Amuay UCVE Event Aug 25 2012 (Saturday)

around 1:10 AM

Disclaimer: 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

In Amuay olefins are produced inthe cat cracking and in the coking operations

Olefins are used to produce alkylate, amotor gasoline component

for octane improvement

Olefins are stored in spherical tanks due to itshigh vapor pressure and low boiling point

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”

Insiders reported that a olefins

pump was leaking…a pump

seal failure perhaps?

In Amuay the strong prevailing trade winds

blow there most of the year

These are a key design and operational factor

Wind

Olefins pump leak not fixed, last for days

Randomly, during August and September, and before a downpour

prevalent winds may slow, sometimes change direction,

from its regular eastwarddirection

Wind

Olefins pump leak not fixed, last for days

In the preceding days, atmospheric conditions caused showers in the area,

the wind to erratically slow and change direction

Win

dOlefins pump leak not fixed, last for days

Olefins pump leak not fixed, last for days

An operational decision seems to have been madeto maintain the equipment in

operation 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 flammable

Click to continue

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 quality

Wind

Leak source

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 night

Wind

Leak source

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 becomes

much larger

Wind

Leak source

Leak source

Wind

Leak source

Low points/ path

Low points/ path

Wind

Leak source

Wind

Low points/ path

Low points/ path

Leak source

Wind

Leak source

Wind

Leak source

Wind

Leak source

Wind

Leak source

Wind

Leak source

One worker is on the pedestrian overpass, walks

away, leaving the area

National Guards livehere with their families

Wind

Leak source

One worker is on the pedestrian overpass, walks

away, leaving the area

One vehicle southbound approaches the vapor

cloud

Lube oil plant team is still at work

Wind

Leak source

One worker is on the pedestrian overpass, walks

away, leaving the area

One vehicle southbound approaches the vapor

cloud

Lube oil plant team is still at work

Wind

Leak source, now ignited, can be seen in the next

photographs

The worker on the pedestrian overpass dies

Likely the car ignites the cloud here. The explosion force

pushes it towards the opposite curb as seen in the attached

pic

Five lube oil plant workers perish while still at work

Many people, houses are affected by the strong

shock

Many people, houses are affected by the strong

shock

Wind

Olefins pump site

Olefins pump site

Overpass damage pic 2

House damage pic 1

Lube oil plant damages pic 5

Wind

Business damage pic 3

Lube oil plant damages pic 6

Business damage pic 4

1

2

3

4

5

6

The operational decisionto maintain the equipment in

operation 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…

"I am living miracle.. it was not my time", said Edino Rafael Muñoz 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 him…

Link: http://www.ultimasnoticias.com.ve/Noticias/Actualidad/Sucesos/Testimonio-en-Amuay---Estoy-vivo-de-milagro--no-me.aspx

Unconfined Vapor Cloud Explosion

UVCE

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.

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