“Manufacture Storage & Import of Hazardous Chemicals...

Environmental Impact Assessment for the Proposed 10.0 MTPA Integrated Steel Plant, 900 MW Captive Power Plant and Township near Barenda Village, Sonahatu Block, Ranchi District, Jharkhand State

Chapter-7 Additional Studies

VIMTA Labs Limited, Hyderabad C7-1

7.2 Risk Assessment1

7.2.1 Introduction

Industrial activities, which produce, treat, store and handle hazardous

substances, have a high hazard potential to safety of man and environment at

work place and outside. Recognizing the need to control and minimize the risks

posed by such activities, the Ministry of Environment & Forests have notified the

“Manufacture Storage & Import of Hazardous Chemicals Rules” in the year 1989

and subsequently modified, inserted and added different clauses in the said rule

to make it more stringent. For effective implementation of the rule, Ministry of

Environment & Forests has provided a set of guidelines. The guidelines, in

addition to other aspects, set out the duties required to be performed by the

occupier along with the procedure. The rule also lists out the industrial activities

and chemicals, which are required to be considered as hazardous.

The proposed project will be producing steel from iron ore and other raw

materials. During the process of manufacture of steel and other associated

materials hazardous gases are generated which are stored and used within the

plant process. In addition to this also some other hazardous chemicals, which are

required in the manufacture of steel or produced as a by-product, being stored

and handled in plant. The major chemicals handled / stored by the plant includes

coke oven gas (COG), blast furnace gas (BF gas), basic oxygen furnace gas (BOF

gas), LPG, different acids etc. In view of this, proposed activities are being

scrutinized in line of the above referred “manufacture, storage and import of

hazardous chemicals rules” and observations / findings are presented in this

chapter.

7.3 Approach to the Study

Risk involves the occurrence or potential occurrence of some accidents consisting of

an event or sequence of events. The risk assessment study covers the following:

Identification of potential hazard areas;

Identification of representative failure cases;

Visualization of the resulting scenarios in terms of fire (thermal radiation) and

explosion;

Assess the overall damage potential of the identified hazardous events and the

impact zones from the accidental scenarios;

Assess the overall suitability of the site from hazard minimization and disaster

mitigation point of view;

Furnish specific recommendations on the minimization of the worst accident

possibilities; and

Preparation of broad disaster management plan (DMP), on-site and off-site

emergency plan, which includes occupational and health safety plan.

7.4 Hazard Identification

The following two methods for hazard identification have been employed in the

study:

1 Risk assessment as per ToR-63




Identification of major hazardous units based on manufacture, storage and

import of hazardous chemicals rules, 1989 of Government of India (GOI rules,

1989); and

Identification of hazardous units and segments of plants and storage units based

on relative ranking technique, viz. fire-explosion and toxicity index (FE&TI).

7.4.1 Classification of Major Hazardous Units

Hazardous substances may be classified into three main classes namely flammable

substances, unstable substances and toxic substances. The ratings for a large

number of chemicals based on flammability, reactivity and toxicity have been given

in NFPA Codes 49 and 345 M. The major hazardous materials to be stored,

transported, handled and utilized within the facility have been summarized in the

Table-7.3. The fuel storage details and properties are given in Table-7.4 and

Table-7.5 respectively.

TABLE-7.3

CATEGORY WISE SCHEDULE OF STORAGE TANKS

Materials Hazardous Properties

Blast furnace gas (carbon monoxide)

UN 1016. Dangerous Goods Class 3 – Flammable Gas

Coke oven gas (hydrogen) UN 2034. Dangerous Goods Class 3 – Flammable Gas

Coke oven gas (methane) UN 1971. Dangerous Goods Class 3 – Flammable Gas

BOF gas (carbon monoxide)

UN 1016. Dangerous Goods Class 3 – Flammable Gas

LPG UN 1972. Dangerous Goods Class 3 – Flammable Gas

LDO UN 1203. Dangerous Goods Class 3 – Flammable Liquid

HFO UN 1202. Dangerous Goods Class 3 – Flammable Liquid

TABLE-7.4

HAZARDOUS MATERIALS STORED, TRANSPORTED AND HANDLED

A Material No. of

Tanks Capacity

(Storage Condition)

1 Blast furnace gas (carbon monoxide)

2 50,000 m3

gaseous, ambient temperature and pressure

2 Coke oven gas (hydrogen & methane)

2 50,000 m3


3 BOF gas

(carbon monoxide)

2 50,000 m3


4 LPG 3 50 T liquid & pressurized

5 HFO 2 1000 m3

6 LDO 2 250 m3




TABLE-7.5

PROPERTIES OF FUELS USED IN THE PLANT

Chemical Codes/Label TLV FBP MP FP UFL LFL

°c %

Blast furnace gas (carbon

monoxide)

Flammable 50 ppm -191.45 -205 - 74 12.5

Coke oven gas (hydrogen)

Flammable - -252.8 -259.2 - 74 4

Coke oven gas (methane)

Flammable 1000 ppm -161.5 - -187.8 15 5

BOF gas (carbon

monoxide)

Flammable 50 ppm -191.45 -205 - 74 12.5

LPG Flammable 1000 ppm -0.5 -187 <-60 8.5 1.8

LDO Flammable - 371 - 54.4 6 0.7

HFO Flammable 14 >350 - >62 5 0.5

TLV : Threshold Limit Value FBP : Final Boiling Point

MP : Melting Point FP : Flash Point

UEL : Upper Explosive Limit LEL : Lower Explosive Limit

7.4.2 Physio-Chemical Properties of Hazardous Chemicals Stored/Used

The physio-chemical properties of BF/CO gas (toxic component is carbon

monoxide), LPG and liquid oxygen are given below:

Blast Furnace Gas (BFG)

BFG is a by-product of the iron making process and is used as a fuel gas. It is an

odourless, colourless and toxic gas. Its toxic properties are due to the presence of

carbon monoxide (CO) (typically 21-25% v/v) in the gas. In confined space, it can

form explosive mixture.

BFG is a very low heating value fuel (CV=800-900 Kcal/nm3), containing inerts of

approximately 58% nitrogen and 17% carbon monoxide. Therefore, the gas is only

likely to support stable combustion at elevated temperature, or with a permanent

pilot flame. BFG may be ignited by a high ignition source such as a permanent pilot

flame. BFG may be ignited by a high ignition source such as a welding torch.

However, the resulting combustion is slow.

BFG is not typically considered an explosion hazard for the following reasons:

• Very high ignition energies are required to initiate BFG combustion;

• High concentration of inerts in the gas; and

• Very low combustion energy (3.2 MJ/m3).

Coke Oven Gas (COG)

COG is toxic and flammable gas and has a very strong odour. Its toxic properties

are due to the presence of CO (typically 9% v/v) in the gas. COG has a specific

gravity of 0.43 and therefore, is a very buoyant gas, which tends to disperse rapidly

when released to the atmosphere.




The high concentration of hydrogen and methane in COG suggests that the gas can

be ignited by a low ignition energy (e.g., static). Therefore, the probability of

ignition of COG leaks is likely to be high relative to other flammable gases.

COG is a corrosive gas due to the presence of hydrogen and sulphides (H2S=2500

mg/Nm3). This has significant implications for the maintainability of COG systems,

because COG pipework frequently develops small corrosion holes.

Carbon Monoxide

CO is a colourless, odourless gas, which is also flammable (limits 12% to 74%). It

has an auto-ignition temperature of 160˚C. It is a flammable gas with serious fire

hazard.

The health effects of CO are largely the result of the formation of

carboxyhemoglobin (COHb) which impairs the oxygen carrying capacity of the

blood. Resumption of the normal oxygen supply process takes place once the blood.

Resumption of the normal oxygen supply process takes place once an individual is

removed from the contaminated atmosphere. However, any damage due to the

prolonged loss of oxygen supply to the brain may not be reversible. The TLV, STEL

and IDLH values for CO is 50 ppm, 400 ppm and 1200 ppm respectively.

Liquified Petroleum Gas (LPG)

In addition to the BFG, COG and liquid oxygen, JSW-JSL will also use LPG. LPG is a

big fire and explosion hazard. Primarily, LPG is associated with the severe fire and

explosion hazards, i.e., boiling liquid expanding vapour explosion (BLEVE) under

sustained ignition and also vapour cloud explosion (VCE). BLEVE can be caused by

an external fire near the storage vessel causing heating of the contents and

pressure build-up. While tanks are often designed to withstand great pressure,

constant heating can cause the metal to weaken and eventually fail.

An unconfined (i.e., in open space) vapour cloud explosion (VCE) is possible only

when a large amount comes from a rupture of line/leak from large hole and

accumulates in the open space as a cloud while moving along the wind. If the

mixture of cloud and air is in the flammability range and some ignition source is

available on its way, it ignites and subsequently releases the energy on the point of

ignition in the form of a blast wave. It is called vapour cloud explosion (VCE). The

human injury and loss of property in case of VCE depends upon the mass involved

in the explosion and the location of the center of explosion.

A flammable release of gas that does not ignite at the leak source, or has a delayed

ignition, can produce a large vapour cloud, which covers a significant area. In the

absence of significant confinement or obstruction, ignition of the cloud results in a

low velocity flame front with minimal over pressure effects, known as a flash fire

and typically results (initially) only in impacts within the flammable cloud.

7.4.3 Identification of Major Hazard Installations Based on GOI Rules, 1989

Following accidents in the chemical industry in India over a few decades, a specific

legislation covering major hazard activities has been enforced by Govt. of India in




1989 in conjunction with Environment Protection Act, 1986. This is referred here as

GOI Rules 1989. For the purpose of identifying major hazard installations, the rules

employ certain criteria based on toxic, flammable and explosive properties of

chemicals.

A systematic analysis of the fuels/chemicals and their quantities of storage has been

carried out, to determine threshold quantities as notified by GOI Rules, 1989 and

the applicable rules are identified. Applicability of storage rules are summarized in

Table-7.6.

TABLE-7.6

APPLICABILITY OF GOI RULES TO FUEL/CHEMICAL STORAGE

Sr. No.

Chemical/ Fuel Listed in Schedule

Total Quantity

Threshold Quantity (T) for Application of Rules

5,7-9,13-15 10-12

1 Blast furnace gas (carbon

monoxide) 3(1)

2x50,000 m3

15 200


3(1) 2x50,000 m3

15 200

3 BOF gas (carbon monoxide)

3(1) 2x50,000 m3

15 200

4 LPG 3(1) 3x50 T 15 200

5 HFO 3(1) 2 x 1000 m3 25 MT 200 MT

6 LDO 3(1) 2x250 m3 25 MT 200 MT

7.5 Hazard Assessment and Evaluation

7.5.1 Methodology

An assessment of the conceptual design is conducted for the purpose of identifying

and examining hazards related to feed stock materials, major process components,

utility and support systems, environmental factors, proposed operations, facilities,

and safeguards.

7.5.2 Preliminary Hazard Analysis (PHA)

A preliminary hazard analysis is carried out initially to identify the major hazards

associated with storages and the processes of the plant. This is followed by

consequence analysis to quantify these hazards. Finally, the vulnerable zones are

plotted for which risk reducing measures are deduced and implemented. Preliminary

hazard analysis for fuel storage area and whole plant is given in Table-7.7 and

Table-7.8.

TABLE-7.7

PRELIMINARY HAZARD ANALYSIS FOR STORAGE AREAS

Unit Capacity Hazard Identified

Blast furnace gas (carbon monoxide)

1,00,000 m3 Toxic vapor cloud/ Vapour cloud explosive

Coke oven gas (hydrogen & methane )

1,00,000 m3 Toxic vapor cloud/ Vapour cloud explosive

BOF gas (carbon monoxide) 1,00,000 m3 Toxic vapor cloud/ Vapour cloud explosive

LPG 3 x 50 T BLEVE

HFO 2 x 1000 m3 Pool fire

LDO 2 x 250 m3 Pool fire




TABLE-7.8

PRELIMINARY HAZARD ANALYSIS FOR THE WHOLE PLANT IN GENERAL

PHA

Category Description of

Plausible Hazard

Recommendation Provision

Environmental

factors

If there is any

leakage and eventuality of source of

ignition.

-- All electrical fittings and

cables are provided as per the specified standards. All motor starters are

flame proof.

Highly

inflammable nature of the liquid fuels may cause fire hazard in the storage facility.

A well designed fire

protection including foam, dry powder, and CO2 extinguisher should be provided.

Fire extinguisher of small

size and big size are provided at all potential fire hazard places. In addition to the above, fire hydrant network is also provided.

7.5.3 Fire Explosion and Toxicity Index (FE&TI) Approach

Fire, explosion and toxicity indexing (FE & TI) is a rapid ranking method for

identifying the degree of hazard. The application of FE & TI would help to make a

quick assessment of the nature and quantification of the hazard in these areas.

However, this does not provide precise information.

The degree of hazard potential is identified based on the numerical value of F&EI as

per the criteria given below:

F&EI Range Degree of Hazard

0-60 Light

61-96 Moderate

97-127 Intermediate

128-158 Heavy

159-up Severe

By comparing the indices F&EI and TI, the unit in question is classified into one of

the following three categories established for the purpose (Table-7.9).

TABLE-7.9

FIRE EXPLOSION AND TOXICITY INDEX

Category Fire and Explosion Index (F&EI) Toxicity Index (TI)

I F&EI < 65 TI < 6

II 65 < or = F&EI < 95 6 < or = TI < 10

III F&EI > or = 95 TI > or = 10

Certain basic minimum preventive and protective measures are recommended for

the three hazard categories.




7.5.3.1 Results of FE and TI for Storage/Process Units

Based on the GOI Rules 1989, the hazardous fuel used by the proposed steel plant

is identified. Fire and explosion are the likely hazards, which may occur due to the

fuel storage. Hence, fire and explosion index has been calculated for in plant

storage. Estimates of FE&TI are given in Table-7.10.

TABLE-7.10

FIRE EXPLOSION AND TOXICITY INDEX

Sr. No.

Chemical/ Fuel Total Capacity F&EI Category TI Category

1 Blast furnace gas (carbon monoxide)

2 x 50,000 m3 53.29 I 13.61 III


2 x 50,000 m3 63.32 I 5.6 I

3 BOF gas (carbon monoxide)

2 x 50,000 m3 53.29 I 13.61 III

4 LPG 3 x 50 T 101.90 III 5.43 I

5 HFO 2 x 1000 m3 22.91 I 15.26 III

6 LDO 2 x 250 m3 19.82 I 9.55 II

7.5.4 Conclusion

Results of FE&TI analysis show that the storage of carbon monoxide gas, hydrogen

& methane gas, LPG, HFO and LDO falls in category of Light to moderate

category.

7.6 Consequence Analysis and Risk Assessment

7.6.1 Introduction

Consequences of worst-case/major credible emergency scenarios and likely dangers

to be associated in the proposed JSW-JSL plant near Barenda village have been

assessed through dispersion modeling, consequence and risk analysis.

Consequence analysis deals with the study of physical effects of potential dangers

associated with hazardous chemicals, their storage and operation etc. For

flammable and explosive chemicals like LPG, consequence on humans/animals and

structures are studied in terms of heat radiations and over pressures. For toxic

chemicals like carbon monoxide, consequence on human/animals are studied in

terms of concentration and dose-response relationships. The physical impact of heat

radiation, over pressure and toxic concentration are shown in Table-7.11.

The consequence modeling for different release scenarios for proposed JSW-JSL

plant has been carried out using the model ALOHA- “ Area Locations of Hazardous

Atmospheres” developed by NOHAA and USEPA. Aloha predicates the rate at which

chemical vapors may escape into the atmospheres from the leaking/ruptured tank.




TABLE-7.11(A)

DAMAGE DUE TO INCIDENT RADIATION INTENSITIES

Sr. No.

Incident Radiation (kW/m2)

Type of Damage Intensity

Damage to Equipment Damage to People

1 37.5 Damage to process equipment 100% lethality in 1 min. 1% lethality in 10 sec.

2 25.0 Minimum energy required to ignite wood at indefinitely long exposure without a flame

50% Lethality in 1 min. significant injury in 10 sec.

3 19.0 Maximum thermal radiation intensity allowed on thermally unprotected adjoining equipment

--

4 12.5 Minimum energy to ignite with a flame; melts plastic tubing

1% lethality in 1 min.

5 4.5 -- Causes pain if duration is longer than 20 sec, however blistering is un-likely (First degree burns)

6 1.6 -- Causes no discomfort on long exposures

Source: Techniques for Assessing Industrial Hazards by World Bank

TABLE-7.11(B)

EXPOSURE TIME NECESSARY TO REACH THE PAIN THRESHOLD

Radiation Level (kW/m2) Time to Pain Threshold (Seconds)

19.9 2

11.7 4

9.5 6

4.7 16

1.7 60

Source: Techniques for Assessing Industrial Hazards by World Bank

TABLE-7.11(C)

PHYSCIAL IMPACT OF EXPLOSION OVER PRESSURE

Pressure

(psig) Damage Produces by Blast

0.1 Breakage of small windows under strain

0.7 Minor damage to house structures

1.0 Partial demolition of houses

2 Partial collapse of walls and roofs of houses

3 Heavy machines (3000 lb) in industries building suffered little damage; steel frame building distorted

4 Cladding of light industries building ruptured

5 Wooden utility poles snapped; tall hydraulic press (40,000 lb) in building slightly damaged

7 Loaded train wagons overturned

10 Probable total destruction of buildings; heavy machines tools (7000 lb) moved and badly damaged

300 Limit of crater lip




TABLE-7.11(D)

PHYSICAL IMPACT OF TOXIC CONCENRATION

Concentration Level Observed Effect

Short-Tem Exposure Limit (STEL)

Maximum concentration of the substance to which workers can be exposed for a period upto 15 minutes without suffering (a) Intolerable irritation (b) Chronic or irreversible tissue change (c) narcosis of sufficient degree to increase accident proneness,

impair self rescue, or materially reduce worker efficiency, provided that no more than 04 excursion per day are

permitted, with at least 60 minutes between exposure periods, and provided that daily TLV is not exceeded.

Immediately Danger to Life and Health (IDLH)

An atmospheric concentration of any toxic, corrosive or asphyxiant substance that poses an immediate threat to life or

would cause irreversible or delayed adverse health effects or would interfere with an individual’s ability to escape from a dangerous atmosphere. If IDLH values are exceeded, all unprotected people must leave the area immediately.

Lethal Concentration at 50% mortality (LC50)

LC stands for “Lethal Concentration”. LC values usually refer to the concentration of a chemical in air but in environmental

studies it can also mean the concentration of a chemical in water. For inhalation experiments, the concentration of the chemical in air that kills 50% of the test animals in a given time (usually half to four hours) is the LC50 value

Fatal Level Death

7.6.2 Maximum Credible Loss Scenarios (MCLS)

As per MSIHC rules 1989 as amended in 2000, disaster management plan (DMP) for

any industry is prepared for worst-case release scenarios associated with maximum

damage potentials. The hazardous chemicals present in JSW-JSL are susceptible for

creating emergency scenarios and have been considered for assessing the damage

potentials through predicting the vulnerable zones and fatality/injured levels:

Blast furnace (BF) gas (carbon monoxide and hydrogen);

Coke oven (CO) gas (carbon monoxide and hydrogen);

LPG;

HFO; and

LDO.

7.6.3 Consequence Analysis of Accidental Release of Toxic Chemicals

The main toxic component of BF gas is carbon monoxide (CO) with maximum 25%

as basic composition. The IDLH and STEL values of CO are 1200 ppm and 400 ppm

respectively. These values represent the consequence zones of moderate and low

damage respectively. The severe level corresponding to 50% toxicity fatality level

has been considered as 3696 ppm for 20 minutes exposure duration with reference

to CO.

As per statutory regulation for the preparation of DMP, the worst-case scenario

involving the catastrophic release of entire quantity of a gasholder (BF/CO) is

considered, though the frequency of occurrence of worst-case scenario is very




remote. Such scenarios are considered in the assessment of likely dangers in and

around the plant with respect to the ultimate preparedness measures.

7.6.4 Meteorological Information for Consequence Analysis

During summer season, JSW-JSL area experiences maximum temperature about

43.4˚C with high surface winds and in winter months, the minimum temperature

reach about 9.7˚C. The relative humidity is in the range of 29.5% – 38.4% and

during rainy season, it may reach near 87%. The prevailing wind direction varies

with respect to season. The predominant wind direction is NW and SW with speed of

1 to 9 km/hr and the calm condition prevails for 7.8%.

Atmospheric conditions (wind speed, direction, solar radiation, cloud amount etc.) at

the time of release largely controls the extent of vulnerable zones. The physical

state of the atmosphere is usually best described by Pasquill-Gifford stability class A

(very unstable) to F (very stable). The details of various stability classes are given in

Table-7.12.

TABLE-7.12

PASQUILL-GIFFORD ATMOSPHERIC STABILITY CLASSES

Surface

Wind Speed

(at 10 m) in

m/s

Day Night

Incoming Solar Radiation Amount of over cast

Strong Moderate Slight >4/8 low

cloud

<3/8 low

cloud

<2 A A-B B

2-3 A-B B C E E

3-5 B B-C C D E

5-6 C C-D D D D

>6 C D D D D

The atmospheric characteristics of a particular site experience in general, almost all

types of stability classes during a season (summer, winter and rainy). For example,

in summer months, when the temperature is high for a sufficient amount of time, a

particular site like JSW-JSL near Barenda village may experience unstable (A/B

class) condition in noon time, neutral (D class) for majority of the time and also

stable condition (E/F) in the late night. In winter months, when the solar radiation is

weak to moderate with a considerable surface wind speed, the atmospheric

conditions may correspond to C/D class, E and F class in the late night and early

morning. However, the neutral class (D) of atmospheric condition exists for most of

the time in a day in a particular season; and hence it is considered as the most

representative class for a particular site and in a particular season (summer, rainy

or winter).

The other average meteorological parameters considered in the analysis are as

follows: ambient temperature = 38.5, relative humidity = 48, roughness parameter

= 0.17 (industrial area), three stability classes, i.e., B (unstable), D (neutral) and F

(very stable) class with wind speeds of 1.5 m/s to 2 m/s. For representative cases,

D class with wind speed of 2 m/s has been considered.




7.6.5 Flammable, Explosive and Toxicological Levels Considered

The following levels corresponding to severe, moderate and low damage levels have

been considered are given in Table-7.13(A) and Table-7.13(B).

TABLE-7.13(A)

TOXICOLOGICAL LEVELS CONSIDERED FOR CONSEQUENCE ANALYSIS

Vulnerable Zones Concentration (in ppm) and Damage

Levels considered for BF/CO gas

Red zone: severely affected zone 50% Fatality level (CCPS)=3696 ppm for 20 minutes exposure

Orange zone: moderately affected zone IDLH=1200 ppm for 30 minutes exposure

Yellow zone : low impact zone STEL=400 ppm for 1 minutes exposure

TABLE-7.13(B)

FLAMMABLE AND EXPLOSIVE LEVELS CONSIDERED FOR CONSEQUENCE ANALYSIS

Vulnerable Zones Radiation Intensity

(kW/m2) Levels for LPG

Explosion Overpressure (psi) Levels for LPG, CO and Hydrogen

Red zone: severely affected zone

37.5 (kW/m2) 7 psi

Orange zone: moderately

affected zone 12.5 (kW/m2) 3 psi

Yellow zone : low impact zone 4.5 (kW/m2) 1 psi

7.7 Selection of Scenarios in Gas Holders

7.7.1 Blast Furnace (BF) Gas Holder

The maximum volume (design capacity) of a BF gas holder is 50,000 m3. The

density of BF gas is 1.02 kg/m3, the total quantity of BF gas available in the

holder of volume 50,000 m3 is 51,000 kg. Out of this quantity, about 25 %, i.e.,

12,750 kg are CO. The maximum amount of hydrogen in BF gas is about 6% and

hence the contribution of hydrogen in the holder will be about 3060 kg. The

maximum values of temperature and pressure at the header are 35˚C and 350

mmwc.

The following worst-case release scenarios involving BF gasholder have been

conceptualized:

i) Accidental release of 12,750 kg of CO into the atmosphere leading to toxic

vapour cloud;

ii) Accidental release of 12,750 kg of CO into the atmosphere leading to

explosive vapour cloud; and

iii) Explosion associated with 3060 kg of hydrogen due to catastrophic release

of BF gas into the atmosphere from holder.




7.7.2 Coke Oven (CO) Gas Holder

The maximum volume (design capacity) of a CO gas holder is 55,000 m3. As the

density of CO gas is 0.43 kg/ m3, the total quantity of coke oven gas available in

the holder of volume 55,000 m3 us 23,650 kg. Out of this quantity, maximum 9

%, i.e., 2128 kg is CO. The maximum amount of hydrogen in CO gas is about 55

% and hence the contribution of hydrogen in the holder will be about 13007.5 kg.

The maximum values of temperature and pressure at the header are 35˚C and

343 mmwc.

The following worst-case release scenarios involving CO gasholder have been

conceptualized:

i) Accidental release of approximately 2128 kg of CO into the atmosphere (toxic

impact only);

ii) Accidental release of 2128 kg of CO into the atmosphere leading to explosive

vapour cloud; and

iii) Explosion associate with 13007.5 kg of hydrogen due to catastrophic release

of CO gas into the atmosphere from holder.

7.7.3 Fire and Explosion Associated with LPG Storage

In JSW-JSL, there will be one LPG bullet with capacity of 50 MT. LPG is a

colourless, tasteless and odourless gas. It has the ability to flash back, explode

within an enclosed space. It is a flammable gas, so it may be ignited from flames,

heat, sparks, static electricity and operational electrical switches. Thus, the use of

LPG within the JSW-JSL premise may lead to the occurrence of various scenarios.

Only the major scenarios of fire and explosion have been considered for the

consequence modeling to assess the maximum damage with the inventory of 45

MT (90 % full bullet).

i) Catastrophic failure of a LPG bullet (inventory=45 MT) leading to boiling liquid

expanding vapour explosion (BLEVE); and

ii) Catastrophic failure of a LPG bullet (inventory=45 MT) leading to vapour cloud

explosion (VCE).

7.7.4 Consequence Analysis Results for Toxic Carbon Monoxide in BF and CO Gas Holders

Though there are several incidences of gas holder fire and explosion resulting into

the release, the frequency of occurrence of such catastrophic release scenarios in

will vary as per the safety measures adopted in the unit. Carbon monoxide (CO)

has both toxicity and flammability/explosive nature. The consequence analysis

results in terms of maximum downwind distances due to accidental release of

BF/CO gas (equivalent CO) from holders under various atmospheric stability

conditions are shown in Table-7.14.

From the Table-7.12, worst case scenarios arising for toxic vapor cloud

catastrophic release from the holders (BF/CO) will have toxic impact upto 632 m

for CO holders and about 1100 m for BF gas holder respectively for IDLH

concentration level (1200 ppm) of CO under neutral stability class (D) and 2.0

m/s. The consequence distances will further increase upto a maximum distance of

about 1280 m if the release occurs in stable atmosphere (F class). Whereas, in




unstable atmospheric conditions (B class), the downwind distances will be the

least. The graphical representations of the consequence analysis of the carbon

monoxide are shown in Figure-7.3.

The flammability/explosive impact of CO released from BF/CO holders have been

studied in terms of extension of flammable impact under D; 2 m/s. The maximum

affected distance of 32 m of CO holder and 78 m of BF gas holder area.

TABLE-7.14

MAXIMUM IMPACT DISTANCES FOR TOXIC/FLAMMABLE VAPOUR CLOUD

OF CARBON MONOXIDE GAS FROM BF/CO GAS HOLDER

Sr. No

Scenario Wind Speed*/ Stability

Class

Toxic Vapour Cloud (maximum downwind distance in

m)

Vapour Cloud Explosion (maximum distance in

m)

3696 (ppm)

1200 (ppm)

400 (ppm)

0.7(psi) 1(psi) 2(psi)

1 Accidental release of 12750 kg of carbon monoxide (CO) into the atmosphere due to catastrophic failure of BF gas holder

2B 466 788 1200 82 78 73

2D 679 1100 1600 84 78 73

1.5F 696 1280 1900 93 86 82

2 Accidental release of 2128 kg of carbon monoxide (CO) into the atmosphere due to catastrophic failure of CO gas holder

2B 248 447 743 34 30 27

2D 360 623 994 36 32 28

1.5F 367 632 1000 43 39 36

*wind speed in m/sec




FIGURE-7.3(A)

ACCIDENTAL RELEASE OF CO INTO THE ATMOSPHERE LEADING TO

TOXIC VAPOR CLOUD

FIGURE-7.3(B)

ACCIDENTAL RELEASE OF CO INTO THE ATMOSPHERE LEADING TO

VAPOUR CLOUD EXPLOSION




7.7.5 Consequence Analysis Results for Fire/Explosion Scenario of Hydrogen as

Component of COG/BFG

One of the major flammable/explosive components of CO/BF gas is hydrogen.

Besides explosion, it may produce fireball type situation in the presence of ignition

source. Since hydrogen is very light, there is a chance of early ignition and less

possibility of explosion in late ignition. The maximum affected distances (m) for

fire and explosive scenarios of hydrogen under neutral stability class (D) and wind

speed of 2.0 m/s is given in Table-7.15 and Figure-7.4.

TABLE-7.15

VARIOUS SCENARIOS OF HYDROGEN

Scenarios Over pressure (psi) for Explosion (early

ignition)/Distance in meter

1 psi 3 psi 7 psi

Explosion associated with 3060 kg of hydrogen due to catastrophic release of BF gas into the atmosphere from

holder.

125 74 58

Explosion associate with 13007.5 kg of hydrogen due to catastrophic release of CO gas into the atmosphere from holder.

579 346 269

The vulnerable impact distances for explosion associated with hydrogen after

worst case release from BF/CO holder in terms of explosion overpressure levels

under D; 2 m/s for early ignition. Maximum impact distance corresponding to

moderate damage level of 3 psi for BF gas holder is 74 m and CO gas holder is

346 m from the holder area.

In addition, for planning purposes, the consequence impact zones

(severe/moderate/low) under stability class D, 2 m/s for the worst-case release

scenarios considered are depicted in plant layout of JSW-JSL. These drawings

show the locations and areas in JSW-JSL coming under severe/moderate/low

impact zones corresponding to various concentration levels of toxic vapour cloud

of hydrogen.




FIGURE-7.4(A)

EXPLOSION ASSOCIATED WITH HYDROGEN DUE TO CATASTROPHIC

RELEASE OF BF GAS INTO THE ATMOSPHERE FROM HOLDER

FIGURE-7.4(B)

EXPLOSION ASSOCIATED WITH HYDROGEN DUE TO CATASTROPHIC

RELEASE OF CO GAS INTO THE ATMOSPHERE FROM HOLDER




7.7.6 Consequence Results for Fire and Explosion Scenarios for LPG

Since the worst-case release scenario of LPG release are Boiling Liquid Expanding

Vapor Explosion (BLEVE) and unconfined Vapor Cloud Explosion (VCE), the impact

factors considered are radiation intensity and explosion overpressure. The three

heat radiation levels of 37.5 kW/m2, 12.5 kW/m2 and 4.5 kW/m2 and three

explosion overpressure levels of 7 psi, 3psi and 1 psi corresponding to severe

moderate and low damage levels have been considered respectively.

Maximum affected downwind distances (in m) due to heat radiation and explosion

over pressure level of LPG (stability class: D and wind speed =2.0 m/s)

BLEVE/Fire ball scenarios are given in Table-7.16 and Figure-7.5.

TABLE-7.16 (A)

THERMAL RADIATION LEVELS DUE TO

FAILURE OF LPG BULLET

Scenario

Thermal Radiation Intensities in kW/m2

/Distance in m

37.5 kW/m2 12.5 kW/m2 4.5 kW/m2

BLEVE due to catastrophic failure of a LPG Bullet (45 MT)

213 396 659

TABLE-7.16 (B)

EXPLOSIVE OVER PRESSURE LEVELS DUE TO


Scenario

Explosion Overpressure Level in psi

/Distance in m

1 psi 3 psi 7 psi

Vapour cloud explosion due to catastrophic rupture of LPG bullet (45 MT)

926 784 Never reached LOC

7.7.7 Consequence Analysis Results for Pool Fire Scenario for HFO and LDO Storage

Tanks

The maximum capacity of storage of HFO and LDO are 2x1000 KL and 2X 250 KL

respectively. The most credible failure is the rupture/hole of the storage tank. As

a worst case, it is assumed that the entire contents leak out into the dyke

forming a pool, which may catch fire on finding a source of ignition. The radiation

intensities for rupture of HFO and LDO storage tank is given in Table-7.17 and

Figure-7.6.

TABLE-7.17

THERMAL RADIATION DUE TO FAILURE OF HFO AND LDO TANKS

Scenario Thermal Radiation kW/m2 /distances in m

37.5 12.5 4.5

Failure of HFO storage tank

16 35 63

Failure of LDO storage tank

<10 13 25




FIGURE-7.5(A)

THERMAL RADIATION LEVELS DUE TO


FIGURE-7.5(B)

EXPLOSIVE OVER PRESSURE LEVELS DUE TO





FIGURE-7.6(A)

THERMAL RADIATION DUE TO FAILURE OF HFO TANKS

FIGURE-7.6(B)

THERMAL RADIATION DUE TO FAILURE OF LDO TANKS




7.7.8 Coal Handling Plant - Dust Explosion

Coal dust when dispersed in air and ignited would explode. Crusher house and

conveyor systems are most susceptible to this hazard. To be explosive, the dust

mixture should have:

Particles dispersed in the air with minimum size (typical figure is 400

microns);

Dust concentrations must be reasonably uniform; and

Minimum explosive concentration for coal dust (33% volatiles) is 50 gm/m3.

Failure of dust extraction and suppression systems may lead to abnormal

conditions and may increase the concentration of coal dust to the explosive limits.

Sources of ignition present are incandescent bulbs with the glasses of bulkhead

fittings missing, electric equipment and cables, friction, spontaneous combustion

in accumulated dust. Dust explosions may occur without any warnings with

maximum explosion pressure upto 6.4 bar. Another dangerous characteristic of

dust explosions is that it sets off secondary explosions after the occurrence of the

initial dust explosion. Many a times the secondary explosions are more damaging

than primary ones. The dust explosions are powerful enough to destroy

structures, kill or injure people and set dangerous fires likely to damage a large

portion of the coal handling plant including collapse of its steel structure which

may cripple the life line of the steel plant.

Stockpile areas shall be provided with automatic garden type sprinklers for dust

suppression as well as to reduce spontaneous ignition of the coal stockpiles.

Necessary water distribution network for drinking and service water with pumps,

piping, tanks, valves etc., will be provided for distributing water at all transfer

points, crusher house, control rooms etc. A centralized control room with

microprocessor based control system (PLC) has been envisaged for operation of

the coal handling plant. Except for locally controlled equipment like traveling

tripper, dust extraction/ dust suppression / ventilation equipment, sump pumps,

water distribution system etc., all other in-line equipment will be controlled from

the central control room but will have provision for local control as well. All

necessary interlocks, control panels, MCC’s, mimic diagrams etc. will be provided

for safe and reliable operation of the coal handling plant.

7.7.8.1 Control Measures for Coal Yards

The total quantity of coal will be stored in separate stock piles, with proper drains

around to collect washouts during monsoon season.

Water sprinkling system will be installed on stocks of coal in required scale to

prevent spontaneous combustion and consequent fire hazards. The stock

geometry will be adopted to maintain minimum exposure of stock pile areas

towards predominant wind direction.

7.7.9 Identification of Hazards

The various hazards associated, with the plant process apart from fuel storage have

been identified and are outlined in Table-7.18.




TABLE-7.18

HAZARD ANALYSIS FOR PROCESS IN THE PLANT

Sr. No. Blocks/Areas Hazards Identified

1 Coal storage in open yard Fire, spontaneous combustion

2 Coal handling plant

including bunker area

Fire and/or dust explosions

3 Boilers

Fire (mainly near oil burners), steam explosions, fuel explosions

4 Steam turbine generator buildings

Fires in – a) Lube oil system b) Cable galleries c) Short circuits in i) Control rooms ii) Switch-gears Explosion due to leakage of hydrogen and fire

following it.

5 Switch-yard control room Fire in cable galleries and switch-gear/control room

6 LDO & HSD tank farms Fire

7.7.10 Hazardous Events with Greatest Contribution to Fatality Risk

The hazardous event scenarios likely to make the greatest contribution to the risk

of potential fatalities are summarized in Table-7.19. ‘Onsite facility’ refers to the

operating site at Barenda village, whereas ‘offsite facility’ refers to transport and

handling systems, which are away from the operating site.

TABLE-7.19

HAZARDOUS EVENTS CONTRIBUTING TO ON-SITE FACILITY RISK

Hazardous Event Risk Rank Consequences of Interest

Onsite vehicle impact on personnel

3 Potential for single fatalities, onsite impact only

Entrapment/struck by machinery

3 Potential for single fatalities, onsite impact only

Fall from heights 3 Potential for single fatalities, onsite impact

only

Electrocution 3 Potential for single fatalities, onsite impact

only

Storage tank rupture 3 Potential for single fatalities, onsite impact

only

7.7.11 Risk Assessment Summary

The preliminary risk assessment has been completed for the proposed plant and

associated facilities and the broad conclusions are as follows:

There will be no significant adverse community impacts or environmental

damage consequences; and




The hazardous event scenarios and risks in general at this facility can be

adequately managed to acceptable levels by performing the recommended

safety studies as part of detailed design, applying recommended control

strategies and implementing a safety management system.

7.7.12 Risk Reduction Opportunities

The following opportunities will be considered as a potential means of reducing

identified risks during the detailed design phase:

Buildings and plant structures designed for cyclone and seismic events (where

appropriate), to prevent structural collapse and integrity of weather (water)

proofing for storage of dangerous goods;

Provision for adequate water capacity to supply fire protection systems and

critical process water;

Isolate people from load carrying/mechanical handling systems, vehicle traffic

and storage and stacking locations;

Installation of fit-for-purpose access ways and fall protection systems to

facilitate safe access to fixed and mobile plant;

Provision and integrity of process tanks, waste holding tanks and bunded

areas as per relevant standards;

Containment of hazardous materials;

Security of facility to prevent unauthorized access to plant, introduction of

prohibited items, and control of onsite traffic; and

Development of emergency response management systems commensurate

with site specific hazards and risks (fire, explosion, rescue and first aid).

****

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