PowerPoint Presentation · Tightness across forehead, headache within 1-2 hours 200 ppm Severe headache, throbbing sensation in the head, dizziness, caused within 1-2 hours 600 ppm

19.02.2019

Copyright © 2010 Jindal Steel & Power Ltd.

Prevention of hazardous conditions leading to gas poisoning, explosion and fire in gas lines and equipment including connected accessories.

Updating operating and maintenance procedures to avoid hazardous in the gas lines and gas hazardous aggregate.

To create awareness among all working people about the basic principles of gas safety to be followed at the time of operation.


In our Steel Plant following Process Gases are used

Oxygen Nitrogen Argon CO gas BF gas Syn Gas These gases are used as fuels to reduce the

overall cost of energy and ultimately save money.


Constituents

Raw Gas from

CGP

Crude CO

Gas

Clean co Gas BF Gas

Carbon

Monoxide (%)

24.62 6-9 6.75 22.0

Hydrogen (%) 38.92 55-60 55 1.8

Methane (%) 9.66 24-28 25.46 0.4

Carbon Dioxide

(%)

25.41 3-4 2.5 21.0

Nitrogen (%) 0.19 3-7 3.9 56.0

Oxygen (%) - 0.3-0.5 0.4 0.5

CnHn (%) - 2-2.6 3.19 -

CnH2n+2 (%) 0.35 - - -

H2S (%) - 0.4 0.18 -

Naphthalene

(g/Nm3)

- 0.65 0.32 -

Analysis

ESSAR STEEL (HAZIRA) LTD


Constituents BF Gas Raw Gas CO Gas

Ignition Temp.

(°C) 600-650 600-650 550-600

Explosive

Range (%) 45-70 5.44 – 48.73 7-30

Sp. Gr. 1.05 0.721 0.42-0.45

Calorific Value

(Kcal/ Nm3) 700 - 800 2659 4300-4500

Nature Poisonous,

Colorless, Odorless,

Explosive, burns with

blue flame, heavier

than air

Poisonous,

Colorless, typical

pungent smell of

H2S, Explosive,

burns with yellow

flame, lighter than air

Explosive, Colourless,

typical smell of hydrogen

sulphide and

naphthaline, burns with

yellow flame, lighter than

air

REVIEW OF GAS PROPERTIES


Explosive Limits

Sl. No. Description Lower and Higher

Explosives limits (%)

1 Blast Furnace Gas 45.0-70.0

2 Corex Gas 10.0 – 72.0

3 Producer Gas 7.8 – 57

4 Syn Gas 5.38 - 49.51

5 Natural Gas 4.8- 13.5

6 Converter Gas 20.0- 70.0

7 Coke Oven Gas 7.0- 30.0

8 Acetylene 2.5- 80.0


Effect of Common Gases on Human Beings

Sl. No. Item Properties/ Hazards Threshold

Limit Value

(TLV)

1 CO Highly toxic, combines with hemoglobin in blood, promotes suffocation. O2

asphyxia is followed by headache, weakness, dizziness vomiting, fainting,

collapse, coma, respiratory failure and death.

50 ppm

2 NH3 Strong irritation to eye, skin and lungs, causes cough and respiratory collapse 25 ppm

3 Cl2 Highly irritating to eye, skin, mucous lining of respiratory track. Causes

stinging, burning and redness of eyes and skin, high blood pressure discomfort

and respiratory collapse.

0.5 ppm

4 SO2 Extremely irritant to eye, skin and throat, causes respiratory paralysis 5 ppm

5 CO2 Giddiness, suffocation, unconsciousness and nonflammable 5 ppm

6 N2 Non-toxic, inactive and non-flammable, Sole presence of N2 causes asphyxia

7 Benzene Colourless liquid with aromatic odour, Narcotic and high damage, headache,

fatigue, dizziness, loss of appetite, leukemia, dermatitis damage of liver

10 ppm


Effect of Common Gases on Human Beings

Sl. No. Item Properties/ Hazards Threshold Limit

Value (TLV)

8 Acetylene High explosive, low toxicity. -

9 H2S Colourless having rotten egg smell, explosive when inhaled,

results in pain and burning sensation in eyes, nose and throat,

headache, sleeplessness, dizziness.

10 ppm

10 Hydro

carbons

There is presently no indication of any direct health effects on

population of gaseous hydrocarbons (HC) in ambient air

although as reactants in photochemical processes. It can

indirectly be linked with adverse health effects of resultant

photochemical oxidants.

Injury to sensitive plants has been reported from ethylene

concentration ranging from 0.001 to 0.3 ppm over a period of 8

to 24 hours.

11 Nitrogen It exists predominantly in two forms NO and NO2. NO is not

considered to have adverse health effect at concentrations

presently found in atmosphere were as NO2 is more toxic than

NO. long term exposure of NO2 to levels between 0.06 and 0.09

ppm is associated with increased bronchitis.


Sources of Gas Poisoning

Raw gas : Contains about 24 % of CO

Syn gas : Contains about 32.00 % CO

Coke Oven Gas : Contains about 6.4% CO

Blast Furnace Gas : Contains about 23 to 28% CO

Producer Gas : Contains about 23% CO

Mixed Gases : Used in Battery

Un-burnt Carbon monoxide in all products of combustion

such as flue gases of furnaces.

Oxy-Acetylene and Arc-Welding in closed spaces.


Sources of Gas Hazards

Asphyxia or Suffocation

Up to reduction of 19% : There is no harmful effect

Between 14% and 15% : Oxygen hunger becomes

apparent with symptoms of

increased heart

rates and depth of respiration.

A level of 8% to 10% : Causes unconsciousness

Below 4% : Breath is arrested


Sources of Gas Hazards

Explosions and Fire

The Blast Furnace, Coke Oven Gas, Producer Gas,

Natural Gas and Mixed Gases form inflammable mixtures with

certain percentage of air. These mixtures can cause explosion

when ignited by some source such as fire, welding spark, etc.

The chances of explosion are very high in the following

conditions:

While taking a gas pipe line in to operation and out of

operation or shutdown.

While lighting up a furnace or shutting down a furnace.

While repairing a gas line.


Effect of Carbon Monoxide on Human Beings

Carbon Monoxide

content in air

Effect

50 ppm None

100 ppm

Tightness across forehead, headache within 1-2 hours

200 ppm

Severe headache, throbbing sensation in the head, dizziness, caused within 1-2 hours

600 ppm

Severe headache, weakness, shortness of breath, dizziness, dimness of vision within 1-2 hours

800 ppm

Unconsciousness, depressed heart action and respiration, possibly death within 2 hours

1000 ppm

Weak pulse and slower respiration, respiratory failure and death within 2 hours


Carbon Monoxide Poisoning and Treatment

The CO gas is colourless, odourless, tasteless and non-irritating. When a

man is affected by gas, throbbing sensation in the head, a feeling of weakness

in the knees, mental confusion, headache, roaring in the ear, nausea or

vomiting (either all or some of these) may appear. The second stage is

characterized by increasing paralysis and confusion. The headache, dizziness

and inability to think clearly and act with energy, increase and render the victim

helpless. Even when there is scope for him to come out, he in unable to come

out and he may succumb(Fatality).

A person working in a possible gaseous atmosphere should therefore never

ignore headache or any other symptom and should get into clean fresh air

immediately.

The work should be resumed only after checking the concentration of carbon

monoxide with the aid of detectors or instruments. The permissible

concentration of carbon monoxide in breathing air is 50 ppm.


Action to be taken in case of persons gas poisoned

One should not get panic. Try to remove the victim to fresh air

quickly, taking care of self.

Loosen the garments of the victim but keep the victim warm.

Inform Plant First-Aid Centre, Gas Facilities Department and

Safety Engineering Department.

Do not allow a crowd to be formed around the victim.

Give artificial respiration, if it is known.

Send the victim to the Plant Medical Unit on arrival of an

Ambulance along with escort.

Administering of oxygen should be done by a trained person till

the patient reaches the Plant Medical Unit.


The following points to be kept in mind always regarding gas poisoning

Every one is susceptible to the poisonous gases.

There is no natural or acquired immunity to the gas.

On mild exposure the symptoms will pass of after coming to

fresh air free of gas, leaving only a slight headache.

Repeated exposure produces identical effects.

Prolonged exposure will end the life.


Prevention of gas poisoning

Blast Furnace, DR tail gas and Mixed Gases contain good amount of carbon

monoxide, a very poisonous and harmful constituent. Carbon monoxide in

breathing atmosphere in excess of 0.02% by volume can cause death on

prolonged exposure. Moderate exposure to this gas can cause dizziness,

headache or suffocation.

To avoid gas poisoning, no gas valve should be left open allowing gas into a

room or building or any enclosed space, such as pit, sewer, sump or tank etc.

Gas mask should always be used on jobs to be performed in atmosphere

contaminated with carbon monoxide.

Never enter a furnace, tank, gas main or closed space where gas is suspected

to be present without prior gas analysis or by a detector and without a gas mask

or any other safety apparatus. When a man enters into such space, with safety

apparatus on, an observer must be stationed outside the gas free atmosphere,

belt and life line be attached to the man inside so that in case of distress of the

latter, he can be hauled out.


Prevention of gas poisoning

All possible ventilation should be used when there is any

risk of gas in the atmosphere particularly in an underground

sump or pit.

While working on live gas main or on a main with leaking

valve which involves the escape of gas into surroundings

atmosphere, advantage of wind direction should be taken.

When operating bleeders, see that the gas is not allowed

to blow over men working in the vicinity.


Sources

Improper purging of the gas lines and equipment.

Improper charging of a gas main.

Adopting wrong procedures in lighting a furnace.

Discharging bleeder from the gas mains into any place where gas is likely

to come into contact with a source of ignition.

Ignoring the dead pockets in the shut-off gas lines.

Gradual and unexpected gas leakage from broken or cracked valves/ gas

lines (specially Coke Oven Gas) into closed and semi-closed spaces,

which may include pockets under the furnace platforms, underground or

over ground galleries or unauthorized sheds around or near the furnaces.

Gas jobs conducted in such places can also cause explosion.

Burns to persons may be caused by the unexpected ignition of gas leaks

or pockets of gas around gas main or equipment or by back flash during

lighting of furnace.


Action to be taken in case of fire in gas mains

If gas catches fire during work or through some cracks or

because of some leakage, it should be extinguished with

foam, clay, steam or water. The portion of the gas main should

be cooled down with water and only after the fire is

extinguished, should the main valve be closed completely.

It should be remembered that the valve is not to be closed

when fire is still there and the pressure in the main is

maintained at a minimum of 100 mmwc.


No one should take rest or sleep near gas systems including valves, gas lines, joints, seal pots and in gas hazardous areas.

It is prohibited to make a fire or to smoke near the gas valves, gas line joints, compensators, condensate drainers and the gas booster and mixing stations, or where gas jobs are going on.

No gas burners shall be kept burning inside the furnace or in close spaces without an attendant.

Gas masks should be used while working in atmosphere contaminated with poisonous gases.

No single person should work in boilers, deep trenches, tunnels etc.

Wearing of shoes with iron nails on gas lines is strictly prohibited.

Control room, booster houses or other rooms where gas pipes and impulse lines are taken for connection to instruments, should always be properly ventilated.

When a furnace or gas equipment including gas lines is taken down for repair 100% isolation is to be ensured either by a plate type of isolator or by the insertion of a blank plate down stream of the valve.

All purge points, bleeder pipes and valves should be pre checked before blanking or de-blanking job on the gas lines. The first purge point should be close to the place of blanking or de-blanking. Gas, steam, nitrogen and air should freely pass through bleeders.


GAS DANGER” or caution boards should be fixed at all the gas dangerous places in all the shops.

Before entry into confined places like boilers, chambers, vessels, pipelines, oxygen content must be checked for safe working, it should not be less than 19%.

The gas equipment, water drains, etc. should be inspected periodically by competent persons. All joints, valves, cocks and water seals should be free from leakages. Gas leakages should be rectified immediately and in the meantime nobody should be allowed to stay in that area.

Checking for leakage of coke oven gas or blast furnace gas or mixed gas should only be done by soap solution or with the help of CO monitor.

A manometer should be installed in the line on which work is going on under controlled gas pressure. It should be nearest to the point of work.

For welding jobs on gas lines, it must be done only after a blank plate is inserted before the place where welding is to be done and the line has been thoroughly purged out. Clearance and permission for such jobs are to be obtained prior to the start of the job.

Emergency gas mask should be kept in control room of each shop having hazardous places. In case it is used, gas rescue and alarm station should be informed for checking and refilling. The safe custody of the emergency gas masks is primarily the responsibility of the shop concerned.


All gasmen and workers dealing with gas equipment should be regularly trained in using gas masks, first-aid methods (including artificial respirations).

When working on gas lines at a height a suitable platform with convenient escape ways should be created. If this is not possible, safety belt and life line must always be used.

Explosion proof electric torch light must always be used for the inspection of inside of gas mains and furnaces, seal pots and all enclosed spaces where traces of gas are likely to be present.

Never use a naked light/ fire in the vicinity of an enclosed space, which may contain inflammable gas or near any gas main or equipment.

No welding and cutting jobs are allowed in the areas where gas is likely, to be present without clearance from the Competent Authority.

For all gas jobs, proper plan of work should be drawn out by the department concerned (owner of the asset), involving Gas Facilities, Safety Engineering and Fire Service Departments as required for the job. A job coordinator should be nominated from the Department concerned for executing the job.

All who are required to work in gas hazardous placed and all those who are connected with the maintenance of gas lines/ equipment and operation of gas fired furnace/ drying ovens must undergo basic and refresher courses in gas safety practices.


All shop In charges shall arrange to draw out emergency and day to day operational instructions in connection with use of gas in their shop, which should be made available in the control room/ production control, all the time, such instructions may be compiled by the shop and checked by the Gas Facilities Department and approved by the Head of the Department.

A systematic scheme of gas lines in the shop indicating all the valves, throttles, bleeders, water drainers, position of purge points should be displayed in the control room. Such a scheme helps in normal work as well as in emergency situations.

The man In-charge of the job is expected to be familiar with the use and safe operation of gas masks and is responsible for the proper fitting of the mask to the wearers on any job.

In case of locked buildings with nobody in attendance under emergencies, the main valve may be closed without checking the inside valves in these buildings but under no circumstances must the gas be put back into this building without checking that all valves are closed.

The sequence of jobs should be followed rigidly.

No operation should be conducted in haste which can jeopardise safety.

No work should be taken up till the line clearance is clearly given and accepted by authorized person. All personnel except working group for cutting operations are to be removed from the entire area.


Night operations should be avoided unless in case of emergency.

Isolated equipment or main should be monitored for leakage till recharging and this should be logged.

The Department will maintain a list of authorized persons. Only copper tools should be used for operations like

scrapping, cleaning of surface, etc. Wherever copper tools cannot be used, e.g. spanner etc., the tools should be smeared with grease to eliminate chances of generating spark.

The area of work should be properly condoned off and entry of unauthorized persons is prohibited.

Whenever a job is undertaken in an enclosed space or NOT IN OPEN AIR, use of explosive meters should be resorted to for monitoring the gas concentration and ensuring that the area, equipment/ line is free from an explosive mixture.

Gas Process scheme of Coke oven

25

Water-tar removal Raw gas

(from

battery)

Tar decanting Ammonia

water (to

battery)

Tar

Primary cooling

Electr. detarring

H2S scrubbing

NH3 scrubbing

BTX / C10H8

scrubbing

gas

liquor

Exhausters

distilled water NH3 stripping/

deacidification

Elementary

sulphur recovery

(Claus plant)

NH3/H2S stream

Sulphur

Biologic

waste water

treatment

Treated

water

Plant utilities

(Cooling water,

Steam,

Nitrogen,

Compressed Air,

Power, etc.)

coal

water

Rich solution

Gas Booster

Batt-1&2

Flare Stack

Clean gas to consumer

PPT -2/Ammonia and Sulfur washing.pptx

PPT -2/CLAUS FURNACE.pptx

PPT -2/Back Up of PPT.pptx


What is purging? ◦ The dictionary meaning of “PURGE” is getting rid of harmful or

undesired elements.

◦ Interposing of inert medium while charging and discharging is known as purging in the context of gas safety.

What are the medium used for purging? ◦ Steam

◦ Nitrogen

◦ Carbon dioxide

◦ Argon

Common purge medium in Steel Plant? ◦ Steam

◦ Nitrogen


DRIP

POT

BRANCH FROM

GAS HEADER

VENT

GAS HEADER

OVER

FLOW

NI HEADER

TCV

BCV

ISOLATION

VALVE

HOSE

SAMPLING

POINT

DRAIN

LINE

BLEEDER

VENT

CONSUMER


Comparison of Steam with Nitrogen

Sl.

No. Parameter Steam Nitrogen

1 Time for purging More less

2 Sample collection Not possible Possible

3 Condensation Yes No

4 Pipeline becoming hot Yes No

5 Impulse line connections To be closed Need not be closed

6

Removal of tar deposits, declogging of

burners Yes No

7

Entry into the pipeline / equipment after

purging Safe

Unsafe, to be checked for

oxygen content and if required

compressed air is to be blown in

8 Bleeders

Should not be closed after

purging Can be closed after purging


Activities: ◦ Preparation of protocol identifying the activities, responsibilities and

coordinator ◦ Preparation of charging scheme ◦ Opening of end bleeders ◦ Purging with Steam or Nitrogen ◦ De blanking of valve ◦ Purging of line with Steam or Nitrogen

If purging is done with Nitrogen: ◦ To take sample of purge Nitrogen ◦ Check for Oxygen content ◦ If Oxygen is less than 1% charge the line with gas by opening the

isolation valve. ◦ Close the bleeder


Charging of Gas Main

◦ If purging is done with Steam: Observe the steam coming out of the bleeders

Open the isolation valve and charge the line with gas

Take sample of the bleeding gas

If Oxygen is less than 1% close the bleeder


Discharging of Gas Main ◦ Preparation of protocol identifying the activities, responsibilities and

coordinator ◦ Preparation of discharge scheme ◦ Closing of isolation valve ◦ Opening of end bleeder ◦ Depressurizing of the line ◦ Purging with Steam or Nitrogen ◦ Check for CO % and explosive mixture ◦ Give clearance for blanking ◦ Blanking of the line after the isolation valve ◦ Purge the line with Steam or Nitrogen ◦ Check for CO % and explosive mixture and give clearance for hot works

like welding and gas cutting


Protective Equipment: ◦ Oxygen breathing apparatus

◦ Travox-120

◦ SR-45

◦ SR-30

◦ Compressed air masks

Monitoring Equipment: ◦ CO Monitor

◦ Explosive meter

◦ Oxygen Monitors


THANKS

Documents

PowerPoint Presentation · Tightness across forehead, headache within 1-2 hours 200 ppm Severe headache, throbbing sensation in the head, dizziness, caused within 1-2 hours 600 ppm