffield: Health and Safety

Laboratory.

[14] Health and Safety Executive. (2011).Five Steps to Risk Assessment. UK: HSE Books

[15] Hugot, E. (1986).Handbook of Sugar Cane Engineering. Amsterdam: Elsevier Science

Publishers B.V.

[16] International Finance Corporation. (2007).Environmental, Health and Safety Guidelines for

Sugar Manufacturing. USA: International Finance Corporation.

[17] Lipol, L. (2011). Risk Analysis Method: FMEA/ FMECA in the Organizations.International

Journal of Basic and Applied Sciences/ JBAS/ JENS, 11, 74-82.

[18]NFPA 12 Standard in Carbon Dioxide Extinguishing Systems. (2005) Quincy, MA: National Fire

Protection Association.

[19]NFPA 61 Standard for the Prevention of Fires and Dust Explosions in Agricultural and Food

Processing Facilities. (2008) .Quincy, MA: National Fire Protection Association.

[20]NFPA 68 Standard on Explosion Protection by Deflagration Venting. (2007). Quincy, MA:

National Fire Protection Association.

[21]NFPA 69 Standard in Explosion Prevention Systems. (2008). Quincy, MA: National Fire

Protection Association.

[22]NFPA 70 National Electrical Code. (2002). Quincy, MA: National Fire Protection

Association.

[23]NFPA 654 Standard for the Prevention of Fire and Dust Explosions from the Manufacturing,

Processing, and Handling of Combustible Particulate Studies. (2006). Quincy, MA: National Fire Protection

Association.

8/11/2019 Analysis of the Fire Explosion and Explosion Propagation

24/24

[24]NFPA 2001 Standard on Clean Agent Fire Extinguishing Systems. (2004). Quincy, MA: National

Fire Protection Association.

[25] Pain, S. (2010). Safety Health and Environmental Auditing A Practical Guide . Florida: CRC

Press Taylor and Francis Group.

[26] Park, C. (2004).Fundamentals of Engineering Economics . New Jersey: Pearson Education, Inc.

[27] Peetz, Ben. (2012, March).Combustible Dust Fires and Explosions. Retrieved: January 1, 2013, From

http://www.fireengineering.com/index.html

[28] Pritchard, C. (2001).Risk Management Concepts and Guidance. Virginia: ESI International.

[29] Rochester Institute of Technology. Cost Benefit Analysis. Retrieved: December 31, 2012.

From:https://www.rit.edu/~woutrea/training/Module5/M5_CostBenefitAnalysis.pdf

[30] U.S. Chemical Safety Board.Investigation Report: Dust Explosion and Fire Imperial Sugar Company. (2009). USA:

U.S. Chemical Safety and Hazard Investigation Board.

[31] Van der Poel, P.W. (1998). Sugar Technology Beets and Cane Sugar Manufacture. Berlin: Bartens.