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In steel industry , whenever safety is discussed , generally we talk about crane, hoist and sling

certificate & load testing certificate , working at height , SOP & SMP etc..But we generally

forget to talk about safety in Chemical plant like safety in by product plant of Coke Ovens.

It’s need to be circulated widely because if safety practices are not taken care of , any time

havoc can be happened due the high volatile , explosive and highly inflammable nature of few

chemicals produced & handled in by product plant. Out of all sections of Coke Oven

Department , Benzol recovery and Benzol refining & rectification section , where benzene ,

toluene, LS Naphtha are being produced is considered the most hazardous and explosive

nature of plant because of highly inflammable characteristics of benzene , toluene, LS

Naphtha . Out of all aromatic compound , Benzene is considered as most explosive &

hazardous in nature. So to get smooth operation of Benzol Refining & Rectification Plant ,

one should know about various intrinsic characteristics of Benzene, and also safetyprocedures during it’s handling , storage and loading in the Plant., it’s chemical characteristics

like MSDS ( Material safety data sheet ) etc. Otherwise , due to explosive nature it can create

havoc to the plant. Some of physical and chemical data of Benzene are as follows :-

Boiling Point : 80.0 deg.C

Melting Point : 5.51 deg.C

Vapour density : 277

Specific gravity : 0.879 at 20.0 deg.C

Physical state : Liquid

Vapour pressure at 35 deg.C : 100 mm Hg at 261.0 deg.C

Solubility of water at 30.0 deg.C : Insoluble

pH : Normal

Appearance : Colorless

Odour : Aromatic odour

Others : Miscible with alcohol, chloform,Ether, CC4 , Acetone.

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MSDS: [ MATERIAL SAFETY DATA SHEET ] OF BENZENE :-

Formula : C6H6

C.A.S. NO : 71.43.2

U.N.No : 1114

Trade Name : N.G,Benzene

Fire & Explosion Data :-

Flamability : Yes

LEL ( Lower explosive limit ) : 1.4 %

UEL ( Upper explosive limit ) : 8.0 %

Flash Point ( The temp. at which first flash occurred ) : 11.0 deg.C

Auto Ignition Temperature : 362.2 deg.C

Explosion sensitivity to impact : stableHazardous polymerization : Will not occur

Combustible Liquid : Yes

Flammable liquid : Yes

Pyro phoric Material : No

Explosive Material : Yes

Reactivity data :-

Chemical stability : Stable

Incompatibility with other chemicals : Strong oxidizer , chlorine , Bromine and iron.

Reactivity : React vigorously with oxidizing agents . vigor or

incandescent reaction with hydrogen

Hazardous : Forms sensitive explosive mixtures with iodine

pentafloride.

Route of entry : Inhalation , Ingestion skin and eyes.

Effect of exposure / symptoms : Inhalation causes headache , dizziness , dullness ,

repeated contacts lead to pain & readiness.

Ingestion : Burning sensation in mouth and stomach .

Emergency treatment : skin if affected, remove clothes and boots and wash

Thoroughly the affected areas with plenty of water

and soap.

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Eyes : Flush with plenty of water until irritation subsides .

Inhalation : Remove from exposure immediately . If breathing is

irregular or stopped , administer oxygen and seek medical

Aid.

Regulated identification : shipping Name : Benzene,

HAZCHEM CODE : 3WE, Codes / label Flammable

liquid Hazardous waste ID No -5

Due to it’s hazardous nature, special care is to taken during loading and transportation through

tankers. These tankers are of special type and chemical name, code & identification numbers

are written on the body of the tanker. This is called “EMERGENCY INFORMATION

PANNEL”as depicted in Fig- 3.

Permissible levels of Benzene .Toluene & SO2 are as follows :-Substance Permissible limits of exposure

Weighted concentration

( 8 hours)

Weighted concentration

( 15 minutes )

ppm M3/hr ppm M3/hr

Benzene 10 30 ----- -----

Toluene 100 375 150 560

SO2 2 5 5 10

Preventive measures : Avoid contact with liquid and vapors

Personal Protective Equipment : Use hydrocarbon vapors arrestor, Hydrocarbon insoluble

rubber [ PPE ] or plastic gloves , goggles and face shields.

Hydrocarbon insoluble aprons such as Neoprene and shoes.

 

Emergency Fire / First Aid measures :-

Fire :Fire extinguishing media – Foam , carbon Dioxide, Dry

Chemical powder.

Exposure :Inhalation , remove the victim to fresh air , start resuscitation

Spills :Shut off leaks without risk, contain leaking liquid in sand or

earth. Prevent liquid entering into sewerage.

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Waste disposal method : Seal off the waste in vapor tight plastic bags for eventual

disposal.

Additional Information / References :Suspected human carcinogen. Depending on the

duration of exposure , periodic medical check up is recommended . Prolonged exposure(even

at low concn. ) may cause leukemia. Use of alcoholic drink enhances the poisonous effect .

Person with blood disorder should avoid contact with Benzene . High concn. Can lead to

unconsciousness and death. In industry, inhalation is the primary route of chronic Benzene

poisoning. Chiefly through lungs. There is a great individual variation in the signs &

symptoms of chronic Benzene poisoning.

Safety precautions during Benzene handling, storing & loading:- 

Benzene is explosive in nature and it can affect skin . So during production special attention

is needed for Handling:-•  While moving through pipeline static electricity generates at the flange points, so

aluminum jumpers are provided to distribute static electricity to avoid explosion.

•  Is should not be handled with naked hands.

•  Overflow from storage tanks is to be voided during filling the material into the tanks.

•  All storage tanks are to be provided with double earthlings to avoid explosion & fire.

•  All storage tanks are kept within dyke wall to restrict it’s movement during overflow.

•  All pump motors and are to be provided with double earthlings.

•  All pumps with gland leakage collecting trays are needed to provided, to avoid

spilling of benzene on the floor. Drain line should be 65 mm above ground level.

•  Storage tanks need to be provided with spark arrestors to avoid fire during thunders.

Spark arrestor is made of special material which prevents electricity during

lightening.

•  All storage tanks must be equipped with vents to release pressure over the liquid.

•  All tanks must be equipped with summer cooling line to cool tanks body to avoid loss

of benzene ( as it is much volatile material ) in hot summer.

•  All tanks are equipped with water spray as well as foam spray lines to extinguish fire.

•  Drain lines are made to take out material (which cannot be with pump) for cleaning

and repairing tanks. It is below the pump suction line.

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•  As various products are produced in Benzol rectification plant, identification for att

tanks & equipments is necessary.

•  All storage tanks must be painted every year to avoid from damage.

•  All storage tanks must be equipped with ladder to go upstairs for inspection.

•  All storage tanks must be equipped with level indicator to monitor the quantity.

Safety precautions during Benzene loading into the tankers :-

•  All tankers must have permission from Chief controller of explosives

•  All tankers tank must be properly cleaned before loading to avoid contamination

•  Tankers must be provided with “EMERGENCY PANNEL” on the body.

•  All chambers must be with dip pipe for entering material into the tanker.

•  Engine must be switch off during loading.

•  No chamber should be filled up to the neck.

•  Flow of material should be at low speed to avoid fire for kinetic energy.

•  Tankers must be provided with earthing connector during loading.

•  No loading is allowed during thundering to avoid fire.

•  Loading area must be free from dry grasses to avoid fire.

•  Running of other vehicle is not allowed during loading.

•  Loading area must be with fire fighting point in case of emergency.

•  Loading must be completed during day hours only.

•  Before leaving all tankers caps must be properly closed.

If above mentioned precautions are taken, fire & explosion can be avoided in Benzene

producing plant.

Uses of Benzene :-

•  Manufacturing of Insecticides

•  Manufacturing of Nitrobenzene, chlorobenzene

•

  Manufacturing of dyes, drugs , plastics•  Manufacturing of sulphonic acid, styrene

•  Manufacturing of motor fuel ( when mixed with petrol )

•  Use as a solvent also as a base material for making medicines

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