oil industry safety directorate - oisd.gov.in

Page no I

S. No.: OISD/DOC/2007/2017/01

OIL INDUSTRY SAFETY DIRECTORATE

एयर-हाइड्रोकाबबन मिश्रण और पायरोफोररक पदाथों की सरुक्षऺत हैंडमऱ िंग

ओ आई एस डी–िानक -112

SAFE HANDLING OF AIR-HYDROCARBON

MIXTURES AND PYROPHORIC SUBSTANCES

OISD-STANDARD-112

Prepared by

FUNCTIONAL COMMITTEE ON

SAFE HANDLING OF AIR-HYDROCARBON MIXTURES

AND PYROPHORIC SUBSTANCES

FOR RESTRICTED CIRULATION ONLY

OIL INDUSTRY SAFETY DIRECTORATE

Government of India

Ministry of Petroleum & Natural Gas 8

th Floor, OIDB Bhavan, Plot No. 2, Sector – 73, Noida – 201301 (U.P.)

Website: https://www.oisd.gov.in Tele: 0120-2593833, Fax: 0120-2593802

Inception 1989

Amendment Edition July 1999

Amendment Edition October 2002

Revised Edition 2019

http://www.oisd.gov.in/

Page no II

PREAMBLE

Indian Petroleum Industry is the energy lifeline of the nation and its continuous performance is

essential for growth and prosperity of the country. As the industry essentially deals with inherently

inflammable, hazardous and toxic substances throughout its value chain – upstream, midstream

and downstream – Safety is of paramount importance to this industry as only safe performance at

all times can ensure optimum Return on investment of these national assets and resources

including sustainability.

While statutory organizations were in place all along to oversee safety aspects of Indian Petroleum

Industry, Oil Industry Safety Directorate (OISD) was set up in 1986 by Ministry of Petroleum and

Natural Gas, Government of India as a knowledge centre for formulation of updated world-scale

standards for design, layout and operation of various equipment, facility and activities involved in

this industry. Moreover, OISD was also given responsibility of monitoring implementation status of

these standards through safety audits.

In more than three decades of its existence, OISD has developed a rigorous, multi-layer, iterative

and participative process of development of standards – starting with research by in-house experts

and iterating through seeking & validating inputs from all stake-holders – operators, designers,

national level knowledge authorities and public at large – with a feedback loop of constant updating

based on ground level experience obtained through audits, incident analysis and environment

scanning.

The participative process followed in standard formulation has resulted in excellent level of

compliance by the industry culminating in a safer environment in the industry. OISD – except in

the Upstream Petroleum Sector – is still a regulatory (and not a statutory) body but that has not

affected implementation of the OISD standards. It also goes to prove the old adage that self-

regulation is the best regulation. The quality and relevance of OISD standards had been further

endorsed by their adoption in various statutory rules of the land.

Petroleum Industry in India is significantly globalized at present in terms of technology content

requiring its operation to keep pace with the relevant world scale standards & practices. This

matches the OISD philosophy of continuous improvement keeping pace with the global

developments in its target environment. To this end, OISD keeps track of changes through

participation as member in large number of International and national level Knowledge

Organizations – both in the field of standard development and implementation & monitoring in

addition to updation of internal knowledge base through continuous research and application

surveillance, thereby ensuring that this OISD Standard, along with all other extant ones, remains

relevant, updated and effective on a real time basis in the applicable areas.

Together we strive to achieve NIL incidents in the entire Hydrocarbon Value Chain. This, besides

other issues, calls for total engagement from all levels of the stake holder organizations, which we,

at OISD, fervently look forward to.

Jai Hind!!

Executive Director

Oil Industry Safety Directorate

Page no III

FOREWORD

The Oil Industry in India is over 100 years old. As such, various practices have been in vogue

because of collaboration/ association with different foreign companies and governments.

Standardization in design philosophies, operating and maintenance practices remained a grey

area. This coupled with feedback from some serious accidents that occurred in the past in India

and abroad, emphasized the need for the industry to review the existing state-of-the-art in

designing, operating and maintaining of Oil and Gas installations.

With this in view, the Ministry of Petroleum & Natural Gas, in 1986, constituted a Safety Council

assisted by Oil Industry Safety Directorate (OISD), staffed from within the industry, in formulating

and implementing a series of self-regulatory measures aimed at removing obsolescence,

standardising and upgrading the existing standards to ensure safer operations. Accordingly,

OISD constituted a number of Functional Committees of experts nominated from the industry to

draw up standards and guidelines on various subjects.

The present document on Safe Handling of Air-Hydrocarbon Mixtures and Pyrophoric Substances

was prepared, by the Functional Committee on Process Design and Operating Philosophies. This

document is based on the accumulated knowledge and experience of industry members and the

various national and international codes and practices, is meant to be used as a supplement and not

as a replacement for existing codes standards and manufacture's recommendations.

The figures and annexures used in the document are representative in nature.

We, at OISD, are confident that the provisions of this standard, when implemented in totality, would

go a long way in ensuring safe operation of the target group of locations.

Needless to mention, this standard, as always would be reviewed based on field level experience,

incident analysis and environment scanning. Suggestions from all stake holders may be forwarded

to OISD.

Page no IV

NOTE

Oil Industry Safety Directorate (OISD) publications are prepared for use in the Oil and Gas industry

under Ministry of Petroleum and Natural Gas. These are the property of Ministry of Petroleum and

Natural Gas and shall not be reproduced or copied and loaned or exhibited to others without written

consent from OISD.

Though every effort has been made to assure the accuracy and reliability of data contained in these

documents, OISD hereby expressly disclaims any liability or responsibility for loss or damage

resulting from their use.

These documents are intended only to supplement and not to replace the prevailing statutory

requirements of Government body which must be followed as applicable.

Where ever Acts/ Rules/ Regulation and National/ International Standards are mentioned in the

standard, same relates to in-vogue version of such documents.

Page no V

FUNCTIONAL COMMITTEE OF SECOND EDITION

ON

SAFE HANDLING OF AIR-HYDROCARBON MIXTURES AND PYROPHORIC

SUBSTANCES

List of Members (2018)

NAME ORGANISATION

LEADER

Sh. B Behari. Indian Oil Corporation Limited, RHQ

MEMBERS

Sh. P S Rao Hindustan Petroleum Corporation Limited ,CO

Sh. Pallab Das Numaligarh Refinery Limited,

Sh. Rohit Sood Reliance Industries Limited, Jamnagar

Sh. Ramdular Paswan Bharat Petroleum Corporation Limited – Mumbai Refinery

Sh. Roshan Shihab Bharat Petroleum Corporation Limited – Kochi Refinery

Sh. Praveen Kumar Indian Oil Corporation Limited, NRPL

Sh. P K Sarma Oil Industry Safety Directorate, Noida

MEMBER CO-ORDINATOR

Sh. Harendra Yadav Oil Industry Safety Directorate, Noida

In addition to the above several experts from industry contributed in the preparation, review and

finalisation of the document.

Sh. Y V N Trinath Indian Oil Corporation Limited, HO, Mumbai

Page no VI

FIRST COMMITTEE

ON

PROCESS DESIGN AND OPERATING PHILOSOPIES

List of Members

LEADER

Sh. W. D. Lande Hindustan Petroleum Corporation Limited

Sh. V.S. Save Hindustan Petroleum Corporation Limited

Sh. G. Raghunathan, Hindustan Petroleum Corporation Limited

Sh. S.V. Puthli Hindustan Petroleum Corporation Limited

Sh. N. Lal Oil & Natural Gas Corporation

Sh. N.N. Gogoi Oil India Limited

Sh. M.A. Sreekumar CRL

Sh. A. Varadarajan MRL

Sh. B.K. Trehan Oil Industry Safety Directorate, Noida

In addition to the above several experts from industry contributed in the preparation, review and

finalisation of the document.

NAME ORGANISATION

MEMBERS

MEMBER CO-ORDINATOR

Page no VII



CONTENTS

Section Description Page No.

1.0 Introduction 1

2.0 Scope 1

3.0 Definition 1

4.0 Elements of Fire 2

5.0 Prevention of Explosive Gas Mixture 4

5.1 Sources of Entry of Oxygen 4

5.2 Elimination of Oxygen 5

5.2.1 During Unit Start-up 5

5.2.2 Inert Gas 5

5.2.3 Vacuum Systems 5

5.2.4 Flare header 5

5.2.5 LPG tank lorries and wagons 6

5.2.6 Filing of new /repaired LPG Cylinders 6

5.3 Elimination of Hydrocarbons 6

5.3.1 During unit shut-down 6

5.3.2 Furnace lighting 6

5.3.3 Leaks and spills 7

5.3.4 Blowdown system 7

5.3.5 Depressurisation of LPG/ Gas from system 7

5.3.6 Air blowing of hydrocarbon lines 7

5.4 Precautions in Processes using Air 8

6.0 Pyrophoric Substances 8

6.1 Sources of hazards 8

6.2 Precautions and safety measures 9

6.3 Triethylaluminum (TEAL)

10

6.3.1 Sources and Hazards of TEAL

10

6.3.2 Precautions and safety measures

10

7.0 References 12

Annexure-I 13

(MSDS of TEAL )

Page no VIII

OISD – STD – 112 Page No. 1





1.0 INTRODUCTION

Most of the refined petroleum products are used as sources of heat energy by combustion with air in

engines or heaters. The same type of combustion can occur on a larger scale in petroleum refining or

handling units with disastrous effects, if air mixes with petroleum fractions in the wrong place and in

right proportions. Process units which use air for regeneration or reaction, provide many opportunities

for forming flammable combinations of air and hydrocarbon mixtures. Hence, the handling of air and

hydrocarbons should be done in a safe manner to prevent the formation of flammable mixtures which

can cause a disaster.

Also there are some substances which catch fire spontaneously when exposed to air under atmospheric

conditions. These are basically compounds of iron sulphides and are known as Pyrophoric substances.

The Pyrophoric character depends upon the chemical reactivity of the substance and the physical

condition of the surface. It can also be affected by the presence of foreign materials which may

catalyse the thermal characteristics of the substance.

2.0 SCOPE

The purpose of this document is to provide relevant technical standards for reducing fire hazards of air

hydrocarbon mixtures and pyrophoric substances. The document also illustrates the nature and origin

of air hydrocarbon mixtures and pyrophoric substances. The document is applicable to petroleum

production, refining, petrochemical, Gas Processing Plants (GPP), pipelines and marketing

installations.

3.0 DEFINITIONS

Shall: Indicates provisions that are mandatory.

Should: Indicates a recommendation or that which is advised but not mandatory.

Combustion: A chemical process of oxidation that occurs at a rate that is fast enough to produce heat

and usually light, in the form of either a glow or flames.

Burning Velocity: The rate of flame propagation relative to the velocity of the unburned gas that is

ahead of it.

Flammable Mixture.: A mixture of fuel, oxygen (or other oxidant) and inert gases that has a

composition in the flammable range.




Flammable Limits: The minimum and maximum concentrations of a combustible material, in a

homogeneous mixture with a gaseous oxidizer, that will propagate a flame.

Flammable Range :. The range of concentrations between the lower and upper flammable limits.

Lower Explosive Limit (LEL): Is the minimum concentration of a vapor in air (or other oxidant) below

which propagation of flame does not occur on contact with an ignition source. This is usually expressed

as volume percentage of the vapor in air. This is also referred as Lower Flammable Limit (LFL).

Upper Explosive Limit (UEL): Is the maximum concentration of a vapor in air (or other oxidant) above

which propagation of flame does not occur on contact with and ignition source. This is usually

expressed as a volume percentage of vapors in air. This is also referred as Higher Flammable Limit

(HFL).

Inert Gas: A nonreactive, non-flammable, noncorrosive gas such as argon, helium, krypton, neon,

nitrogen, and xenon.

Fuel:. A material that will maintain combustion under specified environmental conditions.

Gas: The state of matter characterized by complete molecular mobility and unlimited expansion; used

synonymously with the term vapor.

Vent: An opening in the enclosure to relieve the developing pressure from a deflagration.

Purge: To free a gas conduit of air or gas, or a mixture of gas and air.

Pyrophoric Material: A substance capable of self-ignition on short exposure to air under ordinary

atmospheric conditions. The pyrophoric substance ignites spontaneously in air at or below 55 °C.

TEAL: Triethylaluminum (TEAL) is highly reactive, reacting explosively with water and igniting

spontaneously on contact with air (pyrophoric).

Auto Ignition: The auto-ignition point is the lowest temperature at which the material will ignite by itself

in contact with oxygen / air without any source of ignition.

4.0 ELEMENTS OF FIRE

All fires have three constituents viz. combustible substances like hydrocarbon, hydrogen etc., air or

oxygen which should be present in the right proportions and a source of ignition. If any one of the three

constituents is removed, fire can not occur. Therefore, it is important to prevent the combination of

these constituents by eliminating any one of them at all times.




Hydrocarbon at temperature above it’s auto-ignition point or pyrophoric substances like iron sulphide,

TEAL etc. will ignite by itself without any source of ignition. Hence, the contact of oxygen / air to these

materials available at and above their auto-ignition temperatures should be eliminated.

The hydrocarbon and air present in the right proportions means that the concentration of hydrocarbon

in air is between the explosive limits. Hydrocarbons have two explosive limits , the Lower Explosive

Limit (LEL) i.e. the lowest concentration of the hydrocarbon present in air hydrocarbon mixture below

which the mixture will not ignite and the Higher/Upper Explosive Limit (HEL/UEL) i.e. the highest

concentration of the hydrocarbon present in the air-hydrocarbon mixture above which the mixture will

not ignite.

The explosive limits and auto-ignition temperatures of some commonly handled flammable liquids,

gases and solids are listed in Table 1. These flammability limits are valid only under atmospheric

conditions. The range of explosive limit is wider at higher pressure and temperature or in oxygen rich

environment instead of air.

TABLE 1

AUTO-IGNITION TEMPERATURES AND EXPLOSIVE LIMITS

---------------------------------------------------------------------------------------------------------------------------------------

Material Explosive limits Auto-ignition

% volume in air Temperature

------------------------------------ -------------------------------

Lower Higher Deg.C

---------------------------------------------------------------------------------------------------------------------------------------

Carbon Monoxide 15.7 70.9 610

Hydrogen 9.5 65.2 530

Acytelene 2.4 52.3 335

Hydrogen Sulfide 4.3 45.5 260

Methane 6.3 11.9 645

Ethylene 4.0 28.6 540

Propylene 4.2 9.5 530

Cyclopropane 2.4 10.4 497

Propane 2.4 9.5

Natural Gas 9.8 24.8 450

Butadiene 1-3 2.0 11.5

n-Butylene 1.8 12.0

i-B utane 1.8 8.4

n-Butane 1.9 11.5 490

Methyl Ethyl ketone 1.81 11.5 404

Methyl n-butyl ketone 1.22 8.0

n-Pentane 1.3 4.9 309

Benzol 1.4 8.0 580

Cyclohexane 1.31 8.35

n-Hexane 1.3 8.6 487

Toluene 1.0 7.3 810




Styrene 1.1 6.1 490

n-Heptane 1.0 6.0 233

o- Xylene 1.0 5.3 496

n-Octane 0.84 3.2 232

n-Nonane 0.74 2.9 ---

n-Decane 0.6 5.4 463

Petroleum ether 1.4 5.9 246

Stoddard’s solvent 1.1 6.0 232-260

Gasoline (Typical) 1.3 6.0 350

Kerosene (Typical) 1.16 6.0 325

Lubricating oil,

spindle (Typ) -- --- 248

Lubricating oil,

cylinder )Typ.) -- --- 417

Asphalt (Typical) -- --- 280

Reduced Crude (Typical) --- -- 300

----------------------------------------------------------------------------------------------------------------------------------

(Reference: Most of the data has been taken from Petroleum Refinery Engineering by W.L.

Nelson and Lange’s Handbook on Chemistry to be revisit)

Sources of Ignition:

Cutting and welding sparks, burning metal from grinding jobs, an active oxyacetylene/ Argon torch,

static electricity related voltage, hammering, electrical connections /appliances, vehicle exhaust, a

glowing cigarette butt, match box, lighter etc. are well known sources of ignition.

Beside pyrophoric substances, the other invisible ignition sources are ,

Many in-compatible chemicals when react, they may get hot enough to ignite and start fire.

Unstable chemicals like peroxide when stored above its decomposition temperature.

Enhanced oxidation by increased surface area, for example, activated carbon plus organic

vapors , oily rags, or combustible liquids leaked into insulation etc (CH4 fire also called minch

fire)

Vigilant approach with proper precautions/ and measures in the areas mentioned above ensures

elimination of such ignition sources.

5.0 PREVENTION OF EXPLOSIVE GAS MIXTURES

5.1 SOURCES OF ENTRY OF OXYGEN

Elimination of air/oxygen from any system in the plants is an essential requirement to prevent a fire

hazard. Oxygen can be present in the system containing hydrocarbons or enter through any of the

typical sources, examples given below :

i) Atmospheric air leakage through open or defective valves and flanges in vacuum systems




ii) Atmospheric air entering open lines and vessels.

iii) Atmospheric air associated with process or wash water.

iv) Atmospheric air entering open equipment when internal pressure or level is lowered.

v) Compressed air used in line blowing.

vi) Compressed air used for agitation.

vii) Oxygen or air in solution in feedstock.

viii) Oxygen or air used in oxidation processes.

ix) Oxygen contamination of nitrogen/inert gas or other compressed gases used for purging or

processing.

5.2 ELIMINATION OF OXYGEN

5.2.1 During Unit Start Up

To ensure safe start up of a unit, it is most important to remove the air from the system by purging or

evacuation, before hydrocarbons are introduced. All the air shall be purged with inert gas, steam, water

etc. and the system should be tested free of oxygen (i.e. less than 0.5% vol.). Analysers/laboratory

testing is to be done when purging is carried out through inert gas. In case of steam purging , sufficient

time should be given as per standard procedure by maintaining positive/ adequate system pressure.

In case of water flushing , over flow is to be carried out as per standard procedure. Systems once

purged shall be kept under positive pressure with the purging medium or fuel gas as required by the

service of the equipment, after it is proved to have no leak.

5.2.2 Inert Gas:

It is not uncommon that inert gases, used for purging operations, contain more than maximum

allowable oxygen content (i.e 0.5% vol). Hence, periodical analysis of the inert gas shall be done to

ensure that the system being purged with the inert gas, is operating within the tolerable limit of oxygen

content. During plant start-up/ shutdown where process system requires inertisation, inert gas should be

checked for O2 content before using.

5.2.3 Vacuum Systems:

Systems working under vacuum conditions can pull in air through leaky flanges, pump glands/seals, left

open vents and drains, etc. Vacuum system shall be tested and checked thoroughly, for leaks and

tightness, before start-up and periodically during operation. Also a sample point of the exhaust gases

from the ejector system/ hot well shall be analysed periodically for oxygen content and there should be

an O2 analyser on off-gas line from hot well for proper monitoring of O2 ingress into the vacuum




column/system during normal operations. Critical flanges of vacuum column (such as flash zone )

should be torque tightened.

5.2.4 Flare Headers:

The flare header shall always be maintained at minimum positive pressure to prevent entry of air into

flare system. Gases entering the flare header, shall not contain oxygen (e.g. off gases ex Merox

oxidiser that are routed to flare). An online Oxygen analyser shall be provided with an alarm and

interlock system to shut-off the off gas to flare from Merox Oxidizer in case of high oxygen content .

Positive isolation of CBD system to flare shall be ensured during M & I.

5.2.5 Tank Lorries and Wagons(LPG/Propane/Propylene etc.):

At times, tank lorries/wagons used for transporting LPG/ Propane/Propylene are taken out of service

temporarily for maintenance or switching to alternate service. Before taking them back on intended

service, it shall be ensured that the containers are purged so as to lower the oxygen content below

0.5% volume.

At all tank lorry/wagon loading locations, the oxygen content in tank lorries and wagons shall be

checked before loading after maintenance work has been carried out on the TL/TW or when the

pressure gauge on TL/TW reads less than 1_atm_ abs. In case, the receiving vessel is having a

pressure of less than 1 Kg/sq.cm.abs, it shall not be filled.

If oxygen content is greater than 0.5% (vol.), then the tank lorry or wagon shall be evacuated and

purged out with inert gas and vented out to atmosphere at a safe location until the oxygen content is

0.5% (vol.) or less. Water can also be used in place of inert gas. Wherever water is used for

displacing air from the tank lorries/wagons, it should be provided with a bottom drain to facilitate

complete removal of water which would otherwise cause corrosion and product contamination.

5.2.6 Filing of New/Repaired LPG Cylinders:

The cylinders should be evacuated to an absolute pressure of 0.35 kg/cm2 abs maximum before filing

with LPG. Alternatively nitrogen or inert gas should be used to purge oxygen from cylinders before

filling with LPG. ( refer OISD-STD-144)

5.3 ELIMINATION OF HYDROCARBONS

5.3.1 During Unit Shut Down:

During shut down it shall be ensured that hydrocarbons are thoroughly purged off with steam or inert

gas such that the hydrocarbon content in the equipment is below the lowest LEL of the hydrocarbons

present and system is positively isolated by blinds to prevent re-entry of any hydrocarbons.

During steaming or purging , it shall be ensured that all the system / piping loops including bypass

/instrument loops are included for complete hydrocarbons/Chemicals flushing/elimination.




Chemical cleaning and decontamination process is deployed during planned shutdowns for effective

removal of hydrocarbons from equipment and pipelines to facilitate safe inspection and maintenance.

Various types of chemicals are used in this process as cleaners and inhibitors. After the process, it has

to be ensured that all the chemicals are thoroughly flushed out from system including all the loops as

per the standard procedure. The products of chemical cleaning shall be routed to designated tanks and

suitable processing / neutralizing shall be ensured before disposing off.

5.3.2 Furnace Lighting:

Before lighting up the burners, the furnace shall be purged as per standard operating procedure to

remove any hydrocarbon vapours and gases in the firebox.

Burner management system should be deployed to monitor and control fuel burning during start-up,

shutdown and normal operation.

5.3.3 Leaks and Spills:

In case of light hydrocarbons, leakage from drains and vents shall be arrested immediately to prevent

vapour cloud formation. Drains and vents of equipment on light hydrocarbon service shall be provided

with double block valves and capping/end blinded. Single block valve with capping/end blinding shall

be provided only on those circuits, which are operated during turn around. However, end flanges with

blinds are preferred over capping .

5.3.4 Blowdown System:

The drains of closed equipment (viz.: pumps, heat exchangers, etc.) handling light distillates in the

range of C5-140 Deg. C shall be routed through a closed blowdown system to prevent formation of

explosive mixtures. An alternative open drain with double block valve and blind should be provided

for physical checking . This shall be operated after the equipment has been depressurised , isolated

(by valves) and drained to the closed blowdown.

The requirements of the above drain provisions and operating philosophy is applicable for all the

hydrocarbon streams in the processing unit.

5.3.5 Depressurisation of LPG/ Gas from system:

Depressurization of LPG / Gas shall not be done to open atmosphere. It shall be suitably routed to a

flare system . In the absence of such provisions, vent pipes fitted with flash back arrestor / flame

arrestor shall be provided to carry the vented streams to a safe distance and release at a height not

less than 1.5 m above the eaves of the structure ( Refer OISD-STD-144).

5.3.6 Air Blowing of Hydrocarbon Lines:




Air blowing of hydrocarbon lines in closed system results in increase in pressure. This may increase the

temperature & flammability range and decrease the auto-ignition temperature. This situation may result

into an internal combustion leading to occurrence of explosion.

To prevent such possibilities, air blowing of hydrocarbon lines shall be done subject to following

conditions:

i. Pipelines on lube oil service - if oil temperature is below 93 Deg. C and flash point of oil is above

121 Deg. C.

ii. Pipelines on reduced crude and heavy oil service - if oil temperature does not exceed 93 Deg. C

iii Pipelines on asphalt service - if asphalt temperature does not exceed 204 Deg. C

Air blowing of pipelines leading into closed vessels/flare and tanks shall not be done. Such lines shall

be positively isolated/disconnected before air blowing.

5.4 PRECAUTIONS IN PROCESSES USING AIR.

In processes, like regenerative type Catalytic Cracking, Reforming, Bitumen Blowing and other

processes requiring air, the addition of air should be carefully controlled such that the off gases from

the process does not contain oxygen more than 0.5% volume. Adequate safeguards should be

provided to ensure that there is no undesirable uncontrolled reactions, explosions and other unsafe

conditions. Standard operating procedure as per the unit shall be followed in integration with rest of

the plant.

In treating plant, where hydrocarbons like LPG, Gasoline and Kerosene are treated catalytically in

presence of air, it is usually possible to operate with only that amount of air which will remain dissolved

in the liquid. Protective measures in such operations shall include a careful tie-in between hydrocarbon

feed and oxygen supply rate to prevent the formation of an explosive mixture. Design and layout of

vessel and piping should eliminate pockets where vapour can accumulate. As per process criticality,

Oxygen analyzer (s) should be provided at suitable location.

6.0 PYROPHORIC SUBSTANCES

6.1 SOURCES AND HAZARDS

Pyrophoric Material is capable of self-ignition on short exposure to air under ordinary atmospheric

conditions. The pyrophoric substance ignites spontaneously in air at or below 55 °C.

In Oil and Gas industry, the major source of pyrophoric substance is iron sulphide. Pyrophoric iron

sulphide is a corrosion product that may form when iron oxide (rust) reacts with sulphur:

Fe2O3 + 3H2S 2FeS + 3H2O + S




These substances may form on the walls of vessels, tanks, towers, pipes, flare headers, pump strainers

etc. which contain or handle hydrocarbon containing sulphur compounds (viz. hydrogen sulphide,

mercaptan, etc.) and aromatic tar. It also gets deposited in the sludge or tank bottom wastes.

When pyrophoric substances come in contact with air, they react with the oxygen generating heat.

4FeS + 3O2 2Fe2O3 + 4S + Heat

If the heat is not dissipated, the temperature would rise high enough to ignite a flammable mixture in or

around the deposits.

In tanks and vessels having vents open to atmosphere, iron sulphide formed is normally converted to

iron oxide scale, generating little heat which gets dissipated immediately and hence does not pose any

potential hazard. But in gas blanketed tanks or equipment where little or no air is present, large

quantities of the iron sulphides may remain in sulphide form. If such equipment is purged with air in

preparation for entry or work, the air/vapour mixture in the equipment will reach its flammability range

at some stage of purging. At the same time, the pyrophoric iron sulphide would be exposed to the air

and react with the oxygen generating sufficient heat to become a source of ignition.

Dilute solution of Potassium permanganate is normally used as one of the oxidant for neutralization of

pyrophoric iron sulphide. It oxidizes pyrophoric iron sulphide and other sulphide compounds and is

potentially safe to use and easy to apply. At the discharge end, potassium permanganate's purple color

provides a positive visual indication when the pyrophoric iron sulphide has been neutralised.

Potassium permanganate reacts with the pyrophoric iron sulphide to form either iron oxides or iron

sulphate.

9FeS + 26KMn04 + 4H20 -----> 3Fe304 + 26Mn02 + 26K+ + 9SO4

2- + SOH

-

FeS + 2KMn04 -----> FeS04 + 2Mn02 + 2K+

Under normal conditions, KMnO4 should not be used with concentration above 2% in water (Its

solubility in water is 6.4 g/mL at 20ºC). Potassium permanganate is a strong oxidizer and should be

carefully handled when preparing the feed solution. The dark purple/ black crystalline KMnO4 solid can

cause serious eye injury, skin and inhalation irritant and fatal if swallowed in its concentrated form.

Handling Spent Sulphided Catalyst

In Hydro processing units, NiMo(Nickel Molybdenum) and CoMo(Cobalt - Molybdenum) based catalysts

are used for Hydro-treating and hydrocracking various petroleum fractions. These catalysts are inactive

when they are in their oxide forms. In order to activate it, sulphiding process is carried out, in which the

metal oxides are converted to their respective sulphides. Once the catalyst cycle is done or the activity

is reduced, it is replaced with fresh catalysts. The spent catalyst mostly, the metal sulphides are

pyrophoric and highly reactive when exposed to oxygen and this reaction generates heat, high enough

to ignite the carbon particles deposited over the catalysts.




Hence, these catalysts shall be unloaded & packed in inert atmosphere.

6.2 PRECAUTIONS AND SAFETY MEASURES

Following precautions shall be taken in carrying out work on equipment which are likely to have

pyrophoric deposits:

i. Process lines and other in-line equipment like vessel, columns, pumps, pump strainers, etc

shall be purged with inert gas or steam to remove hydrocarbon. Before opening up for air entry

/ man entry, chemical solution washing shall be used to diffuse pyrophoric iron, if any.

ii Pyrophoric scales and rust particles collected from the system shall be kept isolated from

oxygen by blanketing with inert gas or water until safe shifting and disposal.

For purging of combustible vapour and removal of pyrophoric deposits from storage tanks and towers,

following recommended practices shall be observed:

i The unit shall be purged with saturated steam to wet the interior surface.

ii A high capacity, flame proof air mover at the top manhole and a large fog nozzle in the neck of

the side manhole should be installed. The air mover should be bonded with the unit. The fog

nozzle should be turned on without delay and immediately thereafter, the air mover should be

turned on. Fog nozzle shall be continued without interruption until the tank is free of

hydrocarbons.

iii When the hydrocarbon content is reduced below the LEL then the fog nozzle should be isolated

and all loose scales shall be knocked down with high pressure water jet. The air mover should

be stopped after all the scales have been removed.

iv In order to avoid oxygen ingress & maintain inert atmosphere while removing spent catalysts

from Hydro processing reactors, continuous nitrogen supply shall be ensured once the reactor

is opened to atmosphere. All personnel on the job shall be equipped with robust breathing air

system. Only trained and medically certified persons shall carry out this job. Continuous

monitoring of oxygen, LEL and temperature in inert atmosphere of the vessel shall be in place.

6.3 Triethylaluminium (TEAL)

6.3.1 SOURCES AND HAZARDS OF TEAL

Triethylaluminum (TEAL) is widely used in petrochemical sector as a co-catalyst in the Ziegler-Natta

polymerization of olefins for manufacturing of high density and linear low density polyethylene,

polypropylene, synthetic rubber etc. When undiluted, TEAL is highly reactive, reacts explosively with

water and ignites spontaneously on contact with air (pyrophoric).




6.3.2 PRECAUTIONS AND SAFETY MEASURES:

Purified Nitrogen is preferred and should be used to pressure undiluted TEAL out of a shipping

container and into the suction of the TEAL feed/ charge Pumps. Nitrogen used in TEAL

systems for pressurizations, flushing, and as a blanketing material shall be ensured for levels

of oxygen and water continuously (O2 & moisture content should be < 0.1 ppm) with high level

alarms on the outlet of the Nitrogen source. Portable hoses should be avoided in unloading, if

used, fitness of connecting hoses shall be ensured.

Compatible solvents/liquids for example mineral oil etc (as recommended by Licensor) shall be

used for flushing/leak test of the TEAL system to produce a less reactive solution to achieve

non-pyrophoric concentrations and then shall be drained to a dedicated portable disposal tank

for disposal.

Fire hazards are the greatest concern in handling TEAL. The most effective fire extinguishing

agent is dry chemical powder applied from extinguishers pressured with inert gas. Other

suitable materials such as vermiculite, diatomaceous earth, or dry sand can be used. These

agents are effective because they absorb or blanket TEAL, thereby cutting off contact of the

TEAL with air. (MSDS of TEAL is attached as Annexure- I)

Direct water spray systems shall not be used to extinguish fire involving TEAL.

Shipping cylinders should be positioned within concrete fire barriers of at least two hours fire

resistance. Fire barriers shall be installed between TEAL cylinder / isotainer and other process

equipment (vessels, pumps, etc.). A catwalk should typically be built at the backside of the

concrete wall or mounted atop the firewalls at the back of the cylinders/isotainers to provide

access to the top of the cylinders / isotainers.

TEAL or its diluted solutions shall not be allowed to enter closed drains or sewers (either

process or storm channels), since there is always a potential that they may react violently with

water or other reactive chemicals contained in these sewers/channels.

Due to extremely hazardous nature of TEAL, a shutdown system shall be provided to isolate

and depressurize the portable shipping cylinders supplying TEAL to the process system. The

instrument air lines actuating the depressurizing valves should preferably be plastic or other

suitable material which will readily burn through under fire conditions, causing the automated

valves to go to their fail-safe positions.

Due to the hazardous nature of TEAL, the number of connections, vents, and drains should be

minimized. Process vents and drains handling TEAL shall be routed to vent pot where the

TEAL can form a non-pyrophoric mixture with mineral oil for further disposal.

Line sizes should be kept as minimum as possible in order to minimize the line volumes.

TEAL storage and handling facilities should be included in the Quantitative Risk Assessment

(QRA) study.




7.0 REFERENCES

I. Fire Protection Manual-for-Hydrocarbon Processing Plants-2nd Edition-Charles H. Vervalin 2. Fire and Safety Manual-Refineries and Petrochemicals Panel-National Safety Council 3. Hazards of Air - AMOCO 4. Safe Handling of Light Ends - AMOCO 5. Safe Furnace Firing - AMOCO 6. Thrope’s Dictionary of Applied Chemistry - Vol. X 7. API Guide for Inspection of Refinery Equipment Chapter V 8. Recommended Practice for Cleaning Petroleum Storage Tanks - API 2015. 9. Fire Protection in Refineries - API- RP - 2001, 1974. 10. Petroleum Refinery Engineering - Fourth Edition-W.L. Nelson. 11. Lange’s Handbook of Chemistry.




Annexure-I

TRIETHYLALUMINUM SAFETY DATA SHEET

According to Regulation (EC) No. 1907/2006 Version 6.0 Revision Date 31.03.2016

Print Date 06.03.2019 GENERIC EU MSDS - NO COUNTRY SPECIFIC DATA - NO OEL DATA

SECTION 1: Identification of the substance/mixture and of the

company/undertaking

1.1 Product identifiers Product name : Triethylaluminum Product Number : 257168

Brand : Aldrich

Index-No. : 013-004-00-2

REACH No. : A registration number is not available for this substance as the

substance

or its uses are exempted from registration, the annual

tonnage does not require a registration or the registration

is envisaged for a later registration deadline.

CAS-No. : 97-93-8

1.2 Relevant identified uses of the substance or mixture and uses advised against

Identified uses : Laboratory chemicals, Manufacture of substances

1.3 Details of the supplier of the safety data sheet

Company :

1.4 Emergency telephone number

SECTION 2: Hazards identification

2.1 Classification of the substance or mixture

Classification according to Regulation (EC) No 1272/2008

Pyrophoric liquids (Category 1), H250

Substances and mixtures, which in contact with water, emit flammable gases (Category 1), H260 Skin corrosion (Category 1B), H314

Serious eye damage (Category 1), H318

For the full text of the H-Statements mentioned in this Section, see Section 16.




2.2 Label elements

Labelling according Regulation (EC) No 1272/2008

Pictogram

Signal word Danger

Hazard statement(s)

H250 Catches fire spontaneously if exposed to air.

H260 In contact with water releases flammable gases which may ignite spontaneously.

H314 Causes severe skin burns and eye damage.

Precautionary statement(s)

P210 Keep away from heat, hot surfaces, sparks, open flames and other ignition sources. No smoking.

P231 + P232 Handle under inert gas. Protect from moisture.

P280 Wear protective gloves/ protective clothing/ eye protection/ face protection.

P305 + P351 + P338 + P310 IF IN EYES: Rinse cautiously with water for several minutes. Remove

contact lenses, if present and easy to do. Continue rinsing. Immediately

call a POISON CENTER/ doctor.

P370 + P378 In case of fire: Use dry powder or dry sand to extinguish.

P422 Store contents under inert gas.

Supplemental Hazard information (EU)

EUH014 Reacts violently with water.

2.3 Other hazards This substance/mixture contains no components considered to be either persistent,

bioaccumulative and toxic (PBT), or very persistent and very bioaccumulative (vPvB) at

levels of 0.1% or higher.

Reacts violently with water

SECTION 3: Composition/information 3.1 Substances Synonyms : Aluminumtriethanide

on ingredients




Formula : Molecular weight : CAS-No. :

C<SB>6</>H<SB>15</>Al 114.16 g/mol 97-93-8

EC-No. : 202-619-3

Index-No. : 013-004-00-2

Hazardous ingredients according to Regulation (EC) No 1272/2008 Component Classification Conc

entration Triethylaluminum

CAS-No. 97-93-8 EC-No. 202-619-3 Index-No. 013-004-00-2

Pyr. Liq. 1; Water-react. 1; Skin Corr. 1B; Eye Dam. 1; H250, H260, H314, H318

<= 100 %

For the full text of the H-Statements mentioned in this Section see Section 16.

SECTION 4: First aid measures

4.1 Description of first aid measures

General advice

Consult a physician. Show this safety data sheet to the doctor in attendance.

If inhaled If breathed in, move person into fresh air. If not breathing, give artificial respiration. Consult a physician.

In case of skin contact Take off contaminated clothing and shoes immediately. Wash off with soap and plenty of water. Consult a physician.

In case of eye contact Rinse thoroughly with plenty of water for at least 15 minutes and consult a physician.

If swallowed

Do NOT induce vomiting. Never give anything by mouth to an unconscious person. Rinse mouth with water. Consult a physician.

4.2 Most important symptoms and effects, both acute and delayed The most important known symptoms and effects are described in the labelling (see section 2.2) and/or in section 11

4.3 Indication of any immediate medical attention and special treatment needed

No data available

SECTION 5: Firefighting measures

5.1 Extinguishing media




Suitable extinguishing media

Dry powder

5.2 Special hazards arising from the substance or mixture

Carbon oxides, Aluminum oxide

5.3 Advice for firefighters

Wear self-contained breathing apparatus for firefighting if necessary.

5.4 Further information

No data available

SECTION 6: Accidental release measures

6.1 Personal precautions, protective equipment and emergency procedures

Use personal protective equipment. Avoid breathing vapours, mist or gas. Ensure adequate

ventilation.

Evacuate personnel to safe areas.

For personal protection see section 8.

6.2 Environmental precautions

Prevent further leakage or spillage if safe to do so. Do not let product enter drains.

6.3 Methods and materials for containment and cleaning up

Contain spillage, and then collect with an electrically protected vacuum cleaner or by wet-brushing

and place in container for disposal according to local regulations (see section 13). Do not flush with

water.

6.4 Reference to other sections

For disposal see section 13.




“OISD hereby expressly disclaims any liability or responsibility for loss or damage resulting

from the use of OISD Standards/Guidelines.”

SECTION 7: Handling and storage

7.1 Precautions for safe handling

Avoid inhalation of vapour or mist.

Keep away from sources of ignition - No smoking.

For precautions see section 2.2.

7.2 Conditions for safe storage, including any incompatibilities

Store in cool place. Keep container tightly closed in a dry and well-ventilated place. Containers which are

opened must be carefully resealed and kept upright to prevent leakage.

Never allow product to get in contact with water during storage.

Store at room temperature. Handle and store under inert gas. Air and moisture sensitive.

Storage class (TRGS 510): Pyrophoric and self-heating hazardous materials

7.3 Specific end use(s)

Apart from the uses mentioned in section 1.2 no other specific uses are stipulated

SECTION 8: Exposure controls/personal protection

8.1 Control parameters

8.2 Exposure controls

Appropriate engineering controls

Handle in accordance with good industrial hygiene and safety practice. Wash hands before breaks and

at the end of workday.

Personal protective equipment

Eye/face protection

Tightly fitting safety goggles. Faceshield (8-inch minimum). Use equipment for eye protection

tested and approved under appropriate government standards such as NIOSH (US) or EN

166(EU).

Skin protection

Handle with gloves. Gloves must be inspected prior to use. Use proper glove removal technique

(without touching glove's outer surface) to avoid skin contact with this product. Dispose of

contaminated gloves after use in accordance with applicable laws and good laboratory practices.

Wash and dry hands. Protective gloves against thermal risks

The selected protective gloves have to satisfy the specifications of EU Directive 89/686/EEC and

the standard EN 374 derived from it.

Body Protection

Complete suit protecting against chemicals, Flame retardant antistatic protective clothing., The

type of protective equipment must be selected according to the concentration and amount of the

dangerous substance at the specific workplace.

Respiratory protection

Where risk assessment shows air-purifying respirators are appropriate use (US) or type ABEK (EN






14387) respirator cartridges as a backup to enginee protection, use a full-face supplied air

respirator. Use respirators and components tested and approved under appropriate government

standards such as NIOSH (US) or CEN (EU).

Control of environmental exposure

Prevent further leakage or spillage if safe to do so. Do not let product enter drains.

SECTION 9: Physical and chemical properties

9.1 Information on basic physical and chemical properties

a) Appearance Form: liquid

b) Odour No data available

c) Odour Threshold No data available

d) pH Not applicable






e) Melting point/freezing point

f) Initial boiling point and boiling range






Melting point/range: -50 °C - lit.

128 - 130 °C at 67 hPa - lit.Flash point Not applicable

g) Evaporation rate No data available

h) Flammability (solid, gas) No data available

i) Upper/lower flammability or explosive limits No data available

j) Vapour pressure 3.8 mmHg at 80 °C

1 mmHg at 62.2 °C

k) Vapour density No data available

l) Relative density 0.835 g/cm3 at 25 °C

m) Water solubility Reacts violently with water.

n) Partition coefficient: n- octanol/water

Not applicable

o) Auto-ignition The substance or mixture is pyrophoric with the category 1.

Temperature

p) Decomposition temperature 120 °C –

r) Viscosity No data available

s) Explosive properties Not explosive

t) Oxidizing properties The substance or mixture is not classified as oxidizing.

9.2 Other safety information

No data available

SECTION 10: Stability and reactivity

10.1 Reactivity

Reacts violently with water.

10.2 Chemical stability

Stable under recommended storage conditions.

10.3 Possibility of hazardous reactions

Reacts violently with water.

10.4 Conditions to avoid

Exposure to moisture

10.5 Incompatible materials

Alcohols, Oxygen, Oxidizing agents, acids, Water, Organic halides, Bases






10.6 Hazardous decomposition products Hazardous decomposition products formed under fire conditions. - Carbon oxides, Aluminum oxide

Other decomposition products - No data available

In the event of fire: see section 5

SECTION 11: Toxicological information

11.1 Information on toxicological effects

Acute toxicity

No data availableTriethylaluminum

Skin corrosion/irritation

Causes skin burns.(Triethylaluminum)

Serious eye damage/eye irritation

Corrosive Risk of serious damage to eyes.(Triethylaluminum)

Respiratory or skin sensitisation No

data available(Triethylaluminum)

Germ cell mutagenicity

No data available(Triethylaluminum)

Carcinogenicity

IARC: No component of this product present at levels greater than or equal to 0.1% is identified as

probable, possible or confirmed human carcinogen by IARC.

Reproductive toxicity


Specific target organ toxicity - single exposure


Specific target organ toxicity - repeated exposure

No data available

Aspiration hazard


Additional Information

RTECS: BD2050000

Material is extremely destructive to tissue of the mucous membranes and upper respiratory tract, eyes, and

skin., Cough, Shortness of breath, Headache, Nausea(Triethylaluminum)

SECTION 12: Ecological information

12.1 Toxicity

No data available

12.2 Persistence and degradability

No data available






12.3 Bioaccumulative potential

No data available

12.4 Mobility in soil


12.5 Results of PBT and vPvB assessment

This substance/mixture contains no components considered to be either persistent, bioaccumulative and

toxic (PBT), or very persistent and very bioaccumulative (vPvB) at levels of 0.1% or higher.

12.6 Other adverse effects

No data available

SECTION 13: Disposal considerations

13.1 Waste treatment methods

Product

Burn in a chemical incinerator equipped with an afterburner and scrubber b highly flammable. Offer

surplus and non-recyclable solutions to a licensed disposal company.

Contaminated packaging

Dispose of as unused product.

IATA: 3394

ADR/RID: ORGANOMETALLIC SUBSTANCE, LIQUID, PYROPHORIC, WATER-REACTIVE

(Triethylaluminum)

IMDG: ORGANOMETALLIC SUBSTANCE, LIQUID, PYROPHORIC, WATER-REACTIVE

(Triethylaluminum)

IATA: Organometallic substance, liquid, pyrophoric, water-reactive

(Triethylaluminum) Passenger Aircraft: Not permitted for transport

Cargo Aircraft: Not permitted for transport

14.3 Transport hazard class(es)

14.6 Special precautions for user

ADR/RID: 4.2 (4.3) IMDG: 4.2 (4.3) IATA: 4.2 (4.3)

14.4 Packaging group

ADR/RID: I

IMDG: I

IATA: -

14.5 Environmental hazards

ADR/RID: no

IMDG Marine pollutant: no

IATA: no

SECTION 14: Transport information

14.1 UN number

14.2

ADR/RID: 3394

UN proper shipping name

IMDG: 3394






No data available

SECTION 15: Regulatory information

15.1 Safety, health and environmental regulations/legislation specific for the substance or mixture

This safety datasheet complies with the requirements of Regulation (EC) No. 1907/2006.

15.2 Chemical safety assessment

For this product a chemical safety assessment was not carried out

SECTION 16: Other information

Full text of H-Statements referred to under sections 2 and 3.

EUH014 Reacts violently with water.

H250 Catches fire spontaneously if exposed to air.

H260 In contact with water releases flammable gases which may ignite spontaneously.

H314 Causes severe skin burns and eye damage.

H318 Causes serious eye damage.

oil industry safety directorate - oisd.gov.in

Documents