Template No. 5-0000-0001-T2 Rev. 1 Copyrights EIL All rights reserved 1 RAPID RISK ASSESSMENT OF RAMAGUNDAM FERTILIZER COMPLEX Doc No.: A512-04-41-RRA-0001 Rev. No: A RAPID RISK ASSESSMENT PROJECT : RAMAGUNDAM FERTILIZER COMPLEX OWNER : CONSORTIUM OF EIL, NFL AND FCI CONSULTANT : ENGINEERS INDIA LTD. A 11.11.14 ISSUED AS DRAFT NC DK GG Rev. No Date Purpose Prepared by Reviewed by Approved by
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For risk Assessment the representative average annual weather conditions are assessed based on
the following:
Wind speed less than 2 m/s would be experienced for 38-42% of the time in a year. In order to
realize the worst hazardous distances, weather stability of “F” was selected with wind speed 1
m/s for consequence analysis. Wind speed of 2-5 m/s can be realized for the remaining part of
the year. Cloud cover for these months is in the ranges of 2.2 to 6.5 oktas. This results in
stability class of D foe wind speeds of 2-5 m/s. As a conservative approach minimum velocity, 2
m/s has been selected with stability class D for risk Assessment. Average wind speed of greater
than 4 m/s can be realized in the month of June. Cloud cover for this month is 3.8. From this
information stability class of “D” was selected with wind speed 5 m/s for risk assessment.
Discussions, conclusions and recommendations pertaining to consequence analysis are based on
the worst weather condition. The consequence results are reported in tabular form for all the
weather conditions and are represented graphically for worst weather condition.
In the present study, the entire range of representative wind speeds, both during the day and
night, and cloud amount have been considered.
Table 2.5.3: Weather Conditions
Wind Speed Pasquill Stability
1 F
2 D
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3. PROCESS DESCRIPTION
3.1 AMMONIA UNIT- KBR
The key process features of KBR Ammonia purifier process are feed gas flexibility, mild
primary reforming, secondary reforming with excess air, mild reformed gas boiler conditions, a
gas turbine driven high efficiency process air compressor, cryogenic removal of excess nitrogen
and inerts from syngas, efficient synthesis scheme with a single horizontal converter and unitized
chiller. Purifier process also produces required CO2 by-product flow to convert the entire 2200
MTPD NH3 product to urea. The purifier process is inherently low energy consuming process
due to its unique parameters and integration as below. All of the process features in this plant
have been in operation in numerous KBR Purifier plants. Each of these features is discussed in
the following paragraphs.
Feed Gas Flexibility:
The KBR Purifier process uses a cryogenic nitrogen wash step to remove impurities from the
makeup synthesis gas. The process is uniquely able to handle variations in the composition of the
natural gas feed, including variations in hydrocarbon contents, N2 content and CO2 content. The
Purifier has the ability to absorb the variations in the raw synthesis, and maintain a stable
composition of the makeup gas to the synthesis loop.
Conversely, in a conventional plant, the flow rate of process air to the secondary reformer needs
to be controlled carefully to obtain the required H2 to N2 ratio in the makeup gas to the synthesis
loop.
With the ability to vary the flow rate of the process air, the loads on the air compressor,
secondary reformer and cryogenic Purifier were adjusted to maintain high ammonia capacity.
Unlike in the conventional process, the primary reformer’s operation has little impact during feed
gas composition variation. Operationally the whole plant is adjusted easily with varying feed gas
composition just by adjusting process air flow. Therefore, the plant has been able to maintain
high capacity during variations in the feed gas composition and is proven operationally flexible
due to this unique process.
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Mild Primary Reforming:
Primary reforming is carried out at a much lower temperature than in conventional ammonia
process. The methane content of the process gas going to the secondary reformer is much higher
than in conventional ammonia plant. More of the reforming is shifted to the secondary reformer,
which is more suitable to the temperatures involved and in which essentially 100 percent of the
heat is recovered. The radiant duty in the primary reformer is thus greatly reduced.
Integrated Reforming Furnace & Gas Turbine:
Radiant duty of the primary reformer furnace in the Purifier Process is only about 60% whereas
power requirement of the process air compressor is about 1.5 times more of that in a
conventional ammonia plant. Due to this unique combination, the oxygen content of the gas
turbine exhaust provides a good match with the requirement of combustion air to the primary
reformer furnace burners. The exhaust of the gas turbine driver of the process air compressor is
thus integrated with the primary reformer furnace.
The gas turbine driven air compressor is started-up standalone without requiring imported steam
thus required capacity of the OSBL package boiler is significantly less. Not only installed cost is
reduced this way but energy efficiency of the ammonia plant as well as the whole complex is
significantly increased with such integration as commercially proven in numerous Purifier plants.
Ammonia plat exports steam to urea plant/ CO2 compressor steam turbine and offsite users and
meets all their demand by aforementioned integration as well as due to the fact that process
steam consumption in Purifier process reforming is less due to lower S/C ratio enabled due to
higher allowable CH4 slip exit the secondary reformer.
Ramagundam Power & Steam Integration with the Urea/OSBL:
The power & steam of Ramagundam complex is integrated with the Captive Power Plant (CPP)
to maximize overall energy efficiency. Purifier process due to its integrated furnace-gas turbine
feature and lower ISBL steam consumption along with the gas turbine based CPP are able to
meet the entire steam and power demand of the whole complex including CO2 compressor steam
turbine urea process and offsite. The configuration of CPP plant will have a gas turbine driven
generator (GTG) and steam turbine driven generator (STG). Heat recovery from the GT exhaust
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is maximized and steam is generated at different pressure levels. Ramagundam will require MP
steam from OSBL only during it start-up & emergency, however start up steam is less, only
about 90t/h as air compressor does not require steam for its start up. Unlike in conventional
plants, Purifier plant does not require huge MP steam during trip of secondary reformer which is
a big relief while managing the transient operations.
Secondary Reforming with Excess Air:
In a conventional secondary reformer, the quantity of air is limited to the amount that is required
to produce a 3-to-1 ratio of H2 to N2 in the synthesis gas. With the Purifier process, the H2/N2
ratio is controlled at the Purifier so that extra air can be used in the secondary reformer. The
extra air provides additional reaction heat. Nearly 100 percent of the heat released in this vessel
is recovered compared to 40 to 50 percent in the radiant zone of the primary reformer. Therefore
shift of the duty from primary to secondary reformer makes the process more efficient.
In addition, because of the downstream Purifier, the allowable methane leakage is much higher
than in conventional plants, which further relaxes the reforming load by lowering the secondary
reformer outlet temperature. These two features result in much milder reforming conditions that
are advantageous in terms of both steady and reliable operations and longer equipment life.
The extra un-reformed methane, together with surplus N2 and most of the argon are recovered in
the Purifier system later in the process sequence, and returned to the reformer furnace as fuel.
Mild Reformed Gas Boiler Conditions:
Reformed gas (RG) boiler in Purifier process operates under significantly mild conditions of
inert gas temperature as well as heat flux. Typically RG boilers exit the secondary reformer may
be prone to failure due to severe high inlet temperature and high heat flux. Purifier process
enables to operate it at more than 100OC cooler which minimizes the process severity and thus
enhances equipment reliability.
More CO2 production for Urea Plant:
Since Purifier Process uses excess process air in the secondary reformer, more CO2 is produced
in the reforming section compared to a conventional process. Consequently, all the required CO2
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for conversion of 2200 MTPD ammonia to urea, is produced from the CO2 removal unit as by-
product, even with light feed natural gas composition as in Ramagundam. In a conventional
ammonia plant, the CO2 production will always be shorter then required by urea plant which will
need to be made up by either having a large surplus syngas or by recovering Co2 from the
furnace flue gas which is not required in case of Purifier process.
Optimally Integrated 2-stage OASE Process based CO2 removal:
A 2-stage OASE process based CO2 removal system, licensed from BASF, has been optimally
integrated into the Purifier process based ammonia flow sheet. As explained later, KBR’s
Purifier Ammonia Process allows using lower steam/carbon ratio in the reformer mixed feed and
as a consequence the higher methane slip from the secondary reformer can be removed by the
cryogenic unit. The Reboiler heat duty available in the purifier process is well matched with low
Reboiler duty required for solvent regeneration in a 2-stage OASE process. KBR was first in the
ammonia industry to incorporate a 2-stage OASE (former aMDEA) process (a 1980’s Purifier
process based plant) and has a leading position ever since for integration and execution of this
CO2 removal technology.
Cryogenic Purification Unit:
The cryogenic purification unit is the heart of the KBR Purifier Process. In this unit, essentially
all the methane and about 60 percent of the argon in the raw synthesis gas are removed together
with the excess nitrogen as waste gas. This waste gas is returned to the primary reformer furnace
as fuel after it has been used to regenerate the driers. The product from this unit is a highly pure
synthesis gas. The synthesis gas contains H2 and N1 in ratio of 3 without any water or carbon
oxides, which are poisons for the synthesis catalyst, and inert content is about 0.2 percent.
Most of the net cooling required by the Purifier is provided by a gas expander, which causes a
modest pressure drop in the synthesis gas stream. Further cooling is provided by low-pressure
vaporization of the waste gas described above. The Purifier has two controls. The energy balance
is controlled by the amount of work removed from the system by the expander. The material
balance is controlled by a valve in the line on the liquid from the bottom of the column. This
valve is controlled by a hydrogen analyzer on the purified process gas exit the cryogenic system.
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The highly pure and dry synthesis gas produced in the Purifier permits the operation of the
synthesis loop at lower pressure for the same level of refrigeration, thereby saving syngas
compressor power. This also leads to a very efficient ammonia synthesis process scheme with
savings in both syngas and refrigeration compressor power.
The cryogenic step allows a higher concentration of methane in the raw synthesis gas leaving the
secondary reformer since methane is removed from the syngas in the Purifier and used as fuel.
Thus, the secondary reformer outlet temperature is typically lower by more than 100°C than in a
conventional plant, and primary reformer radiant heat input as well as outlet gas temperature is
significantly less. Also, since higher methane content is allowed exit the secondary reformer, a
lower steam/carbon ratio in the primary reformer mixed feed (than in conventional process) can
be used. The lower S/C ratio maximizes MP steam export to the OSBL which makes the plant
more efficient. Complete removal of all traces of water and carbon dioxide lengthens the life of
the synthesis catalyst.
Another key advantage of the Purifier is that it stabilizes the operation of the plant by ' separating
the front end of the plant from the back end. First, it permits setting the hydrogen-to-nitrogen
ratio in the synthesis loop independently of the secondary reformer operation. Second, it
effectively compensates for any problems or upsets in the front end. For example, during
instances when the CO or the C02 leakage is higher than design, the CO and CO; will be
converted to methane in the methanator and all methane will be removed in the Purifier. The
synthesis loop operation will not be affected.
In a conventional ammonia process the above flexibility is not available. For example, the
process air rate must be carefully controlled in the front end of the plant to maintain a three- to-
one hydrogen-to-nitrogen ratio in the makeup gas to the synthesis loop. Also, during instances of
higher than normal CO or CO; leakages, the synthesis loop purge rate would have to be
increased to maintain the design loop inert level.
Finally, the Purifier also acts as a purge gas recovery unit as the entire loop purge is recycled to
this unit for hydrogen recovery as required. Purge gas from other existing ammonia units within
the complex can also be processed in this unit for increased ammonia production with minimal
added investment.
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During plant start-up, the Purifier can be cooled down during the same time period when the
synthesis converter is heated up. Operators of Purifier plants report that the Purifier does not
extend the total start-up time of the plant. During a short shutdown, the inventory of liquid
nitrogen in the Purifier will keep the system cold, allowing quick restart. If preferred any time,
ammonia plant can be operated in Purifier bypass mode.
High Production Rates through Extended End of Run & Turnaround Flexibility:
Unlike in conventional ammonia plants, purifier plant can maintain production rates with rising
methane slip from reformers or rising CO slip from shift converter as consequent rising inerts
(methane) in make-up gas are removed in the purifier cold box. This is possible only in Purifier
process where all the make-up gas to synloop is processed through the cold box. Production rates
are thus maintained through extended operations of catalysts to end of runs which benefits the
owner greatly on plant life cycle basis. It provides much needed flexibility in planning plant
turnaround. Such details are compared in an attached published paper
Efficient KBR synthesis Scheme:
Since the makeup gas from the Purifier contains no carbon oxides and water, which are poisons
to the synthesis catalyst, it can be directly fed to the converter, joining with the recycle gas. Also,
the make-up syngas has little inert with negligible CH4 which provides a low inert synthesis loop
with high partial pressure of reactants H2 and N2. This process scheme has two advantages.
First, refrigeration requirements will be lower than other schemes, in which the moisture
containing makeup gas is mixed with converter effluent to first pass through the chilling train
before going back to the converter.
Second, the ammonia converter capacity is increased because of lower ammonia content in the
feed as a result of mixing the ammonia free makeup gas with the recycle gas. The low inert level
in the makeup gas also permits operation of the synthesis loop at lower pressures for a given
level of refrigeration, saving syngas compressor power.
Due to very low inert contents in a syn-loop based on purifier process, loop pressure is
significantly lower and required conversion is achieved in a single converter using lesser
catalyst. Thus, efficient ammonia plant with lesser compression power is achieved with
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significantly less CAPEX. Attached published paper compares impact of make-up gas quality on
various types of syn-loops.
In the KBR synthesis scheme, ammonia synthesis is carried out in a single horizontal, three bed
converter.
Refrigeration in the synloop uses unitized chiller. This exchanger takes the place of several
refrigeration chillers and a recycle exchanger, thereby eliminating expensive high-pressure
piping and fittings and significantly reducing the pressure drop compared to the sum of
individual chiller pressure drops. The basic concept of this unit is the use of concentric tubes and
a compartmentalized shell to replace several equipment items with one. The converter effluent
flows through the annuli of the concentric tubes, with the recycle gas flowing through the inner
tubes. Refrigeration ammonia at four different temperatures and pressures boils on the shell side
in four compartments. Thus the converter effluent is simultaneously cooled by two media, the
recycle gas and ammonia refrigeration.
Due to highly pure synthesis loop makeup gas feed from the purifier, the life of the ammonia
synthesis catalyst is estimated as 18 years compared to only 10 years typical for that in the
conventional synthesis loop. Significantly higher catalyst life is typically found in purifier plants
in industry.
The synloop also incorporates high-pressure steam generation which improves overall heat
integration and improves energy efficiency by exporting steam for OSBL usage.
3.2 UREA UNIT- STAMICARBON
The Ammonia and CO2 from ammonia unit caters to Stamicarbon’s Urea melt of 3850 MTPD
which is based on the Pool Condenser Concept. Ammonia and carbon dioxide are introduced to
the high pressure synthesis using a high-pressure ammonia pump and a carbon dioxide
compressor. The ammonia then drives an ejector, which conveys a carbamate solution into the
pool condenser. In the high-pressure stripper, the carbon dioxide, entering the synthesis as a feed,
flows counter-current to the urea solution leaving the reactor. On the shell side, the high-pressure
stripper is heated with steam. The off-gas of the high-pressure stripper, containing the carbon
dioxide, together with the dissociated carbamate, is then fed into the pool condenser. In the pool
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condenser, ammonia and carbon dioxide are condensed to form carbamate, and a substantial part
of the conversion to urea is already established here. The heat released by condensation and
subsequent formation of carbamate is used to produce re-usable low-pressure steam.
After the pool condenser, the remaining gases and a urea carbamate liquid enter the vertical
reactor. Here, the final part of the urea conversion takes place. The urea solution then leaves the
top of the reactor (via an overflow funnel) before being introduced into the high-pressure
stripper. Ammonia and carbon dioxide conversions in the synthesis section of a Stamicarbon
carbon dioxide stripping plant are high, reducing the need for a medium pressure stage to recycle
any unconverted ammonia and carbon dioxide. As a result, the Stamicarbon CO2 stripping
process is the only commercial available process that does not require a medium-pressure
recirculation stage downstream from the high-pressure stripper. Gases leaving the reactor are fed
into the high-pressure scrubber. Here, the gases are washed with the carbamate solution from the
low-pressure recirculation stage. The enriched carbamate solution is then fed into the high-
pressure ejector and, subsequently, to the pool condenser. Inert gases, containing some ammonia
and carbon dioxide, are then released into the 4-bar absorber.
Low-pressure recirculation section
This stage recovers the ammonia and carbon dioxide still present in the urea solution coming
from the high-pressure stripper. Thanks to the low ammonia and carbon dioxide concentrations
in the stripped urea solutions, the Stamicarbon CO2 stripping process is the only process that
requires just one single low-pressure recirculation stage. Coming out of the stripper, the urea
solution is fed into the dissociation heater, where most of the ammonia and carbon dioxide are
removed. The heat required for this heater is derived from the condensation of the low-pressure
steam produced in the urea synthesis. The ammonia and carbon dioxide are then fed into the low-
pressure carbamate condenser, where they are condensed. Because the ratio between ammonia
and carbon dioxide in the recovered gases is optimal, the quantity of water needed to dilute the
resultant ammonium carbamate solution can be kept to a minimum, maximizing conversion
figures for the urea plant. The resultant carbamate solution is fed, via a high-pressure carbamate
pump, back to the synthesis as a scrubbing agent in the high-pressure scrubber.
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Before entering the urea solution tank, part of the water present in the urea solution is evaporated
by further preflashing in two steps (atmospheric and sub-atmospheric). The vent gas from the
recirculation stage is practically free from ammonia because it is scrubbed in an atmospheric
absorber.
Evaporation section
Waste-water treatment section before the entire urea production process is complete; the urea
solution present in the urea solution tank must be concentrated. The urea solution is therefore
sent to an evaporation section. The topology of this evaporation section depends on the applied
finishing section (prilling, granulation or pastillation). Depending on the requirements of the
finishing section, the evaporation section may, for example, consist of two consecutive
evaporators, where the water in the urea solution is evaporated under vacuum conditions. The
remaining urea melt has a urea concentration varying from 96 to 99.7wt%, depending on the
requirements of the downstream finishing section.
Waste-water treatment section
The process condensate coming from the evaporation section, together with other process
effluents such as sealing water from stuffing boxes, contains ammonia and urea. All of the
process condensate is collected in the ammonia water tank. From this tank, the water is fed to the
top part of the desorber. In the top part of the desorber, the bulk of ammonia and carbon dioxide
are stripped off from the water phase by using the off-gas from the bottom part of the desorber as
a stripping agent. The descending effluent still contains urea and some ammonia. To remove this
urea, this effluent is then fed to the hydrolyzer. The hydrolyzer is a liquid-filled column. In the
hydrolyser, the urea, at elevated pressure and temperature, is dissociated into ammonia and
carbon dioxide by the application of heat (steam) and retention time. The process condensate
feed is kept in counter-current contact with the steam in order to obtain extremely low urea
content in the hydrolyzer effluent. The remaining ammonia and carbon dioxide in the effluent of
the hydrolyzer are stripped off with steam at a reduced pressure in the bottom part of the
desorber. The off-gases leaving the top part of the Desorber are recycled to the synthesis section
after being condensed in the reflux condenser. The purity of the remaining water satisfies
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requirements for boiler feed water make-up or cooling water make-up - which means that
Stamicarbon urea plants do not produce a waste-water stream.
This is followed by the adiabatic expansion and MP section and prilling section. Steam and
condensate system ensure that overall energy consumption is optimized.
3.3 Offsites
Two ammonia storage tanks of storage capacity 15000 m3 and 5000 m3 along with the tank
manifold are envisaged in the north side of the complex. Waste water generated in the ammonia
and urea plants will be treated in the new ETP
3.4 CPP
New CPP of 29.1 MW (normal)/ 34.6 MW (max) (GTG + HRSG) will be installed.
4. HAZARDS ASSOCIATED WITH THE PROJECT
The new manufacturing facility handles various hazardous materials like Natural gas, Ammonia,
Carbon monoxide, carbon dioxide and various other hydrocarbons which have a potential to
cause fire, explosion and release/leakage of toxic chemicals may lead to major hazards.
There are various modes in which flammable and toxic chemicals can leak into atmosphere
causing adverse affects. It may be a small leak from gaskets of the flanged joints, failure of the
pipeline or even catastrophic failure of storage tanks.
4.1 CATEGORIES OF RISKS ASSOCIATED WITH THE COMPLEX
The manufacture of anhydrous liquid ammonia involves processing of hydrocarbons under high
temperature, high pressure conditions in the presence of various catalysts, chemicals etc. Typical
risks are as follows:
a) Ammonia Plant:
Fire / Explosion Risks
Glands/seal leaks in valves, pumps, compressors handling hydrogen, natural gas,
naphtha, synthesis gas etc. Hose/pipe failure, leakage from flanged joints carrying combustible gases, vapours,
liquids.
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High / Low Temperature Exposure Risks
Burns due to contact with hot surfaces of pipelines, equipments, etc. or leaking
steam lines, process fluids at high temperature. Frost bite due to contact with anhydrous liquid ammonia at -33 deg. C Burns due to contact with pyrophoric catalyst
Toxic Chemicals Exposure Risks
Asphyxia due to inhalation of simple asphyxiants like CO2 , N2, H2, CH4, naphtha
etc. and chemical asphyxiants like CO, NH3, Nickel carbonyl, V2O5, Hydrazine, NOx, SOx, H2S etc.
Acute toxicity due to inhalation of catalyst dusts containing heavy metals like Ni, Cr, CO, Mo, Fe, Zn, Alumina etc. and silica gel molecular sieves, insulation fibers/dusts.
Corrosive / Radioactive Chemicals Exposure Risks
Severe burns, damage to eyes, skin and body tissues due to contact with anhydrous
ammonia
b) Urea Plant
The manufacture of urea involves reaction of Ammonia and Carbon dioxide under high temperature & pressure and subsequent recovery and concentration of the solution at various pressure stages. Typical risks are as follows: Fire / Explosion Risks
Ammonia leaks from glands/ pump seals or flanged joints piping resulting in formation explosive mixtures in air. Accumulation of H2 may take place in HP Section in case CO2 purity from
Ammonia Plant is not within allowable limits. Ignition of this accumulated H2 can occur due to dissipation of static charge.
High / Low Temperature Exposure Risks
Refer to risks in Ammonia Plant
Toxic Chemicals Exposure Risks
Asphyxia due to inhalation of simple Exposure risk asphyxiants like CO2, N2, chemical asphyxiant and ammonia. Solution of Urea, Ammonium carbamate and ammonium carbonate containing high NH3 content.
Irritation due to inhalation of urea dust. Corrosive / Radioactive Chemicals Exposure Risks
Severe burns, damage to eyes, skin and body tissues due to contact with anhydrous ammonia, conc. Urea and Ammonium carbamate solutions.
c) Power Plant
The captive Power Plant involves generation of steam in N.G./Naphtha-fired boilers and utilizing
the steam in Urea and Ammonia plants. Typical risks are as follows:
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Fire / Explosion Risks
Explosion and fire risks associated with storage and handling of B Class (Naphtha) and Natural gas handling pipelines (Refer off site Facilities).
Fire Box explosion in Boiler High / Low Temp. Exposure Risks
Burns due to contact with hot surfaces of pipelines, equipments, etc. or leaking steam lines
Toxic Chemical Exposure Risk
Asphyxia due to inhalation of SOX and NOx. Irritation due to inflammation caused by inhalation of Natural gas and the
Naphtha vapors
d) Offsite Facilities
The offsite facilities consist of integrated units for water and effluent treatment, inert gas
generation, cooling towers, storage of ammonia, supply / distribution of utilities like compressed
air, water, etc. Potential risks in the above offsite facilities are essentially on account of handling
of corrosive, toxic and reactive chemicals as well as inflammable petroleum products.
Fire / Explosion Risks
Gland / Seal leaks in valves, pumps, compressor, handling naphtha, N.G., ammonia hydrogen, syngas etc.
Hose / pipe failure, leakage from flanged joints in pipes conveying petroleum products, ammonia, hydrogen, syngas, etc.
Leakage of petroleum products during tanker unloading operations Overheating / pressurization of storage tanks Improper earthing/ lightning protection of storage tanks and pipelines Improper sealing of floating roof tanks In adequate / improper breather valves leading to tank failures.
High / Low Temp. Exposure Risks
Burns due to contact with hot surfaces of pipe lines, equipments, etc or leaking steam lines.
Heat radiation burns from high intensity flames from the flare stack. Frost bite due to contact with anhydrous liquid ammonia at – 33 °C
Toxic Chemicals Exposure Risks
Asphyxia due to inhalation of simple asphyxiants like N2, H2, Naphtha, etc. and Chemical asphyxiants like Cl2, NH3, NOx, Sox, etc.
Toxicity due to inhalation of catalyst dust containing heavy metals like Ni, Pd, Alumina etc. and perlite / insulation fibers, silica gel dust
Corrosive Chemicals Exposure Risks
Severe burners, damage to eyes, skin & body tissues due to contact with corrosive chemicals like anhydrous liquid Ammonia, Sulphuric acid, Hydrochloric acid, etc.
NOTE: All the above categories have been listed for representative purpose only. Risk
study will not be carried out for all the cases
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4.2 HAZARDS ASSOCIATED WITH MATERIALS HANDLED
AMMONIA:
It is a colorless gas with a sharp, strong odor similar to “smelling salts” which is readily
detectable at 20 ppm and is highly toxic gas, its IDLH being 300 ppm. It is also a combustible
gas which can explode under certain circumstances, although its lower explosive limit is rather
high being of the order of 16%. Anhydrous Ammonia is an irritating, flammable, and colorless
liquefied compressed gas packaged in cylinders under its own vapor pressure of 114 psig at 70oF.
Ammonia can cause severe eye, skin and respiratory tract burns and is severely irritating to nose,
throat, and lungs. Vapor contact may cause irritation and burns. Contact with liquid may cause
freezing of the tissue accompanied by corrosive caustic action and dehydration. Ammonia
Overexposure may also cause central nervous system effects including unconsciousness and
convulsions.
CARBON MONOXIDE:
Carbon monoxide is a poisonous, flammable and odorless high-pressure gas which acts on blood,
causing damage to central nervous system (CNS) and could be fatal even with adequate oxygen.
It can form explosive mixtures with air at 12.5-74% concentration. Self-contained breathing
apparatus must be worn by rescue workers. Depending on the concentration and duration of
exposure, inhalation may cause headache, drowsiness, dizziness, excitation, rapid breathing,