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Amuay UCVE Event Aug 25 2012 (Saturday)around 1:10 AMDisclaimer:
RMG has developed the following material based on detailed analysis
of information freely available on the net, our data bases, and
from our industry contacts. We believe that an accurate event
simulation and fact sheet has been developed, describing to the
best of our knowledge the facts and consequences without warranties
or judgments of any kind
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In Amuay olefins are produced inthe cat cracking and in the
coking operations
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Olefins are used to produce alkylate, amotor gasoline
componentfor octane improvement
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Olefins are stored in spherical tanks due to itshigh vapor
pressure and low boiling point
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If this compound is released to the atmosphere, a vapor cloud
will form This cloud mass will be about 50% heavier than air
Once released, it will flow in the ground like a river of
fog
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Insiders reported that a olefins pump was leakinga pump seal
failure perhaps?
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In Amuay the strong prevailing trade winds blow there most of
the year
These are a key design and operational factorWindOlefins pump
leak not fixed, last for days
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Randomly, during August and September, and before a
downpourprevalent winds may slow, sometimes change direction, from
its regular eastwarddirectionWindOlefins pump leak not fixed, last
for days
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In the preceding days, atmospheric conditions caused showers in
the area, the wind to erratically slow and change direction
WindOlefins pump leak not fixed, last for days
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Olefins pump leak not fixed, last for daysAn operational
decision seems to have been madeto maintain the equipment
inoperation and keep the production on, relying on the wind to
disperse the leaked vapors.
Those, in concentrations below 2% in weightrelative to air
(LEL), are not flammableClick to continue
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The day before leaking vapor had reached the facility
perimeter
Amounts exceeding the allowable LEL (explosivity) were detected
in the environment
On Friday, a neighboring lube oil manufacturing plant had to be
evacuated due to poor air qualityWindLeak source
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Weather situation seems to improve later on the day.
A team of workers at the Lube oil manufacturing plant return,
and tries to catch up with production on Friday late nightWindLeak
source
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About Friday midnightThe wind slows. The now stillness does
nothingto disperse the olefin vapors, which nowbegin to
accumulate
In a tragic coincidence of events, the leak suddenly becomesmuch
largerWindLeak source
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Leak sourceWind
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Leak sourceLow points/ pathLow points/ pathWind
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Leak sourceWindLow points/ pathLow points/ path
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Leak sourceWind
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Leak sourceWind
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Leak sourceWind
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Leak sourceWind
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Leak sourceWind
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Leak sourceOne worker is on the pedestrian overpass, walks away,
leaving the areaNational Guards livehere with their
familiesWind
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Leak sourceOne worker is on the pedestrian overpass, walks away,
leaving the areaOne vehicle southbound approaches the vapor
cloudLube oil plant team is still at workWind
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Leak sourceOne worker is on the pedestrian overpass, walks away,
leaving the areaOne vehicle southbound approaches the vapor
cloudLube oil plant team is still at workWind
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Leak source, now ignited, can be seen in the next photographsThe
worker on the pedestrian overpass diesLikely the car ignites the
cloud here. The explosion force pushes it towards the opposite curb
as seen in the attached picFive lube oil plant workers perish while
still at workMany people, houses are affected by the strong
shockMany people, houses are affected by the strong shockWind
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Olefins pump site
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Olefins pump site
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Overpass damage pic 2House damage pic 1Lube oil plant damages
pic 5WindBusiness damage pic 3Lube oil plant damages pic 6Business
damage pic 4
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2
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3
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4
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5
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6
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The operational decisionto maintain the equipment inoperation
and depend on the wind to to disperse the leaked vapors was a
tragically poor one
Fifty one lives lost so far and many more badly burned
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"I am living miracle.. it was not my time", said Edino Rafael
Muoz Lambertino (35), a man of Libertad de Barinas, survivor of the
blast, who was held imprisoned that night in the 44 National Guard
depot located next to the Amuay Refinery. After being arrested on
allegedly soliciting charges, he was to be released next day. Why
were you not sleeping then?... He was talking with the national
guards. "We were then telling tales and the next day they were
dead". He said that about 1 am on Saturday, they began to leave the
facility since the smoke was thick. "Let's go there, need to make
several rounds, the guards told us." Edino was led to the first
jeep with 7 guards. The jeep stutter half way, and when they tried
restarting the vehicle, there was an explosion. "It seems that it
had lifted". "My mind was blank, like a dream, a nightmare". Edino
jump the car and ran down the street until a corner where stop to
rest. When I look over there it came as a wave of fire, I laid down
and prayed." "It went over and then returned again." After that
flash, Edino looked back at the jeep: it was burning with all its
passengers as well as another vehicle with military guards and a
lady with a 5-month-old girl. "All died. I saw them the next day in
the newspaper. It is strange that they stay put and did not run
away." Scared, Edino resumed his escape and met a family who were
evacuating. "Lord, help me that I can barely walk", yelled Edino to
them, who then took him to the hospital. "I had glass fragments in
my skin.
On Saturday night, Edino had asked the guards why the strong
smell of gas. "The guards said that these are valves that open at
times and that it was normal." "That's to regulate the tanks". But
the atypical event of that day was that the gas began spreading
across the street "as fog", according to himLink:
http://www.ultimasnoticias.com.ve/Noticias/Actualidad/Sucesos/Testimonio-en-Amuay---Estoy-vivo-de-milagro--no-me.aspx
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Unconfined Vapor Cloud Explosion
UVCE
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The results seen in the prior pictures suggest a gas phase
explosion event, which generated a large overpressure without the
presence of confining walls.
This is referred to as Unconfined Vapor Cloud Explosion
(UVCE).
When a flame travels through the unconfined gas cloud with high
velocity, the gas/air mixture ahead of the flame is unable to move
away quickly enough to allow free expansion of the combustion
products formed by the flame. As a result pressure wave is formed
ahead of the flame front with the destructive forces seen. Edino
was a lucky witness to this.
The presence of obstacles (called congestion, observed where
buildings may be in the path) within the flow field of the gas
cloud produces turbulence which enhances the burning velocity,
accelerates the production of combustion products and increases the
flame speed. The higher the velocity of the flame, the higher the
pressure generated ahead of it. If very high flame speeds are
produced, a Transition from Deflagration to Detonation (DDT) can
occur.
A detonation involves a very high pressure shock wave that
further auto-ignites the gas/air mixture. The combustion of this
mixture then provides the energy to sustain the shock wave, which
may extend further than the vapor cloud. As a result, a detonation
is self-sustaining as long as the concentration of gas is within
certain limits. This can be observed in the effects caused on the
mostly brick and concrete buildings, which even outside of the
cloud, can be seen badly damaged, on support of our modeling of the
vapor cloud boundaries.
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Update: More detailed aerial pictures, later available, tend to
confirm the modeling results. From these, it can be observed a
clear delineation resulting from high temperature gradients (as
seen in burned vegetation) which results to be different from the
shock wave front effects, which is mostly observed by the affected
structures and how these are geographically distributed. A more
detailed simulation of dynamic type can be derived from these
results.Shock Wave Propagation Path